Abstract: A fuel sensor for sensing a mixing ratio of a given liquid in a mixed fuel comprises a housing; a structure housed in the housing, the structure having a fuel passage formed therethrough; and an electrode assembly housed in the housing and held by the structure, the electrode assembly including at least one pair of probe portions which are exposed to the fuel passage. The full sensor also includes an output control circuit housed in the housing, the output control circuit issuing an amplified voltage output which varies in accordance with a small information signal applied to an input portion of the output control circuit; and an electrically conducting member housed in the housing and electrically connecting the electrode assembly to the input portion of the output control circuit, so that the output control circuit issues an amplified voltage output which varies in accordance with a capacitance established between the paired probe portions.

Abstract: Device for measuring the length and number of fibers in an aqueous suspension has a sensor with an upper and lower electrode with an insulating part between the electrodes, a rectifying channel having an inlet and outlet part, the first in close contact with the upper electrode, the second in close contact with the lower electrode, with mutually aligned openings of the sensor and the rectifying means. This arrangement can be applied for such suspensions of fibers or other particles, the electric conductivity of which is different from the conductivity of their carrying medium.

Abstract: A signal responsive circuit especially adapted for use in a water treatment system for signaling the need for regeneration of an ion exchange resin bed or the replacement of a particulate filter medium. A series of three electrodes are disposed in the water treatment medium in longitudinally spaced relation along the direction of flow and an alternating current signal drives the center-most electrode. The two outer electrodes are coupled as inputs to first and second operational amplifiers having asymmetrical gain characteristics. When the effective resistance between the center electrode and the two outer electrodes are equal, which is the condition prior to the movement of the hardness front or contamination front to the location of the electrodes, a first signal output condition exists.

Abstract: A salinity measuring apparatus utilizes a specialized probe with dual electrode pairs, one of the pairs being used to pass current through the electrolyte, while the other picks up voltage drop across a region in the electrolyte and feeds it back to the current producing amplifier, which adjusts the current output until a stabilized, predetermined voltage difference occurs across the voltage electrodes. The circuit which drives the current between the current electrodes produces a positive pulse, and an ensuing negative pulse, which are sequentially applied across the electrodes so that two separate measurements are made using pulses of opposite polarity to cancel out electrode polarizations. An amplifier circuit receives a pulse from the voltage source and applies it to the electrodes.

Abstract: A four-electrode open-cell conductivity sensor for measuring the conductivity of ocean water. A simplified version of the conductivity sensor may be used as a standard conductivity cell for measurement of fluid conductivity in a laboratory, or for monitoring fluid conductivity in a chemical processing plant. The sensor includes opposed electrode pairs each of which include a hemispherical current electrode and a coaxial ring-shaped voltage electrode. In operation, an alternating current is generated across the opposed current electrodes and the resultant electric field is sensed by the voltage electrodes. A feedback circuit is utilized to adjust the amplitude of the electric current generated across the current electrodes so that the inphase potential across the voltage electrodes is maintained at a substantially constant level.

Abstract: The invention is directed to an instrument for measuring the absolute electrical conductivity of liquids, which instrument may be employed on-line in a recirculating paint bath to measure the conductivity of the paint. The instrument comprises a four electrode probe and a meter which comprises a device for generating and controlling an AC current connected to the first electrode such that a constant AC voltage is maintained across the second and fourth electrodes and a device for measuring and detecting an AC current connected to the third electrode, wherein the fourth electrode is maintained at the same potential as a nearby ground.

Abstract: The apparatus has two plate electrodes surrounded by a third electrode. The third electrode is maintained at an electric potential equal to half of the electric potential between the two plate electrodes. The fluid is passed between the two plate electrodes and the changes in capacitance between the two plate electrodes is measured. From this measurement the fraction of gas in the fluid is determined.

Abstract: A soil probe, comprising, in one form, a cylindrical member of insulating material having a pair of metal, electrically conductive, ring electrodes mounted a short distance above a conical portion at the lower end of the probe, these ring electrodes lie flush with the outer surface of the cylindrical member and are spaced apart from each other by the insulating material. An electrical-electronic measuring system is connected to the electrodes by conductors providing identical line impedance for each ring. The system has an initial electronic portion inside the cylindrical member and close to the electrodes and has a second portion distant from the cylindrical member. A plurality of different frequencies of radio-frequency current is applied to the electrodes, for accurate determination of capacitance at the different frequencies. Therefrom are determined the dielectric dispersion characteristics of the soil.

Abstract: A gas chromatograph system is provided with an improved electrolytic conductivity cell (16) for detecting a selected material species in a fluid stream from conventional gas chromatograph (10, 12) having both gas and liquid phases. Planar electrodes (80, 82) are spaced by an insulator (84) and define borehole diameters (88, 90, 92) which enhance the generated signal-to-noise ratio by providing a short fluid transit time within the conductivity detecting volume compared with the effective time of the chromatographic event of interest. A pneumatic damper (108) may be further included to reduce generated system signal noise.

Abstract: An electrode (20) for electrochemical measurements in aqueous solutions at high temperatures, especially measurements in water in or from a primary or secondary circuit of a nuclear reactor in operation at a temperature of the water substantially prevailing at that time, comprises a conductor (21) of a platinum-group metal which for part of its extension is enclosed within a casing (22) making tight contact with the conductor and consisting of sintered-together particles of aluminum oxide, zirconium oxide or other electrically-insulating material which is inert to water. The conductor has one part (21a) exposed the aqueous solution and one connection part (21b) for connection to an electrical measuring member.

Abstract: This invention relates to an electrical measuring probe for determining the electrical conductivity of a liquid comprising a measuring zone extending longitudinally through the probe, through which the liquid to be measured flows and to which an electrical current is applied between electrodes, the electrodes having electrical leads remote from the liquid to be measured and those parts of the electrodes remote from the liquid to be measured forming a mechanically stabilizing and electrically conductive insertion or conductor frame of an electrically insulating sleeve which determines the shape of the probe. The insertion frame contains individual conductors in the sleeve distributed axially symmetrically in relation to the longitudinal axis of the probe, and the sleeve is made by injection-molding and consists of a chemically stable thermoplastic.

Abstract: A gas chromatograph system is provided with an improved electrolytic conductivity cell (16) for detecting a selected material species in a fluid stream from conventional gas chromatograph (10, 12) having both gas and liquid phases. Planar electrodes (80, 82) are spaced by an insulator (84) and define borehole diameters (88, 90, 92) which enhance the generated signal-to-noise ratio by providing a short fluid transit time within the conductivity detecting volume compared with the effective time of the chromatographic event of interest. A pneumatic damper (108) may be further included to reduce generated system signal noise.

Abstract: Method and apparatus of determining the dynamic surface potential of a solution, wherein a steady stream of the solution is formed, and the surface potential at a free surface of the stream of solution is measured by means of a rotary electrode that rotates in close vicinity of, but separated from, the free surface of the solution, and is mounted within an electrically grounded chamber.

Abstract: An improved probe for an alumina concentration meter is disclosed. The active anode and cathode surfaces of the probe lie on a common surface. A bath temperature measuring device is included within the probe.

Abstract: Device for activating or inactivating a liquid pump on the basis of the electrical conductivity of a liquid. Device comprises, in combination, a housing having a passageway through which a liquid can flow, a pair of conductivity-sensing electrodes disposed near or in the passageway, means for connecting the passageway to a liquid pump, and means for connecting the electrodes to a conductivity-dependent pump activator connected to the pump. Device provides through-the-probe pumping and is adaptable for manual operation or in-line liquid control.

Abstract: A liquid conductivity cell utilizing the Kelvin four-electrode system, and a circuit to operate an alarm when the operating electrodes have reached a predetermined state of fouling. Thus, the invention cell self alarms when the electrodes have fouled. The electrodes each have two flow passageways, whereby the liquid takes a "U" shaped path, and whereby the outer electrode closest to the liquid inlet and outlet fittings sinks all stray currents and the like to thereby permit interference free operation.

Abstract: A cell for measuring the conductivity of liquids flowing through the cell utilizing the Kelvin four-electrode system, plus a guard electrode, and a circuit to operate an alarm when the operating electrodes have reached a predetermined state of fouling. Thus, the invention cell self alarms when it has been fouled to the point where operating results will thereafter be impaired.

Abstract: A conductivity cell wherein thin film or foil electrodes are supported in a case or holder and are separated by an electrically insulative spacer member. A small portion of each electrode together with an exposed surface of the spacer member forms a channel in which thin films of an electrolyte may be deposited from a measured environment and with the electrodes being connected to a conductivity circuit the conductance of the thin film may be measured. If the electrolyte and its concentration are known, the film thickness and deposition rate in the channel may be obtained.

Abstract: Circuitry is disclosed for measuring the quantity of total dissolved ionized salts in an undiluted aqueous sample. A bi-level power supply operating through a square wave generator and voltage follower creates a low amplitude AC signal at a predetermined level above a ground reference. The control voltage is applied through a conductivity probe assembly to two series connected operational amplifiers operating through a bridge assembly and meter movement to provide a reading of the total dissolved ionized salts in the sample as a function of their ionization characteristics.

Abstract: A simplified clean conductivity or pH cell assembly comprising a solid plastic cell body and a test fluid conduit comprising a clean pipe fitting, affixed to the forward face of the solid body by means of an external clamp and a seal such as an O-ring. The clean pipe fitting is preferably formed of stainless steel and the internal surface thereof which comes in contact with the test fluid is plane and has no crevices or the like which could cause contamination of the fluid.Pencil shaped electrodes are fixed in said solid body and extend therefrom into the test fluid in the conduit to be measured. The face of the solid body which is in contact with the test fluid is plane with no cavities, crevices, holes, projections, restricted channels, or the like. The electrodes for conductivity or pH measurement are cleanly formed of glass or stainless steel or other suitable material and have no surfaces which might result in contamination or the collection therein of dirt and the like.

Abstract: Aggregation of blood-platelets is detected by using a test cell which contains two electrodes which extend into the sample. So as to maximize the change in resistance between the electrodes which occurs as platelets aggregate on them, they are each rod-shaped and of not more than about 0.25 mm in diameter. The resistance between the electrodes is detected using an AC signal to avoid polarization effects.The test cell may be constructed so as to be a disposable item.

Abstract: The conductivity cell consists of a first set of electrodes fixed rigidly to a second set of electrodes. Each set of electrodes has an insulating material support with an electrode well through it, and three spaced electrodes positioned sequentially within the well. In one embodiment, the support is a glass tube and the three electrodes are deposited on the inner surface of the glass tubes. In a further embodiment, the three electrodes are washer shaped conductive strips fixed within the electrode well and spaced by two washer shaped non-conductive strips also fixed within the electrode well. Each set of electrodes further includes a glass tubing fixed within the electrode well between each outer electrode and the outer end of the electrode well. In another embodiment, washer shaped electrodes are recessed in the wall of the electrode well such that the surface of the strips are flush with the electrode well surface.

Abstract: A simple, low cost test instrument for measuring effectiveness of a corrosion inhibiting film. It employs solid state integrated circuits and applies an AC signal across the film. The amplitude of the signal is less than that which would damage the film, and the electrical resistance is a measure of the inhibitor effectiveness.

Abstract: A conductometric gas analysis cell comprised of a porous Teflon membrane supporting interdigited electrodes separates a thin layer of deionized water from a gas phase to be analyzed. Volatile species in the gas phase pass through the membrane and increase the conductance of the water which results in increased current flow between the interdigited electrodes.

Abstract: An improved apparatus for evaluating the continuity of the enamel lining of metallic containers. The apparatus has been developed for quality control inspection of containers and is designed to ensure that the entire interior surface of the container is evaluated by the test. The apparatus utilizes cooperating carbon electrodes of opposite polarity, an electrolyte solution, a grounded container, an enabling circuit and a meter to measure current flow through defects or discontinuities in the enamel lining. The carbon electrodes include a primary or measuring electrode, and a short secondary or liquid sensing electrode.Electrolyte solution is added until contact is established between the primary and the sensing electrodes thereby activating an enabling circuit which is used to control the meter display.