Having Sonic Sensor Patents (Class 340/621)
  • Patent number: 5264831
    Abstract: To determine and/or monitor a predetermined contents level in a container, at the height of the level to be monitored a region of the container wall is defined by a ring or frame which is attached to the outer side of the container wall in such a manner that it is in oscillatory mechanical connection with said container wall. The region of the container wall enclosed by the ring or frame forms the diaphragm of a sensor which also comprises an electromechanical excitation transducer which when fed with an electrical voltage sets the defined diaphragm region into oscillations, and an electromechanical receiving transducer which converts the oscillations of the defined diaphragm region to an electrical AC voltage. An evaluating circuit connected to the receiving transducer serves to initiate display and/or switching operations in dependence upon the frequency, the phase or the amplitude of the AC voltage emitted by the receiving transducer.
    Type: Grant
    Filed: March 11, 1991
    Date of Patent: November 23, 1993
    Assignee: Endress u. Hauser GmbH u. Co.
    Inventor: Helmut Pfeiffer
  • Patent number: 5247832
    Abstract: In a vibrator-type level sensor, a detection pipe (14) is provided projecting from a base unit (1) to be mounted to a wall of a container (8) containing a substance (100) to be detected. The detection pipe (14) has an internal vibration plate (12) attached with a vibrating piezo-electric device (16) thereon and the internal vibration plate (12) is mechanically connected through an end cap (13) to the free end of the detection pipe (14, 140) to form a folded cantilever unit (30) which responds when the end cap (13) or pipe (14) are contacted by the material being sensed in the container.
    Type: Grant
    Filed: February 14, 1992
    Date of Patent: September 28, 1993
    Assignee: Nohken Inc.
    Inventors: Takayuki Umezawa, Takao Kawakita
  • Patent number: 5195058
    Abstract: This disclosure concerns the application of the pulse echo principle to the non-intrusive method of low liquid level sensing to determine the level of a liquid in a container. Generally, the sensor is attached to an outer wall of a liquid container by means of an epoxy adhesive. An ultrasonic pulse is transmitted through from the sensor into the container and is reflected back through the epoxy adhesive and the container wall. The acoustic reflection coefficient for the container wall varies depending on whether the wall is backed by a liquid, the level of which is being determined. Specific integral equations which are provided to manipulate the data and to render the sensor less sensitive to noise, wall thickness and reflections from thin liquid levels.
    Type: Grant
    Filed: April 30, 1992
    Date of Patent: March 16, 1993
    Assignee: The United States of America as represented by the Secretary of the Air Force
    Inventor: Wayne E. Simon
  • Patent number: 5192933
    Abstract: A detector for detecting the presence or absence of an ultrasonically conductive medium such as a liquid within a container includes a transducer that generates and transmits an energy burst through a first wall of the container toward the opposing wall of the container. The frequency at which the energy burst is transmitted is selected so that the energy burst is greatly attenuated when it travels through air and is not greatly attenuated when it travels through liquid. The detector includes a window generator that generates an electronic window corresponding to a predetermined period of time during which the detector expects to receive an echo of the energy burst. If an echo is received during the window, then liquid is present in the container, whereas no liquid is present if no echo is received. The position of the window may be changed via a dial having discrete settings to accommodate pipes of different diameters.
    Type: Grant
    Filed: June 14, 1990
    Date of Patent: March 9, 1993
    Inventor: Al W. Rodriguez
  • Patent number: 5191795
    Abstract: An ultrasonic detector for detecting air in a fluid passage is disclosed. The detector comprises a transmitting crystal and complementary receiving crystal disposed around the fluid passage. A sweep oscillator is used to apply a variable-frequency signal to drive the transmitting crystal into resonance so that a burst of ultrasonic energy is released therefrom. The swept frequency range encompasses the resonant frequency of the transmitting crystal, ensuring that it resonates. If there is fluid in the passage, the ultrasonic energy causes a relatively high voltage to develop across the receiving crystal. Air in the passage attenuates transmission of the ultrasonic energy so that a low voltage signal is developed across the receiving crystal. A sensor circuit connected to the receiving crystal monitors the signal developed thereacross and in response to the magnitude of the signal, asserts a signal that indicates whether there is air or fluid in the passage.
    Type: Grant
    Filed: August 23, 1991
    Date of Patent: March 9, 1993
    Assignee: Abbott Laboratories
    Inventors: George H. Fellingham, Lance B. Koll, Timothy J. Hughes
  • Patent number: 5191316
    Abstract: The apparatus comprises at least two oscillating rods which are secured spaced from each other to a diaphragm, the edge of which is connected to a screw-in piece. On the side of the diaphragm remote from the oscillating rods a clamping screw is fixedly connected to the diaphragm so that the clamping screw and diaphragm assume a position with respect to each other in which the axes of symmetry coincide. The clamping screw is surrounded by a stack of annular piezoelectric elements, electrode rings and insulating rings. The stack forms the excitation and receiving transducer of the apparatus. The stack-shaped excitation and receiving transducer is clamped and secured between the diaphragm and a hexagonal nut. The stack bears on pressure studs which are arranged between a metal ring terminating the stack and the diaphragm. The clamping force is chosen so that the diaphragm is simultaneously concavely prestressed.
    Type: Grant
    Filed: May 20, 1991
    Date of Patent: March 2, 1993
    Assignee: Endress u. Hauser GmbH u. Co.
    Inventor: Volker Dreyer
  • Patent number: 5155472
    Abstract: A liquid level sensing device having a transducer in which successive bursts of pulses of ultrasonic energy are transmitted across a gap. When liquid is present in the gap the bursts of pulses are received and signal processed to indicate the presence of liquid in the gap.
    Type: Grant
    Filed: July 14, 1986
    Date of Patent: October 13, 1992
    Assignee: Introtek International, Inc.
    Inventor: Naim Dam
  • Patent number: 5128656
    Abstract: A level detecting method and apparatus wherein a tubular member with one end open has a stationary wave generating means located within the tubular member. The stationary wave generating means generates stationary waves having a node or antinode at the open end, whereby a switching signal is provided when the open end of the tubular member is completely closed by a measuring object or when the measuring object approaches the open end.
    Type: Grant
    Filed: August 28, 1990
    Date of Patent: July 7, 1992
    Assignee: Kansai Automation Co., Ltd.
    Inventor: Kajiro Watanabe
  • Patent number: 5121340
    Abstract: A multi-level probe for sonic range measurements utilizes a plurality of parallel reflectors that each include an opening arranged coaxially about a beam of ultrasonic energy transmitted along a reference axis from an associated transducer. The opening in each reflector permits most of the sonic energy to pass to a subsequent reflective surface, while the periphery about the opening provides echo signals for determining physical conditions in the environment through which the sonic energy has passed. A novel system is used for determining physical conditions that are a function of time differences between signals from different reflectors, calculated with a highly efficient digital signal processing algorithm.
    Type: Grant
    Filed: June 8, 1990
    Date of Patent: June 9, 1992
    Assignee: Campbell Scientific, Inc.
    Inventors: Eric Campbell, Gaylon Campbell, Jeff Norton, Art Heers
  • Patent number: 5099454
    Abstract: The detector for detecting the presence of a liquid comprises: a) a metal veguide having a solid cylindrical top first portion of relatively small section with an outside diameter having a first value d1, which first portion is fixed on a support, a cylindrical rigid bottom second portion whose outside diameter has a second value d2 greater than the first value d1, which second portion extends the first portion downwards and is connected thereto by a short linking portion; b) transducer means disposed in the vicinity of the top portion of the waveguide; and c) electronic processing means. The value of the frequency at which the transducer means are excited is selected in such a manner that acoustic wave trains propagate in the cylindrical first portion at the group velocity of low frequency waves, and propagate in the cylindrical second portion at the minimum group velocity corresponding to the point of inflection in the curve of phase velocity as a function of frequency.
    Type: Grant
    Filed: July 19, 1990
    Date of Patent: March 24, 1992
    Assignee: Materiel et Auxiliaire de Signalisation et de Controls pour l'Automation
    Inventors: Eugene Dieulesaint, Daniel Royer, Olivier Legras
  • Patent number: 5095747
    Abstract: Method and apparatus for measuring the level of a cryogenic liquid in a container using frequency pulses. The time interval between the transmitted and echoed pulse is measured and compared with predetermined store values which are characteristics of the container of known geometry.
    Type: Grant
    Filed: December 26, 1989
    Date of Patent: March 17, 1992
    Assignee: Barnstead Thermolyne Corporation
    Inventor: Dennis H. Smith
  • Patent number: 5085077
    Abstract: An ultrasonic liquid level detector mounted in a fill pipe cap. The ultrasonic detector mounted in a fill pipe cap (10) is used in determining a level and/or the volume of a liquid (5) stored in an underground storage tank (20). The fill pipe cap contains an ultrasonic ranging unit (50) that measures a time, T.sub.L, required for an ultrasonic pulse to travel round trip between an ultrasonic transducer/receiver (54) and the surface of the liquid in the tank. A reference reflector (25) disposed within a fill pipe (30) is used in determining a reference time, T.sub.R, that is included in a non-linear expression, e.sup..alpha. .multidot.T.sub.L.sup..beta..sbsp.1 .multidot.T.sub.R.sup..beta..sbsp.2, in order to compute the level of liquid in the storage tank. The terms e.sup..alpha., .beta..sub.1, and .beta..sub.2 comprise a correction for errors in the round-trip times T.sub.L and T.sub.R caused by a non-uniform vapor density of the liquid along the path traveled by the ultrasonic pulses.
    Type: Grant
    Filed: January 7, 1991
    Date of Patent: February 4, 1992
    Assignee: Capscan Sales Incorporate
    Inventors: Charles E. Stapleton, Jerauld T. Numata
  • Patent number: 5062295
    Abstract: An accurate measurement of liquid levels in a tank are made using a dual tube sonic level gage. This uses plane waves of sound, in air, propagated in two vertical tubular wave guides to locate the levels of liquid contained in each tube. One tube has slots at the bottom and allows both the light (upper) and the heavy (lower) liquids to be present inside the tube at the same level as outside (i.e. in the tank). The other tube allows only the lower liquid to enter it. In the application for a measurement of gasoline and water levels in a tank, levels outside the tube (i.e. in the tank) are calculated using the equations of hydrostatics. Corrections due to temperature need not be made in order to obtain levels accurate to 1 percent.
    Type: Grant
    Filed: December 24, 1990
    Date of Patent: November 5, 1991
    Assignee: Sparktech
    Inventors: Parthasarathy Shakkottai, Eug Y. Kwack
  • Patent number: 5060484
    Abstract: An ultrasonic bin level control circuit which employs a fail-safe circuit to shut off a compressor when echoes are late or absent, and a transducer mounting system which facilitates installation and removal of a transducer for servicing and cleaning. A level detector compares a reference signal with a reflected signal, the ice reaching a desired level when the reflected signal overlaps the reference signal. When the desired level is reached, the reference signal is modified through feedback to prevent short cycling of the compressor. The transducer is installed within a cylindrical housing which is easily installed and removed from a cylindrical socket within a compartment above the bin.
    Type: Grant
    Filed: June 12, 1990
    Date of Patent: October 29, 1991
    Assignee: Scotsman Group, Inc.
    Inventors: Vincent N. Bush, Gregory L. Griswold
  • Patent number: 5053747
    Abstract: An ultrasonic air-in-line detection system for use in detecting air bubbles in the fluid line of a disposable cassette mounted on a main pump unit is disclosed in which a self-test procedure is periodically used to ensure that any faults in the ultrasonic air-in-line detector which do not fail safe are automatically detected. After a pumping cycle is completed, if the ultrasonic air-in-line detector indicates that there is fluid in the fluid line at the location of the ultrasonic sensor, the operating frequency of the transmitting ultrasonic transducer is changed to a non-resonant frequency for the self-test procedure. If the ultrasonic air-in-line detector still produces a signal indicating that there is fluid in the line, this indicates that there is a failure in the ultrasonic detector and a fault is indicated and the system is shut down.
    Type: Grant
    Filed: September 5, 1989
    Date of Patent: October 1, 1991
    Assignee: Pacesetter Infusion, Inc.
    Inventors: John B. Slate, James L. Henke
  • Patent number: 5043912
    Abstract: An apparatus for measuring the level of the interface between two different media in a reservoir comprises a vibratory element adapted to contact both media on all sides, and an amplifier circuit which together with the vibratory element forms an oscillator circuit in which the vibratory element is the frequency determining part. The vibratory element makes flexural vibrations at a resonance frequency. The apparatus further comprises a processing unit for measuring the momentary resonance frequency of the vibratory element and for deriving the level of the interface with respect to the vibratory element from said momentary frequency by means of the predetermined dependency of the resonance frequency on the depth of immersion of the vibratory element in the lower medium. The vibratory element is made as a plate-like element with a very small size with respect to the height of the reservoir.
    Type: Grant
    Filed: July 13, 1989
    Date of Patent: August 27, 1991
    Assignee: B.V. Enraf-Nonius Delft
    Inventor: Henk J. W. Reus
  • Patent number: 5033858
    Abstract: In a method and apparatus for detecting the presence of contaminants in a liquid stream which may also contain gas bubbles, the gas bubbles are detected by mechanically generating an alternating hydraulic pressure in the liquid stream, and monitoring the response of gas bubbles in the stream to the alternating hydraulic pressure.
    Type: Grant
    Filed: February 26, 1990
    Date of Patent: July 23, 1991
    Assignee: Westinghouse Electric Corp.
    Inventors: Michael Twerdochlib, Richard B. G. Chianese
  • Patent number: 5031451
    Abstract: A fluid level monitor for monitoring the level of fluid in a vessel comprises an inverted U-shaped propagation member which allows the propagation of stress waves therethrough. A first limb of the propagation member is immersed in the fluid in the vessel and a second limb is positioned outside the vessel. A transmitter transducer and a receiver transducer are acoustically coupled to the second limb of the propagation member. The transducer transmit stress wave pulses into the propagation member, the stress wave pulses produce a diffuse stress wave field in the propagation member which is damped by any fluid contacting the first limb of the propagation member. The transducer detects the stress waves propagating in the propagation member and produces an electrical signal corresponding to the level of the diffuse stress wave field. An analyzer measures the decay rate of the diffuse stress wave field which is indicative of the level of fluid in the vessel contacting the propagation member.
    Type: Grant
    Filed: December 29, 1989
    Date of Patent: July 16, 1991
    Assignee: Rolls-Royce plc
    Inventor: John R. Webster
  • Patent number: 5015995
    Abstract: A fluid level monitor for monitoring the fluid level in a tank comprises a first pair of transducers arranged in a vertically upper horizontal plane and a second pair of transducers arranged in a vertically lower horizontal plane. Pulse generators send electrical pulses to the transmitter transducers which transmit stress waves into the wall of the tank. The stress waves propagating peripherally are detected by the receiver transducers and processors analyze the amplitude of the detected stress waves to determine if the fluid is present or absent at the upper and lower horizontal planes. The pulse generators are arranged to send pulses out of phase so that stress waves propagating axially can be detected to determine alterations of the fluid level between the upper and lower horizontal planes. The processors may be arranged to operate alarms or to operate valves to control the fluid level in the tank.
    Type: Grant
    Filed: October 24, 1989
    Date of Patent: May 14, 1991
    Assignee: Stresswave Technology Limited
    Inventor: Trevor J. Holroyd
  • Patent number: 4964090
    Abstract: An ultrasonic sensor for fluid levels comprises a carrier having spaed-apart legs with registering openings adapted to receive a piezoelectric transmitter and a piezoelectric receiver in the openings. The piezoelectric members are separated by the spaced legs of a ground plane engaging plates of the piezoelectric members. Resilient members in the form of coiled conductors are entrained between a snap-on cover and the transducers so as to resiliently engage the piezoelectric members against the ground plane. The conductors are coupled by crimp connectors to the leads of a cable carried by an elongated channel portion of the carrier. The crimp conenctors are caried in recessed portions of the carrier, and the carrier is over-molded to encase the connectors and the cable. The cable is in turn coupled to an electronic control module positioned remotely from the fluid sump and connected to a warning device.
    Type: Grant
    Filed: July 19, 1989
    Date of Patent: October 16, 1990
    Assignee: TRW, Inc.
    Inventor: Michael C. McCarthy
  • Patent number: 4958518
    Abstract: A rod shaped or tubular housing for a sensor includes an interior space provided with upper and lower compensating openings and within which an ultrasound measured distance device. Below the ultrasound measured distance device, the interior is connected to the lower compensating opening through a narrow channel proceeding in an axial direction of the housing. The housing is formed of two half shells of plastic joined to one another whose wall parts engage into one another to form the narrow channel. The ultrasound transducers and the electrical leads are embedded into the half shells. A second ultrasound measured distance device which is in direct communication with the surrounding space may be provided above the interior space. The ultrasound transducer of the measured distance device is excited to transmit in a pulsed fashion.
    Type: Grant
    Filed: October 18, 1988
    Date of Patent: September 25, 1990
    Assignee: Siemens Aktiengesellschaft
    Inventors: Josef Duenstl, Siegfried Willner, Ralph Schroeppel
  • Patent number: 4954997
    Abstract: The sensor device for detecting the presence or absence of a liquid (2) at predetermined level (N) in a tank (1) comprises a transmitter transducer (51; 51'; 61), a receiver transducer (52, 52', 62), and electronic means (100) for processing the signals applied to the transmission transducer and delivered by the receiver transducer. In the vicinity of the predetermined level (N) of the tank (1), the device includes a detection plate (50; 50', 60) having at least one face (58) which comes into contact with the liquid (2) when the liquid reaches that level. The detection plate carries the transmitter transducer which is disposed for locally generating Lamb waves in the plate, and the plate also carries the receiver transducer which is disposed for detecting the presence or the absence of Lamb waves transmitted along the plate.
    Type: Grant
    Filed: March 3, 1989
    Date of Patent: September 4, 1990
    Assignee: Materiel et Auxiliare de Signalisation et de Controle pour l'Automation
    Inventors: Eugene J. Dieulesaint, Daniel R. Royer, Olivier R. Legras
  • Patent number: 4928525
    Abstract: A system for measuring the level of a fluid in a tank comprises a plurality of reflectors positioned in the tank with the reflectors being a known distance from one another and a first reflector being an unknown distance from the top of the tank and an apparatus for producing and outputting a sonic signal and for receiving echoes from the plurality of reflectors and a surface of the fluid in the tank. The apparatus produces electrical signals representative of the received echoes. The apparatus includes a processor responsive to the electrical signals for, (i) calculating the distance between the apparatus and the first reflector, (ii) calculating the distance between a last reflector and the fluid surface, and (iii) determining the total distance from the apparatus to the fluid surface based on the distances calculated in (i), (ii), and the distance between the first and last reflectors.
    Type: Grant
    Filed: March 2, 1989
    Date of Patent: May 29, 1990
    Inventors: Gary L. Aderholt, Michael A. Lenox
  • Patent number: 4912686
    Abstract: A sensor apparatus for detecting sludge in a tank e.g. an oil storage tank, wherein sonar tarnsmission and reception is effected by a transducer (29) whose acoustic center is coincident with the center of curvature of a liquid filled part spherical sonar dome part (15) of a housing (13) for the apparatus. The acoustic pressure waves consequently pass through the dome part of the housing in a direction normal to its surfaces thus minimizing velocity, amplitude and phase changes of the waves as they pass to and from the transducer, and avoiding blind spots in the area monitoried by sensor apparatus. Preferably, the apparatus further includes an arrangement (31, 33, 35, 37) within the housing for angularly moving the transducer (29) about two orthogonal axes which intersect at said center of curvature.
    Type: Grant
    Filed: December 13, 1988
    Date of Patent: March 27, 1990
    Assignee: GEC-Marconi Limited
    Inventor: William F. S. Craster
  • Patent number: 4909080
    Abstract: An ultrasonic level gauge that measures the level of a test surface inside a tank. A guiding pipe guides the ultrasonic wave transmitted by an ultrasonic transceiver to the test surface, and guides the ultrasonic wave reflected by the test surface back to the ultrasonic transceiver. An extended portion that extends the propagation distance of the ultrasonic wave guided by the guiding pipe may be provided on the basal portion of the guiding pipe. In this case, the ultrasonic transceiver is provided at the opening at the end of the extended portion. Also, a helical portion or a slanting portion may be provided in the guiding pipe to make the ultrasonic wave transmitted by the ultrasonic transceiver enter the test surface in a slanting direction.
    Type: Grant
    Filed: August 29, 1988
    Date of Patent: March 20, 1990
    Assignee: Toyoda Gosei Co., Ltd.
    Inventors: Mitsuhiro Kikuta, Toshinori Takahashi, Tatsuya Terayama, Kimiko Hasegawa, Chikahisa Hayashi
  • Patent number: 4901245
    Abstract: A non-intrusive acoustic sensor system for detecting and displaying the location of the level of a liquid in a tank uses a piezoelectric transceiver mounted to a bottom exterior location on the tank. The transceiver is an element of a driving and signal processing circuit which also includes a readout device for displaying liquid level location in selected terms. The system circuitry includes a microprocessor programmed to enable the velocity of sound in a liquid in the tank to be determined by the system at the site of use from a single distance measurement descriptive of the usage situation. The system automatically selects and uses the transceiver acoustic emission frequency which is best for the tank and liquid combination of interest at any time. The system, in a dual-transceiver configuration described, determines and uses speed of sound in the liquid as it in fact exists at any time.
    Type: Grant
    Filed: December 1, 1987
    Date of Patent: February 13, 1990
    Assignee: Moore Technologies, Inc.
    Inventors: Rodney S. Olson, Edward L. Christensen
  • Patent number: 4896536
    Abstract: A device for determining the filling level in a container including an oscillator with two rotational oscillation elements (10, 12) of the same resonance frequency which oscillate oppositely. The oscillation elements (10, 12) are arranged coaxially, have a common rotational axis, masses of the same size, and a common mass center. Both oscillation elements (10, 12) are fixed to a common membrane which serves as a retraction spring, through which a common drive of both oscillation elements (10, 12) is possible.
    Type: Grant
    Filed: October 28, 1988
    Date of Patent: January 30, 1990
    Assignee: Vega Grieshaber GmbH & Co.
    Inventor: Karl Benz
  • Patent number: 4890490
    Abstract: Ultrasonic Lamb waves are launched into a thin-section metal plate (10) which extends generally vertically above the contents of a vessel. As long as the lower end (18) of the plate (10) is above the liquid level, the Lamb waves are reflected at the lower boundary to give a full amplitude return signal. If however the liquid level rises into contact with the plate, mode conversion occurs at the interface between the plate and the liquid resulting in a reduced amplitude return signal. The arrangement may be used as a limit switch or may be calibrated to enable the liquid level to be related to the strength of the return signal. In a more elaborate arrangement, the plate (10) is of stepped configuration so as to present a series of shoulders (20A, 20B) at different heights. Each shoulder gives rise to a respective return signal and analysis of the return signals allows the liquid level to be determined.
    Type: Grant
    Filed: June 13, 1988
    Date of Patent: January 2, 1990
    Assignee: United Kingdom Atomic Energy Authority
    Inventor: David W. Telford
  • Patent number: 4853694
    Abstract: The present invention is an electronic liquid level monitoring apparatus for a in-ground storage tank. An ultrasonic transducer is disposed in a fill pipe head device which enables proper placement of the ultrasonic transducer in a fixed position relative to the fill pipe of the storage tank and provides a combination for a plurality of different fill pipe diameters. An electronic control measures the length of time from the transmission of the ultrasonic pulse to the receipt of the return echo and then calculates the distance from the ultrasonic transducer to the level of the liquid in the tank. The distance can permit automatic calculation of the amounts of liquid in the tank, using tank parameters stored in a memory as corrected for the speed of sound at the particular temperature measured via a temperature sensor. The apparatus preferably also calculates a volume variance.
    Type: Grant
    Filed: December 1, 1987
    Date of Patent: August 1, 1989
    Inventor: Jerry Tomecek
  • Patent number: 4847600
    Abstract: In fossil boilers and steam generator of fossil boilers and nuclear power plants, a son-air detector using ultrasonic transducers is employed with a glandless motor pump which may have a vertical top vent pipe to ascertain with fast response if the vent pipe has liquid or not. In the glandless motor pump, the pumped primary liquid per se is used for lubricating the bearings of the motor, whereby, if the lubricating liquid is absent, the motor operation should not be continued. For redundancy, a second transducer may be used, whereby when both the transducers are connected to simultaneously indicate absence of liquid in the vent pipe, suitable corrective action is initiated. A vent pipe filled with liquid will transmit ultrasonic bursts (provided by the transducer) through the liquid, so that the ultrasonic waves are reflected back. An empty vent pipe will not reflect the ultrasonic waves which would simply be dissipated.
    Type: Grant
    Filed: May 29, 1987
    Date of Patent: July 11, 1989
    Assignee: Westinghouse Electric Corp.
    Inventor: Donald R. Nixon
  • Patent number: 4841770
    Abstract: Apparatus (1) for measuring the amount of a substance (2) in a vessel which comprises a detector means comprising at least two electrodes (3) adopted to generate an electric signal in response to contact of the electrodes with the surface of the substance (2), a first reference point (6) on the detector means which point is a fixed distance from the ends of the electrodes (3) said reference point being provided on a material suitable for reflecting waves from a wave transmitting-receiving device (8) e.g. a sonar device, preferably located in a fixed position above the first reference point for measuring the distance from the first reference point (6) to a second reference point (70) at the wave transmitting-receiving device (8) whereby the amount of the substance (2) in the vessel can be determined by computation, e.g.
    Type: Grant
    Filed: October 19, 1987
    Date of Patent: June 27, 1989
    Assignee: Parke-Davis & Co. Ltd.
    Inventor: Robert L. Davies
  • Patent number: 4841256
    Abstract: A structural member having a piezoelectric transmitter film and a piezoelectric receiver film adhered thereto. The transmitter film produces a vibration upon activation by a voltage controlled oscillator which forms part of a phase-lock loop circuit. The vibrations of the structural member generate electric signals on the receiver film, which feed into a phase comparator. The other input of the phase comparator is the output signal of the voltage controlled oscillator. The phase comparator will output a dc signal proportional to the difference in phase between the two signals. When the structural member becomes damped, the phase comparator will go into saturation, thereby producing a voltage which can activate an alarm signal or other device.
    Type: Grant
    Filed: October 20, 1987
    Date of Patent: June 20, 1989
    Assignee: Pennwalt Corporation
    Inventor: Raymond F. Gastgeb
  • Patent number: 4787240
    Abstract: A pipe section through which a liquid passes includes a transmitting and receiving transducer diametrically opposed on the surface of the pipe and arranged to project acoustic energy through the interior of the pipe whereby the output signal from the receiving transducer changes in the presence of a liquid in the acoustic path between the transducers. V-shaped grooves or other surface modifications are made to the surface of the pipe circumferentially between the transducers so as to redirect wall-borne acoustic energy to a more axial direction thus preventing its reception at the receiving transducer.
    Type: Grant
    Filed: August 31, 1987
    Date of Patent: November 29, 1988
    Assignee: Westinghouse Electric Corp.
    Inventor: James L. McShane
  • Patent number: 4785663
    Abstract: A level control instrument for controlling and/or indicating the filling level for liquid, powder, granular, especially light-weight bulk material in a container. The level is determined by a single rod shaped vibrator that is actuated by a vibration exciting and measuring system. The vibrator is a rod adapted to act as a bending vibrator which is dampened by bulk or liquid material. The dampening is controlled by the vibration exciting and measuring system. In order to prevent the vibrating energy from being transmitted to the container wall, the vibrating rod has two supports spaced from each other with each located at a nodal point on the rod. One free end of the rod extends into the material containing space of the container. If the two supports are at or near to the points where the vibration nodes appear when the rod is excited to bending vibration it is practically impossible for the vibration energy to be transferred to the container wall.
    Type: Grant
    Filed: June 3, 1987
    Date of Patent: November 22, 1988
    Inventor: Eberhard F. Hermann
  • Patent number: 4785664
    Abstract: An improved ultrasonic system for detecting the level of a material that has a surface, for example a liquid level inside of a tank, which improves the ability to detect levels particularly when the tank is nearly full. A transmitted ultrasonic signal from a transducer is reflected against the material in the tank, and when received back at the transducer, an output pulse is provided from the transducer. The distance or level is determined by determining the time between the transmission and the reflected signal. A comparator compares the signal from the transducer with a reference and provides an output when a pulse of greater magnitude than the reference is received.
    Type: Grant
    Filed: April 28, 1986
    Date of Patent: November 22, 1988
    Assignee: Kay-Ray, Inc.
    Inventor: Stephen R. Reebs
  • Patent number: 4750117
    Abstract: Apparatus for determining or measuring the depth of precipitation accumulating on the surface of a pathway, such as an airport runway or the like. The apparatus includes a sensor having electrical transducer means for emitting and sensing ultrasonic energy and having a body of material adapted to be embedded in the pathway with the top surface of the body being substantially flush therewith and exposed to the precipitation, the transducer means being physically coupled to the body. A circuit causes the transducer means to emit pulses of ultrasonic energy which are reflected as a plurality of reflections from the top surface of the body and from the upper surface of an accumulation of precipitation on the top surface of the body and are respectively returned to the transducer means which in response to the reflected pulses produces corresponding electrical signals.
    Type: Grant
    Filed: December 13, 1984
    Date of Patent: June 7, 1988
    Assignee: Surface Systems, Inc.
    Inventor: Robert O. Gregory
  • Patent number: 4740726
    Abstract: A vibrator-type level sensor having a detecting pipe (20) in which an inner vibration member (22) with piezo-electric devices (8a) (8b) (8c) is mounted, the detecting pipe (20) and the inner vibration member (22) constituting a folded cantilever.
    Type: Grant
    Filed: July 21, 1986
    Date of Patent: April 26, 1988
    Assignee: Nohken Inc.
    Inventor: Takayuki Umezawa
  • Patent number: 4735191
    Abstract: A device primarily for attachment to the spout of a teakettle for generating a musical signal in response to the vapor pressure of boiling water. A diaphragm distorts in response to the pressure and closes an electrical switch which applies battery voltage to a circuit in which a representation of a pre-selected tune is stored. The tune is applied to a piezoelectric speaker within a resonating housing to audibly signal the user that the water in the teakettle is boiling.
    Type: Grant
    Filed: February 5, 1987
    Date of Patent: April 5, 1988
    Assignee: Musikettle, Inc.
    Inventors: Pierre G. Boursse, Bill Grau, Anton Gattiher
  • Patent number: 4703652
    Abstract: Piezoelectric type liquid level sensor for detecting whether the level of various liquids such as oil of an internal combustion engine, a generator or the like is a predetermined value or higher or not, and method of making the sensor. The sensor is arranged to eliminate the influence of the weight of the lead wires on the vibration element and to facilitate its assembly. The sensor may be provided with a damper member for increasing the sensitivity.
    Type: Grant
    Filed: December 2, 1985
    Date of Patent: November 3, 1987
    Assignee: NGK Spark Plug Co., Ltd.
    Inventors: Akio Itoh, Kazunori Sumi, Sigeo Saitoh, Hideo Sobue
  • Patent number: 4679430
    Abstract: A sensor for detecting an interface of a liquid in a container comprises a transmitter and a receiver of ultrasonic waves, each situated outside the container, and coupled to the wall of the container by a strip waveguide. The transmitter is arranged to cause surface acoustic waves to propagate through a portion of the wall, and the receiver is arranged to detect waves derived from the transmitter. When the liquid is adjacent to the portion of the wall, mode conversion of the surface acoustic waves in the wall of the vessel into compression waves in the liquid causes a change in the energy of waves reaching the receiver.
    Type: Grant
    Filed: March 26, 1984
    Date of Patent: July 14, 1987
    Assignee: United Kingdom Atomic Energy Authority
    Inventors: Colin B. Scott-Kestin, Roger B. Pike, Roger D. Watkins, Arthur B. Gillespie, Michael O. Deighton
  • Patent number: 4679160
    Abstract: Apparatus for determining the depth of precipitation accumulating on the surface of a pathway, such as an airport runway or the like, includes a sensor having electrical transducer means for emitting and sensing ultrasonic energy and having a body of material adapted to be embedded in the pathway with the top surface of the body being substantially flush therewith and exposed to the precipitation, the transducer means being physically coupled to the body. A circuit causes the transducer means to emit pulses of ultrasonic energy, which are reflected as first and second reflections from the top surface of the body and from the upper surface of an accumulation of precipitation on the top surface of the body and are respectively returned to the transducer which, in response to the reflected pulses, produces corresponding first and second electrical signals.
    Type: Grant
    Filed: December 13, 1984
    Date of Patent: July 7, 1987
    Assignee: Surface Systems, Inc.
    Inventor: Miles B. Whitener
  • Patent number: 4675660
    Abstract: Procedure to measure the level (14) of a liquid (13) by means of elastic waves, such liquid (13) being contained within an axially moving tube (11) and cooperating with a filler tube (12), the filler tube (12) being used as an element in the transmission of elastic waves to the liquid (13), such elastic waves being picked up (16) outside the axially moving tube (11).Device (10) to carry out the above procedure, which device (10) cooperates with a filler tube (12) and comprises:at least one transducer (15) to transmit energization of the vibration of the filler tube (12), andat least one receiver transducer (16) located outside the axially moving tube (11).
    Type: Grant
    Filed: January 9, 1986
    Date of Patent: June 23, 1987
    Assignee: TETRA DEV-CO Consorzio di Studio e Ricerca Industriale
    Inventor: Antonio Boscolo
  • Patent number: 4673927
    Abstract: An apparatus for detecting and controlling the presence of a gaseous fluid in relation to a predetermined level of liquid in a vessel, being of the ultrasonic type and comprising a pair of piezoelectric transducers, namely a transmitter and a receiver, capable of being disposed on opposite walls of the vessel. An oscillator provides an electric ultrasonic frequency signal to the transmitter transducer and a comparator compares the electric signal supplied by the receiver transducer with a reference signal for triggering an alarm signal when the disparity between the signals being compared exceeds a predetermined value.The apparatus moreover comprises processing means which periodically interrupt the electric signal sent to the transmitter transducer and which check the presence of an alarm at the output of the above mentioned comparator.
    Type: Grant
    Filed: October 25, 1985
    Date of Patent: June 16, 1987
    Assignee: Hospal A.G.
    Inventors: Domenico Cianciavicchia, Stefano Franceschini
  • Patent number: 4668945
    Abstract: A device for detecting the presence of a gaseous fluid in relation to a predetermined level of liquid in an elastically deformable vessel comprises a U-shaped body capable of accommodating within it a portion of the vessel at a predetermined liquid level. A pair of piezoelectric transducers in the body, used as transmitter and receiver, is fixed face-to-face on opposite arms of the U-shaped body. The device moreover comprises a cover capable of confining the portion of the vessel inside the U-shaped body, and an elastic device disposed between the cover and the U-shaped body and capable of producing an elastic deformation of the vessel and causing the contact surfaces of transducers to contact intimately the said portion of the vessel without entrapment of air.
    Type: Grant
    Filed: October 25, 1985
    Date of Patent: May 26, 1987
    Assignee: Hospal A.G.
    Inventors: Mauro Aldrovandi, Mauro Facchini
  • Patent number: 4630245
    Abstract: A transmitting transducer is mounted on the outside wall of a vessel and supplies bursts of ultrasonic energy. If liquid is present, the energy is coupled to the other side of the vessel. Otherwise, the energy is attenuated. A receiving transducer (which may be the same as the transmitting transducer) is positioned to receive the ultrasonic energy if liquid is present. It is gated to be active only when such energy should arrive in the presence of liquid. The receiving transducer therefore generates an electrical signal indicating presence or absence of liquid in the vessel at the level at which the transducers are mounted.
    Type: Grant
    Filed: July 15, 1983
    Date of Patent: December 16, 1986
    Assignee: Introtek Corporation
    Inventor: Naim Dam
  • Patent number: 4610164
    Abstract: An ultrasonic wave transmitter and an ultrasonic wave receiver are disposed in a tank in any positional relation to each other so long as the wave transmission and wave reception surface do not face each other to check whether the liquid level in the tank is above a predetermined level. When both the wave transmitter and wave receiver are submerged in the liquid in the tank, a wave radiated from the wave transmitter can be received by the wave receiver because of the facts that the directivity angle of the wave from the transmitter is large in the liquid and the wave propagates through the liquid without attenuation. When the liquid level decreases and becomes lower than either of the wave transmitters or wave receiver that is at an upper level, a wave from the transmitter can no longer be received by the receiver. This principle is utilized for the liquid level detection.
    Type: Grant
    Filed: June 7, 1985
    Date of Patent: September 9, 1986
    Assignee: NGK Spark Plug Co., Ltd.
    Inventors: Hideo Sobue, Toshiharu Ito
  • Patent number: 4594584
    Abstract: The device for determining and/or monitoring a predetermined filling level in a container has two oscillatory rods secured with spacing adjacent one another on a diaphragm the edge of which is connected to a screw-in part. By means of the screw-in part the device is so secured in a screw-threaded aperture of the container wall at the height of the filling level to be detected that the oscillatory rods project into the container. At the side of the diaphragm remote from the oscillatory rods a bridging member is held spaced from the diaphragm by flexurally elastic rod-shaped supports. Each of the rod shaped supports is rigidly connected at one end to an oscillatory rod. Between the bridging member and the diaphragm there is held, with preloading of the diaphragm, a transducer column comprising in a stack a piezoelectric excitation transducer and a piezoelectric reception transducer.
    Type: Grant
    Filed: October 1, 1984
    Date of Patent: June 10, 1986
    Assignee: Endress u. Hauser GmbH u. Co.
    Inventors: Helmut Pfeiffer, Volker Dreyer, Martin Pfandler
  • Patent number: 4545245
    Abstract: A liquid level sensor includes a pair of sonic waveguides separated from and parallel to one another. The waveguide pair together define axially separated pairs of lens surfaces so that sonic pulses are coupled therebetween in a time phase relationship when liquid covers those lens pairs below the liquid level, cross coupling of those lens pairs above the liquid level thereby being prevented. Since the axial separation dimension of the lens pairs is known as well as the vessel geometry and location of the waveguide pair in the vessel, counting the pulses returned by virtue of such cross coupling of those lens pairs below the liquid level will establish accurate level detection by standard algorithmic techniques.
    Type: Grant
    Filed: November 9, 1983
    Date of Patent: October 8, 1985
    Assignee: Simmonds Precision Products, Inc.
    Inventor: David L. Sharp
  • Patent number: 4540981
    Abstract: Method and apparatus for detecting the presence of liquid in a container includes an elongate rod (or other vibratory element) which extends into the container to contact liquid when a certain amount of liquid is present, a piezo-electric element coupled to the rod on the exterior of the container to cause the rod to vibrate in response to electrical signals and to produce electrical signals indicative of the amplitude of vibration of the rod, and circuitry for producing a utilization signal when the electrical signals produced by the piezo-electric element indicate that the amplitude and duration of vibrations of the rod are below some threshold level. Such vibrations fall below the threshold level when the rod contacts liquid in the tank and so production of the utilization signal is an indication that liquid in the container has reached a certain level.
    Type: Grant
    Filed: October 29, 1981
    Date of Patent: September 10, 1985
    Assignee: Edo Western Corporation
    Inventors: Robert A. Lapetina, Howard P. Jones
  • Patent number: 4535628
    Abstract: An apparatus for measuring acoustic transmission characteristics of at least one medium to be measured in which at least one elongated hollow chamber is immersed. The chamber is closed at its bottom end and is filled with an acoustic connecting liquid, and at least two separate movable transducers are immersed in the connecting liquid within the chamber in spaced relation to the wall thereof, the chamber having a cross-sectional shape such that a directional acoustic path between opposite emitter and collector transducers passes through the medium to be measured, the medium being out of direct contact with the transducers.
    Type: Grant
    Filed: January 21, 1983
    Date of Patent: August 20, 1985
    Inventor: Bjorn R. Hope