Fluid delivery systems and methods

• US 20070228071A1
• Filed: 02/09/2007
• Published: 10/04/2007
• Est. Priority Date: 02/09/2006
• Status: Active Grant

• Current Assignee: Deka Products Limited Partnership
• Original Assignee: Deka Products Limited Partnership
• Inventors: Kamen, Dean, Kerwin, John, Gray, Larry, Beavis, Russell, Kane, Derek
• Granted Patent: US 8,414,522 B2
• Time in Patent Office: Days
• US Class Current: 222/52
• CPC Class Codes: A61B 2560/0412 Low-profile patch shaped housings
• CPC Class Codes: A61B 5/0024 for multiple sensor units attached to the patient, e.g. using a body or personal area network
• CPC Class Codes: A61B 5/1427 Multiple blood sampling, e.g. at periodic or pre-established intervals
• CPC Class Codes: A61B 5/150022 for capillary blood or interstitial fluid
• CPC Class Codes: A61B 5/150175 Adjustment of penetration depth
• CPC Class Codes: A61B 5/150358 Strips for collecting blood, e.g. absorbent optical reagent test strips G01N21/8483; chemical reagent test strips G01N33/4875, G01N33/52
• CPC Class Codes: A61B 5/150389 Hollow piercing elements, e.g. canulas, needles, for piercing the skin
• CPC Class Codes: A61B 5/150503 Single-ended needles hollow piercing element tip design A61B5/150396, needle sets for catheters A61M25/06, needles for bringing media into the body A61M5/32
• CPC Class Codes: A61B 5/15107 Piercing being assisted by a triggering mechanism
• CPC Class Codes: A61B 5/15117 comprising biased elements, resilient elements or a spring, e.g. a helical spring, leaf spring, or elastic strap
• CPC Class Codes: A61B 5/15119 comprising shape memory alloys
• CPC Class Codes: A61B 5/15121 comprising piezos
• CPC Class Codes: A61B 5/15123 comprising magnets or solenoids
• CPC Class Codes: A61B 5/15125 comprising a vacuum or compressed fluids
• CPC Class Codes: A61B 5/15186 Devices loaded with a single lancet, i.e. a single lancet with or without a casing is loaded into a reusable drive device and then discarded after use; drive devices reloadable for multiple use
• CPC Class Codes: A61B 5/6833 Adhesive patches
• CPC Class Codes: A61J 1/20 Arrangements for transferring or mixing fluids, e.g. from vial to syringe
• CPC Class Codes: A61M 2005/1402 Priming
• CPC Class Codes: A61M 2005/14208 with a programmable infusion control system, characterised by the infusion program
• CPC Class Codes: A61M 2005/14252 with needle insertion means
• CPC Class Codes: A61M 2005/14268 : with a reusable and a disposable component
• CPC Class Codes: A61M 2005/14506 : mechanically driven, e.g. spring or clockwork
• CPC Class Codes: A61M 2005/1581 : Right-angle needle-type devices
• CPC Class Codes: A61M 2005/1583 : Needle extractors
• CPC Class Codes: A61M 2005/1585 : Needle inserters
• CPC Class Codes: A61M 2005/1586 : Holding accessories for holding infusion needles on the body holding devices for catheters A61M25/02
• CPC Class Codes: A61M 2005/16863 : Occlusion detection
• CPC Class Codes: A61M 2005/1726 : the body parameters being measured at, or proximate to, the infusion site
• CPC Class Codes: A61M 2205/0266 : Shape memory materials
• CPC Class Codes: A61M 2205/0294 : Piezoelectric materials
• CPC Class Codes: A61M 2205/04 : implanted
• CPC Class Codes: A61M 2205/16 : with back-up system in case of failure
• CPC Class Codes: A61M 2205/18 : with alarm
• CPC Class Codes: A61M 2205/3303 : Using a biosensor
• CPC Class Codes: A61M 2205/3331 : Pressure; Flow
• CPC Class Codes: A61M 2205/3334 : Measuring or controlling the flow rate
• CPC Class Codes: A61M 2205/3337 : Controlling, regulating pressure or flow by means of a valve by-passing a pump
• CPC Class Codes: A61M 2205/3341 : stabilising pressure or flow to avoid excessive variation
• CPC Class Codes: A61M 2205/3368 : Temperature
• CPC Class Codes: A61M 2205/3375 : Acoustical, e.g. ultrasonic, measuring means
• CPC Class Codes: A61M 2205/3379 : Masses, volumes, levels of fluids in reservoirs, flow rates
• CPC Class Codes: A61M 2205/3389 : Continuous level detection A61M2205/3393 takes precedence
• CPC Class Codes: A61M 2205/3523 : using telemetric means
• CPC Class Codes: A61M 2205/3546 : Range
• CPC Class Codes: A61M 2205/3569 : sublocal, e.g. between console and disposable
• CPC Class Codes: A61M 2205/3576 : with non implanted data transmission devices, e.g. using external transmitter or receiver
• CPC Class Codes: A61M 2205/3592 : using telemetric means, e.g. radio or optical transmission
• CPC Class Codes: A61M 2205/50 : with microprocessors or computers
• CPC Class Codes: A61M 2205/502 : User interfaces, e.g. screens or keyboards
• CPC Class Codes: A61M 2205/52 : with memories providing a history of measured variating parameters of apparatus or patient
• CPC Class Codes: A61M 2205/581 : by audible feedback
• CPC Class Codes: A61M 2205/582 : by tactile feedback
• CPC Class Codes: A61M 2205/583 : by visual feedback
• CPC Class Codes: A61M 2205/8206 : battery-operated
• CPC Class Codes: A61M 2205/8237 : Charging means
• CPC Class Codes: A61M 2206/22 : eliminating pulsatile flows, e.g. by the provision of a dampening chamber
• CPC Class Codes: A61M 2207/00 : Methods of manufacture, assembly or production
• CPC Class Codes: A61M 2209/045 : for filling, e.g. for filling reservoirs
• CPC Class Codes: A61M 2230/201 : Glucose concentration
• CPC Class Codes: A61M 5/141 : with capillaries for restricting fluid flow
• CPC Class Codes: A61M 5/1413 : Modular systems comprising interconnecting elements
• CPC Class Codes: A61M 5/142 : Pressure infusion, e.g. using pumps
• CPC Class Codes: A61M 5/14212 : Pumping with an aspiration and an expulsion action
• CPC Class Codes: A61M 5/14216 : Reciprocating piston type
• CPC Class Codes: A61M 5/14224 : Diaphragm type
• CPC Class Codes: A61M 5/14232 : Roller pumps
• CPC Class Codes: A61M 5/14244 : adapted to be carried by the patient, e.g. portable on the body
• CPC Class Codes: A61M 5/14248 : of the skin patch type
• CPC Class Codes: A61M 5/1452 : pressurised by means of pistons
• CPC Class Codes: A61M 5/14586 : pressurised by means of a flexible diaphragm
• CPC Class Codes: A61M 5/148 : flexible, e.g. independent bagsA61M5/155 takes precedence
• CPC Class Codes: A61M 5/152 : pressurised by contraction of elastic reservoirs containers for dispensing contents by contraction of an elastic bag provided therein, in general B65D83/0061
• CPC Class Codes: A61M 5/158 : Needles for infusions; Accessories therefor, e.g. for inserting infusion needles, or for holding them on the body
• CPC Class Codes: A61M 5/162 : Needle sets, i.e. connections by puncture between reservoir and tube ; Connections between reservoir and tube in jet-action syringes A61M5/30; connectors for tubes having sealed ends and a needle for piercing them A61M39/14
• CPC Class Codes: A61M 5/168 : Means for controlling media flow to the body or for metering media to the body, e.g. drip meters, counters ; Monitoring media flow to the body flow control in general G05D7/00
• CPC Class Codes: A61M 5/16804 : Flow controllers
• 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: A61M 5/16813 : by controlling the degree of opening of the flow line
• CPC Class Codes: A61M 5/16831 : Monitoring, detecting, signalling or eliminating infusion flow anomalies low-level float-valves causing cut-off A61M5/40; indicating or recording presence, absence or direction of flow in general G01P13/0066
• CPC Class Codes: A61M 5/16886 : for measuring fluid flow rate, i.e. flowmeters
• CPC Class Codes: A61M 5/172 : electrical or electronic A61M5/16804, A61M5/16831 take precedence
• CPC Class Codes: A61M 5/1723 : using feedback of body parameters, e.g. blood-sugar, pressure measurement of body parameters A61B5/00
• CPC Class Codes: A61M 5/3287 : Accessories for bringing the needle into the body; Automatic needle insertion A61M5/20, A61M5/31525 take precedence
• CPC Class Codes: A61M 5/365 : Air detectors A61M5/1684 takes precedence; in extracorporeal blood circuits A61M1/3626
• CPC Class Codes: A61M 5/5086 : for indicating if defective, used, tampered with or unsterile
• CPC Class Codes: B23P 15/00 : Making specific metal objects by operations not covered by a single other subclass or a group in this subclass
• CPC Class Codes: F04B 43/02 : having plate-like flexible members, e.g. diaphragms F04B43/14 takes precedence
• CPC Class Codes: F04B 43/09 : Pumps having electric drive
• CPC Class Codes: F04B 43/1253 : by using two or more rollers as squeezing elements, the rollers moving on an arc of a circle during squeezing
• CPC Class Codes: F04B 7/00 : Piston machines or pumps characterised by having positively-driven valving
• CPC Class Codes: F04C 2230/60 : Assembly methods
• CPC Class Codes: G01F 22/00 : Methods or apparatus for measuring volume of fluids or fluent solid material, not otherwise provided for
• CPC Class Codes: G05B 23/02 : Electric testing or monitoring
• CPC Class Codes: G05D 7/0647 : the plurality of throttling means being arranged in series
• CPC Class Codes: G05D 7/0676 : by action on flow sources G05D7/0688, G05D7/0694 take precedence
• CPC Class Codes: G08C 17/02 : using a radio link
• CPC Class Codes: H04B 7/2609 : Arrangements for range control, e.g. by using remote antennas
• CPC Class Codes: Y10T 29/49236 : Fluid pump or compressor making
• CPC Class Codes: Y10T 29/494 : Fluidic or fluid actuated device making
• CPC Class Codes: Y10T 29/49412 : with assembly, disassembly or composite article making
• CPC Class Codes: Y10T 29/49826 : Assembling or joining
• CPC Class Codes: Y10T 29/49828 : Progressively advancing of work assembly station or assembled portion of work

Abstract

A method of dispensing fluid includes three processes. A first one of these processes includes pumping fluid into a resilient variable-volume dispensing chamber. The dispensing chamber is in series with a normally present finite fluid impedance and an output. The impedance is sufficient so as to cause expansion of the dispensing chamber as it receives pumped fluid even while some fluid flows through the output. Another one of these processes includes repeatedly measuring a parameter related to volume of the dispensing chamber over time. A third one of these processes includes controlling the pumping of fluid based on repeated measurements of the parameter to produce a desired fluid flow through the output. A corresponding system for dispensing fluid implements these processes.

Claims

1. A method of dispensing fluid comprising:

(a) pumping fluid into a resilient variable-volume dispensing chamber, the dispensing chamber in series with a normally present finite fluid impedance and an output, the impedance being sufficient so as to cause expansion of the dispensing chamber as it receives pumped fluid even while some fluid flows through the output;

(b) repeatedly measuring a parameter related to volume of the dispensing chamber over time; and

(c) controlling the pumping of fluid based on repeated measurements of the parameter to produce a desired fluid flow through the output.

2. A method according to claim 1, wherein repeatedly measuring the parameter includes:

acoustically exciting gas in an acoustically contiguous region to produce an acoustic response therein, the region including a subregion coupled to the dispensing chamber so that a change in volume of the dispensing chamber causes a change in volume of the subregion, and

characterizing the acoustic response.

3. A method according to claim 2, wherein acoustically exciting the gas is at only a single frequency and characterizing the acoustic response includes determining a phase relationship between the acoustic response, as measured at a first position in the acoustically contiguous region, and a reference for the single frequency, and the method further includes calculating a change of volume of the subregion based on temporal evolution of the phase relationship.

4. A method according to claim 1, wherein the impedance is a passive impedance.

5. A method according to claim 4, wherein the passive impedance includes a conduit.

6. A method according to claim 5, wherein the conduit comprises coiled tubing.

7. A method according to claim 6, wherein the coiled tubing includes at least two turns.

8. A method according to claim 5, wherein the conduit has a serpentine shape.

9. A method according to claim 5, wherein the conduit has a length and an internal diameter selected to provide a predetermined impedance based on at least one of a viscosity and a density of the fluid.

10. A method according to claim 9, wherein the internal diameter is sufficiently large as to prevent occlusion due to flow of a therapeutic liquid through the conduit.

11. A method according to claim 10, wherein the conduit has a length greater than 2 cm.

12. A method according to claim 5, wherein processes (a), (b), and (c) are performed by components inside a patch-sized housing, the housing having a largest dimension, and the conduit has a length greater than the largest dimension.

13. A method according to claim 5, wherein the conduit includes a length selected to provide a predetermined impedance based on at least one of a viscosity and a density of the fluid.

14. A method according to claim 5, wherein the dispensing chamber has an inlet, and the conduit has an internal diameter less than an internal diameter of the dispensing chamber inlet.

15. A method according to claim 1 wherein pumping fluid comprises:

providing an inlet line connectable to an upstream fluid source, the inlet line in downstream fluid communication with a pumping chamber, the pumping chamber having a pump outlet; and

actuating a force application assembly so as to restrict retrograde flow of fluid through the inlet while pressurizing the pumping chamber to urge flow through the pump outlet.

16. A method according to claim 15, wherein actuating the force application assembly includes using travel of the force application assembly during a work stroke to restrict retrograde flow and to pressurize the pumping chamber in a single mechanical action.

17. A method according to claim 16, wherein a given degree of travel of the force actuation assembly restricts retrograde flow, and a greater degree of travel pressurizes the pumping chamber.

18. A method according to claim 15, wherein actuating the force application assembly includes restricting retrograde flow toward the fluid source by occluding the inlet line.

19. A method according to claim 15, further comprising:

preventing reverse flow of fluid from a dispensing chamber into the pumping chamber by using a passive valve placed therebetween.

20. A method according to claim 1, wherein pumping fluid further comprises allowing a portion of the fluid to return to a fluid source rather than enter the dispensing chamber.

21. A device for dispensing fluid, the device comprising:

a patch-sized housing;

a pump enclosed in the housing;

a dispensing assembly, downstream of the pump and in fluid communication with it, the dispensing assembly having a resilient dispensing chamber and a sensor for measuring quantitatively a parameter related to a volume of the dispensing chamber or the volume'"'"'s derivative with respect to time;

wherein the pump ejects fluid in a pulsatile manner so as to cyclically expand the resilient dispensing chamber, the chamber repeatedly delivering fluid through an exit; and

a control loop coupled to the sensor and the pump for controlling actuation of the pump during normal flow conditions based on the measured parameter so as to achieve delivery of fluid having a desired cumulative volume, the loop including a controller that determines the cumulative volume of fluid delivered through the exit based on the measured parameter.

22. A device according to claim 21, further comprising:

an acoustic energy source for acoustically exciting gas in an acoustically contiguous region, to produce an acoustic response therein, the region including a subregion coupled to the dispensing chamber so that a change in volume of the dispensing chamber causes a change in volume of the subregion; and

a processor;

and wherein the sensor includes a first acoustic transducer, mounted at a first position in the acoustically contiguous region, for producing an electrical signal based on the acoustic response;

the processor, coupled to the first acoustic transducer and to a reference, and implementing a flow determination process for determining a quantity related to change of volume of the subregion based on the acoustic response.

23. A device according to claim 22, wherein the acoustic energy source excites the gas at only a single frequency and the electrical signal produced by the first acoustic transducer has a phase relationship with respect to the reference;

and the flow determination process determines a quantity related to change of volume of the subregion based on temporal evolution of the phase relationship.

24. A device according to claim 21, further comprising:

a finite fluid impedance coupled to the exit, the impedance being sufficient to permit such expansion of the resilient dispensing chamber.

25. A device according to claim 24, wherein the impedance is a passive impedance.

26. A device according to claim 25, wherein the passive impedance includes a conduit.

27. A device according to claim 26, wherein the conduit comprises coiled tubing.

28. A device according to claim 27, wherein the coiled tubing includes at least two turns.

29. A device according to claim 26, wherein the conduit has a serpentine shape.

30. A device according to claim 26, wherein the conduit has a length and an internal diameter selected to provide a predetermined impedance based on at least one of a viscosity and a density of the fluid.

31. A device according to claim 30, wherein the internal diameter is sufficiently large as to prevent occlusion due to flow of a therapeutic liquid through the conduit.

32. A device according to claim 31, wherein the conduit has a length greater than 2 cm.

33. A device according to claim 26, wherein the housing has a largest dimension, and the conduit has a length greater than the largest dimension.

34. A device according to claim 26, wherein the dispensing chamber has an inlet, and the conduit has an internal diameter less than an internal diameter of the dispensing chamber inlet.

35. A device according to claim 21, wherein the pump includes:

a pumping chamber having an inlet connectable to provide fluid communication with a fluid source, and a pump outlet; and

a force application assembly adapted to provide a compressive stroke to the pumping chamber,

wherein the compressive stroke causes a restriction of retrograde flow of fluid from the pumping chamber through the inlet while urging fluid from the pumping chamber to the pump outlet.

36. A device according to claim 35, wherein the force application assembly is coupled to an inlet valve actuator and to a pump actuator, so that the compressive stroke actuates an inlet valve coupled between the inlet and the fluid source to close the valve when the pump actuator causes fluid to be urged from the pumping chamber to the pump outlet.

37. A device according to claim 36, wherein the force application assembly includes a plate coupled to the valve actuator, to the pump actuator, and to a motor for coordinated operation of the valve actuator and the pump actuator.

38. A device according to claim 37, wherein the motor includes a shape-memory actuator.

39. A device according to claim 38, wherein the motor includes at least one pulley for folding the shape-memory actuator to fit within the reusable portion.

40. A device according to claim 21, further comprising a shunt line in fluid communication with an output of the pump and a fluid source, the shunt line allowing a portion of the fluid ejected by the pump to return to the fluid source.

41. A device according to claim 40, wherein the fluid source includes a non-pressurized fluid reservoir.

42. A device for dispensing fluid, the device comprising:

a patch-sized housing, the housing enclosing a source of pressurized fluid in series with a downstream flow-impeding tortuous conduit.

43. A device according to claim 42, further comprising:

a sensor for measuring a parameter related to flow of fluid to the conduit; and

a control loop for adjusting the flow of fluid based on the measured parameter.

44. A device according to claim 42, wherein the source includes a pump operably coupled to provide pressurized fluid to the downstream flow-impeding tortuous conduit.

45. A device according to claim 44, wherein the pump includes:

a pumping chamber having an inlet connectable to provide fluid communication with a fluid source, and a pump outlet; and

a force application assembly adapted to provide a compressive stroke to the pumping chamber,

wherein the compressive stroke causes a restriction of retrograde flow of fluid from the pumping chamber through the inlet while urging fluid from the pumping chamber to the pump outlet.

46. A device according to claim 45, wherein the force application assembly is coupled to an inlet valve actuator and to a pump actuator, so that the compressive stroke actuates an inlet valve coupled between the inlet and the fluid source to close the valve when the pump actuator causes fluid to be urged from the pumping chamber to the pump outlet.

47. A device according to claim 46, wherein the force application assembly includes a plate coupled to the valve actuator, to the pump actuator, and to a motor for coordinated operation of the valve actuator and the pump actuator.

48. A device according to claim 47, wherein the motor includes a shape-memory actuator.

49. A device according to claim 48, wherein the motor includes at least one pulley for folding the shape-memory actuator to fit within the reusable portion.

50. A device according to claim 44, further comprising a shunt line in fluid communication with an output of the pump and a fluid source, the shunt line allowing a portion of the fluid ejected by the pump to return to the fluid source.

51. A device according to claim 50, wherein the fluid source includes a non-pressurized fluid reservoir.

52. A device according to claim 44, further comprising:

a sensor for measuring a parameter related to flow of fluid to the conduit; and

a control loop for adjusting operation of the pump based on the measured parameter.

53. A device according to claim 44, wherein the source further includes a non-pressurized reservoir operably coupled to provide fluid to the pump.

54. A device according to claim 42, wherein the flow-impeding tortuous conduit comprises coiled tubing.

55. A device according to claim 54, wherein the coiled tubing includes at least two turns.

56. A device according to claim 42, wherein the flow-impeding tortuous conduit has a serpentine shape.

57. A device according to claim 42, wherein the housing includes a disposable portion having an integral fluid path including the flow-impeding tortuous conduit.

58. A device according to claim 42, wherein the conduit is disposed within the housing.

59. A device according to claim 42, wherein the conduit has a length and an internal diameter selected to provide a predetermined impedance based on at least one of a viscosity and a density of the fluid.

60. A device according to claim 42, wherein the internal diameter is sufficiently large as to prevent occlusion due to flow of a therapeutic liquid through the conduit.

61. A device according to claim 42, wherein the conduit has a length greater than 2 cm.

62. A device according to claim 42, wherein the housing has a largest dimension, and the conduit has a length greater than the largest dimension.

63. A device according to claim 42, further comprising:

a dispensing chamber in fluid communication with the source and the conduit, the dispensing chamber including an inlet through which fluid is received from the source and an outlet through which fluid is provided to the conduit.

64. A device according to claim 63, wherein the conduit has an internal diameter less than an internal diameter of the dispensing chamber inlet.

65. A device according to claim 63, wherein the dispensing chamber is a resilient variable-volume dispensing chamber.

66. A device according to claim 63, wherein the conduit has an effective diameter less than an effective diameter of the inlet.

67. A device for dispensing fluid, the device comprising:

a patch-sized housing,

a pump disposed within the housing, the pump having a pump outlet;

a dispensing chamber also disposed in the housing, the dispensing chamber having a dispensing inlet and a dispensing outlet, wherein the dispensing inlet is coupled to the pump outlet; and

a tortuous conduit coupled to the dispensing outlet to provide flow-impedance.

68. A device according to claim 67, further comprising:

a sensor for measuring a parameter related to flow of fluid to the conduit; and

a control loop for adjusting operation of the pump based on the measured parameter.

69. A device according to claim 67, further comprising:

a non-pressurized reservoir disposed within the housing and operably coupled to provide fluid to an inlet of the pump.

70. A device according to claim 67, wherein the tortuous conduit comprises coiled tubing.

71. A device according to claim 70, wherein the coiled tubing includes at least two turns.

72. A device according to claim 67, wherein the tortuous conduit has a serpentine shape.

73. A device according to claim 67, wherein the housing includes a disposable portion having an integral fluid path including the tortuous conduit.

74. A device according to claim 67, wherein the conduit is disposed within the housing.

75. A device according to claim 67, wherein the conduit has a length greater than 2 cm.

76. A device according to claim 67, wherein the housing has a largest dimension, and the conduit has a length greater than the largest dimension.

77. A device according to claim 67, wherein the conduit includes an effective diameter selected to provide a predetermined impedance based on at least one of a viscosity and a density of the fluid.

78. A device according to claim 67, wherein the conduit has a length and an internal diameter selected to provide a predetermined impedance based on at least one of a viscosity and a density of the fluid.

79. A device according to claim 67, wherein the dispensing chamber is a resilient variable-volume dispensing chamber.

80. A device according to claim 67, wherein the dispensing chamber has an inlet, and the conduit has an internal diameter less than an internal diameter of the dispensing chamber inlet.

81. A device according to claim 67, wherein the pump includes:

a pumping chamber having an inlet connectable to provide fluid communication with a fluid source, and a pump outlet; and

a force application assembly adapted to provide a compressive stroke to the pumping chamber,

wherein the compressive stroke causes a restriction of retrograde flow of fluid from the pumping chamber through the inlet while urging fluid from the pumping chamber to the pump outlet.

82. A device according to claim 81, wherein the force application assembly is coupled to an inlet valve actuator and to a pump actuator, so that the compressive stroke actuates an inlet valve coupled between the inlet and the fluid source to close the valve when the pump actuator causes fluid to be urged from the pumping chamber to the pump outlet.

83. A device according to claim 82, wherein the force application assembly includes a plate coupled to the valve actuator, to the pump actuator, and to a motor for coordinated operation of the valve actuator and the pump actuator.

84. A device according to claim 83, wherein the motor includes a shape-memory actuator.

85. A device according to claim 84, wherein the motor includes at least one pulley for folding the shape-memory actuator to fit within the reusable portion.

86. A device according to claim 67, further comprising a shunt line in fluid communication with the pump outlet and a fluid source, the shunt line allowing a portion of the fluid ejected by the pump to return to the fluid source.

87. A device according to claim 86, wherein the fluid source includes a non-pressurized fluid reservoir.

88. A method for measuring flow of fluid delivered through a line, the method comprising:

acoustically exciting gas in an acoustically contiguous region at only a single frequency, to produce an acoustic response, during a course of change of a volume of a subregion of the acoustically contiguous region caused by flow of the fluid in a zone coupled to the volume of the subregion;

determining a phase relationship between the acoustic response, as measured at a first position in the acoustically contiguous region, and a reference for the single frequency;

calculating a change of volume of the subregion based on temporal evolution of the phase relationship; and

inferring a measure of fluid flow through the line based on the change of volume of gas in the subregion.

89. A method according to claim 88, further comprising measuring the reference at a second position in the acoustically contiguous region.

90. A method according to claim 88, wherein the zone is coupled to the volume of the subregion via a membrane.

91. A method according to claim 88, wherein the step of acoustically exciting gas includes driving a transducer.

92. A method according to claim 88, wherein the step of acoustically exciting gas includes driving a speaker.

93. A method according to claim 88, further including calibrating the phase relationship as a function of the volume of the subregion.

94. A method according to claim 88, wherein the acoustically contiguous region has a volume less than 200 microliters.

95. A method according to claim 88, wherein the acoustically contiguous region has a volume less than 130 microliters.

96. A method according to claim 88, wherein the acoustically contiguous region has a volume less than 10 microliters.

97. A method according to claim 88, wherein calculating the change in volume includes determining such change with a resolution of better than 20 nanoliters.

98. A method according to claim 88, wherein calculating the change in volume includes determining such change with a resolution of better than 15 nanoliters.

99. A method according to claim 88, wherein calculating the change in volume includes determining such change with a resolution of better than 13 nanoliters.

100. A method according to claim 88, wherein calculating the change in volume includes determining such change with a resolution of at least one ten-thousandth of the volume of the acoustically contiguous region.

101. A method according to claim 88, wherein the single frequency is at or close to a frequency of resonance of the subregion.

102. A method according to claim 88, further comprising:

running a calibration phase by acoustically exciting the region at a succession of frequencies and determining a transfer function characterizing phase relationship between the acoustic response, as measured at a first position in the acoustically contiguous region, and a reference for each of the succession of frequencies, as a function of the frequencies.

103. A method according to claim 102, further comprising measuring the reference for each of the succession of frequencies at a second position in the acoustically contiguous region.

104. A method according to claim 102, further comprising detecting presence of a bubble based on the transfer function.

105. A method according to claim 104, further comprising entering an alarm condition on detecting presence of the bubble.

106. A method according to 102, wherein calculating the change in volume is performed repeatedly during a measurement phase and the measurement phase is performed in alternation with the calibration phase.

107. A method according to claim 106, wherein the fluid is delivered in cycles, and the calibration and measurement phases are coordinated with the cycles.

108. A system for measuring flow of fluid delivered through a line, the system comprising:

an acoustic energy source for acoustically exciting gas in an acoustically contiguous region at only a single frequency, to produce an acoustic response, during a course of change of a volume of a subregion of the acoustically contiguous region caused by flow of the fluid in a zone coupled to the volume of the subregion;

a first acoustic transducer, mounted at a first position in the acoustically contiguous region, for producing an electrical signal based on the acoustic response, the electrical signal of the first acoustic transducer having a phase relationship with respect to a reference; and

a processor, coupled to the first acoustic transducer and to the reference, implementing a flow determination process for determining a quantity related to change of volume of the subregion based on temporal evolution of the phase relationship; and

for inferring a measure of fluid flow through the line based on the change of volume of gas in the subregion.

109. A system according to claim 108, further comprising a second acoustic transducer, mounted in a second position in the acoustically contiguous region, for producing an electrical signal constituting the reference.

110. A system according to claim 108, wherein the system has a power consumption of less than 500 joules per day.

111. A fluid delivery system utilizing a system for measuring flow of fluid delivered through a line in accordance with claim 108, the fluid delivery system causing flow of fluid delivered through the line, and further comprising:

a pump, coupled to the processor;

wherein power consumption by the processor is not substantially greater than power consumption by the pump.

112. A system according to claim 111, wherein the pump includes:

a pumping chamber having an inlet connectable to provide fluid communication with a fluid source, and a pump outlet; and

a force application assembly adapted to provide a compressive stroke to the pumping chamber,

wherein the compressive stroke causes a restriction of retrograde flow of fluid from the pumping chamber through the inlet while urging fluid from the pumping chamber to the pump outlet.

113. A system according to claim 112, wherein the force application assembly is coupled to an inlet valve actuator and to a pump actuator, so that the compressive stroke actuates an inlet valve coupled between the inlet and the fluid source to close the valve when the pump actuator causes fluid to be urged from the pumping chamber to the pump outlet.

114. A system according to claim 113, wherein the force application assembly includes a plate coupled to the valve actuator, to the pump actuator, and to a motor for coordinated operation of the valve actuator and the pump actuator.

115. A system according to claim 114, wherein the motor includes a shape-memory actuator.

116. A system according to claim 115, wherein the motor includes at least one pulley for folding the shape-memory actuator to fit within the reusable portion.

117. A system according to claim 108, further comprising a membrane that couples the zone to the volume of the subregion.

118. A system according to claim 108, wherein the acoustic energy source includes an acoustic transducer coupled to an electrical signal.

119. A system according to claim 108, wherein the transducer is a speaker.

120. A system according to claim 108, wherein the processor implements a calibration process for calibrating the phase relationship as a function of the volume of the subregion.

121. A system according to claim 108, wherein the acoustically contiguous region has a volume less than 200 microliters.

122. A system according to claim 108, wherein the acoustically contiguous region has a volume less than or equal to 130 microliters.

123. A system according to claim 108, wherein the acoustically contiguous region has a volume less than 10 microliters.

124. A system according to claim 108, wherein the flow determination process determines a quantity related to a change of volume corresponding to a resolution of better than 20 nanoliters.

125. A system according to claim 108, wherein the flow determination process determines a quantity related to a change of volume corresponding to a resolution of better than 15 nanoliters.

126. A system according to claim 108, wherein the flow determination process determines a quantity related to a change of volume corresponding to a resolution of better than 13 nanoliters.

127. A system according to claim 108, wherein the flow determination process determines a quantity related to a change of volume corresponding to a resolution of at least one ten-thousandth of the volume of the acoustically contiguous region.

128. A system according to claim 108, wherein the single frequency is at or close to a frequency of resonance of the subregion.

129. A system according to claim 108, wherein:

the acoustic source includes a sound-emitting transducer coupled to the processor;

the processor implements a calibration process in which it causes the acoustic source to acoustically excite the region at a succession of frequencies; and

, as part of such process, the processor determines a transfer function characterizing phase relationship, between the electrical signal of the first transducer and a reference for each of the succession of frequencies, as a function of the frequencies.

130. A system according to claim 129, wherein the processor implements a bubble detection process for detecting presence of a bubble based on the transfer function.

131. A system according to claim 130, wherein the bubble detection process causes the system to enter an alarm condition on detecting presence of the bubble.

132. A system according to claim 131, wherein the flow determination process is performed repeatedly during a measurement phase and the measurement phase is performed in alternation with the calibration process.

133. A system according to claim 132, wherein the fluid is delivered in cycles, and the calibration processes and measurement phases are coordinated with the cycles.