Abstract: A spark detector indicates the presence of a spark by analyzing sound waves generated when an electrical spark is produced from an electrical spark generator located on an igniter rod. The spark detector includes an acoustic sensor that is in communication with the igniter rod to determine the time for the spark sound wave to travel through the igniter rod to the acoustic sensor. If a spark is not detected, the spark detector may output a signal indicating at least one of (i) the spark was not detected, (ii) to replace the electrical spark generator immediately, or (iii) replace the electrical spark generator soon such as at the next scheduled maintenance. Furthermore, the spark detector may be calibrated based on current temperature of the igniter rod based upon time of propagation of a pulse sound wave, generated by a pulse-echo generator, to reflect off an end of the igniter rod.

Abstract: The present disclosure provides a leak sensor assembly which is configured to detect the leakage of gas from a component of a piping system. The leak sensor assembly includes a housing and at least one sensor. The housing is configured to be positioned proximate to the component and forms a pocket which allows gas leaked from the component to concentrate within the pocket in a generally uniform dispersion. The at lease one sensor is configured to detect the presence and concentration of gas within the pocket of the housing.

Abstract: A spark detector indicates the presence of a spark by analyzing sound waves generated when an electrical spark is produced from an electrical spark generator located on an igniter rod. The spark detector includes an acoustic sensor that is in communication with the igniter rod to determine the time for the spark sound wave to travel through the igniter rod to the acoustic sensor. If a spark is not detected, the spark detector may output a signal indicating at least one of (i) the spark was not detected, (ii) to replace the electrical spark generator immediately, or (iii) replace the electrical spark generator soon such as at the next scheduled maintenance. Furthermore, the spark detector may be calibrated based on current temperature of the igniter rod based upon time of propagation of a pulse sound wave, generated by a pulse-echo generator, to reflect off an end of the igniter rod.

Abstract: The current invention relates to a conductivity-dielectric (CD) electrode design with apertures that allow compressional waves to propagate away from the surface of the acoustic wave device unimpeded. This prevents reflection of compressional waves that would interact with the viscosity sensor surface, thus altering the device response. It allows compressional waves to pass through, and allows the dual mode viscosity sensor responses to be utilized for density/viscosity/elasticity measurement and correlation. The invention further offers methods of instrumentation to detect unwanted reflections, to compensate, and to correct for the distortions caused by reflections. Finally, the invention provides a system and method for utilizing deliberately introduced reflections to obtain additional information, including fluid density.

Abstract: A composite acoustic wave device provides improved protection from environmental factors while maintaining high electrical characteristics and dynamic range is provided. The device comprises a rigid protector plate having high quality acoustical characteristics and a thickness which is a multiple of half wavelength of the resonant frequency. A piezoelectric plate is coupled to the protector plate, is supported therefrom, and forms an energy interface therewith. The piezoelectric and protector plates are dimensioned such that a wave of resonant frequency traveling between the excitation face and the loaded/sensing face, forms a substantially continuous-phase wave, at substantially peak amplitude, at the energy interface. By doing so the device decouples the electrical thickness of the wave device from the mechanical thickness thereof.

Abstract: Circularly polarized resonant structures are obtained utilizing piezoelectric resonators made of materials and orientations selected in accordance with the teaching provided herewith. Further provided are radially polarized structures. Furthermore, the utilization of such resonators and structures as sensors, for frequency control application, for signal filtering, and the like, is also disclosed.

Abstract: The current invention relates to a conductivity-dielectric (CD) electrode design with apertures that allow compressional waves to propagate away from the surface of the acoustic wave device unimpeded. This prevents reflection of compressional waves that would interact with the viscosity sensor surface, thus altering the device response. It allows compressional waves to pass through, and allows the dual mode viscosity sensor responses to be utilized for density/viscosity/elasticity measurement and correlation. The invention further offers methods of instrumentation to detect unwanted reflections, to compensate, and to correct for the distortions caused by reflections. Finally, the invention provides a system and method for utilizing deliberately introduced reflections to obtain additional information, including fluid density.

Abstract: Characterizing material properties using a simple and inexpensive measurement circuit is disclosed. It allows measurement of the transfer function change of an acoustic wave device without necessitating detailed knowledge of the resonant frequency, by integrating the transfer function. If one examines the integral of the transfer efficiency of an acoustic wave device as the acoustic wave is damped, one sees that the magnitude of the total signal transfer decreases with increasing damping allowing derivation of the material parameters from the results of simple integration.

Abstract: Acoustic sensing utilizing a bridge structure coupled about a portion of at least two sides of said bridge to a base substrate, wherein said bridge includes a piezoelectric section and has at least one active acoustic region proximate said bridge. A sensing material is disposed on at least a portion of at least one surface of the bridge, wherein the bridge produces stress effects measurable by an acoustic wave device located in the active acoustic region. According to one embodiment, the stress effects are measured by an acoustic wave device to sense a target matter. As target molecules accumulate on a sensing film affixed to at least a portion of the bridge, stress is produced in the bridge inducing a frequency change measured by an acoustic wave device.

Abstract: A coating providing high abrasion and chemical resistance composed of a barrier layer from vanadium, molybdenum, niobium, tantalum and the like, and an outer layer of diamond-like carbon. The coating is especially applicable for acoustic wave device (AWD) based sensors, and for passivating an electrode such as an electrode deposited on the AWD sensing area. The coating provides excellent mechanical and acoustical characteristics for coating acoustic wave devices allowing the sensor to operate in harsh environments.

Abstract: A coating providing high abrasion and chemical resistance composed of a barrier layer from vanadium, molybdenum, niobium, tantalum and the like, and an outer layer of diamond-like carbon. The coating is especially applicable for acoustic wave device (AWD) based sensors, and for passivating an electrode such as an electrode deposited on the AWD sensing area. The coating provides excellent mechanical and acoustical characteristics for coating acoustic wave devices allowing the sensor to operate in harsh environments.

Abstract: Circularly polarized resonant structures are obtained utilizing piezoelectric resonators made of materials and orientations selected in accordance with the teaching provided herewith. Further provided are radially polarized structures. Furthermore, the utilization of such resonators and structures as sensors, for frequency control application, for signal filtering, and the like, is also disclosed.

Abstract: A composite acoustic wave device provides improved protection from environmental factors while maintaining high electrical characteristics and dynamic range is provided. The device comprises a rigid protector plate having high quality acoustical characteristics and a thickness which is a multiple of half wavelength of the resonant frequency. A piezoelectric plate is coupled to the protector plate, is supported therefrom, and forms an energy interface therewith. The piezoelectric and protector plates are dimensioned such that a wave of resonant frequency traveling between the excitation face and the loaded/sensing face, forms a substantially continuous-phase wave, at substantially peak amplitude, at the energy interface. By doing so the device decouples the electrical thickness of the wave device from the mechanical thickness thereof.

Abstract: Acoustic sensing utilizing a cantilever structure coupled about at least one side of said cantilever to a base substrate, wherein said cantilever includes a piezoelectric section and has at least one acoustic wave device on a portion of the cantilever, wherein a flexure of the cantilever produces force-frequency effects measurable by the acoustic wave device. According to one embodiment, the cantilever sensor uses the flexure-frequency effect as measured by an acoustic wave device to sense a target matter. According to one embodiment, a sensing material is disposed on at least a portion of at least one surface of the cantilever.

Abstract: A coating providing high abrasion and chemical resistance composed of a barrier layer from vanadium, molybdenum, niobium, tantalum and the like, and an outer layer of diamond-like carbon. The coating is especially applicable for acoustic wave device (AWD) based sensors, and for passivating an electrode such as an electrode deposited on the AWD sensing area. The coating provides excellent mechanical and acoustical characteristics for coating acoustic wave devices allowing the sensor to operate in harsh environments.

Abstract: Acoustic sensing utilizing a bridge structure coupled about a portion of at least two sides of said bridge to a base substrate, wherein said bridge includes a piezoelectric section and has at least one active acoustic region proximate said bridge. A sensing material is disposed on at least a portion of at least one surface of the bridge, wherein the bridge produces stress effects measurable by an acoustic wave device located in the active acoustic region. According to one embodiment, the stress effects are measured by an acoustic wave device to sense a target matter. As target molecules accumulate on a sensing film affixed to at least a portion of the bridge, stress is produced in the bridge inducing a frequency change measured by an acoustic wave device.

Abstract: Acoustic sensing utilizing a cantilever structure coupled about at least one side of said cantilever to a base substrate, wherein said cantilever includes a piezoelectric section and has at least one acoustic wave device on a portion of the cantilever, wherein a flexure of the cantilever produces force-frequency effects measurable by the acoustic wave device. According to one embodiment, the cantilever sensor uses the flexure-frequency effect as measured by an acoustic wave device to sense a target matter. According to one embodiment, a sensing material is disposed on at least a portion of at least one surface of the cantilever.

Abstract: The invention is a method and apparatus for improving the aging, pressure sensitivity, and acceleration sensitivity of crystal resonators. In one embodiment the invention includes a coplanar two-dimensional compliant mounting structure, wherein the symmetry and compliance of the planar mounting structure reduces the effects of residual static stresses and dynamic vibratory stresses on the vibration sensitivity performance of a crystal resonator. The structural elements include compliance loops that provide relief from the effects associated with manufacturing, thermal and vibration stresses.

Abstract: The invention is a method and apparatus for improving the aging, pressure sensitivity, and acceleration sensitivity of crystal resonators. In one embodiment the invention includes a coplanar two-dimensional compliant mounting structure, wherein the symmetry and compliance of the planar mounting structure reduces the effects of residual static stresses and dynamic vibratory stresses on the vibration sensitivity performance of a crystal resonator. The structural elements include compliance loops that provide relief from the effects associated with manufacturing, thermal and vibration stresses.

Abstract: A method and apparatus for improving temperature stability of surface-launched acoustic wave sensors is described. The system includes a plurality of acoustic wave delay lines or resonators coated with identical films which are physically, chemically, biologically, or otherwise sensitive to one or more target chemical or biological analytes. At least one of the delay lines or resonators, referred to herein as reference channels, is used as a frequency reference to which the oscillation frequencies of the remainder of the delay lines or resonators, referred to as sensing channels, are compared. A thin coating of material that is preferably a passivation layer not sensitive to the analytes, is disposed upon the surface-launched acoustic wave sensor. The passivation layer covers sensing films on the reference channels, blocking or impeding interaction of the sensing films and the analytes thereby.