Acoustic inspection device

• US 20040035208A1
• Filed: 08/21/2002
• Published: 02/26/2004
• Est. Priority Date: 08/21/2002
• Status: Active Grant

• Current Assignee: Aaron A. Diaz, Brion J. Burghard, Chester L. Shepard, James R. Skorpik, Joe C. Harris, Jonathan T. Smalley, Juan D. Valencia, Larry D. Reid, Mullen O. Dennis, Richard A. Pappas, Theodore T. Taylor, Todd J. Samuel
• Original Assignee: Aaron A. Diaz, Brion J. Burghard, Chester L. Shepard, James R. Skorpik, Joe C. Harris, Jonathan T. Smalley, Juan D. Valencia, Larry D. Reid, Mullen O. Dennis, Richard A. Pappas, Theodore T. Taylor, Todd J. Samuel
• Inventors: Skorpik, James R., Burghard, Brion J., Pappas, Richard A., Samuel, Todd J., Valencia, Juan D., Diaz, Aaron A., Harris, Joe C., Reid, Larry D., Shepard, Chester L., Smalley, Jonathan T., Mullen, O. Dennis, Taylor, Theodore T.
• Granted Patent: US 6,938,488 B2
• Time in Patent Office: Days
• US Class Current: 73/597
• CPC Class Codes: G01N 2291/02881 Temperature
• CPC Class Codes: G01N 2291/044 Internal reflections (echoes), e.g. on walls or defects
• CPC Class Codes: G01N 29/024 by measuring propagation velocity or propagation time of acoustic waves
• CPC Class Codes: G01N 29/0609 Display arrangements, e.g. colour displays indicating or recording in connection with measuring in general G01D
• CPC Class Codes: G01N 29/07 by measuring propagation velocity or propagation time of acoustic waves
• CPC Class Codes: G01N 29/222 Constructional or flow details for analysing fluids optoacoustic fluid cells G01N29/2425
• CPC Class Codes: G01N 29/223 Supports, positioning or alignment in fixed situation mounting transducers per se G10K11/004
• CPC Class Codes: G01N 29/326 compensating for temperature variations
• CPC Class Codes: G01N 29/348 with frequency characteristics, e.g. single frequency signals, chirp signals measuring frequency of mechanical vibrations or acoustic waves in general G01H1/06, G01H3/04; measuring frequency or analysing frequency spectra G01R23/00

Abstract

An ultrasound inspection apparatus particularly adapted to examine containers (sealed or unsealed) containing a liquid or solid bulk material. The apparatus has an overall configuration of a hand held pistol with a front transducer contact surface that is positioned against a front wall of the container. An ultrasound pulse is transmitted from the apparatus to be reflected from a back wall of a container being investigated. The received echo pulse is converted to a digital waveform. The waveform is analyzed relative to temperature, travel distance of the pulse(s), and time of travel to ascertain characteristics of the liquid or other materials and to provide identification of the same.

Claims

1. A portably operable ultrasound inspection apparatus particularly adapted to inspect a container which has a containing chamber to contain a quantity of material therein, and which has a front wall and a back wall defining at least in part said containing chamber, said inspection apparatus comprising:

a) a housing section;

b) a sensing section which is mounted to said housing section and which is arranged to transmit transmitted ultrasound pulse(s) and receive reflected ultrasound pulse(s) and to provide an analog signal(s) representative of a reflected waveform(s) of the reflected ultrasonic pulse(s);

c) said sensing section comprising a transducer assembly with a transducer placement location, and at least a first higher frequency transducer and a second lower frequency transducer which are arranged to be better able to transmit pulse(s) in a higher frequency range and in a lower frequency range, respectively, said sensing section being arranged so that either of said transducers can be mounted in said placement location to transmit ultrasound pulses;

d) a circuit section arranged to generate electric pulse(s) for said sensing section, receive the analog signal(s) from said sensing section, and to convert said analog signal(s) to digital signal(s) representative of the reflected waveform(s) of the reflected ultrasonic pulse(s);

e) a temperature sensor to ascertain temperature of the quantity of material in the chamber of the container and provide a temperature output;

f) a computer arranged to receive said digital signal(s) and said temperature output, and to correlate these with travel distance and time of travel of the transmitted pulse(s) and reflected pulse(s) so that with the transmitted pulse(s) and reflected pulse(s) traveling in the chamber of the container, information of velocity of the pulse(s) can be developed and related to identification and/or location of material and/or object(s) in the container.

2. The apparatus as recited in claim 1, wherein said housing comprises a horizontally extending upper housing portion having a front end and a rear end, said sensing section being located at a forward portion of said upper housing portion and said circuit section being located at a rear portion of the upper housing section, said housing further comprising a hand grip portion having an upper end connecting to said upper housing section and a lower end, said apparatus further comprising a trigger section mounted to the hand grip portion so as to be operable by the person manually grasping the hand grip portion.

3. The apparatus as recited in claim 2, wherein the upper end of the hand grip portion is located forwardly of the rear end of the upper housing and rearwardly of the front end of the upper housing, said hand grip portion having a lengthwise alignment axis which extends downwardly from said upper housing portion at a moderate downward and rearward slant from a forward to rear lengthwise alignment axis of said upper housing section.

4. The apparatus as recited in claim 2, wherein said upper horizontally extending housing portion has an upper surface portion thereof configured as a mounting platform on which said computer can be positioned with an upper graphic interface of said computer being readily observable by an operator who is grasping the hand grip portion of the housing.

5. The apparatus as recited in claim 4, wherein said mounting platform to support a computer is positioned on an upper rear surface portion of said upper housing section.

6. The apparatus as recited in claim 2, wherein there is a power supply section for said apparatus, said power supply section being connected to a lower end portion of said hand grip portion of the housing.

7. The apparatus as recited in claim 6, wherein the power supply section is battery powered and said power supply section is removably mounted to said handle grip portion.

8. The apparatus as recited in claim 2, wherein said temperature sensor is located at a forward end portion of the sensing section and is in close proximity to the transducer that is located in the placement location, so that with the transducer being positioned with a contact surface thereof in contact with a container to be inspected, said temperature sensor is also adjacent to a container being inspected.

9. The apparatus as recited in claim 2, wherein each of said transducers is part of a related transducer unit, with each transducer unit comprising a holding case in which the related transducer is positioned and an electrically-connecting portion enabling the transducer to have an operative connection with the circuit section with the transducer being in the placement position.

10. The apparatus as recited in claim 9, wherein each of the transducer units for the first and second transducers is removably mounted in the placement location so that each transducer as part of its related unit is removed from and replaced in the sensing section as a transducer unit.

11. The apparatus as recited in claim 9, wherein said sensing section comprises a transducer unit engaging portion adapted to engage a rear portion of the transducer unit which is in the placement location, said engaging portion having a compression spring which yieldingly engages the transducer unit to urge it to a forward engaging position.

12. The apparatus as recited in claim 11, wherein each of the transducer units for the first and second transducers is removably mounted in the placement location so each transducer as part of each related unit is removed from and replaced in the sensing section as the transducer unit.

13. The apparatus as recited in claim 10, wherein there are at least two temperature sensors, with each of the two temperature sensors being a component of a related one of the transducer units and positioned so as to be located at a forward front contact face of its related transducer so as to be able to be in close proximity with a container being inspected by said inspection apparatus.

14. The inspection apparatus as recited in claim 1, wherein each of said transducers comprises a front contact surface which is arranged to be positioned adjacent to a surface of a container being inspected, and a front contact layer of a synthetic rubber and/or rubber material which covers said front contact surface, said synthetic rubber and/or rubber material being moderately yielding so as to be able to conform to the surface of the container being inspected.

15. The inspection apparatus as recited in claim 14, wherein said front contact layer has an acoustic impedance no greater than 4 gm cm⁻

2 sec<sup>−

1</sup>×

10⁵, and a longitudinal acoustic velocity between about 0.05 to 0.075 inches per microsecond and a density between about 0.9 to 3.0 gm cm<sup>−

3</sup>.

16. The apparatus as recited in claim 15, wherein said acoustic impedance is no greater than 2.5 gm cm⁻

2 sec¹×

10⁵, and said longitudal acoustic velocity is between about 0.06 to 0.065 inches per microsecond and a density is between about 1.2 to 1.5 gm cm<sup>−

3</sup>.

17. The apparatus as recited in claim 14, wherein said front contact layer is made of a material which comprises at least one of solid water, butyl rubber, polyurethane, urethane, RTV, silicone rubber, Ecothane®

, Pellathane®

, and combinations thereof.

18. The inspection apparatus as recited in claim 15, wherein said material for said front contact layer comprises neoprene.

19. The inspection apparatus as recited in claim 14, wherein said front contact layer as an acoustic impedance which is no greater than 4 gm cm⁻

2 sec<sup>−

1</sup>×

10⁵, and longitudal acoustic velocity which is between about 0.05 to 0.075 inches per microsecond and a density which is between about 0.9 to 3.0 gm cm<sup>−

3</sup> and said front contact layer is made of a material which comprises at least one of solid water, butyl rubber, polyurethane, urethane, RTV, silicone rubber, Ecothane®

, Pellathane®

, and combinations thereof.

20. The inspection apparatus as recited in claim 14, wherein said front contact layer is bonded to the contact surface of its related transducer by means of a liquid adhesive which is applied between the contact surface of the related transducer and the front contact layer, with the front contact layer being pressed against the adhesive layer and the adhesive layer, and the front contact layer are exposed to a low pressure gaseous environment to cause degassing of the adhesive layer.

21. The inspection apparatus as recited in claim 19, wherein said liquid adhesive comprises at least in part urethane.

22. The inspection apparatus as recited in claim 1, wherein said circuit section comprises a pulser section which has a high frequency pulser circuit portion and a low frequency pulser circuit portion, with these high and low frequency pulser circuit portions being arranged to respond to a high frequency trigger signal or a lower trigger frequency signal to generate, respectively, a high frequency pulse or a low frequency pulse depending upon whether the high frequency transducer or the low frequency transducer is in the transducer placement location.

23. The inspection apparatus as recited in claim 17, wherein said high frequency pulser circuit portion is arranged to receive the high frequency trigger signal, which is directed to a driver circuit that sends a gate signal to a high voltage switch which outputs a high voltage pulse which is in turn directed to the high frequency transducer.

24. The inspection apparatus as recited in claim 22, wherein said high frequency pulse is a square wave pulse.

25. The inspection apparatus as recited in claim 22, wherein said low frequency pulse comprises a sinusoidal burst of a plurality of cycles.

26. The inspection apparatus as recited in claim 1, wherein said circuit section comprises a receiver circuit section which is arranged to receive the analog signal(s) from the sensing section, said receiver circuit section comprising a variable gain amplifier responsive to an input to modify amplitude of the received signal(s).

27. The inspection apparatus as recited in claim 26, wherein said receiver circuit section also comprises a voltage limiter to limit voltage of the received signal(s) to an acceptable level and a high-pass filter to pass only higher frequency portions of the received pulse(s).

28. The inspection apparatus as recited in claim 26, wherein the variable gain amplifier is under the control of the circuit section and also is under control of a user of the inspection apparatus by inputs entered through the computer section.

29. The inspection apparatus as recited in claim 1, wherein said circuit section comprises a signal processing and control section which is arranged to receive the analog signal(s), convert the analog signal(s) to digital signal(s) and to select an adequately large number of samples from the digital signal(s) representing a received waveform(s) of a reflected ultrasound pulse(s), which are then transmitted to the computer.

30. The inspection apparatus as recited in claim 29, wherein said signal processing and control section also functions to send enabling signals to a pulser section of the circuit section to initiate the low frequency and the high frequency pulse(s).

31. The inspection apparatus as recited in claim 1, wherein there is a signal processing and control section which functions to control at least one delay time, digitizing rate, frequency, pulse width, and combinations thereof, of electric pulses being transmitted to the transducers.

32. The inspection apparatus as recited in claim 31, wherein said signal processing and control section further comprises a microprocessor having operative connections to the computer section, and controlling delay time, digitizing rate, frequency of burst, or width of electric pulses and combinations thereof through instructions from the computer, which instructions are capable of being entered by an operator.

33. The inspection apparatus as recited in claim 32, wherein a signal processing and control section further comprises a gate array component having an operative connection with a waveform and analog-to-digital converter of the signal processing and control section to effect the control functions as recited in claim 32.

34. The inspection apparatus as recited in claim 1, wherein there is a signal processing and control section comprising circuitry to receive an analog temperature output from a temperature sensor, said temperature sensor being arranged to sense temperature of material in a container being inspected, and to convert the analog or digital temperature signal.

35. The inspection apparatus as recited in claim 34, wherein the signal processing and control section is responsive to interrogation from an operator utilizing the computer to ascertain from the signal processing and control section temperature readings, and also said computer is arranged to periodically request and receive input temperature readings from the signal processing and control section to the computer.

36. The inspection apparatus as recited in claim 1, wherein said circuit section comprise a RAM component which has an operative connection to the computer section and also to a microcontroller of the signal processing and control section so as to be accessible to an operator utilizing the computer section to enable the operator to operate the microcontroller to obtain information for diagnostic purposes or other purposes.

37. The inspection apparatus as recited in claim 1, wherein there is a display section to provide visual indicator(s) of activation, error and/or power in operation of the inspection apparatus.

38. The inspection apparatus as recited in claim 1, wherein said circuit section further comprises a storage component to retain information when power is shut off so that when an operator starts operation of the inspection apparatus, the same operating parameters of the apparatus will be extant as at the time the inspection apparatus was shut down.

39. The inspection apparatus as recited in claim 38, wherein said storage component comprises an EPROM chip component.

40. The inspection apparatus as recited in claim 1, wherein said circuit section is arranged to receive the analog signal(s) and convert them to digital signals, and said computer is arranged to compute average amplitude of the digital signal and from this establish a base line of the waveform(s) from which to make further computations.

41. The inspection apparatus as recited in claim 40, wherein said apparatus is arranged to select an adequately large number of samples from a signal representing a received waveform and representing a reflected ultrasound pulse, which are then transmitted to the computer, said computer being arranged to identify an amplitude level below which are the amplitudes of a preselected percentage of the samples and to utilize said amplitude of a predetermined percentage of the samples as a noise level amplitude for further calculations.

42. The inspection apparatus as recited in claim 41, wherein said computer is arranged to select a threshold level of signal amplitude which is a predetermined amplitude greater than the noise level amplitude and by which peaks of the waveforms are identified.

43. The inspection apparatus as recited in claim 42, wherein said computer is arranged to select peaks in the waveform(s) to ascertain time intervals in paths of travel between waveform peak portions above the threshold level and initially seeking to identify a time interval between a first back wall echo and a second back wall echo represented in the waveform(s).

44. The inspection apparatus as recited in claim 43, wherein if there is an occurrence where a second back wall echo is not able to be identified, said computer is arranged to then ascertain location of a leading edge portion of the first back wall echo in the waveform(s) for ascertaining a time interval between a forward ring down portion of the waveform and the leading edge portion of the first back wall echo of the waveform.

45. The inspection apparatus as recited in claim 42, wherein said computer is arranged to ascertain amplitude of peak portion of the waveform(s) and ascertaining an early arriving peak waveform portion(s) of lesser amplitude than a later arriving waveform(s) as a manner of identifying a false echo or echoes in the waveform(s) representing presence of a reflection interface other than a back wall interface.

46. The inspection apparatus as recited in claim 43, wherein said computer is arranged to utilize a correlation technique to correlate said first and second back wall echoes as a means of ascertaining a time interval between the first and second back wall echoes.

47. The inspection apparatus as recited in claim 1, wherein said computer is arranged to establish a threshold level of received waveform(s) to identify a time interval(s) between waveform peaks and also a temperature input from the temperature sensor and a travel time input, correlating said time interval(s) and travel distance input to establish a temperature adjusted velocity of ultrasonic pulses.

48. The inspection apparatus as recited in claim 47, wherein said computer has a database of materials and related temperature adjusted ultrasound velocities through the materials, and said computer is arranged to correlate said temperature adjusted velocity of the ultrasonic pulse(s) to identify the material through which the ultrasonic pulse(s) has traveled.

49. The inspection apparatus as recited in claim 48, wherein said computer comprises a user input interface by which at least one of amplitude, burst frequency, pulse width, digitizing rate, and combinations thereof are able to be controlled by the user.

50. The inspection apparatus as recited in claim 49, wherein said computer comprises a graphic display by which the waveform(s) is visibly displayed to the user.

51. The inspection apparatus as recited in claim 50, wherein said computer also has capability of displaying parameters of the received waveform comprising at least one of threshold level(s), noise level(s), waveform portion locations relative to waveform analysis and/or examination, and combinations thereof.

52. The inspection apparatus as recited in claim 47, wherein said computer comprises a graphic display by which the waveform(s) is visibly displayed to the user.

53. The inspection apparatus as recited in claim 52, wherein said computer also has capability of displaying parameters of the received waveform comprising at least one of threshold level(s), noise level(s), waveform portion locations relative to waveform analysis and/or examination, and combinations thereof.

54. The inspection apparatus as recited in claim 1, wherein said computer comprises a user input interface by which at least one of amplitude, first frequency, pulse width, digitizing rate, and combinations thereof are able to be controlled by the user.

55. An ultrasound inspection apparatus particularly adapted to inspect a container in a process line, wherein said container has a containing chamber to contain a quantity of material therein, and which has a front wall and a back wall defining at least in part said containing chamber, said inspection apparatus comprising:

a) a housing section;

b) a sensing section which is mounted to said housing section and which is arranged to transmit transmitted ultrasound pulse(s) and receive reflected ultrasound pulse(s) and to provide an analog signal(s) representative of a reflected waveform(s) of the reflected ultrasonic pulse(s);

c) a sensing section comprising a transducer assembly with a transducer placement location, and at least a first higher frequency transducer and a second lower frequency transducer which are arranged to be better able to transmit pulse(s) in a higher frequency range and in a lower frequency range, respectively, said sensing section being arranged so that either of said transducers can be mounted in said placement location to transmit ultrasound pulses;

d) a circuit section arranged to generate electric pulse(s) for said sensing section, receive the analog signal(s) from said sensing section, and to convert said analog signal(s) to digital signal(s) representative of the reflected waveform(s) of the reflected ultrasonic pulse(s);

e) a temperature sensor to ascertain temperature of the quantity of material in the chamber of the container and provide a temperature output;

f) a computer arranged to receive said digital signal(s) and said temperature output, and to correlate these with travel distance and time of travel of the transmitted pulse(s) and reflected pulse(s) so that with the transmitted pulse(s) and reflected pulse(s) traveling in the chamber of the container, information of velocity of the pulse(s) is able to be developed and related to identification and/or location of material and/or object(s) in the container.

56. A method of inspecting a container which has a containing chamber to contain a quantity of material therein, and which has a front wall and a back wall defining at least in part said containing chamber, said method comprising:

a) providing an ultrasound inspection apparatus comprising;

i) a housing section;

ii) a sensing section which is mounted to said housing section and which comprises at least one transducer;

iii) a circuit section;

iv) a temperature sensor; and

v) a computer.

b) selecting a front wall transmitting location at which an ultrasound pulse is to be transmitted to a back wall receiving location;

c) ascertaining a travel distance from the front wall location to the back wall receiving location and entering information relating to said travel distance into said computer;

d) positioning the inspection apparatus so that a front contact portion of the transducer is positioned at the transmitting location on the container and transmitting an ultrasound pulse into the container toward the back wall receiving location and receiving a reflected echo pulse from the back wall;

e) developing an analog signal from the received echo pulse and transmitting said analog signal to the circuit section to convert the analog signal to a digital waveform which is in turn transmitted to the computer;

f) utilizing said temperature sensor to ascertain temperature of the material in the container and to transfer information related to said temperature to the computer; and

g) causing said computer to correlate travel distance of the ultrasound pulse(s), the time of travel of said pulse(s) and temperature of the contained material, develop a temperature corrected velocity value of the ultrasound pulse(s), and correlate this to information relating to various materials which could be in the container to then develop information as to the contents of the container and/or ascertain presence of an object in the container.