Flexible impeller pumps and disposable fluid flow circuits incorporating such pumps

A disposable fluid pump is provided with a housing including first and second faces, with a sidewall extending between the first and second faces. The housing defines a chamber, with an inlet and an outlet in fluid communication with the chamber. An impeller is rotatably mounted within the chamber and includes a plurality of flexible vanes. Such a pump may be incorporated into a disposable fluid flow circuit that is adapted to be mounted on a durable hardware for processing a fluid. In such a fluid flow circuit, the fluid pump may be integrated into a cassette of the circuit or, alternatively, the inlet and outlet of the fluid pump may be directly connected to fluid flow conduits of the circuit.

BACKGROUND

Field of the Disclosure

The present subject matter relates to impeller pumps for moving fluid through a fluid flow circuit. More particularly, the present subject matter relates to flexible impeller pumps for use in disposable fluid flow circuits.

Description of Related Art

A variety of systems and methods are known for pumping or otherwise moving fluid through a fluid flow path, with the most preferable method for moving fluid through a fluid flow path depending on a number of factors. For example, extracorporeal processing of bodily fluid (e.g., blood withdrawal and separation or peritoneal dialysis) may involve any of a number of fluid movement techniques and devices. According to one approach, a durable processing system or device is used in combination with a disposable processing set or circuit. The durable processing system typically includes a pump assembly that interacts with one or more of the components of the disposable circuit to draw blood or another bodily fluid from a patient or donor or subject and then move the blood or bodily fluid to another location within the disposable circuit, which may include returning or all of portion of the blood or bodily fluid to the patient or donor or subject.

Frequently, the component of the disposable circuit that interacts with the pump assembly is a molded plastic piece commonly referred to as a cassette. As used herein, the term “cassette” refers to a component of a fluid processing system that includes one or more defined fluid passageways. The cassette is secured to a cassette holder or cassette station of the durable equipment, with a flexible membrane or diaphragm or sheet of the cassette facing the durable equipment. The cassette holder or cassette station typically includes a number of valve actuators that selectively press against the flexible diaphragm for opening and closing valve stations of the cassette, thereby controlling which of the fluid passageways are connected to each other and directing the fluid between any of a number of sources and destinations.

An exemplary cassette and cassette holder are employed by the AMICUS® system sold by Fenwal, Inc. of Lake Zurich, Ill., which is an affiliate of Fresenius Kabi AG of Bad Homburg, Germany. One version of the AMICUS® system is described in greater detail in U.S. Pat. No. 5,868,696, which is hereby incorporated herein by reference. In the AMICUS® system, fluid flow is controlled by a disposable cassette with preformed fluid passages, which interfaces with an array of actuators and sensors located on a panel of the durable hardware. Flexible tubing loops connected to opposing edges of the cassette are received within peristaltic pump stations having rollers that press against the loops and rotate to move fluid through the cassette (and through the other components of the disposable circuit).

According to another approach, a reusable hardware system is configured to be used in combination with a disposable fluid flow circuit omitting a cassette. The Autopheresis-C® system sold by Fenwal, Inc. of Lake Zurich, Ill., which is an affiliate of Fresenius Kabi of Bad Homburg, Germany, is exemplary of such an approach. One version of the Autopheresis-C® system is described in greater detail in U.S. Pat. No. 5,614,106, which is hereby incorporated herein by reference. In such a system, rather than peristaltic pumps engaging tubing loops extending from the edges of a cassette, the disposable fluid flow circuit includes a plurality of flexible tubes or fluid flow conduits that may be associated with peristaltic pumps of the durable hardware, which are actuated to cause fluid flow through the circuit.

SUMMARY

In one aspect, a disposable fluid pump is provided with a housing including first and second faces, with a sidewall extending between the first and second faces. The housing defines a chamber, with an inlet and an outlet in fluid communication with the chamber. An impeller is rotatably mounted within the chamber and includes a plurality of flexible vanes.

In another aspect, a disposable cassette is adapted for incorporation into a disposable fluid flow circuit. The disposable cassette includes a body with a topside, an underside, and an edge wall extending therebetween. The body defines a plurality of fluid flow paths. The cassette also includes a fluid pump associated with the body and including a housing with first and second faces and a sidewall extending therebetween. The housing defines a chamber, with an inlet and an outlet each in fluid communication with the chamber and with a different one of the fluid flow paths defined by the body. The fluid pump further includes an impeller rotatably mounted within the chamber, which includes a plurality of flexible vanes.

In yet another aspect, a disposable fluid flow circuit is adapted for cooperative mounting on a durable hardware for processing a fluid. The disposable fluid flow circuit includes a plurality of fluid flow conduits and a fluid pump. The fluid pump is operable to convey fluid through at least a portion of the fluid flow circuit and includes a housing with first and second faces and a sidewall extending therebetween. The housing defines a chamber, with an inlet and an outlet in fluid communication with the chamber. An impeller is rotatably mounted within the chamber and includes a plurality of flexible vanes.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

The embodiments disclosed herein are for the purpose of providing the required description of the present subject matter. They are only exemplary, and may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting the subject matter as defined in the accompanying claims.

FIG. 1shows an exemplary embodiment of a disposable fluid pump10aof a disposable fluid flow circuit (not illustrated) in operative association with a durable drive unit12of a durable hardware (not illustrated) onto which the fluid flow circuit may be mounted for fluid processing. Several variations of disposable fluid pumps will be described herein (collectively identified by the reference numeral10), being differently configured and/or operating in different ways. It should be understood that the configurations and operative principles of the various fluid pumps described herein may be combined and otherwise modified, with one or more individual aspects of a particular fluid pump being applicable to modify the configuration and/or operation of another one of the fluid pumps described herein. Additionally, to the extent not explicitly described (and not contradicted by explicit disclosure), it should be understood that the components of the various fluid pumps described herein, along with the operation of the individual components and structure and operation of the fluid pump as a whole, are in accordance with the detailed description of a corresponding component of any other fluid pump described herein or of the overall structure and operation of any other fluid pump described herein.

The fluid pump10acomprises a housing14including a first or front face16and a second or rear face18, with a sidewall20extending between the first and second faces16and18. As used herein, the term “face” refers to the surface or surfaces of the housing14through which a rotational axis A of an impeller22positioned within the housing14extends (FIG. 2), while the “sidewall” is the surface or surfaces connecting the “faces” and typically extends in a direction generally parallel to the rotational axis A of the impeller22. In one embodiment, the housing14is formed of a generally rigid, disposable material, with faces16and18that are substantially parallel and a sidewall20that is generally perpendicular to the faces16and18. It should be understood that the configuration of the housing14ofFIG. 1is merely exemplary and that the housing14of a fluid pump10according to the present disclosure may be differently configured.

The housing14defines a cavity or chamber24(FIG. 2), with an inlet26and an outlet28in fluid communication with the chamber24. Each of the inlet26and the outlet28is configured to allow fluid flow between the chamber24of the fluid pump10aand a location positioned externally of the fluid pump10a. For example, a fluid conduit or flexible tubing may be connected to the inlet26to allow the fluid pump10ato draw fluid through the conduit and into the chamber24via the inlet26, as will be described in greater detail. Similarly, a second fluid conduit or flexible tubing or the like may be connected to the outlet28to allow the fluid pump10ato expel or convey fluid out of the chamber24and into the second conduit via the outlet28, as will be described in greater detail.

In the embodiment ofFIGS. 1 and 2, each of the inlet26and outlet28extends through the sidewall20to allow fluid flow between the chamber24and a position that is external to the chamber24. In other embodiments, one or both of the inlet26and outlet28may extend from the chamber24to one of the housing faces16,18. Regardless of the exact position of the inlet26and the outlet28, it may be advantageous for them to be positioned apart from each other, rather than being directly adjacent to each other. For example, in the embodiment ofFIGS. 1 and 2, the inlet26and outlet28are positioned approximately 90° apart about the rotational axis A of the impeller22mounted within the chamber24. In other embodiments in which the inlet26and outlet28each extend through the sidewall22of the housing14, the inlet26and outlet28may be positioned more or less than 90° apart about the rotational axis A.

FIG. 2shows an exemplary impeller22that may be at least partially positioned within the chamber24defined by the pump housing14. To that end, it may be advantageous for the housing14to be provided in two or more pieces, which allows the impeller22to be positioned in the portion of the chamber24defined by one of the housing pieces while the fluid pump10ais in a partially assembled condition (as inFIG. 2), with additional pieces of the housing14being subsequently secured to the first housing piece to fully define the housing14and at least partially enclose the impeller22within the chamber24(FIG. 1).

The impeller22is rotatably mounted within the chamber24to allow the impeller22to rotate about a rotational axis A, which may coincide with the central axis or midpoint of the impeller22. The impeller22includes a plurality of flexible vanes or blades30. In the embodiment ofFIG. 2, the impeller22includes six substantially identical vanes30, but it is within the scope of the present disclosure for an impeller to include more or fewer than six vanes (see the fluid pump10bofFIG. 4, for example) and/or for the individual vanes of an impeller to be differently configured than the individual vanes30ofFIG. 2. It is also within the scope of the present disclosure for two or more vanes of a particular impeller to be differently configured from each other. Preferably, each vane30is equally spaced from each adjacent vane30(e.g., with there being a 60° separation between adjacent vanes of an impeller having six vanes), but it is also within the scope of the present disclosure for the angle between adjacent vanes of a single impeller to vary.

Each vane30is preferably sufficiently elongated so as to contact the perimeter wall32of the chamber24(which is defined by the sidewall20of housing14in the embodiment ofFIGS. 1 and 2). Thus, as the impeller22rotates within the chamber24, a portion of each vane30slides along the perimeter wall32of the chamber24. Preferably, the impeller22and each vane30is also sufficiently tall or thick to extend between the upper and lower ends of the chamber24(which may be defined by the housing faces16and18), such that fluid positioned between a pair of adjacent vanes30cannot move beyond or around either vane and must remain between the vanes until exiting the chamber24via the outlet28(as will be described).

As will be described in greater detail, the chamber24is preferably non-circular, with a non-uniform diameter, in which case the distance between the perimeter wall32and the rotational axis A varies at different angular positions about the rotational axis A. By providing vanes30that are formed of a flexible material or materials, the shape of each vane30may resiliently deform during rotation of the impeller22to occupy the appropriate space between the rotational axis A and the portion of the perimeter wall32contacted by the vane30. Thus, at angular positions at which the perimeter wall32is spaced relatively far from the rotational axis A, a vane30may be in an unflexed or less flexed condition (see vanes30a-30dofFIG. 3), whereas a vane may be in a flexed or more flexed condition (see vane30eofFIG. 3) at angular positions at which the perimeter wall32is spaced relatively close to the rotational axis A. When transitioning between its least (or unflexed) and most flexed conditions, each vane30passes through partially flexed conditions, with the instantaneous shape and degree of flexure of the vane30depending upon its angular position (which is determinative of the distance between the rotational axis A and the perimeter wall32).

Turning back now to the chamber24illustrated inFIG. 2, a generally crescent-shaped surface or structure or formation34is associated with a portion of the sidewall20. Due to the presence of the generally crescent-shaped formation34(which may be integrally formed with the housing14or separated provided and positioned within the chamber24), the perimeter wall32has a non-uniform radius about the rotational axis A of the impeller22. In the embodiment ofFIG. 2, the housing sidewall20defines a perimeter wall32and chamber24with a high-radius arc or portion36and a low-radius arc or portion38. The high- and low-radius portions38and36are separated by the inlet and outlet26and28, with the high-radius portion36having a greater angular extent (approximately 270°) than the low-radius portion38(approximately 90°). In the high-radius portion36, the perimeter wall32may be substantially concentric with the rotational axis A of the impeller22or, stated differently, have an at least substantially uniform radius from the rotational axis A. In the illustrated low-radius portion38(which coincides with the generally crescent-shaped formation34), the perimeter wall32has a radius (which may be either uniform or non-uniform) that is preferably no greater than the radius of the perimeter wall32in the high-radius portion36. In the illustrated embodiment, the radius of the perimeter wall32at the ends of the low-radius portion38may be substantially equal to the radius of the perimeter wall32in the high-radius portion36(i.e., at the transition points between the high- and low-radius portions36and38), while the radius of perimeter wall32is smaller at all other points of the low-radius portion38. In other embodiments, the perimeter wall32may have some other profile, including a non-uniform radius in the high-radius portion and/or high- and low-radius portions that occupy different angular extents than the high- and low-radius portions36and38ofFIG. 2.

The varying radius of the perimeter wall32and the ability of the vanes30to flex allows for fluid flow into, through, and out of the chamber24. The inlet26and outlet28are positioned at the transition points between the high- and low-radius portions36and38of the perimeter wall32. At these transition points, a vane30will be forced to flex from a less flexed condition to a more flexed condition (when being rotated from the high-radius portion36of the chamber24into the low-radius portion38) or from a more flexed condition to a less flexed condition (when being rotated from the low-radius portion38of the chamber24into the high-radius portion36). Changing the configuration of a vane30affects the volume of the space S (FIG. 3) between that vane30and its trailing vane30(i.e., the vane30that rotates through a transition point immediately after the vane30that has just been rotated through the transition point). When a vane30is rotated into the low-radius portion38(i.e., at the transition point that coincides with the position of the outlet28), it will move to a more flexed condition that places it closer to its trailing vane30, thereby decreasing the volume of the space S therebetween. By decreasing the volume of this space S at the outlet28, the two vanes30force the fluid within the space S therebetween to move out of the space S, exiting the chamber24via the outlet28. Conversely, when a vane30is rotated into the high-radius portion36(i.e., at the transition pint that coincides with the position of the inlet26), it will move to a less flexed condition that places it farther from its trailing vane30, thereby increasing the volume of the space S therebetween. By increasing the volume of this space S at the inlet26, the two vanes30create a vacuum, which draws fluid through the inlet26and into the space S.

Accordingly, due to the flexibility of the impeller vanes30and the configuration of the chamber24, rotation of the impeller22within the chamber24draws fluid into the chamber24via the inlet26, transports the fluid through the chamber24from the inlet26to the outlet28between an adjacent pair of rotating vanes30, and then expels the fluid from the chamber24via the outlet28. The rate at which fluid is pumped into and out of the fluid pump10aand/or the volume of fluid drawn into and expelled from the chamber24at each stroke (which may be defined as the moment at which the configuration of a vane30changes upon moving through a transition point) may be controlled in part by selection of a suitably configured fluid pump prior to beginning a fluid processing procedure. Once such a procedure has begun, the rate of rotation of the impeller22may be varied to change the volumetric flow rate of fluid through the fluid pump10a. It should be understood that reversing the rotational direction of the impeller22reverses the flow of fluid through the fluid pump10a, with fluid entering the chamber24via the outlet28and exiting the chamber26via the inlet26. The chamber24may be either symmetrically configured or asymmetrically configured, depending on whether it is preferred for the nature of fluid flow through the fluid pump10ato be the same in both directions or to be direction-dependent.

As for the mechanism or device that causes rotation of the impeller22, its structure may vary without departing from the scope of the present disclosure. In the embodiment ofFIGS. 1 and 2, the impeller22includes a rigid hub40(FIG. 2), which may be formed of a material that is less flexible than the vanes30(e.g., a substantially rigid plastic or metallic material). The rigid hub40is a central component of the impeller22, with the vanes30extending outwardly from the rigid hub40. When the impeller22is mounted within the housing chamber24, the rigid hub40may be positioned at and define the rotational axis A.

The rigid hub40ofFIG. 2includes a shaft portion42that extends outside of the chamber24, through an opening defined in one of the housing faces16,18. This same type of rigid hub40and shaft portion42is employed in the embodiment ofFIGS. 5 and 6and in the embodiment ofFIGS. 7 and 8, which better illustrate a housing face18having an opening44through which the shaft portion42of the rigid hub40extends. The disposable fluid pump10cofFIGS. 5 and 6and the disposable fluid pump10dofFIGS. 7 and 8may be provided in accordance with the preceding description of the disposable fluid pump10aofFIGS. 1-3, with variations in the shape of the housing14, the location of the inlet and outlet26and28(which are parallel, rather than being aligned or coaxial), and the shape of the impeller22. Otherwise, the disposable fluid pump10cofFIGS. 5 and 6and the disposable fluid pump10dofFIGS. 7 and 8(along with the other disposable fluid pumps described herein, unless shown and/or stated to the contrary) are configured and operate as described above with respect to the embodiment ofFIGS. 1-3.

The shaft portion42may be variously configured (e.g., with a circular profile or cross-sectional shape, as inFIG. 2, or with a non-circular profile or cross-sectional shape, as inFIG. 6) that is received by a mating socket (not illustrated) of a durable drive unit12(FIG. 1). When all or a portion of the shaft portion42positioned outside of the housing14is received by the socket of the drive unit12, a motor of the drive unit12may be operated to rotate the socket, which in turn rotates the shaft portion42and, thus, the impeller22within the fluid pump housing14. Accordingly, as described above, the operation of the motor of the drive unit12may be varied to vary the volumetric flow rate of fluid through the fluid pump10.

Alternatively, the positions of the shaft portion and the socket may be reversed, with the rigid hub40of the impeller22defining a socket and the drive unit12including a shaft that is at least partially received by the socket. For example,FIG. 9illustrates a disposable fluid pump10ein which the rigid hub40of the impeller22defines a socket46that is accessible through an opening44in one of the housing faces18. A seal48(e.g., an O-ring) may be positioned between the rigid hub40and the opening44of the housing face18to ensure a fluid-tight relationship while allowing rotation of the impeller22within the chamber24. A similar seal48may also be employed in embodiments in which the rigid hub40of the impeller22includes a shaft portion42. The durable drive unit12ofFIG. 9includes a shaft50that is at least partially received by the socket46of the rigid hub40when the fluid pump10ehas been mounted to the drive unit12. The profile or cross-sectional shape of the socket46preferably matches or is complementary to the profile or cross-sectional shape of the mating shaft50, such that rotation of the shaft50(by operation of a motor of the drive unit12) causes rotation of the impeller22within the chamber24of the fluid pump10e.

The disposable fluid pump10fofFIGS. 10 and 11is a variation of the fluid pump10eofFIG. 9. The disposable fluid pump10fofFIGS. 10 and 11is substantially identical to the fluid pump10eofFIG. 9, except for the orientation of the inlet26and outlet28. In the embodiment ofFIG. 9(as in the embodiments ofFIGS. 1-8), the inlet26and outlet28are in the same plane as the impeller22and chamber24(which plane is substantially perpendicular to the rotational axis A). In contrast, in the embodiment ofFIGS. 10 and 11, the housing14has an enlarged or extended sidewall20, which increases the separation between the housing faces16and18without necessarily increasing the height of the chamber24. By providing extra space between the housing faces16and18, the inlet26and outlet28may each have not only a horizontal section (as in the embodiments ofFIGS. 1-8), but also a vertical section that extends in a direction substantially parallel to the rotational axis A. By employing a vertical section that opens into the chamber24, the inlet26and outlet28ofFIGS. 10 and 11extend through the sidewall20in a different plane than the plane that is occupied by the impeller22and the chamber24.

A fluid pump10fconfigured as inFIGS. 10 and 11may be advantageous if the fluid pump10fis to be partially received within a cavity or pocket of the associated drive unit, as making the inlet26and outlet28accessible in a different plane than the impeller22and chamber24may make it easier to connect the inlet26and outlet28to an external fluid flow path. It should be understood that the particular configuration of the inlet26and outlet28ofFIGS. 10 and 11is merely exemplary and that either or both may be differently configured without departing from the scope of the present disclosure. For example, rather than an inlet26or outlet28having horizontal and vertical sections that are substantially perpendicular to each other, the inlet26and/or outlet28could have an angled or diagonal section and/or a curved section or be otherwise configured in a way that makes the inlet26and/or outlet28accessible through the sidewall20in a different plane than one in which the impeller22and chamber24are present. In another variation, rather than extending between the chamber24and the sidewall20, the inlet26and/or the outlet28may extend between the chamber24and one of the faces16,18of the housing14, with both extending through the same housing face16,18, one extending through the first face16and the other through the second face18, or one extending through one of the faces16,18and the other through the housing sidewall20.

Turning back now to the mechanism or device that causes rotation of the impeller22, whileFIGS. 1-11illustrate a physical interconnection between a shaft42,50and socket46of the impeller22and the drive unit12, other approaches are also contemplated by the present disclosure. For example, in one embodiment, the impeller22includes a magnetized portion or a portion formed of a ferromagnetic material. When used herein, the term “magnetized” or “magnetic” refers to either a substance or component that generates a magnetic field (e.g., a permanent magnet), while the term “ferromagnetic” refers to a material or substance or component that is attracted to a magnet when within the magnetic field generated by a magnetized member. The exact material composition of the magnetized or ferromagnetic portion of the impeller22may vary without departing from the scope of the present disclosure, being formed of iron or some other magnetizable substance or substances. It may be advantageous for all or a portion of the rigid hub40of the impeller22to be magnetized or formed of a ferromagnetic material, but it is also within the scope of the present disclosure for some other portion or portions of the impeller22to be magnetized or formed of a ferromagnetic material.

In embodiments in which the impeller22includes a magnetized or ferromagnetic portion, the drive unit12may also include a magnetized or ferromagnetic portion, which interacts with the magnetized or ferromagnetic portion of the impeller22. In one embodiment, only one of the impeller22and the drive unit12includes a magnetized portion, while the other includes a portion formed of a ferromagnetic material. In another embodiment, both of the impeller22and the drive unit12include magnetized portions that are attracted to each other. With the impeller22and drive unit12magnetically coupled, the drive unit12may vary the magnetic field in the vicinity of the impeller22to cause the impeller22to rotate about the rotational axis A under the power of magnetism. If the impeller22is configured to interact with the drive unit12via magnetism, it may be preferred for the other components of the fluid pump10to be configured so as to be unaffected by the magnetized portion or portions of the impeller22and/or drive unit12. For example, the fluid pump housing14may be formed of a plastic material that is neither attracted to nor repelled by a magnet in its presence.

By employing magnetism to rotate the impeller22within the chamber24, it is possible to provide a pair of housing faces16and18that omit an opening44(to accommodate a shaft42,50of the impeller22or drive unit12). However, it is also within the scope of the present disclosure to employ magnetism in combination with a fluid pump10configured as in any ofFIGS. 1-11(i.e., with one of the impeller22and the drive unit12including a shaft42,50that extends through an opening44in one of the housing faces16,18to be at least partially received within a socket46of the other). In such embodiments, rather than relying upon a complementary, mating relationship between the shaft42,50and socket46(or in combination with such a configuration), the socket46or shaft42of the impeller22is effectively held and rotated by magnetism applied via the matching portion of the drive unit12.

Any of the fluid pumps described herein may be incorporated into disposable fluid flow circuits of the type having a plurality of components fluidly connected by fluid flow conduits (e.g., flexible plastic tubing).FIG. 12shows an exemplary embodiment of a disposable fluid flow circuit52incorporating at least one disposable fluid pump10, which may be used in combination with durable hardware54of the type shown inFIG. 13.

The illustrated fluid flow circuit52is a “two needle” system, which includes a pair of source access devices56and58(e.g., phlebotomy needles) for fluidly connecting a fluid source with the fluid flow circuit52. The source access devices56and58are connected by tubing to a left cassette60A, which will be described in greater detail herein. One of the source access devices56is used to draw fluid from the fluid source into the fluid flow circuit52, while the other source access device58is used to return fluid to the fluid source. Various other access devices62may be connected to other conduits of the fluid flow circuit52to access containers from which fluid may be drawn (e.g., an anticoagulant fluid) and/or into which fluid may be conveyed (e.g., a separated fluid component). Other conduits of the fluid flow circuit52provide fluid communication with additional components of the fluid flow circuit52, such as middle and right cassettes60B and60C and a processing chamber64. The fluid flow circuit52ofFIG. 12is configured for use in separating blood into two or more components, but it should be understood that fluid flow circuits according to the present disclosure may be used for other purposes, in which case they may be differently configured and include different components in fluid communication with each other via the various conduits of the fluid flow circuit.

Each of the disposable cassettes (collectively referred to using the reference number60) includes a body66(which may be a rigid, molded component) with a topside68, an underside70, and an edge wall72extending between the topside68and the underside70. The body66defines a plurality of fluid flow paths74, with fluid flow through the various fluid flow paths74being controlled by selectively actuating valve stations76also defined by the cassette body66. The body66may define other structures or cavities, such as one or more sensor stations, which may be monitored to assess various characteristics of fluid flow through the cassette60. The topside68and underside70may comprise covers or lids that seal the cavities of the body66from the outside environment, with the topside68being formed of a generally rigid material and the underside70comprising a flexible membrane or diaphragm in one embodiment. The edge wall72may comprise a formed perimeter edge of the cassette body66and, thus, be formed of a generally rigid material.

As shown inFIG. 12, at least one of the cassettes60may have a fluid pump10associated therewith and operable to move fluid through the fluid flow paths74of the cassette60. In the illustrated embodiment, the three cassettes60are identical, with each having a pair of fluid pumps10, but it is within the scope of the present disclosure for a single cassette to include only one associated fluid pump10or more than two fluid pumps10and/or for two cassettes of a single fluid flow circuit to be differently configured.

In the embodiment ofFIG. 12, each fluid pump10is associated with the edge wall72of the associated cassette60, with the inlet26and outlet28of each fluid pump10extending through the sidewall20of the fluid pump10. In the embodiment ofFIG. 12, the two fluid pumps10of a particular cassette60are associated with opposing ends of the edge wall72, but it is within the scope of the present disclosure for a cassette60to be provided with a plurality of fluid pumps10associated with the same end of the edge wall72or with adjacent ends of the edge wall72. Furthermore, it is also within the scope of the present disclosure for a fluid pump to be associated with the topside68or underside70of the cassette60if one or both of the inlet26and outlet28extend from the chamber24to one of the housing faces16,18.

In the embodiment ofFIG. 12, a plurality of fluid flow paths74of the cassette60extend through the edge wall72of the cassette60, with each of the inlet26and outlet28of each fluid pump10opening into a different one of these fluid flow paths74. The housing14of the fluid pump10may be an integrally formed portion of the cassette body66, in which case the inlet/outlet and associate fluid flow path define two sections of a common channel. Alternatively, the fluid pump10may be separately provided and secured to the cassette60, in which case the inlet26and outlet28are configured so as to be in alignment with the associated fluid flow path74of the cassette60when the fluid pump10has been secured to the cassette60(e.g., by an adhesive or the like).

The durable hardware54(FIG. 13) includes a surface or station78that may be accessed to place each fluid pump10of a separate fluid processing cassette60into operative engagement with an associated drive unit12of the hardware54. The surface or station78may be referred to as a “cassette holder” and take any of a number of forms, such as a horizontal or inclined surface or panel onto which a cassette60may be placed and then held in place by clamps or clips or the like. In other embodiments, the cassette holder may be a vertical surface with a door or cover hingedly attached thereto. The door may be opened to place a cassette60against the vertical surface, with the door then being closed to hold the cassette60in place against the vertical surface. Any of a number of other configurations of a cassette holder are also possible and within the scope of the present disclosure. The exact configuration of the cassette holder depends on the configuration of the associated cassette, as the two are configured to form a matched pair, with the number and location of the valve actuators, sensor actuators, and drive units of the cassette holder corresponding to the number and location of the valve stations, sensor stations, and fluid pumps of the cassette. As described previously, the underside70of the cassette60may comprise a flexible diaphragm that is acted upon by the valve actuators and sensors of the cassette holder78to direct and monitor the flow of fluid through the cassette60during use. A more detailed description of the configuration and operation of a suitable cassette body66and cassette holder78may be found in U.S. Pat. No. 5,868,696.

In use, the disposable fluid flow circuit52is mounted to the durable hardware54, with the cassettes60mounted to the appropriate cassette holders78so as to put the fluid pumps10in registration with the corresponding drive units12of the durable hardware54. Under the command of a system controller, the durable hardware54selectively operates the drive units12to actuate the fluid pumps10(as described above) to cause fluid flow through the fluid flow paths74of the cassettes60and through the conduits of the fluid flow circuit52. The system controller also operates the valve actuators and sensors of the cassette holders78to interact with the corresponding valve and sensor stations of the cassette60to direct the flow of fluid through the cassettes60and monitor the flow of fluid through the fluid flow paths74, along with controlling the other components of the durable hardware54to carry out a fluid processing procedure (e.g., commanding a centrifuge to rotate the processing chamber64of the fluid flow circuit52to separate fluid into its constituents).

FIG. 14shows another embodiment of an exemplary disposable fluid flow circuit80incorporating at least one disposable fluid pump10, which may be used in combination with durable hardware82of the type shown inFIG. 15. Other than the fluid flow circuit80ofFIG. 14being a “single needle” system (in contrast to the “two needle” system ofFIG. 12), the principal difference between the fluid flow circuit52ofFIG. 12and the fluid flow circuit80ofFIG. 14is that the fluid flow circuit80ofFIG. 14omits cassettes. Instead, in the fluid flow circuit80ofFIG. 14, the fluid flow pumps10are directly connected to the conduits84of the fluid flow circuit80. In particular, a different fluid conduit84may be connected to each of the inlet26and outlet28of a fluid pump10. For example, if the conduits84are provided as flexible tubing, then the end of a conduit84may be inserted within and secured to one of the inlet26and outlet28of a fluid pump10during assembly of the fluid flow circuit80. Other methods of securing a fluid conduit84to the inlet26or outlet28of a fluid pump10(e.g., using a luer connector) may also be employed without departing from the scope of the present disclosure.

In use, the disposable fluid flow circuit80is mounted to the durable hardware82, with the fluid pumps10in registration with the corresponding drive units12of the durable hardware82. The other components of the fluid flow circuit80(e.g., a processing chamber86) are associated with the corresponding components of the durable hardware82. Under the command of a system controller, the durable hardware82selectively operates the drive units12to actuate the fluid pumps10to cause fluid flow through the fluid conduits84of the fluid flow circuit80. The system controller also operates valves or clamps88of the durable hardware82(which may each accommodate a different conduit84of the fluid flow circuit80) to properly direct the flow of fluid through the fluid flow circuit80, along with controlling the other components of the durable hardware82to carry out a fluid processing procedure (e.g., commanding a rotor90to rotate a component of the processing chamber86of the fluid flow circuit80to separate fluid into its constituents).

Aspects of the present subject matter described above may be beneficial alone or in combination with one or more other aspects. Without limiting the foregoing description, in accordance with one aspect of the subject matter herein, there is provided a disposable fluid pump including a housing including first and second faces, with a sidewall extending therebetween. The housing defines a chamber and an inlet and outlet in fluid communication with the chamber. An impeller is rotatably mounted within the chamber and includes a plurality of flexible vanes.

In accordance with another aspect which may be used or combined with the immediately preceding aspect, the chamber has a non-uniform diameter.

In accordance with another aspect which may be used or combined with any of the preceding aspects, at least one of the inlet and outlet extends from the chamber to the sidewall of the housing.

In accordance with another aspect which may be used or combined with the immediately preceding aspect, the inlet and outlet extend from the chamber to the sidewall of the housing.

In accordance with another aspect which may be used or combined with any of the preceding aspects, the chamber and impeller are present in a plane, with at least one of the inlet and outlet extending from the chamber to the sidewall at a location within the same plane in which the chamber and the impeller are present.

In accordance with another aspect which may be used or combined with any of the first through fourth aspects, the chamber and impeller are present in a plane, with at least one of the inlet and outlet extending from the chamber to the sidewall at a location in a different plane than the same plane in which the chamber and the impeller are present.

In accordance with another aspect which may be used or combined with any of the preceding aspects, one of the first and second faces of the housing defines an opening. The impeller includes a rigid hub associated with the flexible vanes and defining a socket accessible through the opening and configured to receive a shaft for rotation of the impeller within the chamber.

In accordance with another aspect which may be used or combined with any of the first through sixth aspects, the impeller includes a rigid hub associated with the flexible vanes and defining a shaft portion. One of the first and second faces of the housing defines an opening through which the shaft portion of the rigid hub extends.

In accordance with another aspect which may be used or combined with any of the first through sixth aspects, the impeller includes a magnetized portion or a portion formed of a ferromagnetic material.

In accordance with another aspect, there is provided a disposable cassette adapted for incorporation into a disposable fluid flow circuit. The disposable cassette includes body having a topside, an underside, and an edge wall extending therebetween. The body defines a plurality of fluid flow paths. A fluid pump is associated with the body and includes a housing having first and second faces and a sidewall extending therebetween. The housing defines a chamber and an inlet and an outlet each in fluid communication with the chamber and with a different one of the fluid flow paths defined by the body of the cassette. An impeller is rotatably mounted within the chamber and includes a plurality of flexible vanes.

In accordance with another aspect which may be used or combined with the immediately preceding aspect, the housing of the fluid pump comprises an integrally formed portion of the body.

In accordance with another aspect which may be used or combined with any of the preceding two aspects, the chamber has a non-uniform diameter.

In accordance with another aspect which may be used or combined with any of the preceding three aspects, at least one of the inlet and outlet extends from the chamber to the sidewall of the housing.

In accordance with another aspect which may be used or combined with the immediately preceding aspect, the inlet and outlet extend from the chamber to the sidewall of the housing and are in fluid communication with the fluid flow paths defined by the body through the edge wall of the body.

In accordance with another aspect which may be used or combined with any of the preceding five aspects, the chamber and impeller are present in a plane. At least one of the inlet and outlet is in fluid communication with the fluid flow paths at a location within the same plane in which the chamber and the impeller are present.

In accordance with another aspect which may be used or combined with any of the tenth through fourteenth aspects, the chamber and the impeller are present in a plane. At least one of the inlet and outlet is in fluid communication with the fluid flow paths at a location in a different plane than the plane in which the chamber and the impeller are present.

In accordance with another aspect which may be used or combined with any of the preceding seven aspects, one of the first and second faces of the housing defines an opening. The impeller includes a rigid hub associated with the flexible vanes and defining a socket accessible through the opening and configured to receive a shaft for rotation of the impeller within the chamber.

In accordance with another aspect which may be used or combined with any of the tenth through sixteenth aspects, the impeller includes a rigid hub associated with the flexible vanes and defining a shaft portion. One of the first and second faces of the housing defines an opening through which the shaft portion of the rigid hub extends.

In accordance with another aspect which may be used or combined with any of the tenth through sixteenth aspects, the impeller includes a magnetized portion or a portion formed of a ferromagnetic material.

In accordance with another aspect, there is provided a disposable fluid flow circuit adapted for cooperative mounting on a durable hardware for processing a fluid. The disposable fluid flow circuit includes a plurality of fluid flow conduits and a fluid pump operable to convey fluid through at least a portion of the fluid flow circuit. The fluid pump includes a housing having first and second faces and a sidewall extending therebetween. The housing defines a chamber and an inlet and an outlet each in fluid communication with the chamber. An impeller is rotatably mounted within the chamber and includes a plurality of flexible vanes.

In accordance with another aspect which may be used or combined with the immediately preceding aspect, the chamber has a non-uniform diameter.

In accordance with another aspect which may be used or combined with any of the preceding two aspects, at least one of the inlet and outlet extends from the chamber to the sidewall of the housing.

In accordance with another aspect which may be used or combined with the immediately preceding aspect, the inlet and outlet extend from the chamber to the sidewall of the housing.

In accordance with another aspect which may be used or combined with any of the preceding four aspects, the chamber and the impeller are present in a plane. At least one of the inlet and outlet extends from the chamber to the sidewall at a location within the same plane in which the chamber and the impeller are present.

In accordance with another aspect which may be used or combined with any of the twentieth through twenty-third aspects, the chamber and the impeller are present in a plane. At least one of the inlet and outlet extends from the chamber to the sidewall at a location in a different plane than the plane in which the chamber and the impeller are present.

In accordance with another aspect which may be used or combined with any of the preceding six aspects, a cassette is connected to at least one of the fluid flow conduits and includes a body comprising a topside, an underside, and an edge wall extending therebetween. The body defines a plurality of fluid flow paths. The housing of the fluid pump is an integrally formed portion of the body, and the inlet and outlet of the fluid pump are in fluid communication with different fluid flow paths defined by the body through the edge wall of the body.

In accordance with another aspect which may be used or combined with any of the twentieth through twenty-fifth aspects, different fluid flow conduits are connected to the inlet and outlet through the sidewall of the housing.

In accordance with another aspect which may be used or combined with any of the preceding eight aspects, one of the first and second faces of the housing defines an opening. The impeller includes a rigid hub associated with the flexible vanes and defining a socket accessible through the opening and configured to receive a shaft for rotation of the impeller within the chamber.

In accordance with another aspect which may be used or combined with any of the twentieth through twenty-seventh aspects, the impeller includes a rigid hub associated with the flexible vanes and defining a shaft portion. One of the first and second faces of the housing defines an opening through which the shaft portion of the rigid hub extends.

In accordance with another aspect which may be used or combined with any of the twentieth through twenty-seventh aspects, the impeller includes a magnetized portion or a portion formed of a ferromagnetic material.