Abstract: A differential DC/RF bridge-configured flowcell particle detector includes a flowcell and an adjustable circuit model of the flowcell, which are differentially coupled through output amplifier circuits and galvanically isolated from sources of signal degradation. The output of the difference amplifier is coupled to a DC/RF discriminator and associated downstream processing circuitry. Respective amplitude and phase outputs of the DC/RF discriminator are used to control amplitude and phase adjustment circuits of the adjustable circuit model, so as to automatically track amplitude and phase variations in the non-linear behavior of the flowcell, to mirror the characteristic impedance of the flowcell, thereby making the bridge insensitive to variations in the flowcell.

Abstract: A streaming current sensor on which the placement of the sample outlet lower on the vertical axis than the sample inlet so as to increase the accuracy, reliability, and sensitivity of the sensor in comparison to those of the prior art, by enabling contaminants within the sample fluid to be removed from the buffer space before coming into contact with the sensing electrodes. The sensor further has a buffer space enabling the fluid to become a homogenous mixture of sample fluids before contacting the electrodes, thus increasing signal stability.

Abstract: A system for monitoring debris in a fluid by detecting electrostatic charges associated with the fluid. Both the electrostatic characteristic of the fluid and of the debris are sensed and then separated by a processor that compares their mobility. The monitoring system may be used to detect debris in any fluid capable of being electrostatically charged, such as oil and superheated steam.

Abstract: A materials characterization test cell is disclosed. The test cell includes a housing including spacers for supporting sample insulation materials, and a channel disposed in the housing to permit the passage of oil through the housing. A pair of electrodes is provided to provide a mechanism for making polarization spectrum and/or streaming electrification measurements.

Abstract: A sensor installable within a gas turbine engine for sensing electrostatic charge therein. The sensor comprises a sensing plate and first and second shielding plates. The sensing plate has a first face with a first peripheral portion, and a second face with a second peripheral portion. The first and second shielding plates are spaced from and positioned relative to the first and second faces of the sensing plate, respectively, by a layer of electrically insulating material, so that electrostatic charge in the proximity of the sensor is sensed by both the first and second peripheral portions of the sensing plate.

Abstract: A method and device is disclosed for determining the distribution of charge and size in a colloidal system. The arrangement disclosed is adapted to measure these characteristics in an inhomogeneous colloid. A colloid is subjected to a steady or slowly varying force which moves the particles at a rate that depends on their radius or charge and thereby sets up spatial inhomogeneities in the suspension, and to either a unsteady mechanical force or an unsteady electrical force, and the resulting electrical or acoustic effects sensed. Monitoring these characteristics over time and subsequent calculation allows the determination of charge and size distribution, for each species present.

Abstract: A system and method for coincidence detection of ungrounded or inadequately grounded parts during the electrostatic coating process in order to improve production flow, provide an overall cost saving by efficient use of the coating material and prevention of accidental fires and false shutdown during production. The present invention utilizes a coincidence detection technique which performs a test for radio-frequency electromagnetic energy radiated by sparking and/or corona discharge caused by ungrounded parts outside a electrostatic coating area and a test for sensing and discriminating spurious radio-frequency electromagnetic energy radiated by sparking and/or corona discharge caused by any other external source. In accordance with one specific embodiment, the test performed outside the booth may include a further test for detecting ultraviolet energy radiated by the sparking and/or corona discharge.

Abstract: Solid state gas sensors are provided, the use of which permits quantitative measurement of gaseous contaminants or change of composition of a gas or atmosphere being monitored. The gas sensor comprises at least a base, a first electrode, a second electrode. The first electrode has a finely tapered end to strengthen the electric field intensity in the gap between the first and the second electrodes. The sensing is based on ionization potential difference between the molecules of the contaminating gas and of the atmosphere. When a high voltage is applied to the electrodes, it creates a strong electric field between the electrodes, especially a very strong electric field around the tapered end of the first electrode. When the potential is sufficiently high, the gas in the vicinity of the tapered end of the first electrode will be ionized. The ions and electrons generated by the ionization create an electric current flows between the two electrodes and across the gap.

Abstract: A metallic indicator electrode senses the anionic charge per unit time borne by the dispersed phase of a stream of an aqueous dispersion of negatively charged particles by virtue of the potential developed by the electrode as measured by a voltmeter. The developed potential can be used downstream, for example, to control the addition of a water treatment chemical or extraction of water from the stream.

Abstract: The invention is an electrostatic coalescer testing apparatus for testing the ability of chemical additives to facilitate electrostatic coalescence of water in a water hydrocarbon-containing mixture.

Abstract: An apparatus for automated polyelectrolyte measurement in process materials comprises a sample vessel with an outer wall defining a cylindrical cavity and with a reservoir of larger diameter above and in communication with the cavity. A liner for the cavity and the reservoir are made of an electrically insulating material such as polytetrafluoroethylene. To clean the apparatus there is also provided an ultrasonic oscillator which is mechanically coupled to the sample vessel. In order to improve the cleaning process, the liner and preferably also the reservoir are attached to the outer wall in such a way as to resist tensile and shear forces and the ultrasonic oscillator is attached to the outer wall. Preferably, the liner is attached to the outer wall by an adhesive.

Abstract: A contactless method and apparatus for in-situ chemical etch monitoring of an etching process during etching of a workpiece with a wet chemical etchant are disclosed. The method comprises steps of providing at least two toroidal windings in the wet chemical etchant to be proximate to but not in contact with the workpiece; and monitoring an electrical characteristic between said at least two toroidal windings, wherein a prescribed change in the electrical characteristic is indicative of a prescribed condition of the etching process. Such a method and apparatus are particularly useful in a wet chemical etch station.

Abstract: A contamination monitoring system for monitoring contaminants in a liquid, comprising a first electrical conductivity sensor, a second electrical conductivity sensor, a filter and a pump, the filter being disposed between the first sensor and the second sensor, the pump being arranged to circulate the liquid, the first electrical conductivity sensor providing an indication of dissolved ionic contamination levels in the liquid prior to filtration of the liquid by the filter, the second electrical conductivity sensor providing an indication of dissolved ionic contamination levels in the liquid after filtering the liquid by the filter, the conductivity measured by the second electrical conductivity sensor being compared against a value to determine whether the liquid should be retained or discarded.

Abstract: Apparatus for automated polyelectrolyte measurement of liquid process materials including a sample vessel which defines an electrically insulating, cylindrical cavity below a larger-diameter reservoir. Electrodes are located at the ends of the cylindrical cavity and an insulating piston is reciprocated with a predetermined, small clearance within the cavity. The charge displacement is measured between the electrodes. An outlet channel opening at the floor of the cylindrical cavity is connected to an outlet pipe. A rinsing duct with valve control for introducing a rinsing fluid into the reservoir. A controller is connected to an actuator for reciprocating the piston, to a valve in the outlet pipe and to the rinsing valve. After each polyelectrolyte measurement the substance under test is removed from the sample vessel through the outlet channel, rinsing fluid is introduced, and the rinsing fluid is removed through the outlet channel while the piston reciprocates.

Abstract: An apparatus for measuring the conductivity of a fluid is disclosed. The invention 10 provides both a contact and non-contact monitoring of fluid conductivity by measuring the A.C. dielectric properties of the fluid. The invention 10 transmits an electromagnetic wave into the fluid 22 and analyzes the transmitted and reflected waves providing an indication of the conductivity of the fluid 22. The invention 10 is versatile in that it allows for the fluid to be in the form of a spray. In a specific illustrative implementation, a novel nozzle is provided to monitor the conductivity of paint spray 22 as it passes therethrough.

Abstract: An apparatus for detecting an electrostatic force in a solution includes a sample and a cantilever. An end of the cantilever is conductive and has voltage applied to it. The apparatus detects electrostatic interaction caused by functional groups of target molecules in the solution.

Abstract: The invention describes a novel device to measure .zeta.-potentials of substances at high temperatures. The device involves packing the substance to be measured into a "RULON" (polytetrafluoroethylene including a heat resistant filler, e.g., fiberglass, quartz, asbestos, ceramic fibers or mica) column and passing an electrolyte through the column. Measurements are taken across the column to measure streaming potential and the pressure drop, and a sensor in series with the column to measure the pH of the electrolyte. .zeta.-potentials are calculated from slopes of the plots of streaming potential (.DELTA.E) vs. differential pressure (.DELTA.P) using a computer controlled data acquisition system.

Abstract: A system is disclosed for controlling the amount of treatment composition, e.g., cationic coagulant, to be introduced into an aqueous medium, e.g., a laundry waste water, having a content of non-solid fats, oils and/or grease (FOG) which is to be reduced. This system comprises a detector adapted to determine the electric charge value of a material comprising the aqueous medium having a FOG which is to be reduced and to provide a signal indicative of this electric charge value and an automatic processor provided with a relationship of the amount of treatment composition to be introduced into the aqueous medium to reduce the FOG of the aqueous medium to a given level as a function of the signal, and adapted to receive the signal and to provide a control signal to a source of treatment composition to control the amount of treatment composition introduced from the source of treatment composition into the aqueous medium.

Abstract: An apparatus for determining the particle charge and size distribution of particles in suspensions of arbitrary concentration is provided. The apparatus includes a cell for application of an unsteady electric field or an unsteady mechanical force across the suspension of at least two different frequencies for accelerating the particles. The resulting acoustic wave generated by application of the electric field applied to the electrodes, or the electrical response and the acoustic pressure at the electrodes generated by application of the mechanical force is measured. Transducers convert the mechanical forces to electrical forces.

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 detecting and monitoring the charge condition of finely divided solid charged particles in a fluid-flow is so devised as to accept the continuous and full volumetric flow of the fluid and to automatically and repeatedly sample and measure the charge condition. The full flow is accommodated without restriction in a passageway which intersects a bore wherein a streaming current detector (SCD), located below the passageway, is caused to cyclically sample and measure the charged-particle content of the flow; and at a passageway location downstream from the point point of cyclical sampling a head-creating formation assures that the fluid level will be raised to maintain a filled condition of the sampling bore. The device is further illustratively disclosed in use in a fluid-treatment system, wherein the SCD produces a signal to control flocculant added to the full flow of the fluid.

Abstract: A method of making a calibrated measurement of the contact potential difference between a probe electrode and the surface of a sample surface involves the use of a reference standard. The reference standard comprises an electrolyte solution in electrical contact with an electrochemical half-cell; the surface of the electrolyte constitutes the reference surface whose CPD can be measured. The method is intended for use with apparatuses such as a vibrating capacitor or Kelvin probe, and allows the absolute work function of a sample surface to be determined from measurements obtained in a gas atmosphere. An apparatus incorporating the reference standard, and an improved vibrating capacitor probe, are also disclosed.

Abstract: In a streaming current signal, a zero crossing circuit tracks the phase of the streaming current signal. A latch is clocked in response to the outputs of the zero crossing signal to compensate the piston direction signal for change of phase of the streaming current signal.

Abstract: A streaming current detector has a reciprocating piston with a sensing region having a uniform clearance from the casing which is sufficiently large to avoid significant shearing of the particles in the fluid of the sample stream. A separate guiding region of the piston has a sufficiently tight fit in the casing for smooth reciprocation. A relief region of the piston has the largest clearance from the casing to provide a sufficiently large area to control a constant low velocity of the sample fluid.

Abstract: A streaming current detector having a probe with an electrode holder which can be removed and replaced within only about one minute, allowing the probe to be kept on line nearly continuously even in highly contaminated wastewater. The probe also includes a reciprocating piston and a housing with both a cylindrical void and a transverse passageway. In assembled relation, the electrode holder is slidably disposed within the cylindrical void; and the piston is slidably engaged with an inner wall of the electrode holder. Capillary-sized channels formed between this inner wall and the piston communicate fluidly with the transverse passageway. From it, any test flow stream present is partially sucked into the capillary-sized channels during an upstroke of the piston and then expelled from them, back into the transverse passageway, during the succeeding downstroke.

Abstract: A method for the determination of particle size and electric charge or zeta potential of particles dispersed in a fluid medium. The particle size and charge are determined from measurements of (1) the phase lag between an applied alternating electric field and the resulting particle velocity, and (2) the amplitude of the particle velocity. Also disclosed is the measurement of the interaction of sound waves and electric fields in the fluid medium over a range of frequencies to obtain the particle size and zeta potential.

Abstract: A static induction electric apparatus includes an oil tank, an electrical winding assembly, an insulating oil for cooling and insulating the winding, and a circulating pump. A sensor electrode having a measurement surface for providing an electrical signal indicative of the amount of the electric charge in the insulating oil is supported on the oil tank by a support assembly in such a relationship that the measurement surface of the sensor electrode is electrically insulated from and substantially flush with the inner surface of the oil tank. The distance between the sensing surface of the electrode and the inner surface of the oil tank is large enough to electrically insulate the two from one another but small enough to keep the electric field around the sensor electrode free of substantial disturbances.

Abstract: A method and apparatus for defining the molecular chemical make up of a liquid sample, based on electrostatic charges of emission. Three spaced electrodes are brought into contact with the surface of a liquid to be tested. Two electrodes are wired in series through a usual cone speaker to the terminals of an audio amplifier. A third electrode is wired in series through a variable oscillator to the amplifier auxiliary input terminal. This overall regenerative feedback circuit will result in unique patterns of coded pulses at the amplifier speaker output corresponding to the composition of the liquid, which can be observed on an oscilloscope or recorded and compared with known compositions. This apparatus can be useful in defining molecular diseases when the electrodes are touched to the wetted skin of an animal, plant tissue or blood sample. The apparatus can also be adapted to a neological method of electronic gene mapping.

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 bypass conduit is connected to a primary conduit and has tandem reservoirs formed therein. Continuous measurements are taken from the respective reservoirs of the electrical current generated by the relaxing fluid therein and flowing to ground. These respective measurements are inputted to a microcomputer through respective electrometer elements and converted into a single measure of charge density along with readings of the moisture, conductivity and temperature of the fluid. In a preferred embodiment, the fluid constitutes the oil (or other coolant) circulated in respective conduits between a power transformer and an external heat exchanger. The microcomputer may trigger an alarm (or a control mechanism) whenever the charge density generated in the circulating coolant reaches a predetermined threshold level, thereby avoiding a potential hazardous condition due to the build-up of static electrical charges in the protected transformer or other device.

Abstract: A method and apparatus for classifying non-aqueous liquid suspensions of charged particles employs a large time-varying electric field applied to a suspension situated between capacitive test electrodes. A current waveform is produced that characterizes the suspension with respect to critical properties including concentration, mobility, and plating tendencies of the charged particles suspended therein. The approach is suitable for use with suspensions having relative permitivity constants of about 15 or less.

Abstract: The density of charge entrained in fluids such as oils in transformer systems, capacitors, cables, pumps and fuel transfer systems is measured by introducing the oil into a conductive container which expands in volume to receive the fluid without expelling any fluid. The container is shielded by a grounded conductor which prevents inducement of charge on the container by external sources. By measuring the current between the conducting expandable container and the surrounding shield and accounting for the effects of the charge induced on the outer wall of the container by its own induced voltage, the net charge entrained in the fluid as it is brought into the container is deduced. Extraneous effects of conduction and electrokinetic currents are automatically excluded from the measurement. The oil is then automatically returned to the transformer system by the contraction of the conductive container so that the measurement can be repeated without accumulating an inventory of fluid.

Abstract: A streaming current detector includes an optical shutter rotated by the shaft of the motor which reciprocates a piston between electrodes in a bore containing sample fluid. An electronic synchronous detector is controlled by the output of a light detector whose source is interrupted by the optical shutter. The alternating current signals from the electrodes are connected to an operational amplifier having its inverting input connected to its output solely by a capacitor so that the output voltage is proportional to the charge of the fluid.

Abstract: An electrodeless apparatus for determining a function of the electrical charge condition in a flowable liquid media containing electrical charge influencing species comprising a tubular flow path member, the flow path member having electrically insulating walls, an open end and a closed end, the flow path being so disposed that it may be substantially filled with the liquid, a reciprocating member whose outer wall is electrically insulating disposed within the flow path member, the reciprocating member having a transverse cross-sectional configuration such that the reciprocating member fits adjacent but spaced from the electrically insulating walls of the flow path member, an annulus for admitting predetermined amounts of flowable material to the flow path member, a sensor disposed on the non-wetted side of the flow path member for developing a signal proportional to a desired ion activity by electrostatic or inductive coupling, and means coupled to said sensor for amplifying any electrical signal induced acr

Abstract: Flow velocity measurement apparatus for cryogenic liquid flowing in a pipe (1) past spaced upstream (12) and downstream (14) electrodes with triboelectric, flow-generated determined signals at the electrodes directed to a cross-correlator (2) which shifts the time bases of the signals relative to each other and reiteratively multiplies the shifted signals until a maximum multiplication product is achieved, the time shift associated with such maximum being flow transit time between the electrodes.

Abstract: A streaming current detector which utilizes the test flow stream to keep the electrodes of the detector probe washed and its dielectric surfaces from becoming fouled. The test stream first enters a housing surrounding the probe at a position proximate the inlet to a transverse passageway within the probe. Most of the flow moves directly through the probe along the transverse passageway, but a small portion of this flow is sucked into capillary-sized channels within the probe by the action of a piston during its upstroke and then expelled from them back into the transverse passageway during the downstroke. The flow leaving the transverse passage plummets downwardly where it joins a smaller fraction of the test stream that did not enter the transverse passageway and together they are discharged out the bottom of the housing. There are no low velocity or stagnate areas where solids can accumulate either in the housing surrounding the probe or within the probe itself.

Abstract: To measure potential differences in second-class conductors without interference potentials, there are provided a potential generator cooperating with a potential-measuring structure. This structure includes a substrate of electrically highly insulating and chemically inert material embedding optical indicators whose optical properties change as a function of the applied electric potential difference. Both the potential generator and the potential-measuring structure have boundary surfaces which are in contact with the second-class conductor and opposite surfaces interconnected by an equalizing conductor. A light-measuring device is arranged for intercepting light changes in the indicators, thus measuring the potential difference.

Abstract: An empirical method for the remote sensing of steam quality that can be easily adapted to downhole steam quality measurements by measuring the electrical properties of two-phase flow across electrode grids at low frequencies.

Abstract: Apparatus for measuring the concentration of solid particles in a fluid stream wherein a critical flow orifice produces a stream of fluid having a constant velocity, a surface for effecting triboelectric charging of the particles in the gas in the constant velocity stream and a charge measuring device for measuring the charges thus triboelectrically imparted to the particles. The apparatus overcomes the inaccuracies which occur in prior art particle detectors when such particle detectors are used to monitor fluid streams whose velocity is variable e.g. air intake systems for internal combustion engines which operate at varying speeds.

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: An element interacting with a stream of a fluid moving through a pipe generates periodic sub-flows at a rate that varies in accordance with changes in the velocity of the moving fluid. The generation of sub-flows also modulates the electrical charges contained in and moving with the fluid thus permitting a detector which is responsive to the energy being radiated by the modulated charges to produce a sensor signal having a frequency corresponding to the generating rate of the periodically produced sub-flows. In one preferred embodiment, the element is a vortex-shedding body and the sub-flows are vortices being shed therefrom. Electrical circuitry which receives the sensor signal converts it into a flow signal representative of the velocity of the moving fluid.

Abstract: A flow rate detection device is constructed so that electrodes for forming an electric field whose intensity spatially changes along a stream of a dielectric fluid are coaxially arranged, and a current detecting means measures a dielectric polarization current flowing when the dielectric fluid flows between the electrodes which form the electric field. The device can detect even a flow rate having a large change therein, for example, of an intermittently flowing stream, and is suitable as a device for measuring a flow rate of a fuel.

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

Abstract: An ultrasonic streaming current detector for developing, on a continuous basis, an electric signal which is a function of the charge condition existing in a stream containing charged particles. The present invention has a cross shaped housing having a cross member and a longitudinal member containing a pump chamber having a reciprocating piston on a pair of signal generating electrodes. A fluid injection connection is provided to the base of the longtudinal member. The piston pumps a sample stream within the pump chamber, creating a reciprocating shear force against the sample stream, generating an electric signal across the electrodes. The generated signal is representative of the average electric charge of the suspended particles in the sample stream. To prevent buildup of sample particles in the pump chamber, which would bias the signal, a periodic wash backflow of a fluid is injected into the pump chamber, preferably at a point opposite the point of sample fluid injection.

Abstract: An ultrasonic streaming current detector for developing on a continuous basis, electrical signal which is a function of the charge condition existing in the stream containing charged particles therein, for thereby facilitating the determination of the dosage of floculate to be added to a charge implacing species field stream, for thereby ultimately controlling floculation of such streams. The present invention employs a cross-shaped housing having cross-member and a longitudinal member, a piston receiving member, a reciprocating piston, a pair of electrodes, a meter recorder and a electrical mortar. The piston pumps, the simple stream within its interior and by means of this reciprocating shear force against the simple stream generating an electrical signal across electrodes dispositioned at either end of the pump stroke of the piston to thereby generate an electrical signal through lead wires connected to a meter recorder box.

Abstract: Methods and apparatus for monitoring the condition of dielectric fluid used in EDM are described. A continuous sample of dielectric liquid is withdrawn from a tank containing the EDM electrode and workpiece and is passed between electrodes of a capacitance cell before being returned to the tank. The capacitance between the electrodes gives an indication of the amount of metal particles resulting from EDM in the dielectric liquid. In another arrangement a magnetic field is used to direct most ferrous particles through a capacitance cell or part of a capacitance cell while most non-ferrous particles pass through another cell or another part of the cell. Measurement of the capacities of the cells or parts of cells provides an indication of the relative amounts of ferrous and non-ferrous particles in the dielectric liquid.

Abstract: The flow velocity or flow rate of a fluid containing electrical charges or magnetic dipoles is sensed by receiving a noise signal generated by movement of the charges or dipoles, and determining the mean frequency of the received signal.

Abstract: A method and apparatus are disclosed for sensing the changes in the electrical potential across a double layer. By using a conductive plug comprised of the same material that are in suspension in a fluid, the present method can be used to determine the timing and amount of agents to be added to the liquid to promote the removal of the particle. In one embodiment, the sensor is comprised of two closed chambers, a sensor chamber closed by a porous plug made from the subject material, and a reference chamber closed by a plug that prevents particle dispersion therethrough and also offers a negligible variation in double layer interface potential. An exemplary plug could be comprised of agar. Each chamber includes a corresponding electrode probe and is filled with a conductive solution.

Abstract: An electrified fluid flows through a main pipe and its bypass line including a conducting pipe insulated from the remaining pipes and the main pipe. While the electrified fluid flows through the insulating pipe the latter acquires all electric charges which is, in turn, measured, as a current, by an ammeter connected between the insulated pipe and ground. A flow meter is disposed in the bypass line on the outgoing side of the insulated pipe and measures a flow rate. An electric charge density is calculated from the measured current and flow rate.

Abstract: A sensor and method are disclosed for measuring electrokinetic effects across a double layer formed at the boundary between a solid wall and an ionic liquid flowing through a channel. In one embodiment, a passive electrode is located in a cavity forming a tee section with the channel through an orifice of approximately the same size as the channel. A passive second electrode in electrical communication with one side of the double layer is placed on the other side of a porous plug which is located in a second cavity directly opposite the orifice and which is flush with the channel walls. The double layer being investigated is formed on the flush portion of the porous plug. Thus both electrodes are out of the flowing liquid. An electrokinetic potential, labeled the K-effect potential, was measured by the two electrodes.