Liquid pumping cassette and associated pressure distribution manifold and related method

Abstract

This provides an improved method for connecting a cassette assembly to the associated pressure distribution manifold. [Solution] A fluid handling cassette containing multiple diaphragm valves and pumps is configured such that its operating ports are located along the thin-walled or narrow end of the cassette. The operating passages within the cassette lead from the operating ports to the operating chambers of the valves and pumps located in the space between the plates constituting the cassette. Each plate has a nominal thickness that is thin enough to provide a rigid ceiling for the operating passages but thin enough to minimize the overall thickness of the cassette. The cassette can be inserted into and removed from an operating receptacle or manifold by its narrow end. Multiple such cassettes can be stacked together or spaced apart from one another to form a cassette assembly, providing a convenient method for inserting and removing the cassette assembly from its operating receptacle.

Description

Technical Field

[0001] The present disclosure generally relates to improvements in the design and structure of fluid pumps or mixing cassettes, cassette assemblies, their components, and related devices.

Background Art

[0002] Fluid processing cassettes including diaphragm pumps and / or valves can be actuated hydraulically or pneumatically. In some examples, the cassette is designed to be fluidly connected to a pneumatically actuated manifold having electromechanical valves that selectively distribute positively or negatively pressurized gas or air to the cassette. A programmable electronic controller can be used to control the electromechanical valves to selectively supply positive or negative pneumatic pressure to various pumps or valves of the cassette in a predetermined manner.

[0003] Some fluid handling cassettes may have a substantially planar shape, with thin or narrow sides adjacent to wider sides, where the thin or narrow sides have a thickness relatively smaller than the overall width of the wider side of the cassette. Liquid inlet and outlet ports can be incorporated into the ends or thin sides of the cassette. However, in many of these devices, the cassette's operating port is located on the cassette's face or wider side directly above the working chamber of the controlled pump or valve. This generally provides the shortest route for the working passage within the cassette from the external cassette operating port to the working chamber and diaphragm of the pump or valve inside the cassette. Furthermore, often the cassette's pumping station or valve station or area (including either the working chamber on one side or the liquid conveying chamber on the opposite side) may be formed by spherical or hemispherical chamber walls extending over the plane of the cassette surface, which in some applications makes the entire cassette thicker than desired. In other cases, the pump module may include a set of blocks sandwiched together with pneumatically operated or fluid passages embedded within one or more blocks, or stacked together. This configuration may also result in an overall device thickness greater than desired for a particular application. In some applications, multiple fluid handling cassettes may need to be mounted adjacent to each other in a confined space. In these cases, it may be desirable to place many cassettes adjacent to each other, stack them on top of each other, or at least place them close together with their wide sides facing each other. It may be particularly desirable to reduce or minimize the thickness of the individual cassettes that make up these assemblies.

[0004] It may be advantageous to configure the pump cassette to plug directly into its associated pressure distribution manifold (e.g., a manifold that selectively delivers pneumatic pressure to the pump cassette under the control of an electronic controller). In conventionally disclosed embodiments of hemodialysis systems using pneumatically operated self-contained pump cassettes, the pump cassette is connected to the corresponding pneumatic manifold via a flexible tube, which presents significant challenges during assembly and operation. If the pump cassette can be located near its associated manifold, a direct plug-in connection between the two offers significant advantages. In these circumstances, it is particularly advantageous to have a compact manifold that enables a direct interface to the pump cassette, positioned so that the cassette or cassette assembly can be plugged into and unplugged from the manifold's operating port with minimal effort.

[0005] In the design and operation of pneumatic distribution manifolds, the use of binary pressure control valves instead of continuously variable orifice valves offers significant advantages in both cost and reliability. However, in this case, controlling the pressure supply to individual cassette pumps or valves by the binary pressure control valves presents additional challenges that must be overcome. A sufficiently robust electronic controller can be programmed using control algorithms to control the period and duration of binary valve operation, thereby achieving precise control of the associated pneumatically operated pumps or valves. [Overview of the project]

[0006] In one embodiment, the pump and / or valve cassette has a relatively planar shape, with wider sides adjacent to thinner, narrower sides or ends. The pump and / or valve cassette includes an intermediate plate positioned between two outer plates. The first outer plate faces a first side of the intermediate plate, and the second outer plate faces a second side opposite the intermediate plate. The first outer plate is spaced apart from the intermediate plate to form a first inter-plate space. The second outer plate is spaced apart from the intermediate plate to form a second inter-plate space. The thicknesses of the first and second outer plates are limited to a thickness sufficient to give the plates rigidity and to provide a sealing surface against the opposing passage walls on both sides of the intermediate plate. In some embodiments, the thickness of each outer plate, together with the thickness of the intermediate plate between them, defines the overall thickness of the cassette. In other embodiments, the liquid inlet and outlet ports protrude from the outer surface of the cassette, thereby increasing the overall thickness of the cassette. The cassette may include one or more pump stations or regions and two or more valve stations or regions. The overall width of the cassette can be determined by the number and size of pump or valve stations. The stroke volume of an onboard pump is a function of the diameter of the pump station and its associated diaphragm, and the depth of the diaphragm's range of motion, defined by the depth of the passage walls of the intermediate plate, thereby determining the thickness of the cassette and the width of its broad sides. For any given pump or valve station, the intermediate plate includes an operating side and an opposite liquid side, with the operating side holding the pump diaphragm or valve diaphragm. The operating passages within the cassette to individual pumps or valve stations are housed in intermediate plate passages in a first inter-plate space and can extend substantially parallel to the width of the cassette. The liquid passages within the cassette are housed in intermediate plate passages in a second inter-plate space and generally extend parallel to the width of the cassette, except in some cases where the liquid passages connect to the inlet or outlet of the cassette.In this configuration, the first and second outer plates primarily function to provide a roof or limiting wall over the individual operating and liquid transfer valve or pump areas.

[0007] In one embodiment, the fluid handling cassette may include an intermediate plate positioned between a first plate and a second plate, the plate having length, width, and thickness, with a first side of the intermediate plate facing the first plate and a second side of the intermediate plate facing the second plate. The first plate is spaced apart from the intermediate plate defining the width of the first inter-plate space, and the second plate is spaced apart from the intermediate plate defining the width of the second inter-plate space. The ends of the cassette have a cassette thickness defined by adding the width of the first and second inter-plate spaces to the thickness of each plate, and the faces of the cassette are defined by the length and width of the first or second plate. The intermediate plate may include a pump station formed by a pump diaphragm and a first side of the intermediate plate, the pump diaphragm seating against the first side of the intermediate plate and having a range of motion defined by the width of the first inter-plate space. The pump operating passage extends parallel to the surface of the cassette in the first inter-plate space, and the pump operating passage connects the pump operating chamber, which is bounded by the first plate and the pump diaphragm, to the cassette pump operating port located at the first end of the cassette in the first inter-plate space. First and second pump fluid ports in the pump station may fluidly connect the individual first and second fluid passages in the second inter-plate space to the pumping chamber formed by the pump diaphragm and the first side surface of the intermediate plate. Pump fluid ports in the pump station may fluidly connect the fluid passages in the second inter-plate space to the pumping chamber formed by the pump diaphragm and the first side surface of the intermediate plate. Alternatively, an opening may be provided in the intermediate plate in the pump station, which allows the pump diaphragm to move from the first plate to the second plate when actuated by positive or negative pressure supplied through the pump operating passage. The plates (first, intermediate, and second) have insufficient thickness to allow fluid passages or working passages to travel through the plates in a direction parallel to the surface of the cassette.The fluid passage extends into a second inter-plate space and can be fluidly connected to a pumping chamber formed by the pump diaphragm and the first side surface of the intermediate plate, the connection being made via one or more pump fluid ports in the intermediate plate, the fluid passage extends parallel to the surface of the cassette in the second inter-plate space, and the fluid passage connects the pumping chamber to a cassette fluid port located at the first or second end of the cassette in the second inter-plate space.

[0008] In one embodiment, the fluid handling cassette may include an intermediate plate positioned between a first plate and a second plate, the plate having length, width, and thickness, with a first side of the intermediate plate facing the first plate and a second side of the intermediate plate facing the second plate. The first plate is spaced apart from the intermediate plate defining the width of the first inter-plate space, and the second plate is spaced apart from the intermediate plate defining the width of the second inter-plate space. The ends of the cassette have a cassette thickness defined by adding the widths of the first and second inter-plate spaces to the thickness of each plate, and the faces of the cassette are defined by the length and width of the first or second plate. The intermediate plate may include a valve station formed by a valve diaphragm and a first side of the intermediate plate, the valve diaphragm seating against the first side of the intermediate plate and having a range of motion defined by the width of the first inter-plate space. The valve operating passage extends parallel to the surface of the cassette in the first inter-plate space, and the valve operating passage connects a valve operating chamber, bounded by the first plate and the valve diaphragm, to a cassette valve operating port located at the first end of the cassette in the first inter-plate space. The first and second valve fluid ports in the valve station may fluidly connect the individual first and second fluid passages in the second inter-plate space to a valve fluid chamber formed by the valve diaphragm and the first side of the intermediate plate. One or both valve fluid ports may include a raised valve seat for sealing the valve diaphragm over the first or second valve fluid port when positive pressure is applied to the valve diaphragm through the valve operating passage. The first fluid passage is fluidly isolated from the second fluid passage, except through the first and second valve fluid ports.The fluid passage extends into a second inter-plate space and can be fluidly connected to a valve fluid chamber formed by the valve diaphragm and the first side surface of the intermediate plate, the connection being made via two valve fluid ports in the intermediate plate, the fluid passage extends parallel to the surface of the cassette in the second inter-plate space, and the fluid passage connects the valve fluid chamber to a cassette fluid port located at the first or second end in the second inter-plate space.

[0009] In another embodiment, the fluid handling cassette may include an intermediate plate positioned between a first plate and a second plate, the plate having length, width, and thickness, with a first side of the intermediate plate facing the first plate and a second side of the intermediate plate facing the second plate. The first plate is spaced apart from the intermediate plate defining the width of the first inter-plate space, and the second plate is spaced apart from the intermediate plate defining the width of the second inter-plate space. The ends of the cassette have a cassette thickness defined by adding the widths of the first and second inter-plate spaces to the thickness of each plate, and the faces of the cassette are defined by the length and width of the first or second plate. The intermediate plate may include a pump station formed by a pump diaphragm and a first side of the intermediate plate, the pump diaphragm seating against the first side of the intermediate plate and having a range of motion defined by the width of the first inter-plate space. The intermediate plate may include first and second valve stations, each formed by a valve diaphragm and a first side surface of the intermediate plate, the valve diaphragm seating against the first side surface of the intermediate plate and having a range of motion defined by the width of the first inter-plate space. A pump operating passage for the pump station and valve operating passages for each of the first and second valve stations are provided. The pump operating passage extends parallel to the surface of the cassette in the first inter-plate space, and connects a pump operating chamber, bounded by the first plate and the pump diaphragm, to a cassette pump operating port located at the first end of the cassette in the first inter-plate space. Each of the valve operating passages extends parallel to the surface of the cassette in the first inter-plate space, and connects a valve operating chamber, bounded by the first plate and the valve diaphragm, to a cassette valve operating port located at the first end of the cassette in the first inter-plate space.Each of the two valve stations may be provided with inlet and outlet valve fluid ports, and each of the pump stations may be provided with one or more pump fluid ports, each of the valves and pump fluid ports fluidly connects a fluid passage in a second inter-plate space to a pumping chamber formed by a pump diaphragm and a first surface of an intermediate plate, and to a valve fluid chamber in each valve station formed by the corresponding valve diaphragm and the first surface of an intermediate plate. The fluid passage has a flow path through the inlet and outlet valve fluid ports and one or more pump fluid ports, and each of the valve operating passages in the pump operating chamber and valve operating chamber allows for unidirectional flow of fluid through the fluid passage by selective operation. The fluid passage extends into a second inter-plate space and is fluidly connected to a pumping chamber formed by a pump diaphragm and a first side of an intermediate plate, the connection being made via a pump fluid port in the intermediate plate, the fluid passage is fluidly connected to a valve fluid chamber of each valve station formed by a corresponding valve diaphragm and a first side of an intermediate plate, the connection being made via two valve fluid ports in the intermediate plate, the fluid passage extends parallel to the surface of the cassette in the second inter-plate space, the fluid passage connects the pumping chamber and each valve fluid chamber to a cassette fluid inlet port and a cassette fluid outlet port located at the first or second end of the cassette in the second inter-plate space. The cassette fluid inlet port and cassette fluid outlet port are located at the second end of the cassette, the cassette pump operating port and cassette valve operating port are configured to be directly inserted into a mating operating receptacle located outside the cassette, and the fluid inlet port and fluid outlet port are configured to be connected to a fluid source or fluid destination located outside the cassette via flexible or malleable tubing.A fluid passage extends into a second inter-plate space and is fluidically connected to a pumping chamber formed by a pump diaphragm and a first side of an intermediate plate, the connection being made via a pump fluid port in the intermediate plate. The fluid passage is also fluidly connected to a valve fluid chamber at each valve station, each valve fluid chamber formed by a corresponding valve diaphragm and a first side of an intermediate plate, the connection being made via two valve fluid ports in the intermediate plate. The fluid passage extends into the second inter-plate space parallel to the surface of the cassette and connects the pumping chamber and each valve fluid chamber to a cassette fluid inlet port and a cassette fluid outlet port, the cassette fluid inlet port and cassette fluid outlet port emerging from the cassette via a rigid conduit that originates from the intermediate plate and penetrates the surface of the cassette, passing through a first or second outer plate.

[0010] In further embodiments, a plurality of walls may be formed on the first and second sides of the intermediate plate, the walls being arranged to combine with the first and second plates within the cassette to form an operating passage or fluid passage. A first type of wall may include parallel walls defining an operating passage or fluid passage, a second type of wall may include a circumferential surrounding wall defining a pump operating station or valve operating station, and a third type of wall may include adjacent end walls defining a passage end through which a valve fluid port or pump fluid port penetrates the intermediate plate. The first plate may include one or more circumferential valve or pump diaphragm retainers configured to fit within the circumferential surrounding walls of opposing intermediate plates defining a pump operating station or valve operating station, the retainers being arranged to clamp the peripheral bead or rim of the associated diaphragm located within the pump or valve station of the intermediate plate. The retainers may include holes, perforations, or slots to allow the transfer of working fluid or gas between the valve or pump operating chamber enclosed by the retainer and the associated operating passage. The first plate includes an elongated rib configured to be positioned within the mating passage of the intermediate plate, the cross-sectional size and length of the rib being determined to adjust the volume of the working passage between the cassette's operating port and the associated valve or pump operating chamber to a predetermined value.

[0011] In another embodiment, the fluid handling cassette may include an intermediate plate positioned between a first plate and a second plate, the plate having length, width, and thickness, with a first side of the intermediate plate facing the first plate and a second side of the intermediate plate facing the second plate, the first plate spaced apart from the intermediate plate defining the width of the first inter-plate space, and the second plate spaced apart from the intermediate plate defining the width of the second inter-plate space. The ends of the cassette have a cassette thickness defined by adding the width of the first and second inter-plate spaces to the thickness of each plate, and the faces of the cassette are defined by the length and width of the first or second plate. The intermediate plate includes first and second valve stations, the first valve station being formed by a first valve diaphragm and a first side surface of the intermediate plate, and the second valve station being formed by a second valve diaphragm and a second side surface of the intermediate plate, the first valve diaphragm seating on the first side surface of the intermediate plate and having a range of motion defined by the width of the first inter-plate space, and the second valve diaphragm seating on the second side surface of the intermediate plate and having a range of motion defined by the width of the second inter-plate space. A first valve operating passage for the first valve station extends parallel to the surface of the cassette in the first inter-plate space, and a second valve operating passage for the second valve station extends parallel to the surface of the cassette in the second inter-plate space. The first valve operating passage connects a first valve operating chamber, bounded by a first plate and a first valve diaphragm, to a first cassette valve operating port located at the first end of the cassette within the first inter-plate space, and the second valve operating passage connects a second valve operating chamber, bounded by a second plate and a second valve diaphragm, to a second cassette valve operating port located at the first end of the cassette within the second inter-plate space.

[0012] In another embodiment, the fluid handling cassette may include an intermediate plate positioned between a first plate and a second plate, the plate having length, width, and thickness, with a first side of the intermediate plate facing the first plate and a second side of the intermediate plate facing the second plate. The first plate is spaced apart from the intermediate plate that defines the width of the first inter-plate space, and the second plate is spaced apart from the intermediate plate that defines the width of the second inter-plate space. The ends of the cassette have a cassette thickness defined by adding the width of the first and second inter-plate spaces to the thickness of each plate, and the faces of the cassette are defined by the length and width of the first or second plate. The intermediate plate includes first and second pump stations, the first pump station being formed by a first pump diaphragm and a first side surface of the intermediate plate, and the second pump station being formed by a second pump diaphragm and a second side surface of the intermediate plate, the first pump diaphragm seating on the first side surface of the intermediate plate and having a range of motion defined by the width of the first inter-plate space, and the second pump diaphragm seating on the second side surface of the intermediate plate and having a range of motion defined by the width of the second inter-plate space. A first pump operating passage for a first pump station extends parallel to the surface of the cassette in a first inter-plate space, and a second pump operating passage for a second pump station extends parallel to the surface of the cassette in a second inter-plate space. The first pump operating passage connects a first pump operating chamber, bounded by a first plate and a first pump diaphragm, to a first cassette pump operating port located at the first end of the cassette in the first inter-plate space. The second pump operating passage connects a second pump operating chamber, bounded by a second plate and a second pump diaphragm, to a second cassette pump operating port located at the first end of the cassette in the second inter-plate space.

[0013] In another embodiment, the fluid handling cassette assembly may include an intermediate cassette interposed between a first outer cassette and a second outer cassette, each cassette including an intermediate plate positioned between a first plate and a second plate, the plate having length, width, and thickness, with a first side of the intermediate plate facing the first plate and a second side of the intermediate plate facing the second plate. The first plate is spaced apart from the intermediate plate defining the width of the first inter-plate space, and the second plate is spaced apart from the intermediate plate defining the width of the second inter-plate space. The ends of the cassette have a cassette thickness defined by adding the width of the first and second inter-plate spaces to the thickness of each plate, and the faces of the cassette are defined by the length and width of the first or second plate. Multiple diaphragm valves or pumps, including valve or pump operating chambers, are connected to operating passages, which extend parallel to the surface of the cassette within a first or second inter-plate space and terminate in individual cassette valve or pump operating ports at a first end of the cassette between the first or second inter-plate spaces. A fluid handling pod is located in the inter-cassette space between the intermediate cassette and the first or second cassette, and the pod has fluid connections to the fluid passages in the intermediate, first or second cassette via fluid conduits penetrating the surfaces of the intermediate, first or second cassette. The first ends of the intermediate, first and second cassettes are located on the first side of the cassette assembly so that the cassette valve or pump operating ports are configured to be inserted into or withdrawn from an operating port receptacle assembly facing the first side of the cassette assembly. The fluid handling pod may include a diaphragm pump pod having actuation and fluid connections to actuation passages and fluid passages within the intermediate, first, or second cassette via actuation conduits and fluid conduits penetrating the faces of the intermediate, first, or second cassette. The actuation conduits of the diaphragm pump pod connect to actuation passages in the first or second interplate space of the intermediate, first, or second cassette and have continuous connections to cassette actuation ports for the diaphragm pump pod located at the first end of the intermediate, first, or second cassette.The fluid conduits of the diaphragm pump pod connect to fluid passages in the inter-plate space of the intermediate, first, or second cassette and to diaphragm valves within the cassette, and the operating passages of the diaphragm valves may connect to cassette operating ports for the diaphragm valves located at the first end of the intermediate, first, or second cassette. The fluid conduits in any of these configurations may be rigid. Multiple fluid handling pods may be positioned between the intermediate cassette and the first cassette, and between the intermediate cassette and the second cassette, and the associated fluid conduits of the multiple fluid handling pods may be rigid to provide structural support to the cassette assembly. The cassette assembly frame may be configured to increase the structural rigidity of the cassette assembly, and the cassette assembly frame may include a rigid support plate on the second side of the cassette assembly opposite to the first side of the cassette assembly, and the support plate may be configured to engage with a cassette loading device opposite to the operating port receptacle.

[0014] In another embodiment, the fluid handling cassette assembly may include an intermediate cassette interposed between a first outer cassette and a second outer cassette, each cassette including an intermediate plate positioned between a first plate and a second plate, the plate having length, width, and thickness, with a first side of the intermediate plate facing the first plate and a second side of the intermediate plate facing the second plate. The first plate is spaced apart from the intermediate plate defining the width of the first inter-plate space, and the second plate is spaced apart from the intermediate plate defining the width of the second inter-plate space. The ends of the cassette have a cassette thickness defined by adding the width of the first and second inter-plate spaces to the thickness of each plate, and the faces of the cassette are defined by the length and width of the first or second plate. Multiple diaphragm valves or pumps may include valve or pump operating chambers connected to operating passages, the operating passages extending parallel to the surface of the cassette within a first or second inter-plate space and terminating at a first end of the cassette between the first or second inter-plate spaces with individual cassette valve or pump operating ports. A first fluid handling pod may be located in the inter-cassette space between an intermediate cassette and a first or second cassette. The fluid handling pod has fluid connections to fluid passages within the intermediate, first, or second cassette via fluid conduits penetrating the surface of the intermediate, first, or second cassette. A second fluid handling pod may include a diaphragm pump pod having operating and fluid connections to operating passages and fluid passages within the intermediate, first, or second cassette via operating conduits and fluid conduits penetrating the surface of the intermediate, first, or second cassette. The first ends of the intermediate, first, and second cassettes are positioned on the first side of the cassette assembly, and the cassette valve or pump operating port is configured to be inserted into or withdrawn from an operating port receptacle assembly facing the first side of the cassette assembly.The working conduit of the diaphragm pump pod may have a working passage in the first or second interplate space of the intermediate, first, or second cassette, and a continuous connection to a cassette operating port for the diaphragm pump pod located at the first end of the intermediate, first, or second cassette. The fluid conduit of the diaphragm pump pod may have a fluid passage in the first or second interplate space of the intermediate, first, or second cassette, and a connection to a diaphragm valve in the cassette, and the working passage of the diaphragm may have a cassette operating port for the diaphragm valve located at the first end of the intermediate, first, or second cassette. The fluid conduit may be rigid. Multiple fluid handling pods may be provided between the intermediate cassette and the first cassette, and between the intermediate cassette and the second cassette, and the associated fluid conduits of the multiple fluid handling pods may be rigid to provide structural support to the cassette assembly. The cassette assembly frame can be configured to increase the structural rigidity of the cassette assembly, and the cassette assembly frame includes a rigid support plate on a second side of the cassette assembly opposite to a first side of the cassette assembly, and the support plate is configured to engage with the cassette loading device on the opposite side of the actuation port receptacle.

[0015] In another aspect of the present invention, the manifold adapter is configured to connect a pressure distribution manifold to a fluid processing cassette assembly. The housing has a first side including a first set of transfer ports configured to connect to the operating output ports of the manifold, and a second side on the opposite side including a second set of transfer ports configured to connect to the operating input ports of the cassette assembly. The first set of transfer ports includes a first spatial array configured to match the spatial array of the operating output ports of the manifold. The second set of transfer ports includes a second spatial array configured to match the spatial array of the operating input ports of the cassette assembly, wherein the first spatial array of transfer ports is distinct from the second spatial array of transfer ports. The first spatial array may cover an area having a first length and a first width on the first side of the adapter housing, and the second spatial array may cover an area having a second length and a second width on the second side of the adapter housing. The second length is greater than the first length so that the housing of the manifold adapter protrudes from the side of the manifold. The second side of the housing may include an elastomer wiper gasket consisting of multiple wiper seals, each of which is associated with a transfer port on the second side of the adapter housing. The wiper gasket may be embedded beneath the upper plate of the adapter housing.

[0016] In another embodiment, the seating device is described for a cassette having a plug-in side and a mounting side on the opposite side. The seating device comprises a fixed frame member connected to a movable cassette mount by a plurality of link mechanisms located on a first side of the cassette mount and a second side on the opposite side of the cassette mount. The link mechanisms on the first side of the cassette mount are connected to a first fixed flange of the fixed frame member, and the link mechanisms on the second side of the cassette mount are connected to a second fixed flange of the fixed frame member. Each of the plurality of link mechanisms may include a swing arm having a first end pivotably coupled to the fixed flange and a second end coupled to an elongated slot of the cassette mount. The second end of the swing arm is configured to move along an arc-shaped path to move the cassette mount, and the elongated slot restricts the movement of the cassette mount by the swing arm to linear motion toward or away from the fixed frame member. The cassette mount may include a first movable flange and a first rail on a first side of the cassette mount, and a second movable flange and a second rail on a second side of the cassette mount. Each of the movable flanges may have a surface substantially parallel to the direction of movement of the cassette mount, and elongated slots may be formed in the movable flange and oriented perpendicular to the direction of movement of the cassette mount, and the first and second rails may be configured to hold the mounting side of the cassette. A handle assembly may be pivotably connected to the cassette mount so as the handle of the handle assembly moves away from the fixed frame member, causing the cassette mount to move away from the fixed frame member, and as the handle moves toward the fixed frame member, causing the cassette mount to move toward the fixed frame member.The pivot connections of the handle assembly may include a first pivot connection of the first handle arm to a first fixed flange, a second pivot connection of the second handle arm to a second fixed flange, a third pivot connection of the first handle arm to a handle swing arm connected to a first movable flange of the cassette mount, and a fourth pivot connection of the second handle arm to a handle swing arm connected to a second movable flange of the cassette mount. The first and third pivot connections and the second and fourth pivot connections may be spaced apart from each other on the first and second handle arms. The third fixed flange of the fixed frame member may face the handle assembly and be substantially perpendicular to the first and second fixed flanges. The handle assembly may include a spring plunger configured to engage with a hole or recess in the third fixed flange so that the cassette mount is locked in a stowed position when the handle of the handle assembly moves toward the fixed frame member. [Brief explanation of the drawing]

[0017] Non-limiting embodiments of the present invention will be described by reference to the accompanying drawings, some of which are schematic and not intended to be drawn to scale. In the drawings, each identical or substantially identical component shown is usually represented by a single number. For clarity, not all components are labeled in all drawings, nor are all components of each embodiment of the present invention shown where illustration is not necessary for those skilled in the art to understand the invention. [Figure 1A-1B] This is a schematic cross-sectional view of an embodiment of a pump cassette during the filling and dispensing processes. [Figure 2A-2B] This is a schematic cross-sectional view of another embodiment of the pump cassette during the filling and dispensing processes. [Figure 3A-3B] This is a schematic cross-sectional view of an exemplary diaphragm valve in operation. [Figure 4A-4B] This is a schematic cross-sectional view of another embodiment of the pump cassette in operation. [Figure 5A-5B]Schematic cross-sectional view of an exemplary pump cassette during operation with an additional mechanism. [Figure 6] Perspective view of an exemplary pump or valve cassette. [Figure 7] Front perspective view of the pump or valve cassette shown in FIG. 6. [Figure 8] Perspective view of the inside of the outer plate of the exemplary cassette illustrated in FIGS. 6 and 7. [Figure 9] Perspective view of the working side of the intermediate plate of the exemplary cassette illustrated in FIGS. 6, 7 and 8. [Figure 10] Enlarged view of the pump station and valve station on the working side of the intermediate plate shown in FIG. 9. [Figure 11] Perspective view of the flow path side of the intermediate plate of an exemplary pump or valve cassette. [Figure 12] Perspective view of another embodiment of a pump or valve cassette. [Figure 13] Perspective view of the first side of the intermediate plate of the exemplary cassette illustrated in FIG. 12. [Figure 14] Perspective view of the second side of the intermediate plate shown in FIG. 13. [Figure 15] Rear perspective view of the cassette assembly. [Figure 16] Front perspective view of the cassette assembly shown in FIG. 15. [Figure 17A] Front and rear perspective views of another embodiment of a cassette assembly. [Figure 17B] Front and rear perspective views of another embodiment of a cassette assembly. [Figure 18] Exploded view of a conventional exemplary cassette assembly. [Figure 19] Side view of the assembled cassette assembly of FIG. 18 showing the pneumatic actuating lines and associated connectors of the assembly. [Figure 20] Perspective view of another embodiment of a cassette assembly fixed to a frame assembly. [Figure 21] Figure 20 is an exploded view of the frame assembly shown. [Figure 22A] Front and rear perspective views of the top plate of an exemplary frame assembly. [Figure 22B] Front and rear perspective views of the top plate of an exemplary frame assembly. [Figure 23] This is a front perspective view of a hemodialysis machine. [Figure 24] Figure 23 is a front perspective view of the housing of the hemodialysis machine shown. [Figure 25] Figure 24 is a rear perspective view of the housing. [Figure 26] This is a schematic diagram of an example pressure distribution manifold. [Figure 27] This is a schematic diagram of an example pressure distribution manifold. [Figure 28] This is a schematic diagram of an example pressure distribution manifold. [Figure 29] This is a schematic diagram of an example pressure distribution manifold. [Figure 30] Figure 24 is a top perspective view of the housing surrounding the cassette assembly, separated from the corresponding manifold assembly. [Figure 31] Figure 30 shows a top perspective view of the housing, where the cassette assembly is connected to the corresponding manifold assembly. [Figure 32] This is a rear perspective view of an exemplary pressure distribution manifold and associated interface adapter. [Figure 33] Figure 32 is an exploded view of the pressure distribution manifold shown. [Figure 34] This is a perspective view of an exemplary pressure distribution manifold and associated sensor substrate. [Figure 35] Figure 34 is a perspective view of the lower block of the pressure distribution manifold shown. [Figure 36] Figure 34 shows lower and upper perspective views of the upper block of the pressure distribution manifold. [Figure 37] Figure 34 shows lower and upper perspective views of the upper block of the pressure distribution manifold. [Figure 38] This is a schematic diagram of the flow path configuration of the pneumatic passages in an exemplary pressure distribution manifold. [Figure 39] This is a perspective view of an exemplary pneumatic passage within a pressure distribution manifold. [Figure 40] Figure 39 is a perspective view of an exemplary pneumatic passage arrangement within a pressure distribution manifold. [Figure 41] This is a schematic diagram of the flow path configuration of the pneumatic passages in an exemplary pressure distribution manifold. [Figure 42] A perspective view of another exemplary pneumatic passage within a pressure distribution manifold. [Figure 43] Figure 42 is a perspective view of an exemplary pneumatic passage arrangement within a pressure distribution manifold. [Figure 44] This is a rear perspective view of the hemodialysis machine housing, showing the arrangement of the pressure distribution manifold. [Figure 45] This is a front perspective view of a hemodialysis machine housing, illustrating the installation of an exemplary manifold adapter. [Figure 46] This is a front left perspective view of an exemplary cassette assembly positioned on top of the housing and aligned with the manifold adapter. [Figure 47] This is a perspective view of an exemplary pneumatic distribution manifold located below the housing notch for the manifold adapter. [Figure 48] This is a rear perspective view of a hemodialysis machine housing, illustrating the installation of an exemplary pressure distribution device and interface adapter. [Figure 49] This is a front perspective view of a hemodialysis machine housing, illustrating the installation of an exemplary interface adapter. [Figure 50] This is a partial cutaway of a hemodialysis machine housing, showing an exemplary cassette loading assembly mounted on the ceiling of the housing. [Figure 51] This is a perspective view of an exemplary manifold adapter rail. [Figure 52] This is a partially disassembled top perspective view of an exemplary manifold adapter positioned on a pressure distribution manifold. [Figure 53] This is a partially exploded view of the manifold adapter in Figure 52, seen from below. [Figure 54] This is a plan view of an example wiper gasket for a manifold adapter. [Figure 55] Figure 54 is a cross-sectional view showing the wiper gasket. [Figure 56] This is an illustrative downward perspective view of a cassette loading assembly with the operating handle in the raised (released) position. [Figure 57] This is an illustrative front perspective view of a cassette loading assembly with the operating handle in the lowered (engaged) position. [Figure 58] Figure 57 is a downward perspective view of an exemplary cassette loading assembly with the operating handle in the lowered position. [Figure 59] Figures 57 and 58 show a rear perspective view of an exemplary cassette loading assembly with the operating handle in the lowered position. [Figure 60] This is a schematic diagram of the fluid flow path inside a hemodialysis machine. [Figure 61] This is a graph showing the pressure fluctuations within the operating chamber of the pump in a hemodialysis machine. [Figure 62] This is a graph showing the pressure fluctuations within the operating chamber of the pump in a hemodialysis machine. [Figure 63] This is an illustrative flowchart of an algorithm for controlling the pressure in the operating chamber of a pneumatically operated pump. [Figure 64] This is an illustrative flowchart of an alternative pressure control algorithm for a pneumatically operated pump. [Figure 65] This is an exemplary flowchart for a stroke end detection algorithm for an exemplary pneumatically operated pump. [Figure 66]This is an illustrative flowchart of an obstruction detection algorithm for fluid paths in a diaphragm-based pump system. [Figure 67] This is an illustrative flowchart of an algorithm for determining resistance to the flow during the pumping filling process. [Figure 68] This is a schematic diagram of the fluid flow path in an exemplary hemodialysis system. [Figure 69] Figure 68 is a schematic diagram of an independent section of the fluid flow path in the hemodialysis system shown. [Figure 70] This is a diagram illustrating the sterilization procedure for a hemodialysis system. [Figure 71] This is a state diagram showing temperature control before and during the sterilization procedure. [Modes for carrying out the invention]

[0018] Cassette with liquid passages and pneumatic passages in a flat surface In some pumping applications, it is advantageous to position the operating ports of a fluid-pressure or pneumatically operated pump or valve cassette on the ends, thin-walled, or narrow sides of the cassette, rather than on the wide sides of the cassette. This allows the cassette to be inserted into a receptacle containing an array of operating ports associated with a pressure supply manifold, rather than on the narrow sides. This can maximize the functionality that the pump / valve cassette can perform within a limited space. In some situations, overall space constraints may favor minimizing the total thickness of the cassette. This can be achieved by making the cassette thicker than the range of motion of the sealed diaphragm. Ideally, each outer plate of the cassette primarily functions as the roof or end wall of the pump or valve operating or fluid transport chamber or passage, and its thickness is insufficient to completely enclose any fluid or operating passage extending nearly parallel to the faces or wide sides of the cassette. The working passage is configured to extend within the space between the intermediate plate and the outer plate (e.g., the first outer plate) of the cassette, within the interplate space that defines the maximum range of motion of one or more diaphragms of the cassette. The width of the interplate space (and thus the maximum range of motion of the flexible membrane or diaphragm) can be predetermined by the height of the passage walls formed on the working side and / or liquid transport side of the cassette intermediate plate. The height of the passage wall on one side of the intermediate plate may differ from the height of the passage wall on the opposite side of the intermediate plate. For example, to accommodate a desired fluid flow rate, the passage wall on the liquid side of the intermediate plate can be made higher to provide a larger cross-sectional area of ​​the liquid transport passage, while the cross-sectional requirements (and thus the passage wall height) of the working passage on the working side of the intermediate plate may be smaller.

[0019] Figures 1A and 1B schematically show a cross-section of the cassette 10 near the end of the filling stroke and near the end of the dispensing stroke, respectively. The intermediate plate 12 is located between the first outer plate 14 and the second outer plate 16. The flexible diaphragm 18 is located in the first inter-plate space 20, and the liquid flow path is located in the second inter-plate space 22. To reduce the thickness of the pump and / or valve cassette, any working passage preferably extends into the first inter-plate space 20, which is a space defined by the depth of the range of motion, travel depth, or linear range E over which the diaphragm moves between the intermediate plate 12 and the first outer plate 14. For an onboard diaphragm pump, its stroke volume correlates with the depth of the range of motion E of the diaphragm 18 and the effective surface area occupied by the diaphragm on the broad side of the cassette. The preferred depth of the diaphragm's range of motion E may also depend on how efficiently the diaphragm's stroke volume can be increased by increasing its effective surface area. In this embodiment, two pump chamber liquid ports 24a, 24b are shown, representing an inlet and an outlet, each port connected to a separate fluid passage in the interplate space 22, which is schematically separated by a wall 38 (the direction of the liquid flow shown is arbitrary and depends on which liquid line is open or closed by a downstream valve during the diaphragm's filling or discharging stroke). In another embodiment, as shown in Figures 2A and 2B, a single pump chamber liquid port 24c (or two or more such ports) may be used, where the pump chamber liquid port 24c alternates between an inlet and an outlet port depending on which downstream valve is open or closed in a single liquid line in the interplate space 22. When the volume of the working chamber 26 is minimum, the corresponding pump chamber 28 is maximum (filling stroke, see Figures 1A and 2A). When the volume of the working chamber 26 is at its maximum, the volume of the corresponding pump chamber 28 is at its minimum (see delivery stroke, Figures 1B and 2B).When the depth E of the range of motion of the diaphragm on the cassette is selected, the thickness T of the cassette can be reduced by avoiding placing the actuation port directly above the actuated diaphragm (as in prior art designs). This is achieved by placing the actuation port on a thin or narrow side of the cassette and extending the actuation passage to the individual diaphragms in a first inter-plate space 20 within the cassette 10. This space is defined by an intermediate plate 12 on which the diaphragm 18 sits and a first outer plate 14 that provides a cover or roof for the actuation chamber 26 for each diaphragm 18. Surrounding each diaphragm is a wall 30 that spans the inter-plate space 20, and together with the outer plate 14, the wall 30 completes each actuation chamber 26, except for the actuation port or actuation window 32 that connects the actuation chamber 26 to its corresponding actuation passage (represented by an arrow in the first inter-plate space 20). The operating passage extends within the inter-plate space 20 to the outer edge or narrow side of the cassette, where it terminates as a cassette operating port (see, for example, Figure 9). Note that the operating passage can be smaller than the depth provided by the inter-plate space 20, depending on the specified range of motion depth E for the diaphragm 18. To minimize the overall thickness T of the cassette 10 for a given specified range of motion depth E of the diaphragm, the nominal thickness P of each plate 12, 14, 16 can be minimized (within the constraints of structural rigidity and any constraints imposed in achieving proper welding or bonding of the outer plates to the passage walls of the intermediate plates). Depending on the fluid flow rate requirements, the thickness of the cassette can also be minimized by reducing the depth of the fluid passage in the second inter-plate space 22 (i.e., the height of the passage walls).

[0020] The overall thickness T of the cassette depends on the amount of depth required by the liquid flow path or liquid passage on the opposing side of the intermediate plate 12 of the cassette 10 within the second inter-plate space 22. In the pump shown in Figures 1A to 2B and the valve shown in Figures 3A and 3B, the required depth of the liquid passage determines the depth of the second inter-plate space 22. Depending on the specified liquid flow rate for the cassette, the second inter-plate space 22 may have a depth L that is substantially smaller than the depth E of the first inter-plate space 20.

[0021] As shown in Figures 3A and 3B, for any given diaphragm valve station, there are at least two fluid passages (a first passage terminating at valve port 34a of the intermediate plate 12, and a second passage terminating at valve port 34b of the intermediate plate 12) (in some embodiments, multiple fluid passages may terminate at separate valve ports in the intermediate plate of a single valve station). As shown in Figures 3A and 3B, the depth E of the range of motion is determined, in the case of a diaphragm valve, by the degree of slack required to allow the diaphragm 18 to lift away from the fluid ports 34a,b designed to close. The valve diaphragm 36 may move away from ports 34a,b under negative operating pressure to allow fluid flow, as shown in Figure 3A, or move to close ports 34a,b under positive operating pressure to block fluid flow, as shown in Figure 2B. The separate fluid passages within the valve station of the cassette are schematically represented by walls 38 shown within the second inter-plate space 12. In the illustrated example, valve ports 34a,b may optionally include raised elements 40 (arranged circumferentially around the valve ports) to improve the sealing efficiency of the diaphragm. Such raised elements may be required to be present around only one of the valve ports in order to be effective. Thus, when the valve diaphragm is relaxed or pulled away from the fluid port of the valve, the fluid is allowed to flow from one fluid passage through its associated port into the fluid valve chamber and then out through the fluid port of a second fluid passage connected to its valve station. The selection of the cross-sectional area of ​​the fluid passage may depend on the desired fluid flow resistance and the desired hold-up volume or dead space occupied by the fluid passage in the cassette. The desired cross-sectional area of ​​the fluid passage determines the depth of the fluid passage (or the height of the passage wall) that occupies the second inter-plate space 22 between the intermediate plate 12 and the second outer plate 16 of the cassette. The fluid passage and working passage may be formed from the intermediate plate or individual outer plates, or independently of the outer plate or intermediate plate.In a preferred configuration, the intermediate plate, along with the desired passage walls on both sides of the intermediate plate, is formed by molding, 3D printing, or otherwise casting, thereby simplifying the structure of the outer plate. The outer plate 14 may include the roof or diaphragm limiting wall of the working chamber 26, and the outer plate 16 may include the roof or liquid passage within the cassette. In this way, the inter-plate space between the intermediate plate and the outer plate can be further reduced.

[0022] Accordingly, as shown in Figure 1A, in a preferred embodiment, the thickness T of the pump or valve cassette 10 may be defined by adding the depth E of the range of motion of the diaphragm 18 and the depth L of the liquid passage formed by the second inter-plate space 22 provided on the cassette to the nominal thickness P of the intermediate plate and the two outer plates. To maximize the efficiency of positioning and distributing valve and pump stations on the intermediate plate 12, it may be advantageous to arrange several working passages and working chambers on both sides of a single intermediate plate 12. In this case, the thickness T of the cassette is determined by the depth of the range of motion of the largest diaphragm on each side of the intermediate plate. For example, if the depth E of the range of motion of the pump diaphragm is the same on each side of the intermediate plate 12, the thickness T of the cassette will be equal to (2xE)+(3xP).

[0023] Figures 4A and 4B show an alternative embodiment of the diaphragm pump in the pump cassette 50. In this embodiment, the fluid port of the pump chamber is replaced by a wide opening 42 through which the diaphragm 44 can pass as it moves from the filled position (Figure 4A) to the discharge position (Figure 4B). Thus, the overall thickness T' of this cassette is determined by adding the thickness P of the two outer plates 46, 48 to the total range of motion distance or length E' of the diaphragm 44. The pump diaphragm 44 substantially utilizes the overall thickness of the cassette 50 to substantially increase the stroke volume of the pump. In this embodiment, the pumping chamber 52 is formed by the liquid side of the diaphragm 44 and a circumferential seal wall 54 covered by the second outer plate 48. Although liquid inlet / outlet pump ports 56, 58 are shown in this embodiment, other embodiments may include only a single port that functions as both an inlet and an outlet, or a plurality of ports whose inlet or outlet function is determined by a downstream valve in the liquid passage associated with each pump port. In this configuration, the stroke volume generated by the diaphragm is effectively doubled when there is no intermediate plate, thus minimizing the overall thickness of the cassette. This allows for a substantial reduction in the distance between plates for any desired pump stroke volume.

[0024] Figures 5A and 5B show additional mechanisms that may be optionally included in the pump or valve cassette. In this case, the diaphragms 60, 62 are shown to be fixed to the intermediate plate 12 by a diaphragm retainer or retaining wall 68 (see also retainer 100 in Figure 8). In other embodiments, the individual peripheral beads 64, 66 of the diaphragms 60, 62 can be fixed to the intermediate plate 12 by adhesive, by heat welding, by overmolding a section of the intermediate plate to surround and clamp the beads, by applying a solid continuous ring in place relative to the diaphragm beads, or by many other methods that ensure the diaphragms are fixed to the intermediate plate and that a seal is formed between the diaphragm beads and the intermediate plate to separate the liquid chamber 28 from the working chamber 26. In the illustrated example, the retainer or retaining wall 68, 100 is installed inside the peripheral wall 30 of the working chamber 26. As shown in the cross-section, the illustrated portion of the retaining wall 68 displays two fenestrations, slots, windows, or holes 70 that allow the operating pressure (e.g., pneumatic pressure) to be transmitted to the operating side of the diaphragm 60. For most of its circumference, the retainer or retaining wall 68 extends uninterrupted from the inside of the first outer plate 14 or 46 to a position adjacent to the beads 64, 66 of the diaphragms 60, 62. If the beads are made of elastomer material, the retainer or retaining wall 68, 100 acts to partially compress the beads during cassette assembly when the first outer plate is mounted against the opposing intermediate plate. A tight fit helps ensure that the diaphragm is securely mounted and that an airtight / watertight seal is formed. In a preferred configuration, two or more fenestrations 70 (or holes) of the retaining wall can be distributed around the retaining wall 68, thereby allowing positive or negative operating pressure to be transmitted relatively simultaneously to multiple sections of the diaphragms 60, 62.

[0025] In some cases, it may be advantageous to ensure that there is a continuous rigid clamping structure around the entire circumference of the diaphragm bead or rim. In such cases, multiple holes in the retaining walls 68, 100 may be preferable to slots extending to the diaphragm bead. Alternatively, the same result can be achieved by combining a continuous rigid ring (e.g., a metal or plastic washer) (not shown) applied to the diaphragm bead with the slotted retaining walls 68, 100. Preferably, the outer end of the ring or washer abuts against the inside of the surrounding wall of the valve or pump station to compress only the bead portion of the diaphragm, while the inner end of the ring or washer avoids contact with the diaphragm as the washer moves from the diaphragm bead to the diaphragm body.

[0026] In the illustrated example, the diameter of the retainer or retaining wall 68, 100 is small enough to allow a gap 72 to exist between the retainer or retaining wall 68, 100 and the surrounding wall 30 of the working chamber 26. The gap 72 allows the working pressure of the fluid or air to be distributed to the individual perforations 70 of the retaining wall 68. The retainer or retaining wall 68, 100 may be a separate element assembled together with the other components of the cassette, or the retainer or retaining wall 68, 100 may be formed or co-molded together with either the intermediate plate 12 or the first outer plate 14 of the cassette.

[0027] Figures 5A and 5B also show that the inner wall of the actuation or first outer plate 14 or 46 may optionally include a curved buttress 74 or 76, which helps to match the curvature of the diaphragm 60, 62 to the inner wall of the actuation chamber 26 when the diaphragm 60, 62 is fully extended toward the first plate 14 or 46 on the actuation side. This may help reduce the stress on the more peripheral portion of the diaphragm 60, 62 when fully retracted into the actuation chamber 26. Similarly, as shown in Figure 5B, a curved buttress 78 may be positioned along the end wall of the liquid pumping chamber 52 (liquid or second outer plate 48) for similar reasons. In these examples, it is not necessary to increase the overall thickness of either the cassette 10 or 50 to shape the inner walls of the outer plates 14, 46, and 48. The buttresses 74, 76, and 78 may be separate inserts attached to the individual outer plates, or they may be formed and co-molded with the outer plates such that any additional thickness of the outer plates is formed to erode the space between the plates rather than extending beyond the outer surface of the outer plates. The outer plates may be molded to curve inward from the outside of the plates toward the working chamber or fluid chamber, without increasing the overall thickness of the cassette.

[0028] Figure 6 shows a rear perspective view of an exemplary cassette 80 including multiple valve stations 82 and an exemplary pump station 84. In one example, the cassette is configured to have a length of approximately 16 cm, a width of approximately 19 cm, and a thickness of approximately 1.5 cm. The first outer plate or actuation plate 86 is molded with a recess on its outer surface to provide a curved inner surface that conforms to the corresponding diaphragms in the valve stations 82 and pump 84. In this example, the nominal thickness of each of the first outer plate 86, the second outer plate or liquid-side plate 88, and the intermediate plate 90 is approximately 2 mm, but the overall thickness of the cassette is approximately 15 mm. The first inter-plate space 92 and the second inter-plate space 94 are each approximately 4.5 mm wide. In this example, the pump diaphragm has a range of motion approximately equal to the 4.5 mm wide first inter-plate space 92. The cassette actuation passage ports 96 are shown arranged within the first inter-plate space 92 of the cassette 80. Therefore, a diaphragm range of motion of approximately 4.5 mm can be achieved with a cassette having a width of approximately 10.5 mm plus the desired width of the second inter-plate space 94 for the liquid passage. In this case, the second inter-plate space 94 has the same width as the first inter-plate space 92, although in other embodiments, the second inter-plate space 94 may be smaller (depending on the desired flow characteristics for the liquid passage). In this example, the range of motion of the cassette diaphragm is approximately 30% of the overall cassette width. Figure 7 shows a front perspective view of the cassette of Figure 6, revealing the cassette liquid passage ports 98 arranged within the second inter-plate space 94 of the cassette 80.

[0029] Figure 8 shows an internal perspective view of the first outer plate 86 of the cassette 80. In this example, the diaphragm retainers or retaining walls 100, 102 are molded as a single integrated part inside the first outer plate 86 (in a dual-duty cassette, both the first and second outer plates may include retainers or retaining walls 100, 102, as both sides of the intermediate plate may be pump or valve operating sides). In this example, each diaphragm retainer 100, 102 has a number of perforations or holes 104 and optionally has top grooves 106 for evenly distributing the operating pressure across the entire diaphragm held against the intermediate plate 90. The curved inner wall 108 of the outer plate 86 in the valve and pump station is positioned to match the relevant diaphragm shape when the diaphragm fully expands into the operating chamber (where the retainers 102 are located). In some cases, optionally, the rib 109 may be incorporated into the molding of the outer plate 86, and the rib 109 may be configured to erode the mating operating passage of the opposing intermediate plate. The rib 109 may be configured to have a cross-sectional size and length to adjust the total volume of the associated operating passage to a predetermined volume (this helps to minimize the amount of pneumatic gas supplied (or compressed) and can improve the responsiveness of the associated diaphragm to operation by the pressure supply manifold).

[0030] The operating volume adjustment rib may be particularly advantageous in configurations where both sides of the intermediate plate are equipped with operating passages and / or fluid passages, or in configurations where the inter-plate space must accommodate a wider diaphragm range of motion. In such cases, the installation of the operating volume adjustment rib can reduce the transmission volume of the operating passage and improve the performance of the cassette. Furthermore, when synchronous valve operation is desired, it may be advantageous to match the operating passage transmission volume among multiple sets of valves whose distance from the cassette's operating port varies. Thus, the operation of the cassette valve can be finely tuned using an appropriately sized volume adjustment rib.

[0031] Figure 9 shows a perspective view of the operating side of the intermediate plate 90 of the cassette 80. In this example, the operating passages 110, the surrounding walls 112 of the valve and pump stations, and the cassette operating ports 96 are formed or molded as part of the intermediate plate 90. In this example, most of the diaphragm valves or pump stations are supplied by separate operating passages 110 that extend from dedicated cassette operating ports 96. The fluid passages or operating passages of the cassette can be individually formed conduits, or each passage may include two walls spanning the interplate space, fused to and extending between the intermediate plate and either the first or second outer plate. In some cases, it is desirable to actuate two or more valve stations at once, in which case a single operating passage path 114 can supply two or more valve stations, as shown in valve stations 116, 118. Each valve station is surrounded by surrounding walls 112 that seal the station when the adjacent first outer plate 86 is welded to the intermediate plate 90.

[0032] The cassette plate can be formed from a moldable plastic material such as polysulfone that hardens to a rigid or rigid consistency (e.g., by injection molding). Other materials such as plastics or metals can also be used. Novel technologies such as 3D printing, as well as other molding methods, can be used to form the intermediate and outer plates. The outer plate can be bonded to the intermediate plate using adhesive or by localized heating by ultrasonic or mechanical vibration. Preferably, the outer plate can be transparent, translucent, or allow the transmission of laser wavelengths to enable laser welding of the outer plate to the opaque intermediate plate. The welding seals the valve and pump areas of the outer plate to the surrounding walls and passages of the individual valve and pump stations of the intermediate plate.

[0033] Each peripheral wall 112 forms part of the working chamber of an individual valve or pump station, and each peripheral wall 112 communicates with the working passage 110 via a working chamber port 120 within the peripheral wall 112. In this example, the pump station 84 has two pump ports 24a, 24b that connect a liquid passage on the opposite side (second side) of the intermediate plate to the first side of the intermediate plate shown in the figure. One of these functions as the inlet to the pump chamber and the other as the outlet to the pump chamber. In other embodiments, the pump area may have a single pump port or multiple pump ports. The multiple valve stations in this example each have two ports that connect two separate liquid passages on the second side of the intermediate plate to the valve station on the first side of the intermediate plate shown in the figure. Also in this example, one of the valve ports 34a has a raised peripheral lip 40 to improve the seal of the valve diaphragm to the valve port when positive pressure is applied to the diaphragm.

[0034] Figure 10 shows an enlarged view of the intermediate plate 90 in Figure 9. In this case, it is shown that the pump diaphragm 122 and valve diaphragm 124 are installed in individual pump stations and valve stations. The diaphragms are held in place and sealed against the intermediate plate 90 by corresponding retaining walls or cages 100, 102 shown in Figure 8. Note that the retaining walls or cages 100, 102 are (loosely) fitted within the circumference of the surrounding wall or chamber wall 112 of the individual valve station or pump station. The difference in diameter between the surrounding wall and the retaining wall is sufficient to allow a gap 72 (see Figure 5A) to exist between the two, enabling the working fluid or gas pressure to be evenly distributed around the relevant diaphragm.

[0035] Figure 11 shows a second side view of the intermediate plate 90 of the cassette 80. In this example, the liquid passage 126 is molded as part of the intermediate plate 90. In the case of the pump station 84, each of the two ports 24a, 24b is associated with separate liquid passages 128, 130, so that one port functions as the inlet port of the pump chamber and the other as the outlet port of the pump chamber. Whether a particular port functions as an inlet or outlet can be determined by which downstream valve is activated or closed.

[0036] Figure 12 shows a modified cassette 132 including additional optional mechanisms (which may be individually included in or excluded from any cassette design). In this case, the cassette incorporates actuation ports, actuation passages, and actuation chambers on both sides of the intermediate plate 134. Each of the first inter-plate space 136 and the second inter-plate space 138 includes both actuation passages and fluid passages, as well as actuation ports and fluid cassette ports. In this figure, two rows of actuation ports 140, 142 can be seen on the end or narrow side of the cassette, allowing that end of the cassette to be plugged into a connector or interface communicating with a pressure distribution manifold. In this embodiment, the overall thickness T2 of the cassette, which is the thickness of each of the intermediate plate 134, the first outer plate 144, and the second outer plate 146 plus the width of the first inter-plate space 136 and the second inter-plate space 138, allows a pump diaphragm or valve diaphragm to be mounted on the first or second side of the intermediate plate, or both. This potentially increases the number of valve or pump stations that can be installed in a cassette having a specific wide side dimension. In this embodiment, the overall thickness T2 of the cassette can be minimized while maximizing the density of pump or valve stations that can be included in the cassette 132, and the range of motion of the housed diaphragm constitutes a substantial portion of the overall thickness of the cassette. For example, in a cassette with such a “double-duty” intermediate plate (allowing working passages and chambers on both sides of the intermediate plate), the nominal plate thickness is 2 mm, and combined with a 5 mm inter-plate space, the overall thickness of the cassette becomes 16 mm to accommodate a 5 mm range of motion of the diaphragm, with approximately two-thirds of that constituting the desired range of motion of the diaphragm.

[0037] Figures 12 and 13 show an intermediate plate 150 of a dual-duty cassette, in which each of the first side 152 and second side 154 of the intermediate plate includes both working passages and liquid handling passages, incorporating working ports, working passages, working chambers, and liquid passages on each side of the intermediate plate. Although multiple valve stations 156 are shown in this example, an onboard pump station may also be included in other embodiments. In this regard, the cassette is similar to the cassette 132 in Figure 12.

[0038] Optionally, the intermediate plate 150 is additionally designed for use in cassette assemblies incorporating outboard pump pods or liquid mixing pods, because the volume requirements of the outboard pump pods or liquid mixing pods prevent them from being included as onboard pump stations or mixing chamber stations on separate cassettes. If a larger stroke volume is required, two or more cassettes can be arranged so that liquid lines or working lines are connected to extension conduits 158, 160 perpendicular to the cassette surfaces, which are connectable to external pods located between the two cassettes. The conduits (e.g., formed or molded together with the intermediate plate) originate from the cassette intermediate plate and penetrate either the first or second outer plate, providing direct connection to an external self-contained diaphragm pump, self-contained mixing chamber, or self-contained balancing chamber. If the conduits are rigid, they can also function as structural members assisting in holding the cassette assemblies together. The vertical conduit may be used as a liquid port for connecting to a fluid source or destination located outside the cassette. In this case, the end of the conduit may be configured to connect to a flexible or malleable tube. In this type of cassette, the cassette actuation ports and the initial portion of the actuation passages can remain entirely within the interplate space of the cassette until the fluid line or actuation line leaves the cassette and reaches the point where it must connect to the associated pod pump, balancing chamber pod, or mixing chamber. In this configuration, the cassette assembly is substantially improved over conventionally disclosed cassette assemblies because the cassette actuation ports are more efficiently arranged. Since all actuation ports are located along the ends of the cassette, the cassette can be plugged directly into the associated pressure supply manifold or rigid receptacle array without the need for flexible tube connections or separate connectors.

[0039] The cassette intermediate plate 150 in Figures 12 and 13 also shows that the working passages and fluid passages can be routed from a first side of the intermediate plate to a second opposite side in order to increase the number of valve stations or pump stations that can be incorporated into a cassette of a particular size. Routing of working or fluid passages may be difficult due to the presence of other passages, pump stations, or valve stations that obstruct a direct route from the cassette port to the desired valve station or pump station. In such cases, the working or fluid passages can be redirected to the first / second side of the intermediate plate, allowing the passages to bypass obstructing structures on the second / first side of the intermediate plate. The bypass passages may simply penetrate to the opposite side of a single intermediate plate, or they may penetrate the intermediate plate to bypass the obstructing structure and then return to the starting side of the intermediate plate to reach the desired pump station or valve station. Figure 14 shows the second side 154 of the cassette intermediate plate 150. The actuation port 162, configured to supply valve station 164, lacks an uninterrupted path to the valve station due to the presence of the extension conduit 168. The actuation passage 170a connected to the cassette actuation port 162 terminates at the actuation passage port 172, which penetrates the intermediate plate 150. As shown in Figure 13, the actuation passage 170b on the first side surface 152 of the intermediate plate 150 can connect actuation passage 170a to actuation passage 170c via actuation passage port 174, completing the path of the actuation passage from the cassette actuation port 162 to valve station 164.

[0040] Whether or not the cassette includes working passages and working chambers, as well as fluid passages, on both sides of the intermediate plate (i.e., a dual-duty intermediate plate), the cassette can be arranged to have fluid cassette ports located on the narrow side or end of the cassette, and as a result, multiple or banks of such cassettes can be stacked together to form a compact cassette group. Figure 15 is a rear perspective view of a cassette group 176 consisting of multiple individual cassettes 178a-d stacked from wide side to wide side. Each cassette 178a-d has one or more cassette working ports 180 located on the narrow side of the cassette in a first inter-plate space 182a-d, the working ports facing the same direction so that each cassette in the cassette group can be plugged into the individual corresponding connector ports or receptacle ports of a receptacle assembly, the connector ports or receptacle ports are located adjacent to each other and are connected to, mounted on or attached to a pressure distribution manifold.

[0041] The cassettes in a cassette group can be arranged to be in contact with each other, regardless of whether they are joined or bonded to one another. Alternatively, they can be arranged adjacent to each other with some play or spacing, so that each cassette in the group can be individually inserted into or removed from its corresponding receptacle assembly without interfering with adjacent cassettes. This allows individual cassettes to be placed on rails or tracks to properly align the actuation ports to individual connectors or receptacles, making insertion and removal easier. Cassette receptacle assemblies can be arranged adjacent to each other to provide a spatially compact cassette group. Optionally, cassette receptacle assemblies can be housed in a single housing, which provides alignment and insertion / removal tracks for individual cassettes. Alternatively, each cassette receptacle assembly may be housed in a separate housing for the same purpose. In settings that provide separate fluid circulation to the array in question, this configuration allows a single cassette to be swapped with cassettes having different mechanisms (in terms of the number and distribution of pump and valve stations, and fluid flow paths). Therefore, as the fluid circulation requirements for individual targets change, the configuration of the cassette group allows for convenient and rapid adaptation of the cassettes according to the needs of the relevant target. Furthermore, adjacent cassettes in the cassette group can be connected to each other via their individual liquid ports, for example, by jumper lines. In this way, complex liquid mixing procedures can be performed when it is necessary to provide a target with a solution containing specific components at a specific concentration. Thus, if necessary, one or more cassettes in the cassette group can be dedicated to a single target.

[0042] Figure 16 is a front perspective view of the cassette group 176 of Figure 15. In this example, for illustrative purposes, the cassette liquid ports 184 are located on the narrow side of each cassette 178a-d opposite to the actuation port 180. The actuation ports are preferably located at the same corresponding end of the cassette (so that the pressure distribution manifold can be positioned behind the cassette group), but the liquid ports of individual cassettes do not all need to be located along the same end of the cassette. In this embodiment, the cassette liquid ports 184 are located within the second interplate spaces 186a-d of the individual cassettes 178a-d. Thus, the cassette group 176 can be oriented outward from one or more receptacle assemblies (not shown) connected to, mounted on, or attached to a pressure distribution manifold. Since each cassette 178a-d can provide liquid circulation to individual objects, the number of individual cassettes in the group can be matched to the number of objects requiring liquid circulation. For example, multiple biological cell stations, tissues, or organs arranged for growth, experimentation, or testing can be supplied with circulating fluids, drugs, nutrients, or other chemicals by multiple cassettes within a cassette group, each cassette potentially supplying each cell station, tissue station, or organ station with a liquid solution having a similar or different composition. A cassette group, such as cassette group 176, can also be configured to function as a solution mixing station, where the liquid output of one cassette in the group provides the liquid input to adjacent cassettes within the group, enabling complex solution mixing protocols. Thus, two or more cassettes can be reconfigured to supply a single subject.

[0043] Figure 17A shows a rear perspective view of cassette group 186 incorporating dual-duty intermediate plate cassettes 188a-d, and Figure 17B shows a front perspective view. In other embodiments, the cassette group may incorporate one, two, or three or more dual-duty intermediate plate cassettes within one or more single-duty intermediate plate cassettes. In this example, the operating ports 190 of a typical second inter-plate space 182a-d and the liquid ports 192 of a typical first inter-plate space 186a-d are shown. Depending on the number and size of individual pump and valve stations within cassettes 188a-d, the use of dual-duty intermediate plate cassettes may allow for a higher density of multi-purpose valve and pump stations to be arranged in a relatively limited space.

[0044] In some applications, the stroke volume of the pump or other type of chamber, or the volume of the liquid chamber, exceeds the volume that the onboard pump or chamber can accommodate. In this case, an outboard pump or chamber pod is used and positioned between two cassettes. Liquid lines and / or actuarial lines originate from opposing faces of the two cassettes to supply the outboard pump or chamber, allowing the liquid to flow, for example, from the first cassette to the outboard pod and then to the second cassette, with each cassette housing an upstream or downstream valve station for controlling the liquid flow. Alternatively, the outboard pump actuarial lines may originate from the face of the first cassette, and the liquid inlet and outlet lines may originate from the opposing second cassette. This type of cassette assembly could also have liquid lines directly connected from the face of one cassette to the face of the opposing cassette. In conventional embodiments, as shown in Figure 18, the opposing surfaces of cassettes 194, 196, and 198 included a liquid port 204 and liquid lines 206 and actuation lines 208 to an outboard pump 210 or chamber 212, as well as an actuation port 200 for an onboard pump station and an actuation port 202 for a valve station. This configuration resulted in numerous flexible tube connections for both the liquid and actuation lines being inserted into the inner surface of the cassette, creating challenges in terms of manufacturing, assembly, and maintenance.

[0045] Figure 19 shows a conventional cassette assembly in which a pneumatic actuation line 214 extended from an actuation port 216 on the cassette surface 218 to block-type connectors 220a, b for subsequent connection to a pressure distribution manifold used to operate the cassette assembly. This was in addition to a fluid line 222 extending from a fluid port 224 on the individual cassettes. This type of cassette assembly has been substantially improved by incorporating the cassette design of the present disclosure.

[0046] Dialysis Cassette Assembly Figure 20 shows an example of a cassette assembly 226 that performs substantially the same fluid handling functions as the conventional cassette assemblies in Figures 17A, 17B, and 18, and helps illustrate how the cassettes of this disclosure substantially improve the structure, assembly, and maintenance of such cassette assemblies. In this example, the illustrated cassette assembly 226 is used to mix, process, and move dialysate within a portable hemodialysis machine. However, the use of this type of cassette or cassette assembly (i.e., a cassette having end-mounted operating ports with operating passages extending between plates and parallel to the cassette surface) is not limited to hemodialysis systems. As shown in Figure 20, three cassettes 228, 230, and 232 are coupled together by fluid handling pods 234 and 236. These inter-cassette pods may include a self-contained diaphragm pump having both operating and fluid conduits, or other fluid transport chambers 236 having only fluid conduits. Examples of other types of liquid transport pods include a fluid mixing chamber or fluid balancing pod in which a flow through a first fluid line is balanced by a flow through a second fluid line via a pod having a first variable volume separated from a second variable volume by a flexible diaphragm. Each fluid handling pod 234, 236 is fluidically connected to one or both of its adjacent cassettes by either a flexible or rigid conduit. A rigid liquid conduit 238 may be preferred because it can provide structural support for the cassette assembly. In the case of a diaphragm pump pod 234, both the liquid transport conduit and the actuation conduit may extend to one or both of its adjacent cassettes. The conduit 238 penetrates the face of the adjacent cassette to reach a fluid passage or actuation passage located in the first or second interplate space of that cassette. Generally, the actuation passage driving an inter-cassette pump pod proceeds without interruption from the cassette actuation port to the actuation chamber of the pump pod. The fluid passage of either the inter-cassette pump pod or another type of fluid handling pod connects to the corresponding inter-plate fluid passage of one or both adjacent cassettes via one or more diaphragm valves located within the cassette.The operating passages for these diaphragm valves, the operating passages for the pump pods, and any other operating passages within the cassette traverse the first or second interplate space of each cassette to the first end of each cassette and terminate at the cassette's operating port 240. In the cassette assembly, each cassette 228, 230, 232 has an operating port 240 located on the narrow side or end of each cassette, and is configured to all face the same direction so that the operating ports of the cassette assembly occupy one side of the cassette assembly. This allows the cassette assembly 226 to be inserted into or removed from one or more receptacle assemblies in a single operation. This configuration eliminates the need for flexible tubing to connect the cassette operating ports to the corresponding manifold output ports. In the example illustrated in Figure 20, cassette 228 is optionally configured as a single-duty intermediate plate cassette (all operating ports are located in either the first or second interplate space). In the same example, cassettes 230 and 232 are optionally configured as dual-duty intermediate plate cassettes, with several operating ports located in the inter-plate space on both sides of cassette intermediate plates 242 and 244. Other configurations are, of course, possible depending on the fluid handling tasks required for similarly configured cassette assemblies.

[0047] Figure 21 shows a partially exploded view of an exemplary cassette assembly 226 illustrated in Figure 20. The assembled cassettes 228, 230, and 232 are held within the frame assembly together with the inserted pump 234 or other liquid transport chamber 236, ensuring proper alignment of the cassette ports during installation and operation. Conventionally disclosed cassette assemblies could rely on rigid conduits (e.g., conduit 238) and several retaining bars or springs to hold the assembly together (see Figure 18), but did not require precisely aligned operating ports for direct insertion into the manifold assembly. In the cassette assemblies disclosed herein, carrier frames 505 and / or 507 can eliminate this concern by compactly securing the cassette assembly 226 and holding the cassette assembly 226 in the required configuration or alignment. Exemplary embodiments in Figures 20 and 21 show a first carrier frame 505 and a second carrier frame 507 that can engage with the cassette assembly 226 from opposing directions. Some embodiments may provide a similar carrier frame for securing the cassette assembly 226 from adjacent sides. Other embodiments may also provide a monolithic carrier frame for securing the cassette from two or more pairs of opposing sides.

[0048] The carrier frames 505 and 507 may further include plate rails that can slide across the corresponding cassette plates of cassettes 228, 230, and 232 to engage with the cassette assembly 226. By connecting the frame components to each other and securing the enclosed cassette plates to the rails, it is no longer necessary to puncture or drill holes in any of the three cassette plates to secure them to the frame. The rail configuration and the absence of screws, nuts, or clips passing through the cassette plates can reduce the possibility of damaging the cassette assembly and interfering with any pneumatic connections or pathways within it. For example, the first carrier plate 505 may include a first set of plate rails 505A, 505B, and 505C, and the second carrier plate 507 may include a second set of plate rails 507A, 507B, and 507C. The plate rails 505A, 505B, 505C, 507A, 507B, and 507C may have elongated slots capable of partially or completely receiving at least one end or a portion of an end of the corresponding cassette plate of the cassettes 228, 230, and 232. For example, referring to the first carrier frame 505, the plate rails 505A, 505B, and 505C can each receive the ends of the cassette plates of the cassettes 228, 230, and 232. In one embodiment, the rails may include capping features. For example, the rails 505A and 505C of the first frame 505 may include capping features 505F and 505G located at the ends of the individual rails. The plate rails 507A, 507B, and 507C can engage with the cassette assembly 226 by receiving the ends of the corresponding cassettes 228, 230, and 232. Furthermore, the walls of the plate rails 505A, 505B, 505C, 507A, 507B, and 507C may also optionally include notches 506 configured to accept and cradle the corresponding rigid fluid conduits 238 when the carrier frames 505, 507 engage with the cassette assembly 226.The plate rails 505A, 505C, 507A, and 507D may have closed and open ends. The open ends of the rails may be included to avoid interference with the nearby cassette port 240. It should be noted that the first and second carrier frames 505 and 507 can slide over individual cassette ends and engage with the cassette assembly 226, and may not require additional fastening devices for direct engagement with the cassettes 228, 230, and 232. Furthermore, fastening mechanisms that complement the rails, i.e., mechanisms such as, but not limited to, capping mechanisms 505F, 505G, and notches 506 and 508, can further enhance the engagement between the cassette assembly and the frame, thereby more evenly distributing any forces applied to the frame over the cassette assembly and potentially avoiding distortion or deformation of the cassette assembly 226. This configuration can help compactly mount and remove the cassette assembly 226 from the array of manifold receptacles of the hemodialysis machine 246 without creating difficulties with the cassette assembly that would lead to misalignment of the cassette ports.

[0049] Plate rails 505A, 505B, and 505C can be interconnected by upper bar 505D and lower bar 505E, which extend perpendicularly to the plate rails. The lower bar 505E interconnects plate rails 505A-505B and 505B-505C at the open ends of the rails and near the cassette port 240. The upper bar 505D interconnects plate rails 505A-505B and 505B-505C at the closed ends of the rails. Similarly, rails 507A, 507B, and 507C are interconnected by upper bar 507D and lower bar 507E, which extend perpendicularly to the plate rails. The lower bar 507E interconnects plate rails 507A-507B and 507B-507C at the open ends of the rails and near the cassette port 240. The upper bar 507D interconnects the plate rails 507A-507B and 507B-507C at the closed end of the rail.

[0050] If the frame is positioned to engage with the cassette assembly 226, at least one crossbar 511 can be positioned to connect the first and second carrier frames 505, 507. In this example, the crossbar 511 is positioned to pass longitudinally through the cassette assembly 226 and connects the first and second carrier frames 505, 507 at both ends of the crossbar. This configuration helps to stabilize the sides of the frames 505, 507 near the ports 240 of the cassettes 228, 230, 232. The crossbar 511 helps to prevent the frames 505, 507 from shifting position relative to the cassette assembly 226. The connection between the individual ends of the crossbar 511 and the corresponding carrier frames 505, 507 can be established by fastening mechanisms such as screws, bolts, adhesives, laser or ultrasonic welding, or other similar fastening mechanisms, but not limited to these. Optionally, the cassette assembly 226 may provide alternative or additional connecting elements between the first carrier frame 505 and the second carrier frame 507 to fasten them to each other, and the cassette assembly 226 may include, but is not limited to, clips similar to the clip 512 in Figure 18, threaded rods, or zip ties, or other elements that restrict the frames 505, 507 to the extent that they can shift relative to each other.

[0051] Figures 20 and 21 further illustrate a first support plate 513 and a second support plate 515. The first support plate 513 can be positioned to interconnect the first and second carrier frames 505, 507 that engage with the cassette assembly 226. In this example, the first support plate 513 is positioned on the side of the cassette assembly 226 perpendicular to the side on which the first and second carrier frames 505, 507 are positioned. Furthermore, the first support plate 513 is positioned on the carrier frame opposite to the cassette port 240. The first support plate 513 may further include flanges 513A and 513B at both ends. These flanges 513A, 513B can be configured to engage with the upper bars 505D, 507D of the first carrier frame 505 and the second carrier frame 507. The first support plate 513 can be mechanically fixed to the upper bars 505D, 507D with clips, screws, or the support plate 513 can be coupled to the upper bars 505D, 507D. Alternatively, the upper plate 513 and at least one of the frames 505, 507 can be molded together. The first support plate 513 can engage with the upper bars 505D, 507D when the carrier frame engages with the ends of the cassettes 228, 230, 232 of the cassette assembly 226. Thus, the first support plate 513 and the crossbar 511 can fix the first and second carrier frames 505, 507 to each other while engaged with the cassette assembly 226. The assembly, including the carrier frames 505, 507, the crossbar 511, and the first support plate, securely holds the cassette assembly 226 and helps to evenly distribute external mechanical forces across the components of the cassette assembly, preventing distortion of their relative positions.

[0052] The first support plate 513 can further provide an inner surface 513D (see Figures 22A and 22B) facing the cassette assembly 226 and an outer surface 513C facing away from the cassette assembly 226. During the installation of the cassette assembly 226, the outer surface 513C of the first support plate 513 can interact with a cassette loading device (not shown) as described below. The inner surface 513D and the outer surface 513C provide surfaces on which the cassette loading device can apply force to move the cassette assembly as a unit. The first support plate 513 can also provide an alignment mechanism for properly loading and positioning the cassette assembly 226 into the loading device.

[0053] Figure 21 also shows a second support plate 515 which can be optionally included to engage with one of the carrier frames 505, 507 in order to minimize frame twisting or bending. In this example, the second support plate 515 is attached to the second carrier frame 507 and to the frame via a connecting element 519. The connection can be achieved by having the connecting element 519 accept a corresponding connecting junction 520 provided on the second carrier frame 507. In another embodiment, the second carrier frame 507 may be integrated with a support plate such as the second support plate 515 as a single component, but is not limited to this. Deflection or twisting of the first carrier frame 505 can also be reduced by including a diagonal cross member 523. The cross member 523 may be integrated with the structure of the second carrier frame 505 or may be attached separately to the frame. Additional support elements similar to the support plates 513, 515 and support brackets 523 can be provided to complement the carrier frames 505, 507 and hold the required position of the cassette assembly 226.

[0054] Figures 22A and 22B show a perspective view of an exemplary first support plate 513. The flanges 513A and 513B can further provide engagement mechanisms such as elastic clips or grippers 514, but are not limited to these. The first support plate 513 may also include one or more clips 514 on the flangeless side. The clips 514 can be configured to engage with the ends of the carrier frames 505 and 507. For example, the clips 514 can be configured to engage with the upper bars 505D, 507D. Alignment elements such as one or more nubs 516 (Figure 21) may be included on the ends of the carrier frames 505, 507. The nubs 516 can serve as an alignment mechanism for slots 514B on the first support plate 513 to ensure proper alignment and connection between the first support plate 513 and the carrier frames 505, 507. In this embodiment, the first support plate 513 may include longitudinal and / or transverse reinforcing members 517 to reduce mechanically induced deformation of the first support plate 513.

[0055] Figure 23 shows a hemodialysis machine 246 configured to enclose a cassette assembly 226. The front panel 248 is configured to include a dialyzer recess and holder 250, a blood pump cassette receptacle assembly 252, and to hold a blood tubing set (not shown). The dialysate cassette assembly 226 is configured to be housed in an enclosure of the machine 246 behind the front panel 248.

[0056] Figure 24 shows the enclosure 254 of the apparatus 246 of Figure 23, with the front panel 248 and other components removed. The internal configuration of the enclosure or housing 254 allows the cassette assembly 226 to be placed on the internal shelf 256 of the enclosure 254. The interior of the enclosure 254 (e.g., below the shelf 256) is configured to hold other components such as a heater for the dialysate solution, tubing for various fluid flow paths, a dialysate reservoir or tank, and one or more devices for detecting the conductivity and temperature of the dialysate solution at various stages of mixing. Behind this enclosure 254 is a recess 258 configured to hold a pressure distribution manifold with electromechanical valves (in this case, a pneumatically operated manifold) and one or more electronic controllers, at least one of which is configured to control the electromechanical valves of the manifold. These components are located outside the enclosure 254 to help protect them from the high temperatures that may be used when sterilizing the fluid transport components of the hemodialysis machine 246. Figure 25 shows a rear perspective view of enclosure 254, highlighting a recess 258 located directly below shelf 256 of enclosure 254. Thus, the pressure distribution manifold can be positioned directly below cassette assembly 226, with the cassette assembly located inside enclosure 254 and the pressure distribution manifold located outside enclosure 254.

[0057] Loading and locking of the cassette assembly Figures 30 and 31 show the installation and retention of the cassette assembly 226 within the enclosure 254. In Figure 30, the cassette assembly 226 is raised directly above the three cassette receptacle assemblies, with the three arrays of cassette actuation ports 240 aligned with the individual receptacle ports on adapters 266, 268, and 270. The receptacle assemblies are configured to align the actuation port array of the cassette assembly 226 with the actuation outlets of the pressure distribution manifold located outside the enclosure, below the shelf 256. By lowering the cassette assembly 226, the cassette actuation ports 240 can be engaged with the individual adapters via press-fit connections. Seal of the individual actuation ports 240 can be achieved by using O-rings, or gaskets with elastomeric wiper seals, or other means commonly used when sealing press-fit connections. Next, the adapter can provide direct connections to the output ports of the pressure distribution manifold (Figures 32–37) located below the shelf 256 and outside the enclosure 254. Figure 30 further shows a cassette loading device 292 that can receive the cassette assembly 226 during installation and hold it in place. A handle 308 belonging to the loading device 292 can be operated to lock the cassette assembly in the enclosure 254. A detailed description of the operation of the device 292 and handle 308 for locking and holding the cassette assembly is provided below with reference to Figures 56–59. In one configuration, the loading assembly in Figure 30 can be in an open position showing an operating handle extending parallel to and away from the cassette assembly. Figure 31 shows the operating handle 308 tilted downward, indicating that the loading device is moved toward the receptacle assembly of the manifold, thereby pushing and securing the cassette assembly 226 into the corresponding adapter port, and thus the cassette assembly 226 is locked in the cassette receiving space.In this example, the loading device 292 may include, but is not limited to, one or more force-applying elements, such as bars, that can interact with the first support plate 513 (Figures 22A and 22B) and can be operated by the handle 308. Lowering the handle 308 can allow the force-applying elements to press against the first support plate 513. This force can be transmitted to the cassette assembly 226 via the cassette frames 505, 507, which press the cassette assembly 226 toward the adapters 266, 268, and 270. Figure 31 shows the cassette assembly 226 in an operational configuration, that is, the cassette assembly 226 is pressed so that the array of cassette operating ports 240 aligns with their individual adapters 266, 268, and 270. Note that the handle 308 in Figure 31 is shown in the closed position. Specifically, the cassette assembly 226 is locked inside the enclosure 254, and the handle is positioned so that it can be installed without interfering with the front panel of the hemodialysis machine.

[0058] The hemodialysis machine 246 of the embodiment shown in Figures 45 and 46 includes an enclosure 254 in which the footprint of the cassette assembly 226 extends forward of the shelf 256 and protrudes from the shelf 256. Therefore, as shown in Figure 45, a group of manifold interfaces or adapters 266, 268, and 270 are configured to extend forward of the shelf 256. The adapters 266, 268, and 270 provide the necessary mating between the operating port 240 of the cassette assembly 226 and the individual connectors or receptacle ports 272 located on the interfaces or adapters 266, 268, and 270. In this example, the adapters 266, 268, and 270 function as a receptacle assembly, providing an array of receptacle ports for mating with the cassette ports 240 arranged on each cassette 228, 230, and 232, respectively. Figure 46 shows a bottom perspective view of enclosure 254 with interfaces / adapters 266, 268, and 270 attached. This figure clearly shows the extent to which the adapters protrude from enclosure shelf 256 (and therefore from pressure supply manifold 260). Adapters 266, 268, and 270 serve to map cassette ports, which are arranged in an elongated direction along the ends of individual cassettes, to risers between adapters 266, 268, and 270 and the upper block 274 of the pressure distribution manifold 272 below them, or to a more spatially compact array of manifold ports located in upper blocks 276A-C.

[0059] pressure distribution manifold Figure 26 shows a schematic diagram of a pressure distribution manifold (or manifold assembly) of one embodiment. This manifold assembly is configured to selectively provide pneumatic pressure (positive, negative, or atmospheric pressure) to control pneumatically driven pumps and / or valves on two separate pump cassettes. In this improved embodiment, a first set of pneumatic outlets is configured for direct connection to a first pump cassette or cassette assembly (i.e., direct plug-in connection to the manifold assembly or to an adapter directly connected to the manifold assembly). In one embodiment, the direct connection interface is schematically shown as one or more risers or “upper blocks” 276A, 276B located above the manifold assembly 260. The upper blocks include a direct connection port 261 configured to connect directly to a first pump cassette (not shown), which may be located directly above the manifold assembly 260. The manifold or manifold assembly also includes a second set of pneumatic outlets configured to connect indirectly to a second pump cassette via flexible or malleable tubing. Figure 26 also shows an exemplary fitting 582 for indirect connection to a second pump cassette (not shown), the connection being configured for a flexible or malleable tube that travels a certain distance to the second pump cassette located away from the manifold assembly 260. In connection with the hemodialysis apparatus described herein, the dialysate cassette assembly may be configured to plug directly into the manifold assembly via port 261, and the blood pump cassette assembly (located further away from the front panel of the dialysis apparatus) may be configured for pneumatic connection to the manifold assembly via flexible or malleable tubes to a plurality of fittings (represented here by exemplary fitting 582).

[0060] Figure 26 also shows another improvement in the manifold assembly 260 that helps prevent or reduce the accumulation of particulate matter or liquid debris on the internal sealing surface of the electromechanical pneumatic control valve. The exemplary valve 267 is generally shown in a horizontal orientation. The internal valve seat or sealing surface is oriented so as not to have a horizontal surface where debris could accumulate. In the schematic diagrams of Figures 26 to 29, the lower or bottom manifold block 272 fits with the intermediate manifold block 274. The lower manifold block 272 has a "T" cross-sectional shape (crossing the long axis "Z" of the manifold assembly 260) including a horizontal portion 272A and a hanging portion 272B, with multiple valve mounting surfaces and openings located on the hanging portion 272B. The exemplary valve 267 is shown mounted on one such surface and above one such opening. A valve surface seal (not shown) is assumed to connect the valve body to the mounting surface of the hanging portion of the manifold. For convenience, the hanging portion 272B is shown to have a orientation perpendicular to the horizontal portion 272A. The hanging portion 272B may have a non-vertical orientation, such as being inclined upward such that the valve mounting surface and opening are oriented downward at an angle. This angled orientation also helps prevent the accumulation of liquid (e.g., liquid condensate) or waste on the valve component having a sealing surface (e.g., valve seat). In many (but not all) embodiments of the valve, the associated internal valve plunger or piston operates horizontally or nearly horizontally, as represented by the valve 267 schematically shown in Figures 26–29.

[0061] In the examples illustrated in Figures 26–29, the pressure source lines 263 are shown to be embedded within the lower or bottom manifold block 272. Depending on the piping method of the internal pneumatic passages within the manifold assembly 260, these pressure source lines may also be located within the intermediate block 274. In the schematic diagrams shown, each of the multiple valves 267 has an input line that receives an input line from one of the pressure source lines 263 and an output line that is ultimately connected to an output port of the manifold assembly (either a direct connection port 261 or an indirect connection port 582).

[0062] Figure 27 shows a schematic diagram of an embodiment of a manifold assembly 260 in which direct connection blocks 276A, 276B are projecting, cantilevered, or offset from the body of the manifold assembly. In this diagram, the long axis ("Z") of the manifold assembly can accommodate pump cassettes of any length in the long axis direction. However, if the pump cassette is configured to have an array of inlet ports that exceeds the front-to-rear ("X") dimension of the main manifold assembly, the direct connection blocks can be positioned to project from the manifold assembly in that direction. Port 261 is then connected to passages within blocks 276A, B to be routed to a more compact array of one-to-one mapped ports located on top of the intermediate block 274.

[0063] Figure 28 shows a schematic diagram of a manifold assembly 260 in one embodiment in which an array of pressure sensor supports 567 is located between direct connection blocks 276A and 276B. In this case, various pneumatic passages within the manifold assembly may have branching or in-line connections to the sensor supports 567A of the pressure sensor array 567. In most (but not all) cases, these passages connect to the output lines of pneumatic control valves and the output ports of the manifold assembly to which the valve output lines are connected. In one example, the array of pressure sensing ports may be located above the array and configured to mate with a printed circuit board (PCB) containing the corresponding array of pressure sensors. The pressure sensors on the PCB may be connected to a hemodialysis controller. The hemodialysis controller uses the pressure information to control the pneumatic control valves to supply a predetermined level and pattern of pressure to the pump or valve target in the connected pump cassette.

[0064] Figure 29 shows a schematic diagram of a manifold assembly 260 in one embodiment, including one or more manifold adapters or interface blocks 266, 268. In this example, upper blocks 276A, 276B function as risers, providing space between the directly connected pump cassette to be mounted and the body of the manifold assembly 260. The risers may include pneumatic passages that connect several valves on the manifold (such as valve 267) to the manifold adapters or interface blocks 266, 268, ultimately connecting to the associated pump cassette. The manifold adapters or interface blocks can be configured to spatially redistribute output ports 261a, which are arranged relatively closely together within the riser block or other blocks of the manifold, to output ports 261b, which are arranged at different intervals or in different distributions. In this way, the directly connected output ports of the manifold assembly can be spatially arranged or redistributed to match the corresponding input ports of the corresponding directly connected pump cassette. Accordingly, the manifold adapters 266, 268 include transfer ports on a first side facing the manifold 274 or its associated risers 276A, B, and these transfer ports are mapped to corresponding transfer ports 261b on the opposite second side facing the pump cassette assembly. Thus, a first array of manifold output ports having a first spatial port configuration can be directly mated to a second array of cassette input ports having a second spatial port configuration. The mapping between the corresponding transfer ports is achieved through the routing of internal passages within the manifold adapters 266, 268. In this case, the spatial array of output ports of the manifold or riser has a shorter length than the spatial array of transfer ports of the manifold adapter on the second side of the adapter. As a result, the manifold adapter cantilever outward from the front of the manifold. These mechanisms help to decouple the spatial and dimensional constraints of the pump cassette assembly from the spatial and dimensional constraints of the manifold assembly configured to drive the cassette(s) of the pump cassette assembly.In embodiments of this specification, the manifold assembly can be made as compact as permitted by valve constraints, passage constraints, and port constraints, while retaining the ability to interface with a pump cassette which may have substantially different spatial constraints or spatial array requirements for its operating ports.

[0065] Figures 32 and 33 show details of a pneumatically operated manifold in one embodiment of the pressure distribution module 260. The pressure distribution module 260 provides selectable pneumatic connections from multiple pressure sources to cassette assemblies that are plugged into receiving ports on the platform of manifold adapters 266, 268, and 270. The pressure distribution module 260 can further provide selectable pneumatic connections to remote cassettes via flexible or malleable pneumatic lines (not shown). The pneumatic connections are selectively controlled by digital or binary pneumatic valves 262, 265, and 267 mounted within or on the manifold block. One or more controllers control the state of the valves based on signals received from pressure sensors mounted on the upper block 276, and in the case of a hemodialysis machine, they selectively actuate the valves to provide programmed instructions for pumping blood, dialysate, and water in order to provide dialysis treatment to the patient.

[0066] The pressure distribution module 260 controls the operation of pneumatically driven diaphragm pumps and pneumatically driven fluid valves by selectively connecting to one or more pressure reservoirs via digital or binary electromechanical valves. The electromechanical valves may include two-way digital valves or three-way digital valves. Digital valves may have two positions. Two-way digital valves are either open or closed. Three-way digital valves connect a common port to either a first port or a second port. One or more controllers control the state of valves 262, 265, and 267, partly based on signals received by one or more controllers from the pressure sensor 565 (see Figure 34). The pressure reservoirs may include high-positive-pressure reservoirs, low-positive-pressure reservoirs, negative-pressure or vacuum reservoirs, and vents to the atmosphere.

[0067] The pressure distribution module 260 can be assembled from multiple manifold blocks. The pressure distribution manifold 260 in Figures 32 and 33 comprises a T-shaped manifold block 272, an intermediate manifold block 274, and an end manifold block 276. The pressure distribution manifold 260 further comprises a cartridge valve 265 mounted within the intermediate manifold block 274 and a surface-mount valve 267 mounted on the vertical leg of the T-shaped manifold block 272. The arrangement of the pressure reservoir port 263, the first set of valves 265, and the second set of valves 267 may be horizontal with respect to the surfaces 272F, 274F, and 276F (Figure 33) belonging to the manifold blocks 272, 274, and 276, respectively. This configuration helps avoid the accumulation of waste or liquid in the valves, which could impair valve function or shorten their maintenance-free life. The pressure sensor 565 (Figure 34) is mounted on port 567 on the upward-facing opposite surface of the end manifold block 276. Adapters 266, 268, and 270 provide ports 266P, 268P, and 270P for receiving port 240 of the cassette assembly 226.

[0068] The intermediate manifold block 274 and the T-shaped manifold block 272 may include internal supply lines for atmospheric pressure, low positive pressure, high positive pressure, and negative pressure. One or more of these internal supply lines extend along the entire length of the manifold blocks 272, 274. The ports for the internal supply lines are capped 264 or have ports 263 for flexible tubing connections to a pressure reservoir. Both end faces of the manifold blocks 272, 274 may include ports for connecting internal supply lines (not shown) to an external pressure reservoir.

[0069] Multiple diaphragm pumps and diaphragm valves can be grouped into a single cassette as shown in Figures 6 to 13. Multiple such cassettes can be joined together to form a cassette assembly 226 as shown in Figures 20 and 21. In this case, the assembly is arranged with the cassettes separated to accommodate the outboard pumps, and the mixing chamber or fluid balance chamber has a larger volume than can be accommodated in any one of the individual cassettes. The pressure distribution module 260 includes adapters 266, 268, and 270 that extend perpendicular to the long axes of the manifold blocks 272, 274, and 276. The adapters extend the interface area of ​​the pressure distribution module from the area occupied by the manifold blocks and risers to any area necessary to accept the ports 240 of the cassette assembly 226. The pneumatic layout and port distribution on and within adapters 270, 268, and 266 and their subcomponents (not shown) enable direct connection between cassette assembly 226 and manifold blocks 272, 274, and 276 using a one-to-one mapping of each port in the cassette assembly to the corresponding operating port in the manifold assembly.

[0070] An external pressure reservoir to which the pressure distribution module 260 may be connected may have a capacity maintained at a specified or predetermined pressure by a pump controlled by a system controller. In one embodiment, the high-pressure reservoir may be maintained at a pressure of approximately 1050 mmHg, and the positive-pressure reservoir may be maintained at a pressure of approximately 800 mmHg. The pressure actually supplied to various pneumatically operated pumps and valves may vary based on the pressure reservoirs ported by the two-way and three-way valves of the pressure distribution module 260. Furthermore, intermediate pressures may be supplied by a combination of rapid opening and closing of on / off valves. In general, high-pressure sources may be useful for acting diaphragm valves to ensure leak-free and reliable valve closure during the operation of the cassette assembly.

[0071] Figure 33 shows an exploded view of the pressure distribution manifold 226. Manifold blocks 272, 274, and 276 may further include intermediate element connecting mechanisms between each of the manifold blocks 272, 274, and 276. These intermediate elements and connecting mechanisms can help assemble the three manifold blocks to establish pneumatic connections between the individual manifold blocks 272, 274, and 276. The first set of intermediate components may include, for example, a first plate 550, a first gasket 552, and a second gasket 554 that can be used between a T-shaped manifold block 272 and an intermediate manifold block 274, and the second set of intermediate components may include a second gasket plate 555, a third gasket 556, and a fourth gasket 558 positioned between the intermediate manifold block 274 and the end manifold block 276. Two manifold blocks 272, 274 can be clamped together with a gasketed intermediate plate 550 between them. The intermediate plate 550 may be called a backing plate because it provides a rigid surface that forces a gasket to seal over a plurality of passages that may be provided on the end manifold block 276, the T-shaped manifold block 272, and the intermediate manifold block 274. Each manifold block 276, 274, 272 may have at least one surface 276G, 274F, 272F (see Figures 33, 35, and 36) having passages and various ports that engage with ported plates and gaskets (plates 550, 555 and gaskets 552, 554, 556, 558, etc.). Each passage may be configured as a groove including a solid bottom and two side walls having an open top. The passages may be cut into one face 276F, 274F, 272F of the manifold block, or formed by walls extending above the surfaces of the manifold block faces 276F, 274F, 274G, and 272F. As shown in Figure 33, the open tops of the passages may be sealed by clamping gaskets 554, 552, 556, 558, which are backed by flat intermediate plates 550, 555 that are rigid to the passages.In one example, the intermediate plate 550 is a backing plate that presses gasket 552 against all passages on surface 272F and biases gasket 554 against passages on surface 274G. Note that surface 274G is on the opposite side of surface 274F in Figure 33. The manifold block and gaskets may include a mechanism to ensure a substantially uniform distribution of pressure to the gaskets. The intermediate plate 550 provides a substantially smooth and rigid backing to the gaskets, and as a result, multiple manifold blocks are assembled or sandwiched within the multi-part pneumatic manifold 260. The passages are linked to pressure sources, valves, sensors, and outlet ports located on the other surfaces of the block. Manifold blocks 276, 274, and 272 can seal multiple passages on the respective passage-formed surfaces 272F, 274F, 274G, and 276G of manifold blocks 272, 274, and 276 by sandwiching gaskets 552, 554, 556, and 558 and intermediate plates 550, 555 between them with mechanical fasteners 570. This sandwich structure allows for the compact assembly of multiple manifold blocks, each with multiple sets of passages on one side of each block 272, 274, and 276.

[0072] The connection points of the T-shaped manifold block 272 can be configured to accept threads that extend through other components that assemble the pressure distribution manifold 260 as a unit. In this example, matching connection points 572 can be located on the first gasket plate 550, connection point 573 on the intermediate manifold block 274, and connection point 573 on the third and fourth gaskets 556, 558. The first set of valves 265 can operate on the pneumatic paths within the manifold blocks 272, 274, and 276, and / or on the pneumatic paths connecting the manifold blocks 272, 274, and 276.

[0073] Figures 32 and 33 show an embodiment including multiple cartridge valves 265 and connections to a pressure reservoir 263. The cartridge valves are inserted into manifold ports. Corresponding cavities (not shown) are formed to house seals on the outside of the cartridge valves 265. The machined cavities may have a set of dimensions specified by the valve manufacturer to ensure sealing and proper function of the cartridge valves 265. In other embodiments, the number may vary, but in this particular embodiment, approximately 48 cartridge valves 265 are mounted on the side of an intermediate manifold block 274. This side of the intermediate manifold block 274 is perpendicular to the surface 274F in which the passages are formed. In some embodiments, the cartridge valves are three-way valves, such as the Lee LHDA plug-in valves available from Lee Company in Westbrook, Connecticut, USA. The number of electromechanical valves is determined by the number of individual diaphragm pumps and valves actuated by the direct-connection cassette assembly and the remote-connection cassette assembly (if required), and the linear arrangement of the electromechanical valves will extend the length of the manifold assembly.

[0074] Referring here to Figure 34, the pressure distribution manifold can function as a pneumatic actuator for components other than the cassette assembly 226. For example, the pressure distribution manifold 260 can also pneumatically communicate with other pneumatically driven valves, diaphragm pumps, pneumatic cylinders, and remote cassettes including diaphragm valves and diaphragm pumps. In one example, the pressure distribution module 260 controls the position of the occluder 251 in Figure 23, which includes a pinch valve for shutting off the blood line and is driven by a pneumatic cylinder. In another example, the pressure distribution module 260 can be positioned to pneumatically communicate with the dialysate tank to perform volume measurement of the tank using pressure information. Furthermore, the pressure distribution module 260 may be configured to control the pump operation of a blood pump cassette (not shown) attached to the blood pump cassette receptacle assembly 252 in Figure 23. Referring here to Figure 34, the port 582 shown on the T-shaped manifold block 272 can be connected directly to one or more blood pump cassettes or via flexible or malleable tubing to establish the necessary pneumatic connections. The port 582 includes fittings that connect to pneumatic tubing and may be individually detachable from the T-shaped manifold 272. A pneumatic line, one end of which is connected to the port 582, may have the other end connected to a connector on the surface of the dialysis machine wall 255 (Figure 24). A second connector within the housing can be connected using flexible tubing to, for example, a dialysate tank, a pneumatically operated tubing occluder, and / or a blood pump cassette receptacle assembly 252.

[0075] In this embodiment, the cartridge valve 265 and the surface-mount valve 267 control the air pressure supplied to the occluder, blood pump cassette, and other pneumatically driven components within the hemodialysis machine 246. The pressure distribution module 260 can be mounted on the rear wall of the enclosure 254, and mounting mechanisms such as standoffs 580 can be provided to position the adapters 266, 268, and 270 relative to the enclosure 254.

[0076] Continuing to refer to Figures 34 and 35, the valve 267 positioned on the T-shaped manifold block 272 is an electromechanical valve that seals to a flat surface or a surface machined to accept the valve surface. In some embodiments, the surface-mounted valve 267 may be a proportional valve or a continuously variable valve (also called a “variable valve”). In other embodiments, the surface-mounted valve 267 is a binary two-way valve or a three-way valve. In some examples, the surface 272F is nearly horizontal, so that the legs of the T-shaped cross-section of the manifold 272 are nearly vertical. In a preferred configuration, the valve mounting surface of the leg is vertical or slightly inclined upward, so that the port on the valve 267 is horizontal or inclined downward to avoid the accumulation of waste or liquid. To prevent leakage of fluid or air, a sealing mechanism such as an O-ring and / or other element may be provided on the valve. The valve can be any digital two-way or three-way valve suitable for surface mounting, such as the Model 11-15-3-BV-12-P-0-0 from Parker Hannifin Corporation in Hollis, New Hampshire, USA.

[0077] Referring here to Figure 34, the pneumatic flow on the pressure distribution manifold 226 can be monitored via one or more pressure sensors, which can be mounted on a sensor board (e.g., a PCB). In this example, the sensor board 560 can be located on the surface 567 of the upper manifold block 276 in the space between risers 276A-C. A pressure sensor 565 can be mounted directly to the surface 276F of the first end manifold block 276. The pressure sensor 565 may be an integrated circuit soldered to the printed circuit board (PCB) 560. As shown in Figure 34, the printed circuit board 560 including one or more pressure sensors 565 may be mounted on the upper surface 276F of the second end manifold block 276, parallel to the surface where the passages are formed, by gaskets for pneumatically isolating each sensor and a plate (not shown) for holding the PCB 560 in place and sufficiently compressing the gaskets to seal each pressure sensor from the atmosphere. The sensor board 560 can be coupled to the surface 567 of the end manifold block via fixing components such as screws, nut-bolt pairs, rivets, adhesives, or a combination of such fastening mechanisms. An example of a pressure sensor 565 is available from Freescale Semiconductor, Inc. (part number MPXH6250A) in Tempe, Arizona, USA. A PCB containing multiple pressure sensors 565 can be mounted as a unit to the end manifold block 276. The pressure sensing surface of each pressure sensor 565 may be fluidically connected to a desired pressure source, such as a reference volume, or more remotely to the working chamber of a diaphragm pump or a dialysate reservoir tank. In some cases, the sensors are positioned to monitor the fluid pressure of various diaphragm pumps in a fluid handling cassette. The end manifold block 276 includes risers 276A, 276B, and 276C that can interface with individual adapters 270, 268, and 266. The manifold assembly is configured to prevent the sensor board 560 from engaging with the riser and the corresponding adapter.The riser also provides separation between the fluid processing cassette assembly and the temperature sensing sensor board 560, thereby allowing the placement of an insulating material 269A between the two (see, for example, Figure 48).

[0078] Figures 36 and 37 show a second manifold block 276 having a surface 276F and a base surface 276G. The base surface 276G can be configured to mate with one or more intermediate components such as a gasket, a gasket plate, and / or other manifold blocks. As shown, the base surface 276 can include a plurality of pneumatic passages 574 sealed by a gasket 558 (Figure 33). In some examples, the passages 574 can connect pressure ports 567 on surface 276F to holes 261A, 261B, and 261C in risers. In other examples, the passages 574 can connect pneumatic passages or holes to either pressure ports 567 or holes 261A, 261B, and 261C via a gasket 558. Surface 276F can include risers 276A, 276B, and 276C, which can function as mounting surfaces for corresponding adapters 270, 268, and 266, respectively. The pneumatic ports 261A, 261B, and 261C on risers 276A, 276B, and 276C can interface with individual adapters 270, 268, and 266 to transmit pneumatics to the cassette assembly 226. Fixed connections between riser port 261 and adapters can be established via mechanical fixtures such as nut-bolt pairs, screw-type or set-screw-type or similar mechanisms. Mechanical assembly may also involve mating the block with intermediate components such as one or more gaskets 568 (Figure 32), gasket plates, and / or similar parts.

[0079] Pneumatic connection within the manifold The structure and function of the manifold 260 in Figure 32 can be further understood by examining the pneumatic source, conduits, valves, sensors, and outlet ports of the manifold 260. In the example illustrated in Figure 32, the manifold 260 has dozens of valves, sensors, and ports. The following sections describe three exemplary pathways, including a pressure source, valves, conduits, ports, and, in one example, a pressure sensor. The exemplary pathways help illustrate how the manifold elements in Figures 32 and 33 combine to provide a selectable fluid connection between the pressure source and the working chambers of the pneumatically driven valves and pumps, and to provide a fluid connection to the pressure sensor. The pressure sensor provides information to a controller that controls the valves in order to safely pump blood, dialysate, and water to provide treatment to a patient.

[0080] The schematic diagram of the pneumatic manifold in Figure 38 shows the pneumatic connection to the blood pump cassette (in this case, the blood pump cassette is located on the front panel of the dialysis unit and is therefore connected to the manifold using flexible tubing rather than directional connections). The pneumatic circuit in Figure 38 selectively connects the blood working chamber, heparin pump, and associated valves to a high positive pressure source HP, a low positive pressure source LP, or a negative pressure source NEG. Circuit 1005 connects the blood pump BP1 to the pressure sensor P_BP1, to the low pressure source LP via valve V_BP_POS1, and to the negative pressure source NEG via valve V_BP_NEG1.

[0081] The blood pump operating circuit 1005 within the manifold 260 is shown in Figures 39 and 40. The flow paths are holes and passages in the various blocks of the manifold 260. The low-pressure source LP is a conduit in the horizontal section 272A of the T-shaped manifold, extending along the length of the T-shaped manifold block 272. The negative-pressure source NEG is a conduit parallel to LP, running along the long axis of the T-shaped manifold block 272. Positive pressure flows from the LP conduit through a flow path 1012 located at the top of the T-shaped manifold 272, and then through a hole 1020 in the vertical leg 272B of the T-shaped manifold to the electromechanical valve V_BP_POS1. When valve V_BP_POS1 is open, the positive pressure flows through a hole 1025 in the vertical leg 272B to a passage 1040 located at the top of the T-shaped manifold 272. Next, the low pressure flows through hole 1060 to port 582, where a fitting allows a flexible or malleable line to connect the port to a (remote) blood pump cassette. The pressure in the blood pump connected to port 582 is monitored by a pressure sensor attached to port P_BP1. Port BP1 is located below two upward-facing opposing surfaces of the upper manifold block 276. Port P_BP1 is fluidly connected to passage 1040 via hole 1057 in the upper manifold block 276, passage 1055 at the top of the intermediate manifold block 274, and hole 1050 through the intermediate manifold block 274.

[0082] In the circuit 1005 shown embedded in the manifold assembly 260 in Figure 40, the T-shaped manifold block 272 selectively connects the working chamber of the blood pump cassette (inserted into the cassette receptacle 252 in Figure 23) to either a low-pressure source LP or a negative-pressure source NEG via two valves. A pressure sensor mounted on the upper manifold block 276 is fluidically connected through holes and passages in the upper and intermediate manifold blocks. Other pneumatic circuits can connect the working chamber for the diaphragm pump in the cassette assembly 226 to two of the low-pressure source LP, atmospheric pressure source ATM, and negative-pressure source NEG via valves on the vertical leg 272B of the T-shaped manifold block 272.

[0083] The schematic diagram of the pneumatics in Figure 41 illustrates the pneumatic connections to the various operating ports of the cassette assembly 226. The pneumatic circuit in Figure 41 selectively connects the operating chambers of the various valves (and the two diaphragm pumps shown here) on the external dialysate cassette (ODC) to at least one of the atmospheric pressure source ATM, high positive pressure source HP, low positive pressure source LP, and negative pressure source NEG. Circuit 1100 is an example of a pneumatic circuit that connects the diaphragm valve V_MIX_DT in the ODC cassette to either the ATM or LP pressure source via a three-way valve 1105. Circuit 1200 is an example of a pneumatic circuit that connects the liquid valve V_DISINECT in the ODC cassette to either the HP or NEG pressure source via a three-way valve 1205.

[0084] The Mix_DT valve circuits 1100 and DISINFECT valve circuits 1200 within the manifold 260 are shown in Figures 42 and 43. The flow paths include holes and passages in the various blocks of the manifold 260. The pressure sources ATM, NEG, LP, and HP are conduits arranged along the long axis of the intermediate block 274. The MIX_DT circuit 1100 connects either the low-pressure source LP or the atmospheric-pressure source ATM to the outlet port V_MIX_DT of the MIX_DT liquid valve in the cassette assembly 226. The low-pressure source LP is connected to valve 1105 via passages 1110 and holes 1115 on the bottom surface of the intermediate manifold block 274. The atmospheric-pressure source ATM is connected to valve 1105 via passages 1140 and holes 1145 on the bottom surface of the intermediate manifold block 274. Valve 1105 is connected to outlet port V_Mix_DT via passage 1120 on the upper part of intermediate manifold block 274, hole 1130 through the upper manifold, and hole 1135 through adapter 268.

[0085] The DISINFECT circuit 1200 connects either a high-pressure source HP or a negative-pressure source NEG to the outlet port V_DISINFECT of the DISINFECT liquid valve in the cassette assembly 226. The high-pressure source HP is connected to the valve 1205 via passages 1210 and holes 1215 on the bottom surface of the intermediate manifold block 274. The negative-pressure source NEG is connected to the valve 1205 via passages 1240 and holes 1245 on the bottom surface of the intermediate manifold block 274. The valve 1205 is connected to the outlet port V_DISINFECT via adapter rail 268 through passage 1220 on the top of the intermediate manifold block 274, hole 1222 through the intermediate manifold 274, passage 1224 on the bottom of the intermediate manifold, hole 1226 returning through the intermediate manifold, passage 1228 on the top of the intermediate manifold, hole 1230 through the top of the upper manifold 276, and hold 1235 and passage 1237.

[0086] Figure 43 shows how the above circuitry is physically embedded within the manifold assembly 260. It also shows the mapping of these actuation ports from the array on riser 276B to spatially different arrays of actuation ports on manifold adapter 268, providing an actuation port array that matches the actuation port array of cassette assembly 226.

[0087] Figure 44 shows a pressure distribution manifold 260 installed in a recess 258 of the enclosure or housing 254. This configuration allows for proper alignment between the port 261 on the riser of the pressure distribution manifold 260 and the individual ports on the mating surfaces of the adapters 266, 268, and 270. In this embodiment, the manifold 260 is placed under several insulating materials 264. The insulating materials 264 can be provided between the body of the manifold 260 and the shelf 256. This configuration isolates temperature-sensitive electronic equipment from heated fluids circulating within the components of the enclosure or housing 254.

[0088] As shown in Figure 45, in this embodiment of the hemodialysis machine 246 and enclosure 254, the area occupied by the cassette assembly 226 extends forward from the front of the machine 246. With respect to the user or operator facing the hemodialysis machine 246, the area occupied by the cassette extends beyond the front edge of the shelf 256. For this reason, one or more adapters 266, 268, 270 are configured to provide the necessary mating of the operating port 240 of the cassette assembly 226 to the interface or individual connectors or receptacle ports 266P, 268P, and 270P located on the adapters 266, 268, 270. In this example, the adapters 266, 268, 270 function as a receptacle assembly and provide a first spatial arrangement of receptacle ports that mate to the identically arranged cassette ports 240 of the individual cassettes 194, 196, and 198 of the cassette assembly 226. Figure 46 shows a bottom perspective view of enclosure 254 with interfaces / adapters 266, 268, and 270 attached. This figure clearly shows the extent to which the adapters protrude onto enclosure shelf 256 (and therefore the pressure supply manifold 246 below).

[0089] Figure 32 shows how adapters 266, 268, and 270 are mounted on the top side of manifold risers 276A-C and how they protrude from the front side of manifold 260. The first spatial array of receptacle ports 266P, 268P, and 270P connects to the upper block of manifold 260 or to a second (in this case, more compact) spatial array of output ports 261 of risers 276A-C. Internal passages within adapters 266, 268, and 270 are routed to the individual risers 276A, 276B, and 276C mounted on the corresponding arrays of manifold output ports. Figure 52 shows the manifold / adapter assembly with adapter 266 removed and disassembled, revealing the entire structure of the adapter, as well as risers 276C, 276A, and 276B.

[0090] Figures 47 and 48 are rear views of the manifold 260, showing that risers 276A, 276B, and 276C allow adapters 266, 268, and 270 to slide from the rear of the enclosure to individual positions within the enclosure 254 via slots or notches 280, 282, and 284 in the shelf 256 of the enclosure 254. The risers 276A, 276B, and 276C are made tall enough to allow for the placement of thermal insulation (either rigid foam insulation or other types of insulation) to provide a thermal barrier between the shelf 256 and the body of the manifold 260, as well as to electronic components (control boards, sensors, etc.) located in the recess 258 (see, for example, thermal insulation 269A wrapped around the riser in Figure 48). Figure 48 shows how the assembly, including the manifold 260, its mounted risers and adapters 266, 268, and 270, and other related components, is slid as a group into place within the recess 258 of the enclosure 254.

[0091] Figures 49 to 51 show the engagement between the adapters and their individual rails, and the adapters are positioned within the enclosure to receive cassette assemblies from the cassette loading device in the housing 254. The adapter receptacles or adapter rails 591, 593 and 595 can be integrated with the shelf 256 of the enclosure 254 or can be separate components that can be mechanically mounted to the enclosure 254. In one embodiment, the shelf 256 includes space for receiving or mounting the adapter rails 591, 593 and 595. Figure 48 specifically shows a rear (outside) view of the enclosure 254 with adapters 266, 268 and 270 partially inserted into the individual adapter rails 595, 593 and 591 (shown in Figure 49). The manifold 260 is mounted to the adapters 266, 3268 and 270 before the manifold / adapter assembly slides into its final position within the enclosure 254 as defined by the adapters and adapter rails. As shown in Figure 49, rails 591, 593, and 595 are positioned in spaces 591S, 593S, and 595S, respectively. Figure 49 shows front (inside) views of adapters 266, 268, and 270 partially accepted into the individual adapter rails within the enclosure 254.

[0092] Proper alignment of adapters 266, 268, 270 and pneumatic manifold 260 may be important to ensure that the multiple pneumatic ports 240 of the cassette assembly 226 align with the matching receptacle ports 266P, 268P, 270P to provide the necessary pneumatic connections to the cassette assembly 226. The final placement of the adapters is defined by adapter rails that are securely mounted to the same enclosure that mounts the cassette loader 292 to the roof of the enclosure 254. As a result, the retaining mechanisms for the above components should be appropriately positioned to achieve alignment of the pneumatic ports between the three assemblies, namely the cassette assembly 226, adapters 266, 268, 270, and pneumatic manifold 260. Figure 50 shows the cassette loader 292 with an operating handle 308. The cassette loader 292 can be mounted on the inner surface of the housing or the roof 604 of the enclosure 254. As shown in the figure, the cassette loader 292 and the adapter rails 591, 593, and 595 are positioned on opposing surfaces of the enclosure 254 and maintain a fixed spatial relationship with respect to each other.

[0093] Figure 51 shows an exemplary adapter rail 591 which may comprise a headrest or flange 592 and a tray portion 587 having a raised platform 596, the raised platform 596 which may partially or completely occupy the tray portion 597. The headrest 592 together with the tray portion 597 forms the frame of the rail 591. The tray portion 597 may receive a corresponding adapter, which can be placed on the raised platform 596. The tray portion 597 may also comprise a lattice contour 594 which may be curved according to the end of the corresponding adapter to be received in the rail 591, so that the adapter can slide into the receiving rail. In this embodiment, the tray portion 597 may further comprise a notched region 597 into which the received adapter can interface with a corresponding riser on the pneumatic manifold 260. An elongated slot or groove 611 may optionally be provided between the side of the raised platform 596 and the lattice contour 594. The elongated groove 611 helps to collect any spilled liquid that poses a risk of reaching electronic equipment located below the shelf 256 or in the recessed area 258, thus keeping all spilled liquid or condensation away from the top surface of the installed adapter.

[0094] Figures 52 and 53 show exploded views of an exemplary adapter 266 and its interaction with its corresponding riser 276C. More specifically, Figure 52 shows a top view of the multiple plates and gaskets that can collectively form the adapter 266. Figure 53 also shows a bottom view of the same exploded view of the adapter 266. The adapter is positioned to provide individual pneumatic paths between a first port array of the cassette assembly 226 and a second port array of the pneumatic manifold 260. In this example, the pneumatic ports 240 on the cassette assembly are distributed over an extended surface area that is wider than the narrow dimensions of the manifold assembly 260. The adapter functions to converge the first, larger spatial array into a smaller spatial array of pneumatic ports 261 on the riser of the manifold 260. As shown in Figures 52 and 53, the exemplary adapter 266 may include multiple layers or plates containing pneumatic openings and passages that converge to smaller surface areas as the layers progress toward the individual risers. The upper plate 280 of the adapter 266 includes a pneumatic port 271 and a connecting mechanism for engaging with a subsequent plate of the adapter. The pneumatic port 271 and the connecting mechanism 293 can be seen through the top view of the upper plate 280 in Figure 52 and the bottom view of the upper plate 280 shown in Figure 53. The upper plate 280 is mounted on an intermediate block 286 which includes corresponding pneumatic ports 285 on a first surface 286A. These pneumatic ports 285 coincide with the pneumatic ports 271 on the upper plate 280. The wiper gasket 282 is received by a gasket receptacle 281 recessed in the first surface of the intermediate block 286. The continuous elastomer gasket 282 has a appropriately positioned wiper seal 284 and can be formed from a mold. The wiper seal 284 provides sufficient sealing engagement between the cassette port 240 and the corresponding adapter receptacle port 271, while offering lower frictional resistance to mounting and removing the cassette assembly 226 than, for example, individual O-ring seals.

[0095] Figure 53 shows a second opposing surface 286B of the intermediate block 286. This surface includes a pneumatic passage 286C that fluidly communicates with a port 281 on the first surface 286A. The passage 285C may be positioned to converge and connect the pneumatic port 281 on the first surface 286A to the pneumatic ports distributed on the second surface 286B. As shown, the pneumatic ports on the second surface 286B occupy a smaller area and a different spatial array compared to the pneumatic ports on the first surface 286A. The passage 285C ensures that the pneumatic ports 281 converge toward or shift toward the port array on the riser side of the adapter 266. The second intermediate block 290 may include a pneumatic port 288 that matches the array of pneumatic ports provided on the second surface 286B of the intermediate block 286. A second gasket 289 may be positioned between the first intermediate block 285 and the second intermediate block 290. The gasket 289 enables a proper seal between the first intermediate plate 286 and the second intermediate plate 290, and allows the gasket to be compressed to the extent necessary to form a seal. In one embodiment, a set of alignment mechanisms may be provided on the gasket 289, as well as on one or both of the adjacent plates. In this case, the plates may be the first intermediate block 286 and the second intermediate block 290. Furthermore, the transitional gasket 289 may include pneumatic ports corresponding to the pneumatic port 285 on the first intermediate block 286 and the pneumatic port 288 on the second intermediate block 290. A riser gasket 291 may be placed between the second intermediate block 290 and the corresponding riser (riser 276C in this example). This gasket is positioned to seal the interaction between the second intermediate block 290 and the riser 276C. Multiple gasket alignment mechanisms can be provided on the mating surfaces of the second intermediate block 286 and riser 276C. The above description is intended to also apply to the adapters 268, 270 and the interacting risers 276B and 276A.The number and spatial distribution of pneumatic ports can differ in other adapter-riser interaction embodiments, and in this embodiment they differ.

[0096] When there is pneumatic interaction between ports, the sealing components between ports typically include O-rings. In the case of adapters, multiple O-rings can be used to ensure a seal engagement between mating ports. However, multiple spatially arranged O-rings may exhibit relatively low alignment tolerances when multiple pneumatic ports 240 are inserted into their corresponding adapter ports. In addition to tolerance issues, multiple O-ring connections may create engagement / disengagement forces greater than desired between the cassette assembly 226 and its associated adapter. In an alternative configuration, the web of a wiper gasket can be used to form the required seal and can be mounted between two interacting plates or blocks of the adapter. Figure 53 shows an exemplary wiper gasket 284 that can be molded as a single unit, thereby substantially simplifying the assembly and installation procedure. Figure 54 shows an exemplary wiper gasket used in one of the manifold adapters. Figure 55 shows a cross-sectional view of the wiper gasket of Figure 54 along the line 33H-33H. As shown in the figure, the gasket 284 can be formed to annularly surround the port 285 and to form a conical peripheral recess toward the pneumatic port 285. The gasket 284 can optionally be constructed as a wiper gasket 284 and may include annular nodules or ridges 283 to cover a portion of the port 285. This configuration and structure of the wiper gasket 284 can allow insertion of the cassette port 240 with an acceptable amount of force and can ensure a seal between the adapter and the cassette during operation (i.e., while positive and negative pressure is applied through the adapter port).

[0097] Figures 56 and 57 show a cassette seating device or cassette loader 292 used to fix the first side of the cassette assembly 226 in order to move the cassette assembly linearly toward or toward one or more arrays of receptacle assemblies that are arranged to mate with corresponding arrays of cassette ports 240 on one or more of the cassettes 228, 230, and 232 on the opposing second side of the cassette assembly 226. In the example described below, the receptacle assemblies include manifold adapters 266, 268, and 270, but the cassette loader can be used in any other system in which a ported cassette is inserted into and removed from any type of receptacle array, including, among other things, a fixed multi-port receptacle or a movable connector with an array of ports. The receptacle port to which the cassette operating port is connected may also be mounted directly on the frame, housing, or manifold output port array, rather than on the illustrated exemplary adapters 266, 268, and 270, provided that the two sets of mating ports are arranged to be properly aligned. The cassette seating device 292 has general utility in assisting cassettes with external ports to engage or disengage from mating connectors or receptacle ports on any device.

[0098] Figure 56 shows the cassette loader 292 in storage position, which moves the cassette assembly so that it is linearly away from the receptacle port 261b in Figure 29, or ports 266P, 268P, and 270P in Figures 30, 32, and 45, or more generally, in this example, port 271 in Figure 52, which is arranged on adapters 266, 268, and 270. Note that the cassette seating device or cassette loader 292 can be used to seat a cassette or cassette assembly on or off a receptacle assembly, as long as a single cassette or group of cassettes has either a liquid port or an actuation port on the side opposite to the side to which it is secured by the cassette seating device 292.

[0099] In this example, the cassette seating device 292 comprises a fixed frame 294 including fixed members 296a, b. The fixed members 296a, b are coupled to a link mechanism that interacts with a movable cassette mount 298. The movable cassette mount 298 is configured to hold a cassette or cassette assembly and in this example comprises flanges 300a, b connected to cassette mount rails 302a, b. In this example, the cassette mount rails 300a, b allow the cassette or cassette assembly to slide and hold in place on the seating device 292. Other examples may include a clamping device that can grip the cassette or cassette assembly. In this example, the independent movement of the mounted cassette or cassette assembly is restricted by the presence of one or more cross members 304 that restrict the movement of the upper side of the mounted cassette or cassette assembly, and by the actuator arms 306a, b of the operating handle 308, the actuator arms 306a, b move to a position that prevents lateral movement of the mounted cassette or cassette assembly.

[0100] As shown in Figures 56 to 58, the linkage mechanism may comprise two or more swing arms 310a, b, each of which is pivotally connected to a stationary member 296a, b at a first end 312. Each of the swing arms 310a, b is positioned to move in a plane substantially parallel to the direction of movement of the cassette mount 298 relative to the stationary member 296a, b. The second end of each swing arm 308a, b includes a hub 316 coupled to an axle or pinion 318, the axle / pinion being configured to interact with a flange 300a or 300b substantially parallel to the plane of motion of the swing arms 310a, b. The shaft or pinion 318 is positioned within an elongated slot 320 in the flange 300a or 300b, which converts arc motion toward or away from the fixing members 296a,b at the second ends of the swing arms 310a,b into linear motion toward or away from the fixing members 296a,296b of the cassette mount rails 302a,302b. In this example, the shaft or pinion 318 optionally extends from flange 300a to flange 300b and also functions as a cross member 304. The shaft or pinion 318 can slidably interact with the slot 320 or by other means (e.g., via a circular bearing or wheel positioned in the slot 320).

[0101] To help ensure the linear motion of the cassette mount 298, one or more guide elements (e.g., post 322) may be optionally included to restrict the lateral movement of the cassette mount 298 and the mounting rails 302a, b to which it is attached. The guide element 322 may be firmly attached to or mounted on the fixed frame 294 (or alternatively, on a fixed member 296a, b) and may extend in the desired direction of movement of the cassette mounting rails 302a, b. The guide element 322 may interact with the cassette mount 298 (or alternatively, on a flange 300a or 300b, or on a mounting rail 302a or 302b) via a guide hole 324 (or guide rail, track, or other element), the guide hole 324 which restricts the relative movement of the cassette mount 298 in the longitudinal direction relative to the frame 294 or fixed members 296a, b.

[0102] Figure 56 shows the cassette seating device 292 in a nearly fully retracted position, where the cassette mount 298 is retracted far enough away from the relevant receptacle assembly to release the cassette operating (or liquid) port of the mounted cassette from its individual receptacle ports (see, e.g., Figures 30 and 31). Figures 57–59 show the cassette seating device 292 in an engaged position, where the cassette mount extends linearly away from the fixed frame 294 or fixed members 296a, 296b far enough to engage the cassette operating (or liquid) port of the mounted cassette with its corresponding receptacle ports. The actuator arms 306a, b of the handle 308 are pivotally connected to the fixed members 296a, 296b at their distal ends 326. Each actuator arm 306a, b is also pivotally connected to the first ends of the connecting members 330a, b at their more proximal portions 328. Next, the second ends of the connecting members 330a, b are pivotably connected to an actuator bar 332, which has pivotal connections to the second ends of each swing arm 310a, b, including the linkage mechanism of the cassette seating device 292. The connecting member 330a or 330b moves eccentrically with respect to the rotation axis of the actuator arm 306a or 306b, thereby displacing the actuator bar 332a, b and the swing arms 310a, b away from the fixed members 296a, 296b.

[0103] Optionally, a cassette mount retaining member 334 can be used to hold the cassette mount 298 in the retracted position. In one example, the cassette mount retaining member 298 may include a pawl that is pushed aside by the cross member 304 (or alternatively, another element attached to the cassette mount 298, flange 300, rail 302, or shaft / pinion 318) when the handle 308 is fully retracted into the retracted position (see Figure 56). When the cross member 304 reaches the recess 336 of the pawl, the pawl descends and engages with the cross member 304, holding the cassette mount 298 in its retracted position. In additional or alternative embodiments, the handle 308 may include a movable plunger element (replacing the handle post 338 (see Figures 57, 59)) that can engage with or pass through a hole or recess (not shown) in the front flange 340 of the fixed frame 294. Optionally, the plunger can be spring-loaded so as to automatically engage with the front flange when the handle 308 is released by the user.

[0104] As applied to hemodialysis enclosure 254 (see Figure 23), the cassette seating device 292 can be mounted on the ceiling inside enclosure 254, as shown in Figures 45 and 46. This is located opposite the receptacle assemblies 266, 268, and 270 (in this case, the manifold adapters). The cassette assembly 226 can be seen mounted on the cassette seating device 292 by the cassette assembly frame plate 513, as shown, for example, in Figures 21 and 46. In Figures 30 and 31, the cassette assembly port 240 is shown to be directly adjacent to the corresponding receptacle port on the receptacle assembly and is completely disengaged from the receptacle port when the handle 308 is placed in the stowed position (Figure 30).

[0105] Pneumatic pump system using binary valves Figure 60 is a schematic diagram showing one embodiment of a pressure-actuated system 14000 for a positive displacement diaphragm pump ("pod pump") 234 as shown in Figure 20. In this example, pneumatic pressure is used as the control fluid (for example, so that the pump is driven by pneumatic pressure). In other embodiments, other fluids (for example, water or a water-based solution) may also be used as the control fluid.

[0106] In Figure 60, the pressure-actuated system 14000 alternately supplies positive and negative gas pressure into the working chamber 14020 of the pod pump 23a. The pneumatically actuated system 14000 includes a working chamber pressure transducer 14020, a positive supply valve LP1, a negative supply valve N1, a positive pressure gas source LPOS, a negative pressure gas source NEG, a positive pressure source pressure transducer (not shown), a negative pressure source pressure transducer (not shown), and an electronic controller 14035. The electronic controller receives pressure data from the pressure sensor 14020 and controls valves N1 and LP1 to control the operation of the pump 23a. These two valves are controlled by the electronic controller 14035 (alternatively, a single three-way valve may be used instead of the two separate valves LP1 and N1). In some cases, the positive supply valve LP1 and the negative supply valve N1 are binary on / off valves that are either fully open or fully closed.

[0107] The positive pressure source LPOS supplies positive pressure control gas to the working chamber 14020, biasing the diaphragm 14025 toward the position that minimizes the volume of the pumping chamber 14027 (i.e., the position where the diaphragm contacts the rigid wall of the pumping chamber). The negative pressure source NEG supplies negative pressure control gas to the working chamber 14020, biasing the diaphragm 14025 in the opposite direction toward the position that maximizes the volume of the pumping chamber 14027 (i.e., the position where the diaphragm faces the rigid wall of the working chamber).

[0108] Controller 14035 can also receive pressure information from three other pressure transducers (working chamber pressure transducer 14020, transducer on LPOS, and transducer on NEG). As their names suggest, these transducers measure the pressure in the working chamber 14020, the positive pressure source LPOS, and the negative pressure source NEG, respectively. Controller 14035 monitors the pressure in the two pressure sources LPOS and NEG to ensure they are properly pressurized (either positive or negative). A compressor-type pump can be used to maintain the desired pressure in the reservoir containing the LPOS and NEG pressure sources.

[0109] In one embodiment, the pressure supplied by the positive pressure reservoir LPOS is under normal conditions large enough to fully bias the diaphragm 14025 against the rigid wall of the pumping chamber. Similarly, the negative pressure (i.e., vacuum) supplied by the negative pressure source NEG is preferably large enough under normal conditions to fully bias the diaphragm against the rigid wall of the working chamber. However, in a preferred embodiment, the positive and negative pressures supplied by the pressure sources LPOS and NEG are kept within sufficient safety limits to avoid excessively high fluid pressures that could harm the patient to whom the pump system may be connected.

[0110] The controller 14035 monitors pressure information from the working chamber pressure transducer 196 and, based on this information and possibly a timer, controls the valve mechanism (valves LP1, N1) to fully bias the diaphragm 14025 to its minimum pumping chamber volume position, and then switches the pressure to fully pull the diaphragm 14025 back to its maximum pumping chamber volume position.

[0111] The pressure-operated system comprises a pressure distribution manifold which may include an operating chamber pressure transducer 14020, a transducer for the LPOS source, a transducer for the NEG source, a positive supply valve LP1, and a negative supply valve N1. A controller 14035 may be mounted on the manifold, and the positive pressure gas source LPOS and the negative pressure gas source NEG may include conduits that penetrate the manifold. The manifold may be configured to fit completely or largely into a recess 258 of the hemodialysis housing (see, for example, Figures 44 and 48). In this configuration, components that come into contact with blood or dialysate (i.e., the pod pump 23a, the inlet valve 192, and the outlet valve 193) may be located within an insulated enclosure 254 or front panel 248 (see Figure 23) so that the pump, valves, and interconnected fluid pathways can be more easily accessed and / or sterilized.

[0112] Pumping process using binary valves The process of pumping liquid through the pod pump 23a can be better understood by referring to Figures 61 and 62. Referring here to Figure 61, the target pressure 14050 and the actual pressure 14055, measured by the pressure sensor 196 (Figure 60), are plotted against the time for one delivery stroke and one filling stroke. The delivery stroke involves using positive pressure from an LPOS source to drive the diaphragm 14025 from one side of the pump pod 23a to the other, thereby discharging the liquid in the pumping chamber 14027. In contrast, the filling stroke uses sub-atmospheric pressure from a NEG source to pull the diaphragm 14025 back across the pod pump 23a, thereby filling the pod pump with liquid. In some examples, the filling stroke is completed by connecting the working chamber 14020 to the atmosphere, allowing the liquid pressure in the system to drive the diaphragm across the pod pump chamber.

[0113] In the binary valve-driven pump 14000, the delivery and filling pump strokes include multiple charge cycles that generate the jagged pressure traces 14050 shown in Figures 61 and 62. Details of the start of the delivery stroke are shown in Figure 62. In this figure, during the movement of the liquid, the actual pressure 14055 rises when valve LP1 is open and falls when valve LP1 is closed. In the delivery stroke, the movement of liquid from the pumping chamber 14027 reduces the volume of the pumping chamber, and since the total volume of the pod pump is fixed, this increases the volume of the working chamber 14020. As the volume of the working chamber increases, the pressure in the working chamber decreases when the pneumatic valve LP1 is closed. The charge cycle includes the pressure rise due to the valve being open and the pressure decay when the valve is closed. The length of the charge cycle can vary as shown in Figure 62. Three complete charge cycles are shown here, each with a different duration. Figure 62 plots the details of the discharge stroke under positive pressure. Referring here to the filling stroke relative to Figure 61, the pressure trace 14055 has a similar jagged pattern. However, during the filling stroke, when the N1 valve is opened, the pressure drops rapidly, exposing the working chamber to the NEG pressure source, and when the N1 valve is closed, it slowly recovers toward atmospheric pressure. In this case as well, the charge cycle involves a rapid increase in the magnitude of the working chamber pressure and a slower pressure decay toward atmospheric pressure when the N1 valve is closed.

[0114] While conventional applications and disclosures have used continuously variable valves to control diaphragm pumps, this specification describes binary valves that are either fully open or fully closed and not designed to be partially open. Binary valves and associated control electronics are generally less expensive than variable-open valves. Furthermore, binary valves may require less functional checks / monitoring and may be less sensitive to the presence of waste in the pneumatic passages leading to or away from them. Digital functions or on / off functions inherent to binary valves require proprietary control algorithms for pressure control, stroke end detection, and flow path blockage.

[0115] The controller 14035 controls valves N1 and LP1 according to several algorithms that may be executed sequentially or simultaneously based on signals received from the pressure sensor or transducer 196. These control algorithms are specific to binary valves due to their unique digital or on / off functions. The control algorithms include algorithms for controlling the fluid flow rate through the pump, algorithms for controlling the pressure in the working chamber 14020, algorithms for detecting the end-of-stroke (EOS) condition, algorithms for detecting complete occlusion of the inlet line, algorithms for detecting complete occlusion of the outlet line, algorithms for detecting partial occlusion, and algorithms for measuring access metrics (indicators of the quality of blood flow obtained from the patient's venous or fistula access).

[0116] The controller 14035 calculates information about the fluid flow through the pump based on the pressure signals from the sensor 196 when valves N1 and LP1 are closed. The controller 14035 uses the received pressure data to control the working chamber pressure, detect EOS, blockage, and partial blockage, and determine the access metric.

[0117] Explanation of pressure control The flow rate through a pneumatically operated diaphragm pump, such as a pod pump 23a, is controlled by setting a target pressure in the working chamber 14020. Next, the pod controller 14035 controls the pressure within the working chamber 14020, measured by a pressure sensor 196 fluidly connected to the working chamber, by controlling valves N1, LP1, which fluidly connect the pressure source to the pump's working chamber. In an exemplary control algorithm, the controller averages the pressure data from the pressure sensor 196 while the binary valves N1, LP1 are closed, and opens valves N1, LP1 when the cumulative average pressure approaches or equals the target pressure. In one example, the controller 14035 closes valves N1, LP1 when the magnitude of the pressure data is greater than or equal to the target pressure. In another example, the controller 14035 closes valves N1, LP1 when the magnitude of the pressure data is greater than or equal to the target pressure minus a predetermined constant value. In another example, a given value is not constant but varies with the direction of the stroke and the duration or stage of the stroke. In yet another example, the controller 14035 integrates the magnitude difference between the measured pressure and the target pressure, and opens valve N1, LP1 when the integrated difference approaches or equals zero.

[0118] The fluid flow through the pump is controlled by the magnitude of the negative pressure applied to the working chamber to fill the pumping chamber with liquid, and the magnitude of the positive pressure applied to the working chamber to discharge the liquid from the pumping chamber. In some examples, the pod pump controller 14035 is programmed to receive or calculate the desired flow rate and / or maximum displacement of the pod pump 23a. The controller 14035 may set initial target pressures for the filling and discharging strokes. The controller controls the pressure in the working chamber to reach or approach the target pressure. The controller monitors the time to complete the stroke and determines the actual flow rate by dividing the displacement by the time to complete the stroke. The controller 14035 may change the target pressure based on the difference between the most recent actual flow rate and the desired flow rate. For example, the controller 14035 may increase the target pressure if the measured actual flow rate is below the desired flow rate. In another example, the controller may decrease the target pressure if the measured actual flow rate is above the desired flow rate. The controller 14035 may change the discharging stroke independently of the filling stroke. In one example, the controller 14035 may use a feedback loop that modifies the target discharge pressure based on the flow rate measured during the discharge stroke to achieve a desired flow rate. In another example, the feedback loop modifies the negative target discharge pressure based on the flow rate measured during the discharge stroke to achieve a desired filling rate.

[0119] In conventional disclosures, a chamber connected to a pressure source by a binary valve was controlled based on a limit on the target pressure. The controller connects the pressure source to the chamber by opening the valve between them when the magnitude of the measured pressure in the chamber is a predetermined amount lower than the magnitude of the target pressure. The controller then closes the valve when the magnitude of the measured pressure in the chamber reaches a second predetermined value that exceeds the magnitude of the target pressure. In some cases, applying this limiting approach to a pneumatic diaphragm pump produces an average chamber pressure magnitude that is smaller than the target pressure magnitude. In some cases, opening the valve causes the magnitude of the pressure in the chamber to increase very rapidly, while the decrease in the magnitude of the pressure due to the fluid flowing in and out of the pumping chamber is much slower. This mismatch in the rate of pressure change causes the time-averaged pressure magnitude to be lower than the target pressure magnitude. Since the offset between the average pressure and the target pressure also changes over time as the fluid flow in and out of the pump changes over time, it is difficult to continuously compensate for the mismatch in the rate of pressure change.

[0120] The pressure in the working chamber can be controlled by comparing the measured pressure with a target pressure. The controller opens and closes a pneumatic valve connecting the working chamber to a pressure source or reservoir. During the delivery stroke, the controller can open and close valve LP1 to maintain the pressure in the working chamber 14030 near the delivery target pressure 14052. During the filling stroke, the controller 14035 opens and closes valve N1 to maintain the pressure in the working chamber 14030 near the filling target pressure 14054. In one example, the controller closes the pneumatic valve when the magnitude of the measured pressure exceeds the target pressure and opens the pneumatic valve again when the average measured pressure in the working chamber approaches or equals the target pressure.

[0121] In the algorithms shown in Figures 63 and 64, referring to Figure 62, the controller 14035 controls valves N1, LP1 to maintain the average pressure in the working chamber 14020 at the target pressure by maintaining the average pressure in the working chamber at the target pressure while valves N1, LP1 are closed, as described below. Now referring to the pressure control algorithm 14100 in Figure 63 and also to Figure 60, the pump controller (which may be separate from or distinct from the controller 14035 in Figure 60) selects the stroke direction 14105 and target pressure, filling and PTF (pressure-target-fill), or discharge and PTD (pressure-target-discharge). If the filling stroke is selected, at 14110, the controller 14035 opens the valve that fluidly connects the NEG pressure source or reservoir to the working chamber 14020, and at 14120, monitors the pressure sensor 196. In each time step in block 14130, the controller evaluates whether the magnitude of the pressure is greater than or equal to the magnitude of the target pressure; if not, it leaves the valve open. In block 14140, if the magnitude of the measured pressure is equal to or greater than the target pressure, the N1 valve is closed. In block 14150, the difference between the measured pressure P and the target pressure TTF is summed at each time step. In block 14160, the end-of-process function or algorithm checks for end-of-process, and if the EOS criterion is met, the controller logic proceeds to end-of-process 14200. Note that the logic in block 14160 may be located anywhere between 14140 and 14180 in the flowchart, or it may be a function separate from the pressure control algorithm 14100. In block 14170, the summed pressure difference is compared to zero. If the summed pressure difference is greater than zero, the controller logic returns to 14150 for an additional time step. If the sum of the pressure differences is zero or less, the controller logic resets the sum of the pressure differences to zero in block 14180 and returns the logic to block 14110, where the N1 valve is opened.

[0122] A single controller can control the timing of the pump stroke, the setting of the target pressure, and the operation of the pneumatic control valve. Alternatively, the tasks can be divided among two or more controllers. For example, a main controller determines the timing of the pump stroke and the target pressure, while a sub-controller controls the pneumatic control valve. Referring to Figures 63 and 60, once the main controller selects the delivery stroke, the main controller also specifies the target pressure, and the sub-controller moves the logic to block 14210 (Figure 63), where the LP1 valve is opened. In a series of steps similar to the filling process, the pressure in the working chamber 14020 is monitored by the pressure sensor 196 in block 14220. Block 14230 evaluates the pressure against the target pressure, and if the measured pressure is greater than or equal to the target pressure, the logic moves to block 14240, where the LP1 valve is closed. Referring to Figure 60, after being instructed in 14051 to close the LP1 valve, the chamber pressure 14055 continues to increase until the chamber pressure exceeds the target pressure. The chamber pressure 14055 may increase to 14052 due to delays in valve closure and due to fluid / thermodynamic factors that may affect the chamber pressure.

[0123] Referring to Figure 63, in block 14250, the difference between the chamber pressure P and the target pressure PTD is summed with respect to each time step. This sum of the difference between the chamber pressure P and the target pressure PTD from point 14052 until the chamber pressure 14055 equals the target pressure 14050 is region 14080 in Figure 62. Region 14085 is the sum of the difference between the chamber pressure and the target pressure when the magnitude of the chamber pressure 14055 is less than the magnitude of the target pressure 14050. Referring again to Figure 63, the EOS algorithm is executed in block 14260, and if EOS is detected, the process ends at 14200.

[0124] In block 14270, the sum of the pressure differences from block 14250 is evaluated. Block 14270 then moves the logic to 14210, where the LP1 valve is opened again if the sum of the pressure differences is zero or less. Before the logic reaches block 14210, the sum of the pressure differences is set to zero in block 14280, at which point LP1 is opened. Alternatively, the sum of the pressure differences may be set to zero at any point in the logic after block 14270 and before block 14240.

[0125] Referring to Figure 62, the criterion for block 14270 can be graphically represented as an instance where the region of 14080 is equal to the region of 14085. The criterion for block 14270 is satisfied when the sum of the actual pressure 14055 minus the target pressure 14050 (if the actual pressure is greater than the target pressure) is equal to the sum of the target pressure 14050 minus the chamber pressure 14055 (if the chamber pressure is also less). Alternatively, the criterion for 14270 is satisfied if the sum of [the magnitude of the average pressure minus the magnitude of the target pressure] is zero or less.

[0126] In one example, in blocks 14130 and 14230, the chamber pressure P is compared to predetermined pressures PD and PF, which differ from the target pressures PTD and PTF by a pressure offset. In some examples, to limit pressure overshoot, the magnitudes of PD and PF are predetermined values ​​smaller than the magnitudes of the target pressures PTD and PTF. Referring here to Figure 62, when PD is less than the target pressure (14050D), the signal to valve LP1 in Figure 60 is sent earlier, resulting in a lower peak pressure at 14052. In one example, the magnitude of the pressure offset differs between the filling and discharging strokes because the average pressures for the filling and discharging strokes are different.

[0127] The delay in valve operation is a fixed value, and the pressure overshoot is inversely proportional to the volume of the working chamber (which changes during the stroke). Therefore, as can be observed in Figure 61, the overshoot also changes. Generally, the overshoot is maximum at the start of the discharge stroke 14060 and at the end of the filling stroke 14075 when the volume of the working chamber 14020 is at its minimum. The offset for the filling and discharge strokes may change during the stroke. In one example, the magnitude of the offset is maximum at the start of the discharge stroke and decreases with each charge cycle until the offset reaches its minimum value. In the same or another example, the magnitude of the offset is minimum at the start of the filling stroke and increases with each charge cycle until the offset reaches its maximum value. The offset value may vary with time, the number of charge cycles, the valve openings, or the sum of the differential pressures when the valve is closed during the stroke.

[0128] Another example of the pressure control algorithm 14300 is shown in Figure 64. Algorithm 14300 is similar to algorithm 14100 except for elements 14350, 14370, 14380, 14450, 14470, and 14480, in which the difference between the measured pressure and the target pressure is replaced by the average pressure. In blocks 14350 and 14450, the measurements from the pressure sensor 196 are averaged while valves N1, LP1 are closed. In blocks 14370 and 14470, if the average pressure, PAVG is equal to the target pressure within some predetermined margin, the logic proceeds to blocks 14110 and 14210, respectively, after zeroing the average pressure, and then opens valves N1, LP1.

[0129] Detection of the end of the process The accurate or reliable determination of the flow velocity and flow rate through pump 23a, as shown in Figure 60, relies on an accurate or reliable algorithm for determining the end of stroke (EOS). The end of stroke occurs when the diaphragm 14025 moves across the cavity of the pump body and reaches one of the walls of the pump body. The controller 14035 detects the state of the chamber against the wall by observing that the magnitude of the chamber pressure measured by the pressure sensor 196 does not decrease when valves N1, LP1 are closed. The chamber pressure does not decrease because the diaphragm 14025 cannot move in contact with the chamber wall and therefore cannot change the volume of the working chamber 14020.

[0130] The EOS detection algorithm detects the end-of-stroke state based on the valve state, chamber pressure, and the rate of change of chamber pressure. This algorithm detects the EOS state for a pneumatically driven diaphragm pump. In this case, the air pressure is controlled by a pneumatic valve connecting the pump to a pressure reservoir, a pressure sensor that measures the air pressure applied to the pump, and a controller that communicates with the pump and the pneumatic valve. In one example, EOS detection is based on the number of charge cycles performed by the pneumatic valve and the rate of pressure change while the pneumatic valve is closed. In another example, EOS is declared when a predetermined number of charge cycles have occurred and the rate of change of the magnitude of the pressure is less than a predetermined rate. In yet another example, EOS detection is declared when a predetermined number of charge cycles have occurred, the pressure is within a predetermined range, and the rate of change of the magnitude of the pressure is less than a predetermined rate.

[0131] Referring here to Figure 60, the controller 14035 changes the stroke direction from discharge to fill or from fill to discharge after detecting the end of a stroke (EOS). The end of a stroke algorithm is schematically shown in Figure 65 and can be understood by referring to Figure 61. The EOS algorithm 14300 is executed in blocks 14160 and 14260 as part of the pressure control algorithm 14100, or the EOS algorithm may be executed in parallel. Block 14310 monitors the pressure in the working chamber as sensed by the pressure sensor 196 (Figure 60). In block 14320, the number of charge cycles that occurred during the current stroke is compared to a predetermined number. If more charge cycles than the predetermined number occur, in block 14330, the minimum rate of change of the pressure magnitude (dP / dt) is compared to a predetermined rate (dPEOS). If the minimum rate of change is less than the predetermined rate, in block 14340, the difference between the current pressure P and the target pressure PT is evaluated. If the difference is less than a predetermined difference DP, EOS is declared, and the controller changes the pump stroke, target pressure, and switches the state of hydraulic valves 192 and 193 (the valves in the dialysis system described herein may be diaphragm valves that can also be actuated by pressure supplied by the manifold and controlled by the controller). If the difference between the chamber pressure and the target pressure is greater than a predetermined difference, the controller 14035 declares occlusion.

[0132] Continuing to refer to Figure 65, in block 14330, dP / dt is the minimum rate of change of the pressure magnitude in the working chamber. In some examples, the minimum rate of change is determined only while the pneumatic valves N1, LP1 are closed. In some examples, the minimum rate of change of the pressure magnitude is derived from low-pass filtering of the pressure value. In another example, the rate of change of the pressure magnitude itself is low-pass filtered before being compared to a predetermined rate of change of pressure (dPEOS).

[0133] Blockage detection Referring here to Figure 60, the controller 14035 can be configured to detect blockages in the flow to and from the pump 23a. The user interface may notify the user as an alert or alarm if the inspiratory or outlet line is blocked. In one example, the user may be instructed to inspect the blood lines 203 and 204 for twisting, compression, or other blocking elements. The blockage detection algorithm can be considered a safety feature to prevent thrombosis in the blood circuit, or it can identify problems with fluid flow in the water circuit or dialysate circuit.

[0134] Blockages in the pump inlet and outlet lines are detected by the controller 14035 based on information received from the pressure sensor 196, while the working chamber 14020 is isolated from the pressure reservoirs NEG and LPOS. The pressure sensor 196 measures the pressure in the working chamber. The controller 14035 detects blockages in the inlet line during the filling stroke and blockages in the outlet line during the dispensing stroke. The controller 14035 sums the pressure changes that occur in the working chamber while valves N1 and LP1 are closed. The controller 14035 determines the presence of a blockage by comparing the sum of pressure changes across all charge cycles during a single pump stroke with the sum of pressure differences during previous strokes and a predetermined value. The controller 14035 may also detect blockages based on the number of charge cycles completed before the end of a stroke is detected, and / or the difference between the working chamber pressure and the target pressure.

[0135] Referring here to Figure 66, the occlusion algorithm 14400 is shown as a flowchart that begins in step 14410, where either the filling or discharging stroke is initiated by setting a target pressure and then opening valves N1, LP1 (Figure 60) in step 14415. Valves N1, LP1 are closed in step 14420. In step 14425, the controller sums the pressure changes (dPSUM) while the pneumatic valves N1, LP1 are closed. The sum of pressure changes (dPSUM) is summed over the entire stroke, which includes multiple charge cycles 14427. In one example, the controller 14035 determines the pressure change from the previous time step to the current time step. During each time step while the pneumatic valves N1, LP1 are closed, Pi-1-Pi is calculated and this pressure change is added to the current sum of pressure changes. In one example, the controller determines the pressure change between the closing and reopening of valves N1, LP1, and then adds this pressure change to the sum of pressure changes (dPSUM) which includes all pressure changes since the start of the stroke in step 14410.

[0136] Continuing to refer to Figure 66, the occlusion algorithm 14400 updates the sum of pressure changes (dPSUM) in step 14425, and then checks the end-of-cycle status in step 14430. If no EOS is detected, the controller 14035 checks in step 14435 to determine whether the charge cycle is complete and whether it is time to reopen the valves. The end-of-charge cycle step 14435 can be performed based on one or more parameters, including (but not limited to) the current pressure, the average pressure during the current charge cycle, or the integral of the pressure difference between the target pressure and the chamber pressure during the current charge cycle. If step 14435 determines that the charge cycle is not complete, the sum of pressure changes is updated for the next time step in step 14435. Once the charge cycle is complete, the pneumatic valves N1, LP1 are reopened in step 14415.

[0137] If a stroke termination is determined in step 14430, the occlusion algorithm 14400 proceeds to several independent occlusion tests in steps 14440, 14450, 14455, and 14460. Step 14440 moves the logic to the low-sensitivity step 14450 and the high-sensitivity step 14445. In one example, step 14440 selects low sensitivity for a short or partial stroke of the blood pump due to the variability of short strokes within the blood pump. In a short stroke, the diaphragm is not driven to contact the inner wall of the pod pump. Instead, the delivery stroke is shortened. In some medical applications, a short delivery stroke may be beneficial in reducing damage to blood cells between the diaphragm 14025 and the wall of the pod pump 23a. Short strokes have greater variability, and a low-sensitivity occlusion test in step 14450 may be recommended to avoid false occlusion detection. In one example, for all non-short stroke operations, step 14440 transitions the logic to step 14445.

[0138] Continuing to refer to Figure 66, the blockage algorithm 14400, in step 14445, compares the sum of pressure differences (dPSUM) during the just completed stroke with the sum of pressure differences (dPGOOD) for the last good stroke in the same direction. In one example, a blockage is detected when two consecutive strokes in the same direction have a dPSUM that is less than 30% of the last good stroke (dPsum). More generally, a blockage is detected when one stroke has a dPSUM that is less than a predetermined percentage of the last good stroke (dPsum). In one example, a blockage is detected when three or more strokes have a dPSUM that is less than a predetermined percentage of the last good stroke (dPsum). When a blockage is detected, the logic proceeds to step 14470, where a blockage alert or alarm is sent to the user interface (UI), and in one example, the pump may be stopped. In some embodiments, the UI indicates which pump and where the inlet or outlet line is blocked. If no blockage is detected at step 14445, the logic proceeds to step 14455.

[0139] Figure 66 shows an overview of the blockage algorithm 14400, which in the low-sensitivity step 14450 includes a comparison of the sum of pressure differences (dPSUM) during the just-completed stroke with the sum of pressure differences (dPGOOD) for the last good stroke in the same direction. In one example, a blockage is detected when three consecutive strokes in the same direction have a dPSUM that is less than 10% of the last good stroke (dPsum). In another example, a blockage is detected when one stroke has a dPSUM that is less than a second predetermined percentage of the last good stroke (dPsum). Alternatively, a blockage is detected when four or more strokes have a dPSUM that is less than a predetermined percentage of the last good stroke (dPsum). When a blockage is detected, the logic proceeds to step 14470, where a blockage alert or alarm is sent to the user interface (UI), and in one example, the pump is stopped. In one embodiment, the UI indicates which pump and where the inlet or outlet line is blocked. If no blockage is detected at step 14450, the logic proceeds to step 14455.

[0140] In step 14455, the controller 14035 detects a blockage if, in one or more consecutive strokes in the same direction, either fewer than a predetermined number of charge cycles occur, or the sum of pressure changes (dPsum) is less than a predetermined limit (dPsum_limit). In one example, a blockage is detected if either condition occurs in three consecutive strokes in the same direction. In another example, a blockage occurs if either condition occurs in two consecutive cycles. In yet another example, the predetermined number of charge cycles is 5. In yet another example, the predetermined number of charge cycles is half the number of charge cycles in a typical stroke. If a blockage is detected, the logic proceeds to step 14470, where a blockage alert or alarm is sent to the user interface (UI). In one exemplary response, the pump is stopped. The controller may send data to the UI indicating which pump is affected and whether the blockage occurred in the inlet line or the outlet line. If no blockage is detected in 14455, the logic proceeds to step 14460.

[0141] In step 14460, the controller 14035 detects an obstruction if the pressure in the working chamber 14020 is significantly greater than the target pressure for a predetermined period of time. In one example, step 14460 detects an obstruction if the pressure in the working chamber 14040 is more than 60 mmHg greater than the target pressure for a predetermined period of time. In another example, the predetermined period in step 14460 is 25% of the stroke duration, where the stroke duration is the time from the start of the stroke to EOS detection.

[0142] Detection of partial blockage Partial blockage can limit flow but does not obstruct flow in the fluid line. Depending on whether partial or complete blockage is detected, the function of the hemodialysis machine may be changed and / or the message to the user may be changed. The controller detects partial blockage based on the flow rate of the most recent stroke and the stroke target pressure for that most recent stroke. If the flow rate of the last stroke falls below the desired flow rate, the pump controller changes the target pressure to achieve the desired flow rate and increases the target pressure for the next stroke. A given pump has a maximum target pressure, which may be a function of the pressure reservoir pressure and / or the usage of the given pump. In one example, partial blockage can be declared if the recent flow rate passing through the pump does not reach the desired flow rate, even though the target pressure for the most recent stroke is set to the maximum value. In another example, partial blockage can be declared if the flow rate of the most recent stroke is less than 75% of the desired flow rate, even though the target pressure for the most recent stroke is set to the maximum value. In hemodialysis systems, a partial occlusion detection function can be applied to the blood pump to determine if there are problems with an individual's vascular access or the placement of a set of blood lines.

[0143] Blood flow metrics In one embodiment, the controller may be programmed to provide the user of an extracorporeal or hemodialysis system with an index of blood flow metrics (the quality or rate of blood flow from venous access or arteriovenous fistula) during the course of each pump filling stroke. For example, flow metric values ​​that provide the user with a continuous index of the quality or adequacy of blood flow in the blood line under treatment may be transmitted to a graphical user interface. The user interface (e.g., an electronic tablet) may provide the user with raw flow metric data. In another embodiment, the flow metric may be scaled proportionally to a range of 1 to 5, where a value of "5" represents, for example, excellent flow, a value of "3" represents limiting flow, and a value of "1" represents occluded flow. Thus, flow metric values ​​within a specified range can be mapped to each of the set values ​​from "1" to "5" to simplify the user's interpretation of the adequacy of blood flow in the blood line. In yet another embodiment, the flow metric may be displayed graphically to the user, for example, as a moving or zooming bar graph, a dial gauge, or a set of colored lights.

[0144] In a preferred embodiment, a critical or suboptimal flow metric may cause the controller to issue an alert to the user, as a result of which the user can attempt to improve blood flow in the blood line (e.g., repositioning the line, straightening the line, adjusting the vascular access cannula). The controller may be programmed to initiate a procedure to pause or stop the dialysate pump, including signaling the user to provide sufficient time before pausing or stopping the dialysate pump, so that the user can correct the condition. The user may be alerted about low flow conditions during the filling stroke, so that timely adjustments by the user can restore the flow metric to an acceptable value before the filling stroke is completed. Alternatively, the controller may be programmed to allow suboptimal flow metric values ​​for two or three (or more) consecutive filling strokes before instructing the controller to stop the dialysate pump. Thus, timely correction of low flow conditions by the user can avoid interruptions in the dialysate pump operation and, in some cases, avoid interruptions in treatment. In one example, the controller may be programmed to pause or stop the dialysate pump if the flow metric remains below 150 (e.g., as dP / dt at mmHg / sec) during three consecutive filling strokes, and not restart the dialysate pump during five consecutive blood pumping strokes until the flow metric exceeds 200. In some of these embodiments, the controller allows the blood pump to continue operating while the dialysate pump is stopped, and as a result, the user has the opportunity to restore a blood flow condition that allows the dialysate pump to be restarted, thereby avoiding premature termination of treatment.

[0145] Referring here to Figures 60 and 62, the controller 14035 can determine the flow metric during a filling stroke based on the pressure in the working chamber while the pneumatic valve N1 is closed. The pressure in the working chamber is measured by a pressure sensor 196 communicating with the controller 14035. In one example, the controller 14035 can determine the flow metric based on the rate of change of the signal from the pressure sensor 196 while the valve N1 is closed. In another example, the controller 14035 can determine the flow metric based on the minimum rate of change of the working pressure during the stroke while the valve N1 is closed (i.e., the lowest or near-lowest rate of pressure change detected by the controller). In yet another example, the controller 14035 can determine the flow metric based on the minimum rate of change of the working pressure during the stroke, excluding the charge cycle that generated the stroke end signal. In one example, the rate of change of the working pressure is determined during each charge cycle using a low-pass filter, and the minimum rate of change for each charge cycle is low-pass filtered over the stroke to determine the flow metric.

[0146] Figure 67 shows the flowmetric algorithm 14500 as a flowchart initiated with “Initiation of Filling Stroke” using a blood pump (23a in Figure 60). The upstream valve 192 is opened and the downstream valve 193 is closed. The filling stroke is continued by opening the pneumatic valve N1 in step 14515 and closing valve N1 in step 14520 to generate a desired negative pressure or pressure below ambient pressure in the working chamber 14020 of the blood pump 23a. The negative pressure in the working chamber 14020 draws blood from the access site through the tube 203 into the pumping chamber of the blood pump 23a. The magnitude of the negative pressure in the working chamber 14020 decreases as the filling pump chamber expands and compresses the gas in the working chamber 14020. This decrease in the magnitude of the negative pressure is sensed by the pressure sensor 196 and notified to the controller 14035 in step 14525 (Figure 67). The controller analyzes the data and (optionally) uses a low-pass filter (LPF) function to determine the rate of change (dP / dt) of pressure in the working chamber in step 14530. If the end of the charge cycle occurs, step 14535 moves the logic to step 14540, where the end of the stroke (EOS) is determined. If the end of the charge cycle does not occur, the logic moves to 14525, where the pressure signal continues to be monitored. If no EOS is detected in step 14540, the controller determines the minimum magnitude of dP / dt while valve N1 is closed in step 14545. The current minimum or lowest dP / dt for the charge cycle detected by the controller is then used in the LPF to update the minimum dP / dt for the charge stroke in step 14550, and valve N1 is reopened in step 14515 to start the next charge cycle. If EOS is detected in step 14540, the logic proceeds to step 14555, where the pod controller 14035 reports the minimum dP / dt to the controller, which converts the minimum dP / dt value into an indicator that is easier to understand and displayed on the user interface (UI).The UI can be a graphical display unit such as a tablet computer. The indicator is the flow metric of the intake blood line and access. In one example, the minimum dP / dt value is displayed as a value from 1 to 5, where 1 is occluded access, 3 is limited access, and 5 is free flow access. Here, access refers to the needle or cannula system, the placement of the needle or cannula, and the restriction of flow at the inlet to the needle or cannula. In one example, the flow metric is 1 for a minimum dP / dt less than 25 mmHg / s, or occluded; the flow metric is 2 for a minimum dP / dt between 25 and 50 mmHg / s, or insufficient; the flow metric is 3 for a minimum dP / dt between 50 and 75 mmHg / s, or limited; the flow metric is 4 for a minimum dP / dt between 75 and 100 mmHg / s, or good; and the flow metric is 5 for a minimum dP / dt between 100 and 125 mmHg / s, or excellent. In addition to displaying the flow metric on the UI in step 14555, the flow metric algorithm 14500 in step 14560 evaluates the flow metric and issues an alert to the user 14570 if the flow metric remains below a predetermined value beyond a predetermined number of strokes or period. For example, step 14560 issues an alert in step 14570 if three consecutive filling strokes have a dP / dt below 50 mmHg / second. In this case, regardless of the flow metric or minimum dP / dt, the logic proceeds to the blood pump delivery stroke in step 14580 and then returns to start the filling stroke in step 14510.

[0147] Interaction with water purification systems A hemodialysis machine or device (HDD) can be configured to interact with and communicate with a water purification device (WPD) that mixes dialysate and supplies water to the HDD system to sterilize the HDD before and after dialysis treatment. In conventional disclosures (see, for example, U.S. Patent Application Publication 2016 / 0058933), a series of messages and data may be exchanged between the HDD controller and the WPD controller. A more streamlined approach can limit the type of interaction between the two devices and instead rely on pre-programmed or autonomous functions of the WPD. In one example, the WPD may be a steam compression / distillation device. Alternatively or additionally, other water purification devices and methods may be used, such as semipermeable membrane filtration, reverse osmosis, ultraviolet irradiation, charcoal adsorption, or any combination thereof.

[0148] The HDD controller can be configured to send a start signal to the WPD, which represents a command to begin generating ambient water, and the WPD proceeds according to an independently programmed processor. This is a mode typically used when supplying purified water to the HDD for mixing and treatment of dialysate. The HDD controller can also send a hot water start command to the WPD, which represents a command to begin generating hot water according to a pre-programmed process of the WPD. This is a mode typically used to perform the sterilization procedure of the WPD. The lines connecting the WPD and the HDD (the HDD's water supply lines) and the HDD itself can be sterilized using one or more processes programmed into the HDD controller.

[0149] The HDD controller can also instruct the WPD to enter either standby mode or standby state, or idle mode or idle state. In a steam compression / distillation apparatus, the idle state may include pausing the pump or compressor, turning off the heater, closing valves, and deactivating the control loop and water level controller. Standby mode or standby state allows the WPD to produce purified water relatively quickly. Optionally, in a steam / distillation system, this may include filling the purified water system with water, heating the water to a point where purified water production can begin, controlling the vent valve to maintain the low-pressure steam temperature target, and optionally, producing enough water to fill the reservoir, or alternatively, draining any excess water produced. If the WPD is started from an inactive (off) or idle state, the HDD controller can optionally be programmed to send commands early enough to allow the WPD to produce water by the time the HDD expects to receive water (in some cases, this may be about two hours from a cold start or idle mode start, or as little as about ten minutes from standby mode). In most cases, the HDD controller instructs the idle WPD to enter standby mode when the two systems establish communication, or when one or both systems are powered off and then restarted. This cannot happen if an error condition is flagged.

[0150] During water supply, the HDD controller can send a stop signal to the WPD, instructing the WPD to enter a standby state. In this case, the standby state is an autonomous function of the WPD that keeps water generation or purification sufficiently active so that it can supply water based on instructions from the HDD within a relatively short time (for example, within about 10 minutes after a start or resume command is sent from the HDD to the WPD). Among other processes, this may include filling the water purification system with water and heating the water to a point where water purification can be quickly initiated.

[0151] The HDD controller can also send a sterilization start command to the WPD, which is typically scheduled to occur after the end of a dialysis treatment or during the time between treatment sessions with the HDD. In this case, the WPD enters automatic hot water generation mode. In a typical sequence, the HDD first instructs the WPD to transition to water generation mode, and then, once it is notified that the WPD has entered water generation mode, instructs it to transition to sterilization mode. When the water generated by the WPD reaches a predetermined temperature (e.g., 90°C), a signal is transmitted to the HDD controller, and the HDD begins the sterilization procedure of the inlet line. The inlet line includes the flow path within the HDD before the branching point connects the HDD to the drain or the flow path to the HDD's mixing circuit (beyond this branching point, the internal flow path of the HDD can be sterilized by the circulation of programmed hot water or chemical disinfectant without a "closed end"). In this state, all tubing connecting the WPD's output port or output line to the HDD's input port or input line is also sterilized.

[0152] The HDD controller can be programmed to sterilize the WPD-HDD connection lines and flow paths at a predetermined minimum temperature for a predetermined minimum time. For example, the sterilization temperature can be set to 85°C for a minimum time of 35 minutes. The temperature can be measured by a temperature sensor located in the HDD water inlet line. To reduce the number of temperature sensors in the HDD system, the inlet water temperature sensor can also be preferably located in the HDD flow path to monitor the temperature of the sterilizing solution circulating through the HDD flow path during sterilization of the HDD system. The minimum sterilization temperature can be optionally adjusted, taking into account the heat loss before the water reaches the sensor, depending on the distance the incoming water travels before reaching the sensor.

[0153] Figure 68 shows a schematic diagram of the fluid flow path for the hemodialysis system described in a previous application. Section A represents the blood flow path of the system, section B represents the dialysate balancing and dialyzer delivery section, section C represents the dialysate storage, heating, and ultrafiltration section, and section D represents the water inlet and dialysate mixing section. The water inlet line 400 is configured to connect to a water source from the outside. In this embodiment, the water source includes a water purification device (WPD), such as a steam compression / distillation unit. For ease of reference, in this specification, the water inlet line 400 means the entire water line connection between the water purification outlet of the WPD and point 402, where the HDD water inlet line has a valve connection to the internal flow path of the HDD. In practice, this inter-device water line may comprise one or more connectors or valves. However, for sterilization purposes, the water inlet line 400 can be considered to include the entire inter-device water line.

[0154] The internal fluid channels of the WPD and the illustrated HDD can be configured to achieve a thorough and complete sterilization process, but special care must be taken to sterilize the water inlet line and / or inter-device line connecting the WPD to the HDD. Note that the water inlet line 400 has a valve connection 402 to the internal HDD channel, and this inter-device fluid connection (WPD outlet line and HDD inlet line) should be closed off for the purpose of thorough sterilization, either chemically or thermally. This condition is also reflected in the outlet line of the WPD. An HDD dialysate heater can be used to heat water pumped in the reverse direction by one or more dialysate pumps to the HDD inlet line, WPD outlet line, and WPD drain connection, but it may be more efficient for purified hot water (or water containing a suitable chemical disinfectant) to be generated by the WPD and sent to the HDD in the normal forward direction, with the disinfectant discharged to the HDD drain line 404.

[0155] Figure 69 shows a separate diagram of section D of the flow path in the HDD system. A temperature sensor can be placed in line 400, but it functions only to monitor the temperature of the incoming water. For sterilization purposes, the incoming heated water can be sent directly to drain 404, but this flow path depends on the operation of the water pump located in the WPD. Alternatively, a temperature sensor 406 can be placed in internal line 408 connected to water pump 410, which can provide the pumping action necessary to move water through lines 400 and 408. This sensor can also be used to monitor the temperature of the liquid being sterilized in various internal flow paths within the HDD system. In Figure 68, heated liquid from section C can be sent to the flow path in section D via water line 408. The inlet line sterilization channel, incorporating the water pump 410 within the system illustrated in Figure 69 (see also Figure 68), is guided through conductivity / temperature sensors 412 and 414 in the dialysate mixing path, and then bypasses the dialysate tank 416 by closing valve 418 and opening valve 420, thereby leading to the drain line 404. Note that in alternative embodiments, monitoring of the sterilization fluid temperature can be performed using existing temperature sensors (i.e., sensors 412 or 414) already installed for the purpose of mixing the dialysate, without adding a temperature sensor to the water inlet line 400 or 408. In all these cases, either an actively controlled valve or a passive check valve ensures that the sterilization fluid is led to the drain line 404.

[0156] In one embodiment, as shown in Figure 70, the start of the sterilization procedure may first involve an HDD command 450 instructing the WPD to begin normal water generation. Subsequently, the HDD begins priming the flow path with water from the WPD (452). Next, the HDD instructs the WPD to generate water heated to the required sterilization temperature (454). Optionally, the temperature at which the WPD generates heated water is higher than the minimum sterilization temperature specified for the line interconnecting the WPD and the HDD. This is to account for the heat loss of water as it passes through the interconnection line. For example, if the minimum sterilization temperature is 85°C, the WPD may be programmed to generate water at 90°C at its outlet. Optionally, the HDD may be programmed to begin its own hot water generation using an internal heater (e.g., heater 411 shown in Figure 68) (456). This prepares the HDD to perform its own sterilization after the inter-device line 400 has been sterilized and helps maintain a high ambient temperature within the HDD housing to limit heat loss during sterilization of the inter-device line 400. Once both the HDD and the WPD have heated their individual fluid channels to a predetermined temperature, the HDD controller can instruct the WPD to begin supplying heated water from the product outlet line to the inter-device line connecting the WPD to the HDD (inlet line 400) (458).

[0157] The water sterilization temperature may change during the sterilization period. Optionally, the HDD controller can be programmed to track the time it takes for the measured temperature to reach or exceed a minimum sterilization temperature programmed into the controller.

[0158] As shown in Figure 71, optionally, before starting the sterilization counter on the inter-device line 400, the HDD controller initiates control of the HDD internal pump and associated valves to circulate the heated water flowing in from the WPD for a predetermined period of time to completely fill the sterilization channel with hot water (460). In addition to the inter-device line, in one example, this channel may include an internal HDD channel that leads to the dialysate tank 416 but is diverted to the drain 404 by one or more valves 418, 420, and then leads the sterilization water through a water pump 410 in the mixing circuit (see, for example, Figure 69). In one example, the HDD controller directs heated water from the WPD to the HDD drain for about two minutes before starting the inter-device line sterilization counter.

[0159] The HDD controller may be programmed to include a predetermined minimum sterilization temperature (e.g., 78°C). When this temperature is detected by a temperature sensor (e.g., sensor 406, or sensor 412 or 414), the controller starts a sterilization timer 462. When this minimum sterilization temperature is maintained for a predetermined minimum sterilization time (e.g., 35 minutes) (464), the controller may declare that sterilization of the inter-device line 400 is complete. The sterilization timer is updated as long as the detected temperature is above the minimum sterilization temperature (464).

[0160] Optionally, the controller may be programmed to include a timer 466 that accumulates the time during which the detected temperature is below the minimum sterilization temperature but above a predetermined low-temperature threshold (e.g., 70°C). If a predetermined low-temperature timeout value is reached (e.g., 10 minutes to time out the sterilization cycle), the controller may notify the user interface with an alarm and instruct the WPD to pause water production (468). Optionally, the controller may also be programmed to notify the alarm and instruct the WPD to pause water production (468) if the detected temperature is below a predetermined low-temperature threshold (e.g., 70°C).

[0161] If the sterilization of the inter-device line 400 is successful (470), the HDD controller can close the water inlet line valve 402 and instruct the WPD to start the sterilization procedure, thereby initiating the HDD sterilization procedure. If the sterilization of the inter-device line 400 fails, the user is notified and the WPD is instructed to pause water generation (468). In these situations, the HDD controller optionally initiates a repriming procedure for its flow path and resets the sterilization timer to 472. The HDD controller can then wait for user input on whether to retry the sterilization procedure (474). If no retry is requested, the HDD may optionally initiate a service call (476). The controller can be configured to provide the user with appropriate instructions on the user interface or to automatically send appropriate messages to remote servers and service centers via an internet communication link.

[0162] The HDD controller may instruct the WPD to enter a flush mode, in which source water flows into the system and passes through the filters within the system. This is typically performed after filter replacement. If filter replacement (e.g., carbon filter) is instructed, the HDD controller first instructs the WPD to enter an idle state, and then alerts the user on the graphical user interface that the WPD is ready to replace the filter. Once the user instructs the WPD to complete this task, the HDD instructs the WPD to enter a standby state, and then performs the flush mode. The HDD instructs the WPD to return to the standby state upon completion of this task, allowing the water generation state to start quickly at the beginning of treatment. The flush mode may also be instructed before fluid sampling to ensure a more reliable indication of filter quality. It may also be instructed if the WPD system has been idle or in standby for a predetermined period of time.

[0163] Status messages may be transmitted between the Water Layer and the Therapy Layer of the HDD system controller architecture. Exemplary messages that the Water Layer may receive from the WPD may include:

[0164] - Current operating status of WPD - Current WPD identification code or identifier - Date the WPD filter was installed - Do the filters need to be replaced? - Whether communication with WPD has been lost. - Whether WPD is showing an operational error - Whether WPD indicates a fail-safe error - Time since the last sterilization of WPD - Do you need to sterilize the WPD? - Software version installed on the WPD system controller Status messages regarding the operating status of WPD may include one or more of the following:

[0165] -WPD Active (Independent of HDD): By initiating a communication link between the HDD and WPD, the HDD instructs WPD to enter standby mode. -WPD during idle; the product valve is closed.

[0166] -WPD during standby: The product valve is open. -WPD generates room temperature water; product valve is open. - The WPD is waiting for filter replacement; the product valve is closed.

[0167] -WPD flushes the line and filter after filter replacement. - The WPD generates hot water; when the temperature is reached, the product valve opens. -WPD performs sterilization; product valve is closed.

[0168] -WPD generates a water sample for testing (e.g., chloramine test); product valve is closed. -WPD is waiting for user input via GUI to send a test water sample.

[0169] -WPD is in a fail-safe state; the product valve is closed. Preferably, the HDD controller instructs the WPD to remain in standby mode whenever the WPD is not performing another process. If another process (e.g., sterilization) is in progress, the HDD controller waits for this process to complete. Once the WPD enters standby mode, the HDD controller may check whether the WPD should perform a filter flushing process. If it should, the WPD begins the filter flushing process. Also, for example, if the power is cut off before the filter flush is complete after a filter replacement, the HDD may instruct the WPD to perform a filter flushing process.

[0170] Optionally, before starting therapeutic water production, the HDD may be programmed to prompt the user to sample the water produced from the WPD for various contaminants, such as chloramines. The HDD may instruct the WPD to begin the water sampling state. When the WPD indicates that sampling is ready, the HDD alerts the user to collect and test the water sample. If the user indicates that the sample passed the test, the HDD may instruct the WPD to start therapeutic water production. If the user indicates that the sample failed the test, the HDD may optionally instruct the WPD to enter a standby state.

[0171] Errors occurring from the WPD during water generation can be notified to the HHD, which may then instruct the HHD to check the error condition and issue an alert to the user via an interface (e.g., the HDD interface). The WPD controller then waits for instructions from the user to resume water generation or transition to standby mode. Failsafe error conditions typically cause the WPD to stop operating and notify the HDD to begin the retrieval procedure. The technical concepts that can be understood from the above embodiments are described below as an addendum. [Note 1] A manifold adapter configured to connect a pressure distribution manifold to a fluid processing cassette assembly, The housing comprises a first side having a first set of transfer ports configured to connect to the operating output port of the manifold, and a second side on the opposite side having a second set of transfer ports configured to connect to the operating input port of the cassette assembly, The first set of transfer ports includes a first spatial array configured to match the spatial array of the manifold's operational output ports, The second set of transport ports includes a second spatial array configured to match the spatial array of the operating input ports of the cassette assembly, The first spatial array of the transfer port is a manifold adapter, which is different from the second spatial array of the transfer port. [Note 2] The manifold adapter according to Note 1, wherein the first spatial array covers a region of the first side surface of the adapter housing having a first length and a first width, and the second spatial array covers a region of the second side surface of the adapter housing having a second length and a second width, and the second length is greater than the first length such that the housing of the manifold adapter protrudes from the side surface of the manifold. [Note 3] The manifold adapter according to Note 1, wherein the second side of the housing includes an elastomer wiper gasket consisting of a plurality of wiper seals, each of the plurality of wiper seals is associated with a transfer port on the second side of the adapter housing, and the wiper gasket is embedded beneath the upper plate of the adapter housing. [Note 4] A seating device for a cassette having a plug-in side and an opposite mounting side, The cassette mount comprises a fixed frame member connected to a movable cassette mount by a plurality of link mechanisms located on a first side of the cassette mount and a second side opposite the cassette mount, wherein the link mechanisms on the first side of the cassette mount are connected to a first fixed flange of the fixed frame member, and the link mechanisms on the second side of the cassette mount are connected to a second fixed flange of the fixed frame member. Each of the plurality of link mechanisms includes a swing arm having a first end pivotably coupled to a fixed flange and a second end coupled to an elongated slot of the cassette mount. The second end of the swing arm is configured to move along an arc-shaped path to move the cassette mount, The elongated slot restricts the movement of the cassette mount by the swing arm to a linear motion toward or away from the fixed frame member, in a seating device. [Note 5] The seating device according to Note 4, wherein the cassette mount includes a first movable flange and a first rail on the first side of the cassette mount, and a second movable flange and a second rail on the second side of the cassette mount, each movable flange having a surface substantially parallel to the direction of movement of the cassette mount, the elongated slot formed in the movable flange and oriented perpendicular to the direction of movement of the cassette mount, and the first and second rails hold the mounting side of the cassette. [Note 6] The seating device according to Note 5, further comprising a handle assembly pivotably connected to the cassette mount, wherein the cassette mount moves away from the fixed frame member when the handle of the handle assembly moves away from the fixed frame member, and the cassette mount moves toward the fixed frame member when the handle moves toward the fixed frame member. [Note 7] The seating device according to Note 6, wherein the pivot connections of the handle assembly include a first pivot connection of the first handle arm to the first fixed flange, a second pivot connection of the second handle arm to the second fixed flange, a third pivot connection of the first handle arm to a handle swing arm connected to the first movable flange of the cassette mount, and a fourth pivot connection of the second handle arm to a handle swing arm connected to the second movable flange of the cassette mount, wherein the first and third pivot connections and the second and fourth pivot connections are spaced apart from each other on the first and second handle arms. [Note 8] The seating device according to Note 6, comprising a third fixing flange of the fixed frame member, the third fixing flange facing the handle assembly and substantially perpendicular to the first and second fixing flanges, and the handle assembly comprising a spring plunger configured to engage with a hole or recess in the third fixing flange such that the cassette mount is locked in a retracted position when the handle of the handle assembly moves toward the fixed frame member. [Note 9] A method for controlling a pneumatically operated diaphragm pump, The steps include opening a valve that fluidly connects the air pressure source to the working chamber of the diaphragm pump, The steps include monitoring the pressure of one or more gases in the operating chamber of the diaphragm pump, The steps include closing the valve when the pressure in the operating chamber exceeds the target pressure, A method comprising the step of opening the valve when the average magnitude of the monitored pressure is less than the target pressure. [Note 10] The method according to Note 9, further comprising the action of averaging the pressure monitored after the valve has been closed. [Note 11] The method according to Note 10, further comprising the action of setting the average pressure to zero before the valve is closed. [Note 12] The method according to Note 9, wherein the valve is a binary valve. [Note 13] The method according to Note 9, wherein the pressure is monitored by a controller equipped with a pressure sensor fluidly connected to the working chamber. [Note 14] The method according to Note 13, wherein the controller receives pressure information from the pressure sensor and controls the valve using the pressure information. [Note 15] A method for controlling the fluid flow rate of a pneumatically operated diaphragm pump, The first step is to open the valve that fluidly connects the air pressure source to the working chamber of the diaphragm pump, The steps include monitoring the pressure of one or more gases in the operating chamber of the diaphragm pump, A step of marking the time the first valve is open, The steps include closing the valve when the pressure in the operating chamber exceeds the target pressure, The steps include opening the valve when the average magnitude of the monitored pressure falls below the target pressure, A step of detecting the end of the pumping stroke based on the monitored pressure, A step of marking the time of completion of the pump stroke, A method comprising the steps of changing the target pressure based on the difference between a stroke duration and a predetermined target stroke duration, wherein the stroke duration is the difference in time between the end of the pump stroke and the opening of the first valve. [Appendix 16] The method according to Appendix 15, further comprising the step of averaging the pressure monitored after the valve is closed. [Note 17] The method according to Note 16, further comprising the step of setting the average pressure to zero before the valve is closed. [Note 18] The method according to Note 17, wherein the valve is a binary valve. [Note 19] The method according to Note 15, wherein the pressure is monitored by a controller using a pressure sensor fluidly connected to the working chamber. [Appendix 20] The method according to Appendix 19, wherein the controller controls the valve using information from the pressure sensor. [Note 21] A method for controlling a pneumatically operated diaphragm pump, The steps include opening a valve that fluidly connects the air pressure source to the working chamber of the diaphragm pump, The steps include monitoring the pressure of one or more gases in the operating chamber of the diaphragm pump, The steps include closing the valve when the pressure in the operating chamber exceeds the target pressure, A method comprising the steps of opening the valve when the average magnitude of the monitored pressure is less than a target pressure by a predetermined value, wherein the predetermined value changes during the stroke of the diaphragm pump. [Note 22] The method according to Note 21, wherein the predetermined value changes according to the number of valves opened during the stroke. [Note 23] The method according to Note 21, wherein the predetermined value changes depending on whether the diaphragm pump is filled or empty.

Claims

1. A method for controlling a pneumatically operated diaphragm pump, The steps include opening a valve that fluidly connects the air pressure source to the working chamber of the diaphragm pump, The steps include monitoring the pressure of one or more gases in the operating chamber of the diaphragm pump, The steps include closing the valve when the pressure in the operating chamber exceeds the target pressure, A method comprising the step of opening the valve when the average magnitude of the monitored pressure is less than the target pressure.

2. The method according to claim 1, further comprising the operation of averaging the monitored pressure after the valve has been closed.

3. The method according to claim 2, further comprising the action of setting the average pressure to zero before the valve is closed.

4. The method according to claim 1, wherein the valve is a binary valve.

5. The method according to claim 1, wherein the pressure is monitored by a controller equipped with a pressure sensor fluidly connected to the working chamber.

6. The method according to claim 5, wherein the controller receives pressure information from the pressure sensor and controls the valve using the pressure information.

7. A method for controlling the fluid flow rate of a pneumatically operated diaphragm pump, The first step is to open the valve that fluidly connects the air pressure source to the working chamber of the diaphragm pump, The steps include monitoring the pressure of one or more gases in the operating chamber of the diaphragm pump, A step of marking the time the first valve is open, The steps include closing the valve when the pressure in the operating chamber exceeds the target pressure, The steps include opening the valve when the average magnitude of the monitored pressure falls below the target pressure, A step of detecting the end of the pumping stroke based on the monitored pressure, A step of marking the time of completion of the pump stroke, A method comprising the steps of changing the target pressure based on the difference between a stroke duration and a predetermined target stroke duration, wherein the stroke duration is the difference in time between the end of the pump stroke and the opening of the first valve.

8. The method according to claim 7, further comprising the step of averaging the pressure monitored after the valve is closed.

9. The method according to claim 8, further comprising the step of setting the average pressure to zero before the valve is closed.

10. The method according to claim 9, wherein the valve is a binary valve.

11. The method according to claim 7, wherein the pressure is monitored by a controller using a pressure sensor fluidly connected to the working chamber.

12. The method according to claim 11, wherein the controller controls the valve using information from the pressure sensor.

13. A method for controlling a pneumatically operated diaphragm pump, The steps include opening a valve that fluidly connects the air pressure source to the working chamber of the diaphragm pump, The steps include monitoring the pressure of one or more gases in the operating chamber of the diaphragm pump, The steps include closing the valve when the pressure in the operating chamber exceeds the target pressure, A method comprising the steps of opening the valve when the average magnitude of the monitored pressure is less than a target pressure by a predetermined value, wherein the predetermined value changes during the stroke of the diaphragm pump.

14. The method according to claim 13, wherein the predetermined value changes according to the number of valves opened during the stroke.

15. The method according to claim 13, wherein the predetermined value changes depending on whether the diaphragm pump is filled or empty.

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