Fluid tank with integral fluid quantity gauging

• US 5,386,736 A
• Filed: 05/02/1994
• Issued: 02/07/1995
• Est. Priority Date: 10/27/1992
• Status: Expired due to Term

• Current Assignee: Simmonds Precision Products, Inc. (Rtx Corporation)
• Original Assignee: Simmonds Precision Products, Inc. (Rtx Corporation)
• Inventors: Spillman, William B. Jr.
• Primary Examiner(s): GUTIERREZ, DIEGO F
• Application Number:
  US08/237,944
• Time in Patent Office: 281 Days
• Field of Search: 73/291, 73/301, 73/299, 73/DIG. 10, 73/149, 73/865, 73/296, 364/509
• US Class Current: 73/865
• CPC Class Codes: G01F 23/18 Indicating, recording or alarm devices actuated electrically
• CPC Class Codes: G01F 23/804 containing circuits handling parameters other than liquid level
• CPC Class Codes: G01G 19/07 for weighing aircraft
• CPC Class Codes: Y10S 73/10 instrument mechanisms with acceleration compensation

Abstract

A gauging system for a fluid tank includes means for determining fluid pressure data for the tank; means for determining acceleration data of the tank; and means for determining quantity of fluid in the tank as a function of the pressure and acceleration data. A method for determining quantity of fluid in a tank is also provided and includes the steps of:

a. determining an orientation vector for each of a plurality of sensing areas of the tank;

b. producing an output corresponding to pressure of the fluid on each of the respective sensing areas;

c. determining an acceleration vector of the tank; and

d. calculating quantity of fluid in the tank as a function of the pressure output signals, the orientation vectors and the acceleration vector.

Claims

1. A system for determining mass of liquid held in a container under a varying acceleration, comprising a plurality of force-responsive detectors disposed correspondingly at a like plurality of planar surface areas that define the container, each of said detectors sensing the total fluid force exerted across its respective surface area and producing a first electrical signal representative thereof;

an accelerometer for sensing said varying acceleration of the container and producing a second electrical signal corresponding thereto; and

processing circuit means for receiving said first and second electrical signals and modifying each of said first electrical signals by both a corresponding predetermined surface area orientation signal and said second electrical signal;

said processing means combining the modified first electrical signals to produce a signal representative of the mass of liquid in the container.

2. The system of claim 1 wherein each of said detectors comprises a force sensitive material lining its respective surface area of the container.

3. The system of claim 1 wherein said second electrical signal corresponds to a three-axis vector representation of said varying acceleration.

4. The system of claim 3 wherein each of said surface areas of the container has a predetermined orientation vector normal to the surface and defined with respect to said three axes.

5. The system of claim 4 wherein said processing circuit means calculates the vector dot product of said second electrical signal with each of said orientation vectors.

6. The system of claim 5 wherein said processing circuit means further calculates the square of the magnitude of said second electrical signal, divides each of said vector dot products by said square magnitude value to produce a ratio, and multiplies each ratio by its corresponding first electrical signal to produce a plurality of quantity data, with the sum of said quantity data corresponding to the mass of liquid in the container.

7. The system according to claim 1 wherein each detector comprises a force detecting element distributed substantially across its respective planar surface area;

said element producing an electrical signal in response to the force exerted thereon by the container fluid.

8. A system for determining mass of liquid held in a tank under an acceleration of varying direction comprising:

a number of sensors disposed correspondingly at a number of predetermined planar surface areas that define the tank;

each sensor sensing the total force on its respective surface area and producing a first signal indicative thereof;

means for determining variations in magnitude and direction of the tank acceleration vector; and

a processor circuit including means for receiving the first signals and for modifying each of the first signals respectively by said determined acceleration vector relative to respective orientation signals, each orientation signal being based on a vector normal to each corresponding planar surface area, and for summing all said modified first signals to produce a signal representative of the mass of the liquid in the tank.

9. The system of claim 8 wherein said processor circuit comprises memory means for storing said orientation signals for each respective surface area for use by said processor to modify said first signals.

10. The system of claim 9 wherein said processor circuit further comprises means for digitizing said first signals and digitally modifying said first signals with said orientation signals.

11. The system of claim 10 wherein said processor circuit further comprises means for digitizing acceleration signals received from a three-axis accelerometer, said acceleration signals corresponding to an acceleration vector for the tank.

12. The system of claim 11 wherein said processor circuit modifies each of said first signals by first computing a value that corresponds to the vector dot product of said acceleration vector and orientation vector for the corresponding surface area.