Abstract: Apparatus for monitoring the depth of granular material in a container or on a carrier includes a unique probe tip and complementary apparatus, which includes a support, a positioning mechanism and a cleaner, to which the tip is fastened. The probe tip is comprised of an electrically conductive metallic strip having a metallic grid attached to one end and electrical connections at the opposite end for electrically connecting the strip to electronic equipment. The strip is enclosed in an electrically insulating sheath. A section of the sheath having a known surface area and thickness and contiguous with the metallic grid is filled with electrically conducting material. The ratio of the surface area of the section to its thickness is not less than about 20. The section has a thickness of not more than about 1.0 centimeter. The electrical resistivity of the section can be between about 0.1 and 10 megohms/cm.sup.2.

Abstract: Liquid level control system in which there is a basic resistive level sensing electrode or probe extending into a vessel or tank containing liquid. In addition there is a conductive guard ring or shield insulated from both the probe and from the conductive member or portion of the body of the vessel. The guard ring electrode acts as a current source to counteract electrical leakage across the surfaces between the probe and vessel body to minimize the effects of leakage and maintain the liquid level sensing control operative under most leakage conditions by balancing the leakage currents. In the event the leakage becomes excessive, a control is activated to signal the excessive leakage condition in a suitable manner.

Abstract: A low liquid level sensor in a hot water heating system permitting testing operability thereof in situ without draining down the system. The sensor is located in a cavity that has an opening in the bottom thereof in fluid communication with the liquid in the vessel during normal operation of the system. The end of the opening is at a lower elevation than the sensor and liquid from the vessel is in the cavity during normal operation of the system. When the liquid drops to a predetermined low level the sensor activates the safety cut-off. Valved passage means are provided exteriorly of the vessel so that a gas can be injected into the cavity to pressurize the same and drive the liquid in the cavity through the opening into the vessel simulating a low water level condition. At the simulated low water level condition operability of the sensor can be determined. Means are provided to release the gas from the cavity.

Abstract: A conductive multilevel liquid sensor uses conventional integrated circuits such as inverters and voltage comparators as signal detectors, and a flat cable having corrosion-resistant probe conductors of different lengths as the sensing probe assembly. The binary encoded outputs of the signal detectors identify the sensed liquid level. A continuous level control is realized by the addition of timing logic, and sensor operation range is improved by having the voltage at one comparator input be adaptive to the change in liquid conductivity.

Abstract: A length of metal sheathed metal oxide cable is perforated to permit liquid access to the insulation about a pair of conductors spaced close to one another. Changes in resistance across the conductors will be a function of liquid level, since the wetted insulation will have greater electrical conductivity than that of the dry insulation above the liquid elevation.

Abstract: An apparatus for measuring the level, volume or rate of flow of an electrically conductive fluid, such as water, includes a reference conductor connected to a reference potential and a plurality of additional, vertically spaced conductors affixed to an insulating surface. The reference conductor is normally placed at the lowest point of the liquid container whereas the other conductors are positioned within the liquid container at various points above the reference conductor. When the level of the liquid is above the position of one or more of the additional conductors, the liquid effects an electrical conduction path between the conductors below the liqid level and the reference conductor and thus with the reference potential. The conductors are connected through a logic circuit to a plurality of display elements, which are selectively actuated to provide an indication of the level of the liquid corresponding to the uppermost conductor covered by the liquid and thereby connected to the reference potential.

Abstract: A liquid level sensing circuitry using a conductive probe to sense and store an acceptable or unacceptable level signal. Any unacceptable level signal is stored a short time, determined by the circuitry, following termination of power to a power conductor. The circuitry provides a discernible indication of an unacceptable level when power is subsequently applied to the power conductor if an unacceptable level signal has been stored. A separate discernible signal is provided at such time if an acceptable level signal was stored.

Abstract: The present invention relates to a device for determining the level of the melt in a ladle or the like, which device comprises a lance (20) with a tubular end adapted to be submerged in the melt. At least one non-contact sensor (1) is mounted in the tubular end of the lance (20) straight opposite to an aperture (24) through the wall of the tubular end. The aperture (24) or the apertures are covered by a sleeve (27) of a heat resistant, electricly non-conducting material. The sensor or the sensors are electrically connected to operational equipment for signals coming from the sensor or the sensors.

Abstract: An improved bedwetting detection device is responsive to moisture in the bed of the user to create an alarm when bedwetting occurs. The device includes controlling circuitry connected to metallic conductors (12, 14) installed in the bed of the user. The circuitry periodically provides electrical pulses to the conductors (12, 14) so as to minimize the introduction of electrical impulses into the bed of the user. Furthermore, the pulse created by the circuitry is of a very low voltage so as to further minimize the amount of electrical energy introduced into the bed of the user.

Abstract: A liquid level presence detection circuit includes a selectively gatable TRIAC serially connected with a load and triggered into conduction by twin sensitive-gate SCR's connected anode-to-cathode with the gates of the SCR's connected to voltage divider circuits which provide gating current to the SCR's in response to the presence of a conductive liquid bridging the two spaced apart contacts of a liquid presence detecting probe. The circuit is used in wet-niche type lamp assemblies that provide underwater illumination in swimming pools and the like and in which cooling is effected by the surrounding liquid. The detection circuit advantageously interrupts the flow of electrical energy to the lamp when the level of surrounding liquid falls below a predetermined level to prevent over-temperature operation of the lamp and consequent damage thereto and resumes the flow of electrical energy to the lamp when the level of the surrounding liquid increases to a safe level to permit adequate cooling thereof.

Abstract: A device for detecting the presence of water in a fuel tank comprising a fitting mounted at the lower most portion of said tank having a water sensing alloy on said fitting. The fitting positions the water sensing alloy in the tank in the position where water will tend to collect. The fitting also includes a socket for connecting an indicating device such as an ammeter to determine the presence of water in the tank. The length by which the fitting extends into the tank can be used to determine the depth of water in the tank and when the amount of water collected at the bottom or sump of the tank exceeds a predetermined depth it will be detected by the indicator connected externally to the water sensing alloy. A useful water sensing alloy is comprised of a composition of lead, tin, and zinc each being present in an amount of between about 20-45% by weight, with the composition also containing small amounts of up to about 0.1% of copper and/or up to about 1% of either samarium, ruthenium, vanadium or selenium.

Abstract: A method is provided for measuring the heat influx of a cryogenic transfer system. A gaseous phase of the cryogen used during normal operation of the system is passed through the system. The gaseous cryogen at the inlet to the system is tempered to duplicate the normal operating temperature of the system inlet. The temperature and mass flow rate of the gaseous cryogen is measured at the outlet of the system, and the heat capacity of the cryogen is determined. The heat influx of the system is then determined from known thermodynamic relationships.

Abstract: An article transfer apparatus (10) is provided for transferring articles (16) from a predetermined first position to a varying second position and discharging the articles (16) at the second position. Difficulty is often encountered in controlling the drop height of articles (16) delivered by a conveyor (18) for random placement at varying levels in a container (12). It is desirable to minimize the drop height to prevent damage to the article (16). A carriage (36) on the article transfer apparatus (10) is controllably operated to controllably discharge articles (16) at a preselected distance above either the bottom of the container (12) or articles (16) predisposed within the container (12). The invention is particularly useful for transferring finished metal piston pins (16) from a conveyor (18) to a tote box (12).

Abstract: A device for determining the relative properties of stratified fluids, such as the interface between oil and water having plural fluid character recording stations with sensors on an elongated member. Means are provided to clear the recording stations to preclude contamination of the sensors by fluid from other strata.

Abstract: Apparatus for indicating the level of the electrolyte in a battery cell. A three-electrode sensor probe having the electrodes partially embedded in an electrically insulating housing suspended in the electrolyte so that a portion of the probe is immersed in the electrolyte. The electrolyte provides the only conduction path between the electrodes so that the resistance between the electrodes varies according to the level of the electrolyte. An AC or pulsed DC sensing signal is applied between two of the electrodes and an output signal related to the level of the electrolyte is produced. A polarizing current is applied to the other electrode to prevent the buildup of surface contamination on the two sensing electrodes due to the sensing signal.

Abstract: Apparatus for monitoring the level of a developing solution within a storage tank utilizing at least two electrodes having active surfaces exposed to the developing solution for the conduction of electrical current therebetween. The electrodes have their active surfaces positioned at different levels within the developing solution. One electrode serves as a reference and is always immersed in the developing solution. Electrical signals developed when the developing solution falls below the level of the active surface of the electrodes is utilized to trigger an electrical switching circuit which is connected to the electrodes for governing a signalling and/or control action of the developing station.

Abstract: A liquid level sensing apparatus includes a probe having a high positive temperature coefficient of resistivity. The probe is connected in a circuit including an operational amplifier and a series transistor which maintains the voltage across the probe constant for a fixed period following switching on of the apparatus and which produces a voltage signal related to the current flowing in the probe. This voltage signal is differentiated by a differentiating circuit to provide a signal indicating the rate of change of the voltage signal from which it is determined whether or not the probe is immersed in a cooling liquid. A warning lamp is actuated by a latching switch circuit when the probe is not immersed. A second example is described in which the probe current is maintained at a fixed level and the rate of change of the voltage across it is monitored.

Abstract: A fluid level indicator circuit is used in cooperation with a probe attached to a long wire where the probe has first and second electrodes for contacting the surface of the fluid and leads communicating to the indicator circuit. The water level indicator has a low current high gain transistor and a power source which has sufficient potential to not only properly reverse bias the transistor when the probes are out of contact with the fluid but also properly forward bias when the probes are in contact with conductive fluid. A meter and current adjusting device are provided in series with a collector and emitter to provide an indicator when the probes are in or out of the water. The circuit also has a light to give a visual indication.

Abstract: An apparatus for cooperation with an existing opening within a cooling radiator of a vehicle for determining the liquid level in the radiator. The radiator, which may be an automobile or truck radiator, is connected to an electrical power source of the vehicle through the vehicle chassis. An insulator is established relative to the vehicle radiator in a substantially fixed relation. A sensor is mounted to the insulator for extending into the liquid in the radiator when a sufficient quantity of liquid is contained therein. The sensor has a plurality of curved surfaces for increasing the surface area of the sensor. An indicator interconnects the sensor with the electrical power source of the vehicle for indicating the level of liquid contained in the radiator by conductivity through the liquid in contact with the sensor. The increased surface area of the sensor enables the indicator means to be a conventional incandescent lamp connected in series with the sensor and the electrical power source of the vehicle.

Abstract: The invention is a bi-level fluid level sensor intended to be used in the bilges of boats with complementary equipment which activates emergency equipment such as warning devices and/or pumps when the upper level is reached, and deactivates such equipment when the lower level is reached. The sensor is uniquely constructed of three specially coatedwater repellent probe elements which are received in a socket which is in turn imbedded in a molded body of plastic or the like to absolutely seal the sensing unit against corrosion and mitigate against the accidental bridging of the probes by oil slicks and bilge slime.

Abstract: A system for sensing and controlling the level of fluent material in a reservoir or other receptacle. In electrically conducting materials levels are sensed by low voltage direct current conduction between electrode pairs placed at desired "high" and "low" control levels which send D.C. digital logic sensing signals over connecting wires to very high resistance "high" and "low" inputs of a digital logic signal processing circuit, while nonconducting material levels are sensed by suitable transducers which upon immersion can send D.C. digital logic signals. The digital signal processing circuit receives the sensor signals and provides a digital output signal or absence thereof, depending on the relative state and sequence of the sensing signals and transmits a digital output signal to a solid state relay which controls the power of flow control means to maintain desired levels of the fluent material.

Abstract: A system for monitoring the liquid level in containers such as boilers and tanks. An electrode inserted into the container completes a path through the liquid when the liquid is at or above a predetermined level. When the liquid falls below the level, the path is opened. If the open path persists uninterruptedly for a timed period, an output device such as a relay is energized (or deenergized, if desired) to signal the low fluid level. The circuit path is powered at a low AC level from an AC source which also powers the output device. The low level AC in the circuit path to the liquid minimizes electrolytic and other problems within the container. The low level AC periodically resets a timing device within a direct current monitoring circuit before the expiration of the timed period, as long as the circuit path through the liquid remains closed. The output device is an optical coupling device isolating the output device from the timing device and from the low level AC path.

Abstract: A resistive fluid or boiler water type of detecting system has been disclosed. A single conductor type of probe having a plurality of conducting regions that are capable of conducting a bidirectional electric current in either a full bidirectional mode or in a unidirectional mode has been disclosed. The single probe element is capable of three separate and distinct states of operation. The first state is when there is an absence of current, the second is when there is a unidirectional portion of the bidirectional current flowing, and the third state is when the full bidirectional electric current is allowed to flow. An output device is responsive to these three states to provide different types or levels of control.

Abstract: An improved system for sensing and controlling the level of fluent material in two reservoirs when material is transferred from one reservoir to the other. In electrically conducting materials, levels are sensed by direct current conduction between electrode pairs placed in each reservoir at desired "high" and "low" control levels which send D.C. digital logic sensing signals from these four sensors over connecting wires to four high resistance input circuits of a digital signal processing circuit; in electrically nonconducting materials, levels are sensed by suitable transducers which upon immersion send D.C. digital logic sensing signals to the digital signal processing circuit.

Abstract: A new circuit is added to an electrical circuit including two electrodes underwater positioned very close to an air gun gaseous exhaust wherein the exhaust from the firing air gun momentarily blows away the conductive sea water from one or both of the electrodes to produce a high voltage pulse due to the large increase in resistance in the circuit indicating the precise moment of firing of the air gun free of any uncertainty and mechanical noise which normally affects conventional transducers.This new circuit added to the above circuit is a circuit polarity reversing circuit which includes particularly a positive current generator, a negative current generator, and a sea ground for forming a third electron source when any of the two electrodes becomes defective, thus forming a fail-safe system.

Abstract: A wire wound resistor is vertically disposed in a vessel. The resistor has a former of between 20 mm and 45 mm diameter and resistance wire of a resistance of between 1 and 4 ohms per turn connected in the circuit of an A.C. bridge circuit. Impedance change is indicated on a display unit calibrated to indicate the change in level of liquid e.g. milk in the vessel. The resistance wire is laid on the former by applying ultrasonic sound energy to soften the former which is of polysulfone or polycarbonate and the wire embedded in the softened former material. The vessel is shaped at the lower end to assist in giving linear readings when the level of liquid is low.

Abstract: A self-contained water alarm for monitoring floor moisture comprising a plurality of pairs of sensor electrodes mounted at spaced locations on the bottom of a donut-shaped housing that can be fitted over a standpipe, the sensor electrode pairs being incorporated in feet that support the housing on a floor; the housing contains a horn or other audible alarm device, a battery, and an alarm circuit including an SCR having its main anode-cathode disclosure path connected in series with the horn and the battery and in parallel with a manual test-reset switch, and having its gate electrode connected to one sensor electrode in each pair, the other sensor electrode in each pair being connected to the battery. An auxiliary pair of sensor electrodes are connected in the circuit, in parallel with the housing-mounted sensor electrode pairs, to permit simultaneous monitoring of floor moisture and of the water level in a sump or standpipe. Provision is made for connecting a remote alarm to the device.

Abstract: The invention is concerned with establishing the datum level of a lance or cartridge relative to the surface of a bath of molten metal in a metallurgical vessel. A voltage is applied to the movable lance or cartridge in such manner that contact of the lance or cartridge with the bath surface causes an earth leakage current to be established. Electrical circuitry is incorporated to open a circuit breaker upon flow of a predetermined earth leakage current and actuate an indication on a distance measuring device coupled to the movable lance or cartridge.

Abstract: A fluid level control circuit with a safety test function for a boiler water level probe of a fail safe type is connected to a field effect transistor controlled amplifier having a well defined threshold of operation. A safety test switch means is provided to pull the amplifier's input down below the threshold point, but not to a shorted condition. By observing the output of the system it is possible to determine whether the fluid level detector is properly installed, and whether the amplifier has had any type of unsafe operating failure.

Abstract: A sensor for determining the presence of a particular volume of fluid within a plurality of reservoirs maintained as a portion of an automatic mixed drink dispenser. Fundamentally, the invention includes electrical contacts maintained within each of the various reservoirs, the reservoirs being aligned into rows and columns to form a matrix. A multiplexing circuit is interconnected to the rows of such reservoirs while a sensing circuit is interconnected to the columns thereof. The addressing of the rows of reservoirs by the multiplexer enables a signal to pass across the contacts and through the beverage maintained within the reservoirs, this signal being sensed by the sensing circuit interconnected between the columns of reservoirs. "Empty" reservoirs, or those having a low beverage level, may be quickly isolated by a determination of the row accessed and the column sensed to result in the failure of a contact to pass a signal.

Abstract: An electrical instrument for detecting an interface between oil and water in a tank or other area; the instrument having an electrical circuit that includes a conductor to a lower-most probe and another conductor for selective connection to a series of probes at different elevations.

Abstract: A liquid level sensing electrode structure provided by flat cable which has a plurality of insulated conductors cut to various lengths with end portions exposed to provide sensing electrodes is used in a liquid level sensing system. A common electrode is provided for the system. A separate voltage inverter is provided for each sensing electrode and connects with a voltage source to provide a microprocessor compatible signal when liquid is presented to the common electrode and the sensor for the inverter. A liquid utilization apparatus having a liquid sensing system provides a flow of liquid along the electrode structure to prevent sediment buildup.

Abstract: A level indicator comprises a tubular probe immersed in the liquid to a depth defining the minimum liquid level in the reservoir. The probe communicates with a gas-filled chamber with a heating resistor therein. A warning member is connected to the gas-filled chamber to indicate that the level of the liquid reaches a minimum as indicated by no pressure increase occurring in said chamber.

Abstract: A device for monitoring the supply of electrically conductive recording fluid in a supply container for ink recording devices and other recording devices utilizing recording fluid, employing electrodes which are wetted by recording fluid and a circuit arrangement which detects the electrical resistance between the electrodes and triggers a display device when the amount of recording fluid falls below a specific volume, in which a plurality of electrodes are provided within the supply container, two electrodes of which define therebetween a fluid-specific standard resistance, formed by the recording fluid, and two electrodes defined therebetween a resistance, formed by the recording fluid, which changes in dependence upon the level of the fluid, with at least those electrodes which detect the fluid-specific standard resistance being disposed in an area of the supply container which is constantly wetted by fluid.

Abstract: A probe assembly is provided which includes a housing, at least one sensing element extending through a passageway in a wall of the housing and a sealing packing element mounted in the passageway for effecting a pressure-tight seal between the sensing element and passageway. The housing has a generally pipe-shaped neck portion, one end of which has disposed thereacross the housing wall through which the passageway extends, and the sensing element is at least partially disposed in the neck portion in a direction generally parallel to the longitudinal axis of the neck portion. The neck portion is filled with a heat-resistant, porous filler material, which prevents damage to the sealing packing element.

Abstract: The height of a body of electrically conductive liquid is measured by imming in the liquid an electrode forming an electrical resistance. The electrode is connected with two conductors electrically insulated from the liquid and tied, in turn, to an alternating-current source which is not connected to ground. The resulting network of electrode, conductors and alternating-current source forms an electrical circuit to which responds a device for measuring the potential difference which is a function of the liquid level between the potential of the liquid in a region outside the electrode-encircling stray current and a potential outside the electrode.

Abstract: A durable, long lasting liquid level controller utilizing an encapsulated, low current, solid state circuit, projecting metal probes arranged to minimize erroneous readings due to liquid adhering to the probes and a wave discriminating means as part of the encapsulated solid state circuitry, said wave discriminating means serving to eliminate false signals resulting from splash or wave action.

Abstract: A liquid level sensor of the bifilar wound inductive coil type is provided with improved end linearity characteristic. The coil ends are wound substantially to the end of a tubular support member, and a modified end support is provided at the support tube ends.

Abstract: A valve device for metallurgical containers includes an electric circuit formed by two electrodes opening out into the molten metal at the tapping point. The electric circuit measures the resistive voltage drop across the molten metal at the tapping point to determine the slag content in the tap stream by changes in the measured resistive voltage drop. The rate of tapping of the melt can be controlled simultaneously along with the indication of the presence of slag in the tap stream.

Abstract: A toilet installation is disclosed which is especially suited for pleasure boats. A discharge tank is disposed under a toilet fixture and connected with it through an inlet orifice. A flexible obturating member comprising a flexible flap member and a downwardly opening cup-shaped float member is fixed at one side of the inlet orifice so that the flexible obturating member hangs in the discharge tank when the latter is not pressurized. Compressed air from an air compressor is carried through a conduit for pressurizing the discharge tank and expelling the effluent from the discharge tank through a drain orifice, the outlet end of the conduit is aimed at the underside of the float member so that compressed air issuing from the conduit thrusts the obturating member against the inlet orifice thereby sealing off the discharge tank from the toilet fixture.

Abstract: A level sensing system for determining the quantity of a fluent or flowable material in a container including a level sensor and a monitor wherein the sensor is constructed of a pipe of non-conducting material with pairs of electrodes exposed to the fluent material and connected to resistance bars to produce a proportionate voltage signal across the resistance of the sensor in accordance with the quantity of fluent material. The monitor transforms the signal into a readable output.

Abstract: Various probes which are adapted to measure the liquid level in a vessel including the flow rate through a channel comprise a conductive probe electrode and guard electrode means including a rear portion located between the wall of the vessel and the probe electrode and a lateral portion extending outwardly from the lateral extremities of the probe electrode. The probe electrode and the guard electrode means are separated by interior solid insulation and an exterior solid insulation covers the probe so as to separate the guard electrode means and the probe electrode from the conductive liquid. By driving the guard electrode means at substantially the same potential as the probe electrode, the portion of a conductive coating which has accumulated at the lateral portions of the guard electrode means may be capacitively coupled to the potential of the guard electrode means thereby reducing the adverse effect of a conductive coating which has accumulated at the probe electrode.

Abstract: In a scum removing apparatus including a suction source, a suction pipe having one end communicating with the suction source and the other free end positioned above the surface of scum to suck the scum and apply water to the sucked scum in the vicinity of the free end, and a scum separator provided at an intermediate portion of the suction pipe, a device for detecting the level of the scum surface relative to the free end of the suction pipe. The detecting device comprises a pair of electrode rods provided on the outer periphery of the free end of the suction pipe and projecting from the pipe end by a suitable length, and means for detecting variations in the electric resistance between the electrode rods. The electrode rod comprises a tube having accommodated therein a slider slidingly projectable from the front end of the tube and slidingly retractable into the tube.

Abstract: A liquid level monitoring system functions by applying an alternating voltage to a probe. When the liquid level in a reservoir touches the probe, a low impedance to ground is present, thereby permitting current to flow to ground. When the liquid level falls below the probe, a high impedance to ground is created and current flows to a detector. The detector switches on an alarm which flashes an appropriate warning.

Abstract: An inductive level sensor has inductively coupled primary and secondary windings. Circuitry drives the primary with an AC signal of constant current magnitude and selected frequency f to induce in the secondary, a voltage signal V of magnitude .vertline.V.vertline., frequency f and phase difference .phi. from the driving signal. Circuitry operates to generate a voltage output signal proportional to .vertline.V.vertline. cos (.phi.-.theta.), where .theta. is a selectively set phase shift factor. By properly and selectively adjusting the frequency f and phase shift factor .theta., an output signal .vertline.V.vertline. cos (.phi.-.theta.) can be provided which self-compensates for changes in mutual inductance caused by operating temperature variations so that an output signal is produced which is substantially linearly proportional to changes in the level of a pool of liquid metal being monitored. Disclosed also is calibration circuitry and circuitry for converting the voltage signal .vertline.V.vertline.

Abstract: A device for checking the level of a liquid in a tank, for example a car fuel tank, has an electrical resistance probe partly immersed in the liquid and energized with a constant current. The voltage across the probe at switching on is stored and used as a reference for comparing with the increased voltage after the element has been heated to a value dependent on the length of resistor cooled by the liquid.

Abstract: Apparatus and methods for filling cans with measured amounts of wet material, having improved methods and procedures for the conveying and controlling the feeding of such materials. The height of the column of material maintained in an upright tube of the can filling unit is controlled by an electrical probe assembly and associated electronic circuitry. The probe of the assembly is positioned above the column of material, and the arrangement is such that when it is contacted by the upper surface of the column, the associated circuitry effects a reduction in the feed of material to the column.

Abstract: An Early Flood Warning System provides advanced warning of probable flash floods and/or stage floods to potential flood victims by collecting and analyzing rainfall and stream level data, and by providing means for disseminating alarms and instructions to individuals in threatened areas. Said Early Flood Warning System contains: a plurality of automated electronic digital liquid level gauges, some of which are specially adapted as rain gauges, and some of which are specially adapted as stream level gauges; a plurality of gauge actuated transmitters; a receiver; a decoder and validity logic unit; a data analysis unit; a central disaster alert station; and a plurality of disaster alert modules. Said digital liquid level gauges are energy and environmental intensive devices which electronically measure, using digital techniques, liquid levels such as rainfall and stream level, and transmit data by coded radio frequency (R.F.) signals to a central data analysis facility.

Abstract: A bearing joint has a body defining an internal chamber, an opening for supplying an electrically conducting fluid to the chamber, and an electrically nonconducting plug in the opening. An electrical conductor extends through the plug so that the electrical resistance can be measured through the fluid between the conductor and the body of the bearing joint.

Abstract: A system for measuring the height of material in a storage container by generating an incident pulse with a pulse generator and transmitting the pulse through a high impedance transmission line supported in a container. A reflected pulse of opposite polarity is generated at the interface of air and material in the container and is received by a reflected pulse detector which again triggers the pulse generator to continuously monitor the height of the material in the container. The time difference between the transmitted incident pulse and the received reflected pulse of opposite polarity is the indication of the height of the material in the container. A hold off delay disables the reflected pulse detector for a finite period of time so that the reflected pulse detector is not affected by noise signals on the transmission line. If no material is in the container and no reflected pulse of opposite polarity is received, then one automatic start pulse generator retriggers the pulse generator.