Volumetric metering unit for intravenous fluid addition

• US 4,559,044 A
• Filed: 08/03/1982
• Issued: 12/17/1985
• Est. Priority Date: 08/03/1982
• Status: Expired due to Fees

• Current Assignee: General Electric Capital Corporation (General Electric Company)
• Original Assignee: Quest Medical Incorporated (Atrion Corporation)
• Inventors: Robinson, Thomas P., Killman, Don M., Mattson, Andrew P., Hudson, James E. Jr.
• Primary Examiner(s): Truluck, Dalton L.
• Application Number:
  US06/404,811
• Time in Patent Office: 1,232 Days
• Field of Search: 604/65-67, 604/151-153, 604/246, 604/250, 222/450
• US Class Current: 604/246
• CPC Class Codes: A61M 5/16809 by repeated filling and emptying of an intermediate volume pressure infusion using positive displacement pumps A61M5/142
• CPC Class Codes: G01F 11/08 of the diaphragm or bellows type

Abstract

Three embodiments of a metering unit (10, 140, 200) are provided for metering fluid from a container (14) for infusion into a patient. The first embodiment of the metering unit (10) includes a cassette (26) formed of halves (28, 30). The halves (28, 30) each have a concave reservoir portion (36) formed on the inner face (32) thereon. Entry and exit channels (38, 42) extend from the reservoir portions adjacent entry and exit orifices (40, 44). Entry and exit port portions (46, 50) are formed in each half (28, 30). Flexible entry and exit valves (58, 64, 86 and 88) are movable between an open position, permitting fluid to flow through the orifices, to a closed position, preventing fluid from flowing through the orifices. The halves are separated by a flexible diaphragm (70) which divides a reservoir (76) into first and second compartments (78, 80). One entry valve is opened to permit fluid from the entry port (82) to flow into one compartment, the fluid flowing into the compartment moving the flexible diaphragm to force the fluid in the other compartment out to the exit port (84). The position of the valves is then interchanged, permitting fluid to flow into the other compartment and forcing the fluid in the first compartment into the exit port. A cassette (206) in the third embodiment of the unit (200) includes identical halves (208, 210) sonically bonded together. A diaphragm (296) separates parallel channels (218, 222) to reduce head pressure channel volume variations. Grooves (228, 230) are provided in the reservoir portions (216) to prevent fluid trappage between the diaphragm and portion wall. In all cassette embodiments, an activating frame operating the cassette prevents the positioning of all valves in the open position simultaneously.

Claims

1. A cassette for metering a fluid therethrough, comprising:

first and second integrally molded halves secured in facing relation, each of said halves being constructed to form;

a reservoir portion;

at least one inlet channel and at least one outlet channel each extending from the reservoir portion; and

inlet and outlet port sections;

the inlet channel and inlet port section of each being interconnected by an inlet orifice and the outlet channel and the outlet port section of each being interconnected by an outlet orifice, the reservoir portions of each half forming a reservoir and said port sections of each half forming a single entry port and a single exit port;

a flexible diaphragm means positioned between said first and second halves for dividing the reservoir into first and second compartments;

first entry valve means and first exit valve means associated with said first half, said first entry and exit valve means being movable between an open position permitting fluid flow through the inlet and outlet orifices of said first half, respectively, and a closed position to prevent flow through the inlet and outlet orifices, respectively;

second entry valve means and second exit valve means associated with said second half, said second entry and exit valve means being movable between an open position permitting fluid flow through the inlet and outlet orifices of said second half, respectively, and a closed position to prevent fluid flow through the inlet and outlet orifices, respectively;

fluid entering said entry port flowing through the inlet orifice and inlet channel of said first half into the first compartment when said first entry valve means and said second exit valve means are open and said first exit valve means and second entry valve means are closed, to move said diaphragm means to force the fluid in the second compartment through the outlet channel and outlet orifice of said second half to the exit port; and

fluid entering said entry port flowing through the inlet orifice and inlet channel of said second half into the second compartment when said second entry valve means and said first exit valve means are open and said first entry valve means and second exit valve means are closed, to move said diaphragm means to force the fluid in the first compartment through the outlet channel and outlet orifice of said first half to the exit port, the fluid displaced from each of the first and second compartments having a predetermined volume.

3. The apparatus of claim 1 further including activating means for opening and closing each of said valve means.

4. The apparatus of claim 3 wherein said activating means prevents any two valve means associated with the same compartment from being in the open position simultaneously to prevent uncontrolled flow through the apparatus.

5. The apparatus of claim 3 wherein said activating means includes:

a plurality of rod means positioned adjacent the valve means, one rod means for contacting each of said valve means, and means for movement of the rods to open said first entry valve means and said second exit valve means, and means for movement of the rods to open said second entry valve means and said first exit valve means.

7. The apparatus of claim 3 wherein said activating means includes:

frame means for being secured in a fixed relation to said cassette;

clamp means for securing said first and second halves in a fixed relation to said frame means;

a plurality of bar means supported for motion relative to said frame means, each of said bar means contacting one of said valve means to operate the valve means between the closed and opened positions; and

drive means to move said bar means to move said first entry valve means and said second exit valve means to the open position and said second entry valve means and said first exit valve means to the closed position, said drive means subsequently moving said rod means to move said second entry valve means and said first exit valve means to the open position and said first entry valve means and said second exit valve means to the closed position.

10. The apparatus of claim 1 wherein each inlet and outlet channel is divided into a plurality of adjacent sub-channels to reduce variation of the channel cross section at different fluid pressure by varying deflection of the diaphragm means into the channels.

11. The apparatus of claim 1 wherein said reservoir portions include grooves formed within the surfaces thereof to prevent trappage of fluid by the diaphragm means, and said grooves surround a central area which is not traversed by grooves or channels.

2. The apparatus of cliam 1 wherein said first and second halves are identical.

6. The apparatus of claim 6 wherein said activating means permits all of the valve means to be in the closed position simultaneously to prevent fluid flow through the apparatus.

8. The apparatus of claim 8 wherein said drive means includes at least one camming surface operating the bar means to open and close the valve means so that simultaneous positioning of all valve means in the open position is prevented.

9. The apparatus of claim 9 wherein said first and second halves are identical.

12. A cassette for metering a fluid therethrough comprising:

first and second integrally molded halves having confronting surfaces secured in facing relation, each of said first and second halves being constructed to form a reservoir portion, at least one inlet and at least one outlet channel extending along the confronting surface from said reservoir portion and inlet and outlet port sections, the inlet channels and inlet port section being interconnected by an inlet orifice, and the outlet channels and outlet port section being interconnected by an outlet orifice, each of said first and second halves forming a seal surface about each of the orifices, the reservoir portions of said first and second halves forming a reservoir and the inlet port section of each half and the outlet port section of each half combining to form entry and exit ports, respectively;

a flexible diaphragm positioned between said first and second halves so that the reservoir is divided into first and second compartments;

first entry and exit valves mounted on said first half adjacent the entry and exit orifices, said first entry and exit valves having convex resilient sealing surfaces and being movable from an open position permitting fluid flow through said inlet and outlet orifices, respectively, to a closed position in sealing contact with the seal surfaces about the orifices to prevent flow therethrough;

second entry and exit valves mounted on said second half adjacent the entry and exit orifices, said second entry and exit valves having convex resilient sealing surfaces and being movable from an open position permitting fluid flow through said inlet and outlet orifices, respectively, to a closed position in sealing contact with the seal surfaces about the orifices to prevent flow therethrough;

fluid entering said entry port flowing through the inlet orifice and inlet channel of said first half into the first compartment when said first entry valve and second exit valve are open, to move said flexible diaphragm to force fluid in the second compartment through the outlet channel and outlet orifice of said second half to the exit port; and

fluid entering said entry port flowing through the inlet orifice and inlet channel of said second half to the second compartment when said second entry valve and first exit valve are open, to move said flexible diaphragm to force fluid in the first compartment through the outlet channel and outlet orifice of said first half to the exit port, the fluid displaced from each of the first and second compartments having a predetermined volume.

13. The apparatus of claim 13 further comprising:

activating means for alternately opening and closing each of said valves, said first entry valve and said second exit valve being in the same position simultaneously and said second entry valve and said first exit valve being in the opposite position simultaneously, said activating means preventing all said valves from being open simultaneously.

19. The apparatus of claim 13 wherein each of said first and second halves include a plurality of inlet and outlet channels extending into the half for preventing cross-sectional variation in the channels by diaphragm deflection.

20. The apparatus of claim 13 further having grooves formed within the surface of the reservoir portions on each half to prevent trappage of fluid by the diaphragm, and having an ungrooved central surface area.

14. The apparatus of claim 14 wherein said activating means includes:

a frame mounted for pivotal motion relative to said first and second halves when secured in facing relation;

a plurality of rods slidably supported in said frame, one of said rods being positioned adjacent each of said valves;

spring means associated with each of said rods for urging each of said rods into contact with the adjacent valve; and

pivotal motion of said frame in a first direction relative to said first and second halves inducing motion in said rods to open said first entry valve and said second exit valve with said second entry valve and said first exit valve in the closed position, pivotal motion of said frame relative to said first and second halves in the opposite direction inducing motion in said rods to open said second entry valve and said first exit valve with said first entry valve and said second exit valve in the closed position.

16. The apparatus of claim 14 wherein said activating means includes:

a frame secured in a fixed relation to said first and second halves when secured in facing relation;

a plurality of rods slidably mounted on said frame, one of said rods being movable into contact with each of said valves;

spring means associated with each of said rods for urging said rods into contact with each of said valves;

a gear mounted for rotation about an axis fixed relative to said frame;

gear rack means mounted for slidable motion relative to said frame and having teeth for engaging the teeth on said gear, said gear rack means having extension means thereon for contacting each of said rods; and

rotation of said gear in a first direction moving said gear rack means and selected ones of said rods to permit said first entry valve and said second exit valve to be in the open position and said second entry valve and said first exit valve to be in the closed position, rotation of said gear in the opposite direction moving said gear rack means and selected ones of said rods to move said second entry valve and said first exit valve to the open position and said first entry valve and said second exit valve into the closed position.

18. The apparatus of claim 14 wherein said activating means includes:

a frame;

at least one clamp pivoted to said frame;

spring means for urging said clamp to clamp the cassette in a fixed relation to said frame and clamp;

a plurality of arms mounted for motion relative to said frame, each arm for activating one of said valves; and

drive means for operating said arms to alternately open and close said valves, said drive means defining at least one camming surface for contacting selected ones of said arms, the camming surface preventing all valves from being in the open position simultaneously.

15. The apparatus of claim 15 wherein said spring means urges said frame and said plurality of rods into a position wherein all of said valves are in the closed position to prevent fluid flow therethrough.

17. The apparatus of claim 17 wherein said spring means center said gear and said gear rack means so that each of said valves is maintained in the closed position until application of a force to rotate said gear.

21. An apparatus for metering a fluid therethrough, comprising:

a cassette formed from substantially identical first and second integrally-molded halves having inner sides in facing relation and having a flexible diaphragm therebetween, each of said first and second halves being constructed to form a reservoir portion in the inner side thereof, at least two parallel entry channels and at least two parallel exit channels extending from said reservoir portion and entry and exit port sections, said entry channels and entry port section being interconnected through an entry orifice, said exit channels and exit port being interconnected through an exit orifice, the outer side of said first and second halves forming seal surfaces about each of said orifices, the reservoir portion of each of said first and second halves combining to form a reservoir divided into first and second compartments by said flexible diaphragm, each of said entry and exit port sections combining to form entry and exit ports, respectively;

grooves formed in each of said reservoir portion surfaces to prevent trapping of fluid in the reservoir, surrounding a central area of ungrooved reservoir wall;

flexible first entry and exit valves operatively associated with the outer side of said first half, each of said first entry and exit valves having a seal face thereon for sealing engagement with the seal surface about said entry and exit orifices of said first half, respectively, each of said first entry and exit valves being positionable in the open position to permit fluid flow through said entry and exit orifices, respectively, and in the closed position, preventing flow of fluid through said entry orifices, respectively;

flexible second entry and exit valves operatively associated with the outer side of said second half, each of said second entry and exit valves having a seal face thereon for sealing engagement with the seal surface about the entry and exit orifices of said second half, respectively, each of said second entry and exit valves being positionable in the open position permitting fluid flow through the entry and exit orifices of said second half, respectively, and in a closed position, preventing flow of fluid through said entry and exit valves of said second half, respectively; and

said first entry valve and said second exit valve forming a first valve pair and said second entry valve and said first exit valve forming a second valve pair, fluid entering said entry port flowing through the entry orifice and entry channels of said first half into the first compartment when said valves of said first valve pair are open and said valves of said second pair are closed, to force fluid in said second compartment through the exit channels and exit orifice of said second half to said exit port;

fluid entering said entry port flowing through the entry orifice and entry channels of said second half into the second compartment when said valves of said second valve pair are open and said valves of said first pair are closed, to force the fluid in the first compartment through the exit channels and exit orifice of said first half to the exit port, the fluid displaced from each of the first and second compartments having a predetermined volume.

22. The apparatus of claim 22 further comprising activating means for opening and closing each of said valves, said valves of said first valve pair being in the same position and said valves of said second valve pair being in the same position.

23. The apparatus of claim 23 wherein said activating means includes:

a frame mounted for pivotal motion relative to said cassette;

four rods slidably supported in said frame, one of said rods being positioned adjacent each of said valves;

spring means interposed between said frame and each of said rods to urge each of said rods into contact with the adjacent valve, said spring means urging each of the rods to contact the adjacent valve to maintain the valve in a closed position to prevent fluid flow therethrough; and

pivotal motion of said frame in a first direction releasing selected ones of said rods from the adjacent valves to open said first pair of valves while maintaining said second pair of valves in the closed position, said frame being pivotal in the oppposite direction to release selected ones of said rods to move said second pair of valves to the open position while maintaining said first pair of valves in the closed position.

24. The apparatus of claim 23 wherein said activating means includes:

a frame secured in a fixed relation to said cassette;

four rods slidably mounted to said frame, one of said rods being movable into contact with each of said valves;

spring means associated with each of said rods for urging said rods into contact with each of said valves; and

means for contacting selected ones of said rods to open said first pair of valves while maintaining said second pair closed, and for contacting selected ones of said rods to open said second pair of valves while maintaining said first pair closed.

25. The apparatus of claim 23 wherein said activating means includes:

a frame;

first and second clamps pivotally mounted to said frame and having cassette receiving structure thereon;

spring means for urging said clamps together to clamp the cassette in a fixed relationship to said frame and clamps;

inlet and outlet valve activating arms pivotally mounted on each of said clamps for activating selected ones of said inlet and outlet valves, respectively, said valve activating arms having camming surfaces formed thereon; and

a cam shaft assembly mounted for rotation within said frame and defining at least one camming surface thereon for contacting the camming surfaces of said arms, rotation of said cam shaft assembly alternately opening and closing each of said valves through the valve activating arms and preventing all of said valves from being open simultaneously.

26. A cassette for metering a fluid therethrough comprising:

substantially identical first and second halves secured in facing relation, each of said first and second halves being constructed to form a reservoir portion in the surface facing the other half, inlet and outlet fluid paths, each of said paths having at least two parallel channels formed in the facing surface, said fluid paths extending from opposite sides of the reservoir portion to inlet and outlet orifices formed through the half, inlet and outlet seal surfaces being formed concentrically about the opening of the inlet and outlet orifices, respectively, on the side opposite the facing side, inlet and outlet passages formed through a portion of said inlet and outlet seal surface, respectively, opening on the facing side and a stem having a port formed therein in communication with one of said passages;

the reservoir portions of said first and second halves forming a reservoir and said ports forming entry and exit ports;

a flexible diaphragm for positioning between said first and second halves to divide the reservoir into first and second compartments, said diaphragm further acting as a seal between said first and second halves while permitting fluid communication between the entry port and the inlet passages in said first and second halves and the exit port and said outlet passages in said first and second halves;

first entry and exit valves for operative association with said first half, said first entry valve being movable from an open position permitting fluid flow from said inlet passage through the inlet orifice of the first half, and said first exit valve being movable from an open position permitting fluid flow between said outlet orifice and the outlet passage of the first half, to a closed position in sealing contact with the seal surfaces about the respective orifices to prevent flow therethrough;

second entry and exit valves for operative association with said second half, said second entry valve being movable from an open position permitting fluid flow from said inlet passage through said inlet orifice of said second half of said second exit valve being movable from an open position permitting fluid flow between said outlet orifice and the outlet passage of the second half, to a closed position in sealing contact with the seal surfaces about the respective orifices to prevent flow therethrough;

whereupon opening of the first entry valve and the second exit valve, fluid enters said entry port flowing through the inlet passage, inlet orifice and inlet fluid path of said first half into the first compartment to move said flexible diaphragm to force fluid in the second compartment through the outlet fluid path, outlet orifice and outlet passage of said second half to the exit port and;

whereupon opening of the second entry valve and the first exit valve, fluid enters said entry port flowing through the inlet passage, inlet orifice and inlet fluid path in said second half to the second compartment to move the flexible diaphragm to force fluid in the first compartment through the outlet fluid path, outlet orifice and outlet passage of said first half to the exit port, the fluid displaced from each of the first and second compartments having a predetermined volume.

27. The apparatus of claim 27 further comprising:

activating means for operating said valves in at least three conditions, the first condition being with said first entry valve and said second exit valve open and said second entry valve and first exit valve closed, the second condition being with all valves closed and the third condition with said first entry valve and said second exit valve closed and said second entry valve and first exit valve open.

28. The apparatus of claim 27 wherein the channels in each half extend into the surface of the reservoir portion to prevent trappage of fluid by the diaphragm.

29. The apparatus of claim 27 further having grooves formed within the surface of the reservoir portion on each half to prevent trappage of fluid by the diaphragm, and wherein a central planar area of the reservoir portion surface is not traversed by grooves or channels.

30. The apparatus of claim 27 wherein said cassette halves are secured in facing relationship by ultrasonic bonding, the facing surfaces of said halves having cooperating energy directors and ridges surrounding the valve and reservoir area.

31. The apparatus of claim 27 further having finger grips on said first and second halves.

32. The apparatus of claim 27 further comprising at least one pin extending from the facing surface of one of said halves for insertion within at least one hole in the other of said halves to align the halves in facing relationship.

33. The apparatus of claim 28 wherein said activating means comprises:

a frame;

clamps pivotally mounted on said frame for pivotal motion to insert said cassette betwen said clamps;

spring means for urging said clamps together to retain the cassette between said clamps;

a drive shaft rotatably mounted on said frame;

motor means for rotating said drive shaft;

actuating arms pivotally mounted on said clamps for actuating said valves on said cassette;

a plurality of cams mounted on said drive shaft for pivoting said actuating arms, said cams being positioned so that all valves cannot be open simultaneously to permit a controlled fluid flow through the cassette; and

means for sensing the angular position of said drive shaft.

34. The apparatus of claim 34 further comprising means for separating said clamps to permit removal of said cassette.

35. The apparatus of claim 34 wherein said spring means comprise at least one spring secured between said clamps for urging the clamps together to retain the cassette.

36. An apparatus for activating a cassette, the cassette having a central metering chamber divided into first and second compartments by a flexible diaphragm, inlet and outlet ports and at least four fluid flow paths comprising an inlet flow path from the inlet port to each of the two compartments and an outlet flow path from each of the two compartments to the outlet port, each flow path having valve means activatable between open and closed position for blocking fluid flow along the flow path in the closed position, said apparatus comprising:

a frame;

holdng means for securing the cassette in a fixed relationship to said frame;

inlet and outlet valve activating arms operatively connected to said frame for activating said valves, said valve activating arms having camming surfaces formed thereon; and

a cam shaft assembly mounted for rotation within said frame and defining at least one camming surface thereon for contacting the camming surfaces of said arms, rotation of said shaft assembly opening and closing each of said valves through the valve activating arms in a predetermined sequence and preventing all of said valves from being in the open position simultaneously.

37. An apparatus for activating a cassette, the cassette having a metering chamber divided into a first and second compartment by a flexible diaphragm, inlet and outlet ports and four fluid flow paths comprising an inlet flow path from the inlet port to each of the two compartments and an outlet flow path from each of the two compartments to the outlet port, each flow path having valve means activatable between open and closed positions for blocking fluid flow along the flow path in the closed position, said apparatus comprising:

a frame;

first and second clamps pivotally mounted to said frame and having cassette receiving structure thereon;

spring means for urging said clamps together to clamp the cassette in a fixed relationship to said frame and clamps;

valve activating arms pivotally mounted on each of said clamps for activating said valve means, said valve activating arms having camming surfaces formed thereon;

a cam shaft rotatably mounted in said frame; and

control means for rotating said cam shaft between first and second limits, first and second camming surfaces being defined on said cam shaft, the first camming surface for contacting the camming surfaces of the arms activating said inlet flow path valve means and said second camming surface for contacting the camming surfaces of the arms activating said outlet flow path valve means, alternate oscillation of said cam shaft by said control means between the first and second limits activating the valve means in the cassette in at least three conditions, the first condition being the opening of a first pair of inlet and outlet valves means on opposite sides of the diaphragm and closing of the other pair, the second condition being the closing of all valve means and the third condition being the opening of the other pair of inlet and outlet valve means and the closing of said first pair of inlet and outlet valves to control the fluid flow through the cassette.

38. A method for activating a cassette, the cassette having a central metering chamber divided into first and second compartments by a flexible diaphragm, inlet and outlet ports and four fluid flow paths comprising an inlet flow path from the inlet port to each of the two compartments and an outlet flow path from each of the two compartments to the outlet port, each flow path having valves activatable between open and closed positions for blocking fluid flow along the flow path in the closed position, said method comprising the steps of:

securing the cassette to a frame;

mounting valve activating means on said frame for activating said valves;

selecting a desired fluid flow rate through the cassette; and

oscillating a cam shaft between first and second limits, said cam shaft having at least one camming surface thereon for contacting said valve activating means to activate said valves, the inlet valve to the first compartment and outlet valve from the second compartment being open and the inlet valve to the second compartment and outlet valve from the first compartment being closed when said cam shaft is at the first limit to permit a predetermined quantity of fluid to flow from the second compartment and permit fluid to flow into the first compartment;

the inlet valve to the second compartment and outlet valve from the first compartment being open and the inlet valve to the first compartment and outlet valve from the second compartment being closed when said cam shaft is at the second limit to permit a predetermined quantity of fluid to flow from the first compartment and permit fluid to flow into the second compartment, said cam shaft operating said inlet and outlet valve activating means to close all of said valves between the first and second limits, the oscillating of said cam shaft permitting the desired fluid flow rate to pass through the cassette.