Ultrasonic sensor self test for integrity/performance verification
First Claim
1. A sensor comprising a wall having a surface for transmitting ultrasonic vibrations, a transducer coupled to the wall for transmitting a pulse forming an ultrasonic acoustic wave that propagates along the surface of the wall, a receiver for receiving a first signal indicating that the ultrasonic wave has been transmitted along the surface of the wall a first distance, and a receiver for receiving a second signal indicating the ultrasonic wave has been transmitted a second distance substantially less than the first distance to provide an indication that the transducer is acoustically coupled to the wall, wherein the first distance and the second distance extend parallel to the wall.
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Accused Products
Abstract
A contaminant sensor is provided which has an ultrasonic guided wave transducer that is bonded to a wall in which the ultrasonic energy is transmitted. A detector reflector is provided at a selected distance from the transducer, which will reflect signals that are affected or changed by contaminants collecting on an exposed surface of the wall. A self test reflector is positioned closely adjacent to the transducer and provides a reflected signal that is substantially unaffected by contaminants on the exposed surface of the wall, but which reflects signals only when the transducer assembly is functioning properly, and is properly bonded to the wall. The signal that is reflected by the self test reflector changes when the bond loosens. The receiver is activated right after transmission ceases to determine if the transmitter is operating.
28 Citations
27 Claims
- 1. A sensor comprising a wall having a surface for transmitting ultrasonic vibrations, a transducer coupled to the wall for transmitting a pulse forming an ultrasonic acoustic wave that propagates along the surface of the wall, a receiver for receiving a first signal indicating that the ultrasonic wave has been transmitted along the surface of the wall a first distance, and a receiver for receiving a second signal indicating the ultrasonic wave has been transmitted a second distance substantially less than the first distance to provide an indication that the transducer is acoustically coupled to the wall, wherein the first distance and the second distance extend parallel to the wall.
- 19. A sensor for detecting contaminants on a wall having opposite surfaces, a first of the surfaces being exposed to ambient conditions and on which contaminants can collect, a second of said surfaces having a first ultrasonic reflector thereon, a transducer assembly mounted on the second surface at a location spaced from the first ultrasonic reflector a first distance, the transducer assembly being capable of transmitting ultrasonic energy through the wall toward the first ultrasonic reflector, and being capable of receiving reflected signals from the first ultrasonic reflector to provide an output indicating receiving the reflected signals, and a second self test reflector positioned on the wall adjacent the transducer assembly to provide a signal indicating reflected ultrasonic energy transmitted by the transducer assembly that is substantially unaffected by contaminants on the surface of the wall exposed to ambient conditions, wherein the second self test reflector comprises a waveguide having a width extending lateral to a direction line extending between the transducer assembly and the first ultrasonic reflector that is substantially less than the width of the first ultrasonic reflector.
- 22. A method of testing an ultrasonic contaminant sensor for operability, the contaminant sensor comprising a transducer coupled to a wall having a surface so as to transmit ultrasonic waves along the wall, wherein the ultrasonic waves propagate along and parallel to the surface of the wall, the method comprising providing a first ultrasonic wave reflector on the wall at a first distance from the transducer, providing a second test ultrasonic wave reflector on the wall a second distance from the transducer which is substantially shorter than the first distance, wherein the first distance and the second distance extend along the wall, transmitting an ultrasonic wave signal from the transducer and receiving ultrasonic wave signals at a time subsequent to transmitting to determine whether the ultrasonic waves are reflected from the second test reflector.
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27. A method for testing an ultrasonic contaminant sensor for operability, the method comprising:
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providing a wall having opposite surfaces, a first of the surfaces being exposed to ambient conditions and on which contaminants can collect;
providing a transducer assembly mounted on the second surface at a location spaced from the first ultrasonic reflector a first distance;
providing a first ultrasonic reflector having a width mounted on a second of said surfaces and a second self test reflector positioned on the wall adjacent the transducer assembly, wherein the second self test reflector comprises a waveguide having a width, the width of the first ultrasonic reflector and the width of the wave guide lateral to a direction line extending between the transducer assembly and the first ultrasonic reflector, wherein the width of the waveguide is substantially less than the width of the first ultrasonic reflector;
transmitting an ultrasonic wave signal from the transducer assembly; and
,receiving ultrasonic wave signals at a time subsequent to transmitting to determine whether the ultrasonic waves are reflected from the second self test reflector.
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Specification