Abstract: A measuring probe for measuring in ground a parameter, the probe having an elongate body with a tip as a leading end and a head as a trailing end, the elongate body having a first and a second member which each extend in a longitudinal direction of the elongate body, the second member provides resistance against bending of the first member when the tip is advanced into the ground by hammering on the head.

Abstract: A sensor structure is disclosed comprising at least four planar layers subsuming at least one cavity housed but not contained by overlapping apertures through at least two of the planar layers, wherein the at least one cavity comprises a plurality of chambers, and wherein at least one chamber of the plurality of chambers is configured to be in fluid coupling with at least one other chamber. The plurality of chambers may be defined by overlapping apertures through a plurality of the planar layers. The plurality of chambers may include a Gas Chromatograph (GC) column. The planar layers may be flexible flat glass. The planar layers may be fused together. The layers may be made with apertures through the layers disposed in a desired pattern to define complex structures by the apertures overlapping between abutting layers when the layers are stacked. The planar layers may be configured to admit ultraviolet light.

Abstract: The disclosure relates to a method of analyzing at least a rock sample extracted from a geological formation. The method comprises: heating the at least one rock sample under inert atmosphere with a temperature below 300° C. and with a flow of inert gas to remove contaminants, analyzing at least one of the decontaminated rock samples and determining at least a property relative to non-volatile organic matter contained in the geological formation based on the analysis.

Abstract: An apparatus and a method for extracorporeal blood treatment, especially for hemodialysis, wherein blood of a patient is flushed with a dialysate in a dialyzer and wherein a variable correlated with the plasma sodium concentration of the blood is measured. The composition of the dialysate then is adjusted in response to the variable measured so that the plasma sodium concentration of the blood at least at the end of the blood treatment has the same value as at the beginning. For measuring the variable correlated with the plasma sodium concentration of the blood, for example a bypass operation can be implemented in which the dialysate is guided past the dialyzer so that a residual volume on the side of the used dialysate at least partially adopts the concentration of the substances dissolved on the blood side.

Abstract: The present patent application relates to a device (1) for measuring the conductivity of a liquid, which comprises a measuring chamber for containing a sampling volume to be irradiated with UV rays formed in a hydraulic body (4) which comprises an inlet channel for feeding the measuring chamber with liquid to be measured and an outlet channel for removing the measured liquid from the measuring chamber, the inlet channel and the outlet channel emerging on either side beyond a surface exposed to the UV rays, such that only the sampling volume contained in the measuring chamber is irradiated. The present patent application is also directed towards a use of such a device and to a purification system comprising such a device.

Abstract: A medical needle comprising a flat puncturing part having front and back surfaces that are parallel to each other, wherein the puncturing part comprises a pair of side-surface inclined parts and provided at tips of respective side surfaces and a front-surface inclined part provided at a tip of the front surface, the pair of side-surface inclined parts and the front-surface inclined part each extend in an inclined manner relative to a puncturing direction so as to be tapered, and the tip of the front-surface inclined part adjoins a blade edge part formed by adjoining the tips of the pair of side-surface inclined parts and a depression is formed in the front surface of the puncturing part so as to partially indent the pair of side-surface inclined parts and the front-surface inclined part.

Abstract: A sensor for measuring conductivity of a fluid containing dissolved ions, particularly for measuring conductivity of salt water, features a cylindrical tube (57) of poorly conductive material such as glass, a first electrode (51A) and a second electrode (51B) inside the tube, connected together (56) to maintain a common electrical potential, a first transformer (52,53) concentrically arranged around the tube (57) to drive current through the fluid in the tube, and a second transformer (54, 55) arranged to sense a value of the current flowing in the fluid, and a digital processing circuit (62) coupled to receive an output signal of the second transformer, and to derive therefrom a value representing the conductivity of the fluid. The sensor is adapted to be towed behind a research ship, or to be deployed on an autonomous underwater vehicle (AUV) or the like. Current signals are preferably processed by digital switching measurement technology (dMST).

Abstract: A conductivity detector includes a flow channel, an electrode arrangement, and a detector. The flow channel has a tube shape with a channel diameter through which a solution including ion components flows. The electrode arrangement is on the flow channel and includes at least an anode and at least a cathode. The anode and cathode are spaced apart by an electrode gap less than or equal to the channel diameter. The detector is connected to the electrode arrangement to detect electrical conductivity of the ion components.

Abstract: A method is provided for determining the amount of ammonia which is stored in a storage container by a chemical bond to a solid storage medium, in particular a salt of an earth alkaline metal or the like, and which can be released by supplying heat in order to be supplied to a catalytic exhaust gas purification device of an internal-combustion engine. The storage medium functions as a dielectric of an electric capacitor and the stored amount of ammonia is inferred from the capacity of this capacitor. One wall of the housing of the storage container functions as a first electrode of the capacitor, and, within the storage container, at least one additional electrode is arranged such that at least a partial amount of the storage medium forms the dielectric. The storage container may have an essentially cylindrical shape. Several cylindrical electrodes can be arranged in a coaxial manner.

Abstract: Measurement devices, systems, and methods to measure a high field conductivity of a fluid are provided herein. The measurement device includes a fluid cell, a pair of electrodes, a voltage switch, and a measurement unit. The fluid cell is on an inclined plane to receive the fluid. The pair of electrodes are connected to the fluid cell. The pair of electrodes are spaced apart from one another to receive the fluid therebetween and positioned parallel to one another to pass an electrical current therethrough. The power unit provides a high voltage power supply to one electrode of the pair of electrodes. The measurement unit measures the electrical current that passes between the pair of electrodes through the fluid.

Abstract: A fryer measures cooking medium quality, and includes a cooking vessel configured to store a cooking medium, an electrode plate completely immersed in the cooking medium, an insulator comprising a first side and a second side, wherein the first side of the insulator is fixed to the electrode plate, and a second side of the insulator is attached to a wall of the cooking vessel, a guard ring fixed to the cooking vessel and surrounding the electrode plate and insulator. The guard ring extends further away from the wall of the cooking vessel than the electrode plate. A size of a gap between the guard ring and the electrode plate is based on a height, a width, and a thickness of the electrode plate and substantially defines a gain of the electrode. A signal conditioning circuit measures the conductivity of the cooking medium applied to the electrode.

Abstract: A tissue monitoring system includes an introducer having an inflatable section and a plurality of electrodes disposed thereon. The electrodes are alternatively connected to an electrode contact system which includes at least one signal line and at least one measurement line for taking readings about a circumferential segment of tissue encompassed by the electrodes.

Abstract: The measuring device has at least one measuring probe, e.g., a physical or electrochemical measuring probe, which is equipped with one or more memory units and which is connected through a cable, e.g., a coaxial cable, to a transmitter which includes a processor. The measuring probe has a ground wire and is connected to the memory unit through a first signal wire, wherein under the control of the processor in accordance with a transmission protocol, the first signal wire and a connecting cable serve for the unidirectional transmission of the analog or digital measuring signal of the measuring probe as well as the preferably bidirectional transmission between the measuring probe and the transmitter of digital operating data which are read from or to be written into the memory unit.

Abstract: This invention relates to a device of electrodes for measuring water content in foundry sand, an apparatus for measuring water content in foundry sand, and a method and an apparatus for supplying water to a sand mixer. When the prior art device for measuring water content in the foundry sand is disposed in it, the size or shape of the device of the electrodes is limited.

Abstract: A test strip and analytical apparatus have pin connections permitting the definition of geographic regions or of particular customers. A test strip made for use in a particular region or for a particular customer will have pin connections matching features of the apparatus made for use in that region or by that customer. Insertion of the strip into the apparatus does not merely turn on the apparatus, but provides the regional or customer coding. Analog switches within the apparatus allow coding of a larger number of distinct regions or customers than would otherwise be possible, all without degrading the quality of the measurements made of the fluid being tested. Conductive paths in the strips permit testing the strips during manufacture so as to detect quality lapses regarding the printing or deposition of the paths.

Abstract: A fluid detection cable is described for use in detecting the presence of leaks in areas where a particular fluid is not desired. Sensing leads in the fluid detection cable have a center conductor that may be surrounded with a non-porous conductive polymer coating that protects the conductors from corrosive fluids. A non-conductive polymer at least partially surrounds the sensing leads so that a fluid transmission path allows fluid to contact the conductive polymer. The non-conductive polymer may be porous to provide a fluid transmission path. Fluid transmission paths may also be structurally formed in the non-conductive polymer. The non-conductive polymer protects the sensing leads from false alarms that would occur if the conductive polymer were to be in contact with non-fluid conductive surfaces. The cable may also include monitor leads that are conductors coated with, or embedded in, non-conductive non-porous polymers.

Abstract: A fluid detection cable is described for use in detecting the presence of leaks in areas where a particular fluid is not desired. Sensing leads in the fluid detection cable have a center conductor that may be surrounded with a non-porous conductive polymer coating that protects the conductors from corrosive fluids. A non-conductive polymer at least partially surrounds the sensing leads so that a fluid transmission pat allows fluid to contact the conductive polymer. The non-conductive polymer may be porous to provide a fluid transmission path. Fluid transmission paths may also be structurally formed in the non-conductive polymer. The non-conductive polymer protects the sensing leads from false alarms that would occur if the conductive polymer were to be in contact with non-fluid conductive surfaces. The cable may also include monitor leads that are conductors coated with, or embedded in, non-conductive non-porous polymers.

Abstract: A method and apparatus for evaluating and improving the properties of fluid formulations is disclosed. The inventive concept employs impedance spectroscopy (IS) measurements and data analyses to determine IS parameters of fluids representative of a fluid formulation. Correlations are determined between the IS parameters and the properties of the fluids, and a modified or new fluid formulation may be developed responsive to the correlations.

Abstract: The invention relates to a fluid conductivity measuring cell having two cylindrical and coaxial electrodes mounted head-to-tail and axially overlapping on the same insulative body, the inner electrode, penetrating partly into the at least partly hollow outer electrode has a recess in which the two electrodes are accommodated to form two cylindrical spaces, one of which is an external space formed between the internal wall of the recess and the external wall of the outer electrode and the other being an internal space formed between the external wall of the inner electrode and the internal wall of the outer electrode, the external space establishing communication between a fluid inlet and a fluid outlet of the cell, each discharging into the recess and being in fluid communication with the internal space that is surrounds, this internal space serving as a conductivity measuring area.

Abstract: A device and method for measuring clotting times in a fluid, typically blood, within a microchannel, with the onset of clotting being determined by measurement of the rate of change, or the value, of capacitance or impedance between two electrodes situated on either side of the microchannel. The device includes an upper support member and a lower support member with a microchannel formed therein. The device also includes electrodes situated along the length of the microchannel.

Abstract: A sensor includes primary and secondary toroids disposed in spaced, coaxial relation to one another with a process flow path extending therethrough. Electrically conductive and non-metallic connectors are located at opposite ends of the flow path to physically contact the process fluid flowing therethrough. The primary toroid is configured to induce an electric current in the process fluid as the process fluid passes through the flow path, wherein the current varies with conductivity of the process fluid. The secondary toroid is configured to detect the electric current in the process fluid as the process fluid passes through the flow path, the current being proportional to the conductivity of the process fluid.

Abstract: A highly sensitive biosensor that uses a smaller amount of sample for measurement is described. The biosensor includes a first insulating base plate having a working electrode, a second insulating base plate having a counter electrode opposed to the working electrode, and a reagent layer containing at least an oxidoreductase. The biosensor further includes a sample supply pathway formed between the first and second insulating base plates, where the working electrode, counter electrode and reagent layer are exposed to an inside of the sample supply pathway, and the distance between the working electrode and the counter electrode is 150 ?m or less.

Abstract: A process for producing a thermoplastic resin composition is disclosed and comprises melt-kneading a resin composition containing from 40 to 90 parts by weight of (A) a polyamide resin, from 5 to 50 parts by weight of (B) a polyphenylene ether resin, from 5 to 30 parts by weight of (C) an aromatic vinyl compound-aliphatic hydrocarbon copolymer and from 0 to 30 parts by weight of (D) a polyolefin resin, per 100 parts by weight in total of the components (A), (B), (C) and (D), and further containing from 0.01 to 1.5 parts by weight of (E) an &agr;,&bgr;-unsaturated carboxylic acid or a derivative thereof per 100 parts by weight of the component (B), wherein the components (B), (C) and (E) are added from the upstream end of a melt-kneading machine and the component (A) is added part-way through the melt-kneading machine.

Abstract: A microelectrode system suitable for use in preparative and analytical chemistry having a laminated structure with one or more apertures. In one embodiment a microelectrode system (1) comprises alternating layers of conductor (3) and dielectric (or insulator) (4). The laminated structure (2) comprises two conductor layers (3) and two dielectric layers (4) formed on a base (5) of silicon or a polymeric material. The conducting layers (3) form electrodes in the microelectrodes system (1). The laminated structure has formed within it an aperture in the form of a well (6) being open at one end (7) and closed at the opposite end (8). In another embodiment, the apertures take the form of through holes.

Abstract: A conductivity sensor (16) and control circuit (18) for determining the conductivity of a fluid is provided. Conductivity sensor (16) is formed of a first annular electrode (24) spaced apart from a second annular electrode (26) having a tubular portion (28) therebetween. The first annular electrode (24) and the second annular electrode (26) are coupled to a control circuit (18). The control circuit (18) preferably includes a square wave generating circuit (40), a current-to-voltage converter circuit (42) coupled to one of the electrodes, a buffer circuit (44) coupled to the other one of the electrodes, a synchronous detector circuit (46). The synchronous detector circuit (46) is operated using the square wave from square wave generator circuit (40). By oscillating between a negative and positive gain, a constant direct current output corresponding to the conductivity of the fluid between the first annular electrode and second annular electrode is provided.

Abstract: A cable suitable for detecting the presence of corrosive liquids is disclosed. In an embodiment the cable includes two sensing wires wrapped around a core member, at least one of the sensing wires being surrounded by a non-conductive surface layer. In an alternate embodiment the cable includes two sensing wires wrapped around a core member, the sensing wires and core member being encapsulated by a non-conductive surface layer. Preferably, the cable includes insulating wires for detecting the location of a leak. When a corrosive liquid contacts the sensing wires of the cable an electrical connection is created between them.

Abstract: A conductivity sensor configuration which has essentially no external electrical field so that the calibration of the sensor is not affected by the existence of nearby external objects or fouling on the exterior parts of the sensor. Additionally, the sensor is relatively insensitive to electrode fouling or electrode polarization. The sensor includes a tube through which the liquid to be measured flows. An inner electrode plate extends partially along the length of the tube dividing the central portion of the tube into two sections. Two inner electrodes are located on the inner wall, one on each side, and two outer electrodes are located on the inside of the tube opposite the inner electrodes.

Abstract: A conductivity sensor configuration which has essentially no external electrical field so that the calibration of the sensor is not affected by the existence of nearby external objects or fouling on the exterior parts of the sensor. Additionally, the sensor is relatively insensitive to electrode fouling or electrode polarization.

Abstract: A sensor apparatus and electrode configuration within the sensor apparatus for measuring electrical characteristics of an aqueous fibrous composition. The electrode configuration includes an elongated ground electrode and at least one segmented electrode to form an array of measurement electrode cells. The electrode configuration further includes an array of reference electrode cells formed by a plurality of reference electrodes built into the array of measurement electrode cells. The measurement electrode cells and reference electrode cells have a different sensitivity to water weight of the aqueous fibrous composition and the same sensitivity to conductivity of the aqueous fibrous composition. The measurement apparatus obtains simultaneous resistive measurements from both measurement and reference cells and determines the ratio of the measurements such that the affects from conductivity is canceled out of the measurement ratio.

Abstract: A inductive conductivity sensor for measuring conductivity of a fluid includes a housing supporting a controlled impedance loop and a transducer. The transducer includes a driver for inducing a first current into the fluid adjacent the housing, and for inducing a second current into the controlled impedance loop. The transducer further includes a detector for inductively measuring the first and second currents.

Abstract: An orientation sensor especially suitable for use in an underground device is disclosed herein. This orientation sensor includes a sensor housing defining a closed internal chamber, an arrangement of electrically conductive members in a predetermined positional relationship to one another within the chamber and a flowable material contained within the housing chamber and through which electrical connections between the electrically conductive members are made such that a comparison between an electrical property, specifically voltage, of a first combination of conductive members to the corresponding electrical property of a second combination of conductive members can be used to determine a particular orientation parameter, specifically pitch or roll of the sensor.

Abstract: A method and apparatus are set forth which enables a gas chromatographic column output to be connected with a pulse discharge chamber in which chemically bound chlorine in volatile organic or inorganic samples is measured. A spark discharge is formed in the chamber to ionize and excite helium molecules to a metastable state. In turn, that transfers excitation to a trace of krypton gas in the chamber which is ionized, and the ionized krypton then preferentially binds with chemically bound chlorine. The latter binding occurs with the liberation of a photon centered at about 222 nanometers thereby defining a spectral region of interest which is measured by a photomultiplier tube to quantify chemically bound chlorine.

Abstract: An on-line sensor for measuring volumetric concentration or percent solids of a slurry flowing in a pipeline includes a section of composite or dielectric pipe connected in the pipeline, with a plurality of sensing electrodes mounted around the periphery of the composite pipe having their inner ends in contact with the slurry flowing therethrough. Preferably the inner ends of the sensor electrodes are flush with the inner pipe wall surface. An electrical signal is applied to a bridge circuit that is connected to successive pairs of sensor electrodes around the periphery of the sensor and the ratios of the local conductivity between adjacent pairs of sensing electrodes to the conductivity between a pair of reference electrodes in contact with the liquid are measured and are used to compute the local slurry concentration between adjacent pairs of sensing electrodes.

Abstract: A scour probe assembly comprises an elongated rigid tubular member of eleically insulative material, an anchoring structure fixed to a distal end of the tubular member, and a signal transmission device mounted on the tubular member. A pair of substantially parallel electrically conductive sensor lines are fixed to an external wall of the tubular member and extend along at least a portion of an axial length of the tubular member from a closed proximal end toward the distal end and extend through the closed proximal end to an interior of the tubular member. Electronic components are disposed in the interior of the tubular member and are interposed between ends of the sensor lines in the interior of the tubular member and the signal transmission device mounted in the tubular member.

Abstract: A conductivity cell for use in determining ionic concentrations in the gap between two semiconductor substrates or wafers. The wafer gap conductivity cell is composed of two flat electrodes separated by a fixed gap. The electrodes are fabricated from wafers of the same type and dimensions used as semiconductor device substrates. All or a portion of the surfaces of the wafer electrodes are coated with a conductive material. The wafer gap conductivity cell is placed in a wafer cassette or other suitable wafer holder, whose other slots are filled with wafers which are to be cleaned or subjected to another fabrication process. The cell can be used to characterize the processes used during the fabrication of semiconductor devices and assist in investigating the effect on the processes of different process vessel designs.

Abstract: Method and apparatus for determining deterioration of e.g. lubricating oil by measuring the electrical properties of a polymeric matrix (support) holding charged ionic groups. The dynamic range of the device is increased by creating a local polar environment formed around the charged groups of the polymeric matrix and by exploiting bead shrinkage with increasing degradation (or solvent polarity). Both approaches can be further employed in a single sensor by the use of multiple chambers containing a combination of the above. Also, contaminant detection is improved by detecting changes in amplitude and/or frequency of noise output. The sensor can also be used to detect a level of oil for instance in an engine oil pan.

Abstract: Method and apparatus for determining deterioration of e.g. lubricating oil by measuring the contraction of a polymeric matrix (support) holding charged ionic groups. The support contracts due to oil quality degradation. The expansion/contraction is detected e.g. electrically.

Abstract: A detection system measures very small concentrations of compounds of interest within gaseous samples. A spark discharge system induces pulsed spark discharges across a pair of electrodes within an inert gas in a gas flow chamber. Various reactions are induced by spark interaction with the flow of inert gas, and with any sample or dopant commingled with the inert gas, in the region of the pulsed spark discharge. This induces photon ionization which creates an instantaneous current flow within the gas flow chamber. Current flow is held constant for all concentrations of sample introduced into the gas flow by means of a control feedback system. The output of the control feedback system is indicative of sample concentration. The system responds linearly over approximately five orders of magnitude of sample concentration for use with the sample which will be described and low femtogram sensitivity is achieved.

Abstract: A conductivity measuring device has a current source device connected to current supply elements through which a substantially square-wave current can be fed into a liquid, and a measuring circuit for determining the voltage drop in the liquid between voltage measuring elements.

Abstract: A device or system for monitoring for the presence of leaks from a hazardous fluid is disclosed which uses two electrodes immersed in deionized water. A gas is passed through an enclosed space in which a hazardous fluid is contained. Any fumes, vapors, etc. escaping from the containment of the hazardous fluid in the enclosed space are entrained in the gas passing through the enclosed space and transported to a closed vessel containing deionized water and two electrodes partially immersed in the deionized water. The electrodes are connected in series with a power source and a signal, whereby when a sufficient number of ions enter the water from the gas being bubbled through it (indicative of a leak), the water will begin to conduct, thereby allowing current to flow through the water from one electrode to the other electrode to complete the circuit and activate the signal.

Abstract: A surface-mounted pH sensor provides continuous pH profiling with depth during standard cone penetration testing (CPT). The pH sensor includes at least two electrodes, one being an antimony electrode and the other being a ceramic electrode. The electrodes are mounted to the shaft of a cone penetration device, and make contact with underground fluids during CPT. The antimony electrode, which functions as a measurement electrode, creates an exchange equilibrium between the hydrogen ions in the underground fluids and the ions of the antimony. This equilibrium creates a potential in the antimony electrode which is measured against the stable reference potential of the ceramic electrode. The resulting potential difference is indicative of the pH level of the underground fluids.

Abstract: An apparatus and method for measuring electrical parameters of a medium such as electrical conductivity and dielectric constant between a pair of electrodes are disclosed. The medium can be a liquid, gas, powder, etc., and the electrodes can be coaxial metallic circular cylinders. To compute electrical conductivity, the device is immersed in the medium to an immersion depth and the conductance across the electrodes is determined. The measurement is repeated at at least one additional immersion depth. By obtaining a differential conductance measurement with respect to the immersion depth, the effects of fringe conductances are eliminated from the measurement. The device can also be used to determine dielectric constant of the material by obtaining a differential capacitance measurement with respect to immersion depth. The device need not be calibrated by performing resistance measurements in a known standard solution.

Abstract: An electrochemical test cell for measuring conductivity and transport properties of a solid or liquid electrolyte comprises a longitudinal chamber, produced, e.g., from a syringe, a pair of electrodes and means for holding the electrodes which defines an adjustable volume for containing the electrolyte and which aids in maintaining contact between the electrolyte and the electrode.

Abstract: A method and apparatus for determining the quality of a lubricant by its solvating effect on an insoluble (resin) matrix to which charged groups have been covalently bound. The solvating effects are measured electronically as a variation in conductivity or capacitance of the resin matrix with respect to temperature. The apparatus includes a metal mesh housing containing e.g. milligram amounts of charged resin beads. A metal probe is fitted in the containing mesh and makes contact only with the resin beads. The entire device is immersed in the lubricant and the electrical conductivity or capacitance is measured from the probe to the mesh through the resin beads. Lubricant degradation is measured as e.g. a decrease in electrical conductivity through the resin beads with respect to an increase in the lubricant's solvent polarity.

Abstract: A fuel sensor for sensing methanol in methanol-mixed fuel, which comprises a structure which defines a fuel passage through which the mixed fuel flows, an electrode assembly including a pair of probe portions which are exposed to the fuel passage, and an electric circuit causing the paired probe portions to exhibit positive and negative characteristics respectively in the mixed fuel. At least the positive probe portion is intimately covered with an electrically insulating film.

Abstract: A spark detection apparatus is set forth and incorporates a closed chamber for receiving a carrier gas flowing therethrough between inlets and outlets, and the carrier gas is exposed to a pair of electrodes forming a spark across the chamber and through the carrier gas. Compounds of interest interact with the spark. The spark forms a diffusion of electrons or alternately ions during the spark distributed thereafter. The chamber includes a detector electrode spaced from the spark. High mobility particles (primarily electrons) are observed almost instantaneously with the spark while low mobility ionic particles diffuse more slowly after the termination of the spark. Using an inert carrier gas, high energy metastable molecules are dispersed and give up energy over time after the spark. The output is obtained from the electrode during, immediately after, or after a long delay relative to the spark. Another alternate output is obtained from the observed spectra during the spark and after the spark.

Abstract: A conductivity meter usable in solutions where the path of the electric lines of force between two electrodes is altered. In one embodiment, detachable guard rings alter the path length based upon their own conductivity. In another embodiment, the physical distance between the electrodes is altered while maintaining a constant electrode configuration.

Abstract: A low pressure ion-chromatograph for the analysis of cations comprises eluent reservoirs, pump, sample injection valve, sampler, column, flow conductivity cell, electrical conductivity detector and recorder, wherein the pump is a low pressure electronic micropump, the angle included between the inlet and outlet of eluent in the cell is 45.degree.-135.degree., and the flow conductivity cell is oriented in such a position that the eluent inlet is either horizontal or sloping upwardly. There is no leakage in this instrument. No special demands are needed for seal and material. Very good precision and high sensitivity up to ppb level can be obtained, and with low cost.

Abstract: A method and apparatus for measuring the electrical conductivity of a liquid comprises an electrically insulating housing through which the liquid flows, and four electrodes inserted into the path of the liquid flowing through the housing. The first and third electrodes are current electrodes and the second and fourth electrodes are voltage electrodes. An AC current is injected into the first current electrode and exits at the second current electrode, with the resulting AC voltage across the voltage electrodes being measured. The first current electrode is driven to maintain a constant value of AC voltage on the voltage electrodes while measuring the current flow in the second current electrode which is representative of the electrical conductivity of the liquid. A DC bias voltage source is provided and is coupled to each of the electrodes by a resistor and a capacitor to prevent coating or plating of the electrodes.

Abstract: A conductivity probe able to withstand high water temperatures and pressures, and intense nuclear radiation is suitable for use within the core of the nuclear reactor. The probe is made with a ceramic insulator, such as sapphire, and a central electrode that is mounted on the insulator. A sleeve that supports the insulator and the central electrode is made from metals having a coefficient of thermal expansion compatible with the coefficient of thermal expansion of the insulator, such as Kovar. The central electrode and sleeve are bonded to the insulator by a brazed compressive seal that protects an internal conductor in the probe from intrusion of the reactor water. A counter electrode made from a corrosion resistant metal, such as Kovar, is attached to the sleeve so that it extends over the central electrode a fixed, spaced distance. A positioning and signal transfer arrangement operatively supports the sleeve and conveys electrical signals to and from the two electrodes.