Flow and pressure sensor for harsh fluids

• US 6,681,623 B2
• Filed: 10/30/2001
• Issued: 01/27/2004
• Est. Priority Date: 10/30/2001
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Bonne, Ulrich, Speldrich, Jamie
• Primary Examiner(s): RAEVIS, ROBERT R
• Application Number:
  US10/011,932
• Publication Number:
  US 20030079542A1
• Time in Patent Office: 819 Days
• Field of Search: 732/02, 732/025, 732/03, 737/06, 738/615--86
• US Class Current: 73/202
• CPC Class Codes: G01F 1/40 Details of construction of the flow constriction devices
• CPC Class Codes: G01F 1/6842 with means for influencing the fluid flow
• CPC Class Codes: G01F 15/12 Cleaning arrangements; Filters
• CPC Class Codes: G01F 5/00 Measuring a proportion of the volume flow
• CPC Class Codes: G01F 5/005 by measuring pressure or differential pressure, created by the use of flow constriction

Abstract

Methods and systems for preventing degradation of a sensor exposed to a harsh fluid, such as one that might corrode or be exposed to radioactive contaminants, live pathogens, freezing temperatures, overheating, particle deposition or condensable vapors is disclosed. An auxiliary purge stream of comparatively clean fluid or purge fluid is utilized, which flows past the sensor in opposition to the harsh fluid, thereby preventing the harsh fluid from contacting and degrading the sensor. The clean fluid itself may comprise a purge gas, such as clean, dry air, or a liquid that is compatible with the composition of the harsh fluid. The flow and pressure of the clean fluid can be adjusted utilizing one or more supply regulator valves.

Claims

1. A method for preventing contamination of a sensor exposed to a harsh fluid as a result of fluid flow through a bypass channel integrated with a main channel and a restricted portion thereof, said method comprising the steps of:

conducting said harsh fluid through said main channel and said restricted portion thereof, wherein a portion of said harsh fluid contacts said sensor through said bypass channel; and

introducing an auxiliary flow of a purge fluid, wherein said purge fluid is compatible with a composition of said harsh fluid such that said purge fluid flows past said sensor in opposition to said harsh fluid, thereby preventing said harsh fluid from contacting and degrading said sensor.

2. The method of claim 1 further comprising the step of:

configuring said auxiliary flow of purge fluid to comprise an auxiliary purge stream to prevent contamination of said sensor.

3. The method of claim 1 wherein said purge fluid comprises a purge gas compatible with said composition of said harsh fluid.

4. The method of claim 1 further comprising the step of:

adjusting said auxiliary flow of said purge fluid utilizing at least one regulator valve.

5. The method of claim 1 further comprising the step of:

adjusting a pressure associated with said flow of said purge fluid utilizing at least one regulator valve.

6. The method of claim 1 further comprising the step of:

applying said auxiliary flow of said purge fluid to flow past said sensor in opposition to said harsh fluid, such that said purge fluid flows symmetrically.

7. The method of claim 1 wherein said sensor comprises a flow sensor.

8. The method of claim 1 wherein said sensor comprises a microsensor.

9. The method of claim 1 further comprising the step of:

configuring said sensor as a unidirectional sensor; and

thereafter converting said unidirectional sensor to a bi-directional sensor by adding a non-symmetrical flow bias to a plurality of associated ports.

10. A method for preventing contamination of a flow sensor exposed to a harsh fluid as a result of fluid flow through a bypass channel integrated with a main channel and a restricted portion thereof, said method comprising the steps of:

conducting said harsh fluid through said main channel and said restricted portion thereof, wherein a portion of said harsh fluid contacts said flow sensor through said bypass channel;

introducing a stream of purge gas compatible with a composition of said harsh fluid such that said purge gas flows past said sensor in opposition to said harsh fluid; and

adjusting a flow and pressure of said purge gas utilizing at least one regulator valve, thereby preventing said harsh fluid from contacting and degrading said flow sensor.

11. A method for preventing contamination of a flow sensor exposed to a harsh fluid as a result of fluid flow through a bypass channel integrated with a main channel and a restricted portion thereof, said method comprising the steps of:

conducting said harsh fluid through said main channel and said restricted portion thereof, wherein a portion of said harsh fluid comes into contact with said flow sensor through said bypass channel;

introducing a stream of purge gas compatible with a composition of said harsh fluid such that said purge gas flows past said sensor in opposition to said harsh fluid;

applying said stream of purge gas to flows symmetrically; and

adjusting a flow and pressure of said purge gas utilizing at least one regulator valve, thereby preventing said harsh fluid from contacting and degrading said flow sensor.

12. A system for preventing contamination of a sensor exposed to a harsh fluid as a result of fluid flow through a bypass channel integrated with a main channel and a restricted portion thereof, said system comprising:

said harsh fluid conducted through said main channel and said restricted portion thereof, wherein a portion of said harsh fluid comes into contact with said sensor through said bypass channel; and

an auxiliary flow of purge fluid that is compatible with a composition of said harsh fluid such that said purge fluid flows past said sensor in opposition to said harsh fluid, thereby preventing said harsh fluid from contacting and degrading said sensor.

13. The system of claim 12 wherein said auxiliary flow of purge fluid comprises an auxiliary purge stream to prevent contamination of said sensor.

14. The system of claim 12 wherein said purge fluid comprises a purge gas compatible with said composition of said harsh fluid.

15. The system of claim 12 wherein said auxiliary flow of purge fluid is adjustable utilizing at least one regulator valve.

16. The system of claim 12 wherein a pressure associated with said flow of purge fluid is adjustable utilizing at least one regulator valve.

17. The system of claim 12 wherein said auxiliary flow of purge fluid is introduced to flow past said sensor in opposition to said harsh fluid, such that said purge fluid flows symmetrically.

18. The system of claim 12 wherein said sensor comprises a flow sensor.

19. The system of claim 12 wherein said sensor comprises a microsensor.

20. The system of claim 12 wherein said sensor comprises a unidirectional sensor convertible to a bi-directional sensor by adding a non-symmetrical flow bias to associated ports.

21. A system for preventing contamination of a flow sensor exposed to a harsh fluid as a result of fluid flow through a bypass channel integrated with a main channel and a restricted portion thereof, said system comprising:

said harsh fluid conducted through said main channel and said restricted portion thereof, wherein a portion of said harsh fluid comes into contact with said flow sensor through said bypass channel;

a stream of purge gas compatible with a composition of said harsh fluid wherein said purge gas flows past said sensor in opposition to said harsh fluid; and

wherein a flow and pressure of said purge gas is adjustable utilizing at least one regulator valve, thereby preventing said harsh fluid from contacting and degrading said flow sensor.

22. A system for preventing contamination of a microsensor exposed to a harsh fluid as a result of fluid flow through a bypass channel integrated with a main channel and a restricted portion thereof, said system comprising:

said harsh fluid conducted through said main channel and said restricted portion thereof, wherein a portion of said harsh fluid comes into contact with said microsensor through said bypass channel;

a stream of purge gas compatible with a composition of said harsh fluid wherein said purge gas flows symmetrically past said sensor in opposition to said harsh fluid; and

wherein a flow and pressure of said purge gas is adjustable utilizing at least one regulator valve, thereby preventing said harsh fluid from contacting and degrading said microsensor.