Liquid tank level measurement

Patent metadata

Field	Value
Publication number	US-11022477-B2
Application number	US-201816213575-A
Country	US
Kind code	B2
Filing date	Dec 7, 2018
Priority date	Dec 7, 2018
Publication date	Jun 1, 2021
Grant date	Jun 1, 2021

Abstract

An exemplary liquid tank level measurement system includes a tank having a wall, an accelerometer attached to the wall and configured to measure a vibration in the wall, and an instrument electronically connected to the accelerometer, the instrument configured to communicate a liquid level condition responsive to a vibration measurement received from the accelerometer.

First claim

What is claimed is:

1. An aircraft, the aircraft comprising:
an engine connected a gearbox to drive a rotor when the aircraft is operating, wherein the operating aircraft has an inherent forcing frequency;
the gearbox comprising a tank;
a lubricant in the tank;
an accelerometer attached to a wall of the tank and operable to measure the inherent forcing frequency in the wall; and
an instrument electronically connected to the accelerometer and operable to communicate a level of the lubricant in the tank responsive to a forcing frequency measurement received from the accelerometer.

2. The system of claim 1 , wherein the instrument is operable to communicate an alarm when the lubricant level is below a threshold level.

3. The system of claim 2 , wherein the alarm is an audible alarm.

4. The system of claim 1 , wherein the vibration measurement is along an axis normal to the wall.

5. The system of claim 1 , wherein the accelerometer consists of a single-axis accelerometer and the vibration measurement consists of a measurement along an axis normal to the wall.

6. The system of claim 1 , wherein the vibration measurement comprises a measurement along more than one axis.

7. The aircraft of claim 1 , wherein the accelerometer consists of a single-axis accelerometer.

8. The aircraft of claim 1 , wherein the accelerometer comprises a plurality of vertically separated accelerometers.

9. A method, comprising:
monitoring a lubricant level in an operating aircraft, the aircraft comprising an engine connected to a rotor through a gearbox, the gearbox comprising a lubricant tank;
measuring, with an accelerometer, a continuous forcing frequency of the operating aircraft in a wall of the lubricant tank; and
communicating the lubricant level in response to the measuring.

10. The method of claim 9 , wherein the lubricant level is communicated to a flight computer.

11. The method of claim 9 , wherein the accelerometer includes two or more vertically separated accelerometers.

12. The method of claim 9 , wherein the communicating comprises communicating an alarm when the lubricant level is at or below a threshold level.

13. The method of claim 9 , wherein the communicating consists of communicating the lubricant level when it is at or below a threshold level.

14. The method of claim 13 , wherein the accelerometer includes two or more vertically separated accelerometers.

Assignees

• Bell Helicopter Textron Inc

Inventors

• Olson Eric Stephen

Classifications

• G01F23/0007

  for discrete indicating and measuring (G01F23/02 - G01F23/28 take precedence) · CPC title

• B64D37/02

  Tanks (tanks constructed integrally with aircraft wings B64C3/34) · CPC title

• B64C29/0033

  the propellers being tiltable relative to the fuselage · CPC title

• G01F23/2966

  making use of acoustical resonance or standing waves · CPC title

• B64D45/00

  Aircraft indicators or protectors not otherwise provided for · CPC title