Claims
- 1. A method of making a sensor for detecting a liquid in a flexible conduit comprising the steps of:
- providing a flexible conduit means;
- forming a loop of the flexible conduit means said loop having two legs, and positioning said loop in cooperation with a peristaltic pump;
- mounting said legs in a fixture wherein a strain-sensitive film in the fixture is positioned adjacent and in contact with one of said legs to sense pressure within the flexible conduit means; and
- providing electrical connections to the strain-sensitive film adapted to sense periodic strains whereby pulses of pressure transmitted through the flexible conduit means may be detected.
- 2. A method of making a sensor according to claim 1 in which the step of mounting a flexible conduit means includes the step of mounting a flexible tube and a strain-sensitive film in the fixture wherein the strain-sensitive film and the flexible tube are supported at a location adjacent to a conduit support means whereby at least a portion of the strain-sensitive film is in contact with the conduit when the fixture and conduit are assembled.
- 3. A method of making a sensor according to claim 2 including the step of permitting:
- sufficient expansion of the conduit to create strain of an amplitude to permit discrimination of signal from noise wherein said strain-sensitive film is partly stretched in the fixture whereby liquid pumped through the conduit may be detected.
- 4. A method of making a sensor according to claim 1 including the step of permitting sufficient expansion of the conduit in an opening having a depth of at least the thickness of the conduit plus one-thousandth of an inch.
- 5. A method of making a sensor according to claim 1 wherein said strain-sensitive film is pre-stretched by the conduit during installation of the conduit into a means for receiving said conduit.
- 6. A method of making a sensor according to claim 1 wherein after installation said strain-sensitive film has contact with the conduit of at least one-sixteenth of a square inch.
- 7. A method of making a sensor according to claim 1 including the step of mounting the fixture and a pump at a distance from each other sufficiently close to detect the difference in amplitude of strain when liquid reaches a predetermined point from amplitude before it reaches the predetermined point.
- 8. A method of making a sensor according to claim 1 in which the strain sensitive film is mounted at a distance no greater than 18 inches from a pump.
- 9. A method of making a sensor according to claim 1 in which the strain-sensitive film is mounted on the inlet side of a pump.
- 10. A method of making a sensor according to claim 1 in which the electrical connections to the strain-sensitive film are connected to a programmable computer.
- 11. A method of making a sensor according to claim 1 including the step of connecting the strain-sensitive film to a programmable computer means for predicting the number of force pulses transmitted through the flexible conduit means to the sensor before sensing the liquid; said programmable computer means having a statistical database.
- 12. A method of making a sensor according to claim 1 wherein a programmable computer means is programmed to determine which pulses are sensed; said programmable computer means being programmed to count slugs of liquid only when followed by a flow of liquid.
- 13. A method of making a sensor according to claim 1 including the step of determining when a predetermined volume of liquid has been pumped to a container; counting pulses applied to said electrical connections, and reading from a look-up table the volume of liquid deposited corresponding to said counted pulses.
RELATED CASES
This application is a division of application Ser. No. 08/430,155, filed Apr. 26, 1995, which is a divisional application of U.S. application Ser. No. 07/807,200, filed Dec. 16, 1991, now U.S. Pat. No. 5,401,139 which is a divisional of U.S. application Ser. No. 07/474,154 filed Feb. 2, 1990, now U.S. Pat. No. 5,125,801 in the names of Frederick Alan Nabity, Paul George Wright, Raymond Hulinsky and Douglas Timothy Carson for PUMPING SYSTEM and assigned to the same assignee as this application.
US Referenced Citations (3)
Number |
Name |
Date |
Kind |
4216403 |
Krempl et al. |
Aug 1980 |
|
4304126 |
Yelke |
Dec 1981 |
|
4391147 |
Krempl et al. |
Jul 1983 |
|
Divisions (3)
|
Number |
Date |
Country |
Parent |
430155 |
Apr 1995 |
|
Parent |
807200 |
Dec 1991 |
|
Parent |
474154 |
Feb 1990 |
|