Abstract: A vibrating probe for detecting a threshold level of solids within a vessel consists of an ultrasonic acoustic transducer assembly having a resonant frequency, the assembly being supported within the vessel and including a coupling member to couple the transducer acoustically to the solids at the threshold level, a transmitter for generating repeated bursts of high-frequency electrical energy and applying them to the transducer, the bursts being of sufficient amplitude to render the assembly self cleaning of adherent solids, a circuit for measuring the amplitude of ringing of the transducer after cessation of each burst, and a circuit for comparing the amplitude of such ringing at a predetermined interval after a burst with predetermined threshold level. Both the predetermined interval and the threshold level may be selectable.

Abstract: A small, compact, easily mountable ultrasonic transducer for measuring the filling level in a container is provided, which transducer transmits virtually no oscillation energy to the container, having a can-shaped transducer housing (1), an electronics housing (2) connected to the transducer housing (1), a transducer element (4), arranged in the transducer housing (1), for the transmission and reception of ultrasonic pulses, a union ring (3) for the sound-decoupling securing of the ultrasonic transducer on the container, in which ring the transducer housing (1) is supported coaxially with respect to the union ring (3) and is fixed therein against displacement in the axial direction, and two resilient elements (7, 8) which are arranged between the transducer housing (1) and the union ring (3) and by means of which the transducer housing (1) and the union ring (3) are held spaced apart from each other in the radial direction in such a way that there is no direct mechanical coupling between them in the radial di

Abstract: A method of detecting the displacement of a target in a given environment includes storing reference data having data representative of the environment; transmitting a transmit signal towards the target; sensing the return signals from the target and the environment; and detecting the displacement of the target by comparing the return signals and the stored reference data. A method of detecting the level of a sample in a container is also disclosed. Analogous apparatus features are also disclosed.

Abstract: For monitoring a predetermined level of a liquid in a container an ultrasonic transducer is fitted on the outer surface of the container wall at a measurement point situated at the height of the level to be monitored. The ultrasonic transducer contains a piezoelectric element which generates, when excited by an alternating voltage pulse having a given transmission frequency, an ultrasonic transmission pulse which is transferred via a diaphragm to the container wall and which converts ultrasonic vibrations transferred from the container wall to the ultrasonic transducer into electrical reception signals. The diaphragm comprises on the side facing the container wall protuberances which adjoin the container wall. Between the diaphragm and the container wall a coupling layer is arranged, the thickness of which is determined by the height of the protuberances.

Abstract: An acoustic method is disclosed for measuring fluid level in producing wells and other inaccessible cavities. The method uses flow induced pressure phenomena to locate the fluid level. Simplified equipment is involved and acoustic velocities can be measured externally from the well. The method applies to known uses for fluid levels such as well productivity, lift equipment design, and reservoir studies.

Abstract: Apparatus for indicating material level that includes a pair of ultrasonic transducers on opposed sides of a space for receiving the material at the level to be detected. A swept frequency oscillator is coupled to one of the transducers so that the transducer radiates into the material space ultrasonic energy that continuously sweeps back and forth between a low frequency range at which such energy is transmitted to the other transducer by resonance of the entire apparatus and independent of presence of material in the material space, and a higher frequency range at which such energy is transmitted to the other transducer only when material is present in the space between the transducers. Detection circuitry indicates presence of material between the transducers upon receipt of the higher frequency energy, and failure of the apparatus upon failure to receive the lower frequency energy.

Abstract: The displacement sensor of this invention comprises a tube combined with a sonic transmitter and receiver. The tube acts as a waveguide for the sonic waves and a processor determines whether the tube has changed in length or has been constricted which, in either case, changes the pattern of sonic waves traveling from the transmitter to the receiver. In some applications, the transmitter and receiver are at different ends of the tube. In these cases, the attenuation in sound energy reaching the receiver, caused by the tube being squeezed at at least one point, is measured and the amount of cross action area reduction is determined. In other applications, the transmitter and receiver are at the same end of the tube and, in some of these cases, the transmitter and receiver are the same transducer.

Abstract: In a first step, an individual echo is associated with each local maxima in the received ultrasonic signal. Subsequently, characteristic features such as time position, amplitude and form factor of each respective individual echo are detected numerically for the individual echo. In a second step, the mentioned features are subjected to a fuzzy evaluation. The features form the input variables of the evaluation. A multiple echo probability for each individual echo is available as the result. With this awareness, with the aid of the a priori knowledge and with the aid of the awareness of the history, it is possible, for example, to draw conclusions concerning the filling level of the bulk material in containers in which the surface of the bulk material is at times masked for the ultrasonic beam by the stirring apparatus.

Abstract: A container having affixed thereto an ultrasonic transducer, including a connection for electrically linking the transducer to electronic circuitry located outside the container. Flexible and semi-rigid containers having rigid structures surrounding the signal path of an ultrasonic transducer are also provided. In addition, adaptors are disclosed for use in connecting an ultrasonic transducer to a container. Such adaptors can include a rigid tubular member, a tubular outlet connected to the tubular member for draining liquid from a container, and a seat for engaging an ultrasonic transducer.

Abstract: An ultrasonic probe utilized in an ultrasonic ranging system for determining fluid volume and/or fluid leakage in an underground storage tank, as well as monitoring fluid inventory, is provided which is characterized by (i) having its calibration reflectors positioned whereby each of the secondary echo packets formed by the calibration reflectors of the ultrasonic probe becomes imbedded into the trailing edge of a primary echo packet of another calibration reflector or to cause its secondary echo packet to be detected by the transducer after the transducer has detected a primary echo packet associated with the fluid surface, (ii) each of the calibration reflectors being positioned perpendicular to and offset from the longitudinal axis of the probe body, (iii) an ultrasonic sound wave dampening member fixedly positioned in the probe body between the transducer assembly and the tank bottom, the wave dampening member having a surface facing toward the transducer assembly wherein the surface is configured to damp

Abstract: A vertical acoustic array system and method for acoustically imaging the tents of a partially or completely buried tank which can contain radioactive solids and may not be entirely filled. The transducer array is placed proximate a side of a tank in a vessel such as a tube filled with water. Dirt or other filler material located between the tube and the tank is saturated with water, allowing the acoustic signal to propagate through the side of the tank and into the tank. The vertical array consists of one or more transmitting units and receiving units set in a vertical array including dipole receiving elements which allow horizontal directionality. The signals are analyzed by a field unit which includes a portable self-powered trailer providing signal transmitting and analysis devices. The field unit can transmit signals to a second unit which provides further signal analysis.

Abstract: An ultrasound transducer includes a resonant driving assembly having an ultrasound radiating surface covered with a propagation disc of impedance matching material. The resonant driving assembly and propagation disc are housed in a polymeric or stainless steel enclosure. All exposed surfaces of the enclosure, resonant driving assembly, and disc are covered with a coating of polyparaxylylene to make the transducer substantially impervious to industrial chemicals.

Abstract: A transducer assembly for a proximity sensor which comprises an elongated polymer piezoelectric film (16). The film is supported as an elongated series of arcuate segments which are curved in the same direction and have the same radius of curvature. Electrodes (18) on both sides of the piezoelectric film form opposed pairs, each pair being associated with a respective arcuate segment. The electrodes are utilized for applying a varying electric field across the thickness of the film to cause an ultrasonic acoustic wave to be radiated from the film.

Abstract: A non-intrusive mounting system and method for coupling microwave instruments to a container flange having an opening into a container. The mounting system includes a microwave transparent window and a mounting flange having a window recess for accommodating the microwave transparent window. The microwave transparent window is compressively fastened over the container opening between the mounting flange and the container flange. Microwave instruments such as radar level sensing apparatus can be mounted on and removed from the mounting flange without breaking the seal to the container.

Abstract: The ultrasonic transmitter (E) is subjected to two different excitation modes, and is mounted on the support (2) which at the same constitutes a waveguide.Excitation of the transmitter at its axial-resonance frequency transmits ultrasonic waves through the liquid to provide a detection signal. Its excitation at its radial-resonance frequency creates ultrasonic waves propagated along the support (2) to provide an operation-control signal.The invention is applicable to the detection of various liquids in a broad range of conditions and is suitable for industrial applications, notably in safety and control systems.

Abstract: A noninvasive ultrasonic liquid level indicator for indicating the level of a liquid in a reservoir is disclosed which comprises an ultrasonic transducer assembly, structures for holding the transducer assembly in a dry coupled attachment with the reservoir at selectable locations against an exterior surface of the reservoir, and a monitor for revealing a change in liquid height. The transducer assembly conveys signals regarding changes in liquid height to a monitor which warns the user in time to add more liquid or replace the reservoir before the liquid supply "runs dry." The manners for holding the assembly in place include, but are not limited to, a strap, a clamp, or adhesive material, such as tape. These allow the user to selectively place the transducer assembly along the reservoir at the desired triggering point.

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: An apparatus for continuously monitoring changes in a liquid level in accance with a differential pressure is provided. A sensor body immersed in the liquid supports two thin-filmed metallic diaphragms that are independently, axially responsive to pressure of the liquid. Each diaphragm has a different modulus of elasticity. Two fiber optic pressure sensors are mounted within an air space encased by the sensor body in combination with the two diaphragms. Each of the two fiber optic pressure sensors detects the axial response of one of the two diaphragms. The displacement difference between the two diaphragms is an indication of differential pressure related to the liquid level.

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: A real time ultrasonic surface contour mapping system is provided including a digitally controlled phased-array of transmitter/receiver (T/R) elements located in a fixed position above the surface to be mapped. The surface is divided into a predetermined number of pixels which are separately scanned by an arrangement of T/R elements by applying phase delayed signals thereto that produce ultrasonic tone bursts from each T/R that arrive at a point X in phase and at the same time relative to the leading edge of the tone burst pulse so that the acoustic energies from each T/R combine in a reinforcing manner at point X. The signals produced by the reception of the echo signals reflected from point X back to the T/Rs are also delayed appropriately so that they add in phase at the input of a signal combiner. This combined signal is then processed to determine the range to the point X using density-corrected sound velocity values.

Abstract: For the measurement of distance using the pulse transit time principle the received signal produced after each transmission of a pulse is stored as an echo profile and the effective echo is determined from the stored echo profile. In order to suppress recurrent interfering signals a stationary threshold profile adapted to the measurement environment is formed and employed for each evaluation of a stored echo profile. In order to take into account fluctuations in the properties of the received echo profile rapidly without necessitating a modification in the stationary threshold profile for this, from a stored echo profile a floating threshold profile is generated in the form of a monotonously descending curve. From the mutually corresponding values of the floating threshold profile and of the stationary threshold profile the respectively larger value is utilized for the formation of a resulting threshold profile, which is employed for each evaluation of stored echo profiles.

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: An intrusive fluid sensor mounting arrangement for a fluid container includes first and second tubes, the first tube being attachable to a wall of the container such that a first end of the first tube is open to the container exterior through the container wall and a second end of the first tube extends into the container; the second tube being sized to slide axially within the first tube between first and second positions; the second tube having a first end accessible from outside the container such that a sensor can be installed in and removed from the second tube; the second tube providing fluid communication between the sensor and fluid in the container when the second tube is in the first position, and substantially preventing fluid loss from the container when the second tube is in the second position.

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: There is provided a hermetically sealed dry-coupled transducer apparatus and system adapted for improved measuring of liquid level in a pipe or vessel, or for other instrumentation applications. The transducer system is characterized by having a hermetic seal at the junction of an acoustic window 33' and an outer shell 31' (thereby hermetically sealing a forward aperture of the outer shell), and a thin, compliant, threaded cap 46 enclosing a rearward aperture of the outer shell. The cap provides means for repetitively assembling and disassembling the transducer module, if necessary, prior to welding. In addition, a push rod applies acoustic coupling force to a piezoelectric transducer element to effect dry coupling to a surface, while the compliant cap prevents significant force transmission to the shell. The system exhibits limited reverberation and, moreover, is suitable for use in high-temperature environments.

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: The invention generally pertains to apparatus for determining bedload thickness of a bedload on a bed surface in an aquatic medium. An acoustic source is operative when energized for producing incident acoustic waves in the medium directed at the bed surface resulting in reflected waves. An acoustic sensor is movably locatable between the acoustic source and the bed surface and is responsive to the incident and reflected waves for producing a variable output representative of the sum of the incident and reflected waves. The sum varies between a maximum and a minimum with distance from the bed surface. A height sensor is responsive to the position of the acoustic sensor relative to the bedload thickness for producing an output indicative thereof. A processor responsive to the acoustic sensor output and the height sensor output produces an output indicative of the thickness of the bedload thickness.

Abstract: A combined speed and depth transducer adapted to be mounted flush in the hull of a ship. An acoustic depth transducer is mounted piggyback on top of an acoustic speed transducer within a single housing. A base plate is sandwiched between the depth transducer and the speed transducer. The dimensions and frequency of transmission of the transducers are selected to prevent ringing in one transducer that may be caused by the acoustic wave of the other transducer. The base plate 40 is constructed to damp the acoustic wave transmitted by the speed transducer and be transparent to the acoustic wave transmitted by the depth transducer. Having the depth and speed transducers mounted within a common housing, and flush with the hull of the ship, provides the advantage of having to make only a single hole in the hull as well as having a low drag.

Abstract: The objects of the present invention are achieved by temporarily suspending sonar beam transducer means at a first underwater location within sonar beam range of said scoured area; scanning a first portion of said scoured area with said sonar beam in a first substantially vertical plane that points in a first azimuth direction, so as to generate signals indicative of the range and bearing of said scanned first portion from said transducer means; and scanning at least a second different portion of said scoured area with said sonar beam in a second different substantially vertical plane that points in a second different azimuth direction, so as to generate signals indicative of the range and bearing of said scanned second portion from said transducer means. In actual practice, scanning by the sonar beam occurs in many different vertical planes and also can be done from different underwater locations.

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: 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.

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: An ultrasonic detector of the type used to detect the level of a liquid or the magnitude of liquid flow within a conduit by periodically transmitting ultrasonic energy bursts and receiving echoes therefrom is controlled by a controller with a computer program having a number of routines. The routines include a range search routine that searches a defined range of the detector to locate the targets within the range. The range is searched by repeatedly transmitting energy bursts and gradually decreasing the gain of the detector after the transmission of each burst. All targets identified during the range search are then classified as being either bogus targets or the true target. This classification is made with the use of a bogus buffer in which bogus target data is stored.

Abstract: A system for monitoring level of material in a vessel that includes a transducer for transmitting an ultrasonic signal toward and receiving an echo signal from a surface of the material, and a power switch coupled to the transducer for energizing the transducer to transmit the ultrasonic signal. A microprocessor-based controller has an output coupled to the power switch for controlling operation thereof. The output of the microprocessor provides a pulsed periodic signal to the power switch at controllably variable frequency, duty cycle and/or total burst duration to operate the transducer at an ultrasonic frequency that corresponds to the periodic signal frequency, duty cycle and burst duration. The echo signals are compared to successive thresholds between the transmission bursts, and echo signal data is sampled and stored in the microprocessor over a measurement cycle that includes multiple transmission bursts.

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 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: 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: 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: 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 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.

Abstract: An ultrasonic method and apparatus for measuring liquid level in a vessel employing an acoustic waveguide (16) connected to an ultrasonic transducer (14) and the vessel (18). Guiding means (24) situated inside a vessel (18) directs the acoustic energy pulse to a surface (22) of the liquid. The acoustic energy pulse is reflected from the surface (22) and returned along the guiding means (24) to the acoustic waveguide (16). A pulser/receiver (10) connected thereto measures the reflected acoustic energy pulse for determining liquid level from the transit time.