Abstract: A battery-operated fluid level monitor has a novel circuit and sensor for providing signals, both audible and visible, for indicating low fluid level, low battery voltage, and proper fluid level. The monitor is useful as a device that can inform when a Christmas tree needs water. The monitor can also be economically fabricated, and this is important for mass production applications, such as a Christmas tree monitor.

Abstract: The apparatus comprises a probe-insulator (3) with an internal cavity, a first system (8/1) that circulates a cold fluid within the cavity (4) of the probe-insulator in order to cool the latter to such a temperature that the external humidity condenses on the external surface, a second system (8/2) for measuring the surface conductivity on the probe-insulator, a third system for activating a washing plant of all insulators installed in the same area when the measured value of said surface conductivity reaches a pre-set critical value; the refrigerating device that produces said cold fluid preferably includes a group of Peltier modules.

Abstract: A process is disclosed for producing a swellable plastic resistive moisture sensor comprising dispersing an additive selected from the group consisting of carbon in powder, dust or soot form, carbon black, graphite, a metal in powder or dust form, and mixtures thereof, into a plastic comprising a polyimide or a copolyimide or both formed from diisocyanate and dianhydride reactants.

Abstract: A device for providing a signal emulating the wetness of plant leaves, includes a first generally horizontal surface; a second, generally upwardly facing sloped surface having an edge spaced above the first surface by a gap, so that drops of moisture can accumulate on the second surface, and run off the edge, bridging the gap, and first and second leads extending from the first and second surfaces, respectively, to measure the conductivity/resistivity across the gap. Also disclosed is a method of providing a signal emulating the wetness of plant leaves including the steps of: providing a first generally horizontal surface; providing a second, generally upwardly facing sloped surface having an edge spaced above the first surface by a gap, so that drops of moisture can accumulate on the second surface, and run off the edge, bridging the gap between the first and second surfaces; and measuring the conductivity/resistivity across the gap between the first and second surfaces.

Abstract: An apparatus for determining the boiling temperature of a brake fluid to in turn determine the water content therein includes an electrically heatable sensor element (13) immersed into the fluid under test, a power source (12) supplying a current of a constant amplitude, and a measuring system (15) for measuring the voltage drop on the sensor element (13). A stable cellular convection heat transfer mechanism into the surrounding fluid arises, with the voltage drop across the sensor element (13) being indicative of the boiling point of the fluid. The sensor element is in the form of a linear conductor (13', 20, 21) clamped on either end. The sensor element also may comprise a plurality of linear conductors (13', 20, 21) of this type connected in parallel or in series.

Abstract: A sensor for monitoring the water content and the acid content in the presence of water in nonaqueous media can be incorporated into a monitoring system for monitoring the quality of nonaqueous fluids in equipment or vehicles. The sensor comprises an insulating substrate; electrodes formed on the substrate in an interdigitated pattern; and a conductive polymer deposited over the interdigitated electrodes which bridges between adjacent digits of the electrodes. The monitoring system incorporating the sensor comprises a control module for measuring the conductivity of the sensor. The control module is preprogrammed to compare the measured conductivity to a predetermined level indicative of an unacceptable level of degradation. The sensor is made by depositing electrodes on an insulating substrate; depositing a conductive polymer over the electrodes in an amount sufficient to bridge between the electrodes; and neutralizing the conductive polymer to an insulating form.

Abstract: A water drop sensor comprises a pair of electrodes disposed in association with a portion of a surface of a vehicle window within a wipe pattern and having edges defining an extended insulating gap between the electrodes. The electrodes define a gap which varies in width over the range of diameters of drops to be sensed. The result is that the sensor shows more sensitivity to larger drops than to smaller drops as compared with a similar sensor having a constant gap width. The variation in gap width may be continuous or stepwise over the total range of drop diameters.

Abstract: The present invention includes a dielectric sensor which provides at least two signals corresponding to the sensed dielectric of a petroleum stream. A temperature sensor also senses the temperature of the petroleum stream and provides a corresponding temperature signal. Crossplot data arrange the two parameters associated with the petroleum stream dielectric is stored in a memory. The memory is accessed using signals from the dielectric sensor and the temperature sensor to select data from the memory. An output circuit provides a water cut signal in accordance with the selected data.

Abstract: An apparatus and a method for determining the water content of an oil-in-water emulsion is disclosed. The apparatus includes a first sensor for measuring the real part of specific admittance of the emulsion, a second sensor which acts as a temperature compensation device and electronic circuitry for producing a signal representative of the water content of the emulsion. The method for determining the water content comprises measuring the real part of specific admittance of an oil-in-water emulsion and providing a signal representative thereof, providing a reference signal indicative of the emulsion temperature, adjusting the measured real part of specific admittance signal with the reference signal and converting the adjusted signal into a current signal representative of the percentage water content of the emulsion.

Abstract: A soil moisture sensor to be implanted in soil. The sensor has a conductive metal housing, perforated to pass moisture to and through a filter liner which lines an internal cavity. A transfer matrix is confined in the liner and is abutted by a buffer tablet of compacted gypsum. An electrode matrix abuts the tablet and bridges a pair of spaced-apart electrodes. Water, or absence of water, in the electrode matrix provides a measure of moisture in the soil as a function of electrical conductivity between the electrodes.

Abstract: Apparatus for detecting corrosive conditions in pipelines comprises a wire having an electric potential different from the electric potential of the pipeline. The wire is disposed in the pipeline in a housing which prevents it from coming into contact with a pig used to clean the interior of the pipeline. The wire is spaced from the interior of the pipeline so that it normally is not in direct electrical contact with the pipeline. The wire extends out of the pipeline and is electrically connected to an indicator. The indicator is also electrically connected to the pipeline. When corrosive fluid, such as briny water, is present in the pipeline and comes into contact with the wire and the interior of the pipeline, an electric current is electrochemically produced due to the difference in electric potential between the pipeline and the wire. The indicator detects this current and indicates that corrosive conditions are present in the pipeline.

Abstract: Apparatus for testing shelled corn in a combine storage tank during harvesting includes a plurality of charged electrodes each in the form of an elongated rod arranged in a spaced manner and positioned in a lower portion of the combine storage tank to be completely encompassed by the shelled corn. The electrodes are coupled to a moisture meter located in the combine cab allowing the operator to determine the moisture content of the corn crop at harvest. The moisture meter is easily disconnected from the electrodes and removed from the combine to permit moisture testing of corn kernels while still on the cob prior to harvest.

Abstract: The present invention is a water cut monitor which includes a settling tank in which a quantity of fluid from a producing well is accumulated. The fluid is removed as a stream of fluid after a predetermined interval from the accumulation of the fluid by the settling tank so as to allow the accumulated fluid to separate into three phases: free water, water-continuous and oil-continuous. The flow rate of the stream of fluid is measured and a corresponding flow rate signal is provided as well as a temperature signal corresponding to a sensed temperature of the stream of fluid. The water cut monitor includes a plurality of electrodes in contact with the fluid. Injection electronics connected to at least one of the electrodes provides an injection voltage and injection current to the fluid stream and also provides signals corresponding to the injection voltage and injection current. A voltage in the fluid stream is measured and a measurement signal provided.

Abstract: A sensor and system for monitoring the accumulation of contaminants in oil wherein the contaminants have an electrical conductivity which is different from the oil. An electrochemical cell is used to measure the alternating current conductivity of the oil to provide an indication of the amount of contaminants present in the oil. Acids and water are two common engine oil contaminants which are accurately monitored by this alternating current conductivity measurement system.

Abstract: A moisture detecting system employs a body of porous concrete with electrodes embedded therein. The body of concrete is contained within a housing having an opening in the top thereof to admit rain. The body may also have electrical probes therein connected to the electrodes, which probes can be embedded in the ground to detect moisture therein.

Abstract: The disclosure relates to a system for measuring relative humidity and temperature wherein there are provided three controlled switching matrices, a first of the matrices determining whether a current for determining temperature or relative humidity is to be fed via a diode to a system voltage output from when the voltage output will be converted to an appropriate temperature or relative humidity reading. The remaining two matrices are each controlled by an oscillating voltage which alternates the output or input terminal thereof depending upon whether the oscillating voltage is positive or negative. This causes current to be passed through a humidity responsive resistor in opposite directions during each half cycle of the oscillating voltage. In the case of humidity sensing, the diode used for measuring temperature also acts as a temperature compensating device for the humidity sensor, thereby having a dual function in the system.

Abstract: A brake fluid tester for measuring the quality of brake fluid, comprising means for measuring the conductivity of the brake fluid, preferably comprising a plurality of comparators for comparing the resistance of the brake fluid to a plurality of reference, resistances. The device further comprises indicating means, preferably light emitting diodes, responsive to the measuring means for indicating the quality of the brake fluid based upon its measured conductivity. An increasing number of diodes are illuminated as the conductivity of the brake fluid increases, providing a positive indication when the device is working and providing an easy to interpret display of the test results. The diodes are preferably activated at preselected levels of conductivity, corresponding to preselected levels of moisture contamination.

Abstract: A humidity sensing apparatus which includes a humidity sensor which detects humidity as a function of impedance is provided. A reference resistor has a predetermined resistance value. A charge switching circuit selectively couples one of the reference resistor or the humidity sensor in series with a reference capacitor which has a predetermined capacitance. A voltage judging circuit determines whether the terminal voltage of the reference capacitor is high or low. A charge/discharge switch selectively charges and discharges the reference capacitor in accordance with the output of the voltage judging circuit. A sensor direction switching circuit inverts the direction of current flowing through the humidity sensor during charging of the reference capacitor. An oscillation frequency counter counts the number of charge/discharge cycles which are repeated during a predetermined time period.

Abstract: The device comprises: a high frequency alternating voltage generator the output of which is connected to a sensor probe 5 which is to be applied to a substrate to be measured, an amplifier the input of which is connected to the sensor probe, and a detector arranged to furnish a D.C. voltage signal based on the output from amplifier. The generator, the amplifier and the detector are located inside a metal envelope enclosure. An electromagnetic radiation shield is disposed inside the envelope to separate the amplifier and the detector from the high frequency generator. In operation, voltage output from the detector is indicative of the electrical impedance of the substrate as sensed at the probe. In the preferred application, the substrate is skin and the measured electrical impedance is indicative of the water content of the skin.

Abstract: A soil permeameter and method of measuring soil conductivity utilizes a core device that is open at one end that is inserted a measure depth into the soil to be tested. A vertically elongated measuring column is connected to the core device and both are supplied with water sufficiently to develop a pressure head in the column. A timer and a data storage device responsive to the timer are provided to measure and store the time intervals for the level of liquid in the column to fall equal increments. The value of soil conductivity is calculated as a function of the depth of core insertion and the stored time intervals. Both horizontal and vertical components of soil conductivity can be determined separately.

Abstract: A corn moisture tester is adapted to measure the moisture content of corn kernels on an ear of corn. The ear of corn may be affixed to the corn stalk. The device includes an ear cradle, a pair of electrode blades and circuit for measuring a moisture-dependent electrical property of the corn kernels. The cradle is adapted for receiving an ear of corn and includes two portions hinged together so they may be opened to receive the ear. When the cradle portions are closed, they form a substantially cylindrical interior cradle surface for engaging the ear of corn. The conductor blades are mounted to one portion of the cradle to pierce the kernels but not the cob when the cradle is closed about an ear under test. The electrical property measuring circuit generates and displays a signal representative of moisture.

Abstract: A moisture and dew-detection sensor comprises a fabric and a moisture sensing resistive substance adhered in a substantially continued and dispersed state to the fabric, and a plurality of fine voids are formed in the moisture and dew-detection sensor. A response time and an accuracy of the sensor in accordance with the present invention are superior due to the existence of the plurality of voids.

Abstract: A method for evaluating characteristics of a printed wiring board by measuring the alternating current impedance spectra of the printed wiring board conductor pattern. The method is useful in evaluating a number of different characteristics, such as moisture content, delamination, interlayer thickness and surface characteristics.

Abstract: Apparatus for sensing moisture in crop material includes a probe mounted on a pickup of an agricultural baler for movement between a retracted position and an operative position. The probe has a pair of fingers arranged in a spaced apart relationship so that crop material picked up by the baler bridges the space between the fingers when the probe is in the operative position thus creating a signal path between the fingers. The moisture sensing apparatus also includes a cam roller carried on the pickup to move the probe from its retracted position to its operative position, and a computer connected to the probe to measure the conductance level of the crop material creating the signal path.

Abstract: A high voltage electrode device including a plurality of individual electrodes having end portions projecting beyond an insulating surface and arranged to form at least one group or electrically connected electrodes and apparatus for energizing and deenergizing each group of electrodes. The energizing and deenergizing apparatus includes a high voltage source associated with a respective group and having a control input for turning off the high voltage source wherein the high voltage source provides an output to the group via a current measuring device providing an output indicative of the current measured. A voltage measuring device is connected to the associated group and provides an output indicative of the voltage measured, and quotient forming unit responsive to the outputs of the current measuring device and the voltage measuring device forming a quotient thereof and providing an output when the quotient formed has a predetermined relation to a reference value.

Abstract: A method and apparatus constructed to measure the fluid present in a multifilament or fiber strand moving at high speed is described and involves conductive contact points along the strand path which contact the strand and generate signals. The signals which are conductance measurements are synchronously demodulated to produce a signal representing the volume of fluid in the strand.

Abstract: A means and method for determination of the pore structure of porous materials using electrical conductance. A sample of porous material is saturated with electrolytic solution and positioned into a container. Temperature and conductance of the sample are monitored as temperature is varied. The temperature is varied so as to create phase transitions in at least a portion of the electrolytic solution existing in the sample. The control means can be utilized to control the sequence of temperature changes and to receive and record the temperature and conductance readings. Alternative means for accomplishing the method of the invention are disclosed, including a specific means for positioning a sample, attaching electrodes to its opposite sides, and attaching a temperature sensing device to the sample, and at the same time isolating and insulating all electrical connections.

Abstract: A system for detecting a fault, e.g. a liquid leak from a pipe or vessel containing an electrolyte or a hydrocarbon. In one embodiment, the system comprises a central unit and a plurality of sub-units; each of the sub-units is powered in turn from a power source in the central unit, and the sub-unit generates a signal which is observed by the central unit and which identifies the presence of a fault. In another embodiment, signals generated by a detection system at different times are compared and the decision whether to generate a fault alarm is based on that comparison.

Abstract: A method of producing an exhaust gas sensor incorporating BaSnO.sub.3. Stannate ion and barium ion are reacted in a strong alkali to precipitate water-containing crystals of BaSnO.sub.3 such as BaSnO.sub.3.3H.sub.2 O, BaSnO.sub.3.5H.sub.2 O or the like. When thermally decomposed, the precipitate gives BaSnO.sub.3 free from segregated Ba and Sn elements. The product was then molded and thereafter sintered to obtain the sensor.

Abstract: A fabric moisture detector and method is provided. The detector has a supt insulating structure, and a pair of electrodes, which have a pair of opposite faces separated by a gap of selective thickness, such as four inches or ten centimeters. The detector also has a current sensor, for measuring the current through the gap during the application of a relatively high voltage, such as about 10,000 volts to 60,000 volts for a ten centimeter gap. The voltage applied using a ten centimeter gap can be between about 1,000 volts per gap centimeter to 6,000 volts per gap centimeter. The process includes the steps of measuring the gap current during the application of the specified voltage, whereby a dry fabric or bare electrodes yields substantially no current and a wet fabric yields a peak current.