ULTRASONIC LIQUID LEVEL MONITORING SYSTEM

• US 20100242593A1
• Filed: 03/25/2009
• Published: 09/30/2010
• Est. Priority Date: 03/25/2009
• Status: Active Grant

• Current Assignee: Schmitt Measurement Systems, Inc. (Schmitt Industries, Inc.)
• Original Assignee: Schmitt Measurement Systems, Inc. (Schmitt Industries, Inc.)
• Inventors: Staats, Christian N., Wegrzyn, Kenneth M., Lagergren, Peter J., Woltring, Kelvin L., Case, Wayne A.
• Granted Patent: US 8,104,341 B2
• Time in Patent Office: Days
• US Class Current: 73/290.V
• CPC Class Codes: G01D 21/00 Measuring or testing not otherwise provided for
• CPC Class Codes: G01D 5/48 using wave or particle radiation means G01D5/26 takes precedence
• CPC Class Codes: G01F 23/2962 Measuring transit time of reflected waves
• CPC Class Codes: G01F 23/804 containing circuits handling parameters other than liquid level

Abstract

An ultrasonic liquid level monitoring system includes an ultrasonic transducer unit that is externally mountable to a tank. An ultrasonic emitter may generate an ultrasonic beam and receive an echo of the ultrasonic beam off a liquid surface inside a tank. An acoustic lens is coupled to the ultrasonic emitter to shape the ultrasonic beam to compensate for lensing effects of the tank wall. An acoustic coupler may be disposed between the acoustic lens and the tank wall to improve the acoustic coupling between the ultrasonic emitter and the tank wall. The system determines a time-of-flight between generating the ultrasonic beam and receiving the echo. Using the time-of-flight and geometry of a tank, the system may calculate the liquid volume inside the tank. The time-of-flight may be transmitted via a satellite data link or a local data link. The local data link may further be used to configure and maintain the system.

Claims

1. An ultrasonic transducer unit externally mountable to a tank wall and operable to measure a liquid level inside a tank, comprising:

an emitter to generate an ultrasonic beam to pass through a tank wall and to receive an echo of the ultrasonic beam off a liquid surface inside the tank;

a transducer driver in electrical communication with the emitter;

an acoustic lens coupled to the emitter and configured to shape the ultrasonic beam and configured to diverge the ultrasonic beam and thereby provide a divergent ultrasonic beam after the ultrasonic beam passes through a tank wall; and

an acoustic coupler disposed adjacent the acoustic lens and configured to increase transmission of the ultrasonic beam to the interface with the tank wall.

2. The ultrasonic transducer unit of claim 1, wherein the acoustic coupler is complimentary to the curvature of the tank.

3. The ultrasonic transducer unit of claim 1, further comprising acoustically transparent media disposed between the acoustic coupler and the tank wall.

4. The ultrasonic transducer unit of claim 3, wherein the acoustically transparent media is silicone grease.

5. The ultrasonic transducer unit of claim 4, wherein the acoustically transparent media is silicone oil.

6. The ultrasonic transducer unit of claim 1, wherein the acoustic coupler comprises polyurethane.

7. The ultrasonic transducer unit of claim 6, wherein the hardness of the polyurethane is in the range of about 20 to about 80 durometer, shore A.

8. The ultrasonic transducer unit of claim 6, wherein the hardness of the polyurethane is about 55 durometer, shore A.

9. The ultrasonic transducer unit of claim 1, further comprising a plurality of mounting magnets connected to the ultrasonic transducer and operable to mount the ultrasonic transducer to the exterior of the tank wall.

10. The ultrasonic transducer unit of claim 9, wherein the mounting magnets are adjustable such that the face of each mounting magnet is substantially parallel to the tank wall when the transducer unit is mounted to the tank.

11. The ultrasonic transducer unit of claim 10, wherein the mounting magnets are each connected to the ultrasonic transducer using a spring.

12. The ultrasonic transducer unit of claim 11, wherein the springs are movable between a first position in which the springs hold the mounting magnets in a retracted position, and a second position in which the mounting magnets contact the tank wall.

13. The ultrasonic transducer unit of claim 9, wherein the mounting magnets are rotatably threaded into the ultrasonic transducer and at least partially extend from the transducer, wherein rotation of the mounting magnets determines the position of the ultrasonic transducer relative to the tank wall when the ultrasonic transducer is mounted to the tank wall.

14. The ultrasonic transducer unit of claim 1, wherein upon mounting the ultrasonic transducer to the tank wall, the pressure at the interface between the acoustic coupler and the tank wall is about 1.5 pounds per square inch.

15. The ultrasonic transducer unit of claim 1, further comprising a temperature sensor.

16. The ultrasonic transducer unit of claim 1, wherein the acoustic coupler comprises silicone gel.

17. A system operable to measure a liquid level in a tank, the system comprising:

an ultrasonic transducer unit externally mountable to the tank, the ultrasonic transducer comprising;

an emitter to generate an ultrasonic beam to pass through a tank wall and to receive an echo of the ultrasonic beam off a surface of a liquid;

a transducer driver in electrical communication with the emitter;

an acoustic lens coupled to the emitter and configured to shape the ultrasonic beam and configured to diverge the ultrasonic beam and thereby provide a divergent ultrasonic beam after the ultrasonic beam passes through a tank wall;

an acoustic coupler disposed adjacent the acoustic lens and configured to increase transmission of the ultrasonic beam to the interface with the tank wall;

a communications unit in electrical communication with the ultrasonic transducer unit and operable to cause the transducer unit to generate the ultrasonic beam and to determine a time-of-flight measured between generating the ultrasonic beam and receiving the echo of the ultrasonic beam off the liquid surface;

a first interface operable to transmit the time-of-flight to a satellite data link; and

a second interface operable to transmit the time-of-flight to a portable electronic device.

18. The system of claim 17, wherein the second interface is a wireless interface.

19. The system of claim 17, wherein the second interface comprises a Bluetooth transceiver.

20. The system of claim 17, wherein the second interface is operable to receive a configuration instruction from the portable electronic device.

21. The system of claim 20, wherein the configuration instruction comprises a schedule for determining a time-of-flight and transmitting the time-of-flight using the satellite transmission unit.

22. The system of claim 20, wherein the configuration instruction comprises a dimension of the tank.

23. The system of claim 17, further comprising a satellite transmission unit connected to the first interface.

24. The system of claim 17, further comprising a battery in electrical communication with the emitter, transducer driver, the first interface, and the second interface to provide power thereto.

25. The system of claim 24, wherein the first interface is operable to transmit data corresponding to a power level of the battery.

26. The system of claim 25 further comprising a temperature sensor operable to determine a temperature of the liquid, and wherein the first interface is operable to transmit data corresponding to the temperature of the liquid.

27. A method of generating an ultrasonic beam to measure a liquid level in a tank, comprising:

providing an externally mounted ultrasonic transducer to generate an ultrasonic beam to pass through a tank wall and to receive an echo of the ultrasonic beam off a surface of a liquid;

configuring an acoustic lens to shape the ultrasonic beam and compensate for lensing effects of the ultrasonic beam passing through a tank wall;

configuring an acoustic coupler to increase transmission of the ultrasonic beam through the tank wall;

coupling the acoustic coupler to the acoustic lens;

coupling the acoustic lens to the emitter to receive the ultrasonic beam;

placing the emitter in electrical communication with a transducer driver; and

mounting the emitter, acoustic lens, and acoustic coupler to a tank wall such that the acoustic coupler and the acoustic lens are disposed between the emitter and the tank wall.

28. The method of claim 27, wherein the acoustic coupler is self-forming to the curvature of the tank.

29. The method of claim 27, further comprising disposing an acoustically transparent media between the acoustic coupler and the tank wall.

30. The method of claim 29, wherein the acoustically transparent media is silicone grease.

31. The method of claim 29, wherein the acoustically transparent media is silicone oil.

32. The method of claim 27, wherein the acoustic coupler comprises polyurethane.

33. The method of claim 32, wherein the hardness of the polyurethane is about 55 durometer, shore A.

34. The method of claim 32, wherein the hardness of the polyurethane is in the range of about 20 to about 80 durometer, shore A.

35. The method of claim 27, further comprising mounting the ultrasonic transducer to the tank wall using a plurality of mounting magnets connected to the ultrasonic transducer.

36. The method of claim 35, wherein the mounting magnets are adjustable such that the face of each mounting magnet is substantially parallel to the tank wall when the ultrasonic transducer is mounted to the tank.

37. The method of claim 35, further comprising connecting the mounting magnets to the ultrasonic transducer using springs.

38. The method of claim 37, further comprising:

initially providing the springs in a first position in which the springs hold the mounting magnets in a retracted position;

extending the springs to a second position in which the mounting magnets engage the tank wall.

39. The method of claim 35, wherein the mounting magnets are rotatably threaded into the ultrasonic transducer, and at least partially extend from the ultrasonic transducer, wherein rotation of the mounting magnets determines the position of the ultrasonic transducer relative to the tank wall.

40. The method of claim 27, wherein the pressure at the interface between the acoustic coupler and the tank wall is about 1.5 pounds per square inch.

41. A system operable to measure a liquid level in a tank, the system comprising:

an ultrasonic transducer unit externally mountable to the tank, the ultrasonic transducer comprising;

an emitter to generate an ultrasonic beam to pass through a tank wall and to receive an echo of the ultrasonic beam off a liquid surface;

a transducer driver in electrical communication with the emitter; and

an acoustic lens coupled to the emitter and configured to shape the ultrasonic beam and configured to diverge the ultrasonic beam and thereby provide a divergent ultrasonic beam after the ultrasonic beam passes through a tank wall;

a communications unit in electrical communication with the ultrasonic transducer unit and operable to cause the transducer unit to generate the ultrasonic beam and to determine a time-of-flight measured between generating the ultrasonic beam and receiving the echo of the ultrasonic beam off the liquid surface;

a first interface operable to transmit the time-of-flight by a satellite data link; and

a second interface operable to transmit the time-of-flight to a portable electronic device and to receive a configuration instruction from the portable electronic device.

42. The system of claim 41, further comprising an acoustic coupler disposed between the acoustic lens and the tank wall and configured to increase transmission of the ultrasonic beam to the interface with the tank wall.

43. The system of claim 41, wherein the second interface comprises a wireless data communications link.

44. The system of claim 41, wherein the second interface comprises a Bluetooth transceiver.

45. The system of claim 41, wherein the second interface is operable to transmit data about the liquid level in the tank.

46. The system of claim 41, wherein the second interface is operable to transmit data about the dimensions of the tank.

47. The system of claim 41, further comprising a battery in electrical communication with the emitter, transducer driver, the first interface, and the second interface to provide power thereto.

48. The system of claim 47, wherein the second interface is operable to transmit data corresponding to a power level of the battery.

49. The system of claim 48, further comprising a temperature sensor.

50. The system of claim 41, wherein the first interface is operable to transmit the time-of-flight by a satellite data link

51. A system for measuring a liquid level in a tank, comprising:

means for generating an ultrasonic beam;

means for controlling the divergence of the ultrasonic beam;

means for transmitting the ultrasonic beam through a tank wall;

means for receiving an echo of the ultrasonic beam off a liquid surface in the tank;

means for determining a time-of-flight between generating the ultrasonic beam and receiving the echo;

means for transmitting the time-of-flight to a satellite link;

means for transmitting the time-of-flight to a portable electronic device; and

means for calculating the liquid level using the time-of-flight.

52. The system of claim 51, wherein the means for transmitting the time-of-flight comprises a wireless data communications link.

53. The system of claim 51, wherein the means for transmitting the time-of-flight comprises a Bluetooth transceiver.

54. The system of claim 51, further comprising means for transmitting data about the dimensions of the tank to the portable electronic device.

55. The system of claim 51, further comprising means for providing power to the emitter, transducer driver, the first interface, and the second interface.

56. The system of claim 55, further comprising means for transmitting data about the power level of the means for providing power to the portable electronic device.