Ultrasonic method for material monitoring

• US 5,987,994 A
• Filed: 03/26/1998
• Issued: 11/23/1999
• Est. Priority Date: 05/24/1996
• Status: Expired due to Fees

• Current Assignee: Drexelbrook Engineering Co. (Ametek Incorporated)
• Original Assignee: Drexelbrook Engineering Co. (Ametek Incorporated)
• Inventors: Mitchell, Glen, Kramer, L. Jonathan, Maltby, Frederick L.
• Primary Examiner(s): Brock, Michael
• Assistant Examiner(s): Kwok, Helen C.
• Application Number:
  US09/048,606
• Time in Patent Office: 607 Days
• Field of Search: 73/597, 73/612, 73/618, 73/290 V, 73/602, 73/646, 340/612, 340/618, 340/621, 364/506, 364/508, 364/562
• US Class Current: 73/646
• CPC Class Codes: G01F 23/2962 Measuring transit time of reflected waves
• CPC Class Codes: G01N 2291/02836 Flow rate, liquid level

Abstract

An ultrasonic measurement method in an ultrasonic measurement system having an ultrasonic transducer includes emitting an ultrasonic pulse from the ultrasonic transducer. An ultrasonic pulse is received in accordance with a pulse travel time wherein the amplitude of the received ultrasonic pulse varies according to the pulse travel time. A first electrical signal is provided representative of the received ultrasonic pulse wherein the amplitude of the first electrical signal varies in accordance with the pulse travel time. A second electrical signal is provided in accordance with the first electrical signal wherein the amplitude of the second electrical signal is substantially independent of the pulse travel time. In order to determine the second electrical signal variable amplification is applied to the first electrical signal in accordance with the travel time. A distance is determined according to the pulse travel time wherein the distance is representative of the distance between the transducer and a material surface.

Claims

1. An ultrasonic measurement method for use in an ultrasonic measurement system having an ultrasonic transducer, comprising the steps of:

(a) emitting an ultrasonic pulse from an ultrasonic transducer;

(b) receiving an ultrasonic pulse in accordance with a pulse travel time, wherein the amplitude of said received ultrasonic pulse varies according to said pulse travel time;

(c) providing a first electrical signal representative of said received ultrasonic pulse;

(d) applying variable amplification to said first electrical signal in accordance with said pulse travel time; and

(e) providing a second electrical signal in accordance with said first electrical signal, wherein the amplitude of said second electrical signal is substantially independent of said pulse travel time during a time period corresponding to a range of said pulse travel time.

2. The ultrasonic measurement method of claim 1 comprising the step of determining said pulse travel time in accordance with a measurement of the duration of a time interval.

3. The ultrasonic measurement method of claim 2, comprising the step of measuring said duration of said time interval by measuring the time elapsed between said emitting and said receiving.

4. The ultrasonic measurement method of claim 3, comprising the step of determining a distance D in accordance with said pulse travel time.

5. The ultrasonic measurement method of claim 4, wherein the step of determining said distance D comprises determining said distance D in accordance with the relationship D=RT/2, wherein R is the speed of sound and T is said elapsed time.

6. The ultrasonic measurement method of claim 5, wherein said distance D is representative of the distance between said transducer and a material surface.

7. The ultrasonic measurement method of claim 6, comprising the step of determining a further distance in accordance with said determined distance D.

8. The ultrasonic measurement method of claim 7, wherein said further distance comprises the distance between a vessel bottom and said material surface.

9. The ultrasonic measurement method of claim 1, comprising the step of providing a gain control signal in accordance with said pulse travel time.

10. The ultrasonic measurement method of claim 9, comprising the step of applying said gain control signal to a variable amplifier.

11. The ultrasonic measurement method of claim 9, wherein said ultrasonic measurement system includes at least one integration device comprising the step of determining said gain control signal by integrating during said pulse travel time using said integration device.

12. The ultrasonic measurement method of claim 11, comprising the step of selectively applying constants to said integration device to provide measurement sensitivity substantially independent of said pulse travel time.

13. The ultrasonic measurement method of claim 9, comprising the step of providing a processor for providing said gain control signal.

14. The ultrasonic measurement method of claim 13, comprising the step of performing calculations by said processor to provide said gain control signal.

15. The ultrasonic measurement method of claim 13, comprising the step of performing table look ups by said processor to provide said gain control signal.

16. The ultrasonic measurement method of claim 1, comprising the step of applying a drive pulse to an ultrasonic transducer having an ultrasonic crystal for emitting said ultrasonic pulse.

18. The ultrasonic measurement method of claim 1, wherein said received ultrasonic pulse is formed by reflecting said emitted ultrasonic pulse off an object.

19. The ultrasonic measurement method of claim 18, wherein said object comprises a material surface.

21. The ultrasonic measurement method of claim 1, wherein said second electrical signal is applied to an analog-to-digital converter.

22. The ultrasonic measurement method of claim 1, wherein said emitted ultrasonic pulse is attenuated to provide said received ultrasonic pulse and step (d) compensates for said attenuating.

23. The ultrasonic measurement method of claim 1, wherein said method includes providing a plurality of ultrasonic transducers each transducer of said plurality of transducers emitting an ultrasonic pulse to provide a plurality of ultrasonic pulses.

24. The ultrasonic measurement method of claim 23, comprising the step of determining a plurality of distance measurements in accordance with said plurality of ultrasonic pulses.

25. The ultrasonic measurement method of claim 24, comprising the step of controlling a traveling gate in accordance with said plurality of distance measurements.

26. The ultrasonic measurement method of claim 24, comprising the step of determining a plurality of levels of a material surface in accordance with said plurality of distance measurements.

27. The ultrasonic measurement method of claim 1, comprising the step of emitting a plurality of ultrasonic pulses and determining the relationship between said pulse travel time and said amplitude of said first electrical signal for each pulse of said plurality of pulses.

28. The ultrasonic measurement method of claim 27, comprising the step of approximating said relationship to provide a plurality of correction parameters.

29. The ultrasonic measurement method of claim 28, wherein step (d) comprises the step of applying said correction parameters to said first electrical signal.

17. An ultrasonic measurement method, comprising the steps of:

(a) emitting an ultrasonic pulse from an ultrasonic transducer;

(b) receiving an ultrasonic pulse in accordance with a pulse travel time, wherein the amplitude of said received ultrasonic pulse varies according to said pulse travel time;

(c) providing a first electrical signal representative of said received ultrasonic pulse;

(d) providing a gain control signal in accordance with said pulse travel time;

(e) applying said gain control signal to a variable amplifier that amplifies the first electrical signal;

(f) providing a second electrical signal in accordance with said first electrical signal, wherein the amplitude of said second electrical signal is substantially independent of said pulse travel time during a time period corresponding to a range of the pulse travel time; and

(g) applying the output of said variable amplifier to a four to twenty amp indicator device.

20. An ultrasonic measurement method, comprising the steps of:

(a) emitting an ultrasonic pulse from an ultrasonic transducer;

(b) receiving an ultrasonic pulse in accordance with a pulse travel time, wherein the amplitude of said received ultrasonic pulse varies according to said pulse travel time;

(c) providing a first electrical signal representative of said received ultrasonic pulse;

(d) providing a gain control signal in accordance with said pulse travel time;

(e) applying said gain control signal to cascaded variable amplifiers that amplify the first electrical signal; and

(f) providing a second electrical signal in accordance with said first electrical signal, wherein the amplitude of said second electrical signal is substantially independent of said pulse travel time during a time period corresponding to a range of the pulse travel time.

30. An ultrasonic measurement method, comprising the steps of:

(a) emitting an ultrasonic pulse from an ultrasonic transducer;

(b) receiving an ultrasonic pulse in accordance with a pulse travel time, wherein the amplitude of said received pulse varies according to said pulse travel time;

(c) providing a first electrical signal representative of said received ultrasonic pulse;

(d) applying relatively lower amplification to said first electrical signal for relatively lower values of the pulse travel time and applying relatively larger amplification to said first electrical signal for relatively higher values of the pulse travel time; and

(e) providing a second electrical signal in accordance with said first electrical signal, wherein the amplitude of the second electrical signal is substantially independent of said pulse travel time during a time period corresponding to a range of the pulse travel time.

31. An ultrasonic measurement method, comprising the steps of:

(a) emitting an ultrasonic pulse from an ultrasonic transducer;

(b) receiving an ultrasonic pulse in accordance with a pulse travel time, wherein the amplitude of said received ultrasonic pulse varies according to said pulse travel time;

(c) providing a first electrical signal representative of said received ultrasonic pulse;

(d) providing a gain control signal for amplification of the first electrical signal in accordance with said pulse travel time, wherein said gain control signal is determined by performing first and second integrations during said pulse travel time to provide first and second integration signals; and

(e) providing a second electrical signal in accordance with said first electrical signal, wherein the amplitude of said second electrical signal is substantially independent of said pulse travel time during a time period corresponding to a range of the pulse travel time.

32. The ultrasonic measurement method of claim 31, wherein said first integration signal is proportional to said pulse travel time and said second integration signal is proportional to said pulse travel time squared.

33. The ultrasonic measurement method of claim 31, comprising the step of summing said first and second integration signals to form said gain control signal.

34. An ultrasonic measurement method, comprising the steps of:

(a) emitting an ultrasonic pulse from an ultrasonic transducer;

(b) receiving an ultrasonic pulse in accordance with a pulse travel time, wherein the amplitude of said received ultrasonic pulse varies according to said pulse travel time;

(c) providing a first electrical signal representative of said received ultrasonic pulse;

(d) providing a second electrical signal in accordance with said first electrical signal, wherein the amplitude of said second electrical signal is substantially independent of said pulse travel time during a time period corresponding to a range of the pulse travel time;

wherein a level of a material is controlled in accordance with said second electrical signal.

35. An ultrasonic measurement method, comprising the steps of:

(a) emitting an ultrasonic pulse from an ultrasonic transducer;

(b) receiving an ultrasonic pulse in accordance with a pulse travel time, wherein the amplitude of said received ultrasonic pulse varies according to said pulse travel time, and the emitted ultrasonic pulse is attenuated to provide said received electronic pulse;

(c) providing a first electrical signal representative of said received ultrasonic pulse; and

(d) providing a second electrical signal in accordance with said first electrical signal, wherein the amplitude of said second electrical signal is substantially independent of said pulse travel time during a time period corresponding to a range of the pulse travel time;

wherein step (d) compensates for said attenuating and said compensating includes compensating for humidity.

36. An ultrasonic measurement, comprising the steps of:

(a) emitting an ultrasonic pulse from an ultrasonic transducer;

(b) receiving an ultrasonic pulse in accordance with a pulse travel time, wherein the amplitude of said received ultrasonic pulse varies according to said pulse travel time;

(c) providing a first electrical signal representative of said received ultrasonic pulse;

(d) providing a second electrical signal in accordance with said first electrical signal, wherein the amplitude of said second electrical signal is substantially independent of said pulse travel time during a time period corresponding to a range of said pulse travel time; and

(e) applying said second electrical signal to a two-wire measurement system.

37. An ultrasonic measurement method, comprising the steps of:

(a) emitting an ultrasonic pulse from an ultrasonic transducer;

(b) receiving an ultrasonic pulse in accordance with a pulse travel time, wherein the amplitude of said received ultrasonic pulse varies according to said pulse travel time;

(c) providing a first electrical signal representative of said received ultrasonic pulse and applying variable amplification to said first electrical signal in accordance with said pulse travel time;

(d) providing a second electrical signal in accordance with said first electrical signal, wherein the amplitude of said second electrical signal is substantially independent of said pulse travel time during a time period corresponding to a range of the pulse travel time; and

(e) determining the level of a material in accordance with said second electrical signal.

38. An ultrasonic measurement system, comprising:

(a) means for emitting an ultrasonic pulse from an ultrasonic transducer;

(b) means for receiving an ultrasonic pulse in accordance with a pulse travel time, wherein the amplitude of said received ultrasonic pulse varies according to said pulse travel time;

(c) means for providing a first electrical signal representative of said received ultrasonic pulse and applying variable amplification to said first electrical signal in accordance with said pulse travel time;

(d) means for providing a second electrical signal in accordance with said first electrical signal, wherein the amplitude of said second electrical signal is substantially independent of said pulse travel time during a time period corresponding to a range of the pulse travel time; and

(e) means for determining the level of a material in accordance with said second electrical signal.

39. An ultrasonic measurement system, comprising:

(a) an ultrasonic transducer that emits an ultrasonic pulse;

(b) a receiver that receives an ultrasonic pulse in accordance with a pulse travel time, wherein the amplitude of said received ultrasonic pulse varies according to said pulse travel time;

(c) signal processing circuitry, coupled to the receiver, that provides a first electrical signal representative of said received ultrasonic pulse and a second electrical signal in accordance with said first electrical signal, wherein the amplitude of said second electrical signal is substantially independent of said pulse travel time during a time period corresponding to a range of the pulse travel time; and

(d) a microprocessor that determines the level of a material in accordance with said second electrical signal.

40. The system of claim 39, wherein the receiver is integral with the ultrasonic transducer.

41. An ultrasonic measurement system having an ultrasonic transducer, comprising:

(a) means for emitting an ultrasonic pulse from said ultrasonic transducer;

(b) means for receiving an ultrasonic pulse in accordance with a pulse travel time, wherein the amplitude of said received ultrasonic pulse varies according to said pulse travel time;

(c) signal processing circuitry that provides a first electrical signal representative of said received ultrasonic pulse, applies variable amplification to said first electrical signal in accordance with said pulse travel time, and provides a second electrical signal in accordance with said first electrical signal, wherein the amplitude of said second electrical signal is substantially independent of said pulse travel time during a time period corresponding to a range of said pulse travel time.

42. The system of claim 41, wherein the receiver is integral with the ultrasonic transducer.