Liquid gaging system compatible with multiple characterization of each sensor

• US 4,373,390 A
• Filed: 01/28/1982
• Issued: 02/15/1983
• Est. Priority Date: 05/14/1980
• Status: Expired due to Term

• Current Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Original Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Inventors: Dougherty, William R., van Dyke, Martin J., Colby, Dwight D.
• Primary Examiner(s): Kreitman, Stephen A.
• Application Number:
  US06/343,636
• Time in Patent Office: 383 Days
• Field of Search: 73/304 C, 364/442, 364/509, 318/642, 324/61 R, 324/61 P
• US Class Current: 73/304.00C
• CPC Class Codes: G01F 23/263 by measuring variations in capacitance of capacitors

Abstract

A liquid gaging system comprising a sensor for providing a liquid measurement signal related to a liquid depth at a particular location in a tank. The system further comprises storage apparatus for storing data including characterization parameters, each parameter being based on tank shape and volume and on sensor location, each parameter defining a relationship between a liquid depth and a value related to a liquid quantity. The system also includes determining apparatus for determining a value related to a liquid quantity in the tank based on the liquid measurement signal and the data, the determining apparatus being connected to the sensor and to the storage apparatus.

Claims

1. A liquid gaging system comprising:

a sensor for providing a liquid measurement signal related to a liquid depth at a particular location in a tank;

storage means for storing data including characterization parameters, the storage means comprising means for storing look up tables, there being a first look up table for storing at least a first parameter and a second look up table for storing at least a second parameter, each parameter being based on tank shape and volume and on sensor location, each parameter defining a relationship between a liquid depth and a volume related to a liquid quantity; and

determining means for selecting an appropriate look up table and for determining a value related to a liquid quantity in the tank based on the liquid measurement signal and the data, the determining means being connected to the sensor and to the storage means.

2. The apparatus of claim 1 wherein the determining means comprises means for selecting an appropriate look up table by monitoring a physical condition related to an orientation that the liquid occupies in the tank.

3. The apparatus of claim 1 or 2 wherein the sensor comprises a capacitive probe, the liquid measurement signal provided by the probe being a wetted sensor length signal related to the portion of the probe immersed in a liquid, the portion so immersed being a wetted sensing length.

4. The apparatus of claim 3 wherein the capacitive probe has an essentially uniform capacitance per unit length.

5. The apparatus of claim 4 wherein:

P1 the capacitive probe produces a wetted sensor length signal which is also dependent upon the dielectric constant of the liquid;

the apparatus further comprises a dielectric sensor for providing a capacitive signal related to the dielectric constant of the liquid; and

the determining means comprises means for determining a value related to a liquid quantity wherein the value is also based on the capacitive signal, the determining means also being connected to the dielectric sensor.

6. The apparatus of claim 1 wherein:

the determining means comprises means for selecting an appropriate look up table by identifying a look up table used in a previous value determination whenever a previous value is available and by identifying a look up table containing predetermined data whenever the system is initialized and a previous value determination is not available, each look up table containing data which will yield values that meet a specified system accuracy within a predetermined range as well as data which will yield values outside the predetermined range and not meeting the specified system accuracy, an appropriate look up table being subsequently selected if a value outside the predetermined range is determined.

7. The apparatus of claim 6 wherein the sensor comprises a capacitive probe, the liquid measurement signal provided by the probe being a wetted sensor length signal related to the portion of the probe immersed in a liquid, the portion so immersed being a wetted sensing length.

8. The apparatus of claim 7 wherein the capacitive probe has an essentially uniform capacitance per unit length.

9. The apparatus of claim 8 wherein:

the capacitive probe produces a wetted sensor length signal which is also dependent upon the dielectric constant of the liquid;

the apparatus further comprises a dielectric sensor for providing a capacitive signal related to the dielectric constant of the liquid; and

the determining means comprises means for determining a value related to a liquid quantity wherein the value is also based on the capacitive signal, the determining means also being connected to the dielectric sensor.

10. The apparatus of claim 1 wherein the system is for an aircraft and wherein the determining means comprises means for selecting an appropriate look up table based on whether the aircraft is in the air or on the ground.

11. The apparatus of claim 10 wherein the sensor comprises a capacitive probe, the liquid measurement signal provided by the probe being a wetted sensor length signal related to the portion of the probe immersed in a liquid, the portion so immersed being a wetted sensing length.

12. The apparatus of claim 11 wherein the capacitive probe has an essentially uniform capacitance per unit length.

13. The apparatus of claim 12 wherein:

the capacitive probe produces a wetted sensor length signal which is also dependent upon the dielectric constant of the liquid;

the apparatus further comprises a dielectric sensor for providing a capacitive signal related to the dielectric constant of the liquid; and

the determining means comprises means for determining a value related to a liquid quantity wherein the value is also based on the capacitive signal, the determining means also being connected to the dielectric sensor.

14. The apparatus of claim 1 wherein the storage means comprises means for storing characterization parameters based on a physical condition related to an orientation of a liquid surface in the tank.

15. The apparatus of claim 1 wherein the storage means comprises means for storing characterization parameters based on an orientation of the tank.

16. The apparatus of claim 1 wherein the system is for an aircraft and wherein the storage means comprises means for storing characterization parameters based on an attitude of the aircraft.

17. The apparatus of claim 14, 15, or 16 wherein the sensor comprises a capacitive probe, the liquid measurement signal provided by the probe being a wetted sensor length signal related to the portion of the probe immersed in a liquid, the portion so immersed being a wetted sensing length.

18. The apparatus of claim 17 wherein the capacitive probe has an essentially uniform capacitance per unit length.

19. The apparatus of claim 18 wherein:

the capacitive probe produces a wetted sensor length signal which is also dependent upon the dielectric constant of the liquid;

the apparatus further comprises a dielectric sensor for providing a capacitive signal related to the dielectric constant of the liquid; and

the determining means comprises means for determining a value related to a liquid quantity wherein the value is also based on the capacitive signal, the determining means also being connected to the dielectric sensor.

20. The apparatus of claim 1 wherein the storage means comprises means for storing characterization parameters wherein each parameter defines a volume increment related to a predetermined increment of liquid depth.

21. The apparatus of claim 1 wherein the sensor comprises a capacitive probe, the liquid measurement signal provided by the probe being a wetted sensor length signal related to the portion of the probe immersed in a liquid, the portion so immersed being a wetted sensing length.

22. The apparatus of claim 21 wherein:

the capacitive probe produces a wetted sensor length signal which is also dependent upon the dielectric constant of the liquid;

the apparatus further comprises a dielectric sensor for providing a capacitive signal related to the dielectric constant of the liquid; and

the determining means comprises means for determining a value related to a liquid quantity wherein the value is also based on the capacitive signal, the determining means also being connected to the dielectric sensor.

23. The apparatus of claim 21 wherein the capacitive probe has an essentially uniform capacitance per unit length.

24. The apparatus of claim 23 wherein:

the capacitive probe produces a wetted sensor length signal which is also dependent upon the dielectric constant of the liquid;

the apparatus further comprises a dielectric sensor for providing a capacitive signal related to the dielectric constant of the liquid; and

the determining means comprises means for determining a value related to a liquid quantity wherein the value is also based on the capacitive signal, the determining means also being connected to the dielectric sensor.

25. A liquid gaging system comprising:

a plurality of sensors, each sensor providing a liquid measurement signal relating to a liquid depth at a particular location in a tank;

storage means for storing data including characterization parameters, each parameter relating to a particular sensor, each parameter being based on tank shape and volume and on sensor location, each parameter defining a relationship between a liquid depth and a value related to a liquid quantity; and

determining means for determining a value related to a liquid quantity in the tank based on the liquid measurement signals and the data, the determining means being connected to the storage means, there being means for connecting the determining means to the sensors.

26. The apparatus of claim 25 wherein:

the storage means comprises means for storing look up tables, there being for each sensor a first look up table for storing at least a first parameter and a second look up table for storing at least a second parameter; and

the determining means comprises selection means for selecting an appropriate look up table corresponding to a particular sensor.

27. The apparatus of claim 26 wherein the selection means comprises means for selecting an appropriate look up table by monitoring a physical condition related to an orientation that the liquid occupies in the tank.

28. The apparatus of claim 26 or 27 wherein at least one of the sensors comprises a capacitive probe, the liquid measurement signal provided by the probe being a wetted sensor length signal related to the portion of the probe immersed in a liquid, the portion so immersed being a wetted sensing length.

29. The apparatus of claim 28 wherein the capacitive probe has an essentially uniform capacitance per unit length.

30. The apparatus of claim 29 wherein:

the capacitive probe produces a wetted sensor length signal which is also dependent upon the dielectric constant of the liquid;

the apparatus further comprises a dielectric sensor for providing a capacitive signal related to the dielectric constant of the liquid; and

the determining means comprises means for determining a value related to a liquid quantity wherein the value is also based on the capacitive signal, the determining means also being connected to the dielectric sensor.

31. The apparatus of claim 26 wherein:

the selection means comprises means for selecting the appropriate look up table by identifying a look up table corresponding to a particular sensor and used in a previous value determination whenever a previous value determination is available and by identifying a look up table corresponding to the particular sensor and containing predetermined data whenever the system is initialized and a previous value determination is not available, each look up table containing data which will yield values that meet a specified system accuracy within a predetermined range as well as data which will yield values outside the predetermined range and not meeting the specified system accuracy, an appropriate look up table being subsequently selected if a value outside the predetermined range is determined.

32. The apparatus of claim 31 wherein at least one of the sensors comprises a capacitive probe, the liquid measurement signal provided by the probe being a wetted sensor length signal related to the portion of the probe immersed in a liquid, the portion so immersed being a wetted sensing length.

33. The apparatus of claim 32 wherein the capacitive probe has an essentially uniform capacitance per unit length.

34. The apparatus of claim 33 wherein:

the capacitive probe produces a wetted sensor length signal which is also dependent upon the dielectric constant of the liquid;

the apparatus further comprises a dielectric sensor for providing a capacitive signal related to the dielectric constant of the liquid; and

the determining means comprises means for determining a value related to a liquid quantity wherein the value is also based on the capacitive signal, the determining means also being connected to the dielectric sensor.

35. The apparatus of claim 26 wherein the system is for an aircraft and wherein the selection means comprises means for selecting based on whether the aircraft is in the air or on the ground.

36. The apparatus of claim 35 wherein at least one of the sensors comprises a capacitive probe, the liquid measurement signal provided by the probe being a wetted sensor length signal related to the portion of the probe immersed in a liquid, the portion so immersed being a wetted sensing length.

37. The apparatus of claim 36 wherein the capacitive probe has an essentially uniform capacitance per unit length.

38. The apparatus of claim 37 wherein:

the capacitive probe produces a wetted sensor length signal which is also dependent upon the dielectric constant of the liquid;

the apparatus further comprises a dielectric sensor for providing a capacitive signal related to the dielectric constant of the liquid; and

the determining means comprises means for determining a value related to a liquid quantity wherein the value is also based on the capacitive signal, the determining means also being connected to the dielectric sensor.

39. The apparatus of claim 25 wherein the storage means comprises means for storing characterization parameters based on a physical condition related to an orientation of a liquid surface in a tank.

40. The apparatus of claim 25 wherein the storage means comprises means for storing characterization parameters based on an orientation of the tank.

41. The apparatus of claim 25 wherein the system is for an aircraft and wherein the storage means comprises means for storing characterization parameters based on an attitude of the aircraft.

42. The apparatus of claim 39, 40, or 41 wherein at least one of the sensors comprises a capacitive probe, the liquid measurement signal provided by the probe being a wetted sensor length signal related to the portion of the probe immersed in a liquid, the portion so immersed being a wetted sensing length.

43. The apparatus of claim 42 wherein the capacitive probe has an essentially uniform capacitance per unit length.

44. The apparatus of claim 43 wherein:

the capacitive probe produces a wetted sensor length signal which is also dependent upon the dielectric constant of the liquid;

the apparatus further comprises a dielectric sensor for providing a capacitive signal related to the dielectric constant of the liquid; and

the determining means comprises means for determining a value related to a liquid quantity wherein the value is also based on the capacitive signal, the determining means also being connected to the dielectric sensor.

45. The apparatus of claim 25 wherein the storage means comprises means for storing characterization parameters wherein each parameter defines a volume increment related to a predetermined increment of liquid depth.

46. The apparatus of claim 25 wherein at least one of the sensors comprises a capacitive probe, the liquid measurement signal provided by the probe being a wetted sensor length signal related to the portion of the probe immersed in a liquid, the portion so immersed being a wetted sensing length.

47. The apparatus of claim 46 wherein:

the capacitive probe produces a wetted sensor length signal which is also dependent upon the dielectric constant of the liquid;

the apparatus further comprises a dielectric sensor for providing a capacitive signal related to the dielectric constant of the liquid; and

the determining means comprises means for determining a value related to a liquid quantity wherein the value is also based on the capacitive signal, the determining means also being connected to the dielectric sensor.

48. The apparatus of claim 46 wherein the capacitive probe has an essentially uniform capacitance unit length.

49. The apparatus of claim 48 wherein:

the capacitive probe produces a wetted sensor length signal which is also dependent upon the dielectric constant of the liquid;

the apparatus further comprises a dielectric sensor for providing a capacitive signal related to the dielectric constant of the liquid; and

the determining means comprises means for determining a value related to a liquid quantity wherein the value is also based on the capacitive signal, the determining means also being connected to the dielectric sensor.