Flow control system using boyle's law

• US 4,778,451 A
• Filed: 03/04/1986
• Issued: 10/18/1988
• Est. Priority Date: 03/04/1986
• Status: Expired due to Term

• Current Assignee: Deka Products Limited Partnership
• Original Assignee: Dean Kamen
• Inventors: Kamen, Dean L.
• Primary Examiner(s): Pellegrino, Stephen C.
• Application Number:
  US06/836,023
• Time in Patent Office: 959 Days
• Field of Search: 604/65, 604/67, 604/251, 604/253, 128/DIG. 12, 128/DIG. 13, 73/149, 417/384-389, 417/395
• US Class Current: 604/67
• CPC Class Codes: A61M 2005/1403 Flushing or purging
• CPC Class Codes: A61M 2205/15 Detection of leaks
• 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 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 5/365 Air detectors A61M5/1684 takes precedence; in extracorporeal blood circuits A61M1/3626
• CPC Class Codes: F04B 43/043 Micropumps
• CPC Class Codes: F16K 31/005 Piezoelectric benders
• CPC Class Codes: G01F 11/086 using an auxiliary pressure to cooperate with the diaphragm or bellows
• CPC Class Codes: G01P 13/0066 by using differences of pressure in the fluid
• CPC Class Codes: Y10S 128/12 Pressure infusion
• CPC Class Codes: Y10S 128/13 Infusion monitoring
• CPC Class Codes: Y10T 137/7782 With manual or external control for line valve
• CPC Class Codes: Y10T 137/7796 Senses inlet pressure
• CPC Class Codes: Y10T 137/88005 Biased valve

Abstract

A dispensing arrangement in a fluid line that isolates a region of fluid in the line from pressure effects in the line outside the region. A housing of measuring fluid surrounds the region so that changes in the measurement fluid pressure cause changes in the pressure of the original fluid in the region. Predetermined volume increments of the measurement fluid are displaced, causing changes in the original fluid pressure in the region which are measured by a pressure transducer. The dispensing arrangement also repetitively dispenses fluid into and out of the region in increments monitored by the pressure transducer.

Claims

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

dispensing means (i) for isolating a region of the first fluid in the line from effects of pressure in the line outside of the region, such region having an input and an output for the first fluid, and (ii) for repetitively dispensing into and out of the region increments of first fluid, whereby such dispensing may cause changes in pressure of the first fluid in the region;

pressure measurement means for measuring changes in pressure of the first fluid in the region;

measurement fluid housing means for housing a measurement fluid in relation to the region such that a change in the measurement fluid pressure causes a change in the first fluid pressure in the region;

displacement means for repetitively displacing predetermined volume increments of measurement fluid, whereby the resulting changes in first fluid pressure are measured by the pressure measurement means;

control means, in communication with the pressure measurement means, the displacement means, and the dispensing means, for causing the dispensing means to dispense first fluid in increments that are calibrated by the displacement means and monitored by the pressure measurement means.

2. A system according to claim 1, wherein (i) the dispensing means includes an input valve at the first fluid input to the region and an output valve at the first fluid output from the region and (ii) the measurement fluid is air.

3. A system according to claim 2, wherein the measurement fluid housing means includes a drip chamber through which the first fluid flows and the upper region of which is in communication with the displacement means.

4. A system according to claim 2, (i) wherein the measurement fluid housing means includes a substantially airtight housing around the region, such housing in communication with the displacement means, and (ii) further comprising a flexible enclosure, within the housing, for containing the first fluid in the region.

5. A system according to claim 3, wherein the control means includes means for causing the dispensing means to dispense first fluid in the same increments of volume as displaced by the displacement means.

6. A system according to claim 4, wherein the control means includes means for causing the dispensing means to dispense first fluid in the same increments of volume as displaced by the displacement means.

7. A system according to claim 5, wherein the control means includes means for causing the first fluid in the region to have an average line pressure regulated at a desired amount lying in the range of 1/2 to 10 lbs. per square inch.