Abstract: The present application discloses a magnetostrictive linear displacement detector with an axial coil torsional strain transducer. The displacement detector includes a magnetostrictive wire, a return wire and a magnet disposed for displacement along the magnetostrictive wire. A torsional strain sensor at the head end generates an electrical indication of the torsional strain within the magnetostrictive wire induced by passage of an electrical excitation by the position of the magnet. The torsional strain sensor includes two serially connected coils wound in opposite directions. The total length is short compared with the rate of electrical propagation within the magnetostrictive wire and long compared with the rate of torsional strain propagation within the magnetostrictive wire. The induced current within the two coils from electrical excitation of the magnetostrictive wire substantially cancel out because generally the whole sensor is excited simultaneously.

Abstract: A technique and sensor is provided for directly measuring the thickness of ayers of immiscible liquids of differing densities and other materials contained in a tank or other container, preferably by reflection of ultrasonic energy. A preferred form of float comprises a container filled with material sampled from the tank and includes a reflector of ultrasonic energy of greater density, whereby the reflector is accurately positioned at an interface between two immiscible liquids of differing densities. The float is restrained close to the axis of energy radiation of the ultrasonic transducer by either a tube, forming a housing or a flexible cord. If a tube is employed, a slit in a lateral side thereof allows the tube to act as a baffle and reduce the effects of fluid motion within the tank on the measurement being made.

Abstract: A transducer assembly for an ultrasonic liquid level measuring device utilizing a piezoelectric crystal for generating ultrasonic pulses to be transmitted through a volume of liquid. The assembly includes an enclosure for the piezoelectric crystal assembly, that defines an interior space and a sealed opening for a cable. The enclosure is provided with a metallic layer that shields the entire interior space from electromagnetic interference. The assembly also includes a crystal housing assembly and a terminal block all located within the sealed enclosure.

Abstract: The device comprises at least two oscillation rods that are mounted at a distance from each other on a membrane, the edge of which are connected with a screw insert. A clamping screw is connected with the membrane on the side opposing the oscillation rods in such a rigid manner that the clamping screw and the membrane assume a position to each other in which their symmetry axes coincide. The clamping screw is surrounded by a stack of annular piezoelectric elements, electrode rings as well as insulating rings. This stack forms the excitation and reception transformer of the device. The stack-shaped excitation and reception transformer is clamped and mounted between the membrane and a hexagonal nut. The stack braces itself on a shoulder that encompasses the membrane within a distance by the metal ring that closes the stack. The clamping force is chosen such that the membrane is simultaneously prestressed in a concave manner.

Abstract: In a position detection probe having a magnetostrictive wire stretched between a head and a reflective foot end termination, and a magnet displaceable along the probe and using the sonic pulse propagation time from the magnet to the foot end termination as a position detection parameter, compensation for thermal expansion and thermal change of propagation velocity is made by measuring the wire resistance and calculating a compensation from the resistance. The probe is excited by an electrical pulse having a known current. The voltage across the wire is measured at a time when the current has stabilized to a precise value, and resistance is determined from the current and voltage.

Abstract: Ultrasonic fuel gauging apparatus for a fuel tank having a plurality of ultrasonic fuel level sensors for sensing fuel levels at respective predetermined locations in a tank based on echo ranging; a memory means for storing sensor data; and a state device for interrogating each of the sensors by controlling the application of transmit pulses to each of the sensors and for receiving output signals corresponding to return echoes, the state device operating in response to a sequential state counter.

Abstract: The invention discloses a level measuring device which can be made up from components. It comprises a sonic or ultrasonic transducer which is arranged in a first housing and forms a self-contained functional unit; the electrical circuit arranged in a further separate housing forms a second functional unit. The functional units are so constructed that they can be assembled from the various components to a complete level measuring device in accordance with the required use conditions by arrangement of a steel plate above the sonic or ultrasonic transducer, or by potting with a commercially usual potting composition, or the selection of two different similar housings for receiving the sonic or ultrasonic transducer or the arrangement of selectively different but dimensionally identical sonic or ultrasonic transducers, and the selective mounting by means of a loose flange on a container, or by means of a suspension bracket in the interior thereof or above a drain.

Abstract: An ultrasonic liquid level gauging sensor has a transducer at the lower end of a tube that is filled with liquid to the same height as liquid outside the tube. The sensor has an axial rod extending along the tube and supporting several calibration reflectors. The rod enables the sensor to be used at high tilt angles.

Abstract: The apparatus of the invention is a water level probe comprised of a probe body, a sleeve having openings permitting fluid flow and encasing part of a magnetostrictive sensor, and an external housing encasing electronic circuitry for processing and transmitting the electric signal generated by the magnetostrictive sensor and sealing the circuitry from fluids. The sensor comprises a float slidably mounted on a rod, the float designed to float in water but sink in a petroleum product, thereby ensuring that it will float at the interface between the water and the product. The water level probe is used in the method of the invention to measure the depth of the water in a vessel storing hydrocarbon product at predetermined time intervals. The longitudinal angle of inclination of the vessel with respect of the horizon having previously been determined, the volume of water in the vessel is calculated from the depth measurements.

Abstract: An ultrasonic detector of the type for determining the level of a liquid within a tank or the magnitude of the flow of liquid within a conduit. The detector includes a transducer that generates bursts of ultrasonic energy and receives echoes of the energy bursts. The frequency at which the transducer transmits energy bursts is automatically adjusted to substantially match the ringdown frequency of the transducer. The detector distinguishes between true echo signals and spurious echo signals by determining whether the frequency of the echo signals generated by the transducer substantially matches the frequency at which the corresponding energy bursts were transmitted.

Abstract: To determine the depth of a body of water, ultrasonic pulses are transmitted from a point above the water at a known distance. Reflections from the water are received and the time of each of the leading edge of the reflections and the trailing edge are recorded as well as the amplitude. This information is used to sort the reflections and the most significant reflections are used to calculate the level of the water.

Abstract: In one aspect of the present invention, an apparatus for measuring the height of liquid contained in a storage tank is disclosed. A tube is disposed inside the tank. A float is disposed inside the tube and is buoyed on the surface of the liquid. An ultrasonic transducer is disposed inside the tube. The ultrasonic transducer emits ultrasonic pulses toward the float, receives the reflected ultrasonic pulses, and responsively produces an echo signal. The float has a top portion and a bottom portion separated by a cylindrical portion. The bottom portion including an spherical surface which receives the ultrasonic pulses. The spherical surface has a predetermined radius which is a function of the inside diameter of the tube, the height of the cylindrical portion of the float and the outside diameter of the cylindrical portion of the float. A temperature sensor monitors the temperature of the liquid and produces a thermometric signal in response to the liquid temperature.

Abstract: The quantity of fuel in a fuel tank 1 is measured by determining the displacement of a membrane 19 and pressure values from a sensor 13. The displacement values of the membrane are representative of volume changes in a gas chamber in the tank 1 while the pressure values in the sensor 13 are representative of the pressure of the gas chamber. With these values, the fuel content in the gas tank can be determined from the general equation of state of an ideal gas. In order to displace the membrane 19, an electric motor 20 drives a step down transmission 25 which in turn drives a spindle mechanism 22 which is coupled to the membrane 19.

Abstract: A low cost phased array sonic transducer is described in which an array of transducer elements separated by spacers are held within a frame which applies a compressive force transverse the length of the elements.

Abstract: An ultrasonic liquid-level sensing system has a sensor with a number of reflectors mounted one above the other along the length of a tube that extends upwardly from a transducer and is filled with liquid to the same height as outside the tube. Liquid height is calculated from the difference between the arrival times of the pulses reflected from the two uppermost submerged reflectors and the difference between the arrival times of pulses reflected from the surface of the liquid and the uppermost submerged reflector.

Abstract: A volume sensing system includes electronic circuitry which is electrically connected to an ultrasonic transducer. The transducer is affixed by means of an adaptor to the base of a container having a known configuration. The container holds a liquid and a gas so that a liquid-gas boundary is formed within the container. The transducer generates ultrasonic pulses which propagate through the liquid, are reflected at the liquid-gas boundary, and are received again by the transducer. The received return pulse is converted into an electrical signal which is analyzed by the electronic circuitry to determine the level of the liquid within the container. The level of the liquid within the container is then employed to determine the volume of the liquid within the container in accordance with the configuration of the container. In a preferred embodiment, the adaptor includes an indicator which may be used to identify the configuration of the container.

Abstract: An ultrasonic liquid level sensor has a transducer mounted at the lower end of an aluminum tube that projects upwardly in a liquid tank so that the tube is filled with liquid to the same height as that outside the tube. Internally, the tube has a layer of an acoustically-absorbing plastics to damp the transmission of ultrasonic vibration from the wall of the tube into liquid within the tube.

Abstract: A distance measuring device for measuring the fill level in industrial tanks, which includes electronic transmitting- and receiving elements for short wave electromagnetic waves, such as microwaves, and a cylindrical waveguide which extends through a separating wall and inside of which is a waveguide window separating the two spaces and made of a material, such as quartz glass, which is transmissive with respect to electromagnetic waves. The waveguide and the waveguide window (3) have conically-shaped sections (5) to provide axial support. To protect the waveguide window against destruction due to thermal expansions and pressure fluctuations, the conical section (5) of the waveguide window (3) is in a correspondingly formed conical socket (8). The socket is mounted with play in a cylindrical bore (9) of the waveguide window (3) and is supported by a shoulder (10) of the waveguide in the axial direction.

Abstract: A liquid level sensor has a liquid sensing element carried on the end of a curved probe which is inserted into a liquid-holding chamber. The probe can be rotated to properly locate the sensor within the chamber. A threaded nut locks the curved probe in position to maintain the sensor in the proper position.

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.

Abstract: A method for measuring the temperature-compensated change in the height of a surface of a liquid. The method positions an acoustic signal transducer for emitting and receiving acoustic signals below the surface of the liquid, positions a quasi-static reference device with a fiducial such that the fiducial lies within a predetermined range below the surface of the liquid, and positions one or more fiducials below the surface of the liquid to establish points separated by known distances. The transducer emits acoustic signals, and receives their reflections. The travel times of the reflections from the liquid surface and the fiducials are used to calculate changes in travel times during the measurement period, to estimate the speed of sound in the liquid, to correct for temperature-induced changes in the travel times, and to obtain a temperature-compensated change in travel time to the liquid surface.

Abstract: This instrument contains a transducer and a sensor that are mounted on the exterior surface of a liquid container or tank. The transducer is tuned by electronic signals to the mechanical resonant frequency of the liquid container or tank. The sensor converts the mechanical vibrations into dynamic electrical signals using electronic components. A phase detector and feedback circuitry force the transducer to track the resonant frequency of the tank as liquid is removed from the tank. The signal output of the feedback control circuitry is converted to display the amount of liquid remaining in the tank. The resonant frequency of the liquid container is a measure of the total mass of the container. This includes the tare weight of the container plus the weight of the liquid in the tank. The tare weight of the tank is a constant. The stiffness of the tank can be considered a constant. The dampening coefficient changes do not adversely effect the accuracy requirements of the instrument.

Abstract: A position detection probe having a magnetostrictive wire stretched between a head and a reflective foot end termination, and a magnet movable along the probe uses the sonic pulse propagation time from the magnet to the head as one parameter and the time from the magnet to the foot and reflected back to the head as another parameter for determining the magnet position. The sum of the propagation times is a constant which is used as a reference value. Upon receipt of the first two pulses the propagation times are summed and compared to the reference value, and the data is accepted if the sum is within a prescribed window around the reference value. When noise occurs, it creates a false measure of propagation time so that the sum of the propagation times is no longer equal to the reference value and the data is rejected.

Abstract: A magnetostrictive liquid level transducer equipped with a number of temperature sensitive resistors is supplied with low level power from a remote station and charges a capacitor to store power for interrogation of the level transducer. The transducer is interrogated periodically for level measurements and the capacitor is recharged between interrogations. During the recharging periods, temperature measurements are made. Thus the level and temperature related data is measured and transmitted alternately. Each measurement results in a pair of pulses having a spacing corresponding to the measured value. The transmission message comprises a plurality of frames or time periods. The first frame is blank and is used for synchronizing the receiving device with the message frames. The subsequent frames have the level and temperature related data interleaved in the message and are easily sorted by the receiving device at the remote station. The data pulses are sent on the power transmission conductors.

Abstract: A density measuring device having a float with a marker provided therein that is connected by a pair of springs to each of the two supports which are on opposite sides of the float along a guide. A sonic waveguide arrangement is provided extending along this guide past at least one of the supports which can measure the relative positions of the float to thereby determine the effective buoyant force on the float and so the density of the fluid in which the float is submerged. Use of a further float permits determining fluid levels.

Abstract: An acoustic fuel (or other liquid, powder or solid) sensor is disclosed. The sensor measures the volume of fuel in a container of known size. The air within the container is excited by an acoustic transducer. The transducer is driven by a frequency scanning source, and the frequency response of the air cavity within the container is monitored. This frequency response is then processed to determine the volume of air in the container, and the fuel volume is determined to be the total container volume less the air volume. In one embodiment, a tube connects the transducer through an orifice to the air volume, and the frequency response is observed to determine the resonant frequency of the air cavity within the container. The volume of the air cavity is then determined from the resonant frequency. The volume of the fuel is then determined from the tank volume minus the volume of the air cavity.

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.

Abstract: An apparatus for measuring liquid levels and leak rates in a storage tank, using an acoustic transducer and a quasi-static reference device that positions an acoustic target within a predetermined distance range below the surface of the liquid.

Abstract: In a level measuring device for containers filled with fluid, preferably tanks in tank installations, the fill level height h is determined from the transit time of ultrasound pulses which are emitted by first sound pulse transmitters along a main measuring path extending from the bottom region of the tank to the fluid surface and are reflected from the fluid surface to first sound pulse receivers. Temperature sensors are provided for finding the temperature distribution throughout the fill level height h. Processing the measurements provides a mean temperature TM in the fluid volume. In addition to the main measuring path there is a reference path in the fluid volume, with second sound pulse transmitters and receivers and a reference temperature sensor for measuring a reference temperature T.sub.Ref. The reference path makes it possible to find the sound velocity v*(T.sub.Ref) in the fluid volume at the reference temperature T.sub.

Abstract: A flexural acoustic wave sensing method and efficient, simple, miniature and economical ultrasonic devices using thin rods are presented. The diameter of the thin rod is less than one acoustic wavelength. The lowest order flexural acoustic wave, F.sub.11 mode, propagating along such thin rods is used. The thin rod materials can be metals, glasses, ceramics, polymers and single crystals. Any external disturbance which can alter the propagation characteristics of F.sub.11 mode may be monitored by recording such variation. Fiber acoustic interferometers, which are built by jointing two thin rods, can offer high sensitivity. These devices are primarily used for sensors.

Abstract: A toner residual amount detecting mechanism comprises a stirring device and a photosensor. The photosensor has a protrusion, and rotates together with a stirring shaft while the protrusion contacts with a pin planted on the stirring shaft. The stirring device rotates by its gravity when it reaches a top dead point thereof. The stirring device also includes a magnetic rotor attracted by a permanent magnet in a sensor lever to thereby turn the sensor lever about the fulcrum of the sensor lever to a predetermined position. The sensor lever is stopped by a stopper when the stirring device reaches the bottom dead point thereof. The photosensor cannot detect light when the sensor lever is positioned at the bottom dead point since the light is intercepted by the sensor lever but can detect the light when the sensor lever reaches the predetermined position. The mechanism can inform an operator of a toner supply time since the photosensor operates depending on the resistance of toner against the stirring device.

Abstract: A two-wire ultrasonic transmitter senses level of a material and controls current of power supplied thereto to a magnitude representing sensed level The transmitter comprises a transducer mounted in proximity to a material, the level of which is being sensed. A power supply circuit receives power for operating the instrument. A drive circuit is connected to the transducer and the power supply circuit and periodically energizes the transducer to transmit an energy pulse to be reflected off of a surface of the sensed material. An amplifier circuit is connected to the transducer and develops an analog signal having a magnitude corresponding to reflected energy received by the transducer.

Abstract: A mounting structure is provided which is particularly adapted for holding a level sensor in place at an opening on vessels containing pressure above or below the ambient pressure. First and second fitting members are provided which are installed on the vessel at the opening provided thereon. The level sensor is releasably attached to the second fitting member positioned on the exterior of the vessel so it is in communication with the interior of the vessel. The first and second fitting members are mechanically locked together so that the vessel wall is held captive between the fitting members. The mounting structure provides a positive mechanical lock between the vessel and the level sensor ensuring that the level sensor will not be blown out of, or sucked into, the vessel even if the fluid tight seal between the mounting structures fails.

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.

Abstract: A liquid level and temperature sensing device for monitoring and measuring the level of liquid stored within a tank or reservoir comprising control circuitry to generate and transmit digital level interrogation pulses and a transducer to receive sonic level return signals corresponding to the digital level interrogation pulses and generate corresponding digital level signals and logic circuitry to measure the time lapse between corresponding digital level interrogation pulses and the corresponding digital level signals and a lower sensing probe including an inner conductor coupled to the control circuity to receive the digital level interrogation pulses and a float to float on the liquid within the tank or reservoir including a magnet movable tube to interact with the electromagnetic field generated in the inner conductor by the digital level interrogation pulses to generate the corresponding sonic level return pulses transmitted to the transducer to generate the corresponding digital level signal whereby the

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.

Abstract: An apparatus and method for measuring the level of a liquid within a storage tank, including a target for being buoyantly supported near the surface of the liquid and an acoustic sensor for measuring the distance between a tank reference point and the target. The motion of the target induced by any change in level of the liquid is restrained along a known path so that the target distance is representative of the level of the liquid within the tank.

Abstract: The length of a column of a gaseous or liquid substance or of a solid bar is determined by generating a standing wave of known frequency, wavelength and/or wave velocity in the column or in the bar. The wave frequency is varied until at least two consecutive maxima (antinodes), two consecutive minima (nodes) or a minimum following a maximum of the amplitude of the standing wave have been detected. The length of the column of medium at known frequency and wave velocity of the standing wave generated in that column is computed from the equationL=c/[2(f.sub.n -f.sub.n-1)] (1),where L is the length of the column of medium, c is the wave velocity, f.sub.n is the frequency of the nth maximum and f.sub.n-1 the frequency of the (n-1)th maximum. Apparatus for implementing the method comprises a loudspeaker 1 mounted in a resonance chamber 2 with a tubular acoustic exit aperture 3.

Abstract: A liquid level sensor system for a tank includes a stillwell having a transducer assembly positioned in the bottom of the stillwell. A guide conduit surrounds a flexible plastic coated wire bus which extends through a sidewall of the tank and which connects the transducer assembly to an indicator assembly located outside the tank. The conduit includes an end cap which secures the wire bus within the conduit. Installation and removal of the transducer assembly and wire bus is accomplished at a location outside the tank by removing the end cap and pulling or pushing the transducer assembly through the conduit by means of the wire bus.

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.

Abstract: A non-contact type ultrasonic distance measuring device that includes a micro processor for controlling operation of a transducer that functions as both a sonic transmitter and receiver. Micro processor programming provides a control scheme whereby an operator can program different modes of operation into the instrument by depressing buttons arranged on a rear display panel of the instrument. Mode programming is accomplished in a manner similar to setting a digital watch, with the modes displayed in a display window. The mode programming and component operation provide a gate scheme where gate control is provided through application of gain control through three (3) amplifiers, one of which is a fourth order bandpass filter that is operated by the micro processor to provide a controlled increase in gain or "Q" as the elapsed time from a transmission becomes greater.

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.

Abstract: A process for detecting a phase boundary surface between layers of fluids which are not intermixable with one another includes the steps of penetrating at least one of the fluids with sound waves to strike a reflector, receiving the reflected sound waves, comparing the transmitted sound waves to the reflected and received sound waves, using the comparison to determine the acoustic propagation impedance, and using the results to determine the position of the phase boundary layer.

Abstract: A magnetic sight gage sensor comprises a sensor for determining the liquid level in a process vessel utilizing a magnetic float on the interior of a tube. The tube is connected at different levels to a process vessel and contains a liquid that is maintained at the same level as the liquid inside the process vessel. A magnetostrictive displacement transducer is coupled to the tube or sight glass on the exterior of such glass, so it is out of the process fluid. The transducer provides signals indicating the position of the float relative to a reference position on the transducer. The tube or sight glass is made of a non-magnetic material in order to allow transmission of the magnetic field from the float to the transducer.

Abstract: A device for gauging the level of a fluid in a container with a microwave signal is described. The device comprises a vertical tube (1) mounted in the container, and a transmitter and a receiver and an electronic unit for determining the level based on the reflex position of the microwave signal. The device is characterized particularly by a calibration device in the form of a polarization means (6, 7) for polarizing the microwave signal in two polarization planes separated from each other and at least one reflecting reactance (10) in the tube (1) arranged to give a substantially stronger reflex of the microwave signal in the first polarization plane than in the second.

Abstract: An ultrasonic level detector includes a transducer for generating and receiving bursts of sonic energy at a surface to locate the position of the surface. In response to receiving a burst of energy reflected from the surface, the transducer generates an electrical signal, which is then supplied to a variable gain amplifier. After amplification, the electrical signal is supplied to a comparator and a peak detector. The comparator generates a timing signal upon the electrical signal exceeding a threshold. A window generator circuit generates a receive window that controls whether the electrical signal is supplied to the comparator and the magnitude of the threshold on the comparator. The peak detector determines the maximum amplitude of the electrical signal, which may be used to vary the amplifier gain and the number of pulses included in an excitation signal which drives the transducer. Upon receipt of the timing signal, a microprocessor determines the distance between the transducer and the detected surface.

Abstract: Methods for measuring liquid levels and leak rates in a storage tank, using an acoustic transducer and a quasi-static reference device that positions an acoustic target within a predetermined distance range below the surface of the liquid. A method for measuring the height of the surface of a liquid, i.e., liquid level.

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.

Abstract: An ultrasonic detection system having a flat faced radiator for providing a narrow beam of ultrasonic energy with minimal dispersion. The system includes an ultrasonic transmitter and receiver unit coupled to an ultrasonic transducer for producing ultrasonic energy. The system also includes a planar radiator and a coupling device between the ultrasonic transducer and the planar radiator. An encapsulating member surrounds the ultrasonic transducer for damping ultrasonic energy transmitted by the transducer in all but one direction. The encapsulating member is also coupled to the planar radiator in areas of the planar radiator that are not coupled to the coupling means. The encapsulating member has an area of increased density immediately adjacent to the planar radiator for damping the ultrasonic energy in areas of the planar radiator that are not directly coupled to the coupling means.

Abstract: A device is provided for detecting the ullage level and flow in a vessel by detecting the presence of a solid or liquid material in proximity to a microwave detector. The device may be mounted to the side of the vessel or suspended inside the vessel so as to bring the microwave sensor into proximity with the surface of the contents of the vessel. A microwave bridge circuit may be used to detect a change in either the amplitude or phase of a signal reflected by the material within the vessel compared to a reference signal tuned to either the presence or absence of the anticipated solid or liquid material. In one embodiment, the reflected material signal is compared to the signal from a sample chamber containing the material to be detected. The device can reliably detect the level of multiple interfaces for various materials having distinct electric or magnetic properties.