Flow conrol system

• US 5,526,844 A
• Filed: 05/18/1995
• Issued: 06/18/1996
• Est. Priority Date: 03/04/1986
• Status: Expired due to Term

• Current Assignee: Deka Products Limited Partnership
• Original Assignee: Deka Products Limited Partnership
• Inventors: Briggs, Joseph, Seale, Joseph B., Kamen, Dean L., Arnold, Finn
• Primary Examiner(s): NOLAND, THOMAS
• Application Number:
  US08/443,429
• Time in Patent Office: 397 Days
• Field of Search: 137/500, 137/503, 137/565, 137/613, 137/614.11, 137/101.31, 73/149, 73/861.18
• US Class Current: 137/614.11
• 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: F04B 43/14 having plate-like flexible members
• 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
• CPC Class Codes: Y10T 137/2541 : With measuring type discharge assistant
• CPC Class Codes: Y10T 137/86027 : Electric
• CPC Class Codes: Y10T 137/87917 : Flow path with serial valves and/or closures
• CPC Class Codes: Y10T 137/87981 : Common actuator

Abstract

A system for controlling the flow of fluid through a line 3. The system may include first and second valves (A, B; and 6, 7) in the line 3 between is located a chamber (52, 82), part of which may be filled with fluid having a variable volume (52), and another part is filled with a measurement gas (V₁), such as air. The chamber may be isolated from the pressure effects in the rest of the line by closing both valves. The valves may also permit fluid to flow into or out of the chamber. The second portion of the chamber has a common boundary with the first part in such a way that the combined volume of the first and second parts is constant. A loudspeaker (22, 33, 571) creates sound waves in the gas in the second part of the chamber, in order to measure the volume of the fluid in the first part, and for directing the operation of the valves and creating subsonic pressure variations to produce the desired flow. The volume measurement is achieved by acoustic volume measurement techniques.

Claims

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

(a) first and second valves in the line;

(b) a first chamber of variable volume disposed in fluid communication between the first and second valves;

(c) a second chamber of variable volume having a common boundary with the first chamber in such a way that the combined volume of the first and second chambers is constant;

(d) pressure means for varying the pressure of a gas in the second chamber subsonically, so as to force fluid between the line and the first chamber;

(e) volume determination means for determining the volume of fluid in the first chamber independently of subsonic pressure variations in the second chamber, the volume determination means including first speaker means for creating an acoustic response in the second chamber, and first microphone means for detecting the acoustic response in the second chamber;

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

2. A system according to claim 1, wherein the volume determination means includes an acoustic volume measurement system of the acoustic-pressure type.

3. A system according to claim 2, wherein the volume determination means further includes

a third chamber, wherein the first speaker means is located in a wall between the second and third chambers, and

second microphone means for detecting the acoustic response in the third chamber.

4. A system according to claim 3, wherein the pressure means includes a volume of gas in fluid communication through a passage with each of the second and third chamber, such that an increase in pressure in the volume increases the pressure in both the second and third chambers, and wherein each passage is dimensioned to minimize effects of resonance and to acoustically isolate the second and third chambers from the volume.

5. A system according to claim 4, wherein the volume determination means further includes

a fourth chamber located adjacent the second chamber, wherein the first microphone means is located in a wall between the second and fourth chambers,

a fifth chamber located adjacent the third chamber, wherein the second microphone means is located in a wall between the third and fifth chambers, and

a second speaker means, located in a wall between the fourth and fifth chambers, for creating an acoustic response in the fourth and fifth chambers.

6. A system according to claim 5, wherein the pressure means'"'"'s volume of gas is in fluid communication through a passage with each of the fourth and fifth chambers, such that an increase in pressure in the volume increases the pressure in both the fourth and fifth chambers, and wherein each passage is dimensioned to minimize effects of resonance and to acoustically isolate the fourth and fifth chambers from the volume and from the other chambers.

7. A system according to claim 1, wherein the volume determination means includes an acoustic resonance system.