Abstract: An electrode, preferably of a conductive polymer, has on its surface, preferably over all of its surface, an ion exchange material, preferably of significant thickness. Such a coated electrode may be used for sensing the presence or measuring the concentration of an ionic species, or for removal from or release of an ionic species into an electrode.

Abstract: A particle detector for detecting particles of blood components in an electrolyte employs a minute hole through which a fixed quantity of the material is drawn. Electrodes inside and outside the detector pass an electric current through the minute hole. When a particle passes through the hole, it partially blocks the hole, whereby a sharp change is experienced in the amount of current passing through the electrolyte. A syringe fluid path in the detector enters the fluid path for the test fluid at right angles thereto. The inside electrode is disposed in the syringe fluid path near its junction with the fluid path for the test fluid. A colorimeter is placed in series with the flow of the test fluid to measure the concentration of hemoglobin in the test fluid. Automated control of the particle detector is provided by a plurality of cams driving a corresponding plurality of pistons.

Abstract: Apparatus for measuring the electrical impedance of low conductivity samples, and particularly microbial suspensions, has a coil surrounding a tubular sample container. A capacitive pick-up on the sample wall provides an input to a variable gain amplifier driving the coil. The resident frequency of the circuit is measured to provide an indication of sample conductivity.

Abstract: For the measurement of gas, vapor, or aerosol fractions of a measured gas, the fraction to be determined is absorbed in a reaction solution, and a change of resistance from a reaction between the fraction and the reaction solution is determined as the measured variable by an ohmmeter, using electrodes in the reaction solution. The measured gas entering a test container through a sealing unit tight to the reaction solution and passing the medium to be determined, is improved with regard to all-purpose use and convenient measurement. This is done pursuant to the invention by placing the reaction solution in a disposable test container that can be inserted or connected interchangeably to the measuring device which has electrodes. The test container is sealed, at least at one end, with a sealing unit that is permeable to the medium to be determined and impermeable to the reaction solution.

Abstract: A method for the automatic line calibration of an electrochemical sensor for measuring the concentration of a liquid phase dissolved electrochemical substance flowing into a pipe and is characterized by the following stages: upstream of the electrochemical sensor, a generator is placed on the pipe, the generator being suitable for delivering standard quantities of the substance; between the generator and the electrochemical sensor, a delay line (3) is placed on the flow with a given volume of this liquid. By way of the generator, successively injected into the liquid pipe are two bursts of known quantities of the electrochemical substance corresponding to the concentration C.sub.1 and C.sub.2 in the liquid flow. From the indications of the electrochemical sensor (4), the delay time introduced by the delay time is determined.

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: A tissue testing chamber having a hollow, electrically insulative housing separable into two parts or halves, each half including a plate-like working electrode and spaced therefrom an annular measuring electrode, with electrical leads provided to each of the electrodes for interconnection with external control and measuring equipment. Each housing half or test chamber half has a cavity communicating with both the working and measuring electrodes and an open end. The housing halves clamp the test specimen between them. A quantity of Ringer's solution is added to each housing cavity and the four electrodes are then connected in a four electrode impedance bridge with selectively variable impedances (e.g., capacitance) which on bridge balance provides capacitance of specimen.

Abstract: A hermetically sealed, electrically insulative enclosure (A) is surrounded by a Faraday cage (B). At least one electrode (C) is disposed within the hermetically sealed enclosure. The volume of the enclosure is selectively altered such that an initial charge density in the neighborhood of electrod changes, which changes the electrode potential. The change causes a current to flow to or from the electrode which returns the electrode potential and the electrode surrounding space charge toward an equilibrium condition. In one embodiment, a current measuring circuit (D) is disposed between the electrode and the Faraday cage to derive a measure of the current flow therebetween. In another embodiment, a like electrode is disposed within another hermetically, sealed insulative enclosure which is shielded by the same or another Faraday cage. In the second embodiment, the measuring circuit measures the current flow between the two isolated electrodes.

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: An electrical conductivity testing device for detecting mastitis in dairy cows includes an inlet for receiving a sample of milk to be tested, a conductivity cell having a milk flow-through testing passage in flow communication with the inlet, and a milk discharge outlet in flow communication with the conductivity cell, so that a milk sample enters the inlet, flows through the conductivity cell, and flows out through the discharge outlet. The flow described may be continuous or may be discontinuous so that the sample is held in the conductivity cell at least during taking of the conductivity measurement. The conductivity cell is arranged so that it is completely filled with milk during the taking of conductivity measurements. Electrical circuitry is provided to produce an electrical signal proportional to the conductivity of the milk in the conductivity cell.

Abstract: A conductivity cell is presented having a solid inner electrode and a hollow electrode whereby the inner electrode is adjustably mounted. The adjustable feature allows the cell to be accurately calibrated for various fluids having a wide range of conductivities.

Abstract: A cell for remotely sensing conductivity of a fluid passing through it, the cell having an inlet and an outlet and two fluid paths between the two, thereby defining a fluid loop, an excitation transformer comprising a first toroidal core having a hole through it and wire turns around it, the core encompassing a portion of the fluid loop therein, and a sensing transformer comprising a second toroidal core having a hole through it and wire turns around it, the core encompassing a portion of the fluid loop, the cores being coplanar to thereby reduce leakage between the transformers.

Abstract: A method and apparatus for improving the quality of an emulsion explosive composition by selecting an electrical characteristic of the composition, establishing a predetermined range of values therefor, measuring the selected characteristic of the composition and, in response to a measured characteristic outwith the predetermined range, diverting, or treating the composition to restore the selected characteristic to within the predetermined range.Suitable characteristics include conductivity and capacitance, and the technique may be employed in a static location or on a mobile carrier.

Abstract: An on-line calibration system for calibrating chemical monitors which monitor a selected chemical characteristics of a fluid sample stream, including a conditioning system for conditioning an influent fluid sample stream to produce a conditioned fluid sample stream having a predetermined level of the selected chemical characteristic. By exposing a sensor of the monitor to the conditioned fluid sample stream and calibrating the response of the sensor with respect to the predetermined level of the selected chemical characteristic in the conditioned fluid sample stream, this calibration system eliminates the effects on the response of the sensor of any ionic species in the fluid sample stream which do not affect the chemical characteristic being monitored.

Abstract: Hematocrit level of a blood sample is measured by flowing the sample along a liquid flow path and using electrodes in the flow path to obtain electrical signals representative of the sample's electrical conductivity and of the concentration of an ion species in the path, either before or after the sample measurement. Electrical signals are obtained for standardizing solution conductivity and ion species concentration. A tentative sample hematocrit value is derived from the sample and standardizing conductivity signals. Then the tentative hematocrit value is corrected with reference to the sample and standardizing ion concentration signals and to the known standardizing solution ion concentration value. A control solution of the ion species at known concentration is used for evaluating the hematocrit detection apparatus; the solution also includes an ion activity enhancing agent.

Abstract: A measuring apparatus for measuring the number and size of impurities such as dust and bacteria in super-pure water includes a sealed container; a sample supply line which sealingly interconnects a source of super-pure water with the sealed container and supplies a sample mixture of super-pure water and electrolyte to the sealed container; an overflow pipe which sealingly connects with the side of the sealed container; a negative electrode which extends into the sample mixture in the sealed container; a hollow sensor which extends into the sample mixture in the sealed container, the hollow sensor containing a positive electrode surrounded by electrolyte and having a small hole at its lower end; and a detecting circuit connected to said negative and positive electrodes for supplying a certain DC current therebetween and detecting voltage pulses caused by impurities passing through the small hole into the hollow sensor.

Abstract: A high sensitivity conductivity detector for ion chromatography includes an isolated fluid cell and a measuring circuit including an operational amplifier having its input connected to the center tap of a transformer. Feedback from the operational amplifier maintains the center tap at virtual ground potential. The excitation voltage for the transformer is supplied by two operational amplifiers. A thermoelectric semiconductor device maintains the temperature of the sample cell at a constant, ambient temperature.

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: Apparatus for measuring electrical potential in a cell, especially at a point close to a sample electrode, comprises an accommodation for a reference electrode, a modified luggin tube, elements for locating the sample electrode, and supports for both the luggin tube and the locating elements, respectively, the supports being fixed relative to each other. The apparatus requires less skill in the positioning of the sample electrode close to the point at which electrical potential is measured and is less vulnerable to inadvertent disturbance.

Abstract: An electrode probe assembly for monitoring and finding fault in the glass lining of metal vessels, pipes or the like, characterized by a cup-shaped electrode with an insulated stud inserted through a hole in the wall of a mounting member. An insulating gasket insulates the electrode from the member. Resilient means bias the cup-shape electrode against the gasket preventing leakage due to shrinkage of the gasket. Electrical connection of an insulated circuit is made to the stud.

Abstract: An electrode system for voltametric measurements for measuring oxidative and reductive compounds in aqueous solutions primarily in the paper and pulp industries, said system comprising a working electrode (1), a counter-electrode (2) and a reference electrode (3), these being connected to a voltametric measuring apparatus (4). The aim is to introduce an electrode system mountable in the process pipeline with greater ease than electrodes of prior art and of a construction simpler than earlier systems, and more durable and less maintenance-requiring than these.As taught by the invention, the reference electrode (3) is a metal electrode and has been made for instance of silver, platinum, gold, titanium or "Hastalloy C" steel. The electrodes are advantageously installed together and in one and the same pick-up and disposed to be so placed in the process pipe system that the solution flowing in the pipe system flushes the electrodes.

Abstract: A method for measuring the purity of water in which the water is passed through an insulated pipe (1) in a cell spaced between electrodes (2-3) for measuring the tribo-electric electromotive force (e) generated by the flow, and wherein the resistivity of the water is calculated from the measured electromotive force.

Abstract: The present invention relates to a wheel electrode suitable for use with a device for making an electrical survey of a structure contained in an electrolyte. The wheel electrode includes a chamber which contains electrolytic solution and a porous rim. The rim includes a dielectric rim structure having at least one recess in its axial surface, a plurality of apertures passing through the rim structure into the recess, and at least one porous member securable in the recess and having a predetermined rate of permeation. A metal electrode is positioned in the chamber in contact with the electrolytic solution. An elastic porous rim cover is securable about the rim for making contact with the electrolyte. The rim cover is adapted to carry an electrically conductive solution to the electrolyte during wheel rotation. Generating mechanisms are spaced about the wheel electrode at predetermined intervals for generating a series of electrical signals as the wheel electrode rotates.

Abstract: The new instrument for taking readings of the hematocrit value from a blood sample has two electrodes with which the conductivity of the sample may be measured. The sample contacting faces of the electrodes are placed in a horizontal plane with an accurately fixed spacing therebetween so that a blood column of a given size may be formed from the sample. The sample is acted upon by ac. From a reading representative of the change in impedance the hematocrit value may be read off from a calibration curve.

Abstract: In the formation of a paper web from stock fed to a Foudrinier wire, the Zeta Potential is an important parameter. A measure of Zeta potential is made by measuring the streaming potential developed in a vertically-arranged cell having a horizontal mesh therein on the underside of which a pad of fibres and fines is formed by pumping stock into the lower part of the cell. Electrodes located in the cell above and below the pad are used to obtain a measure of streaming potential at a given pressure differential across the pad. A pressure transducer is mounted in the lower part of the cell. Corrections are made for temperature and conductivity by sensors in the stock feed path to the cell. A microprocessor control and measuring circuit is disclosed which sequences valves for controlling the flow of stock and flushing fluid to the cell and which measures the relevant parameters.

Abstract: Rapid and accurate whole blood analysis measurements are made with analysis systems of the potentiometric type that employ restricted diffusion type liquid junctions where the whole blood sample is flowed past sensing electrode and liquid junction at a velocity of at least one centimeter per second during a data acquisition interval that is at least twenty-five milliseconds in duration.

Abstract: The salinometer is based on a direct determination of the conductivity ratio R.sub.t =(Cx/Cs).sub.t of sample water to standard seawater in a two channel, dual-cell, continuous-flow system. Each of the channels includes a conductivity cell with four electrodes immersed in sequence in the water flow. Two of the electrodes are current electrodes and the other two electrodes are potential electrodes. The standard water and the sample water pumped into their respective channels, are maintained at a common temperature by heat exchangers and a common bath. The salinometer circuitry include a first current source for driving a controlled current into the current electrodes of the conductivity cell to maintain a constant voltage across the potential electrodes. A second current source drives a current which is a linear function of the first controlled current into the current electrodes of the conductivity cell in the reference channel. The conductivity ratio R.sub.

Abstract: A liquid conductivity monitoring device includes an elongated cylindrical housing having parallel-spaced electrodes at one end for insertion into a liquid carrying conduit, and a transparent user-viewable lens at its other end. The electrodes are connected within the housing to a differential amplifier which provides a change in output signal level when the liquid conductivity exceeds a predetermined threshold level. A pair of oppositely-poled LED's of different colors connected between respective unidirectional current sources and the output of the differential amplifier and viewable through the lens indicate acceptable and unacceptable conductivity levels to the user.

Abstract: A method of measuring ion concentrations in solutions comprises using at least two ion sensitive test electrodes in the solution to be measured, the test electrodes having different sensitivities only in respect of the ion or ion mixture to be measured, setting the operating point of the test electrodes by means of at least one common reference electrode, and evaluating the signals of the test electrodes to produce a measurement result essentially independent of the properties of the reference and test electrodes which would interfere with accurate measurement.The invention also includes apparatus suitable for carrying out the method.

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: A reference cell for conducting closely spaced buried structure-to-soil electrical surveys uses a soil contact cell adapted to be mounted on the lower end of a pole or cane to be held by the surveyor walking over the right-of-way of the buried structure such as an underground pipeline. The cell includes a fluid chamber on the lower end of the pole or cane and includes on the lower end of the chamber a ground contact pad. A spring loaded bottom wall or boot closes the chamber and is operative to reduce the volume of the chamber when the lower end of the chamber is forced by the pole into contact with the ground above the buried structure. The reduction in volume of the chamber forces fluid through the contact pad to the ground to insure good electrical contact. Fluid in the chamber may be continuously replenished by a make-up supply carried by the surveyor which is drawn from the supply by return of the boot to its unstressed state.

Abstract: A process and apparatus for monitoring the concentration of electrically conductive solid particles in suspension in a fluid by circulating the fluid between a pair of electrodes opposed surfaces disposed at a fixed distance from each other, the electrodes being connected across a DC power supply. Electrical discharges occur across the gap between the electrodes, and the concentration of solid particles is determined as an inverse function of the average delay time interval required for triggering the electrical discharges, which is in turn measured by counting the number of electrical discharges occurring within a predetermined time interval.

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: A method and apparatus for measuring a chemical characteristic of a liquid such as its hydrogen ion activity or pH value. A disposable cassette having a reference and indicating electrode therein utilizes the same solution to first calibrate the device and then as an electrolytic bridge from the liquid sample to the reference electrode. The solution has the properties of a buffered pH and also provides a stable electrochemical environment around the reference electrode. In one embodiment, a volume of a liquid sample is placed into a capillary tube and the open end of the tube is then placed over the indicating electrode immersed in the solution. The electrical potential between the indicating electrode and the spaced reference electrode in the electrolyte solution provides a measurement of the pH value of the liquid when compared to the calibration potential previously measured without the liquid sample contacting the indicating electrode.

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: A method and apparatus wherein a sample of gas or fluid containing carbon dioxide in the form of dissolved carbon dioxide gas, bicarbonate ion, and/or carbonate ion is injected into an extraction chamber provided with an acid extracting fluid. A carbon dioxide-free gas stream is passed through the extraction chamber in order to carry the dissolved CO.sub.2 gas formed from bicarbonate and carbonate ions, as well as that already present, onto a spiral absorbing column, wherein a dilute alkaline solution absorbs the CO.sub.2 with a resulting change in electrical conductivity of the alkaline solution. The system disclosed provides electrical means for measuring the conductivity difference thus produced, means for conversion of this difference to an appropriately coded electrical signal, and means for providing a direct display of the sample concentration. Means are provided for indicating when a sample is being processed by the apparatus, and for holding the displayed concentration until manually re-set.

Abstract: A safety valve for exposing a measuring probe to a fluid comprising a hollow inner valve body with a valve seat movably positioned within a hollow outer valve body having a cooperating valve element for providing fluid-tight engagement when the valve is closed. The inner valve body partially extends from the outer valve body when the valve is open for passage of the fluid into an inner chamber for exposing the inserted probe to the fluid. The probe is secured to the inner valve body by a threaded cap, the movement of which is translated to the inner valve body in the presence of the probe for moving the inner valve body to the open valve position. The valve is prevented from being opened in the absence of the probe by a spring mounted on the outer valve body engaging a catch on the cap for restricting movement thereof preventing the valve from being opened.

Abstract: A measuring circuit for use with an active polarized electrode, a reference electrode and a diaphragm which separates the solution to be examined from the electrolyte in which the electrodes are immersed. The output signals from the polarized electrode and from the reference electrode are processed as follows. The respective electrode is connected to one of the inputs of a respective operational amplifier (OA1, OA2) which serve as current voltage converters. The outputs of these amplifiers are then connected to a third operational amplifier (OA3) which detects the prevailing current difference in the electrode currents and initiates a necessary correction.

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: A liquid testing kit for determining the pH value of a liquid body at various depths includes a pH tester and a liquid sampling container having a spring-hinged lid. The container is adapted to be lowered to various depths with the lid in open position. The hinge is then remotely triggered to close the lid at the desired depth whereupon the container is removed from the liquid body. A self-seating ridged planar seal is employed between the lid and the container. The removed container can be stood upright, and a plurality of vertical internal supporting webs are dimensioned so as to accommodate a pH test instrument in the container. The hinge includes a crank arm having a support post against which a closing or opening tensile force is applied. The crank arm is pivoted from a first position wherein the tensile force creates an opening moment to a position wherein the post lies on the opposite side of a pivot so that a tensile force at the same post creates a closing moment.

Abstract: There is disclosed an apparatus for diagnosing milk secretion disorders in animals such as cows. The apparatus is based upon an electric detection of deviations from the properties of a standard milk secretion, and comprises a holder carrying a diagnostic dish divided by partition walls into a number of diagnostic units corresponding to the number of teats of the animal. The diagnostic units are each provided with a measuring probe exposed to the mouths of scavenging nozzles and with a circuit for evaluating the milk quality as by its electrical conductivity. The outlet of said circuit is connected to the inlet of a display indicating, for example, when the quality of the milk in each diagnostic unit exceeds a predetermined value.

Abstract: A conductivity probe having a cylindrical body with an annular open-sided groove in which the electrodes are disposed, and a sliding cover wall for the groove biased to a position covering the groove but easily operable with one hand to slide the cover so as to open the groove. Viscous or slurried material can easily enter the groove, be trapped and confined for the conductivity measurement and then readily washed from the groove and surrounding parts for the next operation.

Abstract: A combination process sensor for use in electrically non-conducting lined steel vessels has a tantalum body containing a temperature sensitive element. One end of the body is positioned to be in contact with a product undergoing a process in the tank. Upon this end of the body there is fabricated an electrode, which allows the galvanic sensing of any faults which may occur in the glass lining.

Abstract: An electrochemical reference cell has a reference electrode disposed at one end of a rigid hollow cylinder immersed in an electrolyte solution of known concentration. Different interlocking series of plugs, consisting of a material such as wood, with semipermeable, longitudinally extending capillaries, are fitted together in abutting relation to fill the hollow interior of the cylinder between the reference cell and the other end with one series longitudinally overlapping the other. The abutting end surfaces of adjacent plugs in each series are sealed to close off the capillary path between successive plugs, whereas the outer surface of the last plug in at least one series is left unsealed to be in contact with the test solution, so that circuitious ion transfer path is established between the reference cell and the test solution that passes tranversely through the longitudinal semipermeable capillary walls from the plugs in one series through adjacent plugs in the other.