Abstract: A method of using a firearm shot helmet detection system includes providing a firearm shot detection system comprising a plurality of helmets worn by respective mobile fighters, each helmet including a firearm shot detection system that detects the presence and geographical origination of a firearm shot, and wirelessly communicates with other firearm shot detection systems of other respective helmets; detecting the presence of a firearm shot with the firearm shot detection system of each helmet; wirelessly communicating distance information on the detected firearm shot with the other firearm shot detection systems of other respective helmets; and determining the geographical origination of the firearm shot using triangulation based on the distance information on the detected firearm shot.

Abstract: A method of sonically detecting a sonic act such as a graffiti-making act or firearm shot includes providing a sonic act detection system to sonically detect a sonic act and a camera to take an image of a perpetrator of the sonic act; locating the sonic act detection system and the camera near a location where the sonic act is prone to occur; sonically detecting with said sonic act detection system a sonic act; obtaining one or more images of the perpetrator of the sonic act with the camera; communicating to one or more entities that sonic act has been detected.

Abstract: The invention relates to a device for determining and/or monitoring the level of a filling material in a container. According to the invention, an oscillatable unit is provided which is fastened to a membrane, whereby said oscillatable unit is mounted at the height of the predetermined level. An emitting-receiving unit is provided which, with a given emit frequency, causes the membrane and the oscillatable unit to oscillate, and which receives the oscillations of the oscillatable unit. A control/evaluation unit is provided, which identifies once the predetermined level is obtained upon a given change in frequency or which, with the aid of the oscillation frequency of the oscillatable unit, determines the density of the filling material.

Abstract: The method according to the invention consists in providing two containers fed by the water source whose pollution is desired to be measured, each of the containers containing fish and being equipped with a detector able detect any abnormal behaviour of the fish, alternate the lighting and obscurity periods for said two containers, carry out the detection of the behaviour of the fish in the two containers and trigger an alarm signal when the detection shows an abnormal behaviour of the fish.

Abstract: A continuous measurement of the level of contents in a container is effected by a level measuring device functionong in accordance with the transit time principle by means of waves transmitted from a position located above the highest possible contents level onto the surface of the material in the container. A measuring circuit determines the contents level from the transit time of the useful echo reflected from the material surface. In addition, one or more limit sensors are located at the container, each of which furnishes a signal indicating whether the contents level is above or below a level to be monitored by the limit sensor and which is situated between the minimum and maximum contents levels of the container. The measuring circuit receives the output signals of all limit sensors and uses these output signals to check and eventually to correct the contents level measured value determined by the level measuring device.

Abstract: An ultrasonic liquid level sensor instrument that combines a continuous transmitter that transmits though the air for measuring the level of liquid in a vessel on a continuous basis and a point level sensor that sets a high level alarm. The continuous level transmitter/receiver provides a continuous measurement of the liquid level in the vessel and the point level sensor is used for sensing an overflow, or high level condition in the vessel, as well as failure of the continuous transmitter/receiver. The instrument includes a sensor fixture that holds both the continuous air transmitter/receiver transducer and the point level sensor. The fixture is mounted in a single hole in the wall of a tank or a vessel in which the liquid level is being monitored. Each of the continuous level transmitter/receiver and point level sections of the instrument has a self check capability.

Abstract: In order to detect a filling process, a signal is emitted into the container and an echo reflected from the container is recorded. At least one parameter, e.g., the amplitude h(t) of the reflected echo at a time t, is determined, and a filling process is detected if the parameter lies outside an expected range.

Abstract: Resonant decay sensors that determine a parameter based on the decay of acoustic standing waves in a tube. Parameters that can be determined include temperature, pressure, the level of a material in the tube, and the height of a material above an end of the tube. Resonant decay sensors can produce both point level and continuous level sensors. A vibration mount, such as a rubber ring, beneficially isolates an acoustic transducer from the body of the tube.

Abstract: The invention provides a piezoelectric liquid gauge system in particular for a motor vehicle fuel tank, the system comprising piezoelectric means suitable for transmitting a sound wave in a liquid and for detecting said wave in order to determine the distance traveled by the wave in the liquid on the basis of the time between transmission and reception, said piezoelectric means comprising two distinct active piezoelectric portions suitable respectively for directing a sound wave towards a reference obstacle and a sound wave towards the surface of the liquid to be gauged, the system being wherein the pellet is contained in a housing suitable for being fixed in position in the tank in which measurement is to be performed, the reference obstacle extending over a face of the housing which faces one of the active portions, said face also having a measurement opening placed facing the other active portion and suitable for allowing the measurement sound waves to pass through.

Abstract: A system and method for detecting parallel marketing of an item, include forming at least one of a coating and a code on the item, interrogating the at least one of the coating and said code, and determining from the interrogating whether the item has been transferred from an authorized merchant to an unauthorized merchant.

Abstract: Acoustic level sensing by creating, or failing to create, resonance in a tube having a free end. An acoustic transducer at one end of the tube injects sound at a frequency that could produce resonance, depending on whether the free end is open or closed. The drive to the acoustic transducer is then removed, and the sound decay in the tube is monitored to determine if resonance occurred. Based on that determination, a signal is produced that indicates whether a material has or has not closed the free end of the tube. Beneficially, the same acoustic transducer that produces the sound monitors the sound decay. To determine whether resonance has occurred, or to verify system operation, the sound decay at the possible resonant frequency can be compared to the decay at another frequency. Temperature compensation can be performed by attempting to produce resonance at a plurality of frequencies.

Abstract: An apparatus for determining the filling level of a product in a container with a transmission unit which generates high-frequency signals and emits them at a predetermined pulse repetition frequency in the direction of the surface of the filled product. The signals are reflected by the surface of the filled product and are received by a receiving unit. A delay circuit transforms the high-frequency signals/reflected signals into low-frequency signals in accordance with a predetermined translation factor and with an evaluation unit which determines the filling level of the product in the container on the basis of the delay time of the signals. The delay circuit includes: a transmission oscillator; a sampling oscillator; a digital sampling circuit; and a closed-loop/open-loop control unit.

Abstract: An material level monitoring and reporting system uses special micropower impulse radar level sensing probes, with one such probe being inserted into each of a plurality of material containment structures, such as storage tanks. The micropower impulse radar probes use flexible waveguides which extend downward to the tank bottom such that micropower radar impulses travel to and from the liquid surface via a wave guide, with the lapse between emission and reception of the impulse indicating a distance from the probe, and thus a liquid level. Each level sensing probe is connected to a communication link which collects level and status information from the level sensing probes and transmits it to a monitoring site. The material level data may be collected from a plurality of intermediate monitoring sites by a central monitoring sites.

Abstract: A device for determining and/or monitoring the level of a medium in a container or for ascertaining the density of a medium in the container embodied as a vibration detector. According to the invention the vibration detector still functions reliably even under extreme process conditions and upon abrupt changes in process conditions. The vibration detector has a tubular inner part provided, which is dimensioned such that it is positioned between the housing wall and a drive/receiving unit, and that the tubular inner part is connected to the housing or to the diaphragm.

Abstract: A non-invasive system and method for measuring liquid level in a vessel utilizes a pair of ultrasonic transducers mounted spaced apart externally on the vessel wall. One of the transducers excites a single pulse of sonic energy that produces a flexural, or elastic, wave in the wall and the second transducer receives the flexural wave to produce an electrical signal waveform corresponding to the travel time of the flexural wave between the two transducers. The electrical waveform signals produced at different times are compared to determine if a phase delay exists between two waveform signals, which indicates that there has been a change in the liquid level condition in the vessel interior space between the two transducers. Measuring the phase delay, or time delay, between the flexural wave components produced at two different times is used to indicate presence or absence of the liquid at a point on the vessel and/or the height of the liquid in the space.

Abstract: The invention provides a piezoelectric liquid gauge system in particular for a motor vehicle fuel tank, the system comprising piezoelectric means suitable for transmitting a sound wave in a liquid and for detecting said wave in order to determine the distance traveled by the wave in the liquid on the basis of the time between transmission and reception, said piezoelectric means comprising two distinct active piezoelectric portions suitable respectively for directing a sound wave towards a reference obstacle and a sound wave towards the surface of the liquid to be gauged, the system being wherein the pellet is contained in a housing suitable for being fixed in position in the tank in which measurement is to be performed, the reference obstacle extending over a face of the housing which faces one of the active portions, said face also having a measurement opening placed facing the other active portion and suitable for allowing the measurement sound waves to pass through.

Abstract: The present invention involves a system and method for detecting a graffiti-making act such as the spray of a spray paint can, the writing with a felt-marker pen on a surface, and the scratching with an abrasive instrument on a surface. The system includes one or more sensors adapted to sense the graffiti-making act and transmit a signal representative of the graffiti-making act, and a base unit including electronics adapted to process the signal and determined whether the signal represents a graffiti-making act, and a communication device coupled to the electronics and adapted to communicate to one or more entities that a graffiti-making act has been detected. The method includes sonically detecting the graffiti-making act, and initiating an alarm indicating that the graffiti-making act took place.

Abstract: An adapter for holding a sample container includes a main body portion and a tapered body portion that forms a continuation of the main body portion. The tapered body portion includes a mouth opening that is of lesser diameter than the diameter of the main body portion. The mouth opening of the adapter is sized to provide direct support of a sample container which holds a liquid sample. During liquid level sensing ultrasonic waves from an ultrasound detector are reflected back to the sound detector as echoes from the lip flange of the sample container and from the liquid level within the sample container. The tapered surface of the adapter deflects sound echoes away from the sound detector. The adapter is thus invisible to the ultrasound detector. The echo from the liquid level is a variable duration echo and the echo from the lip flange of the sample container is a fixed duration echo that is always of lesser duration than the variable duration echo.

Abstract: A resonance chamber is provided in a printing device, or in a print medium supply tray of the printing device, to determine the size of the print medium in the printing device. The supply of print medium and the resonance chamber are positioned so that the print medium covers a portion of the resonance chamber. An audio signal system then emits an audio signal to drive the resonance chamber. The frequency of the audio signal is varied until the natural resonance frequency of the chamber, as partially covered by the print medium, is discovered. The resonance frequency of the chamber will correspond to the amount of the chamber that is covered by the print medium and, hence, to the length (or width) of the print medium. In this way, the size of the print medium, whether standard or custom, can be determined.

Abstract: A continuous measurement of the level of contents in a container is effected by a level measuring device functioning in accordance with the transit time principle by means of waves transmitted from a position located above the highest possible contents level onto the surface of the material in the container. A measuring circuit determines the contents level from the transit time of the useful echo reflected from the material surface. In addition, one or more limit sensors are located at the container, each of which furnishes a signal indicating whether the contents level is above or below a level to be monitored by the limit sensor and which is situated between the minimum and maximum contents levels of the container. The measuring circuit receives the output signals of all limit sensors and uses these output signals to check and eventually to correct the contents level measured value determined by the level measuring device.

Abstract: Apparatus 1 for detecting a change of flow rate of a fluid being pumped through a pipe 2, the apparatus 1 comprises a cylindrical chamber 4, a fluid sensor 6 disposed on the side of the chamber 4, alarm means 8 and a vent valve 10 located at a distal enclosed end of the chamber 4. The chamber 4 extends upwardly from the pipe 2 and is formed with a port 4 at the lowermost end of the chamber 4. The lower end of the chamber 4 is formed with a port 7 that extends through the wall of the pipe 2 such that the inner region of the chamber 4 is in fluid communication with the pipe 2 via the port 7. The fluid sensor 6 may be a solid state liquid level switch such as an optical liquid level switch. It will be appreciated that other types of fluid level sensors may be used. The fluid sensor 6 is in communication with the alarm means.

Abstract: An air in-line sensor for detecting air bubbles in a therapeutic solution flowing through a tube utilizes a unitary type sensor having a channel for receiving the tube. The channel has a tube loading section. A signal emitting member is positioned on one side of the tube and a signal receiving member is positioned on an opposite side of the tube. A first air baffle is positioned between the signal emitting and signal receiving members.

Abstract: Acoustic level sensing by creating, or failing to create, resonance in a tube having a free end. An acoustic transducer at one end of the tube injects sound at a frequency that could produce resonance, depending on whether the free end is open or closed. The drive to the acoustic transducer is then removed, and the sound decay in the tube is monitored to determine if resonance occurred. Based on that determination, a signal is produced that indicates whether a material has or has not closed the free end of the tube. Beneficially, the same acoustic transducer that produces the sound monitors the sound decay. To determine whether resonance has occurred, or to verify system operation, the sound decay at the possible resonant frequency can be compared to the decay at another frequency. Temperature compensation can be performed by attempting to produce resonance at a plurality of frequencies.

Abstract: Resonant decay sensors that determine a parameter based on the decay of acoustic standing waves in a tube. Parameters that can be determined include temperature, pressure, the level of a material in the tube, and the height of a material above an end of the tube. Resonant decay sensors can produce both point level and continuous level sensors. A vibration mount, such as a rubber ring, beneficially isolates an acoustic transducer from the body of the tube.

Abstract: A method of measuring level in a vessel by means of a level measuring device operating with pulses is disclosed. Based on waves being transmitted into the vessel and reflected from the contents of the vessel a digital sampling sequence, representative of the amplitudes of said waves, is generated and a transit time difference, representative of said measuring level, is determined. For determining said difference a first data tuple, representative of a reference point in said envelope signal and a second data tuple, representative of an echo pulse in said envelope signal, are derived from the sampling sequence, each of said data tupel having an amplitude value and a time value.

Abstract: The present invention involves a system and method for detecting a graffiti-making act such as the spray of a spray paint can, the writing with a felt-marker pen on a surface, and the scratching with an abrasive instrument on a surface. The system includes one or more sensors adapted to sense the graffiti-making act and transmit a signal representative of the graffiti-making act, and a base unit including electronics adapted to process the signal and determined whether the signal represents a graffiti-making act, and a communication device coupled to the electronics and adapted to communicate to one or more entities that a graffiti-making act has been detected. The method includes sonically detecting the graffiti-making act, and initiating an alarm indicating that the graffiti-making act took place.

Abstract: The present invention involves a system and method for detecting a firearm shot. The system includes one or more sensors adapted to sense the firearm shot and transmit a signal representative of the firearm shot, and a base unit including electronics adapted to process the signal and determined whether the signal represents a firearm shot, and a communication device coupled to the electronics and adapted to communicate to one or more entities that a firearm shot has been detected. The method includes sonically detecting the firearm shot, and initiating an alarm indicating that the firearm shot took place.

Abstract: An assembly for monitoring a predetermined level of a material in a container comprises two ultrasonic transducers mounted on the container in line with the level to be monitored, such that an interspace exists between the ultrasonic transducers into which the material enters on attaining the level to be monitored. The one ultrasonic transducer is an emitter transducer which at predetermined points in time for emitting ultrasonic pulses is energized by a frequency which is so low that the ultrasonic pulses are transmitted through the interspace to the detector transducer even when the interspace is filled with air. The other ultrasonic transducer is a detector transducer which converts detected ultrasonic pulses into electrical detection signals.

Abstract: A portable container level indicator comprises a frame having an upper end and a lower end, and adapted to move along a generally vertical wall surface; an elongate handle having a frame end and a grip end, the frame end pivotally attached to the frame such that the angle between the frame and the handle may vary; a tapping mechanism attached to the frame and operable to propel a tapping member towards the wall surface such that the tapping member contacts the wall surface and generates a sound; and a trigger located adjacent to the grip end of the handle for operating the tapping mechanism. The sound is audible to the operator and may be amplified if necessary.

Abstract: An apparatus for establishing and/or monitoring a predetermined filling level in a container is described, which apparatus can be used in a wide range of applications, that is to say in many different media, which apparatus comprises: a housing (1), an oscillating element for projecting into the container, a diaphragm (5), which is fixedly clamped into the housing (1) at its edge and to which the oscillating element is fastened, and an electromechanical transducer for exciting the diaphragm (5) to produce oscillations in dependence on a transmission signal (S) present at the transducer and for receiving and converting oscillations thereof into an electrical reception signal (E), in which a percentage interval between a resonant frequency fr and an antiresonant frequency far divided by the resonant frequency fr exceeds 20% when the oscillating element oscillates in air.

Abstract: A non-invasive elastic wave fluid level sensing system for use in sludge laden environments, including transmitting and receiving transducers mounted on an outer face of a wall of a container for a fluid and along a propagation path for an elastic wave transmitted through the wall of the container wherein the elastic wave has a frequency of less than 5 kHz, more preferably less than about 2 kHz, and most preferably less than 1 kHz. A signal processor determines a change in a characteristic of the elastic wave between when a fluid is present in the container in the region of the propagation path and when a fluid is not present in the container in the region of the propagation path. One embodiment utilizes multiple horizontally oriented transmitting and receiving transducer pairs to detect levels of the fluid in the container.

Abstract: A wireless fuel gauge assembly including a fuel tank containing fuel having a level defining a liquid-air boundary. A control determines a digital indication of the fuel level. The control is able to determine plural digital signals that provide incremental level readings. A transmitter then sends an RF signal indicative of the level. A receiver captures the RF signal and communicates to a fuel gauge.

Abstract: The Automatic Shutoff Overflow Controller comprises a circuit which engages between a source of power and a water processing device, the controller, sensing an undesirably high water level in the device, shutting off the device and producing an audible warning that such condition exists.

Abstract: An arrangement for establishing and/or monitoring a predetermined filling level is described, in which a fixed phase difference (.DELTA..phi..sub.R), which is independent of the oscillation quality of the arrangement, exists between a transmission signal and a reception signal (E) at the resonant frequency of the mechanical oscillatory structure. This arrangement comprises a mechanical oscillatory structure (1) at least one transmitter (3), which excites the oscillatory structure (1) to produce oscillations, and two piezoelectric elements as receivers (24a, 24b). In accordance with a first variant, a first signal line (241a) of the first receiver (24a) is connected to an electrode which is arranged on a surface which bounds the first receiver (24a) in a direction opposite to its polarization. A second signal line (241b) of the second receiver (24b) is connected to the transmission signal line (5) via an electrical impedance (Z).

Abstract: Sensing the level of a liquid in a vessel by the pulse transit time technique is done by means of an ultrasonic transducer mounted above the highest-permissible level in the vessel which emits ultrasonic transmission pulses to the surface of the liquid and receives the ultrasonic echo pulses reflected from the liquid surface. The level in the vessel is established from the transit time of the ultrasonic pulses. To detect an overfill when the ultrasonic transducer is immersed in the liquid the decaying output signal of the ultrasonic transducer generated by the ringing of the ultrasonic transducer following the end of the each ultrasonic transmission pulse is analyzed. In this arrangement the fact is exploited that due to the better coupling of the ultrasonic transducer to the liquid than to air the ringing duration is shorter when the ultrasonic transducer is covered by the liquid.

Abstract: An apparatus for establishing and/or monitoring a predetermined filling level in a container is described, in which a fixed phase difference (.DELTA..phi..sub.R), which is independent of the oscillation quality of the apparatus, exists between a transmission signal and a reception signal (E) at the resonant frequency (f.sub.r) of the mechanical oscillatory structure. This apparatus comprises a mechanical oscillatory structure (1), an electromechanical transducer (2) having at least one transmitter (23) and a receiver (24), an evaluation unit (9), which determines the frequency of the reception signal (E), compares it with a reference frequency (f.sub.R) and generates an output signal which indicates that the mechanical oscillatory structure (1) is covered by a charge material if the frequency has a value which is less than the reference frequency (f.sub.

Abstract: Noninvasive method for determining the liquid level and density inside of a container having arbitrary dimension and shape. By generating a flexural acoustic wave in the container shell and measuring the phase difference of the detected flexural wave from that of the originally generated wave a small distance from the generated wave, while moving the generation and detection means through the liquid/vapor interface, this interface can be detected. Both the wave generation and wave detection may be achieved by transducers on the surface of the container. A change in the phase difference over the outer surface of the vessel signifies that a liquid/vapor interface has been crossed, while the magnitude of the phase difference can be related to fluid density immediately opposite the measurement position on the surface of the vessel.

Abstract: A continuous measurement of the level of contents in a container is effected by a level measuring device functionong in accordance with the transit time principle by means of waves transmitted from a position located above the highest possible contents level onto the surface of the material in the container. A measuring circuit determines the contents level from the transit time of the useful echo reflected from the material surface. In addition, one or more limit sensors are located at the container, each of which furnishes a signal indicating whether the contents level is above or below a level to be monitored by the limit sensor and which is situated between the minimum and maximum contents levels of the container. The measuring circuit receives the output signals of all limit sensors and uses these output signals to check and eventually to correct the contents level measured value determined by the level measuring device.

Abstract: A water level detecting and alarm system for informing a user when a water level within a bathtub has risen to or above a desired level. The system includes a housing having an opening at one end forming a lower lumen and a closed end opposite thereof. A securing means is attached to a side of the housing for adjustably securing to an interior surface of the bathtub corresponding to desirable water level. A partition within the housing is oriented traverse to a longitudinal axis of the housing. A tube projects in and through the partition coaxial with the longitudinal axis of the housing. A shaft has a flanged end and a lower end, and slidably projects through the tube. A float slidably projecting in the lower lumen of the housing for having a latitude similar to the water level within the bathtub. The float is secured to the lower end of the shaft for elevating and descending the shaft in a manner corresponding to the water level.

Abstract: An apparatus for establishing and/or monitoring a pre-determined filling level in a container is provided, in which the reception signal (E) corresponds to the desired measurement signal and in which a fixed phase difference (.DELTA..phi..sub.R), which is independent of the oscillation quality of the apparatus, exists between the transmission signal and the reception signal (E) at the resonant frequency (f.sub.r) of the mechanical oscillatory structure (1).

Abstract: An apparatus for establishing and/or monitoring a predetermined filling level in a container is provided, in which a reception signal (E) is equal to the measurement signal, and in which a fixed phase difference (.DELTA..phi..sub.R), which is independent of the oscillation quality of the apparatus, exists between a first transmission signal (S.sub.1), and a reception signal (E) at a resonant frequency (f.sub.r).

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. So that the piezoelectric element for given dimensions can be operated in a large frequency range, and so that a good adaptation to the diaphragm is achieved, the piezoelectric element consists of a porous piezoelectric ceramic having a type 3--3 connectivity.

Abstract: A sonic transducer shroud is shaped to present an inclined surface to rising bubbles and other matter during water treatment. Attached to the face of the sonic transducer, the shroud prevents the bubbles and other matter from being trapped on the transducer measurement surface and subsequently interfering with echo reception. The shroud has acoustic properties that are matched to the water such that the shroud is substantially acoustically transparent.

Abstract: A wireless interface probe having a transmitter, a signal transport/measuring device, and a receiver as provided. The transmitter has two sensors: a liquid level sensor and a water level sensor. The liquid level sensor determines the boundary between gaseous and liquid media. The water level sensor detects the presence of conductive liquid such as water. Signals generated by the transmitter sensors are transported inductively to the receiver via the signal transport/measuring device. The signal transport/measuring device is a standard metallic measuring tape which affixes to the transmitter via metallic fasteners. The receiver decodes the signals generated by the transmitter and creates an audio and visual reading output. The output reading indicates to the operator the level of the free-phase hydrocarbons and the level of the water. The difference between the two levels is the thickness of the hydrocarbons, which can be determined by using the measuring tape.

Abstract: A description is given of a sturdy device for establishing and/or monitoring a predetermined filling level in a container, which device exhibits a housing (1), two oscillating rods (3, 4) projecting into the container, a first diaphragm (2) which is fixedly clamped, at its border, into the housing (1), a second diaphragm (6, 6') which is arranged parallel to said first diaphragm in the interior of the housing (1), a piezoelectric element (7, 7') which is arranged on the second diaphragm (6, 6') and is intended for receiving and converting oscillations into an electric output signal and for inducing bending oscillations in the second diaphragm (6, 6'), and in the case of which device the mode of oscillation produced by the piezoelectric element (7, 7') corresponds to the mode of oscillation utilized for inducing oscillation in the oscillating rods (3, 4).

Abstract: A method and device for ultrasonic ranging. As in prior art devices, ultrasound pulses are transmitted by the device towards a target, and echo pulses from the target are received. The timing of the maximum of the amplitude envelope of the echo pulses is picked and used as a measure of the return time of these pulses. This maximum envelope time is relatively independent of the speed of sound between the device and the target. Preferably, the duration of the echo pulses is less than the response time of the receiving circuit, to enable an accurate pick of the amplitude envelope maximum.

Abstract: For monitoring a predetermined level of a liquid in a container an ultrasonic sensor is fitted on the outer surface of the container wall at a measurement point situated at the height of the level to be monitored, said sensor containing an ultrasonic transducer having a diaphragm in contact with the container wall. The components of the ultrasonic sensor including those of the ultrasonic transducer are grouped together in a sensor block which is releasably connected to an adapter secured to the container wall, this adapter being configured so that it can be secured in any way required to containers of differing shape and/or material.

Abstract: A high reliability instrument system includes means for applying a test condition to the instrument and for determining whether the instrument properly responds to the test condition, and means for inhibiting the generation of an instrument output in response to such testing. This provides verification that most of the instrument system components, but not the system output, are properly functioning. The system further includes means for overriding the output-inhibiting function when it is desired to test the entire instrument system including the system output. The instrument system may include a gap-type ultrasonic instrument, with the test condition comprising a pulse applied to one crystal, the effects of which are detected at the other crystal to determine sensor integrity. The system is preferably configured as a two-wire on-off instrument system, in which application of the test condition at a transmitter is controlled by signals applied to the two-wire signal loop at a remote receiver.

Abstract: A system for dissipating heat from a power supply enclosed within a housing having an air inlet and outlet. The system includes fans disposed in a plenum structure adapted to fit over the housing to thereby establish air communication between the fans and the housing inlet so that operation of the fans causes air to flow through the inlet, the power supply, and out through the outlet, thereby dissipating heat from the power supply. Each fan is operable independent of any other of the fans. The relationship between the fans may be serial, parallel, or a combination of serial and parallel. The fans are monitored to detect failure of any of the fans and, upon such detection, an alert is activated.

Abstract: The device for determining and/or monitoring a predetermined level of contents in a container comprises a sensor, which is so mounted on the container at the level of contents to be monitored that it comes into contact with the contents of the container when the same reach the predetermined level. The sensor is excited to mechanical vibrations at its natural resonant frequency by an exciting arrangement. An evaluating circuit serves for causing indicating and/or switching operations in a manner dependent on whether the frequency of the mechanical vibrations of the sensor is higher or lower than a switching frequency. Associated with the sensor is an electrical circuit element which has a characteristic parameter, whose value bears an unambiguous relationship to the natural resonant frequency of the sensor. In the evaluating circuit the switching frequency is set in accordance with the value of the characteristic parameter of the electrical circuit element.