Pump having flexible liner and compounding apparatus having such a pump

• US 6,905,314 B2
• Filed: 10/16/2001
• Issued: 06/14/2005
• Est. Priority Date: 10/16/2001
• Status: Expired due to Fees

• Current Assignee: Baxter International Inc.
• Original Assignee: Baxter International Inc.
• Inventors: Danby, Hal C.
• Primary Examiner(s): FREAY, CHARLES GRANT
• Application Number:
  US09/978,649
• Publication Number:
  US 20030072652A1
• Time in Patent Office: 1,337 Days
• Field of Search: 417/53, 417/384, 417/389, 417392-395, 417/521, 417/478, 417/479, 417/533, 417/413, 222/105, 222/129, 222/130, 222/135, 222/144.5, 222/185.1, 222/214, 222/318, 222/325, 222/459, 604131-133, 604140-146, 604/403, 604/408, 604/251
• US Class Current: 417/53
• CPC Class Codes: F04B 13/02 of two or more fluids at the same time
• CPC Class Codes: F04B 43/025 two or more plate-like pumping members in parallel
• CPC Class Codes: F04B 43/0736 with two or more pumping chambers in parallel

Abstract

A pump has a flexible liner which is expanded and contracted by application of positive and negative fluid pressure for receiving and discharging fluent material. The liner is received in a rigid shell which defines the maximum volume received. In discharging fluent material, a vacuum is applied to one side of the liner, while applying pressure to the other side so the liner is collapsed against the rigid shell. The liner is arranged so as to be the only part of the pump which contacts the fluent material, and is replaceable to effect rapid and easy cleaning of the pump. The liner has multiple pump cells which can expand and contract for moving fluent material through the pump cell. The pump cells can be sized and arranged so that by selection of particular pump cells which receive the fluent material, precise volumes can be metered by the pump.

Claims

1. A pump for pumping a fluent material comprising:

a liner including opposing walls of flexible material defining a plurality of pump cells, an inlet and an outlet, the pump cells being sized and shaped for receiving a quantity of the fluent material and being expandable for receiving fluent material and contractible for discharging fluent material;

a rigid shell adapted to receive and substantially enclose at least the pump cells of the liner, the shell being formed with a plurality of receptacles therein to receive in close fitting relation the pump cells, said receptacles being adapted for connection to a source of pressurized gas and for connection to a vacuum source for selectively applying a vacuum pressure and a positive pressure to the cells to selectively expand and collapse the cells for drawing fluent material into the pump cell and expelling the fluent material from the pump cells;

valves associated with the rigid shell and disposed for pinching engagement with the liner adjacent to the pump cells for selectively blocking and opening fluid communication of the pump cells thereby to pump the fluent material.

2. A pump as set forth in claim 1 wherein at least some of the pump cells are sized for receiving different quantities of fluent material.

3. A pump as set forth in claim 2 wherein at least some of the receptacles are sized differently in correspondence with the differently sized pump cells, each receptacle having a volume selected to define the maximum volume of the corresponding pump cell.

4. A pump as set forth in claim 3 wherein the walls of the liner further define a manifold pump cell disposed between the inlet and at least some of the pump cells, the manifold pump cell being adapted for fluid communication with the inlet and said at least some pump cells, the manifold pump cell being expandible and contractible for receiving fluent material from the inlet and for selectively delivering fluent material to said at least some pump cells.

5. A pump as set forth in claim 4 wherein the walls of the liner further define a header pump cell adapted for fluid communication with said at least some pump cells for receiving fluent material discharged from said pump cells, the header pump cell being expandable and contractible for receiving fluent material from the pump cells and discharging a mixture of said fluent materials.

6. A pump as set forth in claim 5 wherein the walls of the liner further define passages between the inlet and the manifold pump cell, the passages being expandible and contractible for receiving fluent material from the inlet and for selectively delivering fluent material to the manifold pump cell.

7. A pump as set forth in claim 1 wherein the liner walls are joined together to define the pump cells.

8. A pump as set forth in claim 1 wherein the walls of the liner further define a manifold pump cell disposed between the inlet and at least some of the pump cells, the manifold pump cell being adapted for fluid communication with the inlet and said at least some pump cells, the manifold pump cell being expandible and contractible for receiving fluent material from the inlet and for selectively delivering fluent material to said at least some pump cells.

9. A pump as set forth in claim 2 wherein the walls of the liner further define a header pump cell adapted for fluid communication with said at least some pump cells for receiving fluent material discharged from said pump cells, the header pump cell being expandable and contractible for receiving fluent material from the pump cells and discharging a mixture of said fluent material.

10. A pump as set forth in claim 1 in combination with the pressure source and the vacuum source.

11. A pump for pumping a fluent material comprising:

a liner including opposing walls of flexible material defining at least one pump cell, an inlet and an outlet, the pump cell being sized and shaped far receiving a quantity of the fluent material and being expandable for receiving fluent material and contractible for discharging fluent material;

a rigid shell adapted to receive and substantially enclose at least the pump cell of the liner, the shell being formed with at least one receptacle therein to receive in close fitting relation the pump cell, said one receptacle being adapted for connection to a source of pressurized gas and for connection to a vacuum source for selectively applying a vacuum pressure and a positive pressure to the cell to selectively expand and collapse the cell for drawing fluent material into the pump cell and expelling the fluent material from the pump cell;

the rigid shell being adapted to hold the walls of the liner in sealing relation around the receptacle,

valves associated with the rigid shell and disposed for pinching engagement with the liner adjacent to the pump cell for selectively blocking and opening fluid communication of the pump cell thereby to pump the fluent material.

12. A pump as set forth in claim 11 wherein the walls of the liner are free of fixed connection inwardly of a peripheral edge margin of the liner.

13. A pump for pumping a fluent material comprising:

a liner including opposing walls of flexible material defining at least one pump cell, an inlet and an outlet, the pump cell being sized and shaped for receiving a quantity of the fluent material and being expandable for receiving fluent material and contractible for discharging fluent material;

a rigid shell adapted to receive and substantially enclose at least the pump cell of the liner, the shell being formed with at least one receptacle therein to receive in close fitting relation the pump cell, said one receptacle being adapted for connection to a source of pressurized gas and for connection to a vacuum source for selectively applying a vacuum pressure and a positive pressure to the cell to selectively expand and collapse the cell for drawing fluent material into the pump cell and expelling the fluent material from the pump cell;

the shell comprising first and second shell members hingedly attached to each other for opening and closing the shell to receive or remove the liner from the shell,

valves associated with the rigid shell and disposed for pinching engagement with the liner adjacent to the pump cell for selectively blocking and opening fluid communication of the pump cell thereby to pump the fluent material.

14. A pump as set forth in claim 13 wherein the receptacle comprises a first receptacle member defined in the first shell member and a second receptacle member defined in the second shell member.

15. A pump as set forth in claim 13 wherein the liner as received in the shell is disposed between the shell and any fluent material entering the shell whereby, in use, the shell is free of contact with the fluent material.

16. Apparatus for dispensing a customized drink mixture comprising:

a dispensing outlet for dispensing the drink mixture to a container;

a first pump for pumping a base liquid of the drink mixture from a source to the dispensing outlet;

a second pump for metering selected quantities of admixtures to the base liquid for forming with the base liquid the drink mixture in the container, the second pump comprising;

a liner including opposing walls of flexible material selectively joined together to define at least two pump cells sized and shaped for receiving a quantity of one of the admixtures, the liner further including inlets and at least one outlet in communication with the pump cell so that admixture passes through the pump contacting only the liner;

a rigid shell adapted to receive and substantially enclose at least the pump cells of the liner, the shell being formed with receptacles therein to receive in close fitting relation the pump cells, the receptacles being adapted for connection to a source of pressurized gas and for connection to a vacuum source for selectively applying a vacuum pressure and a positive pressure to the cell to selectively expand and collapse the cell for drawing fluent material into the pump cell and expelling the fluent material from the pump cell;

valves associated with the rigid shell and disposed for pinching engagement with the liner adjacent to the pump cells for selectively blocking and opening fluid communication of the pump cells with the inlets and the outlet thereby to pump the admixture.

17. Apparatus as set forth in claim 16 wherein the liner is adapted to be removably received in the shell for disposal and replacement of the liner.

18. Apparatus as set forth in claim 17 wherein the shell has an open a position for receiving and removing the pump cell from the shell and a closed position in which the pump cell is substantially enclosed in the shell.

19. Apparatus as set forth in claim 16 wherein the pump cell as received in the shell is the only part of the pump arranged for contact with the fluent material.

20. Apparatus as set forth in claim 16 wherein the liner walls are joined together to define the pump cells.

21. Apparatus as set forth in claim 16 wherein the walls of the liner are held together in sealing relation around each receptacle by the shell.

22. Apparatus as set forth in claim 16 wherein the shell comprises first and second shell members movable for opening and closing the shell to receive or remove the liner from the shell.

23. Apparatus as set forth in claim 22 wherein each receptacle comprises a first receptacle member defined in the first shell member and a second receptacle member defined in the second shell member.

24. A pump for metering a fluent material comprising:

a pump cell having flexible walls expandable between a fill configuration in which the walls enclose a first volume for receiving fluent material into the pump cell and a discharge configuration in which the walls enclose substantially no volume for discharging fluent material from the pump cell;

a shell defining a space therein adapted to receive the pump cell for substantially enclosing the pump shell;

a pressure source adapted for fluid communication with the shell space for applying positive fluid pressure in the space;

a vacuum source adapted for fluid communication with the shell space for applying vacuum pressure to the shell space;

a control for the pressure source and the vacuum source operable to first apply a vacuum pressure to the shell space for expanding the pump cell to the fill configuration for receiving fluent material into the pump cell, then to apply both a vacuum pressure and a positive fluid pressure for drawing one of the walls of the pump cell against the shell and pressing another of the walls of the pump cell against said one wall for moving the pump cell to the discharge configuration for discharging the fluent material.

25. A pump as set forth in claim 24 wherein the pump cell is adapted to be removably received in the shell for disposal and replacement of the liner.

26. A pump as set forth in claim 25 wherein the shell has an open position for receiving and removing the pump cell from the shell and a closed position in which the pump cell is substantially enclosed in the shell.

27. A pump as set forth in claim 24 wherein the pump cell as received in the shell is the only part of the pump arranged for contact with the fluent material.

28. A pump as set forth in claim 24 further comprising multiple pump cells.

29. A pump as set forth in claim 28 wherein the shell is formed with a receptacle for each pump cell, the receptacle defining the space adapted to receive and substantially enclose a corresponding pump cell.

30. A pump as set forth in claim 28 wherein the shell comprises first and second shell members movable for opening and closing the shell to receive or remove the pump cells from the shell.

31. A pump as set forth in claim 30 wherein each receptacle comprises a first receptacle member defined in the first shell member and a second receptacle member defined in the second shell member.

32. A method of operating a pump including a flexible pump cell expandable to define a volume and contractible to collapse the volume, the method comprising the steps of:

receiving fluent material into the pump cell by creating a vacuum around the pump cell to expand the pump cell;

discharging fluent material from the pump cell by applying a vacuum pressure generally on one side of the pump cell while applying positive pressure to another side of the pump cell for collapsing said other side of the pump cell against said one side to discharge fluent material from the pump cell.

33. A method as set forth in claim 32 further comprising limiting expansion of the pump cell upon said step of creating a vacuum by providing a rigid receptacle receiving at least a portion of the pump cell and engageable with the pump cell upon expansion thereof to define the maximum volume enclosed by the pump cell.

34. A method as set forth in claim 32 further comprising the steps of monitoring the volume of fluent material in the pump cell and selectively closing off the pump cell based upon the monitored amount of fluent material in the pump cell prior to complete evacuation of the pump cell for delivering a partial volume of fluent material from the pump.

35. A method as set forth in claim 32 further comprising isolating a portion of the pump cell prior to said step of discharging fluent material thereby to deliver a partial volume of fluent material from the pump cell.

36. A method as set forth in claim 32 further comprising the steps of monitoring the volume of fluent material in the pump cell, providing an indication when the pump cell is fully expanded but not filled with fluent material, discharging the fluent material from the pump cell in the direction the fluent material entered the pump cell and receiving fluent material again into the pump cell by applying a vacuum pressure around the pump cell.

37. A method as set forth in claim 32 wherein the pump includes multiple expandible and contractible pump cells of different sizes and wherein the method further comprises the step of admitting fluent material only into pump cells selected for delivering a discrete volume upon said discharging step, at least one pump cell being blocked from receiving fluent material upon expansion thereof.

38. A disposable pump liner for use in a rigid shell of a pump, the shell being adapted to receive the liner to meter fluent material without contact of the fluent material with the shell, the pump liner comprising opposed flexible walls constructed for removable reception in the shell, an outlet for discharging fluent material from the liner, a plurality of pump cell defined by the opposed flexible walls, each pump cell being deflectable to a first position defining a first volume for receiving fluent material therein and to a second position defining a second volume less than said first volume by action of a fluid on said cell outside said opposed flexible walls for pumping fluent material from said cell towards the outlet, said plurality of pump cells including at least two pump cells having different volumes for use in pumping different selected volumes of fluent material toward the outlet.

39. A disposable pump liner as set forth in claim 38 wherein the liner is formed with plural pump cells.

40. A disposable pump liner as set forth in claim 39 wherein the liner walls are joined together to define the pump cells.

41. A disposable pump liner as set forth in claim 40 wherein the liner includes locators for locating the liner within the rigid shell.

42. A disposable pump liner as set forth in claim 41 wherein the locators comprises holes arranged in the liner in correspondence with the location of studs on the rigid shell which are received into the holes for location of the liner on the shell.

43. A disposable pump liner as set forth in claim 38 wherein the pump cells include a header pump cell, said two cells being adapted to pump material into the header pump cell.

44. A disposable pump liner as set forth in claim 43 wherein the pump cells include at least two groups of pump cells, each group including at least two pump cells of differing volumes, the pump cells of each group being adapted to pump fluent material into the header pump cell.

45. Compounding apparatus for selectively combining components and dispensing admixtures, the compounding apparatus comprising:

a liner of including opposing walls of flexible material at least partially free of connection to permit motion toward and away from each other, the liner including an inlet for each component to be compounded and at least one outlet;

a shell having multiple receptacles formed therein, the shell being adapted to receive the liner with portions of the liner in registration with corresponding receptacles, the wall portions in registration with the receptacles defining pump cells, the wall portions of each pump cell being expandable to receive a volume of at least one of the components into the pump cell and collapsible to discharge the component from the pump cell;

a pressure control system in fluid communication with the receptacles to selectively affect fluid pressure in the receptacle around the pump cells to cause expansion and contraction of the pump cells for receiving and discharging the components to form the admixture.

46. Compounding apparatus as set forth in claim 45 wherein at least some of the receptacles and pump cells defined therein are of different sizes when expanded for holding different volumes of the components for use in selecting the amount of one of the components in the admixture.

47. Compounding apparatus as set forth in claim 46 wherein the receptacles and pump cells having different sizes are grouped in sets arranged for providing different selected total volumes of discharged component by cooperative action of pump cells in the set.

48. Compounding apparatus as set forth in claim 47 wherein one of the pump cells constituting a manifold pump cell is arranged for selectively discharging into multiple other pump cells of different sizes for metering the volume discharged from the pump.

49. Compounding apparatus as set forth in claim 47 wherein at least some of the pump cells are arranged for discharging components into another of the pump cells constituting a header pump cell whereby components from said pump cells are mixed in the header pump cell prior to discharging from the pump.

50. A pump for metering a fluent material comprising:

a pump cell having flexible walls expandable between a fill configuration in which the walls enclose a first volume for receiving fluent material into the pump cell and a discharge configuration in which the walls enclose a second volume less than the first volume for discharging fluent material from the pump cell;

a shell defining a space therein adapted to receive the pump cell for substantially enclosing the pump cell;

a pressure source adapted for fluid communication with the shell space for applying positive fluid pressure in the space;

a vacuum source adapted for fluid communication with the shell space for applying vacuum pressure to the shell space;

a control for the pressure source and the vacuum source operable to first apply a vacuum pressure to the shell space for expanding the pump cell to the fill configuration for receiving fluent material into the pump cell, then to apply both a vacuum pressure and a positive fluid pressure for drawing one of the walls of the pump cell against the shell and pressing another of the walls of the pump cell toward said one wall for moving the pump cell to the discharge configuration for discharging the fluent material.

51. A pump as set forth in claim 50 wherein the pump cell is adapted to be removably received in the shell for disposal and replacement of the liner.

52. A pump as set forth in claim 50 wherein the pump cell as received in the shell is the only part of the pump arranged for contact with the fluent material.

53. A pump as set forth in claim 50 further comprising multiple pump cells.

54. A pump as set forth in claim 53 wherein the shell is formed with a receptacle for each pump cell, the receptacle defining the space adapted to receive and substantially enclose a corresponding pump cell.

55. A pump as set forth in claim 53 wherein the shell comprises first and second shell members movable for opening and closing the shell to receive or remove the pump cells from the shell.

56. A pump as set forth in claim 55 wherein each receptacle comprises a first receptacle member defined in the first shell member and a second receptacle member defined in the second shell member.

57. A pump for metering a fluent material using a pump cell having flexible walls expandable between a fill configuration in which the walls enclose a first volume for receiving fluent material into the pump cell and a discharge configuration in which the walls enclose a second volume less than the first volume for discharging fluent material from the pump cell, the pump comprising:

a shell defining a space therein adapted to receive the pump cell for substantially enclosing the pump cell;

a pressure source adapted for fluid communication with the shell space for applying positive fluid pressure in the space;

a vacuum source adapted for fluid communication with the shell space for applying vacuum pressure to the shell space;

a control for the pressure source and the vacuum source operable to first apply a vacuum pressure to the shell space for expanding the pump cell to the fill configuration for receiving fluent material into the pump cell, then to apply both a vacuum pressure and a positive fluid pressure for drawing one of the walls of the pump cell against the shell and pressing another of the walls of the pump cell toward said one wall for moving the pump cell to the discharge configuration for discharging the fluent material.

58. A pump as set forth in claim 57 wherein the shell has an open position for receiving and removing the pump cell from the cell and a closed position in which the pump cell is substantially enclosed in the shell.

59. A pump as set forth in claim 58 wherein the shell is formed with multiple receptacles, the receptacle defining the space adapted to receive and substantially enclose a corresponding pump cell of a liner have multiple pump cells.

60. A pump as set forth in claim 58 wherein the shell comprises first and second shell members movable for opening and closing the shell to receive or remove the pump cells from the shell.

61. A pump as set forth in claim 60 wherein each receptacle comprises a first receptacle member defined in the first shell member and a second receptacle member defined in the second shell member.

62. Compounding apparatus for selectively combining components and dispensing admixtures, the compounding apparatus comprising:

a liner of including opposing walls of flexible material at least partially free of connection to permit motion toward and away from each other, the liner including at least one outlet;

a shell having multiple receptacles formed therein, the shell being adapted to receive the liner with portions of the liner in registration with corresponding receptacles, the wall portions in registration with the receptacles defining pump cells, the wall portions of each pump cell being expandable to receive a volume of at least one of the components into the pump cell and collapsible to discharge the component from the pump cell;

a pressure control system in fluid communication with the receptacles to selectively affect fluid pressure in the receptacle around the pump cells to cause expansion and contraction of the pump cells for receiving and discharging the components to form the admixture.

63. A compounding apparatus as set forth in claim 62 wherein the liner is formed such that at least two of the pump cells are capable of fluid communication within the liner with another of the pump cells.

64. Compounding apparatus as set forth in claim 62 wherein at least some of the receptacles and pump cells defined therein are of different sizes when expanded for holding different volumes of the components for use in selecting the amount of one of the components in the admixture.

65. Compounding apparatus as set forth in claim 64 wherein the receptacles and pump cells having different sizes are grouped in sets arranged for providing different selected total volumes of discharged component by cooperative action of pump cells in the set.

66. Compounding apparatus as set forth in claim 65 wherein one of the pump cells constituting a manifold pump cell is arranged for selectively discharging into multiple other pump cells of different sizes for metering the volume discharged from the pump.

67. Compounding apparatus as set forth in claim 65 wherein at least some of the pump cells are arranged for discharging components into another of the pump cells constituting a header pump cell whereby components from said pump cells are mixed in the header pump cell prior to discharging from the pump.

68. Compounding apparatus for selectively combining components and dispensing admixtures using a liner of including opposing walls of flexible material at least partially free of connection to permit motion toward and away from each other, the liner including at least one outlet, the compounding apparatus comprising:

a shell having multiple receptacles formed therein, the shell being adapted to receive the liner with portions of the liner in registration with corresponding receptacles, the wall portions in registration with the receptacles defining pump cells, the wall portions of each pump cell being expandable to receive a volume of at least one of the components into the pump cell and collapsible to discharge the component from the pump cell;

a pressure control system in fluid communication with the receptacles to selectively affect fluid pressure in the receptacle around the pump cells to cause expansion and contraction of the pump cells for receiving and discharging the components to form the admixture.

69. Compounding apparatus as set forth in claim 68 wherein at least some of the receptacles are of different sizes for holding different volumes of the components in the pump cells for use in selecting the amount of one of the components in the admixture.

70. Compounding apparatus as set forth in claim 69 wherein the receptacles having different sizes are grouped in sets arranged for providing different selected total volumes of discharged component by cooperative action of pump cells in receptacles in the set.

71. A pump for pumping a fluent material comprising:

a liner including opposing walls of flexible material defining a plurality of pump cells, the pump cells being sized and shaped for receiving a quantity of the fluent material and being expandable for receiving fluent material and contractible for discharging fluent material;

a rigid shell adapted to receive and substantially enclose at least the pump cells of the liner, the shell being formed with a plurality of receptacles therein to receive in close fitting relation the pump cells, said receptacles being adapted for connection to a source of pressurized gas and for connection to a vacuum source for selectively applying a vacuum pressure and a positive pressure to the cells to selectively expand and collapse the cells for drawing fluent material into the pump cells and expelling the fluent material from the pump cells;

valves associated with the rigid shell and disposed for pinching engagement with the liner adjacent to the pump cells for selectively blocking and opening fluid communication of the pump cells thereby to pump the fluent material.

72. A pump as set forth in claim 71 wherein at least some of the pump cells are sized for receiving different quantities of fluent material.

73. A pump as set forth in claim 72 wherein at least some of the receptacles are sized differently in correspondence with the differently sized pump cells, each receptacle having a volume selected to define the maximum volume of the corresponding pump cell.

74. A pump as set forth in claim 73 wherein the walls of the liner further define a manifold pump cell disposed between the inlet and at least some of the pump cells, the manifold pump cell being adapted for fluid communication with the inlet and said at least some pump cells, the manifold pump cell being expandible and contractible for receiving fluent material from the inlet and for selectively delivering fluent material to said at least some pump cells.

75. A pump as set forth in claim 74 wherein the walls of the liner further define a header pump cell adapted for fluid communication with said at least some pump cells for receiving fluent material discharged from said pump cells, the header pump cell being expandable and contractible for receiving fluent material from the pump cells and discharging a mixture of said fluent materials.

76. A pump as set forth in claim 75 wherein the walls of the liner further define passages between the inlet and the manifold pump cell, the passages being expandible and contractible for receiving fluent material from the inlet and for selectively delivering fluent material to the manifold pump cell.

77. A pump as set forth in claim 71 wherein the liner walls are joined together to define the pump cells.

78. A pump as set forth in claim 71 wherein the walls of the liner further define a manifold pump cell disposed between the inlet and at least some of the pump cells, the manifold pump cell being adapted for fluid communication with the inlet and said at least some pump cells, the manifold pump cell being expandible and contractible for receiving fluent material from the inlet and for selectively delivering fluent material to said at least some pump cells.

79. A pump as set forth in claim 71 wherein the walls of the liner further define a header pump cell adapted for fluid communication with said at least some pump cells for receiving fluent material discharged from said pump cells, the header pump cell being expandable and contractible for receiving fluent material from the pump cells and discharging a mixture of said fluent material.

80. A pump as set forth in claim 71 in combination with the pressure source and the vacuum source.

81. A pump as set forth in claim 80 wherein the shell has an open position for receiving and removing the pump cell from the cell and a closed position in which the pump cell is substantially enclosed in the shell.

82. A pump for pumping a fluent material comprising:

a liner including opposing walls of flexible material defining at least one pump cell, the pump cell being sized and shaped for receiving a quantity of the fluent material and being expandable for receiving fluent material and contractible for discharging fluent material;

a rigid shell adapted to receive and substantially enclose at least the pump cell of the liner, the shell being formed with at least one receptacle therein to receive in close fitting relation the pump cell, said one receptacle being adapted for connection to a source of pressurized gas and for connection to a vacuum source for selectively applying a vacuum pressure and a positive pressure to the cell to selectively expand and collapse the cell for drawing fluent material into the pump cell and expelling the fluent material from the pump cell;

the rigid shell being adapted to hold the walls of the liner in sealing relation around the receptacle;

valves associated with the rigid shell and disposed for pinching engagement with the liner adjacent to the pump cell for selectively blocking and opening fluid communication of the pump cell thereby to pump the fluent material.

83. A pump as set forth in claim 82 wherein the walls of the liner are free of fixed connection inwardly of a peripheral edge margin of the liner.

84. A pump for pumping a fluent material comprising:

a liner including opposing walls of flexible material defining at least one pump cell, the pump cell being sized and shaped for receiving a quantity of the fluent material and being expandable for receiving fluent material and contractible for discharging fluent material;

a rigid shell adapted to receive and substantially enclose at least the pump cell of the liner, the shell being formed with at least one receptacle therein to receive in close fitting relation the pump cell, said one receptacle being adapted for connection to a source of pressurized gas and for connection to a vacuum source for selectively applying a vacuum pressure and a positive pressure to the cell to selectively expand and collapse the cell for drawing fluent material into the pump cell and expelling the fluent material from the pump cell;

the shell comprising first and second shell members hingedly attached to each other for opening and closing the shell to receive or remove the liner from the shell;

valves associated with the rigid shell and disposed for pinching engagement with the liner adjacent to the pump cell for selectively blocking and opening fluid communication of the pump cell thereby to pump the fluent material.

85. A pump as set forth in claim 84 wherein the receptacle comprises a first receptacle member defined in the first shell member and a second receptacle member defined in the second shell member.

86. A pump as set forth in claim 84 wherein the liner as received in the shell is disposed between the shell and any fluent material entering the shell whereby, in use, the shell is free of contact with the fluent material.