Fluid management system with auxiliary dispensing chamber

• US 5,193,990 A
• Filed: 03/22/1991
• Issued: 03/16/1993
• Est. Priority Date: 03/04/1986
• Status: Expired due to Term

• Current Assignee: Deka Products Limited Partnership
• Original Assignee: Deka Products Limited Partnership
• Inventors: Lanigan, Richard J., Kamen, Dean L.
• Primary Examiner(s): Bertsch, Richard A.
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US07/674,818
• Time in Patent Office: 725 Days
• Field of Search: 417/474, 417/479
• US Class Current: 417/474
• CPC Class Codes: A61M 2005/1403 Flushing or purging
• CPC Class Codes: A61M 2205/12 with interchangeable cassettes forming partially or totally the fluid circuit
• CPC Class Codes: A61M 2205/15 Detection of leaks
• CPC Class Codes: A61M 39/22 Valves or arrangement of valves A61M39/02, A61M39/0247, A61M39/16 take precedence; regulating valves in infusion systems A61M5/16881; in devices worn by the patient for the reception of urine, faeces, catamenial or other discharge, or in colostomy devices A61F5/4405
• CPC Class Codes: A61M 39/24 Check- or non-return valves
• CPC Class Codes: A61M 39/26 Valves closing automatically on disconnecting the line and opening on reconnection thereof check valves A61M39/24
• CPC Class Codes: A61M 39/28 Clamping means for squeezing flexible tubes, e.g. roller clamps tube strippers A61M1/83
• 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 5/16809 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 5/16859 Evaluation of pressure response, e.g. to an applied pulse
• CPC Class Codes: A61M 5/36 with means for eliminating or preventing injection or infusion of air into body dialysis systems, blood oxygenators A61M1/14; haemofiltration equipment A61M1/34; automatic tube cut-off A61M39/281
• CPC Class Codes: A61M 5/365 Air detectors A61M5/1684 takes precedence; in extracorporeal blood circuits A61M1/3626
• CPC Class Codes: F04B 43/043 Micropumps
• CPC Class Codes: F16K 31/004 actuated by piezoelectric means
• CPC Class Codes: F16K 31/005 Piezoelectric benders
• CPC Class Codes: G01F 1/34 by measuring pressure or differential pressure
• CPC Class Codes: G01F 1/66 by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters
• CPC Class Codes: G01F 17/00 Methods or apparatus for determining the capacity of containers or cavities, or the volume of solid bodies measuring linear dimensions to determine volume G01B
• CPC Class Codes: G01P 13/0066 by using differences of pressure in the fluid
• CPC Class Codes: G05D 16/0636 : characterised by the loading device of the membrane, e.g. spring
• CPC Class Codes: G05D 16/185 : using membranes within the main valve

Abstract

A system that permits highly accurate flow control, even at very low flow rates, by providing a measurement chamber and an auxiliary dispensing chamber having a volume that is variable between fixed maximum and minimum limits. The maximum volume of the dispensing chamber is substantially smaller than the maximum volume of the measurement chamber used in this type of system. The dispensing chamber can then be filled to its maximum volume from the measurement chamber and thereafter caused to be reduced over time to its minimum volume. Because the maximum and minimum volumes of the dispensing chamber are known, the volume change of the dispensing chamber per unit time is determinable and is the flow rate out of the system.

Claims

1. A system for controlling the flow of fluid through a line, comprising:

(a) first, second, and third valves in series in the line;

(b) a container having first and second regions of variable volume, the first region disposed in fluid communication between the first and second valves;

(d) dispensing chamber means for providing a first dispensing volume, variable between first fixed maximum and minimum limits, disposed in fluid communication between the second and third valves;

(e) volume determination means for determining the volume of fluid in the first region by means of a measurement gas in the second region;

(f) control means, in communication with the volume determination means, the first, second and third valves, the pressure means, and the dispensing chamber means for directing the operation of the valves, the pressure means, and the dispensing means to produce the desired flow through the line.

2. A system according to claim 1, further comprising:

second dispensing chamber means for providing a second dispensing volume, variable between second fixed maximum and minimum limits, disposed in fluid communication between the second and third valves, and in communication with the control means.

3. A system according to claim 1,

wherein the dispensing chamber means includes an associated region of variable volume having a common boundary with the dispensing volume in such a way that the combined volume of the dispensing volume and the associated region is constant, and

further comprising:

dispensing pressure means, for varying the pressure of a gas in the associated region, in communication with the control means.

4. A system according to claim 3, further comprising:

a housing;

a flexible membrane disposed on the housing, the membrane having an internal side facing the housing and an external side facing away from the housing,

the housing and the membrane defining (i) the first region, (ii) the first dispensing volume, and (iii) valving chamber means associated with each of the first, second, and third valves, for providing valving in response to pressure on the external side of the membrane in the vicinity of the valving chamber means.

9. A system according to claim 1, wherein the dispensing chamber is located downstream of the container.

10. A system according to claim 1, wherein the first dispensing volume at its maximum limit is smaller than the container'"'"'s volume at its maximum.

11. A system according to claim 2, wherein the first dispensing volume at its maximum limit is smaller than the container'"'"'s volume at its maximum, and the second dispensing volume at its maximum limit is smaller than the first dispensing vole at its maximum limit.

12. A system according to claim 2, wherein the two dispensing chambers are located downstream of the container.

13. A system according to claim 12, wherein the first dispensing volume at its maximum limit is smaller than the container'"'"'s volume at its maximum, and the second dispensing volume at its maximum limit is smaller than the first dispensing volume at its maximum limit.

5. An assembly for controlling the flow of fluid through a line, comprising:

a housing;

a flexible membrane disposed on the housing, the membrane having an internal side facing the housing and an external side facing away from the housing,

the housing and the membrane defining

(i) first, second and third valving chambers for providing valving in response to pressure on the external side of the membrane in the vicinity of the valving chamber, the valves disposed in series in the line, each of the valves further having first and second mouths for providing fluid communication with the line;

(ii) a first region of variable volume disposed in fluid communication between the first and second valving chambers, and (iii) a dispensing volume, variable between fixed maximum and minimum limits, disposed in fluid communication between the second and third valving chambers.

6. A system according to claim 5, wherein the housing and the membrane further define a second dispensing volume, variable between second fixed maximum and minimum limits, disposed in fluid communication between the second and third valving chambers.

7. A system according to claim 5, wherein the first dispensing volume at its maximum limit is smaller than the first region'"'"'s volume at its maximum.

8. A system according to claim 6, wherein the first dispensing volume at its maximum limit is smaller than the first region'"'"'s volume at its maximum, and the second dispensing volume at its maximum limit is smaller than the first dispensing volume at its maximum limit.