Flow control system with volume-measuring system using a resonatable mass

• US 5,575,310 A
• Filed: 01/24/1996
• Issued: 11/19/1996
• Est. Priority Date: 03/04/1986
• Status: Expired due to Term

• Current Assignee: Deka Products Limited Partnership
• Original Assignee: Deka Products Limited Partnership
• Inventors: Seale, Joseph B., Kamen, Dean L., Arnold, Finn, Briggs, Joseph
• Primary Examiner(s): NOLAND, THOMAS
• Application Number:
  US08/590,623
• Time in Patent Office: 300 Days
• Field of Search: 73/149, 73/861.18, 137/500, 137/613, 137/503, 137/565, 137/614.11, 137/101.31
• 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 137/85978 : With pump
• CPC Class Codes: Y10T 137/86043 : Reserve or surge receiver
• 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 liquid through a line, the system comprising:

a front chamber disposed in the line, wherein the front chamber has an inlet from the line and an outlet to the line, wherein the front chamber houses a volume of gas in communication with liquid in the chamber, the front chamber having a constant volume so that a change in the volume of liquid in the front chamber results in a corresponding opposite change in the volume of gas in the front chamber;

isolation means for isolating in the front chamber a volume of liquid from pressure effects of liquid in the rest of the line and for dispensing liquid from the front chamber, wherein the isolation means includes a first valve means, located at the inlet, for selectively permitting and preventing flow into the front chamber, and a second valve means, located at the outlet, for selectively permitting and preventing flow out of the front chamber;

a back chamber housing a constant volume of gas;

an orifice containing a resonatable mass of gas and providing fluid communication between the front and back chambers;

signal means for generating an electrical signal;

speaker means for converting the electrical signal into an acoustic response in the front and back chambers;

microphone means for determining the acoustic response; and

control means, in communication with the first and second valve means and the microphone means, for determining the volume of gas in the front chamber and directing the operation of the first and second valve means in order to measure and control flow of liquid through the line.

2. A system according to claim 1, wherein the control means includes:

means for determining a phase change of an acoustic response with respect to the electrical signal causing the acoustic response; and

means for determining the volume of gas in the front chamber based on the phase change.

3. A system according to claim 1, wherein the speaker means is mounted in a wall of the back chamber.

4. A system according to claim 3, wherein the microphone means is mounted in a wall of the back chamber.

5. A system according to claim 4, wherein the control means includes:

means for determining a phase change of an acoustic response with respect to the electrical signal causing the acoustic response; and

means for determining the volume of gas in the front chamber based on the phase change.

6. A system according to claim 1, wherein the liquid and the gas in the front chamber are separated by a solid, flexible membrane.

7. A system according to claim 6, wherein the speaker means is mounted in a wall of the back chamber.

8. A system according to claim 7, wherein the microphone means is mounted in a wall of the back chamber.

9. A system according to claim 8, wherein the control means includes:

means for determining a phase change of an acoustic response with respect to the electrical signal causing the acoustic response; and

means for determining the volume of gas in the front chamber based on the phase change.