Abstract: A two-wire, admittance-responsive instrument system in which a transmitter, receiver and calibrator are connected by a two-wire transmission line is disclosed. The calibrator repetitively transmits a calibration enabling signal causing the transmitter to increment a reference admittance for comparison to a sensed admittance corresponding to a known physical condition. The calibrator monitors the bistable output signals transmitted by the transmitter in the calibration mode, which changes state when the incremented reference admittance bears a predetermined relationship to the sensed admittance. The calibrator may then transmit additional calibration enabling signals causing preload to be established for transmitter operation.

Abstract: Apparatus for the ratiometric measurement of a quantity of liquid in a tank includes first and second capacitors disposed in a tank and responsive to an AC excitation signal. The output signal from the first capacitor corresponds to the quantity of liquid in a tank, while the output signal of the second capacitor corresponds to an empty tank condition. First and second rectifiers are respectively coupled to the first and second capacitors. Preferably, the rectifiers are each a diode pair of opposite polarity diodes. The output signal from each rectifier is thus a current signal. A first current-to-voltage converter is coupled to both the first and second rectifiers and provides a first voltage signal corresponding to the first and second rectified signals. A second current-to-voltage converter is coupled to the second rectifier and provides a second voltage signal corresponding to the second rectified signal.

Abstract: Robotic liquid separation operates independently of liquid volume, viscosity, or optical characteristics, by sensing changes in the dielectric constant of the liquid as it is being drawn through a cannula. The cannula has electrodes which form a sensing capacitor for detecting the changes in the liquid dielectric constant as the liquid is drawn therethrough.

Abstract: A level indicator control system including a microprocessor that controls the height and, therefore, the amount of the substance, such as fluid or granular solid, to be contained in a closed or open tank or vessel. The system provides calibrated digital or analog output that shows the extent to which the tank is filled with substance at substantially any level. A scale, in percent, each value representing the percentage of fullness of the tank, is produced after low and high limits, representing any low and high substance levels respectively, are provided to the microprocessor. The scale values are a function of the changes in capacitance between the stationary probe and the tank wall as the level of substance approaches or submerges the probe. The system finds its probe capacitance and sets its own high and low control set point limits automatically.

Abstract: An improved capacitance bridge type liquid level control system for use in refrigeration applications is disclosed which provides improved apparatus for sealing the probe in its mounting and for insulating same against the condenser reservoir stand pipe in which it is mounted. Improved sealing between the probe and probe body is accomplished through an annular PTFE seal which when compressed pushes inwardly to seal a tubular PTFE insulation against annular ridges in the side of the probe rod proper. The improved probe rod shape also maintains a proper stabilized axial alignment between the probe rod and the probe body.

Abstract: A sensor for sensing the level of oil or transmission fluid under both normal and extreme temperature conditions. The only active components of the sensor have input and leakage currents substantially lower than those of diodes and current sources under high temperature conditions. The sensor has a probe, including a pair of electrodes forming a level detecting capacitor, adapted to extend in the vessel to detect the level of the liquid. A reference capacitor is included which has a capacitance substantially the same as the capacitance of the level detecting capacitor when no dielectric liquid is present between the electrodes of the level detecting capacitor. Circuitry is provided for measuring the capacitance of each capacitor and for deriving from the capacitance measurements a signal proportional to the level of the dielectric liquid at the sensor. Circuitry is also provided for testing whether the reference capacitor is operating properly.

Abstract: A system and probe for indicating the level of material in a vessel as a function of material capacitance comprising a resonant circuit including a capacitance probe adapted to be disposed in a vessel so as to be responsive to variations in capacitance as a function of material level. An rf oscillator has an output coupled to the resonant circuit and to a phase detector for detecting variations in phase angle as a function of probe capacitance. Level detection circuitry is responsive to an output of the phase detector and to a reference signal indicative of a predetermined level of material for indicating material level as a function of a difference between capacitance at the probe and the reference signal. In the preferred embodiments of the invention disclosed, an automatic calibration circuit adjusts the resonance characteristics of the parallel resonant circuit of the reference signal indicative of a predetermined reference material level.

Abstract: A sensor for resolving the left-right ambiguity encountered in horizontal line hydrophone arrays consists of an orthogonal pair of dipole hydrophones, a monopole hydrophone, and a tilt sensor, the tilt sensor connecting the dipole hydrophones so as to provide a single dipole hydrophone which is always oriented horizontally. The tilt sensor consists of two variable capacitors made from hollow cylinders of high permittivity dielectric material, partially filled with a quantity of liquid mercury which forms the variable inner electrodes of the capacitors. The outer electrodes of the capacitors, on the outside of the cylinders, having a sinusoidally-shaped perimeter and being oriented at right angles to each other, are connected to the crossed dipoles in order to provide the required horizontal dipole hydrophone.

Abstract: A multiple set point material condition monitoring system includes a material responsive sensor developing a material condition dependent admittance and a reference admittance generator, generating a plurality of different admittance values in a predetermined sequence repeatedly during operation of the system. The circuitry coupled with the sensor and the reference admittance generator outputs a signal which is a function both of the material condition generated admittance and each of the plurality of reference admittance values, in sequence. Storage means are provided for storing a characteristic of the output signal for feedback to the circuitry when that particular reference admittance value for generating that output signal is again generated by the reference admittance generator. Preferably, the sensor and reference admittance generator are coupled across each of a pair of arms of bridge network which constitutes part of the circuitry developing the output signal.

Abstract: A resistive water probe is used in combination with a Christmas tree stand to detect a low water level. A low water situation activates lights in a Christmas tree ornament.

Abstract: A probe developing an admittance with a material whose condition is to be continuously measured is capacitively coupled with a variable frequency oscillator, preferably one having a digital output stage, for generating a variable frequency signal having a period varying with the admittance developed at the probe. Both the oscillator input and output are capacitively coupled to the probe. In a preferred embodiment, a set point circuit including a plurality of resistors coupled in parallel with the oscillator output and a plurality of switches coupled in parallel with the probe conductor and each with a different one of the resistor, provides easy circuit adjustment for use of the system with a variety of materials. A preferred digital circuit employing a pair of flip flops, fixed timer and one shot generate a fixed period variable duration duty cycle digital voltage level signal for transmission, if desired, or for conversion into a variable current signal.

Abstract: A bladder is disposed coaxially within a cylindrical container main body, a holder projecting into the bladder is provided on a top wall plate of the container main body, a sensor opposed to a bottom portion of the bladder and positioned within a moving locus region of the bottom portion or a deformable portion of the bladder is disposed at the bottom portion of the holder, and thereby, when the bladder deforms in response to variation of a liquid pressure the bottom portion of the bladder or the deformable portion of the bladder would actuate the sensor.

Abstract: A single capacitor is used to measure the oil level in an engine or transmission and compensate the sensed capacitance for changes in dielectric constant. Measurements are made for two different running conditions, one giving a capacitance reading dependent only on dielectric constant and one giving a capacitance dependent on oil level as well as dielectric constant. The transmission application uses a capacitor that is fully immersed in oil when the engine is off and partly immersed when the engine is idling, so that both types of measurements can be obtained. The engine application uses a capacitor having an upper section spaced from a lower section. Only the lower section is immersed during engine idle to render dielectric constant information, while the upper section is partly immersed when the engine is off.

Abstract: An overfill sensing system uses a capacitive sensor (12) on the interior of a tank for sensing the presence of a liquid to cease the filling process. The capacitive sensor (12) includes a sensing capacitor (16) and a reference capacitor (18) on separate arms of a bridge circuit (22). An oscillator (28) supplies an AC signal to the bridge circuit (22) divided by a variable resistor (30 ) to balance the bridge (22). A comparator (24) receives the output on each arm of the bridge (22) to sense a differential therebetween. When a liquid reaches the sensing capacitor (16), the capacitance changes from a predetermined capacitance, thereby changing the differential. A control circuit (14) is responsive to the differential at the output of the comparator (24) for visually indicating the status of the filling process and ceasing the filling process from the filling facility when a liquid has been detected.

Abstract: A water pump control system, such as for a boat, including a battery operated main motor-and-pump unit and a backup motor-and-pump unit. A pump turn-on transistor operates a relay to turn on the main motor-and-pump unit when the water level rises to a high level. A touch switch may be used to turn on the pump turn-on transistor independent of the water level. A pump turn-off transistor, which is turned on by the relay, keeps the main motor-and-pump unit on until the water level drops to a low water level. A backup motor-and-pump unit comes on if the main motor-and-pump unit has not come on after the pump turn-on transistor has been turned on.

Abstract: A probe comprises a plurality of longitudinally extended conductors forming a probe electrode, a laterally displaced ground electrode and two laterally displaced active guard electrodes interposed between the probe electrode and the ground electrode. The conductors are surrounded by solid insulation and the probe guard electrodes are driven at substantially the same potential as the probe electrode. The probe is utilized to measure the condition of materials in which the probe is immersed.

Abstract: A capillary tube viscometer is provided in which the viscosity of a fluid can be measured at a temperature above the normal boiling point of at least one component in the fluid. The fluid is heated to the desired temperature in a sealed viscometer which is constructed so as to withstand high pressure. The fluid is then allowed to flow through a capillary tube and the time required for the fluid to flow through the capillary tube is measured. The viscosity of the fluid is then calculated based on the Hagen-Poiseuille law.

Abstract: A non-invasive liquid level sensor assembly includes a pair of conductive band electrodes oriented in parallel, narrowly spaced relationship and disposed so that the gap between the electrodes corresponds to the liquid surface level to be detected. The electrodes are secured to the outer surface of a liquid container, and connected to a capacitive detector device which measures the change in electrical capacity between the conductors as the liquid rises or falls past the level of the gap between the electrodes. A shield electrode is also provided, disposed outwardly of and concavely about the sensing electrodes to eliminate sensitivity to masses outside of the container. In one embodiment the electrodes are secured with a sealed, arcuate housing which is adapted to be permanently or temporarily secured to the exterior of a liquid container by adhesive, removable straps, or the like.

Abstract: Apparatus for sensing liquid levels in fluid transfer mechanisms and the like comprises a conductive member supporting containers for sample liquids, the conductive member being rotatably mounted for positioning selected containers under a conductive pipette probe. A low-frequency oscillator is capacitively coupled to the conductive member for generating an alternating electric field and producing an electrical signal at the probe. As the probe is lowered toward the liquid, an amplifier circuit monitors an electrical signal received by the probe. When the probe contacts the liquid, the amplifier detects a signal level in excess of a threshold level and produces an output signal for inhibiting the downward movement of the probe at the moment of contact with the liquid.

Abstract: A liquid level sensing system having a sensing head with a pair of mutually insulated metal electrodes, one of the electrodes connected to the output of an amplifier and the other to the input. The gain of the amplifier is sufficienty high such that it will oscillate when the electrodes are immersed in a liquid and will be non-oscillatory when the electrodes are in air. The oscillation of the amplifier is detected to produce a signal corresponding to the presence of a liquid and also its characteristic.

Abstract: A liquid sensor system particularly suitable for commercial washing machines for drinking glasses and soft drink dispensers employs a capacitive detector providing a tortuous path through which the liquid passes and constituting part of the dielectric of the resultant capacitor. The pumps supplying the liquid through the capacitor to the dispensing means are controlled in accordance with the capacitance, as measured by a circuit. A preferred measuring circuit comprises a pulse generator; one series of pulses split from the generator output is delayed by a fixed period and fed to a flip-flop, while the second series also from the generator output are delayed by a period dependent upon the sensor capacitance and are also fed to the flip-flop, the output of which is dependent upon which series of pulses is in advance of the other. The circuit also provides for automatic adjustment of its sensitivity upon start-up or reset to adjust for differences in the sensors and the liquids.

Abstract: A liquid concentrate dispensing apparatus having a removable and refillable concentrate tank with sensors connected therewith flush with the inside wall of the tank to facilitate cleaning. The sensors comprise detectors which include an electrically conductive housing, one wall of the housing is substantially flush with the inside wall of the tank. Spring biased detent members on the outside of the tank releasably connect the detectors with the dispensing apparatus when the tank is inserted to a preselected position. The tank is provided with two such sensors, one is located in the sidewall and the other is located in the bottom wall. When the tank is inserted into the dispensing apparatus, the spring biased detent members engage contacts on the apparatus. A current passes between the detectors on the sidewall and bottom wall when both are covered by liquid concentrate.

Abstract: Sensor for an apparatus for measuring the level and/or the quantity of a liquid medium in a vessel, for example a pressure vessel, provided with a carrier which may be mounted in the wall of the vessel, a first pipe fastened to the carrier and a second pipe positioned concentrically and insulated within the first pipe, which second pipe may be connected through a bushing member positioned in the carrier, wherein a conductor is wound at least locally on the first pipe, which conductor is insulated with respect to the first pipe and may be connected through a bushing member positioned in the carrier.

Abstract: A universal fuel quantity indicator apparatus (100,102) includes a digital fuel quantity indicator (100) having an internal microprocessor control unit (104) and a removably connectable digital calibration trim unit interface (102) which enables the fuel quantity indicator (100) to be reconfigured for different fuel tanks by varying selectable fuel tank parameters, such as constants associated with a fuel quantity determination based on calculations of capacitance of a tank capacitor array (110) and a compensator capacitor (112).

Abstract: A two-wire, admittance-responsive instrument system in which a transmitter, receiver and calibrator are connected by a two-wire transmission line is disclosed. The calibrator repetitively transmits a calibration enabling signal causing the transmitter to increment a reference admittance for comparison to a sensed admittance corresponding to a known physical condition. The calibrator monitors the bistable output signals transmitted by the transmitter in the calibration mode, which changes state when the incremented reference admittance bears a predetermined relationship to the sensed admittance. The calibrator may then transmit additional calibration enabling signals causing preload to be established for transmitter operation.

Abstract: A calibration apparatus and associated method for the measurement of valuable fluids in storage or at the point of transfer. More particularly, a calibration apparatus and method for use with capacitive liquid level measurement systems.

Abstract: A toner concentration monitor senses changes in the effective dielectric constant of a developer mixture whose dielectric constant changes with variations in the toner concentration in the mixture. The monitor is the type having a capacitive probe immersible in developer mixture such that the capacitance value of said probe varies with the effective dielectric constant of the mixture. Means are provided for creating an electrical pulse train signal of predetermined frequency and variable pulse width. The pulse width is adjusted in response to the capacitance value of the probe. The pulses are created by a multivibrator circuit which is turned on by clock pulses and which has a time constant determined by the capacitance value of the probe. Each pulse has a first portion of fixed duration and a second portion of duration variable with the capacitance value of said probe.

Abstract: Method and apparatus for deriving a correction factor used in calculating corrected liquid (e.g., fuel) quantity of a tank having a probe capacitance which varies in accordance with the quantity of liquid contained within the tank. The correction factor reduces sensing diode voltage drop errors and stray capacitance errors (affecting the capacitance of the probe) through use of a switchable high/low amplitude Lo-Z oscillator. All oscillator outputs are "low" amplitude relative to the output amplitudes of conventional devices. Signal processing is effected by inputting raw data (both reference and probe-sensed signals) to an analog-to-digital sampling circuit, which raw data are used for deriving the correction factor. The correction factor is then applied to the raw data to determine a corrected liquid quantity indication. Recalibration of the correction factor periodically permits automatic adaption to changing error magnitudes (i.e.

Abstract: A probe device comprises a two-channel capacitive measuring sensor together with two further single-channel capacitive measuring sensors so disposed that the tips of the sensors are disposed in a common horizontal plane, the sensors being operable to detect the position and speed of movement of an interface between first and second phases in a system made up of at least two phases, such as a gas-solids fluidized bed. The data obtained when the probe is contacted by a gas bubble in the fluidized bed serve as the basis for them ascertaining the condition of and thus the reaction procedure taking place in the bed.

Abstract: A characterized inner electrode for a capacitive fuel-gauging probe comprises several discrete tubular sections of different diameters which are joined together end-to-end by metal coupling pieces. One or more of the tubular sections has two regions of different diameters that are continuous with one another, the smaller diameter region being formed by swaging down from the larger diameter region. The coupling piece has two shoulders to which the ends of the tubular sections are electron-beam welded. The coupling piece also has respective annular recesses into which a low viscosity adhesive is introduced via overlying apertures in the tubular sections after welding, so as to form an adhesive joint between the coupling piece and the tubular sections. The ends of the coupling piece are a close fit within the tubular sections and extend into them by a distance at least twice the diameter of the coupling piece.

Abstract: An apparatus for evaluating the performance of a dielectric substance includes: at least a pair of electrodes disposed in contact with the dielectric substance to be measured; a power supply for applying a pulse voltage to the electrodes; a current detector for detecting a transient response current flowing between the electrodes dependent on the component of the dielectric substance disposed between the electrodes; and a signal processor for evaluating the performance of the dielectric substance. The performance evaluation may be performed based on at least one of a peak value of the transient response current at a certain period of time, a difference between the peak value and a value at a fixed period of time after the peak value, and a ratio of the peak value to the difference between the two values. With this method and apparatus, the performance of the dielectric substance can quantitatively be evaluated.

Abstract: An aircraft fuel gauging system has a capacitance level probe mounted in a fuel tank that receives an alternating signal from a drive unit. The output of the level probe is connected to two diodes one of which is connected in series to earth and the other of which is connected in the opposite sense to a measuring unit. The measuring unit includes a signal conditioning unit which is switchable between operating as a d.c. current to voltage amplifier and a d.c. voltage amplifier by switching a resistor out of or into series connection with the diodes. A constant current source backs off the current from the probe when the tank is empty. Periodically, the supply of signals from the drive unit is interrupted and the conditioning unit is switched to operating as a d.c. voltage amplifier, the measuring unit measuring the voltage drop across the two diodes caused by current from the constant source.

Abstract: An electrode (10) intended for measurement of relative permittivity. Each one of the electrically conductive electrode elements of the electrode (12) of an even number, e.g. n, there being electrodes includes a corresponding line wire (20 and 22, respectively) for connection to a measuring bridge or the like. The electrode elements (12) are mutually separated by means of spacer means (18) of electrically insulating material. The lead-in wires (20,22) of adjacent electrode elements (12) can be connected in pairs for measurement. The electrode elements (12) are arranged on an electrode body (14) shape like to a rod and of an electrically insulating material. The electrode elements (12) are tubular and are arranged in recesses (16) with adapted measures in the electrode body. The spacer means (18) comprise of annular members intergral with the electrode body (14).

Abstract: A system for indicating level of material in a vessel as a function of material capacitance comprising a pair of parallel probe electrodes which extend through the vessel and have lower portions disposed beneath the vessel outlet in direct electrical contact with material whose level is to be measured. An electrical signal having both ac and dc components is fed to one of the electrodes, and detected at the other electrode, such that the detected ac signal component varies with both capacitance and conductance of material disposed between the electrodes while the dc signal component varies substantially as a function solely of material conductance. The dc signal component is used to compensate the ac signal component for variations in conductance, so that an output signal is provided which varies as a function of material level between the electrodes substantially independently of material conductance.

Abstract: A system for indicating the level of material in a vessel as a function of material capacitance comprising a resonant circuit including a capacitance probe adapted to be disposed in a vessel so as to be responsive to variations in capacitance as a function of material level. An rf oscillator has outputs coupled to the resonant circuit and to a phase detector for detecting variations in phase angle as a function of probe capacitance. Level detection circuitry is responsive to an output of the phase detector and to a reference signal indicative of a predetermined level of material for indicating material level as a function of a difference between capacitance at the probe and the reference signal. An automatic calibration circuit adjusts the resonance characteristics of the parallel resonant circuit. A remote module provides facility for initiating a system-test and a system-calibrate operation, either individually or sequentially.

Abstract: A gauge for measuring the height of a liquid in a vessel comprises a measuring electrode (M) and a compensation electrode (R) in the vessel, and a circuit which measures the capacitance C.sub.M of the measuring electrode and the capacitance C.sub.R of the compensation electrode, each with respect to a wall of the vessel as counter-electrode, using the liquid in the vessel as dielectric. The quotient C.sub.M /C.sub.R varies with the height of the liquid in the vessel. The measuring electrode and the compensation electrode are parallel and of the same length, but differ in surface area and shape to such extent that such quotient varies as a linear function of the height of the liquid in the vessel.

Abstract: Apparatus for gauging physical dimensions of solid or tubular bodies. Apparatus comprises a capacitive transducer having electrodes forming diametrically arranged pairs of capacitors and means for connecting the pairs, preferably sequentially, in an arm of a four arm electrical network. For circumferential scanning of a solid body along its length, the body is moved along a path of travel through a head assembly including the transducer with the axis of the body being coincident with the axis of the transducer. As the body moves through the transducer the diametrically arranged pairs of capacitors scan the surface to result in a surface profile of the body. For scanning the bore of a pipe or tube the transducer is inserted as a probe and moved along the bore of the pipe or tube, means being provided for maintaining the probe coaxial with the pipe or tube.

Abstract: Diesel fuel tends to deposit an insulating coating on surfaces it contacts. A probe, preferably in the form of a siphon tube, is coupled to a detection circuit which is responsive to either low resistance or high capacitance between the probe and ground. The probe is initially uncoated to make a resistive coupling to a fuel container when accumulated water touches the probe. When insulating deposits from the diesel fuel or other fuel oil coat the probe, capacitive coupling will occur between the probe and the accumulated water. In either case the presence of water triggers an output signal by the detection circuit.

Abstract: A system for indicating level of material in a vessel as a function of material capacitance comprising a bridge circuit which includes a capacitance probe adapted to be disposed in a vessel so as to be responsive to variations in capacitance as a function of material level. An adjacent bridge arm includes a plurality of capacitors coupled to controlled electronic switches for selective connection into the bridge circuit. The bridge circuit is powered by an rf oscillator, and a differential amplifier is connected across the bridge circuit for detecting the balance condition of the bridge. An automatic calibration circuit includes a digital counter having outputs connected to the electronic switches. A comparator is responsive to the differential amplifier for enabling operation of the counter during a calibration mode of operation for selectively connecting the fixed capacitors into the bridge circuit until a preselected balance condition, corresponding to a preselected reference material level, is obtained.

Abstract: The inside surface of a conductive vessel (preferably spherical) with insulated adjacent segments is coated with a dielectric layer. The vessel is then partly filled with a conductive liquid-like material such as mercury having an upper surface which remains approximately horizontal irrespective of the inclination of the vessel. The capacitance between the segments and liquid varies as a function of the vessel's inclination. Vibration-induced surface action also produces varying capacitance which can be detected for seismometer applications and the like.

Abstract: A device for determining the position of an interface between different fluids in a tank or container is provided. This device has a plurality of cells, placed one below another and mounted on a structure which is placed in the tank or container, each cell consisting of three electrically conductive elements, isolated from each other, the first element of each cell being adapted to be connected to an AC signal source, the third element of each cell being adapted to be connected to zero potential, and the second element of each cell being adapted to be connected to a receiver for detecting the transmitted AC signal.

Abstract: A fuel volume measuring system for an automotive vehicle in which fuel volume detection signals are simply averaged during a relatively-short averaging time period at regular measuring cycles when the vehicle is being refueled, and further weight-averaged or moving-averaged at regular measuring cycles when the vehicle is running. Therefore, fuel volume can be indicated quickly at a high response speed when the vehicle is being refueled and additionally fuel volume fluctuations can be minimized when the vehicle is running. Further, the system according to the present invention discloses the method of detecting the state where the vehicle is being refueled on the basis of the fact that the difference between at-least one of the current data signal indicative of fuel volume and at-least one of the preceding data signal indicative of fuel volume exceeds a predetermined value.

Abstract: A sensing apparatus including: a first electrode member; a second electrode member arranged at opposing positions a predetermined distance away and electrically isolated from the first electrode member; and an electric circuit connected to the first and second electrode members. The first and the second electrode members are operatively connected by an impedance formed between the first and the second electrode members in response to existence of a substance to be sensed between the first and the second electrode members. The electric circuit outputs a signal in response to the impedance. The sensing apparatus is applicable for detecting, for example, the level of a liquid in a vessel.

Abstract: Apparatus for measuring level and quantity of fuel oil stored in a tank, which comprises a pair of electrodes, one being a number of segmented electrodes while the other is an elongated electrode to form a number of capacitors, a source for applying high frequency voltage to said electrodes one by one to generate electric signals, means for converting said signals to corresponding high frequency signals, means for computing height of said liquid level from frequencies of signals, and means for computing the fuel quantity. Said capacitor probe is prepared by fastening an elongated flexible substrate IS printed with said electrodes round a rigid bar S, covering the outer surface thereof with insulative material, and fitting a metallic tube. Said segmented electrodes are arranged lengthwise in two rows in zig-zagged and partly overlapped.

Abstract: The capacitor probe is made up of two parts, both of which are in fluid communication with the interior of the tank or pipe the liquid level of which is to be measured. One part (7) of the probe is located at the bottom of the probe and acts as a reference capacitor. The other part (4) of the probe extends upwardly to the maximum liquid level to be measured. The part (4) includes two identical measuring capacitors, one of which is connected to the reference capacitor.

Abstract: A liquid level measurement capacitance probe is disclosed comprising an elongated outer capacitor tube, an elongated inner tube coaxially mounted within the outer capacitor tube to form a capacitor annulus therebetween with the inner tube having a plurality of longitudinally extending capacitor elements cooperating with the outer capacitor tube to form a plurality of individual capacitor units, a connector unit for electrically connecting the capacitor units to an electronic circuit processor for measuring capacitance values of the capacitor units in calculating a fluid level, a filter for separating water from fuel flowing from the storage tank to be measured to the capacitor annulus, the filter having an annular housing mounted about the outer capacitor tube with an inlet port adapted for fluid communication with the storage tank, an outlet port connected to the capacitor annulus between the inner and outer capacitor tube for delivery of filtered fuel to the annulus, a water discharge outlet for discharging

Abstract: A device for the electric measurement of the level of a liquid in a container has a protective tube (1) within which a conductive foil (10) is arranged twisted. The protective tube is a corrugated tube with corrugations (2, 3). These corrugations (2, 3) have interruptions (4, 5, 7, 8). The interruptions lie along two helical lines (6, 8). The conductive foil (10) is pushed with its longitudinal edges (11, 12) into these interruptions (4, 5) which lie on two helical lines (6, 9). In order to permit of easy bending of the entire device, the conductive foil (10) has incisions (13, 14) which extend from both longitudinal edges (11, 12) up to the center of the conductive foil (10).

Abstract: A process and apparatus are disclosed for continuously determining the moisture content of a spoilable foodstuff, in particular, of grain and processed products of the latter, which is moved along a production line as a product stream and passed, at least in part, through a measuring section of a housing in accordance with the process, a pourable average of the product stream is created continuously within the measuring section, and the product moisture content of this product average is measured electrically on a continuous basis. In accordance with the device, the measuring housing has a capacitor as a continuous-flow measuring section and a device for continuously controlling the creation of a pourable product average. One of the central concepts of the invention is found in the interaction of the following factors: --continuous creation of a product average, continuous trickling-type flow of the product, with simultaneous electrical measurement on a continuous basis.

Abstract: An elongated capacitance probe for use in a measuring system for locating a liquid level interface in a tank is provided. The probe includes an outer casing having first and second substantially semi-circular matingly engaging portions, the outer casing having top and bottom ends defining a length thereof approximately equal to a height of the tank. Spacers are mounted in opposed relation in the outer casing to form spacer pairs, the spacer pairs located in a spaced apart relationship along a longitudinal axis of the outer casing. A plurality of ground plates are mounted in a spaced apart relationship in the spacer pairs. To locate the liquid level interface in the tank, one or more capacitor plates are mounted in the spacer pairs, each capacitor plate mounted between a pair of ground plates, and extending substantially the length of the outer casing. Each of the capacitor plates in combination with a ground plate forms a capacitor extending substantially the entire length of the outer casing.

Abstract: A method of obtaining data for mathematical characterization of a wave surface by transmitting a beam toward the surface so that the beam is reflected from an element of the surface in a direction determined by the instantaneous, two dimensional slope of the element. The reflected beam impinges on a screen as a spot whose time varying coordinates correspond to the time varying slope of the element. These coordinates are captured by scanning the screen with a raster scan which controls counters identifying the spot position. The instantaneous distance is measured by a capacitance probe to relate the captured coordinates to the corresponding angles of reflection by appropriate trigonometric relations.