Continuous-flow centrifuge chambers having non-uniform radius high-g wall

Abstract

To provide continuous-flow centrifuge chambers having a non-uniform radius high-G wall.SOLUTION: Fluid separation chambers are provided with a central hub 56, and a low-G wall 58 and a high-G wall 60 that are generally annular and extend about the central hub to define therebetween a separation channel 66. Multiple radial walls 70, 72 extend from the hub to the channel to define an inlet passage 68, two outlet passages 74, 76, and a terminal wall 70 separating an upstream end of the separation channel from a downstream end of the channel. The radius of the high-G wall is greater at the downstream end than at the upstream end of the separation channel, which may include the radius gradually increasing along a tapered section of the high-G wall. The tapered section may extend from the upstream end of the separation channel to the downstream end of the channel or along a smaller length of the channel. The radius of the low-G wall may similarly increase from the upstream end of the separation channel to the downstream end.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] [Cross - Reference to Related Applications] This application claims the benefit of priority of U.S. Provisional Patent Application No. 63 / 314,787, the content of which is incorporated herein by reference.

[0002] [Technical Field] The present disclosure relates to continuous - flow centrifuges. More specifically, the present disclosure relates to a continuous - flow centrifuge chamber having a high - G wall of non - uniform radius.

Background Art

[0003] Currently, various blood - processing systems enable the collection of specific blood components rather than whole blood from a blood source. Typically, in such systems, whole blood is drawn from a source, specific blood components or constituents are removed and collected, and the remaining blood components are returned to the source.

[0004] Whole blood is usually separated into its components by centrifugation. For this, after whole blood is drawn from a source, it needs to pass through a centrifuge before being returned to the source. To avoid the possibility of contamination and infection of the source, it is preferable that the blood be contained within a closed, sterile fluid - flow circuit throughout the centrifugation process. Thus, a typical blood - processing system includes a permanent and reusable centrifuge assembly that includes hardware (such as a drive system, pumps, valve actuators, programmable controllers, etc.) for rotating and pumping the blood, and a disposable, sealed and sterilized fluid - flow circuit mounted to cooperate with the hardware. The centrifuge assembly engages and rotates the disposable centrifuge chamber of the fluid - flow circuit during the collection procedure. However, only the fluid - flow circuit actually contacts the blood, and this assembly is used only once and then discarded.

[0005] When whole blood is rotated in a centrifuge, heavier (higher specific gravity) components, such as red blood cells, move radially outward from the center of rotation towards the outer wall or "high g" wall of the separation chamber. Lighter (lower specific gravity) components, such as plasma, move towards the inner wall or "low g" wall of the separation chamber. Various components of these can be selectively removed from the whole blood by forming appropriately positioned channeling seals and outlet ports within the separation chamber.

[0006] This type of centrifuge chamber is well known, and representative centrifuge chambers are described in U.S. Patent No. 9,327,296 and PCT application International Publication No. WO2018 / 053217A1, both disclosures of which are incorporated herein by reference. While conventional centrifuge chambers have proven suitable for the separation of blood and other biological fluids, it would be advantageous to provide a chamber that improves upon the performance and / or manufacturability of such known chambers. [Overview of the Initiative]

[0007] There are several embodiments of the subject matter that can be embodied separately or together in the apparatus and systems described and claimed below. These embodiments may be used individually or in combination with other embodiments of the subject matter described herein, and the joint description of these embodiments is not intended to preclude the use of these embodiments separately or the claim of such embodiments separately or as sets in different combinations in the claims attached herein.

[0008] In one embodiment, a fluid separation chamber rotating around an axis includes a central hub coincident with the axis. A substantially annular low-G wall and a substantially annular high-G wall extend spaced apart around the central hub, defining a separation channel between them, with an upstream end and a downstream end. Multiple radial walls extend from the central hub to the separation channel, defining a terminal wall separating the upstream end of the separation channel from the downstream end, an inlet passage at the upstream end of the separation channel, and low-G and high-G outlet passages. The high-G wall has a larger radius at the downstream end of the separation channel than at the upstream end at each axial position.

[0009] These and other aspects of this subject matter are described in the following detailed description of the attached drawings. [Brief explanation of the drawing]

[0010] [Figure 1] This is a perspective view of an exemplary fluid processing apparatus comprising components of a fluid processing system according to one aspect of the present disclosure.

[0011] [Figure 2] This is a schematic diagram of an exemplary disposable fluid flow circuit that can be attached to the fluid processing apparatus of Figure 1 to complete a fluid processing system according to one aspect of the present disclosure.

[0012] [Figure 3] Figure 1 is a perspective view of an exemplary centrifuge in a fluid processing apparatus, with the centrifugation chamber of the fluid flow circuit installed inside.

[0013] [Figure 4] Figure 1 is a plan view of an exemplary cassette of a fluid flow circuit that can be operated to perform various different fluid processing procedures in relation to the fluid processing apparatus shown.

[0014] [Figure 5] Figure 3 is a perspective view of the centrifuge, with a selected portion broken to show the light source of the interface monitoring assembly.

[0015] [Figure 6] It is a perspective view of the centrifuge of FIG. 3, and the light source operates to send a light beam to the photodetector of the interface monitoring assembly.

[0016] [Figure 7] It is a perspective view of the centrifuge of FIG. 3, and a selected portion thereof is broken away to show the light source and the photodetector of the interface monitoring assembly.

[0017] [Figure 8] It is a perspective view of an exemplary centrifuge chamber of the fluid flow circuit of FIG. 2.

[0018] [Figure 9] It is a perspective view of a fluid flow path or separation channel of a conventional configuration that can be defined by the centrifuge chamber of FIG. 8.

[0019] [Figure 9A] It is a bottom view of the separation channel of FIG. 9.

[0020] [Figure 10] It is a bottom view of a fluid flow path or separation channel that can be defined by the centrifuge chamber of FIG. 8 according to one aspect of the present disclosure.

[0021] [Figure 10A] It shows the separation channel of FIG. 10 superimposed on the separation channel of FIG. 9A.

[0022] [Figure 11] It is an enlarged perspective view of a part of the channel of the centrifuge chamber of FIG. 8, and the interface between the separated fluid components is disposed at a desired position (typically) on the inclined portion defined in the channel.

[0023] [Figure 12] It is an enlarged perspective view of the channel and the inclined portion of FIG. 11, and the interface is at an undesirably high position (typically) on the inclined portion.

[0024] [Figure 13] Figure 11 is an enlarged perspective view of the channel and inclined section, where the interface is located at an (typically) undesirable low position on the inclined section.

[0025] [Figure 14] Figure 8 is a perspective view of a prism reflector used in combination with the centrifugal separator.

[0026] [Figure 15] Figure 14 is a perspective view of the prism reflector, showing the transmitted light. [Modes for carrying out the invention]

[0027] The embodiments disclosed herein are intended to provide a description of the subject matter, and it should be understood that the subject matter can be embodied in various other forms and combinations not shown in detail. Accordingly, specific designs and features disclosed herein should not be construed as limiting the subject matter as defined in the appended claims.

[0028] Figures 1-15 show components of blood or fluid processing systems embodying various aspects of this subject matter. While the system can be described herein in relation to its use in separating blood into two or more components, it should be understood that the system described herein can be used to process a variety of biological fluids or body fluids (including fluids containing both body and non-body fluids, such as anticoagulated blood) and non-body fluids.

[0029] The fluid processing systems described herein typically include two main components: a durable and reusable fluid processing device 10 (Figure 1) and a disposable fluid flow circuit 12 (Figure 2). The illustrated fluid processing device 10 includes a rotating membrane separator drive unit 14 (Figure 1), a centrifuge or centrifugal separator 16 (Figure 3), additional components that control the fluid flow through the disposable flow circuit 12, and a control unit 18 (Figure 1). The control unit 18 manages the operation of the other components of the fluid processing device 10 to perform a procedure selected by the operator. The principles described herein regarding setting the rotational speed of a continuous flow centrifugal separator are not limited to a particular fluid processing system or procedure, and therefore a complete fluid processing device or procedure will not be described in detail herein. However, for a detailed description of the fluid processing device 10 in Figure 1, refer to the PCT patent application International Publication No. WO2018 / 053217A1, along with various exemplary procedures that can be performed using such a system.

[0030] I. Durable fluid processing equipment The fluid processing apparatus 10 (Figure 1) is configured as a durable item capable of long-term use. It should be understood that the fluid processing apparatus 10 in Figure 1 is merely an example of one possible configuration, and the fluid processing apparatus according to this disclosure may have different configurations. For example, omitting the rotary membrane separator drive unit 14 in the fluid processing apparatus is within the scope of this disclosure.

[0031] In the illustrated embodiment, the fluid processing apparatus 10 is embodied in a single housing or case 20. The illustrated case 20 includes a substantially horizontal portion 22 (which may include inclined or angled surfaces or top surfaces to improve visibility and ergonomics) and a substantially vertical portion 24. The rotating membrane separator drive unit 14 and the centrifuge 16 are shown as being incorporated into the substantially horizontal portion 22 of the case 20, and the control unit 18 is shown as being incorporated into the substantially vertical portion 24.

[0032] A. Rotating membrane separation drive device The illustrated fluid processing apparatus 10 includes a rotor support or a rotary membrane separator drive unit 14 (Figure 1) for housing a substantially cylindrical rotary membrane separator 26 of a fluid flow circuit 12 (Figure 2). U.S. Patent No. 5,194,145 (incorporated herein by reference) describes an exemplary rotary membrane separator drive unit suitable for incorporation into the fluid processing apparatus 10; however, it should be understood that the rotary membrane separator drive unit 14 can be configured in different ways without departing from the scope of this disclosure. Because the principles described herein are specific to the configuration of the chamber 32 received by the centrifuge 16, the rotary membrane separator drive unit 14 is not described in detail herein.

[0033] B. Centrifugal separator The illustrated centrifuge 16 includes a centrifugal chamber 34 (Figure 3) that can accommodate other components of the centrifuge 16. The centrifugal chamber 34 may include a lid 36 that is opened to insert and remove the centrifugal chamber 32 of the fluid flow circuit 12. During the separation procedure, the lid 36 can be closed with the centrifugal chamber 32 positioned inside the centrifugal chamber 34 as the centrifugal chamber 32 rotates or oscillates around the shaft 38 under the power of the electric drive motor or rotor 40 of the centrifuge 16.

[0034] The specific configuration and operation of the centrifuge 16 depend on the specific configuration of the centrifugal chamber 32 of the fluid flow circuit 12. In one embodiment, the centrifuge 16 is similar in structure and operation to the ALYX® processing apparatus manufactured by Fenwall, Incorporated, Lake Zullick, Illinois, an affiliate of Fresenius Kaby AG, Bad Homburg, Germany, as described in detail by U.S. Patent No. 8,075,468, incorporated herein by reference. More specifically, the centrifuge 16 may include a carriage or support 42 that holds the centrifugal chamber 32 and a yoke member 44. The yoke member 44 engages with the umbilix 46 of the fluid flow circuit 12, and it extends between the centrifugal chamber 32 and the cassette 48 of the fluid flow circuit 12 (Figure 4). The yoke member 44 causes the umbilix 46 to orbit around the centrifugal chamber 32 at a rotational speed of 1ω. As the Unbilix 46 orbits the centrifugal chamber 32, it twists around its own axis. The twist of the Unbilix 46 around its axis when it rotates with the yoke member 44 at 1ω imparts a rotation of 2ω to the centrifugal chamber 32, according to known designs. The relative rotation of the yoke member 44 at a rotational speed of 1ω and the centrifugal chamber 32 at a rotational speed of 2ω keeps the Unbilix 46 untwisted and avoids the need to rotate the seal.

[0035] The fluid is introduced into the centrifuge chamber 32 by the Unbilix 46, and within the centrifuge chamber 32, the fluid is separated as a result of the centrifugal force as it rotates (for example, into a layer of less dense components, e.g., platelet-rich plasma if the fluid is blood, and a layer of denser components, e.g., concentrated red blood cells if the fluid is blood). Components of the interface monitoring assembly may be located within the centrifuge compartment 16 to monitor the separation of the fluid within the centrifuge chamber 32. As shown in Figures 5-7, the interface monitoring assembly may include a light source 50 and a photodetector 52 positioned and oriented to receive at least a portion of the light emitted by the light source 50. The illustrated light source 50 and photodetector 52 are associated with a fixed surface of the centrifuge compartment 34, but instead, either or both may be associated with a movable structure or component of the fluid processing apparatus 10, as in U.S. Patent No. 5,316,667 incorporated herein by reference.

[0036] The orientation of the various components of the interface monitoring system depends at least in part on the specific configuration of the centrifuge chamber 32, which is described in more detail herein. However, generally, the light source 50 emits a light beam "L" (e.g., a laser light beam) through the separated fluid components in the centrifuge chamber 32 (which may be formed from a material that substantially transmits light L or at least certain wavelengths of light L without absorbing them). A portion of the light L reaches the photodetector 52, which transmits a signal to the control unit 18 indicating the location of the interface between the separated fluid components. If the control unit 18 determines that the interface is in the wrong position (which may affect the separation efficiency of the centrifuge 16 and / or the quality of the separated blood components), it can issue a command to the appropriate component of the fluid processing apparatus 10 to correct its operation in order to move the interface to the correct position.

[0037] C. Other components of the fluid processing device In addition to the rotary membrane separator drive unit 14 and the centrifuge 16, the fluid processing apparatus 10 may include other components compactly arranged to assist in fluid processing.

[0038] A substantially horizontal portion 22 of the case 20 of the illustrated fluid processing apparatus 10 includes a cassette station 54 that houses a cassette 48 (Figure 4) of the fluid flow circuit 12. In one embodiment, the cassette station 54 is configured similarly to the cassette station of U.S. Patent No. 5,868,696 (incorporated herein by reference), but is adapted to include additional components and functions. The illustrated cassette station 54 includes a plurality of clamps or valves V1-V9 (Figure 1) that move between a plurality of positions (e.g., between a retracted or lowered position and an operating or raised position) to selectively contact or interact with the corresponding valve stations C1-C9 (Figures 2 and 4) of the cassette 48 of the fluid flow circuit 12. Depending on the configuration of the fluid flow circuit 12, its cassette 48 does not have to include valve stations C1-C9 for each of the valves V1-V9 of the cassette station 54, in which case fewer than all of the valves V1-V9 are used in the separation procedure.

[0039] In the operating position, valves V1-V9 engage with associated valve stations C1-C9 to prevent fluid flow through those valve stations C1-C9 (for example, by closing one or more ports associated with valve stations C1-C9, thereby obstructing fluid flow through those ports or more). In the retracted position, valves V1-V9 are disengaged from associated valve stations C1-C9 (or do not contact them as strongly as they do in the operating position) to allow fluid flow through those valve stations C1-C9 (for example, by opening one or more ports associated with valve stations C1-C9, thereby allowing fluid flow through those ports or more). Additional clamps or valves V10 and V11 are located outside the cassette station 54 and can interact with portions of the fluid flow circuit 12 or valve stations C10 and C11 (which may be the length of the pipe) to selectively allow and prevent fluid flow through them. The valves V1 to V9 of cassette station 54 and cassette 48, and the corresponding valve stations C1 to C9, can have different configurations and operations than valves V10 and V11 located away from cassette station 54, and valve stations C10 and C11.

[0040] The cassette station 54 may be equipped with additional components such as pressure sensors A1-A4, which interact with the sensor stations S1-S4 of the cassette 48 to monitor pressure at various locations in the fluid flow circuit 12. For example, if the fluid source is a human donor, one or more of the pressure sensors A1-A4 may be configured to monitor the pressure in the donor's vein during blood collection and return. Other pressure sensors A1-A4 may monitor the pressure in the rotating membrane separator 26 and the centrifuge chamber 32. The control unit 18 can receive signals from the pressure sensors A1-A4 indicating the pressure in the fluid flow circuit 12, and if the signals indicate a low or high pressure condition, the control unit 18 may initiate an alarm or error condition that warns the operator of the condition and / or attempts to bring the pressure to an acceptable level without operator intervention.

[0041] The fluid processing apparatus 10 also includes a plurality of pumps P1-P6 (which can be collectively referred to as the pump system) to allow fluid to flow through the fluid flow circuit 12. The pumps P1-P6 may be configured differently or similarly from one another and / or may function similarly or differently from one another. In the illustrated embodiment, the pumps P1-P6 are configured as peristaltic pumps, which can generally be configured as described in U.S. Patent No. 5,868,696. Each pump P1-P6 engages with different tube loops T1-T6 extending from the side of the cassette 48 (Figure 4) and is selectively operated under the command of the control unit 18 to allow fluid to flow through a portion of the fluid flow circuit 12, as will be described in detail later. In one embodiment, all or part of the cassette station 54 is capable of translational motion in and out of the case 20, enabling automatic loading of the tube loops T1-T6 to the associated pumps P1-P6.

[0042] The illustrated fluid processing apparatus 10 also includes an optical detection assembly or centrifuge sensor M1 for determining one or more properties of the fluid flowing out of and / or into the centrifuge 16. If the fluid flowing out of the centrifuge 16 contains red blood cells, the centrifuge sensor M1 may be configured to determine the hematocrit of the fluid. If the fluid flowing out of the centrifuge 16 is platelet-rich plasma, the centrifuge sensor M1 may be configured to determine the platelet concentration of the platelet-rich plasma. The centrifuge sensor M1 can detect one or more properties of the fluid by optically monitoring the fluid flowing through the tubes of the fluid flow circuit 12, or by any other suitable approach. The control unit 18 can receive signals from the centrifuge sensor M1 indicating the nature of the flow entering and leaving the centrifuge 16 (e.g., whether there is a flow of air or liquid through an inlet or outlet conduit connected to the centrifuge chamber 32, or whether a fluid is flowing or stagnating through such conduits), and the signals can be used to optimize the separation procedure. If one or more characteristics of the fluid flowing into or out of the centrifugal chamber 32 are outside the acceptable range, the control unit 18 may initiate an alarm or error condition to warn the operator of the condition. Exemplary optical detection assemblies are described in U.S. Patent No. 6,419,822 and U.S. Patent Application Publication No. 2019 / 0369008 (both incorporated herein by reference), but it should be understood that different approaches may be used to optically monitor the flow of fluid entering and leaving the centrifuge 16.

[0043] The illustrated fluid apparatus 10 further includes a rotating membrane outlet sensor M2, which houses a tube of a fluid flow circuit 12 that discharges the separated material from the rotating membrane separator 26. The rotating membrane outlet sensor M2 can monitor the material and determine one or more properties of the material by optically monitoring the material as it flows through the tube, or by any other suitable approach. In one embodiment, separated plasma flows through the tube, in which case the rotating membrane outlet sensor M2 may be configured to determine the amount of cellular blood components in the plasma and / or whether the plasma is hemolytic and / or hyperlipidemia. This can be done using an optical monitor of the type described in U.S. Patent No. 8,556,793 (incorporated herein by reference), or by any other suitable apparatus and / or method.

[0044] The illustrated fluid processing apparatus 10 also includes an air detector M3 (e.g., an ultrasonic bubble detector) that houses the tube of the fluid flow circuit 12 through which the fluid flows to the recipient. Since it may be advantageous to prevent air from reaching the recipient, the air detector M3 can transmit a signal to the control unit 18 indicating the presence or absence of air in the tube. If the signal indicates the presence of air in the tube, the control unit 18 can initiate an alarm or error condition to warn the operator of the condition and / or take corrective action to prevent air from reaching the recipient (e.g., by reversing the fluid flow through the tube or diverting the flow to an exhaust location).

[0045] The substantially vertical portion 24 of case 18 may include a plurality of weighers W1-W6 (six are shown, but more or fewer may be provided), each of which may support one or more fluid containers F1-F7 (Figure 2) of the fluid flow circuit 12. Containers F1-F7 receive fluid components or waste separated during processing, or classified non-biological fluids (e.g., priming fluid, intravenous infusion, or additive fluid). Each weigher W1-W6 sends a signal to the control unit 18 indicating the weight of the fluid in the associated containers F1-F7 to track the weight change in progress of the procedure. This allows the control unit 18 to process the incremental weight change to derive the fluid processing volume and flow rate, and subsequently generate a signal to control the processing event based at least partially on the resulting processing volume. For example, the control unit 18 can diagnose leaks and obstructions in the fluid flow circuit 12 and alert the operator.

[0046] The illustrated case 20 also includes a plurality of hooks or supports K1 and K2 that can support various components of the fluid flow circuit 12 or other objects of appropriate size and configuration.

[0047] D. Control Unit As described above, the fluid processing apparatus 10 includes a control unit 18 appropriately configured and / or programmed to control the operation of the fluid processing apparatus 10. In one embodiment, the control unit 18 includes a main processing unit (MPU) which may include, for example, an Intel Corporation Pentium® type microprocessor, but other types of conventional microprocessors may also be used. In one embodiment, the control unit 18 may be mounted inside a substantially vertical portion 24 of the case 20, adjacent to or integrated with an operator interface station (e.g., a touchscreen). In other embodiments, the control unit 18 and the operator interface station may be associated with a substantially horizontal portion 22, or integrated into a separate device connected to the fluid processing apparatus 10 (physically by cable or wirelessly).

[0048] The control unit 18 is configured and / or programmed to perform at least one fluid processing application, but more advantageously, it is configured and / or programmed to perform a variety of different fluid processing applications. For example, the control unit 18 may be configured and / or programmed to perform one or more of the following: double-unit erythrocyte collection procedures, plasma collection procedures, platelet-rich plasma / erythrocyte collection procedures, erythrocyte / platelet / plasma collection procedures, platelet collection procedures, platelet / plasma collection procedures, and mononuclear cell collection procedures. Additional or alternative procedural applications (e.g., plasma exchange, erythrocyte exchange, and photopheresis) may be included without departing from the scope of this disclosure.

[0049] More specifically, when performing any of these fluid processing applications, the control unit 18 is configured and / or programmed to control one or more of the following tasks: The fluid is drawn into a fluid flow circuit 12 attached to the fluid processing apparatus 10; the fluid is transported through the fluid flow circuit 12 to a location for separation (i.e., within the rotating membrane separator 26 or centrifugal separator 32 of the fluid flow circuit 12); the fluid is separated into two or more components as desired; and the separated components are transported to a storage container, a second location for further separation (e.g., either the rotating membrane separator 26 or centrifugal separator 32 not used in the initial separation stage), or a recipient (which may be the source from which the fluid was originally drawn).

[0050] This may include instructing the rotating membrane separator drive unit 14 and / or the centrifuge 16 to operate at a specific rotational speed, and instructing the pump to transport fluid through a portion of the fluid flow circuit 12 at a specific flow velocity. Thus, while specific components of the fluid processing apparatus 10 (e.g., the rotating membrane separator drive unit 14 or the centrifuge 16) are described as performing specific functions, it should be understood that these components are controlled by the control unit 18 to perform those functions.

[0051] Before, during, and after the procedure, the control unit 18 can receive signals from various components of the fluid processing device 10 to monitor various aspects of the operation of the fluid processing device 10 and the characteristics of the fluid and separated fluid components as they flow through the fluid flow circuit 12. If the operation of any component and / or one or more characteristics of the fluid or separated fluid components are outside acceptable limits, the control unit 18 can initiate an alarm or error condition to warn the operator and / or take action to correct the situation. Appropriate corrective actions will vary depending on the specific error condition and may include actions taken with or without operator involvement.

[0052] For example, the control unit 18 may include an interface control module that receives signals from the photodetector 52 and the centrifuge sensor M1 of the interface monitoring assembly. The signal received by the control unit 18 from the photodetector 52 indicates the position of the interface between separated fluid components in the centrifuge chamber 32, and the signal from the centrifuge sensor M1 indicates whether the target interface position should be adjusted. If the control unit 18 determines that the interface is in the wrong position, it can issue commands to the appropriate components of the fluid processing device 10 to change their operation to move the interface to the correct position. For example, the control unit 18 may instruct the pump system to allow fluid to flow into the centrifuge chamber 32 at different rates, and / or to remove the separated fluid components from the centrifuge chamber 32 at different rates, and / or to rotate the centrifuge chamber 32 by the centrifuge 16 at different rates.

[0053] If provided, an operator interface station associated with the control unit 18 allows the operator to view information about the system's operation (as alphanumeric characters and / or graphic images) on a screen or display unit. The operator interface station also allows the operator to select applications executed by the control unit 18, as well as to change certain functional and performance criteria of the system. If configured as a touchscreen, the screen of the operator interface station can receive input from the operator via touch activation. If the screen is not a touchscreen, the operator interface station can receive input from the operator via another input device, such as a computer mouse or keyboard. It is also within the scope of this disclosure that the operator interface station can receive input from both a touchscreen and a separate input device, such as a keypad.

[0054] II. Disposable Fluid Flow Circuits A. Overview The fluid flow circuit or flow set 12 (Figure 2) is intended to be a sterile, single-use, disposable item. Before commencing a given procedure, the operator loads the various components of the fluid flow circuit 12 into the case 20 in relation to the fluid processing device 10. The control unit 18 executes the procedure based on a pre-configured protocol, taking into account other inputs from the operator. Upon completion of the procedure, the operator disconnects the fluid flow circuit 12 from its association with the fluid processing device 10. The portion of the fluid flow circuit 12 that holds the collected fluid components (e.g., collection container or bag) is removed from the case 20 and held for storage, immediate use, or further processing. The remaining portion of the fluid flow circuit 12 is removed from the case 20 and discarded.

[0055] Depending on the procedure performed using the system, various different disposable fluid flow circuits can be used in combination with the fluid processing apparatus 10, using appropriate fluid flow circuits. However, generally speaking, the fluid flow circuit 12 includes a cassette 48 (Figure 4), and the other components of the fluid flow circuit 12 are connected by flexible tubes or conduits. The other components include a plurality of fluid containers F1-F7 (e.g., for holding the fluid to be processed, separated fluid components, priming fluid, or additive solutions), one or more fluid source access devices (e.g., connectors for accessing the fluid in the fluid containers), a centrifugal chamber 32 (Figures 8-10), and (optionally) a rotating membrane separator 26.

[0056] Figure 2 shows an exemplary fluid flow circuit 12 having a single fluid access device (e.g., a bloodletting needle) alternately for drawing fluid into the fluid flow circuit 12 and for carrying fluid out of the fluid flow circuit 12. The illustrated fluid flow circuit 12 is for illustrative purposes only, and it should be understood that the principles described herein can be used in fluid flow circuits of different configurations. This may include a fluid flow circuit having a pair of fluid access devices, one dedicated to drawing fluid into the fluid flow circuit and the other dedicated to carrying fluid out of the fluid flow circuit.

[0057] B. Cassette and tube Cassette 48 (Figure 4) provides a centralized, programmable, integrated platform for all the pumping and numerous valve functions required for a given fluid handling procedure. In one embodiment, Cassette 48 is configured similarly to the Cassette of U.S. Patent No. 5,868,696, but is adapted to include additional components (e.g., more pipe loops T1-T6) and functions.

[0058] During use, the cassette 48 is attached to the cassette station 54 of the fluid processing apparatus 10, and positioned so that the flexible diaphragm of the cassette 48 is in contact with the cassette station 54. The flexible diaphragm covers a series of internal cavities formed by the body of the cassette 48. Different internal cavities define sensor stations S1-S4, valve stations C1-C9, and multiple flow paths or conduits L1-L23 (Figure 2). The side of the cassette 48 opposite to the flexible diaphragm is sealed by another flexible diaphragm or rigid cover, thereby sealing the fluid flow through the cassette 48 from the external environment.

[0059] Each sensor station S1-S4 is aligned with its associated pressure sensors A1-A4 in the cassette station 54, and each pressure sensor A1-A4 can monitor the pressure within its associated sensor station S1-S4. Each valve station C1-C9 is aligned with its associated valves V1-V9, and can define one or more ports that allow fluid communication between the valve stations C1-C9 and another internal cavity (e.g., a flow path) in the cassette 48. As described above, each valve V1-V9 is movable under command of the control unit 18 and can move between multiple positions (e.g., between a retracted or lowered position and an activated or raised position) to selectively contact the valve stations C1-C9 in the cassette 48. In the activated position, the valves V1-V9 engage with their associated valve stations C1-C9 to close one or more of their ports, preventing fluid flow therethrough. In the retracted position, valves V1-V9 detach from their associated valve stations C1-C9 (or contact them with less force than when in the operating position), opening one or more ports associated with valve stations C1-C9, thereby allowing fluid flow.

[0060] As described, multiple tube loops T1-T6 extend from the side of the cassette 48 and interact with the pumps P1-P6 of the fluid processing device 10. In the illustrated embodiment, six tube loops T1-T6 extend from the cassette 48 and are received by one of the six pumps P1-P6, but in other embodiments, the procedure may not require the use of all of the pumps P1-P6. In this case, the cassette 48 may contain fewer than six tube loops. Different pumps P1-P6 can interact with the tube loops T1-T6 of the cassette 48 to perform different tasks during the isolation procedure. It should be understood that the cassettes of different fluid flow circuits 12 can have different configurations (e.g., fewer sensor stations, valve stations, and / or tube loops, without departing from the scope of this disclosure).

[0061] Additional tubes or conduits extend from the sides of the cassette 48 and connect to other components of the fluid flow circuit 12, such as various fluid containers F1-F7, a rotating membrane separator 26, and a centrifugal chamber 32. The number and contents of the various fluid containers F1-F7 depend on the procedure in which the fluid flow circuit 12 is used. Tubes connected to the centrifugal chamber 32 (including one inlet conduit and two outlet conduits) may be engaged by a yoke member 44 of the centrifuge 16 and circulate the umbilix 46, and may be assembled into the umbilix 46 (Figure 3) to spin or rotate the centrifugal chamber 32 during the separation procedure (as described above).

[0062] Various additional components may be incorporated into the tubes exiting the cassette 48 or into one of the cavities of the cassette 48. For example, as shown in Figure 2, a manual clamp 51 may be associated with one or more lines leading to a fluid source and / or fluid recipient, a return line filter 53 (e.g., a micro-aggregation filter) may be associated with a line leading to a fluid recipient, filters may be placed upstream of one or more fluid containers to remove substances (e.g., white blood cells) from separated components (e.g., red blood cells) flowing into the fluid container, and / or an air trap 55 may be placed upstream of the centrifugal chamber 32.

[0063] C. Centrifuge vent An exemplary centrifugal chamber 32 is shown in Figure 8. Figures 9 and 9A show conventionally configured fluid channels or separation channels that can be defined by the centrifugal chamber 32. Figure 10 shows an exemplary fluid channel or separation channel according to one aspect of the present disclosure that can be defined by the centrifugal chamber 32, and Figure 10A compares the channel in Figure 10 with a conventional channel. The differences between the separation channel in Figure 10 and a conventional channel are described in more detail herein.

[0064] In the illustrated embodiment, the body of the centrifuge chamber 32 is preformed from a rigid, biocompatible plastic material such as non-plasticized medical-grade acrylonitrile-butadiene-styrene (ABS) to the desired shape and configuration (e.g., by injection molding). All contours, ports, channels, and walls that affect the fluid separation process are preformed in a single injection molding operation. Alternatively, the centrifuge chamber 32 can be formed by separate molded parts, either as a nested cup-shaped subassembly or as two symmetrical halves.

[0065] The central hub 56 of the centrifugal chamber 32 (Figure 8) coincides with the rotation axis 38 when the chamber 32 is installed within the centrifugal compartment 34. The central hub 56 includes a molded receptacle suitable for receiving the end of the umbilics 46 of the fluid flow circuit 12 (Figure 3). A suitable receptacle and a method by which the umbilics 46 cooperates with the receptacle to deliver fluid to and remove fluid from the centrifugal chamber 32 are described in detail in U.S. Patent No. 8,075,468.

[0066] The illustrated centrifugal separation chamber 32 has radially spaced inner (low-G) walls 58 and outer (high-G) walls 60 extending around a central hub 56. The low-G walls 58 and high-G walls 60 extend from a lower end wall 62 and an open upper end 63. The terms “upper” and “bottom” are not intended to restrict the structure or orientation of the centrifugal separation chamber 32 (for example, Figure 9 shows the lower end 62 positioned above the upper end 63), but rather are used to describe various aspects of the centrifugal separation chamber 32. The cover 64 is associated with the open upper end 63 of the centrifugal separation chamber 32 and has a simple flat portion that can be easily welded or otherwise secured to the body of the centrifugal separation chamber 32. Since all functions affecting the separation process are incorporated into a single injection-molded component, tolerance differences between the cover 64 and the body of the centrifugal separation chamber 32 do not affect the separation efficiency of the centrifugal separation chamber 32. The low G wall 58 and high G wall 60, the bottom 62, and the cover 64 together define an enclosed, substantially annular channel 66. As described above, exemplary separation channels are shown in Figures 9-10A and will be described in more detail herein.

[0067] To enable injection molding of the centrifugal separation chamber 32, a 1° inward taper can be incorporated into the high-G wall 60 (towards the central axis of the chamber 32, from the open upper end 63 to the lower end 62). Conversely, a 1° outward taper can be incorporated into the low-G wall 58 (away from the central axis of the chamber 32, from the upper end 63 to the lower end 62). Thus, the width of the separation channel 66 (i.e., the distance between the low-G wall 58 and the high-G wall 60) tends to vary along the height of the separation channel 66. As will be described in more detail, the width of the separation channel 66 around the axis (i.e., from the upstream end 67 to the downstream end 69 of the channel 66) can vary, so references to the width of the separation channel 66 around the axis should be understood to refer to the width of the channel 66 at a particular axial position or height.

[0068] Multiple radial walls extend from the central hub 56 to the separation channel 66, with an inlet passage 68 defined between two radial walls 70, 72, thereby allowing fluid to flow from the umbilics 46 to the channel 66 in a single flow configuration. One radial wall 70 (sometimes referred to as the “terminus wall”) is coupled to the high-G wall 60, separating the upstream end 67 of the channel 66 from the downstream end 69. As used herein, the terms “upstream end” and “downstream end,” when used in relation to the region of the separation channel 66, may refer to the first quarter or quadrant of the channel 66 (i.e., the region encompassing approximately 90° of the channel 66 on the side of the terminal wall 70 where the fluid enters the channel 66) and the last quarter or quadrant of the channel 66 (i.e., the region enclosing approximately 90° of the channel 66 on the side of the terminal wall 70 opposite the upstream end 67 of the channel 66), respectively. These terms are most frequently used herein to refer to the locations of various components or formations related to the isolation channel 66 (for example, the inlet passage 68 opens into the channel 66 at the upstream end 67 of the channel 66). In certain embodiments (depending on the configuration of the components described as being present at the upstream end 67 or downstream end 69 of the isolation channel 66), the terms may refer to smaller areas of the isolation channel 66. For example, the term “upstream end” may refer only to the first 45° or 30° or less of the channel 66, and the term “downstream end” may refer only to the last 45° or 30° or less of the channel 66.

[0069] The illustrated centrifugal separation chamber 32 further includes a first outlet passage 74 and a second outlet passage 76, respectively, which may be defined by opposing surfaces of radially extending inner walls. Both the first and second outlet passages 74 and 76 extend between the central hub 56 and the separation channel 66. In the illustrated embodiment, the first (low-G) outlet passage 74 extends radially inward from an opening located in the low-G wall 58, and the second (high-G) outlet passage 76 extends radially inward from an opening associated with the high-G wall 60. The illustrated low-G outlet passage 74 may be located adjacent to the inlet passage 68 (at the upstream end 67 of the separation channel 66), and the high-G outlet passage 76 may be located at the downstream end 69 on the opposite side of the channel 66.

[0070] Further characteristics of exemplary separation channels are described in more detail herein.

[0071] III. Principles of Centrifugal Separation and Interface Detection As the fluid flowing into the separation channel 66 rotates the centrifuge chamber 32 around the rotation axis 38, it separates into an optically dense layer "R" and an optically less dense layer "P" (Figures 11-13). The optically dense layer R is formed when larger and / or heavier fluid particles move toward the high-G wall 60 under the influence of centrifugal force. If the fluid being separated is blood, the optically dense layer R typically contains red blood cells, but depending on the speed at which the centrifuge chamber 32 rotates, other cellular components (e.g., larger white blood cells) may also be present in the optically dense layer R.

[0072] If the fluid being separated is blood, the layer P with low optical density typically contains plasma components such as platelet-rich plasma. Depending on the speed at which the centrifuge chamber 32 rotates and the length of time the blood is present in it, other components (e.g., smaller leukocytes) may also be present in the optically low-density layer P.

[0073] In one embodiment, the fluid introduced into the separation channel 66 via the inlet passage 68 moves in a substantially clockwise direction (direction in Figure 8) as the optically denser layer R separates from the optically less dense layer P. The optically denser layer R continues to move clockwise along the length of the separation channel 66 from the upstream end 67 to the downstream end 69, along the high G wall 60, where it exits the channel 66 via the high G outlet passage 76. The optically less dense layer P, separated from the optically denser layer R, reverses direction and moves counterclockwise along the low G wall 58 to the low G outlet passage 74 adjacent to the inlet passage 68.

[0074] The transition between an optically dense layer R and an optically less dense layer P can be called the interface "N". If the fluid being separated is blood, the buffy coat containing mononuclear cells and peripheral blood stem cells may be located at interface N. As shown in Figures 11-13, the position of interface N within the separation channel 66 of the centrifuge chamber 32 can shift dynamically during fluid processing. If the position of interface N is too high (i.e., too close to the low-G wall 58 and low-G outlet passage 74, as shown in Figure 12), red blood cells may flow into the low-G outlet passage 74, potentially negatively impacting the quality of the low-density component (platelet-rich plasma). On the other hand, if the position of interface N is too low (i.e., too far from the low-G wall 58, as shown in Figure 13), the collection efficiency of the system may be impaired. The ideal or target interface position can be determined experimentally, and this may vary depending on any of several factors (e.g., the configuration of the centrifuge chamber 32, the speed at which the centrifuge chamber 32 rotates around the rotation axis 38, etc.).

[0075] As described above, the fluid processing apparatus 10 may include an interface monitoring assembly (including a light source 50 and a photodetector 52), a centrifuge sensor M1, and a control unit 18 having an interface control module for monitoring and, if necessary, adjusting or correcting the position of the interface N. In the illustrated embodiment, the centrifugal chamber 32 is formed by an inclined section 78 extending from the high-G wall 60 at an angle α across at least a portion of the separation channel 66 (Figures 8 and 11-13). The angle α measured with respect to the rotation axis 38 is approximately 25° in one embodiment. Figures 11-13 show the orientation of the inclined section 78 as viewed from the low-G wall 58 of the centrifugal chamber 32. Although a flexible separation chamber is described, the general structure and function of the inclined section 78 can be better understood by referring to U.S. Patent No. 5,632,893. The inclined portion 78 can be located at any of a number of positions between the upstream end 67 and the downstream end 69 of the separation channel 66, but in one embodiment, the inclined portion 78 can be located substantially adjacent to the low-G outlet passage 74 in the path of the fluid and / or fluid components moving from the inlet passage 68 to the low-G outlet passage 74.

[0076] The inclined portion 78 makes the interface N between the optically dense layer R and the optically less dense layer P more distinguishable for detection, and displays the optically dense layer R, the optically less dense layer P, and the interface N for observation through the light-transmitting portion of the centrifugal separation chamber 32. For this purpose, the inclined portion 78 and at least the portion of the centrifugal separation chamber 32 that is angled with the inclined portion 78 can be formed from a light-transmitting material, but it may be advantageous to form the entire centrifugal separation chamber 32 from the same light-transmitting material.

[0077] As shown in Figures 5-7, in the illustrated embodiment, the light source 50 of the interface monitoring system is associated with a fixture or wall of the centrifuge compartment 34 and oriented to emit light L directed toward the rotation axis 38 of the centrifuge 16. If the photodetector 52 is positioned at a certain angle to the light source 50 (as in the illustrated embodiment), the light L emitted by the light source 50 must be redirected from its initial path before reaching the photodetector 52. In the illustrated embodiment, the light L is redirected by a reflector associated with a light-transmitting portion of the inner wall portion 58, as shown in Figures 5 and 6. The reflector may be a separate component fixed to the low-G wall 58 (e.g., by being bonded thereto) or it may be integrally formed with the body of the centrifuge chamber 32.

[0078] In one embodiment, the reflector may be a reflective surface such as a mirror, oriented (for example, at an angle of 45°) to direct the light L emitted by the light source 50 towards the photodetector 52. In another embodiment, the reflector is provided as a prism reflector 80 (Figures 7, 14, and 15) formed of a light-transmitting material (for example, a transparent plastic material) and having an inner wall 82 and an outer wall 84 and a first end wall 86 and a second end wall 88 (Figure 14). The inner wall 82 is positioned relative to the low-G wall 58 of the centrifugal separation chamber 32 and is oriented substantially perpendicular to the initial path of the light L from the light source 50. This allows the light L from the light source 50 to enter the prism reflector 80 through the inner wall 82 while traveling along its initial path. The light L continues to pass through the prism reflector 80 along its initial path until it encounters the first end wall 86. The first end wall 86 is oriented at an angle (for example, about 45°) with respect to the inner wall 82 and the second end wall 88, so that the light L is redirected within the prism reflector 80 rather than exiting the prism reflector 80 through the first end wall 86.

[0079] The first end wall 86 directs the light L toward the second end wall 88 (Figure 15) at an angle to its original path (this angle may be approximately 90°, from a path toward the axis of rotation 38 to a path substantially parallel to the axis of rotation 38). The first end wall 86, inner wall 82, and outer wall 84 of the prism reflector 80 can be configured to transmit the redirected light L from the first end wall 86 to the second end wall 88 by total internal reflection. The second end wall 88 is oriented substantially perpendicular to the redirected path of the light L passing through the prism reflector 80 so that the light L exits the prism reflector 80 through the second end wall 88 and continues along its redirected path. In one embodiment, the second end wall 88 is roughened, textured, or otherwise treated or adjusted to diffuse the light L as it exits the prism reflector 80, thereby making it more certain that the light L reaches the photodetector 52 (Figure 7).

[0080] The prism reflector 80 may be angularly aligned with the inclined portion 78 so that when the inclined portion 78 is rotated within the path of the light L, the light L from the light source 50 enters only the prism reflector 80. Otherwise (when the inclined portion 78 is not in the path of the light L), the light L does not reach the prism reflector 80 and therefore does not reach the photodetector 52.

[0081] As the inclined section 78 first rotates into the path of light L from the light source 50, the light L begins to reach the prism reflector 80, which directs the light L towards the photodetector 52. This increases the voltage output of the photodetector 52 (i.e., the signal transmitted from the photodetector 52 to the control unit 18) to a non-zero value or state. The inclined section 78 and the prism reflector 80 rotate and eventually move out of alignment with the light source 50, at which point the light L no longer reaches the prism reflector 80, and the voltage output of the photodetector 52 returns to a low or zero state.

[0082] While the inclined section 78 and the prism reflector 80 rotate along the path of light L from the light source 50, the light L continues through the separation channel 66 and the fluid within the channel 66. At least a portion of the light L (i.e., the portion not absorbed or reflected by the fluid) exits the separation channel 66 by colliding with and entering the light-transmitting portion of the low-G wall 58. The light L passes through the low-G wall 58 and enters the prism reflector 80. The prism reflector 80 redirects the light L from its original path towards the photodetector 52, as described above.

[0083] The photodetector 52 generates a signal that is transmitted to an interface control module of the control unit 18, which can determine the position of the interface N on the inclined portion 78. In one embodiment, the position of the interface N is associated with a change in the amount of light L transmitted through the optically low-density layer P and the optically high-density layer R. For example, the light source 50 may be configured to emit light L that is more easily transmitted by platelet-rich plasma than by red blood cells, such as red visible light that is substantially absorbed by red blood cells (from a laser or a light source L of a different configuration). The optically low-density layer P and the optically high-density layer R each occupy a specific portion of the inclined portion 78, and the photodetector 52 receives different amounts of light L depending on whether the light L passes through the optically low-density layer P or the optically high-density layer R on the inclined portion 78. The percentage of the inclined portion 78 occupied by each layer is related to the position of the interface N in the channel 66. Therefore, by measuring a relatively high time duration for which the voltage output or signal from the photodetector 52 is present (corresponding to the time for which light L passes only through the low optical density layer P on the inclined section 78), the control unit 18 can determine the position of interface N and, if necessary, take measures to correct the position of interface N. An exemplary approach for adjusting the position of interface N is described in detail in the PCT patent application, International Publication No. WO2018 / 053217A1.

[0084] IV. Isolation Channel Configuration Now, let's return to the configuration of the separation channel 66 defined by the centrifuge chamber 32. Figures 9 and 9A show a conventional separation channel 66a that can be defined by the centrifuge chamber 32. For illustrative purposes, please note that the orientation of the separation channel 66a shown in Figure 9 is the opposite of the orientation of the centrifuge chamber 32 shown in Figure 8 (i.e., the bottom end 62 is shown at the top of Figure 9).

[0085] Although various surfaces and structures of the centrifugation chamber are not visible in Figures 9–10A, it should be clear that the illustrated separation channels are fully defined by the corresponding chamber structures and surfaces described herein and shown in Figure 8. Therefore, for simplicity and brevity, when describing the separation channels in Figures 9–10A, the centrifugation chamber itself and the various surfaces and configurations of the chamber can be briefly referred to (for example, by stating that the chamber in Figures 9–10A has a particularly configured inclined section rather than stating that the chamber defining the illustrated channel has a particularly configured inclined section). Similarly, Figures 9–10A may have annotations (with dashed leader lines) representing the chamber surfaces that define specific features of the illustrated separation channels, rather than using new reference numbers for channel features arising from the chamber surfaces (for example, identifying channel features defined as inclined sections by the inclined sections of the chamber, rather than using unique identifiers for that region of the channel itself).

[0086] As described above, the inlet passage 68 and the low-G outlet passage 74 open into the separation channel 66a at the upstream end 67 of channel 66a, and the inclined section 78 extends across a portion of the upstream end 67 of channel 66a. The high-G outlet passage 76 opens into the separation channel 66a at the downstream end 69 of channel 66a. All of the radial walls extending between the central hub 56 and the separation channel 66a and defining the inlet passage 68 and the outlet passages 74 and 76 are defined at the open upper end 63 of the centrifugal separation chamber 32 (shown at the bottom of Figure 9), but the inlet passage 68 is configured to open into channel 66a at its lower end 62, while the outlet passages 74 and 76 are configured to open into channel 66a at its upper end 63. This configuration is advantageous in that it increases the distance that the separated fluid components must travel through the separation channel 66a before exiting through either of the outlet passages 74 or 76, thereby improving the purity of the separated fluid components.

[0087] The low-G wall 58 has a larger radius at the downstream end 69 of the separation channel 66a than at the upstream end 67 (at each axial position as described above). Figure 9A shows the radius of the low-G wall 58 gradually increasing from the upstream end 67 (just downstream of the inclined section 78) of the separation channel 66a to the downstream end 69 of the channel 66a, which may include the low-G wall 58 configured as a uniform helix downstream of the inclined section 78. This configuration of the low-G wall 58 may be advantageous when separating blood into concentrated red blood cells (exiting the separation channel 66a via the high-G exit passage 76) and platelet-rich plasma (exiting the channel 66a via the low-G exit passage 74). This is because the plasma that continues to be released from the red blood cells downstream of the inlet passage 68 flows in the direction in which the plasma thickness increases (i.e., back upstream toward the low-G exit passage 74). The reflux of plasma helps to draw platelets that were not captured by the initial elutriation separation process toward the upstream end 67 of the separation channel 66a. There, the platelets can be captured by the high-velocity plasma flow present near the low-G exit passage 74 and drawn out of channel 66a.

[0088] The high-G wall 60 has a uniform radius from the upstream end 67 to the downstream end 69 of the separation channel 66a (at each axial position). The separation channel 66a is shown with a recessed passage 90 within the high-G wall 60 at the downstream end 69 of the channel 66a, which may be advantageous in preventing any of the fluid components separated at the low-G wall 58 (e.g., platelet-rich plasma) from entering the high-G outlet passage 76.

[0089] The radius of the low-G wall 58 increases from the upstream end 67 to the downstream end 69 of the separation channel 66a, while the radius of the high-G wall 60 remains uniform, and the width of the channel 66a (at each axial position) decreases from the upstream end 67 to the downstream end 69, as best shown in Figure 9A. The downstream end 69 of the separation channel 66a may be so thin that it makes the manufacturing of the centrifugal separation chamber 32 difficult. For example, the core of the required mold tool may be so thin that it is prone to premature failure due to the high stresses repeated during the molding process. One approach to reduce the risk of mold tool core failure is to increase the uniform radius of the high-G wall 60 to widen the separation channel 66a at all positions. This would allow for a thicker, stronger core. However, such an approach may be disadvantageous in that it significantly increases the volume of the separation channel 66a (e.g., from 51.4 mL to 73.2 mL), which may be problematic when platelets are collected from blood (the extracorporeal volume is preferably kept to a minimum or at least reduced for the platelet collection procedure).

[0090] Therefore, it was found that it is preferable to increase the radius of only a portion of the high G wall 60, or to increase the radius of the high G wall 60 to different degrees at different locations along the length of the separation channel 66, rather than uniformly increasing the radius of the high G wall 60. Figure 10 shows one possible configuration of a separation channel 66b defined by a high G wall 60a having a non-uniform radius, according to one aspect of the present disclosure. Figure 10A shows different configurations of the separation channels 66a and 66b and the high G walls 60 and 60a.

[0091] As described above, the conventional separation channel 66a is thinnest at its downstream end 69. Therefore, to increase the width of the separation channel at its downstream end 69 (assuming no changes are made to the configuration of the low-G wall 58) and to allow for a thicker mold tool core, the high-G wall 60a shown in Figures 10 and 10A has a larger radius at the downstream end 69 of the separation channel 60b than at the upstream end 67 (at each axial position). Figures 10 and 10A show a configuration in which the high-G wall 60a includes a tapered portion 92 that extends along a portion of the length of the separation channel 66b (including the downstream end 69 of the channel 66b). The radius of the high-G wall 60a gradually increases from the upstream portion 94 of the tapered portion 92 to the downstream portion 96 of the tapered portion 92 (coinciding with the downstream end 69 of the separation channel 66b) (at each axial position). This may include a tapered portion 92 configured as a uniform helix.

[0092] In exemplary embodiments, the tapered portion 92 is configured as a uniform helix with a pitch of 0.307 cm, thereby increasing the radius of the high-G wall 60a at the downstream end 69 of the separation channel 66b by approximately 1.5 mm (compared to the radius of the conventional high-G wall 60 at the downstream end 69 of the channel 66a). However, the starting position of the tapered portion 92, the rate at which the radius of the high-G wall 60b increases along the tapered portion 92, and the extent to which the radius of the high-G wall 60a at the downstream end 69 of the separation channel 66b is greater than the radius of the high-G wall 60a at the upstream position 94 of the tapered portion 92 can vary without departing from the scope of the disclosure. For example, in the illustrated embodiment, the tapered portion 92 extends along a substantially semicircular portion of the separation channel 66b (i.e., along the rear portion of the channel 66b), and the high-G wall 60a upstream of the tapered portion 92 has a uniform radius (at each axial position). If the low-G wall 58 is provided according to a conventional design (having a radius that gradually increases from the upstream end 67 to the downstream end 69 of the separation channel 66b), the width of the channel 66b decreases (at each axial position) from the upstream end 67 of the channel 66b to the end of the portion of the high-G wall 60a that has a uniform radius. With respect to the portion of the separation channel 66b that extends along the tapered portion 92 of the high-G wall 60a, it can have a substantially uniform width (when the curvature of the tapered portion 92 matches the curvature of the low-G wall 58) or a non-uniform width at each axial position (when the curvature of the tapered portion 92 differs from the curvature of the low-G wall 58).

[0093] According to an alternative embodiment, the tapered portion 92 of the high-G wall 60a can extend from the upstream end 67 to the downstream end 69 of the separation channel 66b, in which case the radius of the high-G wall 60a gradually increases from the upstream end 67 to the downstream end 69 of the channel 66b (just upstream of the recessed passage 90 within the high-G wall 60a in the high-G outlet passage 76). This may include a tapered portion 92 (i.e., the entire high-G wall 60a) that is configured as a uniform helix upstream of the recessed passage 90 within the high-G wall 60a at the downstream end 69 of the separation channel 66b. In such an embodiment, if the curvature of the high-G wall 60a matches the curvature of the low-G wall 58, the separation channel 66b may have a substantially uniform width at each axial position from the upstream end 67 (just downstream of the inclined portion 78) to the downstream end 69 (just upstream of the recessed passage 90 within the high-G wall 60a). On the other hand, if the curvature of the high-G wall 60a differs from that of the low-G wall 58, the separation channel 66b will instead have a non-uniform width from the upstream end 67 to the downstream end 69 (at each position in the axial direction).

[0094] manner Embodiment 1. A fluid separation chamber for rotation around an axis, comprising a central hub coinciding with the axis, a substantially annular low-G wall and a substantially annular high-G wall extending around the central hub at a distance from each other to define a separation channel having an upstream end and a downstream end between them, a plurality of radial walls extending from the central hub to the separation channel to define a terminal wall separating the upstream end of the separation channel from the downstream end of the channel, an inlet passage at the upstream end of the separation channel, a low-G outlet passage and a high-G outlet passage, wherein the high-G wall has a larger radius at the downstream end of the separation channel than at the upstream end of the separation channel at each axial position.

[0095] Embodiment 2. The fluid separation chamber according to Embodiment 1, wherein the high-G wall includes a tapered portion, and the tapered portion has a radius that gradually increases from the upstream portion to the downstream portion of the tapered portion at each axial position.

[0096] Embodiment 3. The fluid separation chamber according to Embodiment 2, wherein the tapered portion of the high-G wall has a radius configured as a uniform helix.

[0097] Embodiment 4. The fluid separation chamber according to Embodiment 2 or Embodiment 3, wherein the high-G wall has a uniform radius at each axial position upstream of the tapered portion.

[0098] Embodiment 5. The fluid separation chamber according to Embodiment 4, wherein the tapered portion extends along the substantially semicircular portion of the separation channel.

[0099] Embodiment 6. A fluid separation chamber according to Embodiment 2 or Embodiment 3, wherein the tapered portion extends from the upstream end of the separation channel to the downstream end of the separation channel.

[0100] Embodiment 7. A fluid separation chamber according to any one of Embodiments 1 to 6, wherein the low-G wall has a larger radius at the downstream end of the separation channel than at the upstream end of the separation channel at each axial position.

[0101] Embodiment 8. A fluid separation chamber according to any one of Embodiments 1 to 7, wherein the low-G wall has a radius that gradually increases from the upstream end of the separation channel toward the downstream end of the separation channel at each axial position.

[0102] Embodiment 9. A fluid separation chamber according to any one of Embodiments 1 to 8, wherein the low-G wall has a radius configured as a uniform helix from the upstream end to the downstream end of the separation channel.

[0103] Embodiment 10. The fluid separation chamber according to Embodiment 1, wherein the high-G wall includes a tapered portion, the tapered portion has a radius that gradually increases from the upstream portion to the downstream portion of the tapered portion at each axial position, the high-G wall has a uniform radius upstream of the tapered portion at each axial position, the low-G wall has a radius that gradually increases from the upstream end to the downstream end of the separation channel at each axial position, and the separation channel has a non-uniform width upstream of the tapered portion at each axial position.

[0104] Embodiment 11. The fluid separation chamber according to Embodiment 10, wherein the separation channel has a substantially uniform width along the tapered portion at each axial position.

[0105] Embodiment 12. The fluid separation chamber according to Embodiment 10, wherein the separation channel has a non-uniform width along the tapered portion at each axial position.

[0106] Embodiment 13. A fluid separation chamber according to any one of Embodiments 10 to 12, wherein the tapered portion and the low-G wall each have a radius configured as a uniform helix.

[0107] Embodiment 14. The fluid separation chamber according to Embodiment 1, wherein each of the low-G wall and the high-G wall has a radius configured as a uniform helix from the upstream end to the downstream end of the separation channel.

[0108] Embodiment 15. The fluid separation chamber according to Embodiment 14, wherein the separation channel has a substantially uniform width from the upstream end to the downstream end of the separation channel at each axial position.

[0109] Embodiment 16. The fluid separation chamber according to Embodiment 14, wherein the separation channel has a non-uniform width from the upstream end to the downstream end of the separation channel at each axial position.

[0110] Embodiment 17. A fluid separation chamber according to any one of Embodiments 1 to 16, wherein the low-G outlet passage is open into the separation channel at the upstream end of the separation channel.

[0111] Embodiment 18. A fluid separation chamber according to any one of Embodiments 1 to 17, wherein the high-G outlet passage is open into the separation channel at the downstream end of the separation channel.

[0112] Embodiment 19. A fluid separation chamber according to any one of Embodiments 1 to 18, wherein the low-G outlet passage and the high-G outlet passage are open into the separation channel at the upper end of the separation channel.

[0113] Embodiment 20. A fluid separation chamber according to any one of Embodiments 1 to 19, wherein the inlet passage is open into the separation channel at the lower end of the separation channel.

[0114] It will be understood that the embodiments and examples described above illustrate some applications of the principles of the subject matter. Numerous modifications can be made by those skilled in the art without departing from the spirit and scope of the claimed subject matter, including combinations of features individually disclosed or claimed herein. For these reasons, the scope of this specification is not limited to the above description but is as set forth in the following claims, and the claims may cover the features of this specification, including combinations of features individually disclosed or claimed herein.

Claims

1. a fluid separation chamber for rotation about an axis, a central hub coincident with said axis; a generally annular low-G wall and a generally annular high-G wall extending in spaced relation around the central hub to define a separation channel having an upstream end and a downstream end therebetween; a plurality of radial walls extending from the central hub into the separation channel to define an end wall separating the upstream end of the separation channel from the downstream end of the channel; an inlet passage at the upstream end of the separation channel; a low-G outlet passage; and a high-G outlet passage; A fluid separation chamber, wherein the high-G wall has a larger radius at each axial position at the downstream end of the separation channel than at the upstream end of the separation channel.

2. 2. The fluid separation chamber of claim 1, wherein the high-G wall includes a tapered portion, the tapered portion having a radius that increases at each axial position from an upstream portion of the tapered portion to a downstream portion of the tapered portion.

3. The fluid separation chamber of claim 2 , wherein the tapered portion of the high-G wall has a radius configured as a uniform spiral.

4. 4. A fluid separation chamber according to claim 2 or claim 3, wherein the high-G wall has a uniform radius at each axial position upstream of the tapered section.

5. The fluid separation chamber of claim 4 , wherein the tapered portion extends along a generally semicircular portion of the separation channel.

6. 4. The fluid separation chamber of claim 2 or claim 3, wherein the tapered portion extends from the upstream end of the separation channel to the downstream end of the separation channel.

7. 4. The fluid separation chamber of claim 1, wherein the low-G wall has a larger radius at each axial position at the downstream end of the separation channel than at the upstream end of the separation channel.

8. 4. The fluid separation chamber of claim 1, wherein the low-G wall has a radius that gradually increases from the upstream end of the separation channel toward the downstream end of the separation channel at each axial position.

9. 4. The fluid separation chamber of claim 1, wherein the low-G wall has a radius configured as a uniform spiral from the upstream end of the separation channel to the downstream end of the separation channel.

10. the high-G wall includes a tapered portion, the tapered portion having a radius that increases at each axial position from an upstream portion of the tapered portion to a downstream portion of the tapered portion; the high-G wall has a uniform radius upstream of the tapered section at each axial location; the low-G wall has a radius that gradually increases at each axial position from the upstream end of the separation channel to the downstream end of the separation channel; 2. The fluid separation chamber of claim 1, wherein the separation channel has a non-uniform width upstream of the tapered portion at each axial position.

11. The fluid separation chamber of claim 10 , wherein the separation channel has a substantially uniform width along the tapered portion at each axial position.

12. The fluid separation chamber of claim 10 , wherein the separation channel has a non-uniform width at each axial position along the tapered portion.

13. 13. A fluid separation chamber according to any one of claims 10 to 12, wherein the tapered portion and the low-G wall each have a radius configured as a uniform spiral.

14. The fluid separation chamber of claim 1 , wherein the low-G wall and the high-G wall each have a radius configured as a uniform spiral from the upstream end of the separation channel to the downstream end of the separation channel.

15. 15. The fluid separation chamber of claim 14, wherein the separation channel has a substantially uniform width at each axial position from the upstream end of the separation channel to the downstream end of the separation channel.

16. 15. The fluid separation chamber of claim 14, wherein the separation channel has a non-uniform width at each axial position from the upstream end of the separation channel to the downstream end of the separation channel.

17. 4. A fluid separation chamber according to claim 1, wherein the low-G outlet passage opens into the separation channel at the upstream end of the separation channel.

18. 4. A fluid separation chamber according to claim 1, wherein the high-G outlet passage opens into the separation channel at the downstream end of the separation channel.

19. 4. A fluid separation chamber according to claim 1, wherein the low-G outlet passage and the high-G outlet passage open into the separation channel at an upper end of the separation channel.

20. 4. A fluid separation chamber according to any one of claims 1 to 3, wherein the inlet passage opens into the separation channel at the lower end thereof.

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