Abstract: A filling level measuring probe detects the filling level in a container by suppression of an oscillator by contact with a filling material. The oscillator consists of a hollow body 16, which can be connected through a shaft 14 and a screw-in part 12 with a container wall 10 and is set in oscillation with oscillations in the radial direction over a crosspiece 20 mounted in hollow body 16 by means of an electromechanical transducer 26 which is mounted on crosspiece 20. The oscillations are converted by a second electromechanical transducer 28 into an electric signal, of which the amplitude is changed with suppression of the oscillations as a result of contact of the hollow body 16 with the filling material.

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.

Abstract: A parameter such as the depth (d) of a liquid (12) in a tank (10) is measured by use of an ultrasonic transducer (14) outside the tank (10). This is possible by choosing the ultrasonic frequency and the thickness of the tank wall such that a defined relationship is satisfied.

Abstract: An ultrasonic, echo-ranging instrument for measuring the level of liquid in an open channel or tank. The instrument includes a transducer disposed at a fixed position directly above the liquid surface, the nature of the gaseous environment therebetween determining the velocity of ultrasonic energy propagated therethrough. The transducer is excited to emit periodic pulses which are intercepted by the liquid surface and by a reference point a fixed distance from the transducer to produce both reference and liquid echo pulses that are returned to the transducer and detected thereby. The respective transit times of the reference echo and the liquid echo pulses are determined, and the ratio between these transit times is computed to provide an output representing the level of liquid independent of changes in the gaseous environment. To ensure accurate readings, the reference echo and liquid echo pulses from the transducer are fed to a single automatic gain control circuit whose operation is time shared.

Abstract: A load-sensitive level detecting device for detecting the level of a powder or liquid comprises a piezoelectric vibrator (3), a case (1) which separates the object whose level is to be detected from the latter, the case (1) being formed with an opening (1b), which is closed by an elastic sheet (2) serving as a movable detecting section, whereby when the load exerted by the object is applied to the elastic sheet (2), the vibration of the piezoelectric vibrator (3) is constrained.

Abstract: A sensor for detecting the level of oil in the crankcase of an internal combustion engine. The sensor has a generally tubular body and at one end a thin metal plate to which is bonded the piezo-electric element. The plate, and hence the piezo-electric element, are oriented in the crankcase such that they are generally perpendicular to the level of the oil within the crankcase.

Abstract: A microwave tank-contents level measuring system is housed within a housing having an open end obturated by a hyperbolically curved convex-plano fluid impermeable solid dielectric lens providing a seal for the tank opening over which the housing is installed while collimating the outgoing ranging signal and focusing the return signal. A separate removable housing cover provides access to the electronic components for service while the tank-opening sealing function of the lens is not disturbed. A transmitting-receiving horn is dimensioned and positioned on the axis of the lens with its effective phase center at the operating frequency coinciding with a focal point of the hyperbolic surface.

Abstract: Process and apparatus for detecting and locating a change of composition in a medium, which consists in determining the speed of transmission of an ultrasonic wave through a layer or column of the medium; this determination is effected at a plurality of locations or levels and those of the locations or levels are noted which correspond to changes in the speed of transmission of the wave.

Abstract: Apparatus for detecting failure of a surface tension screen disposed between a holding chamber and a main chamber of a tank includes a fixture for supporting the tank in desired test orientations, a drive mechanism on the fixture for rotating the tank and an ultrasonic transducer used in making a measurement with respect to the position of an interface between liquid and gas contained in the holding chamber of the tank. The holding and main chambers are tandemly arranged along a longitudinal axis of the tank and are each substantially filled by a liquid propellant with respective volumes of gas contained in each chamber. The fixture supports the tank in a first orientation with a nose of the tank pointing downwardly and tank longitudinal axis extending approximately 60.degree. above horizontal and to the right of vertical and in a second orientation with the tank nose pointing upwardly and tank longitudinal axis extending approximately 60.degree. above horizontal and to the left of vertical.

Abstract: Energy limiting, bidirectional signal passage, bandpass filtering, and DC isolation is provided in an intrinsically safe manner, for electrical signals coupled between various electrical equipment located both outside and within a storage tank containing highly combustible matter, for example, via apparatus including a ferrite core transformer potted within a cavity of an explosion proof housing mounted upon a wall of the tank, whereby one winding of the transformer is connected to the outside equipment, and another winding of the transformer is connected to equipment located within the tank.

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.

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.

Abstract: A container of known volume, such as a fuel tank of an automotive vehicle, is provided with a loudspeaker-like membrane which can be energized to produce a pressure pulse in the gas space above the liquid in the container. The oscillations of this gas space are then converted into a signal via the diaphragm and the period of the signal is determined to provide the volume of the gas space. This is subtracted from the gas volume of the container automatically to indicate the liquid volume and the liquid volume can be displayed on the dashboard of the vehicle.

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.

Abstract: An ultrasonic liquid quantity measuring apparatus directs a collimated beam of ultrasonic energy from a transmitter transducer (14) through a conveyor (15) into the liquid (11) in a container (10) perpendicular to the top liquid surface. The ultrasonic beam travels with little loss through a tube (20) connected to the conveyor (15) until it reaches the top liquid surface. At this time the energy is reflected and detected with a receiver transducer (14). A microprocessor (34) measures the total signal round trip travel time representing the height of the liquid (11). Using several ultrasonic transducers (14) and knowing the size and shape of the container (10) the quantity of liquid (11) in the container (10) is accurately determined. A calibration (known reflected signal time) transducer (14a) is used to compensate for the change in propagation velocity due to temperature change in the liquid (11).

Abstract: A method and device for measuring the fluid level in a container. A column f fluid within the container is momentarily subjected to pressure, which causes the column of fluid to vibrate. The oscillation frequency is then measured. Since the frequency depends on the fluid level, the fluid level may be determined from the frequency of oscillation.

Abstract: An acoustic system is provided for measuring the fluid level in oil, gas or water wells under pressure conditions that does not require an electrical link to the surface for level detection. A battery powered sound transmitter is integrated with a liquid sensor in the form of a conductivity probe, enclosed in a sealed housing which is lowered into a well by means of a wire line reel assembly. The sound transmitter generates an intense identifiable acoustic emission when the sensor contacts liquid in the well. The acoustic emissions propagate up the well which functions as a waveguide and are detected by an acoustic transducer. The output signal from the transducer is filtered to provide noise rejection outside of the acoustic signal spectrum. The filtered signal is used to indicate to an operator the liquid level in the well has been reached and the depth is read from a footage counter coupled with the wire line reel assembly at the instant the sound signal is received.

Abstract: Apparatus for measuring and indicating the settlement of the floor of a large liquid containing vessel such as an oil storage tank. The apparatus comprises sonic echo sounding means positioned at or movable between each of a multiplicity of spaced points disposed within the vessel and above its floor in known relationship one with another, and ranging means for furnishing for each point, and upon the basis of the echo sounding means output, a measure of the distance from the point to the vessel floor and an indicator (preferably visual) for indicating from the ranging results the settlement of the floor below those points. In preferred embodiments, the surface of the liquid within the vessel is utilized as a datum and the arrangement may be adapted to provide an indication of the volume of liquid within the vessel.

Abstract: A gas gun for producing pressure pulses for measuring the liquid level in a well. A body is adapted to be connected to a well and includes first and second chambers which are interconnected by a passageway. Pressure pulses flowing between the chambers creates a pressure pulse for transmittal to a well which is measured by a microphone measuring pressure variations. A piston actuated valve opens and closes the passageway between the first and second chambers. A firing valve transmits the higher pressure in one of the chambers to the back of the piston for closing the valve, and after one of the chambers is pressurized, exhausts the pressure from the back of the pressurized piston for opening the valve and creating a pressure pulse between the chambers. A spring biases the piston actuated valve to the closed position.

Abstract: The level detector is to be used for starting and stopping an electric system such as a pump. It comprises a piezo-electric crystal (31) squeezingly mounted between two elastically resilient membranes (22, 23) situated between two squeezing members (11, 12). These squeezing members form a top part (11) and a bottom part (12), respectively, which together form a sensor housing (10). On the outside the membranes are coated with a thin, insulating plastic layer (21, 24) and form the electric connection to the crystal. The two membranes are kept separated by means of a plurality of insulating, annular disks (25-28). In this manner a sturdy and reliable mounting of the piezo-electric crystal is obtained.

Abstract: An offshore drilling tower has at least one upright hollow member extending from below the water to support an above-water platform. A detector in or on the hollow member, usually below the water, responds to a water leak into the hollow member. The detector includes a signal generator responsive to pressure or chemical effect of the water. The detector is effective when actuated by water intrusion into the hollow member and into contact with the detector to send a signal of a unique or distinct frequency through the member itself to a signal receiver, preferably on the platform. The receiver is tuned to the distinct frequency and is effective upon receipt of such signal to afford an indication that the detector has been actuated by a water leak at a particular location.

Abstract: A device for the determination of the charging level in a container has a vibrator on which two torsional vibrators (10, 12) of the same resonance frequency vibrate in an opposite way. The vibration elements (10, 12) are arranged coaxially and have a common center of rotation (20) which is located in the center of a diaphragm (14) serving as a return spring for the outer element (10). The inner element (12) is designed in the shape of a rod and has a tapering (17) in the area of the center of rotation (20) acting as a return spring. Owing to the design according to the invention, a charging level determination is possible with goods charged of a high and of a low density whereby the detection sensitivity is almost independent of the clamping conditions of the vibrator.

Abstract: The invention relates to a method of ultrasonic measurement of the ratio of the volume of gas present in an enclosure containing a diphase liquid-gas mixture to the volume of the enclosure, or void coefficient. Waves at different frequencies are propagated through the fluid filling the enclosure (1). The propagation times of the waves are measured and the difference between these propagation times is calculated. If the propagation times are identical, it is deduced that all the gas is in the form of a layer surmounting the liquid. The void coefficient is determined from the propagation velocities of the ultrasounds in the gas and the liquid and from the measured propagation time. If the propagation times are different, a part of the gas is in the form of bubbles in the liquid, the void coefficient due to the gas surmounting the liquid and the void coefficient due to the gas bubbles in the liquid are determined separately. The total void coefficient is determined by adding the two values obtained.

Abstract: A storage tank level monitoring apparatus and method for determining fluid levels in a storage tank. The apparatus of the present invention includes a magnet coated with rubber for holding a pivotally mounted housing to the interior of the storage tank and an ultrasonic transducer contained within the housing for generating acoustic pulses and for receiving reflections of the acoustic pulses for producing an analog signal proportional to the reflections, a string carrying a number of reference disks vertically oriented below the housing for producing a series of reflected acoustic signals from each reference disk, and a processor connected to the ultrasonic transducer for activating the transducer and for analyzing the reflected pulses for calibrating the apparatus for environmental changes in the atmosphere above the stored fluid and for determining the level of the stored fluid in the tank.

Abstract: The invention relates an apparatus for measuring and indicating the fluid level in a vessel, such as larger LP-gas tubes for household purposes.A pulse device is used for causing the vessel wall to vibrate, for example by causing a striking pin momentarily to thrust against the wall, and for scanning the oscillation frequency of the wall varying with the filling degree of the vessel. A transducer is provided which, for example, is a piezoelectric element abutting the wall. The output signal from the element is passed to a processing unit for evaluating the signal, and the result is passed to an indicator, which may be of the analog or digital type.

Abstract: An ink level control for a printing press is disclosed having an ultrasonic ink level sensor to receive an echo signal representative of the level of the ink in the ink fountain. A control is provided whereby the ink level is maintained at a desired operating level and conditions of excessively low and high ink levels are also detected by the sensor. An echo loss detection network is provided to warn the operator and inhibit ink feeds. The control is designed to prevent overflow of the ink fountain.

Abstract: The volume of gases in a container or the volume of liquid in the container is determined by creating cyclic pressure waves in the gases and detecting the waves by a second transducer. The signals produced by the second transducer are a function of the volume of gas in the container, and the volume of any liquid can be obtained by simple calculation. The signals can also provide detection of an open container and, when coupled to signals relating to the velocity of a vehicle, can provide other data such as a miles-per-gallon reading.

Abstract: An ultrasonic echo-ranging system adopted to measure the level of liquid in an open channel or other liquid container. The system includes an ultrasonic transducer disposed at a fixed position directly above the liquid surface, the nature of the gaseous environment therebetween determining the velocity of ultrasonic energy propagated therethrough. The transducer is excited to emit periodic pulses which are directed along a center path toward the liquid surface and reflected to produce liquid echo pulses which return to the transducer and are detected thereby. A reference reflector at a predetermined position relative to the transducer intercepts energy from a side path in the radiation pattern of the transducer to return it to the transducer to produce reference echo pulses. Means are provided to determine the transit time of pulses along the center path, and also to determine the transit time along the side path.

Abstract: A urine discharge measuring system for medical use which includes a gimbal mounted frame supporting a urine container of fixed dimensions to collect urine from a urinary catheter attached to a patient. An ultrasonic transceiver mounted above the container and operated in conjunction with a microprocessor based control unit, positioned adjacent to the transceiver, periodically and automatically measures the height of the urine collected within the container. The measured fluid height is converted to fluid volume by the control unit. To maintain the sterility of the container, the transceiver transducer(s) is mechanically isolated from the urine container by elements which allow the ultrasonic energy to be transmitted to and received from the interior of the container. In one described embodiment, desired measured volume accuracy is achieved by employing a reflective target within the urine container at a known fixed distance from the transceiver transducer.

Abstract: An inlet tube, connected to a source of liquid, such as milk, supplies liquid to the top of a container. An orifice at the bottom of the container permits drainage from the container into an outlet tube. The level of liquid in the container is related to the instantaneous flow rate, in a known manner, as long as the pressure in the container, above the liquid surface, equals the pressure in the outlet tube after the orifice. A conduit connects the upper portion of the container, at a point above the liquid therein, and the outlet tube, below the orifice, to equalize the pressure therebetween, as well as to act as an overflow bypass. Various types of sensors may be used to determine the level of liquid in the container. A signal, representative of the sensed liquid level, is developed and processed to represent the flow rate.

Abstract: An ultrasonic detector, particularly useful in the level detection of blood within an arterial reservoir, is provided. The detector includes a pair of opposed arms for connection to the arterial reservoir. One of the arms carries a transmitting transducer while the other arm carries a receiving transducer facing the transmitting transducer. A clamping ring is slidable on both arms for forcing the arms toward each other when the ring is moved in one direction and for enabling the arms to move apart from each other when the ring is moved in the opposite direction.

Abstract: A liquid storage and measurement system particularly applicable to the volumetric measurement of siquid hydrocarbon fuel and to the dispensing of the fuel via a fuel dispensing unit, includes a liquid measurement/storage vessel of known dimensions arranged to be partially filled with liquid, e.g.

Abstract: An ultrasonic measuring sensor for the fixing station of a non-mechanical printing or copying device has an electroacoustical transducer for both transmitting and receiving ultrasonic oscillation, and a reflector spaced a distance from the transducer for reflecting the oscillation transmitted by the transducer back to the transducer. The measuring path between the transducer and the reflector is surrounded by a fine mesh net having a mesh size which is significantly smaller than the wavelength of the ultrasonic oscillation. The mesh of the net is selected so as to permit the vapor concentration inside of the net to follow the changes in the average concentration at the fixing station with sufficient rapidity while shielding the measuring path against brief and topically limited concentration fluctuations.

Abstract: The apparatus provides for detection of variation in acoustic properties at a metal to air interface (18) such as may be caused by arrival of drops of leaking liquid. Ultrasonic signal pulses from transducer (14) are reflected many times back and forth across rod (11) between the transducer and the interface (18). Change in diminution of amplitude with successive reflection can be detected over a multiplicity (e.g. 10) of reflections and indicates change in the acoustic properties of the interface. Comparison is made between a selected early reflected signal pulse and a selected later reflection. Response is inhibited in respect of intermediate reflections.

Abstract: A motionless viscometer and associated method for resinous materials including polymeric foams and non-resinous materials includes a reservoir section, a receiver section and an interposed tube. As the foam is expanded the axial pressure within the connecting tube is measured as is the rate of rise of the foam within the receiver element. Shear viscosity and density as functions of time may be determined.

Abstract: Measurement of the relative and actual value of acoustic characteristic impedances of an unknown substance, location of the interfaces of vertically-layered materials, and the determination of the concentration of a first material mixed in a second material. A highly damped ultrasonic pulse is transmitted into one side of a reference plate, such as a tank wall, where the other side of the reference plate is in physical contact with the medium to be measured. The amplitude of a return signal, which is the reflection of the transmitted pulse from the interface between the other side of the reference plate and the medium, is measured. The amplitude value indicates the acoustic characteristic impedance of the substance relative to that of the reference plate or relative to that of other tested materials. Discontinuities in amplitude with repeated measurements for various heights indicate the location of interfaces in vertically-layered materials.

Abstract: An improved transceiver for use in ultrasonic echo-ranging systems is disclosed together with a system for its use. The transceiver comprises a capacitor to store power received from a central location during an inactive mode, and switching means to disconnect the capacitor from the power supply during the active mode. The capacitor is used both to supply power to an electrostatic transducer to generate an ultrasonic pulse and also to provide a noise free bias voltage to the transducer to enable it to receive the reflected pulse. An amplifier is provided as part of the transceiver so that long transmission lines between transceiver and controller are possible without undue noise. The power supply line can also be used as the signal transmission line and can be provided in a simple two-wire shielded cable, the other wire being used for logic level control signal transmission, thus allowing simplified multiplexing of a plurality of transceivers.

Abstract: Apparatus for determining the location of the liquid level in a well or borehole. A source of acoustic pressure pulses is coupled to the surface casing so that they are transmitted down the well and reflected by the gas-liquid interface. A transducer is also coupled to the well to produce an electrical signal in response to direct and reflected acoustic pulses occurring in the well. Gating circuitry responds to the transducer for starting and stopping the counting of clock pulses by a digital counter. A digital readout device is used to indicate the depth to the liquid level in the well. The acoustic pulse source is automatically actuated at predetermined times, and the depth to the liquid level and the time are automatically recorded. This produces a record of time and liquid depth which can extend over a period of several days.

Abstract: A sewer flow monitoring system wherein the depth of fluid in a pipe is measured in pairs of transmitter-receiver ultrasonic ranging transducers. Each measurement sample is tested against a selected range criteria and against other samples, and the determined good samples are then averaged. Short range detection capability is obtained by varying the response of signal processing wherein an attenuating effect decreases with time following a transmitted pulse.

Abstract: A liquid-level measuring device including, in effect, two similar elongate members each adapted to be partially submerged in a liquid, the two elongate members being displaced lengthwise relative to one another by an odd number of quarter wavelengths of a predetermined wavelength of a chosen flexurally resonant mode of the elongate members. Each elongate member has flexure wave transmitting elements in contact therewith for launching flexure waves along the member and flexure wave receiving elements in contact with the member for receiving flexure waves launched by the transmitting elements. Also, associated with each elongate member is a phase detection arrangement connected both to the transmitting elements and to the receiving elements for detecting and comparing the phase of the flexure waves at the transmitting elements with the phase at the receiving elements so as to obtain a phase difference measurement, the magnitude of which provides an indication of the resonance frequency of the elongate member.

Abstract: A method and apparatus for measuring the amount of mire and mud in a suction dredge hopper 2, which mire and mud is a constituent of a fluidized mixture. An acoustic level gauge 16 measured the position of the upper surface 3 of the mixture and a plumb weight 7 measures the position of the lower limit of the mixture defined by the top of a sand layer 4. A plurality of differential pressure responsive density measuring devices P measure the density of mire at different levels. From these measured valves the total amount of mud and mire is determined.

Abstract: Apparatus to detect and/or locate an inhomogeneity in a medium comprises a transducer to transmit frequency-modulated ultrasonic energy through the medium and a transducer to receive reflected energy. The transducers are connected to a phase-locked loop which maintains a required relationship between the phase of the transmitted modulation and the phase of the received modulation by adjustment of the modulation frequency. The modulation frequency adjustment is kept within predetermined upper and lower frequency limits so that the loop can lock only on to received ultrasonic energy which has travelled a distance within a predetermined region in the medium. The energy may be scanned across the region to produce a profile of the inhomogeneity, such as tissue at a certain depth within a limb.

Abstract: In a steam generator an ultrasonic probe is used to measure the accumulation of sludge between the tubes. A ribbon-like probe carrier is fed into the vessel and deflected by a carriage placed in alignment with a lane of tubes at 90.degree., the probe head being advanced in the lane to measure vertically and sideways the distance to the surface of the sludge. The probe carrier consists of two steel tapes held face-to-face by a plastic tube which has been heat shrunk. The conductors for the transducers are contained in the space between concave tapes. An adaptor mounted at the end of the probe carrier is amovably connected to the probe head. Probe head, adaptor and probe carrier are sealed so that measurement can be conducted inside the steam generator supposedly filled with water.

Abstract: A system is provided for detecting the absence of liquid in a liquid chamber. A signal is transmitted through a liquid chamber and a signal is provided in response to the amplitude of the received signal. A receiving transducer receives an AC signal which is amplified and fed to a DC control circuit. A reference voltage is provided to one input of a comparator and the output of the DC control circuit is fed to the other input of the comparator. The comparator output provides the liquid absence signal if the difference between the reference voltage and the DC control circuit output voltage is less than a predetermined value.

Abstract: A device for measuring the depth and temperature of a liquid stored in a tank is provided. The device includes a hermetically sealed vertically disposed tube having ultrasonic transmitter/receiver devices at either end thereof with a reflector vertically movable in the tube and having a through-hole therein permitting transmission from one end of the tube to the other as well as reflection. A float encircles the tube and moves up and down with the level of liquid in the storage tank. The float and reflector are magnetically interconnected so that the reflector moves up and down with the float.

Abstract: A highly sensitive liquid level detection system. It employs a piezoelectric transducer that has a natural frequency of vibration which effectively varies depending upon the amount that the transducer is immersed in a liquid. An emf is applied to the transducer to cause it to vibrate at the effective natural frequency, and the exact frequency is counted which count indicates the amount of immersion with a high degree of accuracy. A printer may be employed to periodically record the frequency count.

Abstract: Ultrasonic apparatus and method measures the characteristics of materials by sensing changes in the impedance to applied drive excitation of an ultrasonic probe using a crystal sensor that is integral with the ultrasonic transducer.

Abstract: To provide a precise determination and/or control of a filling level in containers, two vibrator elements (10, 12; 48, 52) are arranged one on top of the other and/or coaxially to each other, and at least partially encompass themselves in spaced relation to each other. They are configured like rotary vibrators having the same resonance frequency and are excited to vibrations of opposite sense of rotation for determining the filling level, whereby only one vibrator element comes into direct contact with the filling material in the container. This results in no vibration energy being transmitted to the container walls and thus the quality of the measurements is increased.

Abstract: An ultrasonic system that measures either the impedance of a fluid or liquid level utilizes moderately directional, bulk SV mode sound waves generated by a transducer and propagated in a homogeneous, flaw-free solid member. The SV wave propagates in the solid along a zigzag path that reflects at a solid-fluid interface in at least two areas and at an angle of incidence that exceeds the first critical angle by at least five degrees and is less than the second critical angle by at least ten degrees. The attenuated amplitude of the wave due to acoustic coupling between the solid and the fluid measures the impedance or an impedance related parameter of the fluid. The system preferably includes a second acoustic path that serves as a reference to compensate for changes in parameters such as temperature, the nature of the fluid, the transducer, the transducer coupling, and residues or corrosion at the solid-fluid interface.

Abstract: Apparatus for determining the location of the liquid level in a well or borehole. A source of acoustic pressure pulses is coupled to the surface casing so that they are transmitted down the well and reflected by the gas-liquid interface. A transducer is also coupled to the well to produce an electrical signal in response to direct and reflected acoustic pulses occurring in the well. Gating circuitry responds to the transducer for starting and stopping the counting of clock pulses by a digital counter. A digital readout device is used to indicate the depth to the liquid level in the well. The acoustic pulse source is automatically actuated at predetermined times, and the depth to the liquid level and the time are automatically recorded. This produces a record of time and liquid depth which can extend over a period of several days.