Abstract: A fail-safe fluid transfer control apparatus has full redundancy in the response to various inputs such as overfill probe signals, ground detection signals, and the like. Independent microprocessor controllers independently evaluate the inputs and each output control signals to close a respective relay when the inputs indicate that fluid transfer may commence. The relays are arranged in series such that both must be closed for a fluid transfer to commence. The control signals from each controller include a static signal and an alternating signal, both of which must be properly output to close its respective relay. Each controller monitors the state of each relay, and discontinues its control signals if either relay appears to be malfunctioning. Each controller runs an different, independently written firmware program to process the detected inputs to prevent a common firmware error.

Abstract: The maximum full level is determined in a fuel tank of undetermined size using a fuel level sender referenced to the tank bottom. A minimum full value is selected for a given type of tank and when the sender signal goes below a percentage of that value and subsequently goes above the minimum full value, a fueling event is recognized and the current fuel sender value is adopted as the maximum full value. Where a heavily filtered signal is used to minimize the effects of fuel slosh, the maximum full value is subject to increasing to higher values occurring during a short period after fueling to allow recovery of the filtered signal. An empty value is calibrated before the vehicle is initially fueled. A maximum empty level is initially set and if a lower level is measured when the ignition is turned on, the lower level is set as the empty value. This calibration is terminated when the tank is fueled above the minimum full value.

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: Free space within a chamber is filled with a flowable material via an opening in a surface of the chamber. A delivery force is used to deliver the flowable material into the chamber via the opening. An outwardly directed force, independent of the delivery force, is applied to draw the flowable material away from the opening. The extent to which the free space within the chamber has been filled is sensed. And the delivering of the flowable material is controlled in response to the sensing. A wall of the chamber defines a longer dimension and a shorter dimension and the opening is in a portion of the wall that defines the longer dimension. The flowable material is delivered into the chamber via the opening in a manner such that, as the flowable material fills the chamber, a surface of the flowable material moves toward the opening along the longer dimension of the chamber.

Abstract: Free space within a chamber is filled with a flowable material via an opening in a surface of the chamber. A delivery force is used to deliver the flowable material into the chamber via the opening. An outwardly directed force, independent of the delivery force, is applied to draw the flowable material away from the opening. The extent to which the free space within the chamber has been filled is sensed. And the delivering of the flowable material is controlled in response to the sensing. A wall of the chamber defines a longer dimension and a shorter dimension and the opening is in a portion of the wall that defines the longer dimension. The flowable material is delivered into the chamber via the opening in a manner such that, as the flowable material fills the chamber, a surface of the flowable material moves toward the opening along the longer dimension of the chamber.

Abstract: A liquid level detecting system for detecting a conducting liquid level in a non conductive container which utilizes a grounding rod mounted in a lower portion of the container and a conductive sensing rod mounted at a position above the grounding rod. An oscillator is provided having a frequency in the range of about 600 hertz to about 100 kilohertz. The output of the oscillator is applied to the sensing rod through a high impedance circuit and a high pass filter. In another embodiment, the high pass filter may have the higher end frequencies attenuated to produce a band pass filter which selectively passes the frequency of the oscillator. The voltage drop across the circuit which includes the conductive sensing rod to ground is detected by a voltage peak detector and a threshold detector to produce an output which detects the drops in voltage when the conductive fluid level in the tank rises so that both the sensing rod and the grounding rod are covered, completing the circuit.

Abstract: Time-domain reflectometry based measuring systems which include transmission lines having an inner conductor and a ground conductor, a pulse generator generating pulses on the transmission line, and a pulse circuit producing oscillation pulses from pulse reflections caused by disturbances, such as a material interface, within the transmission line. The oscillation pulses induce subsequent transmission line pulses, beneficially using sing-around. A peak detector detecting the peak amplitude of the reflections and producing a trip-point voltage for the pulse circuit may be included. Transmission lines having a wound inner conductor and one or more switched taps which are selectively shorted to the ground conductor may be used. The system oscillates with pulses at frequencies which depend upon the state of the switches. Those frequencies (or periods) can be resolved into a parameter which depends upon the position of a transmission line disturbance.

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.

Abstract: Methods and systems for displaying a level of a liquid contained in a tank are disclosed, wherein the level of the liquid is measured using a sensing device. An embodiment of a system includes a user interface, a processor, and a display. The user interface allows a plurality of parameters, including a lower display level and an upper display level, to be modified. The processor communicates with the sensing device and the user interface to scale the level in dependence upon the lower display level and the upper display level. The display communicates with the processor to graphically display the level of the liquid scaled in dependence upon the lower display level and the upper display level.

Abstract: Provided is a self-calibrating system which self-calibrates for operation regardless of the particular reservoir or expansion tank, which further detects when a hydraulic fluid system adapted to a turf care machine has developed a leak and which warns the machine operator of such a leak before an appreciable amount of hydraulic fluid is allowed to leak from the system. The system includes a reservoir for holding a quantity of hydraulic fluid. The reservoir is connected via a connecting tube or hose located at the upper-most portion of the reservoir and connected to an expansion tank mounted substantially adjacent to the reservoir. The expansion tank includes a fitting having an elongated tube extending down into the expansion tank. The end of this tube is maintained substantially below the level of hydraulic fluid in the expansion tank during operation of the turf care machine to which it is attached.

Abstract: Abnormal flow of liquid in a non-pressurized conduit such as a drain line of a building is detected by a liquid level sensor unit connected at a conduit location not anticipated to fill with liquid during normal flow, so that liquid backing up at such location will enter a sensor chamber of the unit to cause a liquid level sensor to signal an indicator. A monitoring system uses at least one such sensor to signal at least one local or remote indicator that indicates which sensor has detected abnormal flow. The system can monitor for short times particular drain lines suspected of experiencing abnormal flow, or can serve on a long-term basis to provide an early warning of clogging and blockage in lines selected for monitoring.

Abstract: The invention relates to a method of measuring the quantity of fuel in a tank of a space vehicle. It includes a step of measuring the level of fuel in the tank during at least one acceleration stage of the space vehicle. The level of fuel can be measured by detecting the level of fuel in a tube having a first end in communication with a first region of the tank which constitutes a bottom of the tank relative to an acceleration direction, and having a second end in communication with a second region of the tank that is spaced apart from the first region.

Abstract: A fluid level detector for determining the level of fluids in motor vehicle components such as engines and transmissions includes a cylinder mounted in parallel to the surface of the fluid. The cylinder has a diameter which spans the fluid range to be monitored and includes a first, open end and a second closed end. A piston is disposed within the cylinder and is biased towards the first end where fluid is admitted to the cylinder interior and can be moved towards the second end under the influence of an actuator. When moved, the openings in the cylinder are blocked by the piston to thereby trap the fluid in the cylinder. As the piston continues to move towards the closed end of the cylinder, air above the fluid surface is exhausted through an orifice. Once the air is exhausted from the cylinder, fluid exits the orifice resulting in an increase in operator effort required to move the piston.

Abstract: An automatic photographic developing apparatus for photosensitive materials includes a number of processing baths which are filled with processing solutions of different types for processing silver halide coated photosensitive materials. A same number of solution tanks communicated with the respective processing baths are provided for supplying the processing solutions, produced by dissolving solid agents, to the respective processing baths. A level sensor is installed in each of the solution tanks which monitors the level of the processing solution in the respective solution tanks. A plurality of shield members are provided, each shield member surrounding and protecting a respective one of the level sensors, and each shield member being detachably mounted to its respective level sensor. Each of the shield members includes a plurality of split members which are separable from each other and which are connectable to each other to surround the respective level sensor.

Abstract: A level transmitter for use in a process application measures height of a product in a tank. The level transmitter includes a microwave antenna directed into the tank. A low power microwave source sends a microwave signal through the microwave antenna. A low power microwave receiver receives a reflected microwave signal. Measurement circuitry coupled to the source and receiver initiates transmitting of the microwave signal and determines product height based upon the received, reflected signal. Output circuitry coupled to a two-wire process control loop transmits information related to product height over the loop. Power supply circuitry in the level transmitter coupled to the two-wire process control loop receives power from the loop which powers the level transmitter including the microwave source and the microwave receiver.

Abstract: A fluid leak detector mechanism having a main fluid tank, an expansion tank for receiving fluid therefrom as the fluid becomes heated and expands, and a sensing chamber operatively coupled with the main tank. A signalling mechanism signals to an operator when the level of fluid in the sensing chamber has dropped significantly to alert the operator of the presence of a leak. An oil return valve is operatively coupled between the main tank and the expansion tank and has an open position that allows fluid to flow back to the main tank from the expansion tank and a closed position that blocks oil from flowing from the expansion tank to the main tank. A temperature sensor senses the temperature of fluid. A control mechanism shifts the oil return valve to its open position when the temperature sensor detects a significant drop in fluid temperature, thereby allowing the fluid levels to be reset with changes in fluid temperature.

Abstract: The liquid level sensor comprises a graduated tape or cable whose free end is fixed to a plunger core that includes a housing and a probe for detecting the presence of a liquid. The probe comprises a metal waveguide having a cylindrical solid top portion, a portion of smaller section constituting a mechanical amplifier, a frustoconical portion, and a cylindrical bottom end portion constituting the sensitive portion of the probe. The metal waveguide is connected to the housing of the plunger core in sealed manner via a support flange which is fixed to the conical portion of the metal waveguide in such a manner that only the portion of the waveguide situated beneath the fixing zone emerges from the housing and can come into contact with a liquid. A transducer electrically powered by electronic processing circuits is disposed at the free end of the top portion and is excited at a predetermined frequency f.sub.i to create incident elastic waves in the waveguide.

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: A liquid level sensor device, particularly adapted for use with corrosive and hazardous liquids such as oil, for measuring the liquid level in a storage tank or vessel. A tubular device is placed vertically in a liquid storage tank and senses the liquid level by having a float embedded with magnets move vertically along the axis of reed switches encased in the tubular device. The device contains temperature sensors to measure the temperature of the tank fluid, and microprocessors that scan the reed switches, transmitting data through a connector in the device top to a nearby computer for recording and transmission to a control and monitoring location. The electrical data system inside the device utilizes only two conductive trace runs throughout the device length to maximize reliability while minimizing the copper used. Special mechanical and electrical assembly connectors inside the device permit the device to flex safely in turbulent liquid conditions, without breakage.

Abstract: A liquid level detecting system which utilizes audio frequency with components having sizes and values usually associated with RF frequencies, thereby providing the reliability and low cost of audio components with the small size typically associated with RF systems. A conductive element is mounted within a container, the conductive element is provided with an insulative coating. A large change in capacitance and capacitance reactance is produced when the insulated conductive element is immersed in a conductive liquid. The change in output of the audio oscillator, passed through the low pass network, which includes the capacitance of the conductive element is fed to an active detector. In one application, the detector is utilized to sense the level of water in a fuel/water separator and, in a second application, a pair of liquid level detectors are utilized to control the operation of a bilge pump.

Abstract: A liquid level monitoring system for underground storage tanks includes a submersible monitoring pipe system having telescoping sections that are biased to an extended position enabling the pipe to be self-retained within the tank between its upper and lower walls adjacent to and offset axially from a selected access opening in the tank, such as the discharge opening which normally accommodates the pump for the tank. The pipe system houses an electronic level sensor which is coupled to an above ground control system via conductor wires. An elongate accessing member having an openable and closable clamp jaw assembly for gripping the pipe system and disposing it in a compressed condition within the tank offset from the riser opening is provided as a part of the system.

Abstract: A microwave point level instrument is adapted to detect level or change of products in a storage vessel. The instrument includes a microwave transducer periodically developing a pulse of microwave energy. A microwave bridge is driven by the transducer for receiving pulses of microwave energy. The bridge includes a reference arm receiving a portion of each pulse of microwave energy to be altered by a variable impedance tuning circuit. A measurement arm receives another portion of each pulse of microwave energy to be altered by dielectric properties of a product at a process seal installed in a storage vessel, in use. A detector arm develops a microwave signal responsive to imbalance in the bridge between the microwave energy altered by the tuning circuit and the microwave energy altered by the dielectric properties of the product. A sensing circuit is coupled to the bridge detector arm for developing an electrical signal responsive to the microwave signal representing the imbalance.

Abstract: A tube is inserted into a first liquid layer, and an air bubble is generated at a tip opening of the tube. The tube is then moved toward a second liquid layer while retaining the air bubble, and a change in the internal pressure of the tube caused by the air bubble reaching the boundary between the first and second liquid layers is detected. After the tip opening of the tube is raised to the top surface of the first liquid layer, the first liquid is sucked up by the tube while the tube is moved to the position where the pressure change was detected.

Abstract: The present electronic multi-purpose material level sensor is based on time domain reflectometry (TDR) of very short electrical pulses. Pulses are propagated along a transmission line that is partially immersed in a liquid, powder, or other substance such as grain in a silo. The time difference of the reflections at the start of the transmission line and the air/liquid interface are used to determine levels to better than 0.01 inch. The sensor is essentially independent of circuit element and temperature variations, and can be mass produced at an extremely low price. The transmission line may be a Goubau line, microstrip, coaxial cable, twin lead, CPS or CPW, and may typically be a strip placed along the inside wall of a tank. The reflected pulses also contain information about strata within the liquid such as sludge-build-up at the bottom of an oil tank.

Abstract: The High Accuracy Electronic Material Level Sensor (electronic dipstick) is a sensor based on time domain reflectometry (TDR) of very short electrical pulses. Pulses are propagated along a transmission line or guide wire that is partially immersed in the material being measured; a launcher plate is positioned at the beginning of the guide wire. Reflected pulses are produced at the material interface due to the change in dielectric constant. The time difference of the reflections at the launcher plate and at the material interface are used to determine the material level.

Abstract: A fuel gauging system for use in determining the level of fuel in a tank. The system incorporates a resonant circuit for measuring the resonant frequency of at least one probe immersed in the fuel located in the tank. From measurements of variations of the frequency of resonance, the level of liquid in the tank is determined, and the fuel quantity is then calculated and displayed.

Abstract: A liquid level monitoring system for underground storage tanks includes a submersible monitoring pipe having telescoping sections that are spring biased to an extended position enabling the pipe to be self-mounted within the tank between its upper and lower walls adjacent to and offset axially from a selected axis opening in the tank, such as the discharge opening which normally accommodates the pump for the tank. The pipe houses an electronic level sensor which is coupled to an above ground control system via conductor wires. A tank adapter is secured to the tank opening and provided with a passage through which the conductor wires extend for routing out of the tank without interfering with the clearance normally provided for insertion and removal of the pump.

Abstract: To measure the level of contents in metallic tanks by means of short electromagnetic waves, it is proposed to mount the complete level measuring assembly, including the horn antenna, outside the tank. The transmitted waves are projected through an opening in the tank wall toward the surface of the medium whose level is to be measured. The opening is closed with a glass or ceramic plate. To distinguish the useful signal within the unwanted echos caused by multiple reflections of the electromagnetic waves at the glass or ceramic plate, a damping layer of a conventional damping material is interposed between the microwave coupling element and the surface of the glass or ceramic plate. To achieve an optimum signal-to-noise ratio, the damping coefficient is fixable and the distance between the level measuring assembly and the surface of the glass or ceramic plate is adjustable in the axial direction of the opening.

Abstract: A method for determining the level of a first layer of liquified material submerged below a second layer of liquified material is disclosed. A tube having first and second opposing tube ends includes a sacrificial cap covering the first tube end. The tube is adapted for insertion of the first tube end through the second layer into the first layer. The cap is adapted to substantially disintegrate after insertion into the first layer, such that pressure pushes a portion of the first material into the tube to a level substantially equal to the level of the first layer. A sensor determines the level of the measured portion in the tube.

Abstract: A system for generating three-dimensional objects by creating a cross-sectional pattern of the object to be formed at a selected surface of a fluid medium capable of altering its physical state in response to appropriate synergistic stimulation by impinging radiation, particle bombardment or chemical reaction, successive adjacent laminae, representing corresponding successive adjacent cross-sections of the object, being automatically formed and integrated together to provide a step-wise laminar buildup of the desired object, whereby a three-dimensional object is formed and drawn from a substantially planar surface of the fluid medium during the forming process.

Abstract: A fluid level sensing system, particularly for sensing the water level in a steam generating boiler, comprises a vessel connected to the boiler so as to contain water and steam at substantially the same level as in the boiler, a number of vertically spaced electrodes projecting into the vessel, and circuitry for measuring the electrical impedance sensed by each electrode. The circuitry, which can be multiplexed to each electrode in turn, includes a first comparator for producing an output when the sensed impedance lies between the normal maximum impedance of the water and the normal minimum impedance of the steam above the water, this output being demultiplexed to drive a vertical display to show the level of the steam/water interface. The circuitry additionally includes a second comparator for producing a further output when the sensed impedance lies below the normal minimum impedance of the water, which further output is indicative of a variety of different fault conditions and drives a fault indicator.

Abstract: A system for providing an indicator light operated by a fluid level sensor, including a power source providing the voltage to a first node, a first LED and a first circuit branch connecting the first node to ground, a voltage dropping component in the first circuit branch, a second circuit branch including a second LED connected to the first node in parallel with the first LED, and a normally open first fluid level switch that can close to connect the second circuit branch to ground. The sum of the turn on voltage of the first LED and the voltage drop across the voltage dropping component when the first LED is on is greater than the voltage drop from the first node to ground through the second LED when the first switch is closed, so that the first LED is normally on when the first switch is open, and the second LED is on and the first LED is off when the first switch is closed.

Abstract: A hydraulic fluid lead detection system which self-calibrates for operation regardless of the particular reservoir or expansion tank. A reservoir stores a quantity of hydraulic fluid and is connected via a connecting tube or hose located at the upper-most portion of the reservoir and connected to an expansion tank mounted substantially adjacent to the reservoir. An elongated tube extends down into the expansion tank. The end of this tube is maintained substantially below the level of hydraulic fluid in the expansion tank during operation of the turf care machine. During operation, the hydraulic fluid expands with rising temperatures, and the connecting tube communicates the expanding fluid to the expansion tank. A float type fluid level sensor measures the level of hydraulic fluid within the expansion tank and outputs an electronic signal corresponding to the fluid level in the expansion tank to the microcomputer based monitoring unit, which also senses the fluid temperature.

Abstract: A leakage detection system is provided having a plurality of locally distributed integrated units with a leakage sensor, preprocessing unit, and evaluation unit which connects with the individual integrated units or with a group of integrated units via a serial bus line. In each preprocessing unit, the value measured by the leakage sensor is subjected to a temperature compensation process.

Abstract: A system for monitoring the water level of a pressure drum having a pressure column comprises a plurality of electrodes communicating with the column for contacting water and steam within the column. Each electrode has its own location and produces a first output which corresponds to the presence of water or a second output which corresponds to the presence of steam. A discriminator is operatively connected to the electrodes; and the discriminator has an analog-to-digital converter for receiving the output of each electrode and converting the output to a digital signal which represents the water conductivity for each electrode. A central processor is operatively connected to the discriminator for powering the discriminator as well as for receiving the digital signals in order to determine a slope degradation between the conductivity and the location of each electrode in the column. The central processor also determines an inflection point between the water and the steam in the column.

Abstract: An automatic system is disclosed which monitors and replenishes hazardous liquids in their holding tanks, as such liquids are typically used in manufacturing processes. The inventive system and method obviate the need for manual surveillance and handling of the hazardous liquids during the detection and replenishment maintenance tasks. In prior practice, maintenance personnel were subjected to dangers from the hazardous liquids and their noxious gases, while the work area (e.g., clean room) in the vicinity of the liquid tanks was also subjected to contamination.

Abstract: An overfill prevention device for storage tanks includes an elongate tubular housing having a liquid flow passageway. A normally open main valve and a normally closed vapor retaining bleed valve are associated with the fluid passageway. Closure of the main valve interrupts the primary flow of liquid through the passageway and closure of the bleed valve prevents any further liquid from entering the tank and also prevents the escape of vapors from the tank. Operation of the main valve is controlled in significant part by a valve latch assembly which is carried by the housing and a relatch assembly which is carried by the main valve. The relatch assembly ensures operative engagement of the main valve with the valve latch assembly upon movement of the main valve from the intermediate position to the open position. Operation of the main valve and vapor retaining bleed valve is also controlled indirectly by a plurality of floats which are maintained in a float chamber extending adjacent the liquid passageway.

Abstract: A sensor for determining both the presence of a liquid in a container or conduit, and identifying its type has a sensor housing body containing both a pair of piezoelectric elements used as the transmitter and receiver of ultrasonic waves directed across a gap therebetween in an ultrasonic liquid presence detecting circuit and a pair of electrodes exposed to any of such liquid in the gap used in a circuit for identifying the liquid type. The liquid identification circuit is either of the capacitance type, which produces a variable amplitude output signal depending on the type of liquid in the gap between the two electrodes, or operates to measure the difference in response time between pulses applied to each of the electrodes with one serving as a reference.

Abstract: A fluid overfill and identification system uses a pulsed signal to both detect an overfill condition and identify a fluid product contained in a compartment. The pulsed signal is converted into an optical pulsed signal which is used with a retroreflective prism to detect when a fluid in the compartment has reached a desired capacity. Encoded in the pulse width of the same pulsed signal is the specific fluid product located in the compartment. Furthermore, different pulse frequencies are provided depending on whether the tanker truck is at a service station or at a loading terminal, thus allowing the system to distinguish between the two. At a marketing terminal, a new code is loaded into the system as a new fluid product is loaded into a compartment. A residue sensor may detect residual fluid in the compartment, and prevent the loading of a new fluid product and a new ID code.

Abstract: A method for determining the volume a substance having a density level in vertical storage tanks. This method uses a strain gauge that is attached to the exterior of the side wall of a tank. As the volume of the substance fluctuates in the tank, the walls are acted upon by the weight of the substance. The greater the volume of a substance, the greater the force pushing on the tank walls and vice-versa. This force causes the walls to deform slightly. This deformation can be measured by the strain gauge mounted on the tank wall. Because this deformation is directly related to the volume of the substance being stored in the tank, the deformation read by the strain gauge can be translated into its volume by calibrating the gauge measurements with known volumes in the tank.

Abstract: The present invention resides in a probe excitation and testing ("PET") system that can apply either a normal excitation or a "small" bias test excitation to overfill protection probes mounted within storage and transport tanks used to store, e.g., flammable fluids. The PET system applies the normal excitation for normal operation of the probes to provide overfill protection, and applies a "small" bias test excitation to the probes for performing diagnostic tests, including anti-cheating. The PET system can also perform a probe signature validation test under normal excitation to ascertain whether the probes are responding thereto in accordance with specifications relating to characteristic parameters of the probes' output waveforms, e.g., duty cycle, magnitude, and period.

Abstract: An apparatus has a liquid level sender providing a sender output signal which varies with a measure of a liquid and which varies with a slosh of the liquid. A main control circuit couples and decouples the sender output signal to a process circuit, the process circuit provides an output signal to a liquid level indicator. Two monitor circuits monitor the output of the process circuit and provide a control signal to the main control circuit if the sender output signal varies from the output of the process circuit by more than a predetermined amount. A switch within the main control circuit decouples the sender output signal from the process circuit in response to the control signal. Sample circuitry within the process circuit drives the output of the process circuit in accordance with a sampled signal when the sender out signal is decoupled from the process circuit.

Abstract: A method and apparatus for measuring scour depth in a waterway bed is described. The apparatus utilizes magnetic attraction between a weight resting on the waterway bed and a magnetic probe within a guide chamber to which the weight is attached. Magnetic attraction between the probe and the weight retains the probe in an aligned position with the weight, enabling a user to detect a reduced force in the support line to identify the location of the weight and thus the riverbed. In a second embodiment, the inventive device includes a second weight slidably attached to the guide enabling a measurement of infill in a waterway bed scour. In the method according to the invention, the weight is placed upon the waterway bed and allowed to rest there. A probe is then inserted into the chamber and allowed to descend to the level of the weight where magnetic attraction supports the probe.

Abstract: A system for inventory reconciliation and leak detection of particular utility in liquid storage tanks such as the terminal facilities that are used for the storage and distribution of gasoline. The system has the ability to monitor the inventory of several different liquid products on hand at such a facility, account for product deliveries and product dispensations (e.g., to tank trucks which deliver the product from the terminal facility to a gasoline service station), and to continually check the volume of each product dispensed against the inventory on hand so as to provide a real-time system for detecting leaks from the tanks containing each product, losses due to evaporation, volume discrepancies from flow meters which are out of calibration, and other irregularities.

Abstract: A method and apparatus for detecting fluid level in a tank in the vicinity of a transmission line (1), the fluid level being such as to cause reflection of a signal transmitted along the transmission line. The method includes the steps of:a) transmitting a signal along the transmission line;b) monitoring the transmission line for any reflections of the signal;c) generating an analysis window of time (t.sub.1, t.sub.2, t.sub.3) if the magnitude of a given characteristic of the reflected signal is greater than a predetermined threshold value; andd) analyzing the reflected signal received during the period of an analysis window to provide the required information on the fluid level.

Abstract: A bandwidth synthesized radar level measurement system includes a transceiver for generating a transmitted signal and a sweep signal. An antenna coupled to the transceiver sends the transmitted signal toward a level corresponding to a product surface and receives a reflected signal therefrom. A sweep generator generates a chirp slope signal in response to the reflected signal. An intermediate frequency (IF) processor receives the chirp slope signal and a difference signal mixed from the transmitted and reflected signals. The IF processor produces an amplified IF signal and a sweep control receives the amplified IF signal to adaptively control the sweep generator and to produce an output signal including a distance from the antenna to the level corresponding to the product surface.

Abstract: A fail safe output stage for a tank fluid level detection circuit having power supply/output leads periodically places a shunt across the leads to periodically generate a LOW signal which alternates with a HIGH signal to indicate an underfilled condition. In a filled condition, a steady signal appears across the leads. The output stage of the detection circuit consists of a parallel connection of switching devices where the "on" impedance of any single switching device is insufficient to place the detection circuit output lead in a LOW logic state. Therefore, in a condition where one of the switching devices fails, the detection circuit output may continue to alternate, but the alternating output is not recognized as such by a disable circuit which does not detect a LOW logic condition on the output lead. Accordingly, the failed output is interpreted as an filled condition, resulting in a shutdown of the system.

Abstract: An ink jet pen supply cartridge having a spring biased ink reservoir with a visual indication of remaining ink quantity. The reservoir tends to collapse laterally as the ink supply decreases due to differential pressure exerted thereto. The spring-reservoir is contained in a rigid cartridge and a pair of flexible tape members are cemented or welded, one to each side of the spring-reservoir, and extend generally parallel toward a narrow end surface of the cartridge at which they overlap and can be viewed through a window. The overlapping relationship of the tape members provide ink quantity indicia which change as the spring-reservoir collapse draws them past each other.

Abstract: Rotating beverage receptacle-filling equipment for filling receptacles has receptacle sites spaced along its periphery and metering containers which can be filled from a beverage tank. Beverage is discharged from the metering containers into the beverage receptacles. A control system recognizes upper and lower liquid levels in the metering containers to control the discharge volume. The metering containers are transparent and at least one stationary video camera observes the metering containers of several adjacent receptacle sites. An image analyzer continuously monitors the metering containers in the field of view of the camera while detecting the levels in different angular positions at the receptacle sites and generates control signals for valves at the receptacle sites. A camera observes the refill limit level to control a refill valve and a camera observes the discharge limit level to control a discharge valve.

Abstract: The disclosure is directed to a Lever oscillator for use in high resistance resonator applications, especially for use with quartz resonator sensors. The oscillator is designed to operate over a wide dynamic range of resonator resistance due to damping of the resonator in mediums such as liquids. An oscillator design is presented that allows both frequency and loss (R.sub.m) of the resonator to be determined over a wide dynamic range of resonator loss. The Lever oscillator uses negative feedback in a differential amplifier configuration to actively and variably divide (or leverage) the resonator impedance such that the oscillator can maintain the phase and gain of the loop over a wide range of resonator resistance.