Abstract: An ultrasonic sensor, which is installed on a test device, includes a shell, one end is open, the other end is closed surface; a cover sheet, bonded to the open end of the shell; a copper foil, a lower surface of the copper foil is bonded to an inner bottom surface of the closed surface of the shell; a piezoelectric chip, a lower surface of the piezoelectric chip is bonded to a upper surface of the copper foil, and when the test device vibrates, the piezoelectric chip converts a vibration signal into a voltage response signal; a cable, a positive electrode is welded on a upper surface of the piezoelectric chip, and a negative electrode is welded on the upper surface of the copper foil, configured to connect to an external detection device and transmit the voltage response signal to the external detection device.

Abstract: A free piston Stirling refrigerator of the present invention has a cylinder provided inside a casing; a piston and a displacer that are provided in a way such that they are capable of reciprocating inside the cylinder; a linear motor for reciprocating the piston; and a control unit for controlling the operation of the linear motor. Particularly, the control unit has an inverter circuit for generating an alternating current with a given frequency and then supplying the alternating current to the linear motor; a current detection circuit for detecting the current outputted from the inverter circuit; and a control circuit for controlling the output from the inverter circuit based on a turbulence in the current detected by the current detection circuit. Thus, collisions between the piston and the displacer (i.e. hitting) can be restricted through an inexpensive configuration and a simple control.

Abstract: There are disclosed pressure-sensitive acoustic resonators and remote pressure sensing systems and methods. A pressure-sensitive acoustic resonator includes a conductor pattern formed on a planar surface of a dielectric substrate, the conductor pattern including an interdigital conductor pattern (ICP), and a diaphragm, the diaphragm being a portion of a plate of single-crystal piezoelectric material, the diaphragm having a front surface exposed to an environment and a back surface facing, but not contacting, the ICP.

Abstract: Provided is a pressure sensing device, which includes one or more pressure sensing sheet and a first substrate for supporting the pressure sensing sheet. The pressure sensing sheet is connected with the first substrate through welding, a welding spot of the welding is configured for deformation transfer and electrical signal transmission. The pressure sensing sheet includes a second substrate, at least one pressure sensing component, and a plurality of pads. The pressure sensing component is arranged at a lower surface and/or an upper surface of the substrate, the pads are arranged at the upper surface of the second substrate and are conductively connected with the pressure sensing component for deformation transfer and electrical signal transmission. The deformation is transferred to the substrate of the pressure sensing sheet through the pads when the pressure sensing device deforms.

Abstract: A SAW device includes a piezoelectric substrate, a support substrate which is located on a lower surface of the piezoelectric substrate and has a smaller thermal expansion coefficient than that of the piezoelectric substrate, an IDT electrode located on the piezoelectric substrate, a cover forming a space above the IDT electrode, and a plurality of first strip conductors which extend alongside each other on the cover and at least a part of which overlaps the space when viewed on a plane.

Abstract: An apparatus and method for measuring the internal pressure of a pipe or container is disclosed. The apparatus includes an acoustical transmitter (Tx1) mounted on a wall (1) of said pipe or container and a signal generator (2) connected to said transmitter and which is adapted to provide a signal to the transmitter. The signal from the transmitter is detected by two receivers (Rx1, Rx2) mounted on said pipe or container in a distance from said transmitter (Tx1). A processing unit (3) is connected to said transmitter and receivers, the processing unit being adapted to measure the travel time of an acoustical signal propagating between two receivers in the wall (i) and determine the pressure inside the pipe or container from said travel time.

Abstract: A surface acoustic wave sensor system for determining environmental conditions on a substrate. The system comprises an interrogator for producing an RF interrogating signal transmitted by an antenna to an interdigital transducer mounted on the substrate for producing an incident surface acoustic wave responsive to the interrogating signal. A plurality of reflector arrays mounted on the substrate produce a like plurality of reflected surface acoustic waves; a spacing between adjacent ones of the plurality of reflector arrays comprising a non-uniform distance. The plurality of reflected surface acoustic waves are responsive to the environmental condition and exhibit a characteristic from which the environmental condition can be determined by a processing component.

Abstract: A sensor arrangement comprises a first sensor element for converting a physical quantity into a first electrical signal and at least a second sensor element for converting said physical quantity into a second electrical signal. The first sensor element has a first sensitivity while said second sensor element has a second sensitivity different from said first sensitivity.

Abstract: A wireless measurement device includes a sound acoustic wave (SAW)-based micro sensor converting a wirelessly received pulse signal into an SAW and generating a plurality of pulse signals by reflecting the SAW, and wirelessly transmitting the plurality of pulse signals to measure a variance of an environmental element; and a reader generating and wirelessly transmitting a pulse signal to the SAW-based micro sensor to measure variances in environmental elements.

Abstract: A pressure and temperature sensor comprising comprises at least a first resonator of the SAW type comprising a piezoelectric substrate, thinned at least locally, of the membrane type, a second resonator of the SAW type comprising a piezoelectric substrate and a third resonator of the SAW type comprising a piezoelectric substrate, characterized in that the first, the second and the third resonators are respectively on the surface of first, second and third individual piezoelectric substrates, each of the individual substrates being positioned on the surface of a common base section, locally machined away under said first resonator in such a manner as to liberate the substrate from said resonator so as to render it operational for the measurement of pressure. A method of fabrication for such a sensor is also provided.

Abstract: Disclosed is detecting changes in pressure in a medium, with an optical fiber having a core diameter at an immersion surface contact of the fiber of less than 10 ?m; a layer of material deposited on said end of the fiber, the material being of a thickness of from about 2 nm to about 10 nm. Also disclosed is detecting pressure waves in a medium comprising: contacting the medium with a fiber optic, the fiber integrated with a light source and a detector, the fiber optic having a diameter of less than 10 ?m at an immersion surface contact of the fiber; providing a thin layer of material on the immersion surface contact, wherein said thin layer of material is of a thickness in a range of from about 2 nm to about 10 nm; and detecting Fresnel back reflections from the immersion end of the fiber.

Abstract: A pressure sensor includes: a supporting body which has an opening; a pressure detecting portion which includes a supporting film provided on the supporting body and having a diaphragm portion closing the opening, and a piezoelectric body provided on the diaphragm portion and deflecting to output an electric signal; a frame body which has, on the pressure detecting portion, a cylindrical cavity along a film thickness direction of the supporting film, and is formed, in plan view when viewed from the film thickness direction of the supporting film, at a position where a cylindrical inner peripheral wall of the cavity overlaps with the opening, or outside of the opening; a sealing film which closes the frame body; and a silicone oil which is filled in an inner space formed of the cylindrical inner peripheral wall of the cavity, the sealing film, and the pressure detecting portion.

Abstract: A pressure detecting device includes: a resonator whose oscillation frequency varies depending on a pressure; a first oscillation circuit that oscillates the resonator and outputs a signal of a frequency corresponding to the pressure; an AT-cut quartz crystal resonator; a second oscillation circuit that oscillates the AT-cut quartz crystal resonator and outputs a reference clock signal; a measuring unit that measures the reference clock signal by the use of a reciprocal counting method; a temperature detecting unit that detects a temperature of the resonator; and a storage unit that stores coefficients of a first approximating polynomial for calculating a first correction value used to compensate for a frequency-temperature characteristic of the measuring unit, wherein the frequency-temperature characteristic of the value measured by the measuring unit includes a frequency-temperature characteristic of the AT-cut quartz crystal resonator and a frequency-temperature characteristic of the resonator.

Abstract: A pressure transducer assembly for measuring pressures in high temperature environments employing an elongated tube which is terminated at one end by an acoustic micro-filter. The micro-filter is operative to absorb acoustic waves impinging on it with limited or no reflection. To improve the absorption of acoustic waves, the elongated tube may be tapered and/or mounted to a support block and further convoluted to reduce the overall size and mass of the device. A pressure transducer with a diaphragm flush may be mounted to the elongated tube and extend through to the inner wall of the tube. Hot gases propagate through the elongated tube and their corresponding pressures are measured by the transducer. The acoustic filter operates to absorb acoustic waves resultant from the hot gases, therefore enabling the pressure transducer to be mainly responsive to high frequency waves associated with the gas turbine operation.

Abstract: A combined pressure and temperature sensor comprising a tubular member 3 of circular cross section having a closed end and an open end, the open end, in use, connecting to a pressurized environment such that the interior of the tubular member is exposed to the pressure, a flat or preferably a symmetrical distribution of flats 1 being formed on the outer cylindrical surface of the tubular member 3, and a sensor element 2 mounted on at least one said flat 1, which sensor element 2 is sensitive to the strains in the tubular wall of the tubular member 3 resulting the pressure in the interior thereof and the temperature of said tubular member.

Abstract: An ultrasonic pressure sensor and a method of detecting ultrasonic pressure. In one embodiment, the ultrasonic pressure sensor includes: (1) an interferometer having a reference arm and a signal arm that includes a probing fiber, the probing fiber having a reflective coating at a distal end thereof and configured to couple to ultrasonic waves proximate the distal end, the interferometer configured to receive laser light and produce two output beams based on the ultrasonic waves and (2) a photodetector coupled to the interferometer and configured to generate electronic signals based on the two output beams.

Abstract: A method of manufacturing a pressure monitoring package comprises the steps of mounting a plurality of resonators onto a substrate 1, mounting the substrate 1 in a package base 11, mechanically constraining the package base 11 within a mechanical preloading jig, and adjusting the preload using the jig whilst measuring the frequency of the SAWs until the required frequency is obtained. A lid 7 is then welded onto the package base 11 using a laser welder, after which the preload frequency of the package 10 is fine tuned by using the laser welder to produce laser marks 21-28, 31-38 on the outside of the package 10.

Abstract: The present invention relates to an apparatus for measuring pressure inside a predetermined vessel based on the principle that the transmitting efficiency of ultrasonic waves is changed by acoustic impedance variation according to an internal pressure. The apparatus includes an ultrasound exciting unit 20 disposed inside the vessel 10 and generating predetermined ultrasonic waves, an ultrasound receiving unit 30 disposed inside the vessel 10 and placed on the same axis line as that of the ultrasound exciting unit 20, a control unit 70 for controlling a frequency and a waveform of the excitation signal transmitted into the ultrasound exciting unit 20, and a pressure measuring unit 80 for measuring an internal pressure of the vessel 10 based on an ultrasonic signal received by the ultrasound receiving unit 30 and the excitation signal transmitted into the ultrasound exciting unit 20.

Abstract: A pressure sensor for use in measuring the pressure within fluids. The sensor comprises a medium whose material has a low coefficient of thermal expansion. The pressure can be measured by observing how signals pass through the medium at some unknown pressure and then comparing the observations to how the signals pass through the medium at a known pressure. The signals can be acoustic waves or light waves.

Abstract: The invention relates to a pressure sensor, the measuring cell of which is provided with at least one membrane for the protection of the pressure-sensitive element and a measuring chamber, filled with pressure medium, in which the pressure-sensitive element is housed. According to the invention, the membrane is monitored for damage, whereby at least one surface wave sensor is arranged in the chamber filled with pressure medium. On damage to the membrane occurring, process medium is mixed with the pressure medium. A substance change in the sensitive region of the surface wave sensor is thus brought about which results in a differing signal run time. Any change in run time is an indictor of damage to the pressure sensor and may be signaled as such.

Abstract: The present invention aims to provide a delay device having an analog delay line adaptable to a plurality of frequencies with a less number of taps. The analog delay line has a maximum delay amount equivalent to a wavelength from over a ? wavelength of a predetermined maximum wavelength of an input signal to under a 1 wavelength thereof. Tap intervals up to a delay point equivalent to ½ of a predetermined minimum wavelength of the input signal are different from tap intervals placed ahead of those. The maximum wavelength is a wavelength of a signal having a frequency of 2 MHz, for example, and the minimum wavelength is a wavelength of a signal having a frequency of 5 MHz, for example.

Abstract: Tunable vibration energy scavengers and methods of operating the same are disclosed. The disclosed energy scavengers comprise a beam with a main body, wherein the beam comprises at least one flap and means for changing a shape of the at least one flap, wherein the at least one flap is physically attached to the main body along a longitudinal side of the main body. The disclosed methods comprise tuning the shape of the at least one flap, thereby tuning the stiffness of the structure.

Abstract: The present invention relates to an apparatus for measuring pressure inside a predetermined vessel based on the principle that the transmitting efficiency of ultrasonic waves is changed by acoustic impedance variation according to an internal pressure. The apparatus includes an ultrasound exciting unit 20 disposed inside the vessel 10 and generating predetermined ultrasonic waves, an ultrasound receiving unit 30 disposed inside the vessel 10 and placed on the same axis line as that of the ultrasound exciting unit 20, a control unit 70 for controlling a frequency and a waveform of the excitation signal transmitted into the ultrasound exciting unit 20, and a pressure measuring unit 80 for measuring an internal pressure of the vessel 10 based on an ultrasonic signal received by the ultrasound receiving unit 30 and the excitation signal transmitted into the ultrasound exciting unit 20.

Abstract: A method and apparatus for determining at least one characteristic of a fluid flowing within a pipe is provided. The fluid flow may include one or more liquid component bodies and one or more gas component bodies, which bodies occupy a substantial cross-sectional area of the pipe when passing a location in the pipe. The method includes, and the apparatus includes elements operable to perform, the steps of: 1) transmitting a signal into the fluid flow at the location within the pipe, and receiving the signal after it has traversed at least a portion of the fluid flow; 2) determining a time of flight of the signal traversing the fluid flow; 3) determining the presence of a liquid component body at the location in the pipe, using the determined time of flight; and 4) determining at least one characteristic of the fluid using fluid data generated if the liquid component body is present at the location.

Abstract: The invention relates to a pressure sensor, the measuring cell of which is provided with at least one membrane for the protection of the pressure-sensitive element and a measuring chamber, filled with pressure medium, in which the pressure-sensitive element is housed. According to the invention, the membrane is monitored for damage, whereby at least one surface wave sensor is arranged in the chamber filled with pressure medium. On damage to the membrane occurring, process medium is mixed with the pressure medium. A substance change in the sensitive region of the surface wave sensor is thus brought about which results in a differing signal run time. Any change in run time is an indictor of damage to the pressure sensor and may be signaled as such.

Abstract: A combined pressure and temperature sensor comprising a tubular member 3 of circular cross section having a closed end and an open end, the open end, in use, connecting to a pressurised environment such that the interior of the tubular member is exposed to the pressure, a flat or preferably a symmetrical distribution of flats 1 being formed on the outer cylindrical surface of the tubular member 3, and a sensor element 2 mounted on at least one said flat 1, which sensor element 2 is sensitive to the strains in the tubular wall of the tubular member 3 resulting the pressure in the interior thereof and the temperature of said tubular member.

Abstract: An ultrasonic pressure sensor and a method of detecting ultrasonic pressure. In one embodiment, the ultrasonic pressure sensor includes: (1) an interferometer having a reference arm and a signal arm that includes a probing fiber, the probing fiber having a reflective coating at a distal end thereof and configured to couple to ultrasonic waves proximate the distal end, the interferometer configured to receive laser light and produce two output beams based on the ultrasonic waves and (2) a photodetector coupled to the interferometer and configured to generate electronic signals based on the two output beams.

Abstract: A protected resonating sensor may include at least one resonating sensor unit, each sensor unit has one or more vibratable members. The protected sensor includes at least one body of gel for protecting the vibratable member(s) of the sensor. The gel may be disposed on or attached to the sensor unit(s) covering the vibratable member(s) of the sensor unit(s). The gel may also be disposed in an open housing including one or more sensor units, and may cover vibratable members of different sensor units. The sensor unit may be any resonating sensor unit having a resonance frequency that depends on the value of a physical variable in a measurement environment. The protected sensor may also be attached to or included in or formed as part of any suitable device or sensor anchoring device and may also be implanted or inserted into a body or an organism. Methods are described for constructing the gel-protected sensor.

Abstract: An absolute pressure sensor is provided comprising a vibration sensing element such as a piezoelectric element disposed on a vibratable seal. The seal is disposed between two gas spring chambers which are maintained at substantially ambient pressure. The resonant vibration frequency of the seal changes and is proportional with the pressure in the gas spring chambers such that the electrical output of the piezoelectric element will be proportional to the vibration frequency. The frequency of the output of the piezoelectric element is read using suitable electronic circuitry and compared to a set of predetermined pressure/frequency data for calculation of a pressure value.

Abstract: The invention relates to an economical pressure measuring device as well as to a favorable method for pressure determination, with which a pressure measurement can be performed from outside the high-pressure container. To that end, the device comprises an ultrasound transmitter mounted outside the pressure container and an ultrasound receiver by means of which transmitter and receiver the transit time of an ultrasonic pulse traveling through the liquid contained in the high-pressure container can be ascertained, and the method comprises generating an ultrasonic pulse outside the high-pressure container measuring the time that the ultrasonic pulse requires to traverse a defined distance calculating the pulse speed of the pulse in the liquid; and from that determining the pressure in the liquid.

Abstract: A sensor hard to break and capable of improving sensitivity is obtained. This sensor comprises an electrode plate and a diaphragm, opposed to the electrode plate, including a first elastic film arranged on a central portion and a second elastic film, arranged at least on a peripheral portion of the first elastic film, made of a material having a lower elastic modulus than the first elastic film.

Abstract: Many sensors could be used in a passive wireless mode. These include RLC, acoustic wave and magneto-elastic sensors. These types of sensors are designed to exhibit a change in fundamental frequency when exposed to environmental factors such as temperature, pressure, or chemicals. An interrogation circuit can inductively couple to the sensor and measure the change in fundamental frequency. The change can be used to measure the environmental factor. Sensor sensitivity and inductive coupling efficiency can be competing design constraints. A driver, electrically connected to the sensor and inductively coupled to the interrogation circuit, can relax the constraints. The driver, however, can introduce noise into the sensor. The sensor can be shielded using physical and geometric techniques to reduce the noise.

Abstract: Thickness of a pressure-detecting piezoelectric substrate (2) that is thinner than that of a supporting piezoelectric substrate (3) and that has a surface acoustic wave element for pressure detection (7a) on its lower surface is mounted on the supporting piezoelectric substrate (3) having a surface acoustic wave element for reference (4a) on its upper surface. A sealing member (5) is provided between the supporting piezoelectric substrate (3) and the pressure-detecting piezoelectric substrate (1). The surface acoustic wave element for pressure detection (7a) and the surface acoustic wave element for reference (4a) can be disposed in a space (S) enclosed with the pressure-detecting piezoelectric substrate (1) and the sealing member (5). It is possible to provide a small-sized pressure sensor device (1) that can perform temperature compensation and that has high reliability.

Abstract: A sensor and insertion assembly 2 is used for intravascular measurement of pressure in a living body. The assembly includes, a sensor chip 6 having a substrate body 8 with a recess covered by a pressure sensitive film 10 thereby forming a cavity 12. A piezoelectric element, preferably in the form of a piezoelectric film 14, is arranged in connection with the pressure sensitive film, and energy is applied to the piezoelectric element such that acoustic waves are generated in the element. The piezoelectric element is arranged to generate an output signal, representing the pressure at the film, in dependence on the measured properties of the acoustic waves related to the deflection of the pressure sensitive film.

Abstract: A Pressure Sensing Apparatus is disclosed. Also disclosed is an apparatus that provides increased pressure sensitivity without added cost and complexity in the electronic detector circuitry. The apparatus further is less sensitive to gravity, vibrations or other external influences. It is a still further object that the apparatus be available with a curved bellow head, formed with either concave or convex reflective surfaces. Other versions of the apparatus may have a deflectable focusing diaphragm that permits pressure detection responsive to the curvature of a diaphragm in response to pressure differentials across the diaphragm.

Abstract: Disclosed is a pressure measuring system for a vacuum chamber, in particular, a pressure measuring system for a vacuum chamber using ultrasonic wave. In this regard, there is provided a pressure measuring system for a vacuum chamber using ultrasonic wave, comprising a vacuum chamber 10 formed with desired vacuum at the inside thereof; ultrasonic wave-emitting means mounted close to an outer peripheral surface of the vacuum chamber 10 for emitting an ultrasonic wave 62 to the inside of the vacuum chamber 10; ultrasonic wave-receiving means for receiving a reflection wave 64 reflected after the striking of the ultrasonic wave 62 emitted from the ultrasonic wave-emitting means to the vacuum chamber; reflection wave-detecting means for detecting the reflection wave 64 from the ultrasonic wave-receiving means; and amplitude-analyzing means for analyzing the amplitude of the reflection wave 64 detected by the reflection wave-detecting means.

Abstract: A wireless sensor is disclosed, which includes a substrate upon which the wireless sensor can be configured. The wireless sensor includes a plurality of surface acoustic wave (SAW) sensing elements configured in parallel with one another upon the substrate, wherein one or more of the SAW sensing elements is responsive to a wireless frequency range that differs from that of a wireless frequency range of at least one other SAW sensing element among the group of SAW sensing elements. It is this parallelism that permits all of the SAW sensing elements to receive the same strain when pressure is applied thereon. In doing so, the capability for three separate interrogators to measure strain is provided.

Abstract: A surface acoustic wave (SAW) sensor and an interrogator that transmits a noise source to the sensor for receiving an interrogation signal that is processed and compared to the source signal provides pressure and temperature measurements. One SAW sensor a single interdigital transducer serving as both an input and an output transducer for generating and detecting a SAW, and coded reflectors in a mirrored arrangement opposing the single interdigital transducer. The piezoelectric substrate is supported in a hermetically sealed package such that pressure on the package causes distortion of the substrate transducer surface and thus SAW velocity changes that reflect changes in pressure. Characteristic temperature coefficients of delay for the substrate are directly translated into a temperature value.

Abstract: An ultrasonic pulse/echo measurement arrangement includes an ultrasonic transducer (12), which is mounted spatially fixed on an air spring cover plate (4). The arrangement further includes a fixedly mounted reference reflector (14), a target reflector (16) mounted on a roll-off piston (8) or on the bumper (18) as well as a transmitter/receiver evaluation electronic circuit (30). The running time as well as the amplitude of the reference signal is evaluated to precisely determine the pressure present in the interior space of the air spring. The ultrasonic transducer (12) has a ?/4-adaptation layer (22), whose impedance does not correspond to the geometric mean of the impedances of the ultrasonic transducer (12) and the ambient air of the interior space (20) of the air spring, but rather, is a mismatch. The evaluation electronic circuit (30) can be calibrated at ambient pressure for the determination of the inner pressure of the air spring.

Abstract: Methods and systems for determining the resonance frequency of a resonator, using the Doppler effect. An interrogating sonic beam including a carrier frequency and one or more resonator exciting frequencies is directed at a resonator disposed in a measurement environment. Resonator vibrations are excited by the resonator exciting frequencies. The carrier frequency is modulated by the vibrating part(s) of the resonator. The returning signal is received and analyzed to determine the amplitude of the Doppler shifted sideband frequencies. The resulting data is processed to determine the resonator's resonance frequency. Using calibrated resonating sensors having a resonance frequency that varies as a function of a physical parameter in a measurement environment, the method and systems allow determining the value of the physical variable from the sensor's resonance frequency.

Abstract: The invention relates to a testing device for ultrasonic bar (30) testing, comprising a container (20) a) with a chamber disposed therein where the ultrasonic testing is carried out which b) is provided with at least one through-passage (28) for bars which are to be tested and which c) has at least one inlet and at least one outlet for a coupling fluid (52), especially water, whereby the inlet and outlet are arranged in such a way the coupling fluid (52) is circulated around the bar (30) in a cross-wise direction in relation to the longitudinal direction thereof (32), in addition to comprising at least one ultrasonic test head (46) which is directed at the bars (30). The chamber has a non-circular cross-section perpendicular to the longitudinal direction (32) of the bars (30) and the cross-section of the chamber is adapted to the profile of the bars (30) in such a way that the width of a gap (42) running between the bars (30) and the wall (40) of the chamber is substantially maintained.

Abstract: A system and method for regulating the temperature of a sensor to reduce temperature gradients that form within the sensor. In one embodiment, the temperature gradients are reduced utilizing a temperature regulator with two controlled zones that surround a variable capacitance sensor. Measurements are made for the ambient temperature of at least one of the two temperature controlled zones, and the temperature differential between the two temperature controlled zones. The temperature regulator then adjusts the temperature of the two controlled zones based upon this differential in order to minimize the existing temperature gradient.

Abstract: A thermal detecting device can be used to detect standing waves in a tire. A one degree F. differential has been found to exist between the high flexing points and the low flexing points in a standing wave, and thermal imaging can be used to map the wave. Information on the standing waves can be used by the tire designer to improve a design.

Abstract: A system for monitoring the flow of a fluid such as water in a pipe, including a remote pressure sensor operably connected to the pipe for sensing the pressure of the fluid at the location of the pressure sensor. An acoustic transmitter is placed proximate the remote pressure sensor for transmitting the output of the sensors by an acoustic signal transmitted through the fluid in the pipe to an acoustic receiver that generates a control signal in response thereto control a pressure control valve for adjusting the pressure in the pipe in response. The system is intended for a water distribution networks that include a plurality of pipes, with a remote pressure sensor, transmitter, receiver and control device for at least some of the plurality of pipes.

Abstract: Magnetic force from a momentarily excited coil (34) results in oscillatory flexure of a flexible diaphragm (30) loaded on one side by a liquid (10) whose level is to be measured. A permanent magnet (42) mounted on the diaphragm (30) so moves with diaphragm flexure as to vary the magnetic saturation of a saturable circuit in which the coil (34) generates flux. By determining the coil's inductance under quiescent-diaphragm conditions, a computer (56) can infer the ambient pressure that bears upon the liquid (10). By compensating for the static pressure thus inferred, it can then determine liquid level by observing diaphragm oscillations reflected in coil electromotive force generated by the magnet (42) as the diaphram (30) undergoes oscillatory flexure in response to the coil's momentary excitation.

Abstract: A pressure- and temperature-sensitive transducer comprises a tubular housing, a resonator located within the housing and end caps closing the ends of the housing. The resonator is located in a radial plane with respect to the housing and is connected to the housing by two separate connecting regions. The housing, resonator and connecting, regions are formed from a single piece of double rotation cut quartz. The shape, dimensions and position of the connecting regions is chosen to optimize stress in an axis responsive to changes in pressure and temperature while minimizing stress in an axis responsive predominantly to pressure.

Abstract: A pressure and temperature transducer includes an elongate housing formed from double rotation cut crystal quartz, an elongate plate-like resonator formed from double rotation cut crystal quartz capable of vibrating under an applied electric field located within the housing, the resonator being formed in unitary construction with the housing. The long edges of the resonator are connected to the interior walls of the housing, and short edges of the resonator are free and extend across the interior of the housing in a substantially continuous curve. Electrodes are located on opposite faces of the resonator for applying an electric field which causes the resonator to vibrate. End caps, formed from double rotation cut crystal quartz, are provided at each end of the housing. A borehole tool includes a tool body which can be positioned in a borehole, a probe for sampling fluid in the borehole; and a pressure and/or temperature transducer, connected to the probe for making measurements on the fluid.

Abstract: A method and an apparatus for integrating a surface acoustic wave (SAW) filter and a transceiver are provided to solve the problem of having a large area of the prior-art integration of a SAW filter and a transceiver; wherein a device for integrating a SAW filter and a transceiver is provided and a component stack method is used to accomplish the integration of the SAW filter and the transceiver, and thus besides featuring a low cost and a small area as well as avoiding a signal loss, the invention can further include a design of encapsulating other components and chips, or even suitable to be used for various integrated circuit packaging technologies (such as QFP and BGA, etc.

Abstract: A surface or bulk acoustic wave device can be implanted in or worn on a human or animal body to monitor various parameters thereof. The device comprises a pair of interdigitated transducers spaced apart over the surface of a piezo-electric substrate that is exposed to the parameter to be monitored. The device is interrogated by a radio-frequency signal being supplied to one of the transducers and detected after reflection by the other transducer. The parameter is measured by comparison of the supplied and received signals.

Abstract: A surface or bulk acoustic wave device can be implanted in or worn on a human or animal body to monitor various parameters thereof. The device comprises a pair of interdigitated transducers spaced apart over the surface of a piezo-electric substrate that is exposed to the parameter to be monitored. The device is interrogated by a radio-frequency signal being supplied to one of the transducers and detected after reflection by the other transducer. The parameter is measured by comparison of the supplied and received signals.