Abstract: In a streaming current detector, a standard calibration solution is used to calibrate the streaming current signal representing the charged condition in a sample fluid containing particles. The standard calibration solution is electrokinetically stable over a wide range of pH and concentration. Calibration allows direct comparison of readings from different streaming current detectors.

Abstract: A device for measuring ionic concentration in a sample liquid, having a detachable waterproof electrode housing. A body member has a computing device disposed therein and a display panel on an exterior surface. The waterproof electrode housing is demountably coupled to the body member. The electrode housing includes a flat surface sensor capable of measuring ionic concentration of the sample liquid when the device is placed on a flat surface, and is waterproof for measuring ionic concentration by immersion. A gap is formed between the body and the flat surface for preventing water from entering the body when the flat surface ionic concentration measurement procedure is being conducted.

Abstract: An electrolytic conductivity detector cell featuring a flow bore for communicating gaseous products of a gas chromatographic system designed to provide electrolytic conductivity supporting compounds, combined with a liquid solvent in which the compounds in question dissolve. Electrodes are provided, in general, in the form of conducting pins which are positioned in bores in the cell block, intersecting the flow bore to expose surfaces of the electrodes to the fluids in the bore.

Abstract: A sensor cable for detecting the presence of electrically conductive liquids, e.g. water. The cable has decreased sensitivity to contamination and condensation than conventional cables which are covered by braids. First and second elongate conductors are positioned in first and second channels which partially surround the conductor and are part of first and second insulating support members; each channel has at least one shoulder which extends outwardly from the channel beyond the conductor. The channels are positioned so that when the cable is placed on a flat substrate in any position, neither the first nor the second conductor contacts the flat surface and at least one first shoulder and at least one second shoulder make intermittent contact with the flat surface. In a preferred embodiment, the first and second conductors follow a generally spiral path down the length of the cable.

Abstract: A particle detector is designed to detect particles such as cells and blood corpuscles, and this particle detector includes means for passing and recovering a multilayer flow consisting of an inner layer A of conductive liquid specimen, a middle layer B of conductive first sheath liquid, and an outer layer C of nonconductive second sheath liquid surrounding them, in an orifice 12, and a pair of electrodes disposed on both sides of the orifice so as to contact the conductive liquid respectively. A detector circuit 44 is connected to the pair of electrodes so as to detect a particle signal on the basis of difference of electric impedance between the electrodes. The diameter of the orifice 12 is substantially the diameter of the middle layer. By varying the flow rate balance of the conductive liquids and nonconductive liquid, the diameter of the middle layer may be freely changed. Accordingly, the diameter of the orifice may be apparently changed as desired.

Abstract: A water quality monitor is provided for use in a purified water supply system of the type having a reverse osmosis unit for producing relatively purified water from an ordinary tap water supply. The monitor includes a control circuit having electrodes in contact with the purified and tap water supplies. The control circuit is activated by depression of a test button, preferably in response to opening of a faucet valve to dispense water, to produce a short duration pulse of one polarity which is connected to the electrodes for use in determining the water conductivities. The control circuit compares the conductivities of the purified and tap water supplies, and maintains an appropriate indicator light in an illuminated state until the test button is released, at which time the control circuit couples a short duration pulse of opposite polarity to the electrodes for minimizing electrode corrosion and/or accumulation of ionic deposits.

Abstract: An apparatus for measuring cathodic protection voltage levels on a concealed conductive structure, includes a probe having a standard half cell reference electrode, a working electrode and an auxiliary electrode mounted in a fixed spacial relationship to each other, wherein the reference electrode, working electrode and auxiliary electrode are each in contact with an electrolytic solution. A voltage measuring device is provided for receiving a voltage from said reference electrode. The voltage measuring device provides an indication of the voltage difference between the reference electrode and a common reference point. A switch is included for connecting and disconnecting the working electrode with the common reference point. A voltage detecting circuit detects voltage between the concealed conductive structure, which is subject to a cathodic protection voltage, and the common reference point.

Abstract: A device is provided for improving the measuring accuracy of a process for determining the alcohol content and/or the calorific value of fuels by measuring the electrically measurable qualities of fuel. At least one component of the fuel system of an engine is used with a counterelectrode for the capacitive dielectric measurement of the fuel. At the same time, it is suitable to also use a component of the fuel system with respect to a counterelectrode for the measurement of the conductivity of the fuel. The same counterelectrode can be used for the dielectric measurement and for the measurement of conductivity of the fuel.

Abstract: A device for detecting relative differences in conductivity between filtered and unfiltered states of fluid comprises a differential comparator for measuring the voltage difference of its input ports, a differential bridge connected to the input sorts of the differential comparator for measuring the conductivity of the fluid, the differential bridge having electrodes for contacting the fluid in each of its filtered and unfiltered states and bridge adjustment circuitry for compensating for voltage offsets of the comparator and the bridge, and an indicator connected to the output of the comparator for generating an output indicative of the differential conductivity of the fluid in its filtered and unfiltered states.

Abstract: An arrangement of probes is described, which comprises a carrier formed as an intermediate flange, in which a plurality of radially extending mounting openings are provided. The inner surfaces of the carrier are provided with an electrically insulating corrosion resistant layer, which is preferably an enamel layer. The carrier is having a polygonal outline and plane mounting surfaces surrounding the mounting openings. Measuring probes provided with a mounting flange can be exchangeably and sealingly attached to the mounting surfaces. By arranging different probes a large number of different measurement functions and supervision functions can be achieved. As an example, carrier sleeves comprising a window can be built in, so that a visual observation or a turbidity measurement can be performed.

Abstract: A water quality monitor is provided for use in a purified water supply system of the type having a reverse osmosis unit or the like for producing relatively purified water from an ordinary tap or feed water supply. The monitor includes a control circuit having eletrodes in contact with the purified and tap water supplies. The control circuit is activated by depression of a test button to produce a short duration pulse of one polarity which is connected to the electrodes for use in determining the water conductivities. The control circuit compares the conductivities of the purified and tap water supplies, wherein this comparison represents the operational efficiency of the purification system in removing contaminants from the incoming tap water. The control circuit responds to this comparison to illuminate an appropriate indicator light or the like and thereby indicate the operational state of the purification system.

Abstract: Apparatus for indicating a predisposition to kidney stone disease in humans, and also dehydration, and for monitoring the efficacy of hydration therapy, comprises a conductivity probe including a tip which can be inserted into urine so that a drop thereof adheres to the tip, and display means for indicating the result as a derived function of conductivity (electrolyte concentration) in terms of urine specific gravity or osmolality. Preferably the probe electrodes are small and are spaced closely together so that the streamlines between the electrode tips are such that maximum current flows substantially within the adherent drop of urine.

Abstract: Two lead wires for each, connected to opposite ends of a heat generating element are secured to a holder. These lead wires form four-point-terminals at their other ends and thereby a disposable sensor is provided. A current source and a voltmeter are connected to the terminal and changes in various properties of fluid are determined on the basis of a value of current supplied from the current source and a value of voltage measured by the voltmeter.

Abstract: An amperometric method for the direct measurement of acidity in a medium which contains at least one ester of an acid containing oxygen, and whose dielectric constant is lower than 30. The method provides for maintaining a constant voltage between an ultramicroelectrode and a counterelectrode and measuring the current therebetween as an increasing quantity of diphenylphosphoric acid is added to the medium via a microburette. The measured current being indicative of the acidity of the medium under test. A predetermined curve is provided which represents the relationship between the acidity of the medium and the current measured by the system.

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 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.

Abstract: Disclosed is an electrode probe for employment in monitoring electrochemical potentials and which has a robust structure particularly suiting it for employment within the rigorous environment of the reactor core of a nuclear power facility. The electrode of the present invention is comprised of four major segments: a metal cap electrode, an alumina retainer, an annular metal sleeve, and a positioning and signal transfer assembly. The metal cap electrode has a tip portion and an annulus extending therefrom which defines a cavity having an interior surface. The alumina retainer has a base region with a sleeve attachment surface, an oppositely disposed cap securing portion nestably disposed within said cap electrode cavity and sealingly attached thereto. The retainer further has an axis channel penetrating therethrough from the base region to the cap securing portion.

Abstract: A sensor for electrochemical measurement is disclosed which includes a chamber made of an electrically insulative material and having an open end portion, a super absorbent polymer material filled in the chamber and absorbing at a selected rate a liquid electrolyte, an electrode disposed in the chamber, and a screen which covers the open end portion of the chamber and which prevents the super absorbent polymer material from dropping out from the chamber but permits the liquid electrolyte to transmit through the screen. A method is also disclosed which uses the sensor to measure the degree of degradation of a coating film on metal or the corrosion protective properties of a rust film created on the surface of steel.

Abstract: An apparatus for measuring the electrical charge condition of non-conductive particles in a liquid medium comprising a flow path having sensory means for developing a signal proportional to a desired ion activity and a reciprocating piston carrying a grounded electrode. The reciprocating piston induces liquid to flow past the sensory means and the electrode on the piston screens external galvanic interferences and lower electrode impedance. The electrical signals are monitored by an electronic component.

Abstract: A salt sensor is disclosed which is portable and easily handled by a person at a restaurant or in his home for determining the sodium content of the food or beverage he is about to consume. The salt sensor includes a uniquely designed contact top which is electronically connected to a circuit which generates an AC signal. The strength of the signal transmitted across the contact tips is directly proportional to the conductivity of the food or beverage being tested and is, accordingly, registered on a display panel located on the body of the salt sensor.

Abstract: A circuit is utilized for measuring a diffusion-limited current which flows through a diffusion-limited current element in proportion to an oxygen concentration which includes an output resistor connected in series with the element, a differential amplifier having a first input connected to a reference voltage supply source, a second input connected to ground, an output connected to the output resistor, and a feedback resistor connected between the first input of the differential amplifier and a point between the element and the output resistor, so that a bias voltage applied across the element is kept constant.

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 particle detector in which a pair of pipe elements are coupled together through an aperture and the liquid to be tested is passed through the pipe elements and the aperture with a voltage or current applied to the liquid through the pipe elements acting as electrodes so that the diameter of the pipe elements is reduced because the electrodes are not provided in the pipe elements.

Abstract: The invention relates to a device for measuring the impedance of a medium along a measurement line, the medium being either sea water or a sediment on the sea-bottom or else a mixture thereof. According to the invention, a special antenna (2) is used, which extends along the measurement line and contains a succession of ring electrodes (10, 11), which can selectively be fitted into a meter circuit (FIG. 2) via cyclically switched Reed relays (34, 35). The invention can especially be applied to the study of the alterations of a hole in a sediment at sea-bottom created behind a torpedo-shaped container penetrating by gravity into the sediment.

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 three wire amplifier circuit for use with a sensor in which the amplifier output drives the negative supply so that the negative supply becomes the circuit output and the system is capable of diagnosing the condition of the sensor.

Abstract: A liquid conductivity sensor which features simply and inexpensively driving the excitation transformer of a two-transformer/fluid-loop remote conductivity sensor with a square wave excitation signal provided by a digital timer and a flip-flop. Also disclosed is using an electrodeless conductivity sensor to sense conductivity of dialysate.

Abstract: A highly reliable bilge pump control system which distinguishes between oil and water and operates without a mechanical float switch. It uses a conductivity type probe of special construction which is unaffected by sludge and contamination at the oil-water interface. Multiple probes at varying depths feed high impedance operational amplifiers which operate a conventional pump through digital circuitry which assures that no oil is pumped from the bilge.

Abstract: An enamelled or glass coated measuring probe is described, comprising a carrier an electrode fused into an enamelled probe body. The carrier is shaped as a cone out of enamel or ceramic material, into which the electrode or cylindrical metallic body serving for mounting the electrode is fused. In accordance with one embodiment one or several electrodes can be fused into the cone, while in another embodiment the electrode may be exchanged by an electrode out of a different material.

Abstract: A liquid level gauge consists of two main cells comprising a measuring electrode, a compensation electrode and their respective counter electrodes. Circuitry is provided to determine the conductance of the liquid in each cell. Further circuitry is provided to calculate the quotient of the respective cell conductances, which is indicative of the liquid level. The surface areas of the measuring and compensating electrodes are kept equal, but the distance between the measuring electrode and its counter electrode increases linearly, while the distance between the compensation electrode and its counter electrode is constant.

Abstract: Sensor assembly and system for sensing conductivity and thereby controlling the concentration and level of a solution includes first and second probes adapted to be at least partially immersed in the solution whose conductivity is to be sensed. The probes are fixedly supported in a predetermined geometrical relationship with respect to each other in an externally mounted housing. Each of the first and second probes has an outer insulative sheath and an inner conductive electrode, the electrodes being exposed to the solution at least one point when their probes are immersed therein. At least one of the electrodes is recessed a predetermined distance from an open end of its respective sheath so that the solution must fill a predetermined volume in the sheath corresponding to the predetermined distance before contacting the electrode. The probe including that one of the electrodes has a clear path therethrough to permit solution to rise therein to a level of the electrode.

Abstract: A probe that is used to determine the etch rate of a nonconductive material is comprised of a substrate of the material itself, plated on opposite sides with a conductive material. A first side of the probe has a small area of the plating removed to expose the substrate. The other side has an annular portion of the plating removed to define a wafer of plating isolated from the remainder of the plating. A lead wire is connected to the wafer and the entire second side of the probe is coated with an insulating mask. The probe is immersed in a bath of the etching solution. A voltage source is connected to the probe and to an electrode also immersed in the bath. A measurement device is connected in the circuit to detect current flow. When the etching bath dissolves the substrate through the exposed portion, a circuit is completed with the lead wire and the current flow is detected. The time from immersion of the probe to the beginning of current flow is used to calculate etch rate.

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 disposable low cost electrode structure for measuring platelet aggregation in whole blood or PRP which utilizes conductive ink or foil for the electrodes with the electrode pattern printed, heat-stamped or silk-screened onto a suitable plastic non-reactive base. The base material can be any material which does not react with blood and is stiff enough, for example a polycarbonate, while the conductive element can be made with a silver conductive ink. The electrodes can be on one or both sides of the base or substrate material. Platelet aggregates start and build up on the leading edge of a narrow body inserted into the flow path of the blood. The conductive pattern must have its active element on or very near the leading edge of the electrode base material, and in contact with the blood, and the non-active areas of the conductive pattern must be insulated electrically from the blood or plasma being tested so as to allow sensing of the change in resistance caused by the platelet build-up on the active area.

Abstract: A low pressure steam turbine which is subject to an extremely narrow corrosive salt deposition zone includes rotating and stationary blades. One of the stationary blades has an array of sensors thereon divided up into a plurality of rows, one near the tip of the blade, one near the root of the blade and the third intermediate the two. The sensors are of the type which are flexible so as to conform to the curvature of the blade and will provide an output signal indicative of the presence of a salt solution. The outputs from the sensors are analyzed to provide an indication of the location of the salt solution zone.

Abstract: A retaining clamp for use with a combination valve and conductivity cell assembly is formed from two identical clamp halves which, when closed upon the valve and conductivity cell assembly, tightly connects the valve nipple and operating safety nut of the assembly in fixed operating relationship to insure proper reciprocal movement of the valve sleeve.

Abstract: A paraffin monitor apparatus responsive to changes in resistance includes a plurality of paraffin sensing means which are placed in a liquid medium containing paraffin. The paraffin sensing means are housed in a non-metallic, hard material having a plurality of channels so that each paraffin sensing means has at least one surface substantially in conformity to a surface of the non-metallic, hard material. A predetermined length of tubing is affixed to the non-metallic, hard material, and a plurality of wires, each of which passes through a channel of the non-metallic, hard material and the tubing, connect with corresponding paraffin sensing means. An adapter affixed to the tubing permits insertion of the non-metallic, hard material and a portion of the tubing into a pipeline containing a flowing liquid medium having paraffin.

Abstract: A system for measuring the flow rate of electrolytic fluids includes a flow cell which has a cylindrical flow channel receptive of the fluid flow to be measured and a pair of spaced apart electrodes configured to conform to the cylindrical surface of the flow channel and to be flushed therewith. The electrodes are electrically conductive and inert to the fluid of the flow and a channel is configured to effect contact of the electrodes with the fluid flow for a desired range of flow measurement. A monopolar pulse train is applied across the electrodes to effect a cell impedance across the electrodes which is inversely proportional to the rate of flow.

Abstract: A sensor for a hydro resistance anemometer is designed for immersion in a flowing fluid to provide flow velocity information. The sensor is of a cylindrical configuration with a hemispherical nose. A driving electrode extends axially along the sensor and is exposed to the flowing fluid only at the center of the hemispherical surface of the sensor nose. A reference electrode of annular cylindrical configuration is disposed coaxially about the driving electrode and separated therefrom by a dielectric insulating material. The power dissipated through the sensor is typically on the order of only ten milliwatts.

Abstract: A conductivity sensor for placement on a curved steam turbine component within the steam path. The sensor includes a metal foil base over which is deposited an electrically insulating layer such as glass. The base and insulating layers are of such thickness so as to be flexible so as to conform to the curved surface. An electrode array is deposited upon the insulating layer and spaced so as to accommodate for deposition of steam impurities onto the insulating layer. Flexible links connect the electrodes to electrical leads so that conductivity indications may be obtained.

Abstract: A molded one-piece housing for use in fabricating conductivity cells. An electrically nonconducting housing includes an internal partition which divides the interior of the housing into a first region for receiving a test liquid and a second region for receiving a plurality of electrical conductors. Openings through the partition provide passages through which measuring electrodes may project into the first region to establish cell constants of the desired magnitude. These openings are so shaped that they establish a liquid-tight seal between the housing and the electrodes during insertion. By means of this seal the electrodes are held firmly in place during the assembly of the cell. This seal also permits a potting compound to be introduced into the second region without leaking onto and thereby affecting the electrical characteristics of the electrodes.

Abstract: Analytical apparatus is arranged for increased sensitivity in determining a desired characteristic by decreasing the sensitivity to extraneous noise, essentially as common mode signal, while treating the desired signal differentially. Test signal is applied to apparatus comprising an electrochemical cell containing electrolyte in which a pair of matched working electrodes are equispaced from a counter electrode and from a reference electrode. The working electrodes conduct different values of current, the difference being a measure of characteristic of material making up the electrolyte. The signal applied between the counter and the working electrodes is varied over a predetermined range. The potential between the working electrodes is established at zero for basic operation, but a fixed biasing potential is established between the two working electrodes for a given experiment in which the test signal is varied.

Abstract: In electrophotography or electroradiography charge images are formed which are customarily made visible by means of toners. The invention provides an electrostatic probe device for the electric scanning of charge images. The device, therefore, is particularly suitable for use in conjunction with digital image processing and storage. The device in accordance with the invention comprises a large number of electrode tracks which are provided on a flat substrate and on which there is provided an insulating layer on which a conductive layer is provided. The latter layer comprises cut-outs at the area of the electrostatic probe electrode heads. This device is suitable for the simultaneous measurement of the charge distribution at some hundreds of measuring locations.

Abstract: A compact, battery-powered water resistivity sensor measures the resistivity of water, sequentially compares the measured resistivity to a plurality of predetermined resistivities, and numerically displays that one of the plurality of predetermined resistivities approximating the measured resistivity. Preferably, the pair of electrodes consists of a pair of printed circuit electrodes disposed conveniently on the end face of an insulating nut extending, in fluid-tight fashion, into the tank of water. The sensor is powered by a battery, and includes circuitry for interrupting the supply of battery power to various circuit elements, the functions of which elements are no longer needed once the water resistivity is determined by the sensor. The sensor also includes temperature-sensitive compensation means responsive to changes in the water temperature for varying an input signal provided to the electrodes.

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 sensor for use in a steam turbine in operation to monitor corrodents being deposited therein. The sensor comprises a bottom substrate on which an electrode pair is located. The bottom substrate also includes a means for measuring the temperature at the bottom substrate. A first layer of dielectric material is bonded to the top of the bottom substrate. The first layer has an aperture formed therein so that an end of the electrode pair is located in the aperture. A second layer of dielectric material is bonded to the top of the first layer. The second layer defines a crevice for entrapping steam-transported corrodents that are deposited in the turbine. A portion of the bottom of the crevice includes the aperture so that corrodents are also deposited in the aperture. By passing a current between the ends of the electrodes located in the aperture, a measure of the conductivity and thus the concentration of corrodents deposited in the aperture and crevice is given.

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 disposable sample for use in measuring a parameter of a liquid sample such as the hematocrit and a method of making same. The disposable sample card is a micro-volume conductivity cell precision molded from plastic with built-in stainless steel electrodes. The sample card comprises a planar base portion on which is defined a capillary tube. First and second electrodes are disposed within the capillary tube in a spaced relationship and define a volume within the capillary tube. This volume constitutes a conductivity cell. The sample card may be used with an instrument which basically comprises an electronic portion for processing data obtained from the liquid sample on the sample card, a front-end mechanism for positioning the sample card within the instrument, and a digital display for displaying in eye-readable form the results of a parameter measurement made in the instrument.

Abstract: The local void fraction in liquid containing a gas is measured by placing an impedance-variation probe in the liquid, applying a controlled voltage or current to the probe, and measuring the probe current or voltage. A circuit for applying the one electrical parameter and measuring the other includes a feedback amplifier that minimizes the effect of probe capacitance and a digitizer to provide a clean signal. Time integration of the signal provides a measure of the void fraction, and an oscilloscope display also shows bubble size and distribution.

Abstract: A method of and an apparatus for determining the dielectric breakdown chateristics and size of membrane-sheathed particles such as living-organism cells and the apparent size of such particles after breakdown of the membrane, makes use of two measuring orifices traversed by an electrolyte across which an increasing electric field is applied during the measuring process in which the particles successively traverse one of the orifices. The current through the measuring orifice deviates from the linear with increasing field generated preferably by a sawtooth voltage, the current change being used to measure the particle variables stated.