Reciprocating positive displacement pump

Abstract

To provide a pump that imparts low shear force and turbulence to a fluid being pumped.SOLUTION: A reciprocating positive-displacement pump comprises: a hemispherical rigid chamber wall; a flexible membrane attached to the rigid chamber wall so that the flexible membrane and rigid chamber wall define a pumping chamber; an inlet for directing the flow through the rigid chamber wall into the pumping chamber in a direction that is substantially tangential to the rigid chamber wall; and an outlet for directing the flow through the rigid chamber wall out of the pumping chamber in a direction that is substantially tangential to the rigid chamber wall.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] This application claims priority from the following U.S. provisional patent applications, all of which are incorporated herein by reference in their entireties: U.S. Provisional Patent Application No. 60 / 792,073, filed April 14, 2006, entitled "Extracorporeal Thermal Therapy Systems and Methods"; U.S. Provisional Patent Application No. 60 / 835,490, filed Aug. 4, 2006, entitled "Extracorporeal Thermal Therapy Systems and Methods"; U.S. Provisional Patent Application No. 60 / 904,024, filed February 27, 2007, entitled "Hemodialysis System and Methods"; and U.S. Provisional Patent Application No. 60 / 921,314, filed April 2, 2007, entitled "Sensor Apparatus."

[0002] This application is further related to the following U.S. patent applications, all of which were filed on even date herewith and are incorporated by reference in their entireties: U.S. patent application, "HEAT EXCHANGE SYSTEMS, DEVICES AND METHODS" (Attorney Docket No. 1062 / E77); U.S. patent application, "LIQUID PUMPING SYSTEM, DEVICE AND METHOD" (Attorney Docket No. 1062 / E78); and U.S. patent application, "THERMAL AND CONDUCTIVITY SENSING SYSTEMS, DEVICES, AND METHODS" (Attorney Docket No. 1062 / E79).

[0003] This application is further related to U.S. patent application Ser. No. 10 / 697,450, filed Oct. 30, 2003, published as U.S. Patent Application Publication No. 2005 / 0095154 (Attorney Docket No. 1062 / D75), entitled "BEZEL ASSEMBLY FOR PNEUMATIC CONTROL," and to related International Application No. PCT / US2004 / 035952, filed Oct. 29, 2004, published as WO 2005 / 044435 (Attorney Docket No. 1062 / D71WO), entitled "BEZEL ASSEMBLY FOR PNEUMATIC CONTROL," both of which are incorporated herein by reference in their entireties.

[0004] Additionally, U.S. Patent Nos. 4,808,161; 4,826,482; 4,976,162; 5,088,515; and 5,350,357 are incorporated herein by reference in their entireties.

[0005] The present invention relates to pumps and other flow control systems and methods, and more particularly to pumps that impart low shear and turbulence to the fluid being pumped. [Background technology]

[0006] As is well known in the art, extracorporeal heating can be used to alter a patient's body temperature to treat a variety of diseases, such as Hepatitis C or, in some cases, certain cancers, HIV / AIDS, rheumatoid arthritis, and psoriasis. To warm the blood for a sufficient period of time, a large flow rate is required from the patient's body to the warmer and back to the patient.

[0007] In prior art systems, centrifugal pumps have been used to provide relatively high flow rates of blood into and out of the patient's body. While centrifugal pumps provide the required high flow rates, they also subject the blood to relatively high shear forces, which can lead to undesirable amounts of hemolysis. Hemolysis is of particular concern with warmed blood because red blood cell membranes are weakened at high temperatures, making red blood cells highly susceptible to rupture when subjected to shear forces at high temperatures.

[0008] Due to the high flow of blood into and out of the patient, a leak in the system can quickly result in the death of the patient.

[0009] Furthermore, prior art systems typically involve bulky and relatively unresponsive equipment and there is a time lag when transferring the system from one patient to the next, increasing the risk of improperly configuring the system. Summary of the Invention [Means for solving the problem]

[0010] According to one aspect of the invention, there is provided a reciprocating positive displacement pump comprising: a rigid chamber wall that is hemispherical; a flexible membrane attached to the rigid chamber wall such that the flexible membrane and the rigid chamber wall define a pumping chamber; an inlet that directs flow through the rigid chamber wall into the pumping chamber in a direction substantially tangential to the rigid chamber wall; and an outlet that directs flow through the rigid chamber wall out of the pumping chamber in a direction substantially tangential to the rigid chamber wall.

[0011] In accordance with another aspect of the present invention, a reciprocating positive displacement pump is provided that includes a rigid chamber wall that is hemispherical; a flexible membrane attached to the rigid chamber wall such that the flexible membrane and the rigid chamber wall define a pumping chamber; an inlet that directs flow through the rigid chamber wall into the pumping chamber in a direction to provide a low shear flow into the pumping chamber; and an outlet that directs flow through the rigid chamber wall out of the pumping chamber in a direction to provide a low shear flow out of the pumping chamber.

[0012] According to another aspect of the present invention, there is provided a reciprocating positive displacement pump comprising: a rigid chamber wall that is semi-spheroidal, the wall having a perimeter; a flexible membrane attached to the periphery of the wall such that the flexible membrane and the rigid chamber wall define a pumping chamber; an inlet for directing flow into the pumping chamber through the rigid chamber wall; and an outlet for directing flow out of the pumping chamber through the rigid chamber wall, the outlet being spaced from the periphery of the wall, wherein the membrane is made of silicone.

[0013] According to another aspect of the invention, there is provided a reciprocating positive displacement pump comprising: a rigid chamber wall that is hemispheroidal, the wall having a perimeter; a flexible membrane attached to the periphery of the wall such that the flexible membrane and the rigid chamber wall define a pumping chamber; an inlet for directing flow into the pumping chamber through the rigid chamber wall; and an outlet for directing flow out of the pumping chamber through the rigid chamber wall, the outlet being spaced from the periphery of the wall, wherein the membrane includes a bump that spaces a central portion of the membrane from the rigid chamber wall when the membrane is in a minimum pumping chamber volume position.

[0014] In various alternative embodiments, the rigid chamber wall may have a perimeter. A flexible membrane may be attached to the perimeter of the wall. The outlet may be spaced from the perimeter. The membrane may be made of silicone, e.g., high elongation silicone, or other suitable material. The membrane may include a bump or other feature that spaces a central portion of the membrane from the rigid chamber wall when the membrane is in a minimum pumping chamber volume position. The inlet may be oriented to create a circulating fluid flow in the pumping chamber toward the outlet, and the outlet may be oriented such that flow directed out of the pumping chamber delaminates from the circulating flow.

[0015] In a further embodiment, a rigid limit structure may be further included to limit movement of the membrane and limit a maximum volume of the pumping chamber, the flexible membrane and the rigid limit structure defining an actuation chamber. The actuation chamber may be adapted to be actuated by a pressurized control fluid and the rigid limit structure may include an integral actuation port. The rigid chamber wall and the rigid limit structure may be interconnected, for example by ultrasonic welding. The membrane may be held in place between the rigid chamber wall and the rigid limit structure. The rigid limit structure may limit movement of the flexible membrane such that the rigid chamber and the flexible membrane pressed against the rigid limit structure define the pumping chamber as a spherical volume when the pumping chamber is at maximum volume. The rigid limit structure may be a hemispherical limit wall that together with the flexible membrane defines a spherical actuation chamber when the pumping chamber is at minimum volume.

[0016] In a further embodiment, the pump may further include an inlet valve to prevent flow from exiting the pumping chamber through the inlet, and an outlet valve to prevent flow from entering the pumping chamber through the outlet. The inlet and outlet valves may be passive check valves or actively controlled valves. The pump may be adapted to pump liquid, biological liquid, blood, or warm blood.

[0017] In further embodiments, the pump may further comprise a purge port in fluid communication with the pumping chamber, the purge port allowing for the expulsion of air from the pumping chamber. The pump may further comprise a secondary inlet in fluid communication with the pumping chamber, the secondary inlet allowing for the introduction of a secondary fluid into the pumping chamber. The secondary inlet may be a luer port, a syringe port, or a hollow needle. The secondary fluid may be a medical solution, a chemical solution, a diluent, a blood thinner, or an anticoagulant.

[0018] According to another aspect of the invention, there is provided a pumping system comprising a pair of reciprocating positive displacement pumps of any type; an inlet tube connected to the inlets of both pumps; and an outlet tube connected to the outlets of both pumps. The pair of reciprocating positive displacement pumps may be configured to allow independent operation of the pumps to provide various flow patterns through the inlet and outlet tubes. The pumps may be pneumatically or hydraulically actuated and may include independent actuation ports for each pump or a single actuation port for both pumps.

[0019] According to another aspect of the invention, there is provided a system for pumping a biological fluid comprising a disposable unit, first and second spheroidal pump pods, and a base unit. The disposable unit includes an inlet tube for the biological fluid, and an outlet tube for the biological fluid. Each pump pod includes a rigid chamber wall that is hemispherical, a rigid actuation wall that is hemispherical, a flexible membrane attached to the chamber wall and the actuation wall such that the flexible membrane and the chamber wall define a pumping chamber and the flexible membrane and the actuation wall define an actuation chamber, an inlet valve that allows flow from the inlet tube into the pumping chamber but prevents flow out of the pumping chamber into the inlet tube, an outlet valve that allows flow from the pumping chamber into the outlet tube but prevents flow from the outlet tube into the pumping chamber, and an actuation port that provides fluid communication with the actuation chamber. The base unit includes a container means for receiving and holding the disposable unit, and an actuation system for supplying a control fluid under positive or negative pressure to each of the actuation ports.

[0020] In various alternative embodiments, the first and second pump pods may be rigidly attached to one another and the container means may include means for receiving the first and second pump pods in one step. The base unit may further include first and second pressure transducers for measuring the pressure of a control fluid supplied to the actuation port of the first pump pod and the pressure of a control fluid supplied to the actuation port of the second pump pod, respectively, and a controller for receiving pressure information from the first and second pressure transducers to control the actuation system and for controlling the actuation system. The controller may be adapted to cause the actuation system to operate the pump pods out of phase with one another such that the pumping chamber of one pump pod is substantially full when the pumping chamber of the other pump pod is substantially empty.

[0021] According to another aspect of the invention, there is provided a disposable unit for use in a system for pumping a biological fluid. The disposable unit includes an inlet tube for the biological fluid; an outlet tube for the biological fluid; and first and second spheroidal pump pods. Each pump pod includes a rigid chamber wall that is hemispherical, a rigid actuation wall that is hemispherical, a flexible membrane attached to the chamber wall and the actuation wall such that the flexible membrane and the chamber wall define a pumping chamber and the flexible membrane and the actuation wall define an actuation chamber, an inlet valve that allows flow from the inlet tube into the pumping chamber but prevents flow from the pumping chamber into the inlet tube, an outlet valve that allows flow from the pumping chamber into the outlet tube but prevents flow from the outlet tube into the pumping chamber, and an actuation port that provides fluid communication with the actuation chamber.

[0022] In various alternative embodiments, each pump pod may include an inlet that directs flow through the rigid chamber wall into the pumping chamber in a direction that provides a low shear flow into the pumping chamber, and an outlet that directs flow through the rigid chamber wall out of the pumping chamber in a direction that provides a low shear flow out of the pumping chamber. Each pump pod may include an inlet that directs flow through the rigid chamber wall into the pumping chamber in a direction that is substantially tangential to the rigid chamber wall, and an outlet that directs flow through the rigid chamber wall out of the pumping chamber in a direction that is substantially tangential to the rigid chamber wall.

[0023] In a further embodiment, the disposable unit may further include a heat exchanger component in fluid communication with the first and second spheroidal pump pods, the heat exchanger component adapted to be received in a heat exchanger that warms the biological fluid. The heat exchanger component may include a flexible bag defining a fluid path.

[0024] According to another aspect of the invention, a system for pumping a biological fluid is provided. The system includes a disposable unit, first and second pump pods, and a base unit. The disposable unit includes an inlet tube for the biological fluid and an outlet tube for the biological fluid. Each pump is capable of delivering a stroke volume during each stroke and includes a rigid pod wall surrounding a pump chamber, a reciprocating member adjacent the pump chamber, an inlet valve permitting flow from the inlet tube into the pumping chamber but preventing flow from the pumping chamber into the inlet tube, an outlet valve permitting flow from the pumping chamber into the outlet tube but preventing flow from the outlet tube into the pumping chamber, and an actuation port defined by the rigid pod wall. The base unit includes a container means for receiving and holding the disposable unit, and an actuation system for supplying a control fluid under positive or negative pressure to each of the actuation ports, such that the base unit is capable of receiving and holding disposable units having pod pumps with different stroke volumes.

[0025] According to another aspect of the invention, there is provided a base unit for pumping a biological fluid, the base unit including a container means for receiving and holding a disposable unit and an actuation system for supplying a control fluid to the disposable unit under positive or negative pressure, the base unit being capable of receiving and holding a disposable unit having pod pumps with different output volumes, the disposable unit including first and second pump pods each capable of delivering a certain output volume during each stroke, each pump pod having a rigid pod wall surrounding a pump chamber and an actuation port defined by the rigid pod wall for permitting fluid communication between the actuation system and a reciprocating member.

[0026] In accordance with another aspect of the invention, a pump is provided that includes a means for drawing fluid into or pushing fluid out of a pumping chamber; a means for determining a flow rate through the pumping chamber; and a controller that determines the work required to achieve the flow rate and issues an alert if the work rate indicates an abnormal flow condition.

[0027] According to another aspect of the invention, there is provided a reciprocating positive displacement pump comprising: a rigid chamber wall; a flexible membrane attached to the rigid chamber wall such that the flexible membrane and the rigid chamber wall define a pumping chamber; an inlet for directing flow into the pumping chamber through the rigid chamber wall; an outlet for directing flow out of the pumping chamber through the rigid chamber wall; a rigid restriction wall for restricting movement of the membrane and limiting a maximum volume of the pumping chamber, the flexible membrane and the rigid restriction wall forming an actuation chamber, the rigid chamber wall and the rigid restriction wall providing a physical limit to movement of the flexible membrane through a stroke; an actuation system for intermittently supplying positive or negative pressure to the actuation chamber; an actuation chamber pressure transducer for measuring pressure in the actuation chamber; and a controller for receiving pressure information from the actuation chamber pressure transducer and controlling the actuation system to cause the flexible membrane to reach the physical limit at the beginning and end of a stroke, the controller determining an amount of flow through the pump based on the number of strokes, and the controller integrating the pressure information from the actuation chamber pressure transducer over a period of one stroke to detect abnormal flow conditions.

[0028] According to another aspect of the invention, a method of controlling flow is provided that includes pumping fluid through a pumping chamber by at least one of drawing fluid into the pumping chamber and pushing fluid out of the pumping chamber; determining a flow rate through the pumping chamber; determining a work rate required to achieve the flow rate; and issuing an alert when the work rate related to the flow rate indicates an abnormal flow condition.

[0029] In various alternative embodiments, pumping a fluid, determining the flow rate, and determining the work rate may include providing a rigid chamber wall and a flexible membrane attached to the rigid chamber wall such that the flexible membrane and the rigid chamber wall define a pumping chamber; providing an inlet for directing flow into the pumping chamber through the rigid chamber wall and an outlet for directing flow out of the pumping chamber through the rigid chamber wall; a rigid limiting wall for restricting movement of the membrane and limiting a maximum volume of the pumping chamber, wherein the flexible membrane and the rigid limiting wall form an actuation chamber, and the rigid chamber wall and the rigid limiting wall act to move the fluid through a stroke. providing a restricting wall that provides a physical limit to the movement of the flexible membrane; providing an actuation system that intermittently supplies positive or negative pressure to the actuation chamber; providing an actuation chamber pressure transducer that measures pressure in the actuation chamber; receiving pressure information from the actuation chamber pressure transducer; controlling the actuation system to cause the flexible membrane to reach the physical limit at the beginning and end of a stroke; determining an amount of flow through the pump based on the number of strokes; and integrating the pressure information from the actuation chamber pressure transducer over a period of one stroke to detect abnormal flow conditions.

[0030] According to another aspect of the invention, there is provided a reciprocating positive displacement pump comprising a reciprocating member having a first surface facing a pumping chamber and a second surface facing an actuation chamber, an inlet for directing flow into the pumping chamber, an outlet for directing flow out of the pumping chamber, an actuation chamber pressure transducer for measuring a pressure in the actuation chamber, an actuation system for intermittently providing positive or negative pressure to the actuation chamber, and a controller. The actuation system includes a reservoir containing a control fluid under positive or negative pressure, a valve mechanism for controlling flow of the control fluid between the actuation chamber and the reservoir, and a reservoir pressure transducer for measuring a pressure of the control fluid in the reservoir. The controller, which controls the actuation system to move the reciprocating member, receives pressure information from the actuation chamber pressure transducer and the reservoir pressure transducer and compares the pressure information to determine if either of the pressure transducers is malfunctioning.

[0031] According to another aspect of the invention, there is provided a reciprocating positive displacement pump comprising a rigid chamber wall, a flexible membrane attached to the rigid chamber wall such that the flexible membrane and the rigid chamber wall define a pumping chamber, an inlet for directing flow into the pumping chamber through the rigid chamber wall, an outlet for directing flow out of the pumping chamber through the rigid chamber wall, a rigid actuation wall where the flexible membrane and the rigid restricting wall form an actuation chamber, an actuation chamber pressure transducer for measuring pressure in the actuation chamber, and an actuation system for alternately supplying positive and negative pressures to the actuation chamber, the actuation system including a positive pressure reservoir, a negative pressure reservoir, a valving mechanism for controlling flow of a control fluid between each of the actuation chamber and the reservoirs, a positive pressure reservoir pressure transducer for measuring pressure in the positive pressure reservoir, and a negative pressure reservoir pressure transducer for measuring pressure in the negative pressure reservoir. A controller controls the actuation system to move the flexible membrane, receives pressure information from the actuation chamber pressure transducer, the positive pressure reservoir pressure transducer and the negative pressure reservoir pressure transducer, and compares the pressure information to determine if any of the pressure transducers are malfunctioning.

[0032] According to another aspect of the invention, a valve system is provided. The valve system includes a valve cassette and a control cassette. The valve cassette contains a plurality of valves, each valve including a valve chamber and an actuation chamber, each valve actuable by a control fluid in the actuation chamber. The control cassette has a plurality of fluid interface ports providing fluid communication with the control fluid from a base unit. A plurality of tubes extend between the pump cassette and the control cassette. Each tube provides fluid communication between one of the fluid interface ports and at least one of the actuation chambers such that the base unit can actuate one of the valves by pressurizing the control fluid in one of the fluid interface ports.

[0033] In various alternative embodiments, the pumping system may include a pump cassette containing a plurality of pumps, each pump including a pumping chamber and an actuation chamber, each pump actuable by a control fluid in the actuation chamber; a control cassette having a plurality of fluid interface ports providing fluid communication with the control fluid from a base unit; and a plurality of tubes extending between the pump cassette and the control cassette, each tube providing fluid communication between one of the fluid interface ports and at least one of the actuation chambers, such that the base unit can actuate a pump by pressurizing the control fluid in the one of the fluid interface ports. The pump cassette may include valves actuable by the control fluid, and the plurality of tubes may include a tube providing fluid communication between one of the fluid interface ports and the valve, such that the base unit can actuate the valve by pressurizing the control fluid in the one of the fluid interface ports.

[0034] According to another aspect of the present invention, there is provided a diaphragm for use in a reciprocating positive displacement pump having a circular periphery and a preformed hemispheroidal membrane attached to the periphery, the membrane may include a raised structure arrangement on the pump chamber side.

[0035] According to another aspect of the invention, there is provided a diaphragm for use in a reciprocating positive displacement pump, the diaphragm having a periphery and a membrane attached to the periphery, the membrane including a configuration of raised structures on a pump chamber side. The raised structures may include raised bumps. The raised structures may be located at a distance from the periphery. The periphery may be adapted to interconnect with at least one of a pump chamber wall and an actuation chamber wall. The periphery and membrane may be made of silicone, for example high elongation silicone. The periphery and membrane may be integral.

[0036] According to another aspect of the present invention, a pumping system is provided in which operation of the pump pod is independent of pump volume by comprising an actuation system for operating a pump pod, the actuation system including a standardized actuation interface for interconnection with pump pods having different pump volumes; an actuation chamber pressure transducer for measuring pressure in an actuation chamber of the pump pod; and a controller for controlling the actuation system to operate the pump pod based on pressure information received from the actuation chamber pressure transducer.

[0037] According to another aspect of the present invention, a pumping system is provided in which operation of the pump pod is independent of stroke length by comprising an actuation system for operating a pump pod, the actuation system including a standardized actuation interface for interconnection with pump pods of different stroke lengths; an actuation chamber pressure transducer for measuring pressure in an actuation chamber of the pump pod; and a controller for controlling the actuation system to operate the pump pod based on pressure information received from the actuation chamber pressure transducer.

[0038] According to another aspect of the invention, a pod pump is provided comprising a three-piece housing defining an internal chamber, the housing having a two-piece pumping chamber wall coupled to an actuation chamber wall; and a diaphragm secured to the housing within the internal chamber, the diaphragm dividing the internal chamber into a pumping chamber and an actuation chamber, the housing including a first port in fluid communication with the actuation chamber and at least one second port in fluid communication with the pumping chamber. The three pieces of the housing may be interconnected by ultrasonic welding. The pod pump may further include a valve for each of the second ports secured between the two pieces of the pumping chamber wall.

[0039] In accordance with another aspect of the present invention, a pod pump is provided comprising: a housing defining an internal chamber; and a diaphragm secured to the housing within the internal chamber, the diaphragm dividing the internal chamber into a pumping chamber and an actuation chamber, the housing including a single port in communication with the pumping chamber for use as both a fluid inlet and a fluid outlet.

[0040] According to another aspect of the invention, a pod pump is provided that includes a housing defining an internal chamber; a diaphragm secured to the housing within the internal chamber, the diaphragm dividing the internal chamber into a pumping chamber and an actuation chamber; and components disposed within the actuation chamber to at least one of: limiting motion of the diaphragm, dampening movement of the diaphragm, filtering fluid flowing into or out of the actuation chamber, dampening sound or vibration of the pod pump, and performing fluid management system measurements on fluid in the pumping chamber.

[0041] In the above type of embodiment, the pump may include or be used with an actuation system that intermittently provides positive or negative pressure to the actuation chamber. The actuation system may include a reservoir containing a control fluid at positive or negative pressure, and a valving mechanism that controls the flow of the control fluid between the actuation chamber and the reservoir. The valving mechanism may include a binary on-off valve or a variable throttle valve. The pump may further include an actuation chamber pressure transducer that measures the pressure of the actuation chamber, and a controller that receives pressure information from the actuation chamber pressure transducer and controls the valving mechanism. The controller may be adapted to dither the valving mechanism and determine when a pump stroke is completed from the pressure information received from the actuation chamber pressure transducer. The controller may be adapted to control the valving mechanism to cause the flexible membrane to reach a rigid chamber wall or a rigid limiting structure at the beginning and end of each stroke to determine the amount of flow through the pump based on the number of strokes. The controller may be adapted to integrate pressure information from the actuation-chamber pressure transducer over a stroke period to detect abnormal flow conditions. The pump may further include a reservoir pressure transducer measuring a pressure of the gas in the reservoir, the controller receiving pressure information from the reservoir pressure transducer. The controller may be adapted to compare pressure information from the actuation-chamber pressure transducer and the reservoir pressure transducer to determine whether either is malfunctioning.

[0042] In the above type of embodiment, the pump may include or be used with an actuation system that alternately supplies positive and negative pressures to the actuation chamber. The actuation system may include a positive pressure reservoir; a negative pressure reservoir; and a valving mechanism that controls the flow of control fluid between the actuation chamber and each of the reservoirs. The valving mechanism may include separate positive and negative supply valves, each of which is one of a binary on-off valve and a variable throttle valve, that control the flow of control fluid between the actuation chamber and the positive and negative pressure reservoirs; or a three-way supply valve that controls the flow of control fluid between the actuation chamber and the positive and negative pressure reservoirs. The pump may further include an actuation chamber pressure transducer that measures the pressure in the actuation chamber, and a controller that receives pressure information from the actuation chamber pressure transducer and controls the valving mechanism. The controller may be adapted to dither the valving mechanism and determine when a pump stroke is complete from the pressure information received from the actuation chamber pressure transducer. The controller may be adapted to control the valving mechanism to cause the flexible membrane to reach the rigid chamber wall or rigid limiting structure at the beginning and end of a stroke, respectively, and the controller determines the amount of flow through the pump based on the number of strokes. The controller may be adapted to integrate pressure information from the actuation chamber pressure transducer over a stroke period to detect an abnormal flow condition. The pump may further include a positive pressure reservoir pressure transducer measuring a pressure in the positive pressure reservoir and a negative pressure reservoir pressure transducer measuring a pressure in the negative pressure reservoir, and the controller receives pressure information from the positive pressure reservoir pressure transducer and the negative pressure reservoir pressure transducer. The controller may be adapted to compare pressure information from the actuation chamber pressure transducer, the positive pressure reservoir pressure transducer and the negative pressure reservoir pressure transducer to determine whether any of the pressure transducers is malfunctioning.

[0043] In any of the above embodiments, the pressure in the reservoir(s) may be controlled so that the pressure in the reservoir(s) does not exceed a preset limit.

[0044] In some embodiments, a pump pod configuration is provided that reduces shear on the fluid being pumped, and reduces hemolysis when used to pump blood, particularly warm blood.

[0045] According to one aspect of the present invention, a sensing probe is provided that includes a probe housing; a thermal sensor in the probe housing having a sensing end and a connector end; a probe tip thermally coupled to the sensing end of the thermal sensor and attached to the probe housing, the probe tip adapted to be thermally coupled to an inner surface of a thermowell; and at least two leads connected to the connector end of the thermal sensor, whereby thermal energy is transferred from the thermowell to the thermal sensor and temperature information is transmitted through the leads. In various alternative embodiments, the sensing probe may further include a third lead attached to one of the probe housing, the thermal sensor, and the probe tip, enabling conductivity sensing. Alternatively, the sensing probe may further include a conductivity sensor attached to one of the probe housing, the thermal sensor, and the probe tip, enabling conductivity sensing; and a third lead attached to the conductivity sensor, transmitting conductivity information. A urethane resin may be included between the probe tip and the probe housing. The probe tip may include a flange that mates with the housing.

[0046] In another aspect of the invention, a sensing probe is provided that includes a probe housing having a probe tip adapted to be thermally coupled to an inner surface of a thermowell; a thermal sensor in the housing having a sensing end and a connector end, the sensing end thermally coupled to the probe tip; and at least three leads, the leads transmitting electrical signals whereby the signals are used to determine temperature and conductivity. In various alternative embodiments, the sensing probe may further include a conductivity sensor attached to the housing, at least one of the leads being attached to the conductivity sensor for transmitting conductivity information.

[0047] In various alternative embodiments of the sensing probe, a thermal epoxy may be included between the thermal sensor and the probe tip. The probe tip may be copper, steel, or metal including at least one of silver, copper, steel, and stainless steel. In various embodiments, the housing may be plastic or metal. The housing may further include a flange disposed about the probe housing, and a spring may be used in conjunction with the flange. The housing may include an integrated flexible member.

[0048] In accordance with another aspect of the present invention, a sensor device is described. The sensor device includes a probe housing having a probe tip. Additionally, a thermal sensor within the housing having a sensing end and a connector end. The sensing end is thermally coupled to the probe tip. The sensor device further includes at least three leads. The leads transmit electrical signals. The signals are used to determine temperature and conductivity.

[0049] Some embodiments of this aspect of the invention include a thermowell of a predetermined size and shape that mates with the probe, with the probe tip being thermally coupled to the thermowell.

[0050] According to one aspect of the invention, there is a thermowell. The thermowell includes a hollow housing made of a thermally conductive material. The housing has an exterior surface and an interior surface. The interior surface has a predetermined shape to form a mating relationship with a sensing probe. The mating thermally couples the interior surface to the sensing probe.

[0051] Certain embodiments of this aspect of the invention include a volume of thermal grease on an inner surface of the thermowell. According to one aspect of the invention, a method for determining the temperature and conductivity of a target medium is described. The method includes the steps of thermally coupling a thermowell and a sensing probe such that the temperature and conductivity can be determined; transmitting temperature and conductivity signals from the sensing probe through at least three leads; and determining the temperature and conductivity using the signals.

[0052] According to another aspect of the invention, a method of detecting air in a fluid line is described, the method including the steps of thermally coupling at least two thermowells located in the fluid line to sensing probes so that temperature and conductivity can be determined, transmitting conductivity signals from the sensing probes through at least three leads, determining the conductivity for each sensing probe, calculating the difference in conductivity from each sensing probe, and determining whether the difference exceeds a threshold value.

[0053] In accordance with another aspect of the invention, an apparatus is provided that includes a fluid conduit including a well for at least one of transmitting temperature of a fluid passing through the conduit and enabling conductivity sensing, the well adapted to interconnect with a sensor.

[0054] In various alternative embodiments, the device may be configured such that a portion of the well contacts the fluid in the conduit, or such that no portion of the well contacts the fluid in the conduit. The fluid conduit may include plastic or metal tubing.

[0055] The well and the conduit may be integrally formed from the same material.

[0056] Alternatively, the well may be coupled to the fluid conduit using, for example, at least one of a press-fit connection, a flexible tab, an adhesive, ultrasonic welding, and a retaining plate and fastener. An O-ring may be disposed between the well and the fluid conduit. The O-ring may include one of a round cross-section, a square cross-section, and an X-shaped cross-section. The well may include a groove for receiving a portion of the O-ring. The portion of the well in contact with the conduit may be flexible to deform the conduit and may include a plurality of notches to provide such flexibility.

[0057] Alternatively, the well may be embedded in the fluid conduit, for example insert molded into the fluid conduit.

[0058] The well and the conduit may be made of different materials, for example the conduit may be plastic and the well metal. The well may include protrusions that help secure the well to the conduit.

[0059] The conduit may have an inner surface and an outer surface such that the sensor end of the well is flush with, protrudes beyond, or is recessed from the outer surface.

[0060] According to another aspect of the invention, there is provided a fluid pumping device comprising at least one pump and a well for transmitting temperature and / or enabling conductivity sensing of a fluid passing through a conduit, the well adapted to interface with a sensor. In various alternative embodiments, the at least one pump may comprise at least one pod pump or may comprise a pair of pod pumps. The at least one pump and the well may be incorporated into a cassette.

[0061] According to another aspect of the invention there is provided a sensing system comprising a sensing probe of the type described above and a well of the type described above, the well being in communication with the sensing probe for at least one of thermal and conductivity sensing.

[0062] According to one aspect of the invention, there is provided a method of heating or cooling a fluid, comprising the steps of: At least one reciprocating positive displacement pump, each Curved, rigid chamber walls; a flexible membrane attached to the rigid chamber wall such that the flexible membrane and the rigid chamber wall define a pumping chamber; an inlet for directing fluid entering the pumping chamber through the rigid chamber wall in at least one of: (a) a direction substantially tangential to the rigid chamber wall; and (b) a direction providing low shear flow into the pumping chamber; and providing a pump having an outlet that directs fluid exiting the pumping chamber through the rigid chamber wall in at least one of: (a) a direction substantially tangential to the rigid chamber wall; and (b) a direction that provides low shear flow exiting the pumping chamber; Providing a heat exchanger; and pumping the fluid from the source through the heat exchanger with at least one reciprocating positive displacement pump; A method is provided comprising:

[0063] According to another aspect of the present invention, there is provided a disposable unit for use in a heat exchanger system, comprising: At least one reciprocating positive displacement pump, each curved, solid chamber walls; a flexible membrane attached to the rigid chamber wall such that the flexible membrane and the rigid chamber wall define a pumping chamber; an inlet for directing fluid entering the pumping chamber through the rigid chamber wall in at least one of: (a) a direction substantially tangential to the rigid chamber wall; and (b) a direction providing low shear flow entering the pumping chamber; and a pump having an outlet that directs fluid exiting the pumping chamber through a rigid chamber wall in at least one of: (a) a direction substantially tangential to the rigid chamber wall; and (b) a direction that provides low shear flow exiting the pumping chamber; and a heat exchanger component adapted to be received in the heat exchanger and in fluid communication with the at least one pump; A disposable unit is provided comprising:

[0064] According to another aspect of the present invention, a heat exchanger for receiving the heat exchanger components of the disposable unit; a pneumatic actuation system that operates at least one pump of the disposable unit to pump fluid through the heat exchanger component; and A controller for controlling a pneumatic actuation system A heat exchanger system is provided comprising:

[0065] In some embodiments, the disposable unit may be considered to be part of the heat exchanger system.

[0066] In accordance with another aspect of the present invention, there is provided a method for transferring blood between a patient access device and a heat exchanger for warming the blood, the method comprising the steps of: Providing a reciprocating positive displacement pump; providing a flow conduit having a first portion between a patient access device and a pump and a second portion between the pump and a heat exchanger; providing a valve in each of the first and second portions of the flow tube to permit flow through the flow tube in only one direction; and activating a pump to create blood flow between the patient access device and the heat exchanger; A method is provided comprising:

[0067] According to another aspect of the present invention, there is provided a system for extracorporeal hyperthermia treatment, comprising: a heat exchanger to warm the blood; a reciprocating positive displacement pump for moving blood between a patient access device and a heat exchanger, the pump having an inlet tube and an outlet tube; a first valve located in the inlet tube to prevent the flow of blood out of the pump; and A second valve located in the outlet tube that prevents blood flow into the pump. A system is provided comprising:

[0068] According to another aspect of the invention, there is provided a heat exchanger for warming extracorporeal blood for thermal treatment, comprising a pump according to any one of the preceding claims, a heat exchange flow path having an inlet for unwarmed blood and an outlet for warmed blood; an electrothermal converter that converts electrical power into heat that is absorbed by the blood; a first temperature sensor located at the inlet for measuring the temperature of blood entering the heat exchanger; a second temperature sensor located at the outlet for measuring the temperature of the blood exiting the heat exchanger; a measurement system for measuring the flow rate of blood passing through the heat exchanger; and A heat exchanger is provided that further includes a controller in communication with the converter, the first and second temperature sensors, and the measurement system, the controller receiving information regarding the amount of power being used by the converter, receiving temperature information from the first and second temperature sensors, receiving flow rate information from the measurement system, analyzing the received information to determine if a fault condition exists, and issuing a signal if a fault condition is detected.

[0069] According to another aspect of the present invention, there is provided a heat exchanger for warming extracorporeal blood for hyperthermia treatment, comprising: inlet for unwarmed blood; Outlet for warming blood; flow path from inlet to outlet; a set of heating elements overlying the flow path and including at least a first and a second heating element, the second heating element being positioned proximate the flow path near the outlet and the first heating element being positioned proximate the flow path at a point upstream of the second heating element; a first temperature sensor located adjacent the flow path upstream of the first heating element; a second temperature sensor located proximate the flow path between the first and second heating elements; and a controller that receives temperature information from the first and second temperature sensors and generates a signal when a temperature difference being measured by the first and second sensors exceeds a limit; A heat exchanger comprising:

[0070] According to another aspect of the present invention, there is provided a heat exchanger for warming extracorporeal blood for hyperthermia treatment, comprising: inlet for unwarmed blood; Outlet for warming blood; flow path from inlet to outlet; a set of heating elements overlying the flow path and including at least a first, second and third heating element, the third heating element being positioned proximate the flow path near the outlet, the second heating element being positioned proximate the flow path at a point preceding the third heating element, and the first heating element being positioned proximate the flow path at a point preceding the second heating element; a first temperature sensor located proximate the flow path between the first and second heating elements; a second temperature sensor located proximate the flow path between the second and third heating elements; and a controller that receives temperature information from the first and second temperature sensors and generates a signal when a temperature difference being measured by the first and second sensors exceeds a limit; A heat exchanger comprising:

[0071] According to another aspect of the present invention, there is provided a heat exchanger for warming extracorporeal blood for hyperthermia treatment, comprising: inlet for unwarmed blood; Outlet for warming blood; an electrothermal converter that converts electrical power into heat that is absorbed by the blood; a first temperature sensor located at the inlet for measuring the temperature of blood entering the heat exchanger; a second temperature sensor located at the outlet for measuring the temperature of the blood exiting the heat exchanger; a measurement system for measuring the flow rate of blood passing through the heat exchanger; and a controller in communication with the converter, the first and second temperature sensors, and the measurement system, the controller receiving information regarding an amount of power being used by the converter, receiving temperature information from the first and second temperature sensors, receiving flow rate information from the measurement system, analyzing the received information to determine if a fault condition exists, and issuing a signal if a fault condition is detected; A heat exchanger comprising:

[0072] According to another aspect of the present invention, there is provided a heat exchanger for warming extracorporeal blood for hyperthermia treatment, comprising: inlet for unwarmed blood; Outlet for warming blood; an electrothermal converter that converts electrical power into heat that is absorbed by the blood; a disposable unit containing a blood flow path from an inlet to an outlet and made primarily of a thermoplastic material; a conductivity sensor that measures the resistance between the blood in the flow path thermowell and the transducer; and a controller in communication with the conductivity sensor and which generates a signal if the measured resistance does not meet a safety parameter; A heat exchanger comprising:

[0073] According to another aspect of the present invention, there is provided a heat exchanger for warming extracorporeal blood for hyperthermia treatment, comprising: Inlet for unwarmed blood, An outlet for warmed blood, and Blood flow from inlet to outlet a disposable unit having a base unit having a warmer for warming blood in a flow path, the warmer including a first thermally conductive plate for transferring heat to a first side of the disposable unit and a second thermally conductive plate for transferring heat to a second side of the disposable unit opposite the first plate, the first and second plates adapted to push against each other to push blood out of the disposable device upon actuation by a controller; A heat exchanger comprising:

[0074] According to another aspect of the present invention, there is provided a method of positioning a temperature probe for monitoring a patient temperature, comprising the steps of: reading a temperature reading from a first temperature probe positioned at a first location on the patient's body; reading a temperature reading from a second temperature probe positioned at a second location on the patient's body; comparing temperature readings from the first and second probes; positioning first and second temperature probes on a body of a patient; determining whether a temperature reading from the first location or the second location is above a preset limit; and A method is provided that includes issuing a configuration signal if a temperature reading from a first probe is within a preset range of a temperature reading from a second probe and if a reading from the first or second location is above a preset limit.

[0075] According to another aspect of the present invention, there is provided a method of providing hyperthermia treatment to a patient, comprising the steps of: providing a heat exchanger system for warming blood from a patient and pumping the warmed blood to the patient; connecting a first temperature probe from the patient to the heat exchanger system, the heat exchanger system controlling the warming and pumping of blood based on temperature information received from the first temperature probe, and displaying the temperature information received from the first temperature probe to an operator; monitoring the patient temperature with a separate second temperature probe by the operator; and A method is provided that includes terminating treatment if either of the temperature probes delivers an unacceptable temperature reading.

[0076] In some embodiments of the present invention, a pump pod configuration is provided that reduces shear on the fluid being pumped and reduces hemolysis when used to pump blood (especially warm blood).

[0077] In one embodiment of the present invention, a reciprocating positive displacement pump includes a rigid chamber wall that is hemispherical; a flexible membrane attached to the rigid chamber wall such that the flexible membrane and the rigid chamber wall define a pumping chamber; an inlet that directs flow through the rigid chamber wall into the pumping chamber in a direction that provides a low shear flow into the pumping chamber; and an outlet that directs flow through the rigid chamber wall out of the pumping chamber in a direction that provides a low shear flow out of the pumping chamber.

[0078] In one embodiment of the present invention, a reciprocating positive displacement pump is provided that includes a rigid hemispherical chamber wall; a flexible membrane attached to the rigid chamber wall such that the flexible membrane and the rigid chamber wall define a pumping chamber; an inlet that directs flow through the rigid chamber wall into the pumping chamber substantially tangentially to the rigid chamber wall; and an outlet that directs flow through the rigid chamber wall out of the pumping chamber substantially tangentially to the rigid chamber wall. In one embodiment, the reciprocating positive displacement pump further includes a rigid limit structure that limits movement of the membrane and limits a maximum volume of the pumping chamber, the flexible membrane and the rigid limit structure defining an actuation chamber. The rigid limit structure may be adapted to limit movement of the flexible membrane such that when the pumping chamber is at maximum volume, the rigid chamber and the flexible membrane (pressed against the rigid limit structure) define the pumping chamber as a spherical volume. The rigid limiting structure may be a hemispherical limiting wall that together with the flexible membrane defines a spherical actuation chamber when the pumping chamber is at minimum volume.

[0079] In certain embodiments, the reciprocating positive displacement pump includes a pneumatic actuation system that intermittently provides positive or negative pressure to the actuation chamber. In some embodiments, the pneumatic actuation system includes a reservoir containing gas at positive or negative pressure; and a valve mechanism that controls the flow of gas between the actuation chamber and the gas reservoir. The reciprocating positive displacement pump may include an actuation chamber pressure transducer that measures the pressure of the actuation chamber, and a controller that receives pressure information from the actuation chamber pressure transducer and controls the valve mechanism. In certain embodiments, a reservoir pressure transducer is included that measures the pressure of the gas in the reservoir, and the controller receives pressure information from the reservoir pressure transducer. In some embodiments, the controller compares pressure information from the actuation chamber pressure transducer and the reservoir pressure transducer to determine whether either of the pressure transducers is malfunctioning.

[0080] In certain embodiments, the pneumatic actuation system alternately supplies positive and negative pressure to the actuation chamber. In one arrangement, the pneumatic actuation system includes a positive pressure gas reservoir, a negative pressure gas reservoir, and a valving mechanism that controls the flow of gas between each of the actuation chamber and the gas reservoir. Such embodiments may further include an actuation chamber pressure transducer that measures the pressure of the actuation chamber, and a controller that receives pressure information from the actuation chamber pressure transducer and controls the valving mechanism. Additionally, such embodiments may further include a positive pressure reservoir pressure transducer that measures the pressure of the positive pressure gas reservoir, and a negative pressure reservoir pressure transducer that measures the pressure of the negative pressure gas reservoir. A controller receives pressure information from these transducers and analyzes the pressure information to determine if any of the transducers are malfunctioning. The controller also controls the pressure of the reservoir or reservoirs such that the pressure of the reservoir or reservoirs does not exceed a preset limit.

[0081] In certain embodiments, the controller dithers the valving mechanism and determines when a stroke is complete from pressure information from the actuation chamber pressure transducer. In further embodiments, the controller controls the valving mechanism to cause the flexible membrane to reach a solid chamber wall or a solid limiting structure at the beginning and end of a stroke, respectively. In this embodiment, the controller can determine the amount of flow through the pump based on the number of strokes. Additionally, the controller may integrate pressure information from the actuation chamber pressure transducer over the duration of a stroke (or determine the work done during a stroke) as a way of detecting abnormal flow conditions.

[0082] In some embodiments of the invention, the reciprocating positive displacement pump includes an inlet valve that prevents flow out of the pump and an outlet valve that prevents flow into the pump. In some embodiments, these valves are simply passive check valves, while in other embodiments, these valves are actively controlled valves that are controlled to allow fluid to flow in a desired direction. In certain embodiments, the pump is adapted to pump liquids, and in further embodiments, the pump is adapted to pump biological liquids such as blood. As noted above, certain embodiments of the invention are suitably adapted to pump warm blood.

[0083] In certain embodiments, the pumps are paired or ganged such that one inlet line leads to the inlets of both pumps and one outlet line leads to the outlets of both pumps. In such embodiments, the pumps may be operated out of phase such that the pumping chamber of one pump pod is substantially full when the pumping chamber of the other pump pod is substantially empty.

[0084] An embodiment of the present invention further provides a method for warming blood extracorporeally. A method includes the steps of providing a reciprocating positive displacement pump; providing a flow tube having a first portion between a patient access device and the pump and a second portion between the pump and a heat exchanger; providing valves in each of the first and second portions of the flow tube to allow flow through the flow tube in only one direction; and operating the pump to cause blood to flow between the patient access device and the heat exchanger. The pump may include a flexible membrane as a reciprocating member. It may include a pneumatic actuation system that provides alternating positive and negative pressures to the membrane. Pumps having any of the various configurations described herein may be used in these methods.

[0085] One method of warming blood extracorporeally includes providing a reciprocating positive displacement pump having a curved rigid chamber wall, a flexible membrane and a flexible membrane attached to the rigid chamber wall such that the rigid chamber wall defines a pumping chamber, an inlet that directs flow through the rigid chamber wall into the pumping chamber substantially tangential to the rigid chamber wall, and an outlet that directs flow through the rigid chamber wall out of the pumping chamber substantially tangential to the rigid chamber wall; providing a warmer; supplying blood from a source; and pumping blood with the reciprocating positive displacement pump such that the blood flows through the warmer and is warmed. In certain embodiments, the reciprocating positive displacement pump has the structural features discussed herein.

[0086] Certain embodiments of these methods include monitoring a patient's temperature, which may include taking a temperature reading from a first location within the patient's body; taking a temperature reading from a second location within the patient's body; comparing the temperature readings from the first and second locations; issuing a first warning signal indicating an incorrect temperature reading if the temperature reading at the first location is not within a preset range of the temperature reading at the second location; determining whether the temperature reading from the first location is above a preset upper limit; and issuing a second warning signal indicating an overheating condition if the reading is above the preset upper limit.

[0087] The methods described herein may employ a disposable unit for use in a system for extracorporeal warming of blood. Such a disposable unit may include a reciprocating positive displacement pump having a curved rigid chamber wall, a flexible membrane attached to the rigid chamber wall such that the flexible membrane and the rigid chamber wall define a pumping chamber, an inlet for directing flow through the rigid chamber wall into the pumping chamber in a substantially tangential direction relative to the rigid chamber wall, and an outlet for directing flow through the rigid chamber wall out of the pumping chamber in a substantially tangential direction relative to the rigid chamber wall, and a heat exchanger component in fluid communication with the pump and adapted to be received in a warmer. The heat exchanger component may include a flexible bag defining a fluid path therethrough. The reciprocating positive displacement pump may have a structure described herein.

[0088] The disposable unit is preferably attachable in an easily removable manner to a base unit, which preferably includes means for attachment to a pneumatic actuation system that intermittently provides positive or negative pressure to the actuation chamber of the pump, and preferably includes a controller for controlling the pneumatic actuation system. The controller preferably controls the system to carry out the methods described herein. The base unit is preferably capable of receiving and holding disposable units having pod pumps with different pumping volumes.

[0089] In one embodiment of a system for extracorporeal thermal treatment, a heat exchanger is provided for warming blood; a reciprocating positive displacement pump having an inlet tube and an outlet tube for moving blood between a patient access device (e.g., a cannula, needle, or shunt) and the heat exchanger for warming the blood is provided; a first valve is provided in the inlet tube for preventing the flow of blood out of the pump; and a second valve is provided in the outlet tube for preventing the flow of blood into the pump. The pump may have a structure as described herein.

[0090] In certain embodiments, the reciprocating positive displacement pump uses a flexible membrane made of a material that reduces the membrane's popping movement as it reciprocates. The central portion may include a bump that spaces the central portion of the membrane away from the rigid chamber wall when the membrane is in a minimum pumping chamber volume position. Such a bump prevents fluid from becoming trapped between the membrane and the wall.

[0091] In one particular embodiment, the controller receives temperatures from a first temperature sensor located at the inlet that measures the temperature of blood entering the heat exchanger, and a second temperature sensor located at the outlet that measures the temperature of blood leaving the heat exchanger, while receiving flow information from a measurement system that measures the flow rate of blood passing through the heat exchanger. These temperature sensors may be located in a base unit of the system, while a thermally conductive thermowell in the disposable unit provides communication between the flow path and the sensor in the base unit. The controller also communicates with the electrical-to-thermal converter and receives information regarding the amount of power being used by the converter. In this embodiment, the controller analyzes the information received from the temperature probe, the measurement system, and the converter to determine if a fault condition exists, and issues a signal if a fault condition is detected.

[0092] The controller further receives temperature information from a temperature sensor mounted near the heating element near the heating plate of the heat exchanger. In this case, the electric current causes the heating element to heat the heating plate, which in turn heats the blood passing through the heat exchanger. A set of heating elements may overlap the flow path through the heat exchanger. The set of heating elements may include at least a first and a second heating element, with the second heating element located near the flow path near the outlet and the first heating element located near the flow path at a point upstream of the second heating element. A first temperature sensor is located near the flow path upstream of the first heating element. A second temperature sensor is located near the flow path between the first and second heating elements. In this embodiment, the controller receives temperature information from the first and second temperature sensors and issues a signal when the temperature difference measured by the first and second sensors exceeds a limit. Of course, the heat exchanger may use additional heating elements in addition to the two heating elements described here. The flow path may pass through a substantially planar disposable unit. As mentioned above, the heat exchanger may be a flexible bag.

[0093] A first heating plate, which in one embodiment is simply a thermally conductive plate, may be located between the heating element and the disposable unit. A second thermally conductive plate may be located opposite the first thermally conductive plate and adjacent the disposable unit. A second set of heating elements including at least a fourth, fifth and sixth heating element may be located on the opposite side of the second plate from the disposable unit and overlap the flow path, with the sixth heating element adjacent the flow path near the outlet, the fifth heating element adjacent the flow path preceding the sixth heating element, and the fourth heating element adjacent the flow path preceding the fifth heating element. In this embodiment, a third temperature sensor may be located adjacent the flow path between the fourth and fifth heating elements, and a fourth temperature sensor may be located adjacent the flow path between the fifth and sixth heating elements. The controller further receives temperature information from the third and fourth temperature sensors and issues a signal if the temperature difference measured by the third and fourth sensors exceeds a limit. In one embodiment, the first and second plates may be adapted to urge against one another upon actuation by the controller to force blood out of the disposable device.

[0094] In certain embodiments, the thermowells mentioned above may also be electrically conductive and used to detect leaks or air in the system. The disposable unit adapted to be received in the heat exchanger and containing the blood flow path may be made primarily of a thermoplastic material. The thermowells located at the inlet and outlet respectively are preferably metallic to improve thermal and electrical conductivity between the first temperature sensor and the blood in the inlet and between the second temperature sensor and the blood in the outlet. Typically, each warming plate includes a conductivity sensor that measures the resistance between the thermowell and the plate. The controller communicates with the conductivity sensor and issues a signal if the measured resistance is too low (indicating a leak in the disposable unit) and / or too high (indicating air in the disposable unit).

[0095] In certain embodiments, a valve system is provided. The valve system includes a valve cassette and a control cassette. The valve cassette contains a plurality of valves, each valve including a valve chamber and an actuation chamber, each valve actuable by a control fluid in the actuation chamber. The control cassette has a plurality of fluid interface ports providing fluid communication with the control fluid from a base unit. A plurality of tubes extend between the pump cassette and the control cassette. Each tube provides fluid communication between one of the fluid interface ports and at least one of the actuation chambers such that the base unit can actuate one of the valves by pressurizing the control fluid in one of the fluid interface ports.

[0096] These aspects of the invention are not meant to be exclusive or comprehensive, and other features, aspects, and advantages of the invention are possible and will become readily apparent to those of ordinary skill in the art when read in conjunction with the following description, the appended claims, and the accompanying drawings.

[0097] The above features of the present invention will be readily understood by reference to the following detailed description taken in conjunction with the accompanying drawings, in which:

[0098] It should be noted that the accompanying drawings and the elements illustrated therein are not necessarily drawn to scale or to scale, and like elements are numbered the same unless the context suggests otherwise. [Brief description of the drawings]

[0099] [Figure 1] FIG. 1 is a perspective view of an extracorporeal blood warming system having a base unit with a disposable unit, according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a perspective view of the components of the disposable unit shown in FIG. 1. [Diagram 3] FIG. 3 is a perspective view of a pump pod of the disposable unit shown in FIG. 2. [Figure 4] FIG. 4 is a schematic diagram illustrating a pressure actuation system that may be used to actuate the pump pod shown in FIG. 3. [Figure 5A] 11 is a top perspective view of an alternative embodiment of a pump pod arrangement. FIG. [Figure 5B] 11 is a bottom perspective view of an alternative embodiment of a pump pod arrangement. FIG. [Figure 6] 1 is a schematic diagram of an embodiment of an extracorporeal blood warming system. [Figure 7] 1 is a graph illustrating how pressure measurements can be used to detect the end of a stroke in one embodiment. [Figure 8] 1 is a graph illustrating how pressure measurements can be used to detect the end of a stroke in one embodiment. [Figure 9] 4 illustrates how the pressure measurement signal is filtered by the system's controller. [Figure 10] 4 illustrates how the pressure measurement signal is filtered by the system's controller. [Figure 11] 13 is a graph showing pressure readings at each pump pod in a disposable unit and the results of filtering these readings. [Figure 12] 1 is a graph showing how pressure measurements are used to determine average pressure. [Figure 13A] FIG. 2 is a perspective view of components from the system of FIG. 1 used to transfer heat to blood. [Figure 13B] 2 and 49 in accordance with an exemplary embodiment of the present invention. [Figure 13C] 1, there is shown a thermowell according to an exemplary embodiment of the present invention that may be used in the manifolds of FIGS. 2, 49 and 13B. [Figure 14] FIG. 13 is an exploded view showing the basic components of a heat exchanger in an alternative embodiment. [Figure 15] FIG. 15 shows a top perspective view of a disposable unit heat exchanger bag for use in the heat exchanger shown in FIG. [Figure 16]FIG. 15 shows an end perspective view of a disposable unit heat exchanger bag for use in the heat exchanger shown in FIG. [Figure 17] FIG. 15 shows a plan view of a disposable unit heat exchanger bag for use in the heat exchanger shown in FIG. [Figure 18] 1 shows a preferred arrangement of temperature transducers in a heat exchanger. [Figure 19] 1 is a flow chart illustrating a method for checking a patient's temperature. [Figure 20] 13A-13C are cross-sectional views of a pod pump that may be incorporated into embodiments of the fluid control cassette. [Figure 21] 11A-11C are cross-sectional views of valves that may be incorporated into embodiments of the fluid-control cassette. [Figure 22A] A pump cassette incorporating two pump pods of the type shown in FIG. 20 and several valves of the type shown in FIG. 21 is shown, along with various fluid paths and other components, according to an exemplary embodiment of the invention. [Figure 22B] A pump cassette incorporating two pump pods of the type shown in FIG. 20 and several valves of the type shown in FIG. 21 is shown, along with various fluid paths and other components, according to an exemplary embodiment of the invention. [Diagram 23] 1 is a schematic diagram of a dual housing cassette arrangement according to one embodiment. [Figure 24] 1 is a schematic diagram of a whole body hyperthermia treatment system according to an exemplary embodiment of the present invention. [Diagram 25] 12 illustrates the base unit of FIG. 11 in accordance with an exemplary embodiment of the present invention. [Figure 26] 26 illustrates a close-up view of the manifold interface of FIG. 25 in accordance with an exemplary embodiment of the present invention. [Figure 27] 1 illustrates an exemplary user interface screen, according to an exemplary embodiment of the present invention. [Figure 28] 11 is a graph illustrating how pressure applied to a pump can be controlled to facilitate end-of-stroke detection in accordance with an exemplary embodiment of the present invention. [Figure 29]4 is a schematic diagram of circulating fluid flow within the pump pod shown in FIG. 3 according to an exemplary embodiment of the present invention. [Figure 30A] FIG. 2 is a top view of a modular pod pump. [Figure 30B] FIG. 2 is a cross-sectional view of a modular pod pump. [Figure 31A] FIG. 31C is a top view of a pod pump with separate inlet and outlet ports, with a cut line shown to show the view of FIG. 31B. [Figure 31B] FIG. 2 is a cross-sectional view of a pod pump with separate inlet and outlet ports. [Figure 32A] FIG. 1 is a top view of a pod pump with an insert into the working chamber. [Figure 32B] FIG. 1 is a cross-sectional view of a pod pump with an insert into an actuation chamber. [Figure 33A] FIG. 13 is a top view of a pod pump with a stacked construction. [Figure 33B] FIG. 1 is a cross-sectional view of a pod pump with a stacked construction. [Figure 34A] FIG. 13 is a top view of a pod pump with a stacked construction. [Figure 34B] FIG. 1 is a cross-sectional view of a pod pump with a stacked construction. [Figure 35A] FIG. 1 is an exploded depiction of a pod pump with a multi-piece housing. [Figure 35B] 1A-1C are pictorial views of various embodiments of a diaphragm. [Figure 35C] 1A-1C are pictorial views of various embodiments of a diaphragm. [Figure 35D] 1A-1C are pictorial views of various embodiments of a diaphragm. [Figure 35E] 1A-1C are pictorial views of various embodiments of a diaphragm. [Figure 36A] FIG. 2 is an assembled side view of a pod pump with a multi-piece housing. [Figure 36B] FIG. 2 is an assembled end view of a pod pump with a multi-piece housing. [Figure 36C]FIG. 1 is a close-up view of the ports of a pod pump with a multi-piece housing. [Figure 37] FIG. 1 is an exploded representation of a multi-part pod pump. [Figure 38A] FIG. 2 is a top view of a pod pump assembly with integral valve. [Figure 38B] FIG. 2 is a cross-sectional view of a pod pump assembly with an integral valve. [Figure 39] FIG. 2 is an exploded depiction of a pod pump assembly. [Figure 40A] FIG. 2 is a representation of two pieces of a multi-piece pod pump housing. [Figure 40B] FIG. 13 is a close-up depiction of an alignment feature on a part of a multi-piece pump housing. [Figure 41A] FIG. 2 is a pictorial cross-sectional view of a pod pump assembly with portions removed. [Figure 41B] FIG. 1 is a close-up depiction of the alignment and joining features on the pod pump housing. [Figure 42A] FIG. 2 is a depiction of a pod pump. [Figure 42B] FIG. 42B is a cross-sectional view of the pod pump shown in FIG. 42A. [Figure 42C] FIG. 2 is a depiction of a pod pump. [Fig.42D] FIG. 42D is a cross-sectional view of the pod pump shown in FIG. [Figure 43A] FIG. 2 is an exploded view of one embodiment of a pod pump cassette. [Figure 43B] 1 illustrates a cross-sectional view of one embodiment of a pod pump cassette. [Figure 43C] 1 illustrates a cross-sectional view of one embodiment of a pod pump cassette. [Figure 44A] FIG. 2 is a depiction of one embodiment of a pod pump cassette. [Figure 44B] FIG. 2 is a depiction of one embodiment of a pod pump cassette. [Diagram 45] 1 illustrates a localized thermochemotherapy treatment system according to an exemplary embodiment of the present invention. [Figure 46A]5 illustrates a top perspective view of a flexible membrane having a raised bump configuration that may be used in a pump pod, such as the pump pod of FIG. 4, according to an exemplary embodiment of the invention. [Figure 46B] 5 illustrates a bottom perspective view of a flexible membrane having a raised bump configuration that may be used in a pump pod, such as the pump pod of FIG. 4, according to an exemplary embodiment of the invention. [Figure 47A] 26 illustrates some of the internal components of the base unit of FIGS. 1 and 25, in accordance with an exemplary embodiment of the present invention. [Figure 47B] FIG. 26 illustrates a rear perspective view of the base unit of FIGS. 1 and 25 showing a patient interface according to an exemplary embodiment of the present invention. [Figure 48] 1 illustrates an exemplary disposable unit, according to an exemplary embodiment of the present invention. [Figure 49A] 3 illustrates a perspective rear view of the manifold of FIG. 2 in accordance with an exemplary embodiment of the present invention. [Figure 49B] 3 illustrates a perspective bottom view of the manifold of FIG. 2 in accordance with an exemplary embodiment of the present invention. [Figure 50A] An embodiment of the sensing device in which the thermowell is a continuation of the fluid conduit. [Figure 50B] An embodiment of the sensing device in which the thermowell is a continuation of the fluid conduit. [Figure 51A] 11 is an embodiment of the sensing device in which the thermowell is separate from the fluid conduit. [Figure 51B] 11 is an embodiment of the sensing device in which the thermowell is separate from the fluid conduit. [Figure 52A] 1 is an embodiment of a sensing device showing various lengths and widths of thermowells. [Figure 52B] 1 is an embodiment of a sensing device showing various lengths and widths of thermowells. [Figure 53] FIG. 2 is a depiction of a thermowell according to one embodiment of a sensing device. [Figure 54] FIG. 2 is a cross-sectional view of an exemplary embodiment of a thermowell. [Figure 55A] 1 illustrates a cross-sectional view of an embodiment of a thermowell having a non-uniform wall thickness. [Figure 55B] 1 illustrates a cross-sectional view of an embodiment of a thermowell having a non-uniform wall thickness. [Figure 56A] 1A-1D are cross-sectional views of various embodiments of a thermowell embedded in a fluid conduit. [Figure 56B] 1A-1D are cross-sectional views of various embodiments of a thermowell embedded in a fluid conduit. [Figure 56C] 1A-1D are cross-sectional views of various embodiments of a thermowell embedded in a fluid conduit. [Figure 56D] 1A-1D are cross-sectional views of various embodiments of a thermowell embedded in a fluid conduit. [Figure 56E] 1A-1D are cross-sectional views of various embodiments of a thermowell embedded in a fluid conduit. [Fig. 56F] 1A-1D are cross-sectional views of various embodiments of a thermowell embedded in a fluid conduit. [Figure 56G] 1A-1D are cross-sectional views of various embodiments of a thermowell embedded in a fluid conduit. [Fig. 56H] 1A-1D are cross-sectional views of various embodiments of a thermowell embedded in a fluid conduit. [Fig. 56I] 1A-1D are cross-sectional views of various embodiments of a thermowell embedded in a fluid conduit. [Fig. 56J] 1A-1D are cross-sectional views of various embodiments of a thermowell embedded in a fluid conduit. [Figure 56K] 1A-1D are cross-sectional views of various embodiments of a thermowell embedded in a fluid conduit. [Figure 56L] 1A-1D are cross-sectional views of various embodiments of a thermowell embedded in a fluid conduit. [Figure 56M] 1A-1D are cross-sectional views of various embodiments of a thermowell embedded in a fluid conduit. [Figure 56N] 1A-1D are cross-sectional views of various embodiments of a thermowell embedded in a fluid conduit. [Fig. 56O] 1A-1D are cross-sectional views of various embodiments of a thermowell embedded in a fluid conduit. [Figure 56P] 1A-1D are cross-sectional views of various embodiments of a thermowell embedded in a fluid conduit. [Figure 56Q]1A-1D are cross-sectional views of various embodiments of a thermowell embedded in a fluid conduit. [Figure 56R] 1A-1D are cross-sectional views of various embodiments of a thermowell embedded in a fluid conduit. [Fig. 56S] 1A-1D are cross-sectional views of various embodiments of a thermowell embedded in a fluid conduit. [Figure 57] FIG. 2 is a side cross-sectional view of one embodiment of a sensing probe. [Figure 58] FIG. 58 is an exploded view of the embodiment shown in FIG. [Figure 59] 11 is a cross-sectional view of an alternative embodiment of the tip of the sensing probe. [Figure 60A] 1 is an alternative embodiment of a sensing probe. [Figure 60B] 1 is an alternative embodiment of a sensing probe. [Figure 61] FIG. 13 is a side view of an alternative embodiment of the sensing probe. [Figure 62A] FIG. 2 is a cross-sectional view of a sensing probe coupled to a thermowell. [Figure 62B] 62B is an alternative embodiment of the sensing probe shown in FIG. 62A. [Figure 63A] FIG. 58 is a cross-sectional view of the sensing probe shown in FIG. 57 coupled to a thermowell. [Figure 63B] 63B is an alternative embodiment of the sensing probe shown in FIG. 63A. [Figure 64] FIG. 2 is a cross-sectional view of an exemplary embodiment of a sensor apparatus. [Figure 65] 13 shows an alternative embodiment of a sensing probe coupled to a thermowell. [Figure 66] FIG. 13 is a cross-sectional view of one embodiment of a sensing probe coupled to a thermowell and suspended by a spring. [Figure 67] 1 is a cross-sectional view of one embodiment of a sensing probe within a housing. [Figure 68] 1 is a cross-sectional view of one embodiment of a sensing probe within a housing. [Figure 69] 1 is a cross-sectional view of one embodiment of a sensing probe within a housing. [Figure 70]FIG. 2 is a side view of a fluid conduit containing two sensors. [Figure 71] 1 is a cross-sectional view of a fluid pipe equipped with a sensor device; [Figure 72] 3 illustrates one way in which the various components of the disposable unit of FIG. 2 are interconnected. [Figure 73A] 1 is a graphical representation of occlusion detection according to an exemplary embodiment of the present invention. [Figure 73B] 1 is a graphical representation of occlusion detection according to an exemplary embodiment of the present invention. [Fig. 74A] 1 shows plots of volumetric flow, pod volume and total resident flow for two pump pods according to an exemplary embodiment of the invention operating with a 0 degree phase relationship. [Fig. 74B] 1 shows plots of volumetric flow, pod volume and total resident flow for two pump pods operating in a 180 degree phase relationship according to an exemplary embodiment of the invention. [Fig. 74C] 1 shows plots of volumetric flow, pod volume and total holdup flow for two pump pods operating in a 90 degree phase relationship according to an exemplary embodiment of the invention. [Figure 75] 1 illustrates a radiator for use with a length of tubing according to an exemplary embodiment of the present invention. [Figure 76] 76 illustrates that a length of flexible tubing can be attached to the radiator of FIG. 75 in accordance with an exemplary embodiment of the present invention. [Figure 77] 76 illustrates a heat exchanger plate having guides for receiving the radiator of FIG. 75 according to an exemplary embodiment of the present invention. [Figure 78] 76 illustrates a heat exchanger plate having a cylindrical wall for receiving the radiator of FIG. 75 according to an exemplary embodiment of the present invention. [Figure 79] 76 illustrates a heat exchanger plate integral with a radiator of the type shown in FIG. 75 according to an exemplary embodiment of the present invention. [Figure 80] 1 illustrates a sealed radiator having fluid inlet and outlet ports according to an alternative embodiment of the present invention. [Figure 81]49 illustrates a variation of the disposable unit of FIG. 48 including a patient connection circuit having a sterile protective covering, according to an exemplary embodiment of the present invention. [Figure 82] 82 depicts the patient connection circuit of FIG. 81 with a portion of the tubing exposed from the sterile protective covering in accordance with an exemplary embodiment of the present invention. [Figure 83] 82 illustrates a variation of the disposable unit of FIG. 81 including yet another fluid delivery tube, according to an exemplary embodiment of the invention. [Figure 84] 1 illustrates a fluid circuit that may be used to provide localized hyperthermic chemotherapy treatment, according to an exemplary embodiment of the present invention. [Figure 85] 1 illustrates another fluid circuit including a balance chamber that may be used to provide localized thermochemotherapy treatment, according to an exemplary embodiment of the present invention. [Figure 86] 13 illustrates another fluid circuit including a balance chamber and a second pump that may be used to provide localized thermochemotherapy treatment, according to an exemplary embodiment of the present invention. [Figure 87] 1 illustrates a fluid circuit including an outflow valve that may be used to provide localized hyperthermic chemotherapy treatment, according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0100] Definitions. As used in this specification and the appended claims, the following terms shall have the meanings indicated below, unless the context requires otherwise. "Spheroid" means a three-dimensional shape that corresponds to an ellipse rotated about one of its major axes, i.e., the major or minor axis, and includes three-dimensional ovals, oblate and prolate spheroids, spheres, and shapes substantially equivalent thereto.

[0101] By "hemispheroid" is meant a three-dimensional shape that generally corresponds to approximately half of a spheroid.

[0102] "Spherical" means generally spherical.

[0103] "Semispherical" means generally hemispherical.

[0104] "Dithering" a valve means rapidly opening and closing the valve.

[0105] "Pneumatic" means using air or other gas to move a flexible membrane or other member.

[0106] "Substantially tangential" means at an angle of less than 75° to the tangent or, in the case of a flat wall, at an angle of less than 75° to the wall.

[0107] "Fluid" is intended to mean a substance, e.g., a liquid, that can be pumped through a flow tube. Blood is one example of a fluid.

[0108] "Impedance" shall mean any opposition to the flow of a fluid.

[0109] A "patient" includes a human or animal to which fluid is pumped, as part of a medical procedure or for other reasons.

[0110] A "subject medium" is any material, including fluids, solids, liquids, or gases, that is in contact with a sensing probe or a thermowell.

[0111] Various aspects of the present invention will now be described with reference to various exemplary embodiments, with headings added for convenience only and not to be construed as limiting the invention in any way.

[0112] 1. Exemplary Reciprocating Positive Displacement Pump Embodiments of the present invention generally relate to certain reciprocating positive displacement pumps (sometimes referred to hereinafter as "pods," "pump pods," or "pod pumps") that are used to pump fluids, such as biological fluids (e.g., blood or ascites), therapeutic fluids (e.g., drug solutions), or surfactant fluids. Certain embodiments are specifically configured to impart low shear and turbulence to the fluid as it is pumped from an inlet to an outlet. Such embodiments may be particularly useful when pumping fluids that may be damaged by such shear forces (e.g., blood, especially warm blood that is prone to hemolysis) or fluids that may be damaged by turbulent flow (e.g., surfactants or other fluids that may foam or become damaged or unstable in the presence of turbulent flow).

[0113] Generally, a pod pump is a modular pumping device. The pod pump can be connected to any source of subject fluid (i.e., liquid, gas, or variations thereof), including, but not limited to, a fluid line, a tube, or a fluid container, to effect movement of the subject fluid. In some embodiments, multiple pod pumps are used, while in other embodiments, a single pod pump is used. The pod pump can further be connected to at least one actuation source, which in some embodiments is at least one air chamber.

[0114] In some embodiments, the pod pump is modularly connected to any instrument or machine, but in other embodiments, the pod pump is part of an instrument, machine, or vessel that is attached to another instrument, machine, or vessel, and while the pod pump is modular, it may also be part of another modular structure that interacts with any machine, instrument, vessel, or otherwise.

[0115] In one embodiment, a pod pump includes a housing with a diaphragm or movable impermeable membrane attached thereto. The diaphragm creates two chambers. One chamber is not in contact with the subject fluid. This chamber is referred to as the "working chamber." The other chamber is in contact with the subject fluid. This chamber is referred to as the "pump chamber" or "pumping chamber."

[0116] In some embodiments, the pod pump includes an inlet fluid path and an outlet fluid path. Thus, in these embodiments, the fluid of interest is pumped into and out of the pump chamber. In some embodiments, a valving mechanism is used to ensure that the fluid flows in the intended direction. In other embodiments, the inlet and outlet fluid paths are the same.

[0117] Actuation of the diaphragm is brought about by a change in pressure. This change in pressure can be generated using positive and negative air pressure. In one embodiment, a pneumatic mechanism is used to fill the actuation chamber with air (generating positive pressure) and then suck the air out of the actuation chamber (generating negative pressure). In some embodiments, the air flows through a port in the actuation chamber. This port can be, but is not limited to, an opening or hole in the actuation chamber. In other embodiments, any fluid (i.e., liquid, gas, or variations thereof) can be used as the actuation fluid.

[0118] For purposes of explanation, exemplary embodiments are shown and described, however, other embodiments are contemplated and, therefore, the description provided is intended to facilitate an understanding of pod pump embodiments and other variations will become apparent.

[0119] 1.1. Exemplary Pump Pod Configurations FIG. 3 illustrates a reciprocating positive displacement pump 25 according to an exemplary embodiment of the present invention. In this embodiment, the reciprocating positive displacement pump 25 is essentially a self-contained unit (sometimes referred to hereinafter as a "pod") that may be used as one component of a larger pumping system. The reciprocating positive displacement pump 25 includes an "upper" portion (also referred to as a "pumping chamber wall") 31 and a "lower" portion (also referred to as a "working chamber wall") 32 that are joined at a pod wall 30, for example by ultrasonic welding or other techniques. Note that the terms "upper" and "lower" are relative and are used here for convenience with respect to the orientation shown in FIG. 3. Each of the portions 31 and 32 has a solid interior surface that is preferably (although not necessarily) hemispherical, such that the pod has a preferably (although not necessarily) spherical interior cavity.

[0120] 3, actuation chamber wall 32 is of unitary construction, while pumping chamber wall 31 is formed of two halves joined along perimeter 2052, for example by ultrasonic welding or other techniques (this facilitates assembly of the integral valve, discussed below). Figure 37 shows an exploded view of three pump pod wall sections in accordance with an exemplary embodiment of the invention. FIG. 38A shows a top view of the assembled three-piece pump pod. FIG. 38B shows a vertical cross-sectional view of the assembled three-piece pump pod. FIG. 39 shows an exploded view of the pump pod components. FIGS. 37-39 are discussed in more detail below. Of course, while ultrasonic welding of the pumping chamber wall 31 and the actuation chamber wall 32 is believed to be a preferred embodiment, the present invention is in no way limited to the manner in which the pumping chamber wall 31 and the actuation chamber wall 32 are constructed or assembled.

[0121] Inside the reciprocating positive displacement pump 25, a flexible membrane 33 (also referred to as the "pump diaphragm") is mounted where the pumping chamber wall 31 and the actuation chamber wall 32 meet (i.e., at the pod wall 30). The pump diaphragm 33 effectively divides the interior cavity into a variable volume pumping chamber (defined by the rigid interior surface of the pumping chamber wall 31 and the upper surface of the membrane 33) and a complementary variable volume actuation chamber (defined by the rigid interior surface of the actuation chamber wall 32 and the lower surface of the membrane 33). The upper portion 31 includes a fluid inlet 34 and a fluid outlet 37, both of which are in fluid communication with the pumping chamber. The lower portion 32 includes a gas pressure interface 38 in fluid communication with the actuation chamber. As discussed in more detail below, the membrane 33 can be moved back and forth within the cavity by applying alternating negative and positive gas pressures to the gas pressure interface 38. As membrane 33 shuttles back and forth in the embodiment shown in FIG. 3, the sum of the volumes of the pumping chamber and the actuation chamber remains constant.

[0122] During normal fluid pumping operation, application of a negative gas pressure to the gas pressure interface 38 tends to pull the membrane 33 toward the actuation chamber wall 32, expanding the pumping chamber and drawing fluid into the pumping chamber through the inlet 34. Meanwhile, application of a positive gas pressure to the gas pressure interface 38 tends to push the membrane 33 toward the pumping chamber wall 31, contracting the pumping chamber and expelling fluid therein through the outlet 37. During such pumping operation, the inner surfaces of the pumping chamber wall 31 and the actuation chamber wall 32 limit the movement of the membrane 33 as it moves back and forth. In the embodiment shown in FIG. 3, the inner surfaces of the pumping chamber wall 31 and the actuation chamber wall 32 are rigid, smooth, and hemispherical. Instead of a rigid actuation chamber wall 32, an alternative rigid limiting structure, such as a portion of the bezel used to supply the gas pressure and / or a set of ribs, may be used to limit the movement of the membrane as the pumping chamber approaches its maximum value. The structure of the bezel and ribs is generally described in U.S. patent application Ser. No. 10 / 697,450, entitled "BEZEL ASSEMBLY FOR PNEUMATIC CONTROL," filed Oct. 30, 2003, published U.S. Patent Application Publication No. 2005 / 0095154 (Attorney Docket No. 1062 / D75), and related International Application No. PCT / US2004 / 035952, entitled "BEZEL ASSEMBLY FOR PNEUMATIC CONTROL," filed Oct. 29, 2004, published WO 2005 / 044435 (Attorney Docket No. 1062 / D71WO), both of which are incorporated herein by reference in their entireties. Thus, a rigid limiting structure, such as a rigid actuation chamber wall 32, a bezel or a set of ribs, defines the shape of the membrane 33 when the pumping chamber is at its maximum. In a preferred embodiment, the membrane 33 (when pressed against the rigid limiting structure) and the rigid inner surface of the pumping chamber wall 31 define a spherical pumping chamber volume when the pumping chamber volume is at its maximum.

[0123] 3, the movement of membrane 33 is limited by pumping chamber wall 31 and actuation chamber wall 32. As long as the positive or negative overpressure supplied through gas pressure port 38 is strong enough, membrane 33 will move from a position limited by actuation chamber wall 32 to a position limited by pumping chamber wall 31. When the membrane is pressed against actuation chamber wall 32, the membrane and pumping chamber wall 31 define a maximum volume of the pumping chamber. When the membrane is pressed against pumping chamber wall 31, the volume of the pumping chamber is minimum.

[0124] In a preferred embodiment, both pumping chamber wall 31 and working chamber wall 32 have a semi-spheroidal shape such that the pumping chamber has a spheroidal shape when the pumping chamber volume is at its maximum. More preferably, both pumping chamber wall 31 and working chamber wall 32 have a hemispheroidal shape such that the pumping chamber has a spherical shape when the pumping chamber volume is at its maximum. By using a pumping chamber that has a spheroidal shape, particularly a spherical shape, at its maximum volume, circulatory flow can be achieved throughout the pumping chamber. Such a shape tends to prevent stagnant fluid regions within the pumping chamber. As discussed in more detail below, the orientation of inlet 34 and outlet 37, each of which is substantially tangential to the inner surface of pumping chamber wall 31, also tends to promote circulation of fluid in the pumping chamber and reduce the likelihood of stagnant fluid regions forming. Additionally, compared to other volumetric shapes, a spherical shape (and generally a spheroidal shape) creates less shear and turbulence as fluid enters, circulates through, and exits the pumping chamber.

[0125] 1.2. Example Inlet / Outlet Valves Generally, reciprocating positive displacement pumps of the above types may include or be used with various valves to control fluid flow through the pump. Thus, for example, a reciprocating positive displacement pump may include or be used with an inlet valve and / or an outlet valve. The valves may be passive or active. In the exemplary embodiment shown in FIG. 3, the reciprocating positive displacement pump 25 includes a passive one-way inlet check valve 35 and a passive one-way outlet check valve 36. The inlet check valve 35 allows fluid to be drawn into the pumping chamber through the inlet 34, but substantially prevents backflow at the inlet 34. The outlet check valve 36 allows fluid to be pumped from the pumping chamber through the outlet 37, but substantially prevents backflow at the outlet 37.

[0126] Thus, in an exemplary embodiment using reciprocating positive displacement pump 25, membrane 33 is pushed back and forth by positive or negative pressurization of gas supplied through gas pressure port 38, which connects the actuation chamber to a pressure actuation system. The resulting reciprocating motion of membrane 33 draws liquid from inlet 34 into the pumping chamber (outlet check valve 36 prevents liquid from being sucked back into the pumping chamber through outlet 37) and pushes liquid out of the pumping chamber through outlet 37 (inlet check valve 35 prevents liquid from being pushed back into inlet 34).

[0127] In alternative embodiments, active valves may be used in place of the passive check valves 35 and 36. The active valves may be actuated by the controller in a manner that directs flow in a desired direction. Generally, such an arrangement allows the controller to effect flow in both directions through the pump pod 25. In a typical system, flow is normally in a first direction, e.g., from the inlet to the outlet. In some cases, flow may be directed in the opposite direction, e.g., from the outlet to the inlet. Such flow reversal may be used, for example, while priming the pump, to check for abnormal tubing conditions (e.g., tubing blockages, occlusions, dislodgments, or leaks), or to remedy abnormal tubing conditions (e.g., to try to remove blockages).

[0128] 1.3. Example Pump Inlet / Outlet Orientations 3, inlet 34 and outlet 37 are oriented to direct fluid into and out of the pumping chamber at a substantially tangential angle relative to the interior surface of pumping chamber wall 31. Thus, fluid entering the pumping chamber through inlet 34 is prevented from being perpendicular to membrane 33 as the membrane approaches the location where the pumping chamber volume is at its maximum. This orientation of the inlet 34 and outlet 37 tends to reduce shear forces on the pumped liquid as compared to centrifugal pumps, which typically impose significant stresses on the pumped fluid.

[0129] The orientation of the inlet 34 and outlet 37 relative to each other also tends to reduce shear flow and turbulence. When the pumping chamber reaches maximum volume, the fluid continues to circulate within the pumping chamber even though it stops flowing through the inlet 34. The direction of this circulating flow is a result of the orientation of the inlet 34 and the internal flow regime. Typically, after a very short pause, the membrane 33 is actuated and begins to move to reduce the volume of the pumping chamber and the fluid begins to flow through the outlet 37. As the fluid enters the pumping chamber, it flows in a rotating flow and continues to rotate until it exits the pumping chamber. The fluid exiting the pumping chamber peels off from the outer layer of the rotating flow in the same direction that the fluid is rotating. The spherical shape of the pump pod is particularly well-suited to achieving the desired circulating flow. The orientation of the outlet 37 relative to the circulating flow within the pumping chamber at maximum pumping chamber volume is such that the flow does not have to change direction at a sharp angle as it begins to be forced out through the outlet 37. By avoiding a sharp change in flow direction, shear and turbulence are reduced. Thus, the orientation of the inlet 34 and outlet 37 relative to one another and the internal flow configuration reduce shear and turbulence to the liquid being pumped. For example, in Figure 3, there is only a slight change in direction of the flow path extending directly from the inlet 34 to the outlet 37, although other arrangements can reduce the sharp change in direction as the pump pod transitions from a fill stroke to a discharge stroke.

[0130] Thus, when the fluid being pumped is whole blood, centrifugal pumps (which apply substantial stress to red blood cells) tend to cause significant hemolysis and thus a reduction in the patient's hematocrit to the patient's detriment, whereas pump pods of the above types (which apply low shear and turbulence) tend to cause substantially less hemolysis. Similarly, when the fluid being pumped is a surfactant or other fluid that tends to foam, the low shear and low turbulence of the pod pumps tend to reduce foaming.

[0131] 29 is a schematic diagram of a circulating fluid flow within pump pod 25 shown in FIG. 3 according to an exemplary embodiment of the invention. As the fluid enters the pumping chamber through the inlet, the orientation of the inlet directs the fluid tangentially to the inner surface of the pumping chamber wall to create a circulating flow. As the fluid approaches the outlet, it is already flowing substantially toward the outlet so that it does not have to suddenly change direction when it is pumped out of the outlet. Thus, the fluid delaminates from the circulating flow, subjecting the fluid to low shear forces.

[0132] Generally, for low shear and / or low turbulence applications, it is desirable for the inlets and outlets to be configured to avoid sharp or abrupt changes in fluid direction. Additionally, it is generally desirable for the inlets and outlets (and the pump chamber itself) to be free of burrs. The inlet and / or outlet may include curved edges to promote smooth exit of the fluid flow.

[0133] 1.4. Alternative Pump Configurations 20 is a cross-sectional view of an alternative pump pod 2025 that may be incorporated, for example, into a larger fluid-control cassette, according to an alternative embodiment of the present invention. In this embodiment, the pump pod is formed from three rigid components: an "upper" plate 2091, a middle plate 2092, and a "lower" plate 2093 (note that the terms "upper" and "lower" are relative and are used here for convenience with respect to the orientation shown in FIG. 20). The upper and lower plates 2091, 2093 may be flat on both sides, while the middle plate 2092 includes passages, recesses, and holes that define various fluid paths, chambers, and ports. To form the pump pod 2025, the upper and lower plates 2091, 2093 may include generally hemispheroidal portions that together define hemispheroidal chambers.

[0134] A membrane 2109 divides the central cavity of the pump pod into a chamber that receives the fluid to be pumped (the pumping chamber) and another chamber that receives a control gas that actuates the pump by gas pressure (the actuation chamber). An inlet 2094 allows fluid to enter the pumping chamber, and an outlet 2095 allows fluid to exit the pumping chamber. The inlet 2094 and outlet 2095 may be formed between the middle plate 2092 and the bottom plate 2093. Gas pressure is supplied through gas pressure port 2106 to either push the membrane 2109 against one wall of the pump pod cavity, minimizing the volume of the pumping chamber (as shown in FIG. 20), or to pull the membrane toward the other wall of the pump pod cavity, maximizing the volume of the pumping chamber, by positive gas pressure (as shown in FIG. 20), or negative gas pressure (as shown in FIG. 20).

[0135] The membrane 2109 has a thickened periphery 2088 which is held tightly in a groove 2089 in the middle plate 2092. Thus, the membrane 2109 can be placed and held in the groove 2089 before the top plate 2091 is ultrasonically welded to the middle plate 2092 so that the membrane does not interfere with ultrasonically welding the two plates together and is not dependent on the two plates being ultrasonically welded to hold the membrane correctly in place. This pump pod can therefore be easily manufactured without relying on ultrasonic welding, which must be performed to very tight tolerances.

[0136] One or more pump pods 2025 may be incorporated into a single cassette, which may also include one or more valves 2000. Figure 21 is a cross-sectional view of a pneumatically controlled valve 2000 that may be used in the cassette embodiments described above. A membrane 2090 defines a valve actuation chamber 2097 in conjunction with a middle plate 2092. Gas pressure is provided through a pneumatic pressure port 2096 to either force the membrane 2090 against a valve seat 2099 to close the valve, or to force the membrane away from the valve seat to open the valve, using positive gas pressure. A control gas chamber 2098 is defined by the membrane 2090, the top plate 2091, and the middle plate 2092. The middle plate 2092 is recessed into which the membrane 2090 is positioned to define a control gas chamber 2098 on one side of the membrane and a valve actuation chamber 2097 on the other side.

[0137] Pneumatic ports 2096 are defined by passages formed in the "top" surface of middle plate 2092 and top plate 2091. By fluidly connecting several valve train chambers in a cassette, the valves can be ganged so that all ganged valves can be opened and closed simultaneously by a single source of pneumatic pressure. Passages formed in the "bottom" surface of middle plate 2092 and the bottom plate define valve inlets 2094 and valve outlets 2095. Holes through middle plate 2092 provide communication between inlets 2094 and valve train chambers 2097 (through valve seats 2099), and between the valve train chambers and outlets 2095.

[0138] The membrane 2090 has a thickened periphery 2088 that fits closely into a groove 2089 in the middle plate 2092. Thus, the membrane 2090 can be placed and held in the groove 2088 before the top plate 2091 is ultrasonically welded to the middle plate 2092, so that the membrane does not interfere with ultrasonic welding of the two plates, and furthermore, the membrane is not relied upon to be held correctly in place during ultrasonic welding. Thus, the valve can be easily manufactured without relying on ultrasonic welding, which must be performed with very strict precision. As shown in FIG. 21, the top plate 2091 may include an additional portion that extends into the controlled gas chamber 2098 to prevent the membrane 2090 from being pushed too far away from the groove 2089, causing the membrane's thickened periphery 2088 to pop out of the groove 2089.

[0139] 30A and 30B, one embodiment of a pod pump 3000 is shown. In this embodiment, the pod pump 3000 includes a housing. With reference to FIG. 30B, the housing includes two portions 3002, 3004. The portions 3002, 3004 are joined together and hold a diaphragm 3006. With reference to FIG. 30A, as shown in this embodiment, the housing portions 3002, 3004 are joined together with threads. However, in alternative embodiments, any fastener or fastening method can be used, including but not limited to snap tabs, ultrasonic welding, laser welding, or other assembly means known in the art.

[0140] As shown in the embodiment of Figures 30A and 30B, the housing is formed from two parts 3002, 3004, however, in other embodiments (some of which are described below) the housing is formed from three or more parts. In yet other embodiments, the housing is a single part.

[0141] The housing may vary in size in different embodiments. The size may vary depending on the volume of target fluid to be pumped with each stroke of the pod pump. Another factor that may affect the size is the desired aspect ratio of the pod pump.

[0142] Additionally, depending on the embodiment, the shape of the housing chamber may vary. Thus, while Figures 30A and 30B, and many other figures in this description, describe and show a substantially spherical pod pump housing, the pod pump housing is by no means limited to a spherical shape. With reference to Figures 42A and 42B, alternative pod pump 4200 shapes are shown. Thus, although only two shapes are shown herein, in alternative embodiments the pod pump housing can be any desired shape.

[0143] 42A and 42B, alternative embodiments of the pod pump are shown. In this embodiment, the pod pump has an oval shape, however, in further embodiments, the pod pump can have any desired shape. Many of the pod pump embodiments have a pump chamber, an actuation chamber, a diaphragm (or movable member), at least one actuation port, and at least one inlet / outlet port. In some embodiments, the pod pump has an inlet port and an outlet port. Various embodiments are described herein, and it is understood that features described with respect to one embodiment may be utilized in any of the embodiments, and thus features of the embodiments may be combined in various different ways, and any of the embodiments may include one or more of the features described herein.

[0144] 30A and 30B, the pod pump shown in this embodiment is substantially spherical. As shown in this embodiment, the pump housing (including the pump chamber and the working chamber) is substantially spherical, however, the peripheral flange or feature of the pump housing is not perfectly spherical. Thus, the exterior shape of the housing can be any shape, and in some embodiments, the exterior shape of the housing is different in shape than the pump housing. However, in some embodiments, the outer housing is the same or substantially the same shape as the pump housing.

[0145] The housing portions 3002, 3004 when joined form a hollow chamber. In embodiments where the housing is a single piece, the interior of the housing is the hollow chamber. When the diaphragm 3006 is connected or attached to the interior of the housing, the diaphragm 3006 divides the interior of the housing into two chambers: an actuation chamber 3010 and a pump chamber 3012. In some embodiments, the interior of the housing is divided into two chambers of equal volume, while in other embodiments the two chambers are of unequal volume.

[0146] The diaphragm 3006 may be made of any flexible material having the desired durability and compatibility with the fluid of interest. The diaphragm 3006 may be made of any material that can deflect in response to liquid or gas pressure or vacuum applied to the actuation chamber 3010. The diaphragm material may be selected for biocompatibility, temperature compatibility, or compatibility with various subject fluids that may be pumped by the diaphragm 3006 or introduced into the chamber to facilitate movement of the diaphragm 3006. In this exemplary embodiment, the diaphragm 3006 is made from high elongation silicone. However, in other embodiments, the diaphragm 3006 is made from any elastomer or rubber, including but not limited to silicone, urethane, nitrile, EPDM (Ethylene Propylene Diene Methylene Linkage), or any other rubber or elastomer.

[0147] The shape of the diaphragm 3006 is determined by many variables, including but not limited to: the shape of the chamber, the size of the chamber, the characteristics of the target fluid, the volume of the target fluid pumped per stroke, and the means or manner of attachment of the diaphragm 3006 to the housing. The size of the diaphragm 3006 is determined by many variables. These variables include, but are not limited to, the shape of the chamber, the size of the chamber, the characteristics of the target fluid, the volume of the target fluid pumped per stroke, and the means or manner of attachment of the diaphragm 3006 to the housing. Thus, depending on these and other variables, different embodiments may have different shapes and sizes of the diaphragm 3006.

[0148] The diaphragm 3006 can be of any thickness. However, in some embodiments, the thickness ranges from 0.002 inches to 0.125 inches. The desired thickness may vary depending on the material used for the diaphragm. In one embodiment, a high elongation silicone is used that is 0.015 inches to 0.050 inches thick.

[0149] In this exemplary embodiment, the diaphragm 3006 is preformed to include a substantially dome-shaped shape in at least a portion of the area of ​​the diaphragm 3006. One embodiment of a dome-shaped diaphragm 3006 is shown as 3514 in FIG. 35A. Again, the dimensions of the dome may vary based on some of the variables listed above, or other variables. However, in other embodiments, the diaphragm 3006 may not include a preformed dome shape.

[0150] In the present exemplary embodiment, the dome of the diaphragm 3006 is formed using compression molding, however, in other embodiments, the dome may be formed using injection molding.

[0151] In an alternative embodiment, the diaphragm 3006 is substantially flat until actuated. In other embodiments, the size, width or height of the dome may vary.

[0152] In various embodiments, the diaphragm 3006 may be held in place by various means and methods. In one embodiment, the diaphragm 3006 is crimped between portions of the housing, and in some of these embodiments, the periphery of the housing may include a mechanism for gripping the diaphragm 3006. In another version of this embodiment, the diaphragm 3006 is crimped to the housing using at least one bolt or other device. In another embodiment, the diaphragm 3006 is overmolded with a plastic piece that is welded or otherwise attached to the housing. In another embodiment, the diaphragm is affixed to the intermediate portion (not shown, described below with respect to FIGS. 33A-34B) and the actuation housing portion. Although certain embodiments have been described for attaching the diaphragm 3006 to the housing, any method or means of attaching the diaphragm 3006 to the housing may be used. In an alternative embodiment, the diaphragm 3006 is attached directly to one of the housing portions at attachment point 3018.

[0153] In the embodiment shown in FIG. 30B, the diaphragm 3006 is held in place inside the housing at the attachment point 3018 using one or another of the attachment methods of the above embodiments. The attachment point 3018 is the area where the two housing parts 3002, 3004 meet and the diaphragm 3006 is held between the two parts 3002, 3004. In some embodiments, the diaphragm 3006 is thicker at the attachment point 3018 than in other areas. In some embodiments, the thicker area is a gasket, in some embodiments an o-ring, ring, or any other form of gasket. Referring to FIG. 35A, an embodiment of a diaphragm 3514 with a gasket 3520 is shown. In these embodiments, the gasket 3520 is where it connects to the housing.

[0154] In some embodiments of the gasket 3520, the gasket 3520 is continuous with the diaphragm 3514. However, in other embodiments, the gasket 3520 is separate from the diaphragm 3514. In some embodiments, the gasket 3520 is made of the same material as the diaphragm 3514. However, in other embodiments, the gasket 3520 is made of a different material than the diaphragm 3514. In some embodiments, the gasket 3520 is formed by overmolding a ring around the diaphragm 3514. The gasket 3520 can be any shape ring or seal desired to complement an embodiment of the pod pump housing. In some embodiments, the gasket 3520 is a compression type gasket.

[0155] The interior of the housing includes at least one port for a subject fluid (a pump port) and at least one port for an actuation fluid (an actuation port). Referring to Figure 30B, an actuation port 3008 and a pump port 3014 are shown. While the embodiment shown in Figure 30B includes one pump port 3014 and one actuation port 3008, in other embodiments (some of which are described below), the pod pump includes two or more pump ports and / or two or more actuation ports.

[0156] 30B, the locations of the pump port 3014 and actuation port 3008 may vary depending on the embodiment. In the illustrated embodiment, the pump port 3014 and actuation port 3008 are located on one side of the pod pump 3000. In other embodiments, some of which are shown and described herein, the pump port and actuation port are in various locations on the pod pump, some on the same side, some on different sides, and in embodiments having more than one pump port and / or more than one actuation port, the locations of these ports may all be different. However, in most embodiments, the actuation port (or at least one actuation port in some embodiments) 3008 is in fluid communication with the actuation chamber 3010, and the pump port (or at least one pump port in some embodiments) 3014 is in fluid communication with the pump chamber 3012.

[0157] The actuation port 3008 communicates liquid or gas pressure with a source of liquid or gas to add or remove liquid or gas from the actuation chamber 3010 . Upon addition or removal of liquid or gas to or from the actuation chamber 3010, the diaphragm 3006 deflects to increase or decrease the volume of the pumping chamber 3012. This deflecting action of the diaphragm 3006 causes the subject fluid to move into or out of the pump port 3014. In the embodiment shown in FIG. 30B, both the actuation port 3008 and the pumping port 3014 are in line for attachment or detachment to other equipment. However, as discussed above, these ports may be oriented in any desired manner.

[0158] 30B, in the illustrated embodiment, O-rings 3020 are located at the actuation port 3008 and the pumping port 3014. However, in other embodiments, other means of connecting the pod pump 3000 to other equipment may be used, such as barbed connectors, quick connects, adhesives, clamps, and other fastening means. With reference to FIG. 30A, in one embodiment, flexible tabs 3016 are provided to facilitate fastening the pod pump 3000 to other equipment, however, in alternative embodiments, additional or different positioning and fastening mechanisms or means may be used. In yet another embodiment, a fastening mechanism may not be present on the pod pump 3000.

[0159] The movement of the diaphragm 3006 changes the volume of the pump chamber 3012 and the volume of the actuation chamber 3010. As the volume of the actuation chamber 3010 decreases, the volume of the pump chamber 3012 increases. This creates a negative pressure in the pump chamber 3012. This negative pressure causes the subject fluid to flow into the pump chamber 3012.

[0160] When positive pressure is created in the actuation chamber 3010 by air or liquid entering the actuation chamber 3010 through one or more actuation ports 3008, the volume of the pump chamber 3012 decreases, creating a positive pressure in the pump chamber 3012. This positive pressure pushes the subject fluid out of the pump chamber 3012 and through one or more pump ports 3014. While one pump port 3014 is shown, other embodiments include two or more pump ports. In some of these embodiments, one of the pump ports is an inlet port and one of the pump ports is an outlet port. The location, position, and configuration of the pump ports will or may vary depending on the particular intended purpose.

[0161] 31A and 31B, another embodiment of a pod pump 3100 is shown. In this embodiment, the housing includes two portions 3102, 3104. Referring to FIG. 31B, a diaphragm 3106 is connected to the interior chamber of the housing at point 3116. In this embodiment, the diaphragm 3106 is connected to the housing where the two portions 3102, 3104 meet, thereby sandwiching the diaphragm 3106 and holding it there.

[0162] The diaphragm 3106 divides the interior of the pod pump 3100 housing into two chambers: an actuation chamber 3108 and a pump chamber 3110. In this embodiment, the pump chamber 3110 includes two pump ports 3114, either of which may be the inlet or outlet port when the pump is actuated. Referring again to FIGS. 31A and 31B, the pod pump 3100 includes barb connectors 3112 that may be used to attach tubing to the pump ports 3114 and the actuation port 3118. The role of each port is determined by the configuration of other equipment to which it is attached. In this embodiment, barb connectors 3112 are provided for attachment of tubing, although other attachment methods are possible.

[0163] 32A and 32B, an alternative embodiment of a pod pump 3000 is shown that is similar to the pod pump shown in FIGS. 30A and 30B, except that in this embodiment, the actuation chamber 3108 includes an additional component 3202. In some embodiments, the pump chamber 3110 may also include the additional component 3202, while in other embodiments, only the pump chamber may include the additional component 3202. The additional component 3202 may act to limit the movement of the diaphragm 3006, dampen the movement of the diaphragm 3006, filter air or gas entering or leaving the actuation chamber 3108, or dampen sound or vibration within the pod pump 3000. For example, in some embodiments where the pod pump 3000 is used in a fluid management system, the additional component 3202 may be present in both chambers to reduce the time it takes to equalize temperatures in both chambers. In some of these embodiments, each additional component 3202 may include a reticulated plastic, a woven type material, copper wool, a foam material, or other material, and may provide a large surface area for air or other gas equilibration. In some embodiments, each additional component 3202 may be part of a fluid management system (FMS) and may be used to perform certain measurements of the fluid management system, such as measuring the volume of a target fluid pumped through a pump chamber during one stroke of the diaphragm 3006 or detecting air in the pumping chamber, using techniques such as those described in U.S. Patent Nos. 4,808,161, 4,826,482, 4,976,162, 5,088,515, and 5,350,357, which are incorporated herein by reference in their entirety. The additional component 3202 may completely or partially cover the actuation chamber port, or may be completely separate from the actuation chamber port.

[0164] In the figures presented thus far, various embodiments, features, and characteristics of the pod pump have been described and illustrated. The various features may be combined in various ways, i.e., any feature may be added to any embodiment of the pod pump. The illustrated configurations are for illustrative purposes only, and the location of ports, number of ports, attachment means, housing size, chamber size, etc. may vary from embodiment to embodiment. The figures and embodiments described below further include various embodiments, features, and characteristics, all of which may be "combined in various ways" with any of the features and characteristics described in the embodiments described herein.

[0165] 33A and 33B, an alternative embodiment of a pod pump 3300 is shown, including a pump chamber cover 3302, an actuation chamber cover 3304, and a mid-plate portion 3306. In this embodiment, the mid-plate 3306 and actuation chamber cover 3304 carry a diaphragm 3308 and one or more secondary diaphragms 3310 or 3312. The secondary diaphragms may operate passively or may function as active valves actuated by gas, liquid, or mechanical forces to control fluid flow through the pump chamber cover fluid passage 3314. In this embodiment of the pod pump 3300, a fluid passage 3314 is formed in the pump chamber cover 3302 such that fluid will flow through the passage 3314 regardless of the position of the diaphragm 3308. In this embodiment as well as other embodiments, the pump chamber cover 3302, actuation chamber cover 3304, and mid-plate 3306 are made of plastic in one embodiment, but may be made of other materials including, but not limited to, metal or glass in other embodiments. In this embodiment, the pump chamber cover 3302, actuation chamber cover 3304 and middle plate 3306 may be laser welded together or may be joined by a variety of other methods deemed appropriate for the component materials selected and the desired pod pump application, including but not limited to snap tabs, press fits, snap fits, solvent bonding, heat welding, electromagnetic welding, resistance welding, RF welding, screws, bolts, ultrasonic welding, adhesives, crimping with components that contact the pump during use, or other joining methods commonly used in the art.

[0166] 34A and 34B, one embodiment of a pod pump 3400 is shown. In this embodiment, the inlet and outlet ports are located at opposite ends of the pump chamber 3406 and can be used as either depending on the configuration or intended use of the pump. The diaphragm 3408 is shown almost fully extending into the pump chamber 3406. In this embodiment, the inlet and outlet ports 3402, 3404 may be partially or fully blocked by the diaphragm 3408 when the diaphragm 3408 is fully actuated by fluid pressure in the actuation chamber 3410. Closing the inlet or outlet ports may function to restrict or redirect the flow of a subject fluid through the pump chamber 3406, as may be desired in certain applications. In this embodiment, the pumping side of the diaphragm 3408, i.e., the side of the diaphragm 3408 that contacts the target fluid, is smooth, which may provide different flow characteristics for some target fluids when the diaphragm is fully inserted into the pump chamber 3406, or may provide a different contact condition between the diaphragm 3408 and the pump chamber 3406 when a reduction in flow rate through the inlet or outlet ports 3402, 3404 is desired.

[0167] In some embodiments, as shown in FIG. 34B, the diaphragm does not have a uniform cross-sectional thickness. Diaphragms of thin, thick or non-uniform thickness may be used to tailor the strength, bending and other properties of the selected diaphragm material. Additionally, diaphragms of thin, thick or non-uniform thickness may be used to manage the diaphragm to allow some areas of the diaphragm to flex more easily than others, thereby aiding in managing the pumping action and flow of the subject fluid within the pump chamber 3406. The diaphragm 3408 in this embodiment is shown with the greatest cross-sectional thickness near the center. However, in other embodiments having a diaphragm 3408 with a non-uniform cross-section, the thickest and thinnest regions may be anywhere on the diaphragm 3408. Thus, for example, the thinner cross-sectional thickness may be located near the center of the diaphragm 3408, and the thicker cross-sectional thickness may be located around the periphery of the diaphragm 3408. Still other configurations are possible. 35B-E, an embodiment of a diaphragm is shown having various surface embodiments of non-uniform thickness and / or morphology located at various locations on the actuation and / or pumping side of the diaphragm 3408, such as smooth (FIG. 35), ring-like (FIG. 35E), ribbed (FIG. 35D), dimpled or dotted (FIG. 35C), etc. In one embodiment of the diaphragm, the diaphragm has a tangential taper at least in one area, while in other embodiments the diaphragm is completely smooth or substantially smooth.

[0168] 35A, there is shown a pictorial exploded view of an exemplary embodiment of a pod pump 3500. This figure illustrates one embodiment of a port, an exemplary embodiment of which is described below with respect to FIG.

[0169] In this embodiment, the housing is made of three sections. Two of the sections 3502, 3504 may be joined to form a pump chamber 3506 (sections 3502, 3504 are referred to as the "pump chamber sections"). A third section 3508 (referred to as the "actuation chamber section") contains an actuation chamber 3512 and an actuation port 3510 for communicating fluid pressure to the actuation chamber 3512. The pump chamber sections 3502, 3504 may be joined to form a pump chamber assembly. This assembly may be joined to the actuation chamber section 3508 to form the housing.

[0170] A diaphragm 3514 is connected to the interior of the housing. In this exemplary embodiment, the diaphragm 3514 is sandwiched between the pump chamber 3506 and the actuation chamber 3512. The diaphragm 3514 separates the actuation chamber 3512 from the pump chamber 3506.

[0171] In this exemplary embodiment, if the pump chamber 3506 is made of two parts 3502, 3504, and these parts are molded, this design may minimize flash or burrs. Thus, in this embodiment, the pump chamber is free of burrs in the fluid path and provides a gentle pumping environment. This embodiment may be advantageous for use with shear sensitive subject fluids and / or when pumping delicate subject fluids. Therefore, burrs or burrs must be avoided.

[0172] In the exemplary embodiment shown in Figure 35A, the pump 3500 is shown to have two ports 3518, 3516. For ease of explanation, these ports 3518, 3516 will be referred to as the "inlet" and "outlet" ports. However, either of the ports 3518, 3516 can function as an inlet port, and similarly either can function as an outlet port. The pump inlet and outlet ports 3516, 3518 connect to the pump chamber 3506 at edges 3520 and 3522. In one embodiment, if the edges 3520, 3522 were molded using a telescoping tang, the edges 3520, 3522 would remain sharp and burrs would be unavoidable. However, in this exemplary embodiment, the pump may be manufactured without the use of a telescoping tang, and the edges 3520, 3522 may be radiused, thus eliminating burrs or burrs from the flow path that may damage delicate or sensitive target fluids.

[0173] 35A, as shown in this exemplary embodiment, the pod pump 3500 includes three housing sections 3502, 3504, 3508 and a diaphragm 3514. Two housing sections 3502, 3504 form a pump chamber 3506 and two ports 3516, 3518. The third section 3508 forms an actuation chamber 3512. The diaphragm 3514 is attached between the pump chamber 3506 and the actuation chamber 3512 by clamping the diaphragm flange 3520 to the periphery 3524 of the housing sections. It is noted that the diaphragm flange 3520 is an integral O-ring in one embodiment, although any other shape of gasket is possible in other embodiments. In the embodiment shown in FIG. 35A, the diaphragm 3514 has a tangential edge. The tangential edge is where the diaphragm 3514 is not a continuous dome-like shape. Thus, in one area, the diaphragm has a conical shape as indicated by a tangential edge. Although a tangential edge is illustrated in this embodiment, in alternative embodiments, the diaphragm may include a variety of surfaces, which may include, but are not limited to, one or more of dimples, rings, ridges, ribs, smooth, or other non-uniform surfaces.

[0174] As discussed above, the pump chamber 3506 and the ports 3516, 3518 are formed by two housing portions 3502, 3504. These portions 3502, 3504 mate together as described below with respect to Figures 36A-36C.

[0175] 36A and 36B, side and end views of the assembled pump 3500 of FIG. 35 are shown, with pump chamber portions 3502 and 3504 and actuation chamber portion 3508 joined together and diaphragm 3514 hidden and not shown. The components of the pod pump housing may be joined together in a variety of ways, including but not limited to snap tabs, press fits, snap fits, solvent bonding, heat welding, electromagnetic welding, resistance welding, RF welding, screws, bolts, ultrasonic welding, adhesives, crimping with components that contact the pump during use, or other joining methods commonly used in the art.

[0176] In the exemplary embodiment shown in Figures 35A-41B, the pod pump 3500 housing includes three sections with some features unique to the sections that are ultrasonically welded together. The design of the three sections includes features that allow the sections to be joined by ultrasonic welding, while the resulting pod pump may result in minimal, if any, damage to the delicate subject fluid when pumping the subject fluid after ultrasonic welding. The three sections of the housing and features for assembly are described below. Although the embodiments are described with respect to ultrasonic welding, it should be understood that the embodiments may alternatively be laser welded, or may be joined using snap tabs, press fits, snap fits, solvent bonds, heat welds, electromagnetic welding, resistance welding, RF welding, screws, bolts, adhesives, crimping with components that contact the pump during use, or methods commonly used in the art.

[0177] Referring to Figure 36C, a close-up of the port is shown. This is the inlet or outlet port shown in Figure 35A. In this embodiment, the inlet and outlet ports can be used as either and have similar internal and external configurations, although the locations may differ.

[0178] In this embodiment, the housing portions 3502, 3504 are joined to form a port 3604. In this embodiment, the pump chamber portions 3502, 3504 are shown joined by ultrasonic welding at the energy director 3602. However, in alternative embodiments, other joining methods may be used, as discussed above. A zone 3606 where the housing portions 3502, 3504 are joined is at least partially separated from the fluid path of the port 3604 by an area 3608. The area 3608 is formed after joining the housing portions 3502, 3504. In one embodiment, the area 3608 increases the resistance to flow, such that the area 3608 creates a flow path that is more resistive than the main flow through the chamber. Thus, the area 3608 is a flow restricting area. Thus, fluid flow into the zone 3606 where the housing portions meet is reduced. The flow restricting area 3608 can be any desired size, but in the illustrated embodiment, the flow restricting area 3608 is created with a distance between the two portions ranging from 0.001 inches to 0.005 inches, and in some embodiments ranging from 0.015 inches to 0.020 inches. However, the area 3608 can be any desired size and may vary depending on several variables including, but not limited to, the volume of the fluid, the volume of the chamber, and the pump flow rate. In many embodiments, the distance between the two portions 3502, 3504 that create the area 3608 is a small fraction of the size or volume of the primary flow path. In other embodiments, the area 3608 has any desired size or volume that provides a desired resistance to fluid flow toward the area 3606.

[0179] In alternative embodiments and in some of these embodiments, the area 3608 may be larger or smaller in extent depending on the overall volume of the pod pump. The flow restricting area 3608 provides a means for fluid to flow across the flow restricting area 3608 and experience much more resistance than fluid flowing through a larger area of ​​the port 3604. Because less fluid flows through the flow restricting area 3608 and reaches the zone 3606 where the housing components are joined, less fluid comes into contact with burrs, flash, surface irregularities, or surface impurities that may be present in the area 3606 where the housing components are joined. This avoidance of burrs, burrs, surface irregularities, and other effects resulting from various joining methods may result in gentler and safer transfer of sensitive or sensitive subject fluids as desired in certain applications.

[0180] The curved edges 3612 of the pump housing portions 3502, 3504 provide a particularly delicate environment for the subject fluid, liquid or gas passing through the pump 3500. Although the flow restriction areas 3608 and curved edges 3612 are shown in specific locations in Figure 36C, these features can be present in any desired area within the pump.

[0181] Referring to FIG. 37, an exemplary embodiment of a pod pump is shown. In this figure, a port is shown having a valve 3712 therein. As before, as shown, the pod pump housing has three sections 3702, 3704, 3706. Section 3702 has an actuation chamber 3704 and an alignment feature 3706 for assembly with the other two pump housing sections 3704, 3706. In this embodiment, pump housing sections 3704, 3706 have an area 3712 where a one-way valve may be mounted. The housing sections 3702, 3704, 3706 may be joined by ultrasonic welding, laser welding, snap interlock features, screws, bolts, adhesives, or other joining methods commonly used in the art.

[0182] In this embodiment, a ribbed diaphragm 3714 is shown. However, in alternative embodiments, the diaphragm 3714 may include one or more of the uneven surfaces described above, or may be smooth. Although each of the various figures herein shows one embodiment of a diaphragm, any embodiment of the diaphragm may be used with any embodiment of the pod pump.

[0183] 38A and 38B, an alternative embodiment of a pod pump 3800 is shown. In various embodiments, the pod pump 3800 is connected to a system, container, etc. from which and / or to which fluid is to be pumped. In some embodiments, the fluid is pumped to / from the system, container, etc. via a pipe or tube. In one embodiment, the fluid is pumped through a flexible tube. In either case, in these embodiments, the pipe or tube is connected to the inlet and outlet ports 3814 of the pod pump. However, in alternative embodiments, the fluid may be pumped through molded fluid tubes, or the ports may be directly connected to a fluid source or to where the fluid is being pumped.

[0184] 38A and 38B, the housing is a multi-piece design similar to that shown in FIG. 37, which includes two part pump chamber housings 3704, 3706, except that in this embodiment, a barbed hose connector 3802 is shown for connecting flexible tubing (not shown). In other embodiments, other means for connecting to the system may be used, including but not limited to quick connects, press fits, direct bonding of tubing to the inlet or outlet ports, or other means and methods commonly used in the art.

[0185] Referring to Figure 38B, a cross-sectional view of the embodiment shown in Figure 38A is shown. In this embodiment, a valve 3816 is mounted within the port 3814 portion of the housing portion (shown as 3806, 3804 in Figure 38A). The valve 3816 controls the flow of a target fluid into and out of the pump chamber 3818 when the diaphragm 3808 is actuated by a change in liquid or gas pressure in the actuation chamber 3810. As shown in this embodiment, the valve 3816 is a duckbill valve, however, in other embodiments, the valve 3816 can be any passive or active valve, including but not limited to a ball check valve, a flapper valve, a volcano valve, an umbrella valve, a poppet, a controlled valve, or other types of valves used in the art. In this embodiment, the fluid path 3812 is located near the top of the pump chamber 3818 and has a portion that is not obstructed by the diaphragm 3808 even when the diaphragm is fully inserted into the pump chamber 3806 by liquid or gas pressure applied to the actuation chamber 3810 via the actuation port 3820.

[0186] As shown in this embodiment, the diaphragm 3808 includes a ring, but as noted above, the diaphragm 3808 may include dimples, rings, and / or ribs, or any other surface irregularities, or in some embodiments, may not include surface irregularities. Various embodiments of this diaphragm may be used in any of the pod pump embodiments.

[0187] Referring to FIG. 39, an exploded pictorial view of one embodiment of a pod pump 3900 is shown. In some embodiments, the valve 3902 may be mounted at the inlet and / or outlet ports of the pump housing portions 3906 and 3916. The valve 3902 may be any passive or active valve, including but not limited to duckbill valves, ball check valves, flapper valves, volcano valves, umbrella valves, poppets, controlled valves, or other types of valves used in the art to control fluid flow. A diaphragm 3908 is attached between the pump chamber housing portions 3906, 3916 and the actuation housing portion 3910. The diaphragm 3908 is made of any material that is sufficiently flexible and durable to deflect in response to fluid pressure or vacuum applied to the actuation chamber 3910. The material of the diaphragm 3908 may be selected for particular biocompatibility, temperature compatibility, or compatibility with various gases or liquids that may be introduced into the actuation chamber.

[0188] The diaphragm 3908 may have a ring of thickness 3912 near its outer diameter that sits or fastens into the mating features of the pod pump housing components 3906, 3916, and 3910. The moving portion of the diaphragm 3908 has two surfaces, which for purposes of explanation are referred to as the "external surface" and the "internal surface." The external surface is the pump chamber surface and the internal surface is the actuation chamber surface. Either surface of the moving portion of the diaphragm may or may not be of uniform thickness, and both surfaces need not be the same. Various embodiments of the surfaces are shown in Figures 35B-E.

[0189] One or both surfaces may be smooth or may include one or more features including, but not limited to, dimples, dots, rings, ribs, grooves or bars that protrude or are recessed from the surrounding surface. In this embodiment, an arrangement of dots 3914 is shown on the exterior surface of the diaphragm.

[0190] The surface features, or lack thereof, may serve several functions. One is to provide space for fluid to pass through the pump chamber. Another is to help seal the diaphragm against the pump chamber housing in applications where it is desirable to prevent fluid flow through the pump chamber when the diaphragm is pressed against the pump chamber housing by liquid or gas pressure in the actuation chamber. Some diaphragm surfaces may provide one or more of these features, or may provide other functions or features.

[0191] Features on the exterior or interior surfaces of the diaphragm may act to cushion the movement of the diaphragm at the end of one of its strokes. When features on the diaphragm contact the pump chamber wall or actuation chamber wall, these features stop moving, but the diaphragm material between the features may continue to move, gently accelerating or decelerating the fluid being pumped as it flows into or out of the pump chamber.

[0192] Referring to FIG. 40A, there is shown a pictorial view of the multi-piece pump portions 3906 and 3916 shown in FIG. For illustrative purposes only, pump housing portions 3906 and 3916 are shown in a bottom-to-bottom orientation to illustrate the relationship of alignment and joining features that may be used for the pump portions of a multi-piece pod pump housing. In this exemplary embodiment, portions 3906 and 3916 are aligned and joined in two locations, although in other embodiments, this feature may be different and the two portions may be joined at different locations. For illustrative purposes, one of the alignment and joining features is described in FIG. 40B, although of course only one will be described, but the details apply to both.

[0193] Referring to Figure 40B, there is shown an enlarged depiction of a region of Figure 40A. The pump housing portion 3916 has an alignment feature 4002 that may align with a complementary alignment groove 4004 on the housing portion 3906. In this embodiment, the alignment feature 4002 includes an energy director 4006 such that the housing portions 3906 and 3916 may be joined by ultrasonic welding. In this embodiment, the energy director is located in alignment with a recessed region 4008 at the bottom of the pump housing 3916. In embodiments in which the diaphragm includes a peripheral ring, the recessed region 4008 may accommodate the peripheral ring of the diaphragm (not shown).

[0194] The undercut area 4008 is continuous in the pump housing portion 3906 but is only visible as an edge 4010. In this embodiment using ultrasonic welding, flash from the energy director 4006 may attempt to flow over the edge 4010 upon assembly. Because the energy director 4006 is aligned with the perimeter ring of the diaphragm (not shown), the flash will contact the perimeter ring of the diaphragm which will flex and seal despite the presence of flash on the sealing surface of the perimeter ring of the diaphragm. If alternative joining methods are used, such as but not limited to laser welding, adhesives, screws or other fasteners, the energy director 4006 may be omitted and the configuration of the alignment features 4002 and 4004 may differ from the embodiment shown.

[0195] In this embodiment, as shown in the previous and subsequent figures, there is further an alignment mechanism 4012 and an energy director 4014 to orient the pump housing components 3906 and 3916 so that they can be joined all the way to the bottom where they are joined to the actuation housing (not shown).

[0196] 41A, there is shown a pictorial view of a partially assembled pod pump 4100. For purposes of illustration, only one portion of the pump housing 3916, a portion of a possible embodiment of the diaphragm 4102, and a portion of the actuator housing 4104 are shown.

[0197] Referring to Figure 41B, an enlarged depiction of a region of Figure 41A is shown. In this embodiment of the actuator housing 4104, two energy directors 4106 and 4108 are shown for ultrasonic welding together, although other joining methods are possible. In this embodiment, the energy director 4108 is aligned with the energy director 4014 on the pump housing portion 3916. Arranging the energy directors as shown in this embodiment ensures that flash from one weld is consumed by the other ultrasonic weld and ensures a good seal between the three housing portions. Note that one of the housing portions has been removed from the illustration for clarity.

[0198] 41A and 41B, there is shown the alignment of the energy director 4006 with respect to the outer perimeter of the diaphragm 4102. This alignment of the energy director 4006 with respect to the diaphragm 4102 allows any flash created by ultrasonic welding in the area of ​​the energy director 4006 to be sealed with the flexible material of the diaphragm 4102.

[0199] The pod pump housing can be made of any material including any plastic, metal, wood, or combinations thereof. In one exemplary embodiment, the pod pump housing is made of medical grade polycarbonate. In another exemplary embodiment, the pod pump housing is made of polysulfone. As detailed in the description, in some embodiments, compatibility of the selected material with the target fluid can be a factor.

[0200] 42A-42D, alternative shape embodiments of a pod pump 4200 are shown. The shape embodiments shown herein are for purposes of example and explanation only. Of course, in alternative embodiments, the pod pump can be of any desired shape.

[0201] The pod pump housing may be manufactured using any of a number of manufacturing methods, including, but not limited to, injection molding, compression molding, casting, thermoforming, or machining, In some embodiments, for example, if the housing is machined, the housing may be attached with mechanical fasteners or heat welds.

[0202] The wall thickness of the pod pump housing may vary from embodiment to embodiment. A myriad of variables may factor into the selection of wall thickness, including but not limited to the housing material used, the pressure at which the fluid is pumped, the size of the chamber, the overall size of the pod pump, the strength required depending on the materials used, durability, assembly method, the equipment the pod pump may be integrated into and function with, cost and manufacturing time, etc. In some embodiments, the pod pump has variable wall thickness.

[0203] In various embodiments, the wall thickness ranges from 0.005 inches to any thickness. The term "any thickness" is used because in some embodiments, the pod pump is integrated into an instrument or machine. Thus, the walls of the pod pump may be the same thickness as the entire machine. Thus, in some cases, the wall thickness can be quite large. In the exemplary embodiments described herein, the wall thickness ranges from 0.04 inches to 0.1 inches. In other embodiments, the wall thickness ranges from 0.06 inches to 0.08 inches.

[0204] The choice of materials and manufacturing methods for various embodiments of the pod pump may depend on several variables, such as durability, cost, pressure from fluid, performance, and many others. In some embodiments, the pod pump housing and diaphragm are intended to last for months or years. In other embodiments, the pod pump is intended to be disposable for single use. In still other embodiments, the pod pump is intended to last for hours, days, weeks, or years. In some embodiments, even if the pod pump is intended to be disposable for single use, it is designed to pump for longer periods of time, such as days, weeks, months, or years.

[0205] In one embodiment of the disposable device, the housing is made of a thin film, including but not limited to materials such as PETE (polyethylene terephthalate), PETG (glycol modified polyethylene terephthalate), and PET (polyethylene terephthalate). In these embodiments, the housing may be thermoformed, e.g., vacuum or pressure formed, and the diaphragm is formed from a thin plastic film that can be heat sealed to the housing. In some embodiments, the housing is a multi-layer film. This embodiment is useful for adhering the housing to another component.

[0206] The pod pump may be incorporated and / or used with other devices, machines, vessels, etc. In some embodiments, a single pod pump is used. However, in other embodiments, two or more pod pumps are used. In some embodiments, the pod pump is incorporated into a device that is further integrated into or attached to a machine, device, vessel, etc. An example of this embodiment is a cassette having an integrated pod pump, fluid paths, fluid ports, actuation ports, and actuation fluid paths. Two cassette embodiments are described in Figures 43A-43C and 44A-44B. Many more embodiments are contemplated. For purposes of illustration, exemplary and alternative embodiments are described. However, these are merely exemplary and other embodiments are contemplated, including more or less than two pod pumps, different valves or various flow paths, and / or incorporating additional vessels or other devices.

[0207] 43A-43C, one embodiment of a pod pump cassette 4300 is shown. With reference to FIG. 43A, this embodiment of a pod pump cassette includes two pod pumps 4310. While the pod pumps 4310 can be any of the pod pump embodiments, in this exemplary embodiment, the pod pumps 4310 are similar to the pod pumps shown in FIGS. 33A-33B. The cassette 4300 includes three plates: an actuation plate 4320, a middle plate 4330, and a pump chamber plate 4340.

[0208] The actuation plate 4320 includes a pod pump actuation chamber housing 4312 portion and two valve actuation housing 4314 portions for each pod pump 4310. The valve actuation housing 4314 includes valve actuation ports 4316. In some embodiments, in addition to the pod pumps, the cassette 4300 may contain additional ports and / or reservoirs through which various fluids may be pumped in and out.

[0209] The middle plate 4330 includes a pump diaphragm 4332 for each pod pump, and two valve diaphragms 4334. In the embodiment shown, the valves are volcano or active valves actuated by diaphragm 4334 which is actuated by a fluid, which in this embodiment is compressed air. Also shown in this embodiment of cassette 4300 are additional diaphragms in middle plate 4330. These are for embodiments that may contain reservoirs with various fluids pumped in and out.

[0210] Referring to the pump plate 4340, each pod pump 4310 includes a pump chamber housing 4342 that includes an integral fluid path 4344. The pump chamber housing 4342 is fluidly connected to an external fluid path 4346. In this exemplary embodiment, the three plates 4320, 4330, 4340 are laser welded together. However, in other embodiments, a variety of attachment modes may be used, some of which are described above.

[0211] 43B, there is shown a cross-sectional view of cassette 4300. Shown is the volcano valve including valve diaphragm 4334, valve actuation housing 4314 portion and external fluid tube 4346. The valve is actuated by compressed air through actuation port 4318.

[0212] Referring to FIG. 43C, in one embodiment, the cassette may include an air filter 4350 and an additional fluid conduit 4352 .

[0213] An alternative embodiment of a cassette is shown in Figures 44A and 44B. With reference to Figure 44A, a cassette 4400 includes four more sections. The section includes a middle plate 4410 to which multiple covers 4412-4416 are laser welded. The multiple covers 4412-4416 are used in place of the pump plate shown as 4340 in Figure 43A. With reference to Figure 44B, the middle plate 4410 is again shown. However, in this embodiment, multiple covers 4442-4444 are used instead of the single actuation plate shown as 4320 in Figure 43A. As shown in Figures 44A-44C, this is one embodiment, but in other embodiments the number of multiple covers may be different.

[0214] 1.5. Exemplary embodiments incorporating multiple pump pods It should also be noted that the pumping system may use multiple pump pods to pump fluid. The pump pods may be used individually, in which case the pump pods may be controlled individually. Alternatively, the pump pods may be interconnected in various ways, such as by interconnecting the inlets of multiple pump pods to draw fluid from a common source, interconnecting the outlets of multiple pump pods to pump fluid to a common destination, and / or interconnecting the pneumatic ports of multiple pump pods to control them through a common pneumatic interface. In various embodiments, multiple pump pods may be operated out of phase (i.e., one pumping chamber is empty while another is filling) to provide a substantially continuous flow, in phase to provide a pulsating flow, or in other ways. For in phase operation, a single pneumatic interface for multiple pump pods may be provided so that a base station can operate the pump pods simultaneously. Similarly, a single pneumatic interface for multiple valves may be provided so that a base station can operate the valves simultaneously.

[0215] In the embodiment shown in Figures 2 and 48, the disposable system includes two independent, self-contained pump pods 25a and 25b of the type shown in Figure 3. In this embodiment, pump pods 25a and 25b each have a dedicated pneumatic port 38 so that pump pods 25a and 25b can be controlled separately.

[0216] In the embodiment shown in Figures 5A and 5B, two pump pods 25a and 25b are assembled into a larger assembly 2004 such that the inlets of the two pump pods 25a and 25b are connected to a common inlet tube 54 and the outlets of both pump pods 25a and 25b are connected to a common outlet tube 57. Figure 5B shows the pneumatic ports 38 of the pump pods 25a and 25b. The inlets 34 and outlets 37 of the pump pods 25a and 25b are arranged to direct the flow into and out of the pumping chamber at a substantially tangential angle to the rigid pumping chamber walls 31 of each pump pod to reduce shear forces and turbulence on the fluid and improve circulation in the pumping chamber, as discussed above. In this embodiment, the pump pods 25a and 25b have purge ports 55 that allow air to be purged from the system, for example, during priming. Additionally, in this embodiment, the common inlet tube 54 is equipped with several luer ports 2001 (e.g., to allow for attachment of additional fluid sources, e.g., medical solutions, chemical solutions, diluents, etc.) and is further equipped with thermocouples 2002 (e.g., to allow monitoring of fluid temperatures entering pump pods 25a and 25b). Additionally, in this embodiment, assembly 2004 includes two flow-through ports 2003 with tubing connections on the upper side (shown in FIG. 5A) and O-ring connections on the lower side (shown in FIG. 5B). The flow-through ports 2003 can be used, for example, to facilitate mounting of assembly 2004 to or in use with a base station by allowing all pneumatic and fluid connections to be made from the underside of assembly 2004. In that case, inlet tube 54 can be pre-connected via tubing to one of the flow-through ports 2003 and outlet tube 57 can be pre-connected via tubing to the other flow-through port 2003.

[0217] In the embodiment shown in Figures 22A and 22B, two pump pods 2025a and 2025b of the type shown in Figure 20 and several valves 2000a-2000d of the type shown in Figure 21 are incorporated into a pump cassette 2015 along with various fluid paths and other components. The pump cassette 2015 includes a common inlet 2005 in fluid communication with pump pod 2025a via fluid paths 2007 and 2009 and in fluid communication with pump pod 2025b via fluid paths 2008 and 2010. The pump cassette 2015 further includes a common outlet 2006 in fluid communication with pump pod 2025a via fluid paths 2011 and 2013 and in fluid communication with pump pod 2025b via fluid paths 2012 and 2014. Thus, pump pods 2025a and 2025b draw fluid from a common inlet 2005 and pump fluid to a common outlet 2006. Thus, valve 2000a is used to control fluid flow at the intersection of fluid paths 2008 and 2010 (i.e., the inlet to pump pod 2025b). Valve 2000b is used to control fluid flow at the intersection of fluid paths 2007 and 2009 (i.e., the inlet to pump pod 2025a). Valve 2000c is used to control fluid flow at the intersection of fluid paths 2011 and 2013 (i.e., the outlet of pump pod 2025a). Valve 2000d is used to control fluid flow at the intersection of fluid paths 2012 and 2014 (i.e., the outlet of pump pod 2025b). Pump pods 2025a and 2025b each have a dedicated pneumatic interface 2106a and 2106b, respectively. Additionally, valves 2000a-2000d each have a dedicated pneumatic interface 2096a-2096d, respectively. Thus, each pump pod and each valve can be individually controlled by the base station.

[0218] FIG. 23 is a schematic diagram of a dual housing arrangement 2016 according to another embodiment of the invention. This arrangement may be advantageously used with a disposable cassette that includes many pneumatically actuated pumps and / or valves. If the number of pneumatically actuated pumps and / or valves in the cassette is large enough, the cassette containing these pumps and valves may become very large - and the pressure required may be very high - making it difficult to properly seal and position all the pumps and valves. This difficulty may be alleviated by using two different housings. The valves and pumps (e.g., pump pod 2042) are located in the main housing 2041, from which the connecting tubes 2045 lead from the pneumatic port 2044. The main housing 2041 further includes inlet and outlet tubes 2043 that allow liquid to flow in and out of the main housing. Connecting tubes 2045 provide pneumatic communication between the valves and pumps in the main housing 2041 and a small secondary tube support housing 2046 with a pneumatic interface 2047 for each tube. Proper positioning and sealing of all of the pneumatic interfaces 2047 to the reservoirs in the base unit is easier with the small tube support housing 2046 than if pneumatic actuation were applied directly to the larger main housing.

[0219] 1.6. Alternative Chamber Configurations and Stroke Sizes It should be noted that pump pods of the above type may be configured with different chamber configurations and / or different stroke sizes. Thus, for example, pump pods with different pump volumes may be provided. Furthermore, pump pods with different pump volumes may be provided with standardized pneumatic port configurations (and possibly standardized actuation chamber wall configurations) to allow the different pump pods to be easily attached and detached to a common pumping system or device (e.g., a base unit) having a corresponding standardized pneumatic port interface. For example, a base unit may be capable of accepting a small volume pump pod for a child and a large volume pump pod for an adult. The pneumatic ports are preferably adapted for quick and easy connection and disconnection to the pneumatic actuation system of the base unit. In certain embodiments, the pump pods are considered disposable and may be provided separately or as part of a larger disposable system.

[0220] Thus, for example, in the embodiment shown in Figures 2 and 48, the disposable system (specifically for use in a heat exchange system, as discussed in more detail below) includes two self-contained pump pods 25a and 25b. Different versions of such a disposable system having pump pods with different pump volumes can be provided for different applications (e.g., a version with a smaller pump volume for children and another version with a larger pump volume for adults). Similarly, in the embodiment shown in Figures 5A and 5B, different versions of the assembly 2004 can be provided having pump pods with different pump volumes, and in the embodiment shown in Figures 22A and 22B, different versions of the cassette 2015 can be provided having pump pods with different pump volumes. Similarly, in the embodiment shown in Figure 23, different versions of the primary housing 2041 can be provided having pump pods with different pump volumes for use with a common secondary tube support housing 2046.

[0221] It should be noted that the pumping chamber walls may be shaped, formed, fabricated, or configured with features to facilitate the intake, circulation, and / or delivery of fluids. For example, the inner walls of the pumping chamber may include certain features or materials that help induce circulatory flow, induce smooth / laminar flow, reduce boundary layer effects, or even create turbulent flow (e.g., to facilitate mixing of materials or prevent solidification within the pumping chamber).

[0222] 1.7. Exemplary Diaphragm Configurations In certain embodiments, the pump pod diaphragm may include small raised bumps, grooves, or other structures, particularly on the side facing the pumping chamber. FIGS. 46A and 46B show an exemplary membrane 33 with raised bumps 39, according to an exemplary embodiment of the present invention. Such raised bumps 39 or other raised structures prevent fluid boluses from accumulating away from the inlet and outlet, particularly by keeping the membrane away from the rigid pumping chamber walls, even at maximum pumping chamber volume. This spacing keeps the flow path open for blood to flow from the periphery of the pumping chamber to the outlet. In the exemplary embodiment shown in FIGS. 46A and 46B, the bumps 39 are located away from the edges of the membrane, such that there are no bumps in the areas near the edges of the membrane. Generally, such a configuration allows the portions of the membrane near the edges to contact the pumping chamber walls, which helps to push fluid away from the edges toward the outlet.

[0223] In addition to or in lieu of bumps or other raised structures on the membrane, the pump chamber walls may include spacers or conduits to allow fluid flow as the pumping chamber approaches and reaches its minimum volume.

[0224] The membrane may be made of any of a wide variety of flexible materials, but is preferably made of high elongation silicone or a similar material to maintain smooth pumping action of the membrane and reduce the tendency of the membrane to "pop" at the minimum pumping chamber volume location. Reducing popping reduces localized force spikes on the fluid. Such popping can disrupt the swirling of the fluid within the chamber, causing excessive shear and turbulence, which can lead to hemolysis when pumping blood or foaming when pumping surfactants. Alternatively, the membrane may be made from various thermoplastic elastomers or rubbers. Additionally, the membrane may include dimples or grooves to enhance flexibility.

[0225] It should be noted that the membrane may be shaped, formed, manufactured, or configured to bias the membrane to reciprocate in a predetermined pattern or manner. For example, the membrane may be formed with portions of different thickness or stiffness such that some portions move more freely than others (e.g., the membrane may be configured such that the portion of the membrane adjacent the pump inlet is more flexible than the portion adjacent the pump outlet, such that the inlet side of the membrane retracts more quickly during a suction stroke and retracts more quickly during a delivery stroke, which in some embodiments facilitates filling and emptying the pumping chamber).

[0226] 2. Exemplary Pump Control System 2.1. Pressure actuated system 4 is a schematic diagram illustrating an embodiment of a pressure actuation system 40 according to an exemplary embodiment of the present invention that may be used to actuate a pump pod, such as pump pod 25 shown in FIG. 3. Pressure actuation system 40 may provide intermittent or alternating positive and negative pressurization to the gas in actuation chamber 42 of pump pod 25. Pump pod 25 - including flexible membrane 33, inlet 34, outlet 37, gas pressure port 38, pumping chamber 41, actuation chamber 42, and possibly inlet check valve 35 and outlet check valve 36 or other valves - may be part of a larger disposable system. Pneumatic actuation system 40 - including electronic controller 49 including actuation chamber pressure transducer 44, positive supply valve 47, negative supply valve 48, positive pressure gas reservoir 51, negative pressure gas reservoir 52, positive pressure reservoir pressure transducer 45, negative pressure reservoir pressure transducer 46 along with a user interface console (e.g., touch screen) - may be part of a base unit.

[0227] The positive pressure reservoir 51 provides a positive pressure of controlled gas to the actuation chamber 42 to bias the membrane 33 towards a position where the pumping chamber 41 has a minimum volume (i.e., where the membrane presses against the rigid pumping chamber wall 31). The negative pressure reservoir 52 provides a negative pressure of controlled gas to the actuation chamber 42 to bias the membrane 33 in the opposite direction, i.e., towards a position where the pumping chamber 41 has a maximum volume (i.e., where the membrane presses against the rigid actuation chamber wall 32).

[0228] A valve mechanism is used to control fluid communication between each reservoir 51, 52 and the working chamber 42. In Figure 4, a separate valve is used for each reservoir; that is, a positive supply valve 47 controls fluid communication between the positive pressure reservoir 51 and the working chamber 42, and a negative supply valve 48 controls fluid communication between the negative pressure reservoir 52 and the working chamber 42. The two valves 47, 48 are controlled by a controller 49. Alternatively, a single three-way valve may be used in place of the two separate valves 47, 48. The valves 47, 48 may be binary on-off valves or variable throttle valves.

[0229] The controller 49 also receives pressure information from three pressure transducers shown in FIG. 4: the actuation chamber pressure transducer 44, the positive pressure reservoir pressure transducer 45, and the negative pressure reservoir pressure transducer 46. As their names suggest, these transducers measure the pressure in the actuation chamber 42, the positive pressure reservoir 51, and the negative pressure reservoir 52, respectively. The actuation chamber pressure transducer is located in the base unit, but is in fluid communication with the actuation chamber 42 through the gas pressure port 38 of the pump pod. The controller 49 monitors the pressure in the reservoirs 51, 52 to ensure that the two reservoirs 51, 52 are appropriately pressurized (either positively or negatively). In one exemplary embodiment, the positive pressure reservoir 51 may be maintained at approximately 750 mmHG, and the negative pressure reservoir 52 may be maintained at approximately -450 mmHG.

[0230] One or more compressor type pumps (not shown) may be used to maintain the desired pressures in the reservoirs 51, 52. For example, two separate compressors may be used, one for each of the reservoirs 51, 52. The pressures in the reservoirs 51, 52 may be managed using a simple bang-bang control technique, where the compressor for the positive pressure reservoir 51 is activated when the pressure in reservoir 51 falls below a certain threshold, and the compressor for the negative pressure reservoir 52 is activated when the pressure in reservoir 52 rises above a certain threshold. The amount of hysteresis for both reservoirs may be the same or different. Reducing the magnitude of the hysteresis band allows for tighter control of the pressure in the reservoirs, but this typically comes at the expense of an increase in the periodic frequency of the compressors. If very tight control of reservoir pressure is required or desired for a particular application, the bang-bang technique may be changed to a PID (Proportional-Integral-Derivative) control technique, and a PWM (Pulse-width Modulation) signal can be used to the compressor.

[0231] The pressure provided by the positive pressure reservoir 51 is preferably strong enough to normally press the membrane 33 completely against the rigid pumping chamber wall 31. Similarly, the negative pressure (i.e., vacuum) provided by the negative pressure reservoir 52 is preferably strong enough to normally press the membrane completely against the actuation chamber wall 32. However, in a more preferred embodiment, the positive and negative pressures provided by the reservoirs 51, 52 are preferably well within safe ranges so that even with the positive supply valve 47 or negative supply valve 48 fully open, the positive or negative pressure applied to the membrane 33 is not strong enough to damage the pump pod or create unsafe fluid pressures (e.g., that could be detrimental to a patient receiving the pumped blood or other fluid).

[0232] Of course, other types of actuation systems may be used to move the membrane back and forth instead of the dual reservoir pneumatic actuation system shown in FIG. 4, although dual reservoir pneumatic actuation systems are generally preferred. For example, an alternative pneumatic actuation system may have a single positive pressure reservoir or a single negative pressure reservoir, along with a single supply valve and a single tank pressure sensor, particularly in combination with a resilient diaphragm. Such a pneumatic actuation system may intermittently provide positive or negative gas pressure to the actuation chamber of the pump pod. In an embodiment having a single positive pressure reservoir, the pump may be operated by intermittently providing positive gas pressure to the actuation chamber to move the diaphragm against the pumping chamber wall to expel the contents of the pumping chamber, and releasing the gas pressure to return the diaphragm to a relaxed position to draw fluid into the pumping chamber. In embodiments having a single negative pressure reservoir, the pump may be operated by intermittently supplying negative gas pressure to the actuation chamber to move the diaphragm against the pumping chamber wall, drawing in fluid, and then releasing the gas pressure to return the diaphragm to a relaxed position, expelling fluid from the pumping chamber.

[0233] 2.2. Alternative embodiment using active inlet / outlet valves As discussed above, active valves may be used at the pump pod inlets and outlets instead of passive check valves. Active valves allow for greater control and flexibility (albeit generally at the expense of increased complexity and cost). Among other things, active valves allow for reversal of fluid flow. This may be used, for example, to facilitate priming, air purging, and / or detection and mitigation of certain conditions (e.g., blockages, occlusions, leaks, dislodged tubing). With respect to dislodged tubing, if the outlet tubing becomes dislodged, reversing the flow may draw air into the pumping chamber through the outlet. Such air flow may be detected using any of a variety of techniques, including techniques that detect the amount of work required to move a diaphragm. If the tubing is securely connected, some work is typically required to reverse the flow and draw fluid through the outlet, but if the return tubing is dislodged, much less work is required to reverse the flow because the pump is drawing air into the return tubing. If the controller detects an abnormal flow condition immediately after flow reversal, the controller preferably causes the system to stop pumping blood from the patient.

[0234] During normal pump operation, the active valves are typically operated as follows: During a fill stroke, as fluid is drawn into the pumping chamber, the controller 49 typically opens the inlet valve and closes the outlet valve to allow fluid to enter the pumping chamber through the inlet, but prevents fluid from being drawn back out the outlet. During a delivery stroke, when fluid is pumped out of the pumping chamber (e.g., after the pumping chamber is full, or at another suitable time), the controller 49 typically closes the inlet valve and opens the outlet valve to allow fluid to be pumped out the outlet, but prevents fluid from being pumped back in through the inlet. Between strokes, the controller 49 may cause both the inlet and outlet valves to be closed for a period of time.

[0235] Additionally, for embodiments in which pneumatically actuated inlet and outlet valves (e.g., binary on-off valves integral to the pump pod or external to the pump pod) are used in place of the passive inlet and outlet check valves, such valves may be connected to the positive pressure and / or negative pressure reservoirs 51, 52 through appropriate supply valves operated by controller 49.

[0236] The use of active inlet and outlet valves facilitates the detection of air in the pumping chamber. For example, a positive pressure can be applied to the actuation chamber following a complete suction stroke to bring the pumping chamber to its maximum volume, and the rate at which the pressure in the actuation chamber (or pumping chamber) increases can be monitored. If the pumping chamber is filled with air, the pressure increases gradually because the air in the pumping chamber allows the diaphragm to move easily. However, if the pumping chamber is filled with liquid, the pressure increases rapidly because the pump diaphragm is strongly supported by the incompressible liquid.

[0237] 2.3. Pump operation During normal pump operation, the controller 49 normally monitors pressure information from the working chamber pressure transducer 44 and, based on this information, controls the valving mechanism (valves 47, 48) to urge the membrane 33 to a minimum pumping chamber volume position and, once that position is reached, to pull the membrane 33 back to a maximum pumping chamber volume position. In this embodiment, the volume may be measured by counting the number of complete fluid delivery strokes (e.g., volume = number of complete strokes x pumping chamber volume).

[0238] In an exemplary embodiment of the invention, the controller may be able to detect the end of the stroke, i.e., when the membrane reaches the solid pumping or actuation chamber wall. Referring to Figure 4, the delivery stroke is initiated by opening the positive supply valve 47, which results in a positive pressure being applied to the membrane 33. Preferably, the positive supply valve 47 is periodically opened and closed (dithered) to create a ripple in the actuation chamber pressure as long as the membrane 33 is moving. When the membrane 33 reaches the pumping chamber wall 31, the pressure ripple stops. A controller 49, receiving pressure information from the actuation chamber pressure transducer 44, monitors this pressure ripple and detects the end of the stroke when it stops.

[0239] Upon detecting the end of the dispense stroke, the controller 49 closes the positive supply valve 47 and dithers the negative supply valve 48, thereby applying a vacuum to the membrane 33. The same process that was subsequently performed in the dispense stroke is repeated in the fill stroke. The controller determines when each stroke is complete and uses that information to calculate the flow rate. The flow rate information is used to set the pressure and valving commands for the next stroke.

[0240] The controller 49 sets the flow rate using a timed sequence of alternating positive pressure and vacuum applied to the membrane 33. Positive pressure is applied for a period of time to obtain the desired delivery (i.e., discharge) flow rate. After this period of time, a vacuum is applied to obtain a constant fill flow rate. This time interval control can be an open-loop system with no feedback on flow rate, so there may be a delay between the end of one stroke and the start of the next. Such an open-loop, time-based system may be used when a closed-loop system based on flow rate would not work properly, such as during priming when a mixture of liquid and air is present in the pump pod.

[0241] As noted above, the stroke is preferably achieved by sending a series of pressure pulses (forming pressure ripples) to the membrane 33. The speed of the stroke can be adjusted by varying how often the supply valve opens and / or by varying the open time each time the supply valve is opened. A pressure pulse opens the valve between the working chamber and the reservoir for a period of time and then closes the valve for the remainder of the pulse period. The total length of the pressure pulse is 1 / (pulse pumping frequency). In one embodiment, the pulse pumping frequency increases from 2 Hz to 16 Hz as the pumping command from the controller increases from 0 to 100%. The minimum frequency of 2 Hz is intended to ensure a minimum flow rate when there is water in the system. The maximum frequency of 16 Hz is intended to correspond to the minimum time required for the valve to reach 50% duty cycle. The pumping algorithm preferably divides the stroke into two periods: an initial pumping period and an end of stroke period. During the initial pumping period, the valve opening time of the pressure pulse is preferably 166 ms (100% duty cycle at 16 Hz). Thus, with a maximum command from the controller, the valve to the reservoir is always open. As the pumping command increases from 0 to 100%, the number of pressure pulses in the initial period is increased from 1 to 10.

[0242] After the initial pumping period there is a transition to an end-of-stroke pumping period. In this regard, a software filter is preferably used to determine when the stroke ends, with at least five pressure pulses used to initialize the end-of-stroke filter during the end-of-stroke period. The end-of-stroke period ends when the end of the stroke is detected. During the end-of-stroke period, the valve open time of the pressure pulse is preferably 83.3 ms (50% duty cycle at 16 Hz). Figures 7 and 8 show pressure pulses during the initial and end-of-stroke periods. Figure 7 shows pressure pulses for a low flow command by the controller, and Figure 8 shows pressure pulses for a high flow command by the controller. It should be noted that for the high flow command the on time of the pulse is much longer.

[0243] The pressure pulse generates a ripple in the measured pressure in the actuation chamber while the membrane is moving. By filtering to isolate this pressure ripple, an end-of-stroke algorithm can detect when the diaphragm reaches the chamber wall and stops moving. This end-of-stroke information may be used for flow calculations and for sequencing the pump pods for fill and discharge strokes.

[0244] In the first stage of filtering, the pressure signal for each pump pod is passed through a bandpass filter. This filter is used to isolate the pulse pumping frequency. As discussed above, the pulse pumping frequency preferably increases from 2 Hz to 16 Hz as the controller pump command increases from 0 to 100%. Figure 9 shows the output of the bandpass filter.

[0245] The absolute value of this filtered signal is then passed through a second order low pass filter with a damping ratio of 1. The corner frequency of this filter is varied based on the pulse pumping frequency. Figure 10 shows the output of this low pass filter. The output from the low pass filter is divided by the absolute value of the supply pressure to normalize the ripple value. The final value of this pressure ripple is used to detect the end of stroke. Once in the end of stroke period, this ripple characteristically drops quickly to zero when the diaphragm is stopped by the chamber wall.

[0246] Figure 11 is a graph showing the pressure measurements in the working chambers of each pump pod in the disposable unit, as well as the results of the filtering described above. Note that the unfiltered pressure readings show that the two pump pods are out of phase, i.e., one pump pod is pumping while the other is filling. As can be seen from the plot of the filtered readings, the filtered readings drop to zero at the end of each stroke.

[0247] At the end of the stroke, the flow rate and flow direction for a particular pump pod is calculated by dividing the chamber volume by the time it takes for the stroke to complete. When the discharge stroke is complete, the variables for that stroke are reset and the process is repeated for the fill stroke.

[0248] Pressure ripples will significantly change the pressure reading during the stroke. Therefore, the average pressure is calculated and recorded. As shown in Figure 12, the average pressure is preferably calculated by integrating the pressure between the 5th and 10th pulses. In this embodiment, the 5th and 10th pulses are selected as the beginning and end of the average to eliminate the effects of pressure at the beginning of the stroke and when the diaphragm hits the chamber wall.

[0249] To check if any of the pressure transducers (working chamber pressure transducer 44, positive reservoir pressure transducer 45 or negative reservoir pressure transducer 46) is malfunctioning, the controller preferably compares the pressure readings at the end of the stroke. Referring to FIG. 4, at the end of the discharge stroke, while the positive supply valve 47 is open, the pressure readings of the working chamber pressure transducer 44 are compared with the readings of the positive reservoir pressure transducer 45. At the end of the discharge stroke, the pressure readings of the two transducers should be the same, so if the pressure readings from the two transducers are different, one of the two transducers is malfunctioning. Similarly, at the end of the filling stroke, while the negative supply valve 48 is open, the controller 49 preferably compares the pressure readings of the working chamber pressure transducer 44 with the readings of the negative reservoir pressure transducer 46. If the controller detects a significant change in these pressure readings, the controller issues a warning signal indicating that one of the transducers is malfunctioning.

[0250] Additionally, the controller can detect abnormal flow conditions by integrating the pressure readings over a period of time to obtain the amount of work done in moving the fluid. If the amount of work done rises or falls, the controller preferably issues a warning signal to indicate that something is wrong with the tube, such as a blockage, leak, or dislodgment. The ability to detect a dislodgment or leak can be particularly important when pumping blood, or other vital fluids, due to the relatively large flow rates of the fluid being pumped. In one embodiment, by integrating the pressure readings and defining a work function, the controller can detect a dislodged tube within about 3 seconds.

[0251] This calculation can take into account the head between the pod pump and the patient, however this height can be considered constant during the heat therapy treatment. This calculation can be expressed as: K fluidpath ×m pod =∫ stroke (P pod -P height_diff )dt Where: K fluidpath is the resistance in the fluid path, m pod is the mass of the fluid contained in the pod, P pod is the pressure inside the pump pod P height_diff is the pressure caused by the lift between the pod and the patient

[0252] K fluidpath and m pod Since should be constant during the thermal therapy procedure, any change in integrated pressure will indicate a change in resistance in the fluid and / or a change in mass moved during the stroke, and thus may indicate an abnormal flow condition, such as a blockage or dislodgment.

[0253] In one embodiment, the head is not monitored during the heating session. The head is calculated based on the first few pumps of the pod. These first few pumps set the baseline for the head calculation based on the following calculation: Ppod =K fluidpath m'+P height_diff where m' is the mass flow rate.

[0254] In particular, the flow rate is usually small during the first few strokes of the pod, so m' is 0 and the pressure in the pod is equal to the head pressure, i.e., P pod =P height_diff Based on this calculation, the head is assumed to be constant.

[0255] In one embodiment, the controller looks for changes in the integrated pressure between successive strokes, or changes in a low-pass filtered value of the integrated pressure over three strokes (with a small tolerance). If either of these changes are excessive, an error is signaled and pumping is stopped until the medical technician intervenes. This detection algorithm is not performed during priming due to the large changes in the integrated pressure signal that occur when there is a mixture of air and liquid in the pod.

[0256] Another method of detecting blockages at low flow rates may run in parallel with the pod pressure integration method. In this method, the controller looks for a large number of consecutive short strokes of exactly the same length. If such strokes are detected, the pod pump is not completing a stroke, likely due to a blockage or gas pressure problem. In one embodiment, an error signal is generated if seven or more short strokes have occurred for a particular pod pump. This detection method is not used during priming, since fast, short strokes are common when the chamber is filled with air.

[0257] If the end of the stroke does not occur within a predetermined number of pressure pulses (e.g., 100 pressure pulses, as discussed above in connection with Figures 7-12), the controller preferably issues an error signal. Excessive time to complete a stroke may indicate a gas pressure leak. Such checks can be performed during priming as well as during the warming process.

[0258] 2.4. Fluid flow management Typically, a single pump pod operates in a pulsatile manner: first it draws in fluid, then it pumps the fluid. Pulsatile operation may be necessary, desirable, or unique to certain applications (e.g., extracorporeal blood procedures in which blood is drawn from and returned to a patient through a single needle are inherently pulsatile because it is generally not possible to simultaneously draw and pump blood from and return it to the patient through a single needle).

[0259] In a dual pump configuration, the two pump pods may be operated from a 0 degree phase relationship (i.e., both pumping chambers operate in the same direction) to a 180 degree phase relationship (i.e., pumping chambers operate in opposite directions). The 0 degree phase relationship may be used to generate a substantially pulsating fluid flow, similar to a single pump pod. The 180 degree phase relationship may be used to generate a substantially continuous fluid flow toward and away from the pump. The 90 degree phase relationship may be used to generate a substantially sinusoidal fluid flow. Figures 74A-74C show plots of volumetric flow rate, pod volume, and total dwell flow rate for a 0 degree phase relationship, a 180 degree phase relationship, and a 90 degree phase relationship, respectively.

[0260] In some applications, it may be necessary or desirable to provide a substantially continuous fluid flow to and / or from the pump pod(s). As discussed above, a substantially continuous fluid flow may be provided using two pump pods operating in a 180 degree phase relationship. With one or more pump pods operating in a pulsating mode (e.g., a single pump pod, or two pump pods operating in a 0 degree phase relationship), one way to create a more continuous fluid flow output is to fill the pump pod(s) as quickly as possible and pump the fluid over a long period of time (e.g., the desired delivery time can be set to the desired full stroke time minus the time taken for the fill stroke).

[0261] Even when two pump pods are operated in a 180 degree phase relationship, discontinuous fluid flow can occur under certain conditions, especially if the input impedance is significantly different from the output impedance. For example, in extracorporeal blood treatment applications, the input impedance can be higher than the output impedance due to factors such as needle size (e.g., the needle used to withdraw blood from the patient may be smaller than the needle used to return the blood to the patient), blood viscosity (e.g., some patients have highly viscous blood that is diluted as part of the treatment), or patient amenity (e.g., patients with poor circulation may be limited in the rate at which blood can be withdrawn). Such impedance differences can result in differences in the fill and pump times of the pump pods, especially if the system cannot be balanced by applying a higher pressure to one pump pod than the other. (In theory, it would be possible to ensure an exact 180 degree phase relationship if there were no limit to the amount of gas pressure that could be applied to the pump pods, but there are usually physical limits - the maximum pressure in the two reservoirs - and practical limits to the pressure that can be applied.) Thus, in some cases, a stroke of one pump pod may be completed before the corresponding stroke of the other pump pod. In that case, it may be necessary to delay the former pump pod until the latter pump pod completes its stroke, causing a pause in the fluid flow generated by the former pump pod. One possible solution is to limit the flow rate to the slower of the fill and pump strokes. This results in a lower blood pumping rate, but the flow rate is still known and continuous.

[0262] 2.5. Alternative embodiment using variable throttle pneumatic valve As noted above, the positive supply valve 47 and the negative supply valve 48 in the pneumatic actuation system 40 of FIG. 4 may be variable throttle valves rather than binary on-off valves. By using variable valves, the pressure applied to the actuation chamber 42 and membrane 33 can be easily controlled to be a fraction of the pressure in the reservoirs 51, 52, instead of the full reservoir pressure on the membrane. This facilitates the use of the same reservoir or set of reservoirs for pump pods with different operating parameters such as pump volume, pump stroke size or pump actuation pressure. Of course, the reservoir pressure will generally need to be higher than the pressure required to be applied to the membranes of the various pump pods, but one pump pod may be operated at, for example, half the reservoir pressure, while another pump pod may use the same reservoir and operate at, for example, one quarter the reservoir pressure. Thus, even if different pump pods are designed to operate at different pressures, the variable valves allow them to all share the same reservoir or set of reservoirs but operate at different pressures. The pressure used by the pump pod may be varied to accommodate conditions that arise or change during pumping, for example, if a tube becomes kinked reducing flow through the tubes of the system, the positive or negative pressure or both used by the pump pod may be increased to compensate for this increased restriction.

[0263] FIG. 28 is a graph showing how the pressure applied to the pod pump can be controlled using a variable valve. The vertical axis represents pressure, P, which represents the pressure in the positive and negative reservoirs (shown as 51 and 52 in FIG. 4), respectively. R+ and P R- , and P, which represent the positive and negative control pressures acting on the membrane of the pump pod, respectively. C+ and P C- As can be seen from FIG. 28, from time T0 to about time T1, a positive pressure is applied to the actuation chamber (to force fluid out of the pumping chamber). By repeatedly decreasing and increasing the flow restriction provided by the positive variable valve (shown at 47 in FIG. 4), the pressure applied to the actuation chamber increases to approximately the desired positive control pressure P C+The pressure varies sinusoidally about the desired control pressure. An actuation chamber pressure transducer (shown at 44 in FIG. 4) in communication with the actuation chamber measures the pressure in the actuation chamber and transmits this pressure measurement information to a controller (shown at 49 in FIG. 4) which adjusts the actuation chamber pressure to the desired control pressure P C+ The controller controls the variable valve to change the pressure in the actuation chamber near the desired control pressure P. In the absence of a fault condition, the membrane is forced against the solid wall of the pumping chamber, thereby terminating the stroke. When decreasing the restriction created by the variable valve does not result in a further drop in the pressure measured in the actuation chamber, the controller determines that the end of stroke has been reached. In FIG. 28, the end of the delivery stroke occurs near time T1. Once the end of stroke is detected, the controller determines that the pressure in the actuation chamber is increased to the desired control pressure P. C+ , the controller will cause the variable valve to close completely.

[0264] After the positive variable valve is closed, the negative variable valve (shown at 48 in FIG. 4) is partially opened to cause the negative pressure reservoir to draw gas from the working chamber and therefore fluid into the pumping chamber. As can be seen in FIG. 28, negative pressure is applied to the working chamber from just after T1 until approximately time T2. As with the discharge (positive pressure) stroke above, by repeatedly decreasing and increasing the flow restriction provided by the negative variable valve, the pressure applied to the working chamber increases to approximately the desired negative control pressure P C- (less than the pressure in the negative pressure reservoir). The pressure varies sinusoidally about the desired control pressure. The actuation chamber pressure transducer sends pressure measurement information to the controller, which determines whether the actuation chamber pressure is greater than the desired control pressure P C- The controller controls the variable valve to change pressure near the desired negative control pressure P. In the absence of a fault condition, the membrane is pulled against the solid wall of the working chamber, thereby terminating the suction (negative pressure) stroke. As noted above, the controller determines that the end of stroke has been reached when decreasing the restriction by the variable valve does not result in a further drop in the partial vacuum measured in the working chamber. In Figure 28, the end of the suction stroke occurs near time T2. Once the end of stroke is detected, the controller determines that the vacuum in the working chamber is reduced to the desired negative control pressure PC- , the controller will cause the variable valve to close completely. As soon as the suction stroke is finished, the positive variable valve can be partially opened to start the next delivery stroke with positive pressure.

[0265] Thus, two variable orifice valves may be used to throttle the flow from the positive pressure source and to the negative pressure source. The pressure in the actuation chamber is monitored and the controller uses this pressure measurement to determine the appropriate commands to both valves to achieve the desired pressure in the actuation chamber. Two advantages of this arrangement are that the fill and delivery pressures may be precisely controlled to achieve the desired flow rate while respecting pressure limitations, and that the pressure may be varied with a small sinusoidal trajectory command. This trajectory may be monitored to determine when the pump has reached the end of stroke.

[0266] Another advantage of using a variable valve instead of a binary valve in this way is that the variable valve is less susceptible to wear and tear because it only partially opens and closes, whereas a binary valve is "banged" repeatedly by fully opening and closing, which can shorten its lifespan.

[0267] If the end of the stroke is detected and the integral of the correlation function is very small, this may be an indication that the stroke was obstructed and not completed properly. By looking at whether the occlusion occurs on the fill stroke or the delivery stroke, it may be possible to determine whether it is an upstream or downstream occlusion (this may be difficult for occlusions that occur near the end of the stroke when the diaphragm is near the chamber wall). Figures 73A-73B show an occlusion detection method according to an exemplary embodiment of the invention (lines 2703 and 2704 represent the time when an occlusion is detected).

[0268] In normal operation, the integral of the correlation function increases as the stroke progresses. If it remains small or does not increase, then either the stroke is too short (as in the case of very low impedance flow or an occlusion) or the actual pressure is not tracking the desired sinusoidal pressure, for example due to a malfunction of the valve or pressure signal. In these cases, the lack of correlation can be detected and used for error handling.

[0269] Under normal circumstances when the flow controller is operating, the control loop preferably adjusts the pressure to change the flow rate. If the impedance in the circuit increases too quickly and the pressure limit saturates before the flow has a chance to reach the target flow rate, the flow controller will generally not be able to adjust the pressure higher to reach the desired flow rate. This can occur when a section of tubing has formed in the circuit that is partially occluded (e.g., a blockage such as a clot in a blood pumping embodiment). Pressure saturation when the flow is not reaching the target flow rate can be detected and used for error handling.

[0270] If there is a problem with the valve or gas pressure, such as a leaking fluid valve or a noisy pressure signal, the stroke may continue to ripple indefinitely and the end-of-stroke algorithm may not see enough change in the pressure ripple to detect the end of the stroke. For this reason, it is preferable to add a safety check to detect if the time to complete a stroke is too long. This information can be used for error handling.

[0271] 2.6. Example Applications of Pump Pods Reciprocating positive displacement pumps of the above type and associated control systems may be used in a wide variety of fluid pumping applications. They are particularly well suited for use in (but not limited to) applications involving artificial or extracorporeal blood pumping, such as blood warming or cooling procedures, hemodialysis and other blood processing and filtration procedures (e.g., plasmapheresis and apheresis), cardiac bypass and other blood assisted circulation procedures (e.g., ventricular assist), cardioplegia (as part of cardiac bypass or otherwise), pulmonary bypass or artificial lung and other applications involving extracorporeal blood oxygenation, and chemotherapy and other drug treatments (e.g., regional hyperthermia chemotherapy), to name a few. For example, in certain embodiments, reciprocating positive displacement pumps of the above type and associated control systems may be used in heat exchanger systems for heating or cooling fluids such as blood. Exemplary heat exchanger systems are described below.

[0272] 3. Exemplary Heat Exchanger System DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention generally relates to a heat exchanger system that can be used to warm or cool a fluid, such as blood. Blood warming systems may be particularly useful in whole-body warming procedures (e.g., to raise body temperature to combat hypothermia or to combat certain diseases, such as Hepatitis C and possibly some types of cancer, HIV / AIDS, rheumatoid arthritis, and psoriasis), or in localized hyperthermic chemotherapy procedures. An exemplary heat exchanger system is described first for pumping and warming blood as part of a whole-body warming procedure, and then in the context of localized hyperthermic chemotherapy procedures. It should be understood that such a heat exchanger system may also be used in other applications for heating and / or cooling fluids. Additionally, although the exemplary heat exchanger system described below incorporates a pump pod of the type described above, the embodiments are not limited to the use of pump pods. In various alternative embodiments, other types of pumps may be used.

[0273] 3.1. Whole-body hyperthermia As discussed above, blood warming systems may be used for whole-body warming procedures (e.g., to raise body temperature to combat hypothermia or to combat Hepatitis C by raising the core temperature to a level that can clear the virus from infected liver cells). Generally, whole-body warming procedures for Hepatitis C require raising the core temperature to about 41.6 degrees Celsius (107 degrees Fahrenheit) for an extended period of time. A typical procedure may take 3-4 hours, including a 30-60 minute warm-up period, an 80-120 minute sustained period, and a 30-45 minute cool-down period. The core temperature, and therefore the fluid temperature generated by the heat exchanger system, must be carefully controlled to keep the patient at a nearly constant target core temperature. Too low a core temperature will result in the treatment being ineffective, while too high a core temperature may be detrimental to the patient.

[0274] FIG. 24 is a schematic diagram of a whole body hyperthermia treatment system according to an exemplary embodiment of the present invention. Blood leaves the patient via a 14F left femoral venous cannula. Within the heat exchanger system 10, the blood is pumped by two pump pods through a heat exchanger for heat exchange. A control system monitors various parameters (e.g., patient core temperature as well as blood temperature entering and leaving the warmer / cooler) and adjusts the operation of the pump pods and the warmer / cooler accordingly. Following the heat exchanger, the blood passes through a particle and air filter and returns to the patient via a 12F right femoral venous cannula. During this procedure, the patient is supine, intubated, anesthetized, and monitored by a physician or other specialist.

[0275] 3.1.1. Exemplary Heat Exchanger System FIG. 1 illustrates a heat exchanger system 10 according to an exemplary embodiment of the present invention. The heat exchanger system 10 includes a base unit 11 and a disposable unit 16. As described further below, the disposable unit 16 is mounted within the base unit 11 such that a heat exchanger bag (e.g., heat exchanger bag 21 as shown in FIGS. 2 and 48) of the disposable unit 16 enters a heat exchanger portion of the base unit 11. As blood from a patient circulates through the disposable unit 16, specifically the heat exchanger bag 21, the blood is warmed by the heat exchanger and returned to the patient. During such circulation, the blood remains within the disposable unit 16 and generally does not come into contact with the components of the base unit 11. The disposable unit 16 is generally considered to be "disposable" in that it is discarded after treatment of the patient, whereas the base unit 11 can be reused repeatedly by simply mounting a new disposable unit 16. In practice, the base unit 11 may include a mechanism to prevent reuse of the disposable unit (e.g., using a bar code, RFID (Radio Frequency Identification) tag, or other identifier associated with the disposable unit).

[0276] 3.1.2. Example Base Unit FIG. 25 illustrates a base unit 11 according to an exemplary embodiment of the present invention. FIG. 47A illustrates some of the internal components of the base unit 11 according to an exemplary embodiment of the present invention, and FIG. 47B illustrates a rear perspective view of the base unit 11. The base unit 11 includes, among other things, a heat exchanger 2541, a pneumatic actuation system 40, a disposable instrument interface 2500 (also referred to as a manifold interface), a patient interface, a controller, a user interface console 13, and a ventilation system 2701. The pneumatic actuation system 40 is generally of the type shown in FIG. 4, but may include pneumatic interfaces, valves, and sensors for each of the two pump pods. The disposable instrument interface may include two sensors thermally and electrically connectable to the disposable unit to allow monitoring of blood temperature upstream and downstream of the heat exchanger, as well as to allow monitoring of other parameters, as discussed below. The patient interface may include one or more temperature inputs 2702 to receive temperature information (particularly patient temperature information) from one or more temperature probes. The user interface console allows a user to control and monitor the operation of the system. In an exemplary embodiment, the controller controls the operation of the heat exchanger and pump pod based, among other things, on blood temperature information received from the disposable interface, pressure information received from the pneumatic actuation system, patient temperature information received from the patient interface, and user input received from the user interface console.

[0277] 3.1.3. Exemplary Disposable Unit Configurations As mentioned above, a disposable unit for a heat exchanger system typically includes a heat exchanger bag through which blood flows as it passes through the heat exchanger. The heat exchanger bag may include one or more fluid paths. In one exemplary embodiment described below, the heat exchanger bag includes a single fluid path connecting two fluid inlets to a common fluid outlet. In another exemplary embodiment described below, the heat exchanger bag includes a single fluid path having a single inlet and a single outlet. The heat exchanger bag is typically made of a flexible plastic material. However, the heat exchanger bag may be made of other materials and may include metallic or other materials to improve thermal conductivity.

[0278] FIG. 2 shows the relevant components of the disposable unit 16 according to an exemplary embodiment of the present invention. The disposable unit 16 includes, among other things, a heat exchanger bag 21 (also referred to as a "fluid bag") with a manifold 130, and a panel 2017 that holds (or is configured to hold) the two pump pods 25a and 25b and a filter / air trap 29. Preferably, the disposable unit 16 further includes a handle (not shown here, but shown in FIG. 48) that is used to mechanically interconnect the above-mentioned components into a combined unit that can be easily mounted to the base unit 11 and that preferably includes a manifold interface (described below) that receives the manifold 130 and provides a pneumatic connection for operating the pumps 25a, 25b. The bag 21 includes a fluid path 150 through which fluid is pumped. In this embodiment, the manifold 130 is integrated with the heat exchanger bag 21 and is configured with appropriate tubing connections and supports that are used to interconnect the heat exchanger bag 21 with the two pump pods 25a and 25b.

[0279] In the embodiment shown in FIG. 2, the manifold 130 includes two flow path inlets 23a and 23b (also referred to as "heat exchanger bag inlets") in fluid communication with one end of the fluid path 150, and a flow path outlet 27 (also referred to as "heat exchanger bag outlet") in fluid communication with the other end of the fluid path 150. Blood is preferably pumped from the patient through the heat exchanger bag 21 by a pair of self-contained pump pods 25a, 25b (individually referred to as "pump pods 25"), in this embodiment, preferably reciprocating positive displacement pumps of the type described herein. In this embodiment, the manifold 130 includes pneumatic conduits 138a, 138b that facilitate establishing pneumatic connections (typically using tubing) to the pump pods 25a, 25b, respectively. It should be noted that the embodiment is not limited to the use of two pump pods, or even to the use of pump pods. The manifold 130 is described in more detail below.

[0280] In this embodiment, each pump pod 25 includes an inlet 34 and an outlet 37 (i.e., pump pod 25a has inlet 34a and outlet 37a, and pump pod 25b has inlet 34b and outlet 37b). The various components may be interconnected in at least two different configurations. In a first configuration, shown in Figures 48 and 72, pump pods 25a, 25b may be connected upstream of heat exchanger bag 21 such that pump inlets 34a, 34b are connected to receive blood directly from the patient (e.g., via a "Y" connector 2024), pump outlets 37a, 37b are connected by tubing 2026a, 2026b to heat exchanger bag inlets 23a, 23b, respectively, and a filter / air trap 29 is connected by tubing 2027 to heat exchanger bag outlet 27. In this manner, the pump pods 25a, 25b operate to pump blood through the heat exchanger bag 21, where it exits the heat exchanger bag 21 through the flow path outlet 27 and passes through the filter / air trap 29 before being returned to the patient. In a second configuration (not shown), the pump pods 25a, 25b may be coupled downstream of the heat exchanger bag 21 such that blood from the patient enters the heat exchanger bag inlets 23a, 23b (e.g., through a "Y" connector (not shown)), the pump inlets 34a, 34b are coupled to the flow path outlet 27 (e.g., via a "Y" connector (not shown)), and the pump outlets 37a, 37b are coupled to return blood to the patient through the filter / air trap 29 (e.g., via a "Y" connector (not shown)). In this manner, the pump pods 25a, 25b draw blood through the heat exchanger bag 21 and pump the blood through the filter / air trap 29 to the patient. It should be noted that in alternative embodiments, the heat exchanger bag 21 may also include a separate outlet, which may in some cases facilitate connection of the heat exchanger bag 21 to a pump pod. In the embodiment shown in Figures 2 and 48, the filter / air trap 29 preferably includes a purge port to allow air to escape from the filter. Figure 48 shows a data key slot 2542 into which a data key may be inserted, for example, during manufacture.

[0281] FIG. 81 illustrates a variation of the disposable unit 16 of FIG. 48 in accordance with an exemplary embodiment of the present invention, including a patient connection circuit 2060 having a sterile protective covering 2062. Specifically, one configuration of tubing 2061 is connected between the pump pod inlet and the filter outlet to form a complete circuit. In this embodiment, the tubing 2061 includes an air purge / sample port 2019 and a blood monitoring interface including a branched sensor connection 2020 and / or a disposable H / S cuvette 2022, as appropriate. To accomplish connection to the patient, a surgeon or other technician will typically cut the tubing 2061 at or near the distal portion of the tubing (in this embodiment, the U-shaped portion pointed to by the arrow for reference number 2060, also referred to as the "circus maximus") to create two tube ends to which the surgeon or technician can then connect appropriate needles for insertion into the patient.

[0282] In this embodiment, the distal portion is sterile and covered with a thin plastic protector 2062 to maintain sterility. Prior to cutting the tube 2061, the portion of the tube 2061 that is in the sterile field is exposed, for example by pulling the protector 2062 backwards until it separates. Fig. 82 illustrates the patient connection circuit of Fig. 81 with a portion of the tubing 2061 exposed from the sterile protective covering 2062, in accordance with an exemplary embodiment of the present invention. Once this portion of the tubing 2061 is exposed, it is cut at the location indicated at 2063.

[0283] FIGURE 83 illustrates a variation of the disposable unit of FIGURE 81 including yet another fluid delivery tube 2065, according to an exemplary embodiment of the present invention. The fluid delivery tube 2065 is in fluid communication with the pump pod inlet such that fluid from the fluid delivery tube 2065 (e.g., an IV fluid) mixes with the patient's blood and circulates through the heat exchanger to the patient. In this embodiment, the fluid delivery tube 2065 is configured with a connector 2064 (e.g., a needle that is introduced into an IV bag) to facilitate connection to a fluid source.

[0284] 15, 16 and 17 show top perspective, end perspective and plan views, respectively, of an alternative heat exchanger bag 121 according to another embodiment of the present invention. In this embodiment, the bag 121 has a single inlet 123, a single outlet 127 and a flow passage 150 extending between the inlet 121 and the outlet 123. The inlet 123 and outlet 127 of this bag 121 are separate, whereas in the bag 21 of FIGS. 2 and 48, the inlets 23a, 23b and outlet 27 are adjacent to each other. Having adjacent inlets and outlets (as in the bag shown in FIGS. 2 and 48) makes the disposable unit less bulky to handle. The bag 121 may be formed from two sheets of plastic or other suitable material welded together at a seam to create the flow passage 150.

[0285] However, alternative embodiments may employ other pump pod configurations as part of the disposable unit 16. For example, various alternative embodiments may employ the pump pod assembly 2004 shown in Figures 5A and 5B, the pump cassette 2015 shown in Figures 22A and 22B, or the dual housing arrangement 2016 shown in Figure 23. For the pump pod assembly 2004, the common inlet 54 may be connected to receive blood from the patient and the common outlet 57 may be connected to supply blood to the heat exchanger bag 21. Alternatively, the common inlet 54 may be connected to receive warm blood from the heat exchanger bag 21 and the common outlet 57 may be connected to supply blood to the filter / air trap 29. Similarly, for the pump cassette 2015, the common inlet 2005 may be connected to receive blood from the patient and the common outlet 2006 may be connected to supply blood to the heat exchanger bag 21. Alternatively, a common inlet 2005 may be connected to receive warm blood from the heat exchanger bag 21 and a common outlet 2006 may be connected to supply blood to the filter / air trap 29 .

[0286] It should be noted that the various components of the disposable unit 16 may be provided separately and / or in various assemblies and subassemblies. Thus, the term "unit" is not intended to imply that the disposable instrumentation must be provided as a complete system or kit. Thus, for example, the pump pod (or pump pod assembly / cassette) may be provided separately from the rest of the disposable unit 16. In particular, providing the pump pod separately allows for easy integration of pump pods of various volumes without the need for different versions of the main disposable unit for each different pump volume. Additionally, the disposable unit 16 may be provided with some of the tubing connections already in place, for example, with the pump outlets 37a, 37b connected to the heat exchanger bag inlets 23a, 23b and / or with the pump inlets 34a, 34b connected to a "Y" connector and / or with the fluid line outlet 27 connected to the filter / air trap 29.

[0287] In an exemplary embodiment, the same controller 49 preferably controls both pump pods (shown as 25a and 25b in Figures 2 and 48) of the disposable unit 16, and preferably (though not necessarily) pumps the two pump pods out of phase (i.e., one pumping chamber is filling as the other is emptying) during normal blood pumping operation to provide a more continuous flow to / from the patient and through the warmer. The manner in which the controller 49 may monitor and control the pumps, warmer and other components is described above and further below.

[0288] 3.1.4. Exemplary Heat Exchanger Components FIG. 13A shows details of the heat exchanger 2541 shown in FIG. 25. In this embodiment, the upper warming plate 12 is mounted in the door 18 located at the top of the base unit. The lower warming plate 14 is located in the base unit 11 below the door 18. The heat exchanger bag 21, which is part of the disposable unit 16, is placed on top of the lower warming plate 14 such that when the door 18 is closed, the bag 21 is between the two warming plates 12, 14. This arrangement generally allows more heat to be transferred to the blood faster than a single plate arrangement. However, in alternative embodiments, a single plate may be used above or below the heat exchanger bag 21 and / or other types of warming elements may be used. The door 18 and / or the upper plate 12 may include a pneumatic sealing track to evacuate air from the heat exchanger or to improve the connection between the upper plate 12 and the bag 21 (e.g., by creating a vacuum that pulls the top surface of the bag 21 into contact with the upper plate 12).

[0289] Each heating plate 12, 14 may include a single heating element or multiple heating elements. The heating elements are typically (but not necessarily) electrical heating elements. FIG. 14 shows an exploded view of an exemplary heating element configuration in which the upper heating plate 12 includes a single heating element 141 and platen 142, and the lower heating plate 14 includes a single heating element 143 and platen 144. FIG. 18 shows an alternative heating element configuration in which each heating plate 12, 14 includes seven heating elements 182, 183, 184, 185. In effect, electricity flowing through the heating elements heats the heating elements, which in turn heat the platens, which transfer heat to the blood passing through the heat exchanger bag. Note that the heating elements can be used without the platens, but the platens tend to distribute the heat more evenly. In the embodiment shown in FIG. 18, even if one or more heating elements fail, the heat exchanger can still perform at least some warming of the blood, since in many cases the platen can be warmed by fewer than all of the functioning heating elements to provide heat to the blood passing through the heat exchanger bag.

[0290] To improve thermal coupling between the warming plates 12, 14 and the heat exchanger bag, the door 18 may be adapted to seal substantially airtight when closed. Additionally, air may be evacuated around the heat exchanger bag to achieve improved thermal coupling between the bag and the plate. In this regard, air may be evacuated from around the heat exchanger bag using a compressor (not shown) that creates positive and / or negative pressure for the reservoirs 51, 52. Cooling fins 131 or other elements may be provided to dissipate excess heat.

[0291] The temperature inside the heat exchanger may be monitored to ensure that the blood is not heated to such an extent that it is damaged. In the embodiment shown in FIG. 18, each heating plate includes two temperature sensors 180, 181 located near the outlet 27 and close to where the blood should be hottest. Because the inlet 23 is closer to the outlet 27 (as shown), the blood flowing through the outlet may be slightly cooler than that further upstream, as the cooler blood flowing through the inlet cools the warmer blood flowing through the adjacent outlet. Three of the heating elements 182, 183, 184 are located at the end of the flow path within the heat exchanger bag 21. Each temperature sensor 180, 181 may be located between the heating elements and near the outlet 27, and preferably some distance away from at least one heating element (in this embodiment, heating element 183) located between the temperature sensors 180 and 181. Thus, as shown in FIG. 18, one sensor 181 is located between the last two heating elements 183, 184 that the flow path traverses before the blood exits the outlet 27. The other sensor 180 is located upstream of these two heating elements 183, 184, between the two heating elements 182, 183. If the two temperature sensors 180, 181 are functioning correctly and the heat exchanger is functioning correctly, the difference between the readings of the two temperature sensors should be within a certain temperature range (although they will not usually indicate exactly the same temperature). The controller preferably receives temperature information from the two temperature sensors 180, 181 and may issue a warning, interrupt operation, reduce power to the heating elements, and / or take other action if one (or both) of the temperature sensors indicates an unsafe temperature or if the difference between the temperature readings measured by the two sensors exceeds a predetermined limit. The maximum temperature of the plate must not exceed the maximum allowable temperature of the blood. Otherwise, the blood could overheat if its flow stops or slows.

[0292] In certain embodiments, one or both of the warming plates 12, 14 may be vertically translatable when the door is closed, for example, to facilitate purging air from the heat exchanger bag 21 during priming, or to squeeze any remaining blood out of the heat exchanger bag 21 back to the patient at the end of a blood warming session. Additionally or alternatively, the plates may be tiltable so that the bag can be tilted to aid in removing air bubbles from the bag during priming, or to aid in returning blood to the patient. Such vertical translation and / or tilting may be performed manually or automatically, for example under the control of controller 49.

[0293] Thus, at the end of a blood warming session, the membranes in the pump pods 25a, 25b may be pressed against the pumping chamber walls to minimize the volume of the pumping chamber and expel as much blood as possible towards the patient. Additionally, in embodiments including a vertically translatable and / or tiltable plate, the heat exchanger bag 21 may be squeezed and / or tilted to return as much blood as possible to the patient.

[0294] 3.1.5. Exemplary Manifolds and Manifold Interfaces 49A and 49B show perspective back and bottom views, respectively, of the manifold 130 of FIG. 2, according to an exemplary embodiment of the present invention. FIG. 49A shows bag inlet and bag outlet connectors 2053, 2054 for connecting to the inlet and outlet openings of the fluid passageway 150 of the bag 21. The bag inlet connector 2053 is in fluid communication with the inlets 23a, 23b, and the bag outlet connector 2054 is in fluid communication with the outlet 27. Thermowells 133a and 133b are shown in the outlet and inlet fluid paths, respectively. Pneumatic interfaces 139a, 139b are shown that are used to supply pneumatic pressure from the base unit 11 to the pneumatic ports 138a, 138b.

[0295] Figure 13B shows a perspective rear cross-sectional view of the manifold 130 of Figures 2, 49A and 49B according to an exemplary embodiment of the invention. In this embodiment, the manifold 130 includes an inlet thermowell 133a located in the bag inlet 23a and an outlet thermowell 133b located in the bag outlet 27. The thermowells 133a, 133b interface with corresponding probes in the manifold interface of the base unit 11 (discussed below) when the disposable unit 16 is installed in the base unit 11. Figure 13C shows a close-up view of the exemplary thermowells.

[0296] The thermowells 133a, 133b provide thermal and electrical interconnection between the base unit 11 and the disposable unit 16. In particular, such thermal and electrical interconnection allows the controller 49 to monitor blood temperature as blood flows in and out of the heat exchanger bag 21, as well as to enable the controller 49 to make other measurements (e.g., detect the presence of blood or air in the heat exchanger bag 21, and perform leak detection), as discussed below. In this embodiment, the thermowells 133a, 133b are coupled to have a portion that is in a direct fluid path (i.e., in contact with blood) to enhance transfer of blood temperature from the disposable unit 16 to the base unit 11. Alternatively or in addition to a thermowell, the disposable unit 16 may include other temperature probes / sensors and interfaces that the controller 49 may use to monitor blood temperature as blood flows in and out of the heat exchanger bag 21.

[0297] It should be noted that although the exemplary embodiments shown in Figures 13B, 49A and 49B include a thermowell that transmits thermal information to the base unit 11 and is optionally used for conductivity sensing, other types of sensor components may be used in addition or instead. For example, instead of using a thermowell, a sensor component may be used that sends a temperature measurement or signal to the base unit 11. Various types and configurations of sensors are described below.

[0298] Additionally, the manifold 130 includes various tube supports that support the tubing extending from the pump (shown at 25a, 25b in FIG. 2) and the heat exchanger bag (shown at 21 in FIG. 13A). These tubes include those leading from the pump outlet (shown at 37a, 37b in FIG. 2) to the heat exchanger bag inlets 23a, 23b. The heat exchanger bag outlet 27 is also supported by the tube supports. In a preferred embodiment, the tube support 130 further supports the tubing leading to the pump pneumatic port (shown at 38 in FIG. 3) and provides an interface connection between the pump pneumatic port and the base unit pneumatic actuation system (shown at 40 in FIG. 4). The tubing from the pneumatic port extends into pneumatic conduits 138a, 138b in the tube support 130. Pneumatic conduits 138a, 138b are in fluid communication with pneumatic interfaces 139a, 139b, respectively. Pneumatic interfaces 139a, 139b connect to reservoirs in the base unit, which provide fluid communication with the pneumatic actuation systems for each pump. This arrangement facilitates the manufacture of the disposable unit's interface to the base unit and facilitates the attachment of the disposable unit to the base unit. Instead of manufacturing the pump with the pneumatic ports properly positioned relative to each other for attachment to the base unit, a more compact tube support 130 may support the pneumatic interfaces 139a, 139b in the correct position. The smaller and simpler structure of the tube support 130 facilitates the manufacture of the pneumatic interfaces 139a, 139b to the tolerances required for attachment to the base unit 11. The disposable unit 16 may further include a data key or other mechanism for interfacing with the base unit 11 to provide relevant information to the base unit 11 (e.g., the disposable unit's serial number and usage information) and / or to store information provided by the base unit 11 (e.g., usage information).

[0299] A similar arrangement may be used for disposable cassettes containing pneumatically actuated pumps and / or valves. As discussed above, if the number of pneumatically actuated pumps and / or valves in a cassette is large enough, the cassette containing these pumps and valves may become very large - and the pressures required may be very high - making it difficult to properly seal and position all of the pumps and valves. This difficulty may be alleviated by locating the valves and pumps in the primary cassette, from which the connecting tubes from the pneumatic ports lead, such that pneumatic communication is provided between the valves and pumps in the primary cassette and a small secondary tube support cassette with a pneumatic interface for each tube, as shown in FIG. 23. In this manner, accurate positioning and sealing of all of the pneumatic interfaces may be achieved more easily with a small tube support cassette than if pneumatic actuation had to be applied directly to the large primary cassette. Additionally or alternatively, in certain embodiments, the valves in the primary cassette may be ganged so that several valves may be actuated simultaneously through a single pneumatic interface on the tube support cassette and a single connecting tube between the pneumatic interface and the valves.

[0300] FIG. 26 shows an expanded view of the manifold interface 2500 shown in FIG. 25. The manifold interface 2500 includes, among other things, the probes 61, 62 and the pneumatic ports 2539a, 2539b. Referring again to FIG. 13B, it can be seen that the manifold 130 is mounted to the manifold interface 2500 such that the probes 61, 62 interface with the thermowells 133a, 133b, respectively, and the pneumatic ports 2539a, 2539b interface with the pneumatic interfaces 139a, 139b, respectively. The manifold interface 2500 further includes a data key interface 2540 that interfaces with a corresponding data key in the disposable unit. The data key interface 2540 preferably provides a two-way communication interface through which the controller 49 can read information (e.g., serial / model number, expiration date, and usage information) from the disposable unit and write information (e.g., usage information) to the disposable unit. In an exemplary embodiment, the controller 49 may prevent a procedure from starting if the data key is not present or if the disposable unit is unusable, for example because it contains an unacceptable serial / model number, is past a pre-set expiration date, or has already been used. The controller 49 may terminate a procedure if the data key is removed. Instead of a data key interface 2540, the base unit 11 or manifold interface 2500 may include other types of interfaces (e.g., RFID, barcode reader, smart key interface) to read and / or write information to the disposable unit.

[0301] It should be noted that one or more pumps (e.g., pump pods) may be integrated with a manifold, such as manifold 130, and disposed within the base unit as a single cartridge. The assembly may also include a pneumatic connection from a pneumatic port (connected to the base unit) directly to the pump actuation chamber, such that no external tubing is required to make a pneumatic connection to the pump pod. The assembly may also or alternatively include a fluid connection (e.g., from the pump outlet to an interface with the heat exchanger bag), such that no external tubing is required between the pump outlet and the manifold or bag.

[0302] 3.1.6. Exemplary Blood Warming Schematic 6 is a schematic diagram of the connection of the disposable unit 16, according to an exemplary embodiment of the present invention. After priming the disposable unit 16, an inlet catheter 67 and an outlet catheter 68 are inserted into the patient's blood vessel or vessels. Several patient temperature probes 66 are disposed on or in the patient. These probes 66 provide patient temperature information to the controller to monitor possible patient overheating.

[0303] The pump pods 25a, 25b - operated by the pneumatic actuation system of the base unit (under the control of the controller 49) through the pneumatic port 38 - draw blood from the inlet catheter 67 into the tubing of the disposable unit. The pump pods' inlet and outlet check valves 35, 36 ensure that the blood travels in the correct direction (i.e., clockwise in the schematic diagram shown in FIG. 6) through the tubing of the disposable unit. After exiting the pump pods 25a, 25b, the blood is pumped into a heat exchanger bag 21, which is preferably mounted between two warming plates in the base unit. Before the blood enters the warming area, the temperature is measured via a bag inlet temperature sensor 61, which transmits the temperature information to the controller 49. After warming, the temperature of the blood is measured again via a bag outlet temperature sensor 62, which also provides temperature information to the controller 49. The warmed blood then flows through the air trap / filter 29 and into the patient through the return catheter 68.

[0304] Preferably, the controller uses a closed loop control scheme to achieve / maintain patient temperature and to ensure that blood does not become locally overheated (even when patient temperature is at a safe level, blood can overheat in heat exchanger components if, for example, the heat exchanger is malfunctioning or blood is not pumped fast enough) based on, among other things, patient temperature information (e.g., received through the patient interface 2704), blood temperature information (e.g., received through a thermowell in the manifold 130 and corresponding sensors in the manifold interface 2500), and pump status information (e.g., reservoir pressure, working chamber pressure, end of stroke detection, volume measurement, air detection, occlusion detection, leak detection). In addition, the controller typically receives multiple patient temperature inputs. The controller may dynamically adjust operation of the heat exchanger and / or pump based on the patient temperature information and blood temperature information.

[0305] The bag inlet temperature sensor 61 and the bag outlet temperature sensor 62 may be permanently mounted in the base unit 11 near where the bag inlet and outlet are located. To improve thermal conductivity between the blood flowing within the bag and the temperature sensors located outside the bag, thereby increasing the accuracy of the temperature readings, the bag may include metallic thermowells at the bag inlet and outlet that extend into the blood flow path. When the bag is placed between the warming plates, the thermowells can accommodate and receive the temperature sensors 61, 62 extending from the base unit 11. As discussed below, the metallic thermowells can also be used as electrical conductors and therefore can be used to detect leaks in the bag 21 or air in the bag 21.

[0306] In the system shown in Figure 6, a priming tube 2021 may be provided to supply a priming fluid (e.g., water) to the pod pump. Additionally, an air purge / sample port 2019 may be provided to facilitate air purging and allow sampling of blood being returned to the patient. A blood monitoring interface may also be provided, including, for example, a bifurcated sensor connection (mating luer lock) 2020 and a disposable H / S cuvette 2022 for the CDI™ Blood Parameter Monitoring System 500 blood gas monitor sold by Terumo Cardiovascular Systems Corp.

[0307] In various alternative embodiments, the controller 49 may detect an abnormal condition in the system based on several factors, including (i) the difference between the bag inlet and bag outlet temperatures measured by the bag inlet and bag outlet sensors 61, 62, respectively, (ii) the volumetric flow rate of blood through the disposable unit 16, and (iii) the power being supplied to the warming plate of the base unit. If each pump pod 25a, 25b pumps the same known volume of blood during each pump stroke, the volumetric flow rate can be measured by simply measuring the number of pump strokes per time and multiplying that number by the volume pumped per stroke (the flow rate can be determined in this manner as long as a complete pump stroke is being performed. As discussed above, the controller in the preferred embodiment monitors whether a complete stroke is being performed by dithering the valving mechanism and analyzing pressure information from the actuation chamber pressure transducer). The product of the three factors - the measured flow rate, the measured blood temperature rise, and the specific heat of the blood - should be proportional to the power being supplied to the warming plate. If this balance changes significantly during a heating session, the controller preferably generates a warning signal. The warning signal can be used to alert a supervising medical technician or to stop direct heating action.

[0308] Preferably, the controller generates two estimates based on a given set of temperature and flow measurements, one based on all uncertainties biased towards one side and one based on all uncertainties biased towards the other side. The power being consumed by the heating plate should always be lower than one estimate and higher than the other estimate. If the power measurements fall outside this range, the controller preferably generates a warning signal.

[0309] However, the system may include other types of sensors and systems. For example, the system may also provide an anticoagulant to the patient, particularly to allow for prolonged treatment. The system may also provide additional fluids to the patient and may include a hydration sensor to detect patient dehydration, particularly due to the warming treatment. The system may also include a hemolysis sensor to monitor for excessive hemolysis. Some of these detections may involve conductivity detection using a thermowell / sensor or other mechanisms.

[0310] 3.1.7. Leak and Air Detection In certain embodiments, detection of leaks in the heat exchanger bag 21 may be accomplished by measuring the electrical conductivity between one or both of the thermowells 133a, 133b and one or both of the upper and lower warming plates 12, 14. As discussed above, the base unit 11 includes sensors 61, 62 that interface with the thermowells 133a, 133b to provide electrical connection between the base unit 11 and the disposable unit 16. The base unit 11 further includes electrical probes connected to each of the warming plates 12, 14, respectively, which are typically also electrically conductive. If there is a leak, the electrical conductivity between the thermowell and the warming plate should increase substantially (because the fluid passing through the leak generally conducts electricity better than the material of the bag). Normally, the resistance between the electrical probes contacting the thermowell and each of the electrical probes on the warming plates is very high, since the plastic material from which the bag is made is a relatively good insulator. However, when there is a leak, the liquid (e.g., blood) passing through the leak in the bag provides a good conductor of electricity. Thus, the resistance drops significantly when there is a leak. Thus, a controller in communication with these electrical probes measures the conductivity between the probes and generates an alarm signal when the conductivity increases by a certain amount.

[0311] Similarly, the metallic thermowell can also be used to detect air in the bag flow path. Since air is a poor conductor of electricity, the presence of air in the bag increases the resistance between the thermowell and the plate. Thus, the controller detects a decrease in conductivity between the plate and the thermowell, and if this decrease exceeds a certain amount, the controller preferably issues an error signal and preferably stops the heating process.

[0312] Additionally or alternatively, the system may include other types of sensors to detect leaks, for example, a carbon dioxide sensor to detect blood leaks. The carbon dioxide sensor would typically be placed in a suitable location, for example adjacent to the fluid flow path through which the blood passes, perhaps in a partially or completely enclosed space (e.g., in a heat exchanger with the door closed). The carbon dioxide detector could also be included in the base unit or in communication with a controller in the base unit.

[0313] 3.1.8. Patient temperature monitoring In a blood warming procedure, the patient's temperature must be carefully monitored to prevent the patient from overheating beyond safe limits. In certain embodiments, at least two separate temperature probes are positioned in the patient, e.g., one in the abdomen-bladder or rectum, in contact with the bladder or rectal wall-and one in the nasal passage, in contact with the posterior wall of the passage (patient temperature can be monitored with a single probe or three or more probes, and from other locations or in other ways, e.g., by monitoring the air exhaled by the patient). If both sensors are positioned correctly, the temperature readings of the two probes should be within a certain range. If the temperature readings from the two probes differ significantly from each other, the controller may issue a warning signal and / or abort the warming procedure. In preparation for a blood warming procedure, the readings of the two probes are compared to each other and may also be compared to normal patient temperature readings as the probes are inserted into the patient. If the two probes fall within a preset range of each other and within the range of normal patient temperature readings, the medical personnel positioning the probes will know when they are positioned correctly.

[0314] During the blood warming procedure, the method shown in Figure 19 is preferably used to ensure that the patient does not become dangerously overheated. At step 90, temperature readings from the abdominal and nasal probes are taken. At step 91, the readings are compared to one another. If the readings are outside of a preset range, a warning signal is generated indicating that there is an abnormal temperature reading. At step 92, a controller monitors the temperature readings from one of the two probes and compares them to a preset upper limit. If a reading exceeds this preset upper limit, a warning signal is generated indicating that the patient is becoming overheated.

[0315] As discussed above, the heat exchanger system controller may monitor the patient temperature using at least two temperature probes. In practice, the controller only requires a temperature reading from a single temperature probe. The second temperature probe essentially provides a comparison with the reading from the first temperature probe. Thus, in certain embodiments, a single temperature probe may be used to provide a patient temperature reading to the controller. In such embodiments, an operator may independently monitor the second temperature probe and manually abort the heating action if the two temperature readings do not sufficiently match.

[0316] User Interface 27 illustrates an exemplary user interface screen according to an exemplary embodiment of the present invention. The right hand side of the screen includes (from top to bottom) indicators corresponding to various stages of therapy (i.e., system standby, pre-check, priming, warm-up, sustain, cool, and end therapy) to display the current stage of treatment (in this example, "warm-up" is highlighted to indicate that therapy is currently in the warm-up stage), a stage progress indicator to indicate, for example, the time remaining or elapsed in the current stage, and various therapy control buttons including four control buttons used by the operator to control the therapy (e.g., pause treatment, stop treatment, start or resume treatment, and go to next stage). Note that the four control buttons prevent the operator from reverting to a previous stage. The left hand side of the screen allows the operator to tab through screens that provide patient information, status information, temperature graphs, flow rate graphs, and records.

[0317] 3.1.10 Alternative Heat Exchanger Embodiments In the above embodiment, the fluid is heated or cooled by passing it through a heat exchanger bag disposed between two plates of the heat exchanger. Of course, the present invention is in no way limited to the use of heat exchanger bags or plates. In alternative embodiments, the heat exchanger bag may be used with other types of heat exchangers (e.g., the heat exchanger bag may be rolled and placed in a tubular chamber or other types of heat exchangers, such as an oven, refrigerator, water bath, or radiator). Additionally or alternatively, other types of fluid conduits (e.g., a length of tubing, and / or a radiator) may be used with one or more plates. The heat exchanger may include heating and / or cooling capabilities. Indeed, the heat exchanger may include both heating and cooling capabilities so that the heat exchanger system can be used for both heating and cooling applications, either as part of the same treatment (e.g., so that blood can be heated for a warming treatment and then rapidly returned to normal temperature after the treatment) or as part of separate treatments (e.g., so that a base unit can provide a warming treatment to one patient and then a cooling treatment to another patient).

[0318] In certain alternative embodiments, the disposable unit is configured to include or use a length of tubing as a heat exchanger component. The length of tubing is preferably thin-walled lay-flat tubing, although other types of tubing can be used. The tubing is disposed within a radiator, which may be part of the disposable appliance (e.g., the radiator may be attached to a manifold so that the entire unit can be placed within the base unit), part of the base unit (e.g., the radiator may be integral with or attached to one of the heat exchanger plates), or a separate component, either disposable or reusable. In either case, the radiator preferably includes a passageway to receive the length of tubing.

[0319] FIG. 75 shows a radiator 8000 according to an exemplary embodiment of the invention. The radiator 8000 has a continuous passageway from a first opening 8001 to a second opening 8002. As shown in FIG. 76, the passageway is configured to receive a length of tube 8006 (e.g., a thin-walled lay-flat tube) such that one end of the tube protrudes from the opening 8001 and the other end of the tube protrudes from the opening 8002. The tube may be placed in the radiator by a user (particularly if the radiator is part of a base unit or another reusable component) or may be provided attached to the radiator (particularly if the radiator is part of a disposable unit). Radiators are typically made of a thermally conductive material such as a thermally conductive plastic or metal. In an exemplary embodiment, the radiator 8000 may be about 150 mm (6 inches) in diameter and about 50 mm (2 inches) in height.

[0320] In this embodiment, the passage includes inner and outer concentric loops (8003 and 8004, respectively) connected via a meander section 8005. In particular, this configuration allows both openings 8001, 8002 to be reached from along the outer edge of the radiator. If opening 8001 (leading to inner loop 8003) represents the fluid entry point and opening 8002 (leading to outer loop 8004) represents the fluid exit point, then fluid will flow in a clockwise direction through the tubes in inner loop 8003 and in a counterclockwise direction through the tubes in outer loop 8004 (using the orientation shown in FIG. 76). A meander section 8005 connects the two loops and reverses the flow direction. Note that the inner and outer loops 8003, 8004 and meander section 8005 are configured to avoid sharp or abrupt changes in fluid direction and thus avoid excessive shear or turbulence being imparted to the fluid. Furthermore, this arrangement of tubes (particularly the lay-flat tubes which expand when carrying pressurized fluid) and radiator provides efficient heat exchange because the tubes and radiator are in close contact and involve a large surface area.

[0321] As discussed above, the radiator 8000 may be provided as part of a disposable unit or as a separate component, in which case the radiator 8000 is typically placed in a suitably configured heat exchanger of the base unit. For example, the radiator 8000 may be placed between two plates of the heat exchanger (similar to how the heat exchanger bag is placed between the two plates in the various embodiments described above), in which case the heat exchanger may be configured to accommodate the radiator 8000 by moving the two plates further apart and / or using a special door hinge that allows the upper plate to lie flat against the top of the radiator. The lower plate may include guides (e.g., guide 8007 as shown in the top and front views of FIG. 77) or cylindrical walls (e.g., cylindrical wall 8008 as shown in the top and front views of FIG. 78) to facilitate placement of the radiator in the heat exchanger. Also as discussed above, the radiator may be part of the base unit. For example, as shown in FIG. 79, the radiator 8000 can be integrated with the lower plate 14.

[0322] Alternatively, some type of radiator may be used that does not have separate tubing, so that the fluid is conveyed directly through the passages of the radiator. Such radiators are typically disposable, but may be re-used, for example after cleaning and sterilization. Figure 80 shows a sealed radiator 8009 similar to the radiator 8000 described above, including two ports 8010, 8011 for receiving fluid connections, such as manifolds or tubing connections directly to one or more pumps. As with the radiator 8000 described above, the radiator 8009 may be part of a base unit, part of a disposable unit, or a separate component.

[0323] It should be noted that these embodiments are illustrative and are not intended to represent all types of heat exchanger components that may be used in heat exchanger systems of the types described herein.

[0324] 3.2. Localized hyperthermia-chemotherapy treatments 45 depicts a localized thermochemotherapy treatment system 2600 according to an exemplary embodiment of the invention. System 2600 is essentially a similar version of the above-described type of heat exchanger system in that it includes a base unit 2611, and a disposable unit 2601. As with the above-described systems, base unit 2611 includes a heat exchanger, a pneumatic control system, a controller, and a built-in user interface screen 2606. Disposable device 2601 (e.g., a cassette) includes two pump pods 2625a and 2625b, a single inlet 2602, a single outlet 2603, and a drug delivery interface 2604 (a syringe interface in this example, but alternative embodiments may include other types of interfaces, e.g., a luer port or a needle).

[0325] An exemplary embodiment of system 2600 is designed to circulate approximately 1-2 liters per minute while providing drug delivery and fluid drainage. System 2600 can be used for local or regional treatments, such as filling a body cavity (e.g., after tumor removal) with a warmed chemotherapy solution for a period of time and then emptying the cavity. System 2600 can also be used to circulate bodily fluids (e.g., blood) in a regionalized manner while adding drugs, such as to achieve hemostasis and circulate fluids in a body region (e.g., one lung).

[0326] In a typical application, the pump inlet 2602 may be in fluid communication with a fluid source (usually a separate reservoir, but fluid can also be drawn directly from the patient), and the pump outlet 2603 may be in fluid communication with the patient for pumping fluid from the fluid source to the patient. The fluid source reservoir or a separate container may be coupled to receive fluid drained from the patient. Thus, for example, a reservoir may be used to provide the source fluid and a separate container may be used to receive the drained fluid, or the same reservoir (which may be the patient) may be used to provide the source fluid and receive the drained fluid. The pump may be any fluid pump, including, but not limited to, a pod pump of the type described herein, or other types of diaphragm pumps or other fluid pumps. As the fluid is pumped to the patient, a drug or other fluid (e.g., one or more chemotherapy drugs) may be introduced into the fluid through the drug delivery interface 2604, for example, using an auto-injector or any automated or manual drug delivery device.

[0327] During such pumping, the temperature of the fluid is controlled and maintained at a predetermined temperature (e.g., about 37° C. or body temperature) throughout the process. Temperature control can be achieved using a temperature sensor in conjunction with a warmer. In certain embodiments, the temperature sensor can be of any of the types described herein. The temperature sensor can be located anywhere in the fluid path, and in preferred embodiments, anywhere in the fluid path outside the patient. The fluid can be heated in any manner, including but not limited to, induction or surface warming. The fluid can be heated in a reservoir or elsewhere along the fluid path.

[0328] In one exemplary embodiment, the patient inlet may be located within the patient's peritoneum. Fluids and drugs may be pumped into the patient until a threshold fluid pressure is reached or a threshold fluid volume is pumped into the patient, indicating completion of the fill phase. Fluid is typically retained within the patient for a period of time and then typically drained from the patient (e.g., by activating a variable impedance at the patient outlet). The fill / drain cycle may be repeated a predetermined number of times based on the patient's therapeutic needs.

[0329] In another exemplary embodiment, a portion of a patient (e.g., a patient's limb) may be isolated, for example, using a tourniquet or pressure cuff. Bodily fluid (e.g., blood) mixed with medication or other fluids may be circulated through the isolated area in a manner similar to that described above. Fluid temperature may be maintained using an in-line warmer.

[0330] FIG. 84 shows a fluid circuit according to an exemplary embodiment of the invention that may be used to provide a localized thermochemotherapy treatment. A reservoir stores the fluid to be delivered to the patient. In this example, the fluid is pumped through a warmer to the patient. In alternative embodiments, the fluid may be warmed in the reservoir and the in-line warmer may be omitted. In some embodiments, the fluid in the reservoir may contain a drug, while in other embodiments, fluid may be added via a pump or other means (e.g., another inlet to the fluid line). Fluid from the patient may be drained back into the reservoir or into some other container (or simply discarded). The volume of fluid being pumped and / or drained may be monitored in the reservoir, for example, using a capacitive level probe or other sensor.

[0331] FIG. 85 shows another fluid circuit including a balance chamber that may be used to provide localized thermochemotherapy treatment, according to an exemplary embodiment of the present invention. In this example, the fluid is warmed in a reservoir, and the volume of fluid in the reservoir is monitored using a capacitive level probe. Fluid is typically pumped to the patient through the upper balance chamber by control of appropriate valves, although fluid may also be pumped directly to the patient (i.e., bypassing the balance chamber) by control of appropriate valves. Fluid drained from the patient flows back to the reservoir through the lower balance chamber. The balance chamber serves to ensure that a constant volume of fluid is always flowing in and out of the patient.

[0332] 86 shows another fluid circuit including a balance chamber and a second pump that may be used to provide localized thermochemotherapy treatment, according to an exemplary embodiment of the present invention. In this example, the second pump is used to pump fluid from the upper balance chamber to the patient, which also serves to drain the fluid from the patient to the lower balance chamber. As in the previous embodiment, the fluid may be warmed in the reservoir or in the fluid line.

[0333] FIG. 87 shows a fluid circuit including an outflow valve that may be used to provide localized thermochemotherapy treatment, according to an exemplary embodiment of the present invention. In this example, the outflow valve may be controlled to control the amount of fluid entering or leaving the patient. For example, when the valve is in a closed state, fluid may be pumped into the patient, for example to fill the patient's cavities. The outflow valve may be partially or fully opened to allow fluid to flow out of the patient or to circulate fluid through the patient.

[0334] 4. Thermal / Conductivity Sensors Various embodiments of thermal and / or conductivity sensors are described that may be used in a wide variety of applications, including but not limited to measuring thermal / conductivity of fluids or in the context of heat exchanger systems.

[0335] 4.1. Thermowell In one exemplary embodiment, a thermowell is used to house a temperature sensing probe. The thermowell is in direct contact with the target medium (e.g., a liquid such as blood) while the sensing probe is not. Based on the thermal conductivity determined mainly by the thermodynamic properties of the thermowell and the construction manner of the sensing probe, the sensing probe can determine the properties of the target medium without directly contacting the target medium. The accuracy and efficiency of the sensor device arrangement depends on many factors, including but not limited to the construction materials and configuration of the probe and thermowell.

[0336] With reference to FIGS. 50A and 50B, two embodiments of a sensor device including a thermowell 5100 and a sensing probe 5102 are shown in relation to a fluid line 5108. In these embodiments, the thermowell 5100 is integrated into the fluid line 5108. However, in other embodiments, some of which are described below, the thermowell 5100 is not fully integrated into the fluid line 5108. That is, the thermowell 5100 may be made of a different material as compared to the fluid line 5108. In alternative embodiments, the thermowell 5100 is not integrated into the fluid line, but may be integrated into anything or nothing. For example, in certain embodiments, the thermowell 5100 may be integrated into a vessel, chamber, machine, protective sleeve, fluid pump, pump cassette, disposable unit, manifold, or other assembly, subassembly, or component. For purposes of explanation, an exemplary embodiment is described for illustrative purposes. This exemplary embodiment includes an embodiment in which the thermowell 5100 is in the fluid line. However, the sensor device and thermowell may also be used outside of fluid conduits.

[0337] Referring to Figure 50A, a side view is shown of a thermowell 5100 formed in a fluid conduit 5108 that provides a space 5104 through which the subject media flows, and a sensing probe 5102. Data from the sensing probe is transmitted using at least one lead 5106. An end view of Figure 50A is shown in Figure 50B.

[0338] In this embodiment, the thermowell 5100 is integral with the fluid conduit 5108. The total area of ​​the thermowell 5100 may vary. Varying the configuration of the thermowell 5100 changes variables including, but not limited to, the thermal conductivity properties of the thermowell 5100, and therefore changes the thermal transfer between the thermowell 5100 and the sensing probe 5102. As will be described in more detail below, the material composition of the thermowell 5100 is another variable in the sensor apparatus.

[0339] In one embodiment, the fluid conduit 5108 is made of a material having the desired thermal conductivity. The material may vary depending on the purpose and may be any material, including but not limited to any plastic, ceramic, metal or metal alloy, or combinations thereof.

[0340] 51A and 51B, in these embodiments, the fluid conduit 5108 and the thermowell 5100 are separate. In some embodiments, the fluid conduit 5108 and the thermowell 5100 are made from different materials.

[0341] 50A-50B and 51A-51B show relatively simple embodiments of the sensor device. Thus, in these embodiments, the sensing device includes a thermowell 5100 and a sensing probe 5102, where the thermowell is either integral with the fluid line 5108 as a continuous part or separate from the fluid line 5108. However, many embodiments of the sensor device are contemplated. Most of the various embodiments include variations in the materials and configurations of the thermowell 5100 and / or the sensing probe 5102. These variations are determined by many variables related to the intended use of the sensor device. Thus, the subject media and the constraints of the desired sensor, such as accuracy, time to result, and properties of the fluid flow and subject media, are merely examples of the various constraints that determine the embodiment used. In most instances, each variable will affect at least a portion of the embodiment of the sensor device.

[0342] Thus, many variables affect various embodiments of the sensor apparatus, including, but not limited to, 1) thermowell geometry, 2) material composition of the thermowell, 3) material composition of the sensing probe, 4) desired flow rate of the target medium, 5) length and width of the thermowell, 6) desired accuracy of the sensing probe, 7) wall thickness, 8) length and width of the sensing probe, 9) manufacturing cost, 10) target medium composition and properties including resistance to turbulence, 11) sensing probe geometry, and 12) desired read speed.

[0343] Thus far, various embodiments of the sensor device have been described. The descriptions are intended to provide information regarding the influence of variables on the design of embodiments of the sensor device. However, these are merely exemplary embodiments. Many more embodiments are contemplated and can be readily designed based on the intended use of the sensor device. Thus, variations in one or more of the partial list of variables above may result in variations in the embodiments of the sensor device.

[0344] 52A and 52B, two embodiments of a thermowell 5100 are shown as separate from the fluid conduit 5108. These embodiments show two different configurations of the thermowell 5100. In FIG. 52A, the configuration includes a long thermowell 5100. In FIG. 52B, the configuration of the thermowell 5100 is shorter. The length and width of the thermowell 5100 will affect the nature and accuracy of the thermal conductivity between the thermowell 5100 and the sensing probe 5102. Depending on the use of the sensor device, the configuration of the thermowell 5100 is a variable.

[0345] With reference to FIG. 52A, the elongated thermowell 5100 generally provides improved isolation between the target media temperature in the fluid conduit 5104 and the ambient temperature. While the configuration of the elongated thermowell 5100 shown in FIG. 52A may be more accurate, the embodiment shown in FIG. 52B may be sufficiently accurate for the purposes at hand. Thus, the length and width of the thermowell 5100 may be any length and width that has desired or acceptable accuracy characteristics. Of course, while the two extreme lengths are shown in these embodiments, any length is contemplated. The descriptions herein are intended to illustrate some of the effects of the variables.

[0346] 52A and 52B, the long thermowell 5100 shown in FIG 52A may have a stronger impact on the fluid flow of the subject media in the fluid conduit 5108 than the embodiment shown in FIG 52B. Of course, the length of the thermowell 5100 may also affect the turbulence of the fluid flow. Thus, the length and width of the thermowell 5100 may be varied to increase or decrease the impact on the fluid flow and fluid turbulence while mitigating other variables.

[0347] The shape of the thermowell 5100 is also a variable. Any desired shape is contemplated. However, the shape of the thermowell 5100, as well as other variables, will be determined in part based on the intended use of the sensor device. For purposes of illustration, an exemplary embodiment is described herein. However, the shapes in this exemplary embodiment are not meant to be limiting.

[0348] With reference to FIG. 53, for purposes of illustration, the thermowell 5100 is divided into three zones. The top zone 5402 communicates with a sensing probe (not shown). The middle zone 5404 provides a desired length for the thermowell 5100. As noted above, the length may determine the degree to which it projects into the fluid path. The length is determined in part by the desired performance characteristics, as discussed above. Additionally, the middle zone 5404 isolates the top zone 5402 from the atmosphere. The middle zone 5404 may serve to position, fasten or seal the thermowell 5100 to a fluid line (shown as 5108 in FIGS. 50A-50B).

[0349] The lower zone 5406 is not necessary in some embodiments (see FIG. 56K), and thus in these embodiments, the middle zone 5404 and the lower zone 5406 may be a single zone. However, in this exemplary embodiment, the lower zone 5406 is shaped to aid in press-fitting the thermowell into a region of the fluid conduit and may position and / or fasten the thermowell 5100 to the fluid conduit 5108. In other embodiments, the zone 5406 may be shaped to facilitate various joining methods (see FIGS. 56A-56J, 56L-56S).

[0350] Referring to FIG. 54, a cross-section of an exemplary embodiment of a thermowell 5100 is shown. The dimensions of this exemplary embodiment of the thermowell 5100 are length A of about 0.113 inches (range 0-0.379 inches), radius B of about 0.066 inches, and wall thickness C of about 0.003-0.009 inches. These dimensions are provided for illustrative purposes only. Depending on the variables of the sensing device and intended use, the dimensions of the thermowell 5100 may vary, and the various embodiments are not necessarily corresponding in size.

[0351] In some embodiments, the wall thickness is not uniform, i.e., the wall thickness varies at different locations in the thermowell. Although the embodiments are shown with different thicknesses at different locations, this is for illustrative purposes only. Various embodiments of the thermowell may incorporate different wall thicknesses corresponding to variables, and these different wall thicknesses may be combined in different ways depending on the desired characteristics of the sensing device. Thus, for example, an embodiment may use thick zones 5404 in conjunction with thin zones 5406, or vice versa. Alternatively, any other combination of "thin" and "thick" may be used. Furthermore, the terms used to describe wall thickness are relative. Any desired thickness is contemplated. Thus, the illustrated figures are for illustrative purposes and show two embodiments, but more are contemplated.

[0352] 55A and 55B, zone 5402 can be thicker or thinner as needed. Thinner zones 5402 generally provide faster detection times, among other variables, while thicker zones may be useful for harsh environments or where reduced sensor sensitivity is desired. Zone 5404 may be thicker to provide greater strength, among other variables, or thinner to provide greater atmospheric isolation, among other variables. Zone 5406 may be thin or thicker depending on the fastening method used.

[0353] In practice, the thermowell 5100 may be embedded in the fluid conduit 5108 as a separate entity. This is shown and described above with respect to FIGS. 51A-51B. Various embodiments may be used to embed the thermowell 5100 in the fluid conduit 5108. Although preferred embodiments are described herein, any method or process for embedding the thermowell 5100 in the fluid conduit 5108 may be used. With reference to FIGS. 56A-56S, various configurations for embedding the thermowell 5100 in the fluid conduit 5108 are shown. In these embodiments, the thermowell 5100 may be made of any material, including but not limited to plastic, metal, ceramic, or combinations thereof. The material may be determined in part by compatibility with the intended target media. In these embodiments, the fluid conduit 5108 may be made of plastic, metal, or any other material that is compatible with the target media.

[0354] Referring first to Figure 56A, the thermowell 5100 is shown press-fit into the fluid conduit 5108 using zone 5404 (shown in Figure 53). In Figure 56B, the thermowell 5100 is shown press-fit into the fluid conduit 5108 using zone 5406. Referring to Figure 56C, the thermowell 5100 is shown held in the fluid conduit 5108 using flexible tabs 5704 and also includes an O-ring. Referring to Figure 56D, the thermowell 5100 is shown inserted into the fluid conduit 5108 with an O-ring 5702. Thermowell 5100 is also shown in an alternative embodiment where zone 5406 of thermowell 5100 includes an O-ring groove. The O-ring groove can be cut, formed, milled, cast, or injection molded into the thermowell, or can be formed in thermowell 5100 in any other manner. Figure 56E shows an embodiment similar to that shown in Figure 56D, except that an O-ring groove is formed in zone 5406, rather than cut, molded, or cast as shown in Figure 56D.

[0355] Referring to Figure 56F, the thermowell 5100 is shown press-fitted into the fluid conduit 5108, with zone 5406 including flexibility that allows the edges of zone 5406 to deform the material of the fluid conduit 5108. Referring to Figure 56G, the thermowell 5100 includes a notch 5706 in zone 5406 that gives zone 5406 flexibility for assembly to the fluid conduit 5108. An O-ring 5702 is also provided. Although two notches are shown, more or fewer notches may be used in alternative embodiments.

[0356] Referring to Figure 56H, the embodiment shown in Figure 56F is shown with the addition of an O-ring 5702. Referring to Figure 561, the thermowell 5100 is shown insert molded into the fluid conduit 5108. Zone 5406 is formed to facilitate or enable assembly by insert molding.

[0357] FIG. 56J illustrates an embodiment in which the thermowell 5100 is heat staked 5708 to retain the thermowell 5100 within the fluid conduit 5108. In some embodiments of FIG. 56J, an O-ring 5710 is also included. In this embodiment, the O-ring 5710 has a rectangular cross-section. However, in alternative embodiments, the O-ring may have a circular or X-shaped cross-section. Similarly, in the various embodiments described herein that have an O-ring, the O-ring in these embodiments can have a circular, rectangular or X-shaped cross-section, or any desired cross-sectional shape.

[0358] 56K, the thermowell 5100 is held within the fluid conduit 5108 by an adhesive 5712. The adhesive can be any adhesive, but in one embodiment, the adhesive is a UV curable adhesive. In an alternative embodiment, the adhesive can be any adhesive that is compatible with the subject media. In this embodiment, the thermowell 5100 is shown without zone 5406.

[0359] 56L, there is shown a thermowell 5100 that has been ultrasonically welded to a fluid conduit 5108. Zone 5406 has been prepared to allow for ultrasonic welding to bond.

[0360] 56M, there is shown a thermowell 5100 that is insert molded into a fluid conduit 5108. Zone 5406 is a flange around which the plastic in the fluid conduit 5108 flows. In the embodiment shown, the flange is flat, but in other embodiments the flange may be bell-shaped or other shapes.

[0361] 56N, there is shown a thermowell 5100 held within a fluid conduit 5108 by a retention plate 5714 and fasteners 5716. An O-ring 5702 is also shown.

[0362] 56O-56P, there is shown an end view of a thermowell 5100 retained within a fluid conduit 5108 by a retaining ring 5718 (FIG. 56O), or in an alternative embodiment, by a clip 5720 (FIG. 56P). An O-ring 5702 is also shown.

[0363] Referring to Fig. 56Q, the embodiment of Fig. 56C is shown with an alternative embodiment of thermowell 5100. In this embodiment of thermowell 5100, what is shown in Fig. 53 as zone 5404 includes a taper that may facilitate alignment with a sensing probe, may increase isolation of zone 5402 from the atmosphere, and may improve flow characteristics within the fluid path. Thermowell 5100 is shown held within fluid conduit 5108 using flexible tabs 5704. An O-ring is also provided.

[0364] FIG. 56R illustrates the embodiment of FIG. 56J with an alternative embodiment of the thermowell 5100. The thermowell 5100 illustrated in this embodiment has a taper in zone 5404 that may facilitate alignment with a sensing probe, improve isolation from the atmosphere in zone 5402, and improve flow characteristics in the fluid path. Zone 5402 provides a hemispherical contact for effective thermal coupling with the thermal probe. The thermowell 5100 is heat staked 5708 to hold the thermowell 5100 within the fluid conduit 5108. In some embodiments of FIG. 56R, an O-ring 5710 is also included. In this embodiment, the O-ring 5710 has a rectangular cross-section. However, in alternative embodiments, the O-ring may have a circular or X-shaped cross-section.

[0365] Referring to Figure 56S, the embodiment of Figure 56H is shown with an alternative embodiment of thermowell 5100. Figure 56S is shown with the addition of O-ring 5702. In this embodiment of thermowell 5100, zone 5404 (as shown in Figure 53) has a convolution that may increase isolation of zone 5402 from the atmosphere. Although several configurations of zone 5404 are shown, many more may be shown to obtain desired performance characteristics.

[0366] 4.2. Detection Probes Referring to FIG. 57, a cross-sectional view of an exemplary embodiment of a sensing probe 5800 is shown. Housing 5804 is a hollow structure that continues to tip 5802. The tip is made of a highly thermally conductive material. In this exemplary embodiment, housing 5804 is made of a thermally insulating material. In some embodiments, the housing is made of a thermally insulating and electrically insulating material. In this exemplary embodiment, housing 5804 is made of a plastic, which is a thermally insulating and electrically insulating material. Tip 5802 directly contacts the subject medium or is mated with a thermowell.

[0367] In this exemplary embodiment, tip 5802 is attached to housing 5804 using a urethane or other insulating material between tip 5802 and housing 5804 (area 5807). The urethane provides additional structural support. In alternative embodiments, other processing and bonding methods can be used to bond tip 5802 to housing 5804.

[0368] The tip 5802 of the sensing probe 5800 is made of a thermally conductive material. However, more thermally conductive materials, such as copper, silver, and steel, may be used depending on the desired use of the sensing probe and the target medium. The material may be selected for durability and suitability for the intended use. Additionally, factors such as cost and ease of manufacture may determine the selection of other materials. In one exemplary embodiment, the tip 5802 is made of copper. In other embodiments, the material may be an alloy of copper or silver, or a solid or alloy of any thermally conductive material or element, including but not limited to metals and ceramics. However, in this exemplary embodiment, the tip 5802 is made of metal.

[0369] In this exemplary embodiment, tip 5802 is configured to thermally couple with a thermowell, as described above in the exemplary embodiment of the thermowell. In this exemplary embodiment, as well as other embodiments, tip 5802 may be configured to insulate thermal sensor 5808 from the atmosphere. In this exemplary embodiment, tip 5802 is made of metal.

[0370] In alternative embodiments, non-conductive materials may be used for the tip. These embodiments are preferred for applications where the thermowell needs to be electrically isolated from the probe. In another alternative embodiment, the tip 5802 may be made of any thermally conductive ceramic.

[0371] In this exemplary embodiment, the thermal sensor 5808 is located within the housing and is attached to the inside of the tip 5802 using a thermally conductive epoxy 5812. In this exemplary embodiment, the epoxy used is THERMALBOND, but in other embodiments, any thermal grade epoxy can be used. However, in alternative embodiments, thermal grease may be used. In alternative embodiments, no epoxy or grease is used.

[0372] The thermal sensor 5808 is a thermistor in this exemplary embodiment. Thermistors are generally a more accurate embodiment. However, in alternative embodiments, the thermal sensor 5808 may be a thermocouple or any other temperature sensing device. The choice of thermal sensor 5808 may again be related to the intended use of the sensing device.

[0373] Leads 5814 from the thermal sensor 5808 exit the back of the housing 5804. These leads 5814 connect to other equipment used in the calculations. In this exemplary embodiment, a third lead 5816 from the tip 5802 is also included. This third lead 5816 is attached to a tip of a tab 5818. In this embodiment, the tip 5802 is metal and the housing is plastic, so the third lead 5816 is attached to the tip 5802. In an alternative embodiment, the housing 5804 is metal, so the third lead 5816 may be attached to the housing 5804. Thus, in this exemplary embodiment, the tip 5802 includes a tab 5818 for attachment to a lead. However, in alternative embodiments, and perhaps depending on the intended use of the sensing device, the third lead 5816 may not be included. Additionally, in alternative embodiments where a third lead is not required, the tip 5802 may not include the tab 5818. Referring to FIG. 58, an exploded view of a sensing probe 5800 is shown.

[0374] Referring to Figure 59, an alternative embodiment of this exemplary embodiment is shown. In this embodiment, a sensing probe tip 6002 is shown. The tip 6002 includes a zone 6004 that will contact the target medium to be tested, or a thermowell. Zone 6006 leads to a sensing probe housing (not shown). An interior region 6008 houses a thermal sensor (not shown). In this embodiment, the tip 6002 is made of stainless steel. However, in other embodiments, the tip 6002 can be made of any thermally conductive material, including but not limited to metal (including copper, silver, steel and stainless steel), ceramic or plastic.

[0375] In this exemplary embodiment, the zone 6006 includes a tab 6010. From the tab 6010, a third lead (such as 5816 described with respect to FIG. 57) leads. Referring now to FIGS. 60A and 60B, a sensing probe 6000 is shown including a tip 6002 and a housing 6012. In one embodiment, the housing 6012 is made of any insulating material, including but not limited to plastic. In one embodiment, the housing 6012 is press-fit, glued, or attached in any other manner to the tip 6002. In one embodiment, the thermal sensor 6014 is thermally coupled to the tip 6002 using a thermal grade epoxy, or in an alternative embodiment, using a thermal grease 6022. Two leads 6016 from the thermal sensor 6014 extend to the distal end of the housing. In some embodiments, a third lead 6018 is attached from the tab 6010 to the tip 6002. As discussed above, in some embodiments where a third lead is not required, the tip 6002 does not include the tab 6010.

[0376] 60B, there is shown an alternative embodiment of the sensing probe 6000. In this embodiment, the housing 6012 is plastic molded over the zone 6006 of the tip 6002 and the leads 6016 and, in some embodiments, the third lead 6018.

[0377] Referring to Figure 61, there is shown a general side view of one embodiment of the sensing probe 6000 shown in Figures 59-60B. The sensing probe 6000 includes a housing 6012, a tip 6002 and leads 6016, 6018. A flange 6020 is shown. In some embodiments, the flange 6020 is used for mounting and / or attachment to an instrument.

[0378] Referring to Figure 62A, the sensing probe 6000 shown in Figures 59-61 is shown coupled to a thermowell 5100 fastened to a fluid conduit 5108. In the illustrated embodiment, two leads 6016 are shown at the distal end of the sensing probe 6000. Additionally, in some embodiments, a third lead 6018 is incorporated into the sensing probe 6000. Figure 62B shows an alternative embodiment in which the sensing probe 6000 includes two leads 6016 but no third lead 6018.

[0379] 62A and 62B, the tip 6002 of the sensing probe 6000 is in direct contact with the thermowell 5100. Referring again to FIG. 53 and further to FIGS. 62A and 62B, the thermowell 5100 includes a zone 5402. The thermowell 5100 is hollow and an inner portion of the zone 5402 is shaped for mating contact with the sensing probe tip 6002. As shown in this embodiment, the thermowell 5100 is designed to have a configuration that mates with the sensing probe 6000. Thus, the configuration of the thermowell 5100 is determined by the configuration of the tip 6002 of the sensing probe 6000 and vice versa. In some embodiments, it may be desirable for the sensing probe 6000 not to fit snugly or tightly into the thermowell 5100.

[0380] Referring to Figure 63A, one embodiment of a sensing probe 5800 (as shown in Figure 57) is shown coupled to a thermowell 5100 fastened within a fluid conduit 5108. In the illustrated embodiment, two leads 5814 are shown at the distal end of the sensing probe 5800. In some embodiments, a third lead 5816 is also incorporated into the sensing probe 5800. Figure 63B shows an alternative embodiment in which the sensing probe 5800 includes two leads 5814 but does not include the third lead 5816.

[0381] 63A and 63B, the tip 5802 of the sensing probe 5800 is in direct contact with the thermowell 5100. Referring again to FIG. 53 and further to FIG. 63A and 63B, the thermowell 5100 includes a zone 5402. The thermowell 5100 is hollow and an inner portion of the zone 5402 is shaped for mating contact with the sensing probe tip 5802. As shown in this embodiment, the thermowell 5100 is designed to have a configuration that mates with the sensing probe 5800. Thus, the configuration of the thermowell 5100 is determined by the configuration of the tip 5802 of the sensing probe 5800 and vice versa.

[0382] 4.3. Sensor device For the purposes of describing the sensor device, the sensor device will be described with respect to an exemplary embodiment. This exemplary embodiment is shown in Figures 62A, 62B and 64, with an alternative exemplary embodiment shown in 63A and 63B. In an alternative embodiment of the sensor device, the sensing probe can be used outside the thermowell. However, the sensor device has already been described alone in this specification. Therefore, the following description describes one embodiment of an exemplary embodiment of the sensor device including a sensing probe and a thermowell for this purpose.

[0383] Referring to Figure 64, an exemplary embodiment shows the sensing probe 6000 and thermowell 5100 shown in Figure 62A coupled and external to the fluid conduit. As noted above, the thermowell 5100 may be in the fluid conduit, protective sleeve, any disposable device, machine, chamber, cassette, or container. However, for purposes of this description of the exemplary embodiment, the thermowell 5100 is anywhere (Figure 62A) that is used to determine the thermal and / or conductive properties of the subject media.

[0384] The subject media is in contact with the outside of zone 5402 of the thermowell 5100. Thermal energy is transferred from the subject media to the thermowell 5100 and further to the tip 6002 of the sensing probe 6000. The thermal energy is then conveyed to the thermal sensor 6014. The thermal sensor 6014 communicates via lead 6016 with an instrument capable of determining the temperature of the subject media based on feedback from the thermal sensor 6014. In embodiments where conductivity sensing is also desired, lead 6018 communicates with an instrument capable of determining the conductivity of the subject media. For determining the conductivity of the subject media, a second electrical lead / contact (not shown) is used in addition to lead 6018. The second lead can be a second sensor device as shown in FIG. 64 or a second probe not necessarily the same as the sensor device shown in FIG. 64, but rather any probe or device including electrical contacts capable of sensing the electrical capacitance of the subject media.

[0385] Heat transfer from the tip 6002 to the thermal sensor 6014 may be enhanced through the use of thermal epoxy or thermal grease 6022 .

[0386] 63A and 63B, in this alternative exemplary embodiment, a sensing probe 5800 is coupled to the thermowell 5100 with a tip 5802 having the configuration shown forming a gap 6402 between the tip 5802 and the inner zones 5404 and 5406 of the thermowell 5100. The gap 6402 provides an insulating barrier such that only the top of the sensing tip of 5802 communicates with the upper zone 5402 of the thermowell 5100.

[0387] The sensing probe 5800 and thermowell 5100 are shown coupled and outside the fluid line. As noted above, the thermowell 5100 may be in a fluid line, a protective sleeve, a disposable unit, a machine, a non-disposable unit, a chamber, a cassette, or a container. However, for purposes of this description of the exemplary embodiment, the thermowell 5100 is anywhere that is used to determine the thermal and / or conductive properties of the subject media (FIG. 63A).

[0388] The subject media is in contact with the outside of zone 5402 of the thermowell 5100. Thermal energy is transferred from the subject media to the thermowell 5100 and further to the tip 5802 of the sensing probe 5800. The thermal energy is then conveyed to the thermal sensor 5808. The thermal sensor 5808 communicates via lead 5814 with an instrument capable of determining the temperature of the subject media based on feedback from the thermal sensor 5808. In embodiments where conductivity sensing is also desired, lead 5816 communicates with an instrument capable of determining the conductivity of the subject media. For determining the conductivity of the subject media, a second electrical lead (not shown) is used in addition to lead 5816. The second lead can be a second sensor device as shown in FIG. 63A or a second probe not necessarily the same as the sensor device shown in FIG. 63A, but rather any probe or device including electrical contacts capable of sensing the electrical capacitance of the subject media.

[0389] Heat transfer from the tip 5802 to the thermal sensor 5808 may be enhanced through the use of thermal epoxy or thermal grease 5812.

[0390] 65, an alternative embodiment is shown showing a sensing probe 6602 coupled to a thermowell 5100. For purposes of this description, any embodiment of the sensing probe 6602 and any embodiment of the thermowell 5100 can be used. In this embodiment, thermal grease 6604 is present at the interface of the tip of the sensing probe 6602 and the inner zone 5402 of the thermowell 5100 to enhance thermal coupling between the tip of the sensing probe 6602 and the thermowell 5100. In one embodiment, the amount of thermal grease 6604 is just enough to fit into zone 5402. However, in alternative embodiments, a greater or lesser volume of thermal grease can be used.

[0391] 4.4. Sensor device system Referring to Fig. 66, a sensor device system is shown. In this system, the sensor device is shown in an instrument containing a fluid conduit 5108. The sensor device includes a sensing probe 6000 and a thermowell 5100. In this embodiment, the thermowell 5100 and the fluid conduit 5108 are the disposable parts and the sensing probe 6000 is the reusable part. The reusable part also includes a spring 6700. The spring 6700 and the sensing probe 6000 are located in a housing 6708. The housing 6708 can be in any machine, container, instrument, or other. The spring 6700 is a conical, coil spring, wave spring, or urethane spring.

[0392] In this embodiment, the thermowell 5100 and the sensing probe 6000 may include alignment features 6702, 6704 to aid in aligning the thermowell 5100 and the sensing probe 6000. Correct orientation of the thermowell 5100 and the sensing probe 6000 may aid in mating of the thermowell 5100 and the sensing probe 6000. The configuration of the space 6706 provides space for lateral movement for the sensing probe 6000. This allows the sensing probe 6000 to move laterally if necessary to align with the thermowell 5100 for mating.

[0393] The sensing probe 6000 is suspended by a spring 6700 supported by a flange 6020. The spring 6700 allows for vertical movement of the sensing probe 6000 as the thermowell 5100 mates with the sensing probe 6000. The spring 6700 helps establish intimate contact between the sensing probe 6000 and the thermowell 5100. The fluid conduit 5108 may be in any machine, vessel, instrument, or the like. The fluid conduit 5108 contains a fluid line 5104. The subject media flows through the fluid line 5104 and the thermowell 5100 located within the fluid conduit 5108 in sufficient contact with the fluid line 5104 to sense the temperature and, in some embodiments, conductivity properties of the subject media. The location of the thermowell 5100 within the fluid line 5104 may depend on the accuracy desired, the subject media, and other considerations, as discussed in detail above.

[0394] The assembly of the spring 6700 and the sensing probe 6000, together with the space 6706 within the housing 6708, can aid in the alignment of the sensing probe 6000 and the thermowell 5100 for mating, which provides thermal contact such that the thermowell 5100 and the sensing probe 6000 are thermally coupled.

[0395] A wire 6710 is shown. The wire contains leads. In some embodiments, there are two leads. Some of these embodiments are for temperature sensing. In other embodiments, the wire contains three or more leads. Some of these embodiments are for temperature and conductivity sensing.

[0396] Referring to FIG. 67, an alternative embodiment of the system shown in FIG. 66 is shown. In this embodiment, the sensing probe 6000 is suspended by a coil spring 6800. A retaining plate 6802 holds the coil spring 6800 to hold the spring 6800 and the sensing probe 6000. In one embodiment, the retaining plate 6802 is attached to the housing 6708 using screws. However, in alternative embodiments, the retaining plate 6802 is attached to the housing 6708 by any fastening method including, but not limited to, adhesives, flexible tabs, press fit, and ultrasonic welding. An alignment feature 6806 on the housing 6708 helps align the sensing probe 6000 with a thermowell (not shown). A gap in area 6808 in the housing 6708 allows for lateral movement of the sensing probe 6000. A wire 6710 is shown. The wire contains a lead. In some embodiments, there are two leads. Some of these embodiments are temperature sensing. In other embodiments, the wire contains three or more leads. Some of these embodiments are for temperature and conductivity sensing.

[0397] Referring to FIG. 68, the sensing probe 6000 is shown within the housing 6708. In these embodiments, a flexible member 6900, an alternative embodiment of a spring, is integrated with the sensing probe 6000 to allow vertical movement of the sensing probe 6000 within the housing 6708. A retaining plate 6902 grips the flexible member 6900 to hold the flexible member 6900 and the sensing probe 6000. In one embodiment, the retaining plate 6902 is attached to the housing 6708 using screws. However, in alternative embodiments, the retaining plate 6902 is attached to the housing 6708 by any fastening method including, but not limited to, adhesives, flexible tabs, press fit, and ultrasonic welding. Lateral movement of the sensing probe 6000 is achieved by a gap in the housing 6708 at region 6908. A wire 6710 is shown. The wire contains a lead. In some embodiments, there are two leads. Some of these embodiments are temperature sensing. In other embodiments, the wire contains three or more leads. Some of these embodiments are for temperature and conductivity sensing.

[0398] Referring to FIG. 69, an alternative embodiment of the sensing probe 6000 in a housing 7002 is shown. In this embodiment, a flexible member 7000 is attached to or is part of the housing 7002 and provides vertical movement of the sensing probe 6000. In this embodiment, openings 7004, 7006 in the housing 7002 are sized to limit lateral movement of the sensing probe 6000. The flexible member 7000 acts on a flange 7008 on the sensing probe 6000. A wire 6710 is shown. The wire contains leads. In some embodiments, there are two leads. Some of these embodiments are temperature sensing. In other embodiments, the wire contains three or more leads. Some of these embodiments are for temperature and conductivity sensing.

[0399] The flange can be located in any area on the sensing probe 6000 as shown and described with respect to Figures 61, 66, and 69. In other embodiments, the sensing probe may be aligned and positioned with other housing configurations. Thus, the housing embodiments shown herein are only some of the housing embodiments in which the sensor device may be used. The sensor device generally depends on being adequately positioned relative to the subject media. The configuration that achieves this may vary depending on the subject media and the intended use of the sensing device. Additionally, in some embodiments that do not use a thermowell and only use a sensing probe, further housing configurations may differ.

[0400] In some embodiments, the sensing device is used to sense conductivity, which in some embodiments is in addition to temperature sensing. In those embodiments where temperature and conductivity sensing is desired, the sensing probe typically includes at least three leads, two of which may be used for temperature sensing and a third lead for conductivity sensing.

[0401] Referring to FIG. 70, at least two sensors 7102, 7104 are located in an area containing a subject medium for conductivity sensing. In the illustrated embodiment, the area containing the subject medium is a fluid path 5104 in a fluid conduit 5108. The conductivity sensors 7102, 7104 may be one of the various sensing probe embodiments as described above, or one of the sensor device embodiments (including thermowells) as described above. However, in other embodiments, only one of the sensors is one of the sensor device embodiments or one of the sensing probe embodiments, and the second sensor is any electrical sensor known in the art. Thus, in the systems described herein, conductivity and temperature can be sensed using one of the sensor devices or one of the sensor probes as described herein and a second capacitive sensor, or one of the sensor devices or one of the sensor probes as described herein and an e...

Claims

1. a pump chamber plate (4340) having a pump chamber housing (4342) for a pod pump (4310) of a pod pump cassette, the pump chamber housing including an integral fluid path (4344), the integral fluid path fluidly connecting with an external fluid path (4346) defined at least in part by the pump chamber plate; the pod pump cassette further comprises an actuation plate (4320) and a middle plate (4330), the pump chamber plate being spaced from the actuation plate by the middle plate; the pod pump includes two valves fluidly connecting the pump chamber housing to the external fluid path; The actuation plate (4320) includes a pod pump actuation chamber housing (4312) and two valve actuation housing portions (4314) of the pod pump; said intermediate plate carrying a pump diaphragm (4332) and two valve diaphragms (4334), each of said two valve diaphragms being associated with a corresponding one of said two valves; the pump diaphragm (4332) together with at least the pump chamber housing (4342) defines a pump chamber (3406) of the pod pump; the integral fluid path extends beyond the pump diaphragm when the pump diaphragm is fully expanded and contacting the pump chamber housing such that the integral fluid path remains in fluid communication with both the pump chamber and the external fluid path when the pump diaphragm is fully expanded and contacting the pump chamber housing. Pod Pump Cassette (4300).

2. the pump diaphragm defines, together with at least the pod pump actuation chamber housing (4312) of the actuation plate (4320), an actuation chamber (3410) of the pod pump; the pump diaphragm is adapted to be actuated by actuation fluid flowing through an actuation port of the pod pump actuation chamber housing; each of the two valve diaphragms (4334) defines, together with at least a valve actuation housing portion corresponding to an actuation plate of the corresponding valve of the two valves, a valve actuation chamber of the corresponding valve of the two valves; each of the two valve diaphragms is adapted to be actuated by actuation fluid flowing through an actuation port of the valve actuation housing portion corresponding to the actuation plate of the corresponding one of the two valves; the pod pump cassettes are adapted to be modularly connected to respective valve actuation chambers and machinery adapted to individually control the valve actuation chambers of the pod pumps; 2. The pod pump cassette of claim 1.

3. the pump chamber plate and the actuation plate are connected to the intermediate plate by laser welding, solvent bonding, heat welding, electromagnetic welding, resistance welding, RF welding, ultrasonic welding, adhesives, screws, bolts, press fits, snap fits, or clamps; 2. The pod pump cassette of claim 1.

4. The working fluid is a gas.

3. The pod pump cassette of claim 2.

5. The pump diaphragm (4332) is preformed such that at least a portion of the pump diaphragm is dome-shaped.

2. The pod pump cassette of claim 1.

6. the pump diaphragm (4322) facing the pump chamber (3406) comprises rings, protrusions, ribs, bars, dimples, bumps or dots; 2. The pod pump cassette of claim 1.

7. The pump diaphragm (4332) is preformed with a thick-walled ring at its outer diameter.

2. The pod pump cassette of claim 1.

Images