AIRCRAFT FLUID GAUGING TECHNIQUES USING PRESSURE MEASUREMENTS AND OPTICAL SENSORS

• US 20150100253A1
• Filed: 10/09/2014
• Published: 04/09/2015
• Est. Priority Date: 10/09/2013
• Status: Abandoned Application

• Current Assignee: Parker-Hannifin Corporation
• Original Assignee: Parker-Hannifin Corporation
• Inventors: Wood, Stanley, Austerlitz, Howard P., Bueter, Ronald W., Boyd, Lewis J.
• Application Number:
  US14/510,288
• Publication Number:
  US 20150100253A1
• Time in Patent Office: Days
• US Class Current: 702/55
• CPC Class Codes: G01F 22/00 Methods or apparatus for measuring volume of fluids or fluent solid material, not otherwise provided for
• CPC Class Codes: G01F 23/14 by measurement of pressure
• CPC Class Codes: G01F 23/18 Indicating, recording or alarm devices actuated electrically

Abstract

A fluid level measurement system includes a first pressure sensor disposed inside a fluid tank at a first elevation relative to a height axis of the fluid tank, and a second pressure sensor disposed inside the fluid tank at a second elevation relative to the height axis of the fluid tank, the second elevation different from the first elevation. The first pressure sensor and the second pressure sensor are configured to provide a signal indicative of a sensed pressure, and fluid height is calculated from the difference in sensed pressure between the first and second pressure sensors relative to the sensed pressure of either the first or the second pressure sensor.

Claims

1. A fluid level measurement system, comprising:

a first pressure sensor disposed inside a fluid tank at a first elevation relative to a height axis of the fluid tank;

a second pressure sensor disposed inside the fluid tank at a second elevation relative to the height axis of the fluid tank, the second elevation different from the first elevation,

wherein the first pressure sensor and the second pressure sensor are configured to provide a signal indicative of a sensed pressure, and fluid height is calculated from the difference in sensed pressure between the first and second pressure sensors.

2. The fluid level measurement system according to claim 1, wherein fluid height is calculated from the difference in sensed pressure between the first and second pressure sensors relative to the sensed pressure of either the first or the second pressure sensor.

3. The fluid level measurement system according to claim 1, further comprising a controller communicatively coupled to the first pressure sensor and the second pressure sensor to receive the signal indicative of the sensed pressure from each sensor, the controller configured to calculate the fluid level in the fluid tank based on the difference in sensed pressures of the first and second pressure sensors.

4. The fluid level measurement system according to claim 1, further comprising the fluid tank.

5. The fluid level measurement system according to claim 1, wherein the first pressure sensor is spaced a first known distance apart from the second pressure sensor along an axis parallel to the height axis.

6. The fluid level measurement system according to claim 5, further comprising a third pressure sensor disposed inside the fluid tank and at a third elevation relative to a height axis of the fluid tank, the third pressure sensor spaced a second known distance apart from the first pressure sensor and a third known distance from the second pressure sensor,

wherein the controller is configured to calculate a location of a fluid surface plane in the fluid tank based on the sensed pressure of the first, second and third pressure sensors and the first known distance, the second known distance, and the third known distance.

7. The fluid level measurement system according to claim 6, wherein the controller is configured to calculate at least one of a pitch angle of a fluid surface or a roll angle of the fluid surface relative to a reference surface of the fluid tank based on the first known distance, the second known distance, and the third known distance.

8. The fluid level measurement system according to claim 1, wherein the first pressure sensor and the second pressure sensor are arranged on a common support member of an integrated pressure assembly.

9. The fluid level measurement system according to claim 1, wherein at least one of the first pressure sensor or the second pressure sensor comprises an optical pressure sensor.

10. The fluid level measurement system of claim 9, wherein the controller is optically coupled to at least one of the first pressure sensor or the second pressure sensor.

11. The fluid level measurement system according to claim 1, wherein at least one of the first pressure sensor or the second pressure sensor comprises a passive optical pressure sensor.

12. The fluid level measurement system according to claim 1, wherein at least one of the first pressure sensor or the second pressure sensor comprises at least one of a passive Fabry-Perot optical pressure sensor or a passive Fiber Bragg Grating optical pressure sensor.

13. The fluid level measurement system according to claim 1, wherein at least one of the first pressure sensor or the second pressure sensor comprises a differential pressure sensor having a first port fluidically connected to an ullage portion of the fluid tank.

14. The fluid level measurement system of claim 13, further comprising a gas-filled equalizer arranged within the fluid tank and fluidically connected to an ullage portion of the fluid tank, wherein the first port of each differential pressure sensor is fluidically connected to the gas-filled equalizer.

15. The fluid level measurement system of claim 14, wherein the gas-filled equalizer comprises an outer surface and a portion of the outer surface includes a flexible membrane, further comprising a fourth pressure sensor disposed inside the tank, wherein the fourth pressure sensor is a differential pressure sensor having a first port fluidically connected to the ullage portion of the fluid tank and a second port fluidically connected to the gas-filled equalizer.

16. An aircraft comprising the fluid level measurement system according to claim 1.

17. A method of measuring a fluid level in a fluid tank, the fluid tank including a first pressure sensor disposed inside the fluid tank at a first elevation relative to a height axis of the fluid tank and a second pressure sensor disposed inside the fluid tank at a second elevation relative to the height axis of the fluid tank, the second elevation different from the first elevation, the method comprising:

using the first pressure sensor to measure a first pressure value;

using the second pressure sensor to measure a second pressure value; and

calculating the fluid level of the fluid in the tank based on a difference in pressure between the first measured pressure value and the second measured pressure value.

18. The method according to claim 17, wherein calculating the fluid leveled comprises calculating the fluid level from the difference in sensed pressure between the first and second pressure sensors relative to the sensed pressure of either the first or the second pressure sensor.

19. The method according to claim 17, wherein calculating the fluid level includes using the equation

20. The method according to claim 17, wherein using the first and second pressure sensors includes using first and second differential pressure sensors, respectively, to measure the first and second pressure values.

21. The method according to claim 20, further comprising coupling the first and second pressure sensors to a pressure equalizer, the pressure equalizer fluidically coupled to an ullage of the fluid tank.

22. A method of measuring a fluid level in a fluid tank, the fluid tank including a first pressure sensor disposed inside the fluid tank, a second pressure sensor disposed inside the fluid tank and horizontally spaced apart from the first pressure sensor by a first known distance, and a third pressure sensor disposed inside the fluid tank and horizontally spaced apart from the first pressure sensor by a second known distance and horizontally spaced apart from the second pressure sensor by a third known distance, the method comprising:

determining a first fluid level height based on a first pressure value obtained from the first pressure sensor;

determining a second fluid level height based on a second pressure value obtained from the second pressure sensor;

determining a third fluid level height based on a third pressure value obtained from the third; and

calculating a location of a fluid surface plane in the fluid tank based on the first, second and third fluid levels.

23. The method according to claim 22, further comprising calculating a pitch angle of the fluid surface relative to a reference surface of the fluid tank based on the first known distance, second known distance, and third known distance.

24. The method according to claim 23, further comprising calculating a roll angle of the fluid surface relative to a reference surface of the fluid tank based on the first known distance, second known distance, and third known distance.

25. The method according to claim 24, further comprising calculating a volume of fluid in the fluid tank based on a known geometry of the fluid tank, the fluid surface plane, the pitch angle, and the roll angle.