Fluid flow cassette with pressure actuated pump and valve stations

• US 6,481,980 B1
• Filed: 09/03/1999
• Issued: 11/19/2002
• Est. Priority Date: 09/03/1999
• Status: Expired due to Term

• Current Assignee: Fenwal Incorporated (Fresenius SE & Co. KGaA)
• Original Assignee: Baxter International Inc.
• Inventors: Westberg, Tom, Vandlik, Mark R
• Primary Examiner(s): Thorpe, Timothy S.
• Assistant Examiner(s): Rodriguez, William H
• Application Number:
  US09/389,797
• Time in Patent Office: 1,173 Days
• Field of Search: 417/313, 417/477, 417/63, 210/745, 422/44, 137/881, 494/37, 384/138, 554/82, 555/03
• US Class Current: 417/313
• CPC Class Codes: A61M 1/30 Single needle dialysis ; Reciprocating systems, alternately withdrawing blood from and returning it to the patient, e.g. single-lumen-needle dialysis or single needle systems for hemofiltration or pheresis
• CPC Class Codes: A61M 1/302 having a reservoir for withdrawn untreated blood
• CPC Class Codes: A61M 1/303 having a reservoir for treated blood to be returned
• CPC Class Codes: A61M 1/308 Volume control, e.g. with open or flexible containers, by counting the number of pump revolutions, weighing
• CPC Class Codes: A61M 1/362227 the interface providing means for actuating on functional elements of the cassette, e.g. plungers
• CPC Class Codes: A61M 1/36225 with blood pumping means or components thereof
• CPC Class Codes: A61M 1/362261 at least one cassette surface or portion thereof being flexible, e.g. the cassette having a rigid base portion with preformed channels and being covered with a foil
• CPC Class Codes: A61M 1/362262 Details of incorporated reservoirs
• CPC Class Codes: A61M 1/362264 the filter being a blood filter
• CPC Class Codes: A61M 1/362265 Details of valves
• CPC Class Codes: A61M 1/362266 Means for adding solutions or substances to the blood
• CPC Class Codes: A61M 1/3696 with means for adding or withdrawing liquid substances during the centrifugation, e.g. continuous centrifugation
• CPC Class Codes: A61M 2205/128 with incorporated valves
• CPC Class Codes: A61M 2205/331 used as turbidity change detectors, e.g. for priming-blood or plasma-hemoglubine-interface detection
• CPC Class Codes: A61M 2205/3393 by weighing the reservoir
• CPC Class Codes: A61M 60/109 incorporated within extracorporeal blood circuits or systems
• CPC Class Codes: A61M 60/113 in other functional devices, e.g. dialysers or heart-lung machines
• CPC Class Codes: A61M 60/36 for specific blood treatment; for specific therapy
• CPC Class Codes: A61M 60/43 using vacuum at the blood pump, e.g. to accelerate filling
• CPC Class Codes: A61M 60/847 arranged in a cassette
• CPC Class Codes: A61M 60/851 : Valves
• CPC Class Codes: A61M 60/892 : Active valves, i.e. actuated by an external force
• CPC Class Codes: A61M 60/894 : Passive valves, i.e. valves actuated by the blood
• CPC Class Codes: F04B 13/02 : of two or more fluids at the same time
• CPC Class Codes: F04B 2205/09 : Flow through the pump
• CPC Class Codes: F04B 43/026 : each plate-like pumping flexible member working in its own pumping chamber
• CPC Class Codes: F04B 49/065 : and making use of computers
• CPC Class Codes: Y10T 137/87861 : Spring coaxial with valve

Abstract

A cassette for directing fluid flow, comprising a body and a valve chamber formed in the body, provides a centralized, programmable, and integrated platform to carry out diverse and coordinated pumping and valving functions, e.g., such as required for blood processing.

Claims

1. A cassette for directing fluid flow comprising

a body,

a valve chamber formed in the body comprising a peripheral edge and an interior surface adjoining and recessed below the peripheral edge forming a well, the interior surface extending from the peripheral edge along a plane,

a recess formed in the interior surface away from the peripheral edge and extending below the plane of the interior surface,

a valve port in the recess, whereby the recess comprises a recessed valve seat peripherally surrounding the valve port, and

a flexible diaphragm resting on the peripheral edge of the valve chamber responsive to an applied negative pressure for flexure out of the recessed valve seat to open the valve port and responsive to an applied positive pressure for flexure into the recessed valve seat below the plane of the interior surface to close the valve port.

2. A cassette according to claim 1

wherein the valve port includes a terminus that the flexible diaphragm contacts when flexed into the recessed valve seat, and wherein the terminus lays in a plane that is generally coplanar with the plane of the interior surface.

3. A cassette according to claim 1

further including at least one pump chamber formed in the body comprising a recessed wall forming a well and a pump port in the well, and

a flexible diaphragm on the pump chamber responsive to an applied negative pressure, for outward flexure to draw fluid into the well through the pump port, the flexible diaphragm also responsive to an applied positive pressure, for inward flexure to expel fluid from the well through the pump port.

4. A cassette according to claim 3

wherein the pump port communicates with the valve port.

5. A cassette according to claim 1

further including an interior cavity in the body to trap air.

6. A cassette according to claim 5

further including a filter material in the interior cavity.

7. A cassette comprising

a body,

first and second fluid flow channels formed in the body, and

a valve chamber formed in the body comprising a peripheral edge and an interior surface adjoining and recessed below the peripheral edge forming a well, the interior surface extending from the peripheral edge along a plane, a recess formed in the interior surface away from the peripheral edge and extending below the plane of the interior surface, a first valve port in the well communicating with the first fluid flow channel, a second valve port in the well communicating with the second fluid flow channel, one of the first and second valve ports being located in the recess, whereby the recess comprises a recessed valve seat peripherally surrounding the one valve port, and a flexible diaphragm resting on the peripheral edge of the valve chamber responsive to an applied negative pressure for flexure out of the recessed valve seat to open the one valve port and responsive to an applied positive pressure for flexure into the recessed valve seat below the plane of the interior surface to close the one valve port.

8. A cassette according to claim 7

wherein the one valve port includes a terminus that the flexible diaphragm contacts when flexed into the recessed valve seat, and wherein the terminus lays in a plane that is generally coplanar with the plane of the interior surface.

9. A cassette according to claim 7

wherein the other valve port lays in a recess below the plane of the interior wall.

10. A cassette according to claim 7

further including a pump chamber formed in the body comprising a wall forming a well, a pump port in the well communicating with the valve chamber through the one valve port, and

a flexible diaphragm on the pump chamber responsive to an applied negative pressure for outward flexure to draw fluid into the well through the pump port, the flexible diaphragm also responsive to an applied positive pressure for inward flexure to expel fluid from the well through the pump port.

11. A cassette according to claim 7

wherein the body has oppositely sides,

wherein first and second fluid flow channels are formed in one side of the body, and

wherein the valve chamber is formed in the opposite side of the body.

12. A cassette according to claim 7

further including an interior cavity in the body communicating with at least one of the first and second flow channels to trap air.

13. A cassette according to claim 9

further including a filter material in the interior cavity.

14. A cassette for directing fluid flow comprising

a body,

a flow channel formed in the body,

a pump chamber formed in the body and communicating with the flow channel, the pump chamber comprising a wall forming a well, a pump port in the well,

a flexible diaphragm on the pump chamber responsive to an applied negative pressure for outward flexure to draw fluid into the well through the pump port, the flexible diaphragm also responsive to an applied positive pressure for inward flexure to expel fluid from the well through the pump port,

a valve chamber formed in the body comprising a peripheral edge and an interior surface adjoining and recessed below the peripheral edge forming a well, the interior surface extending from the peripheral edge along a plane, a recess formed in the interior surface away from the peripheral edge and extending below the plane of the interior surface, valve port in the recess communicating with the pump port, whereby the recess comprises a recessed valve seat peripherally surrounding the valve seat port,

a flexible diaphragm resting on the peripheral edge of the valve chamber responsive to an applied negative pressure for flexure out of the recessed valve seat to open the valve port and responsive to an applied positive pressure for flexure into the recessed valve seat below the plane of the interior surface to close the valve port,

an interior cavity in the body communicating with the flow channel to trap air, and

a flexible diaphragm on the interior cavity responsive to an applied positive pressure for inward flexure to expel fluid from the interior cavity.

15. A cassette for directing fluid flow comprising

a body,

a pump chamber formed in the body comprising a recessed wall forming a well, a first pump port in the well, and a second pump port in the well spaced from the first port,

a flexible diaphragm on the pump chamber and responsive to an applied negative pressure for outward flexure to draw fluid into the well through one of the ports, the flexible diaphragm also responsive to an applied positive pressure for inward flexure to expel fluid from the well through one of the ports, and

a race extending below the recessed wall between the first and second ports to establish liquid flow continuity between the first and second ports, despite contact between the flexible diaphragm and recessed wall during inward flexure.

16. A cassette according to claim 15

wherein the race includes a dogleg portion job extending at an angle from at least one of the first and second ports.