488results about "Fluid resistance measurements" patented technology

A method and apparatus are disclosed for determining the concentration of individual components within a fluid mixture by determining the permittivity of the individual components. The method and apparatus use a reference sensor and at least one measurement sensor positioned inside the same sensor device that is immersed in the fluid mixture to be measured. Signals, such as radio frequency or microwave, are sequentially transmitted at multiple, known, constant frequencies to and reflected from both the reference and measurement sensor(s). Permittivities of the individual components are determined from these transmitted and reflected signals and information about the concentration of the individual fluids and other compounds within the fluid mixture and the density of the fluid mixture are produced. Repetitive sampling and processing of these signals allow determination and real-time monitoring of the concentration of individual components within a mixture of fluids. The present invention provides self-calibration, accurate frequency maintenance and self-selection of an operating frequency range.

The method comprises: using a AC square wave current with a certain frequency (FH) to excite the electrode through a cable; making a synchronous detection for the response voltage waveform of the electrode to get a first mean voltage value; the first mean voltage value is divided by the current amplitude to get the resistance value (RH) of the first view; using a AC square wave current in another frequency (FL) to excite the electrode through a cable to make synchronous detection for the response voltage waveform to get a second mean voltage value; the second mean voltage value is divided by the current amplitude to get the resistance value (RL) of the second view; based on a mathematical model, getting the ratio relation of the inter-electrode resistance R to the RH, RL and FH, FL; based on it, getting the inter-electrode resistance value R; according to the electrode constant, getting the conductivity of the solution under test.

A conductivity detector detects the electrical conductivity of a fluid under analysis for determining chemical or physical properties of the fluid that are related its electrical properties. Such conductivity detectors may find use in, for example, hemodialysis systems for analyzing the effectiveness of the hemodialysis treatment. In an aspect, to improve accuracy of the conductivity measurements, the detector utilizes four-wire resistance measurement methods. In another aspect, to avoid fouling or contamination of the electrodes, the detector utilizes capacitively-coupled contactless conductivity detection (C4D) methods so that the electrodes are physically unconnected to the fluid contained in a fluid chamber. In a possible further aspect, the fluid chamber may be a disposable component removable from the electrodes. The conductivity detector can include other features such as calibration circuits and features for electrically isolating the fluid under detection from the fluid in the rest of the system.

A sensor, a system of direct measurement using that sensor, and a method of direct and simultaneous measurement of conductivity and dielectric constant of a fluid, particularly high impedance, hydrocarbon-based fluids. The sensor has a cell that holds the fluids to be measured between a single pair of coaxial, bare metal electrodes connected through interface circuitry to measurement circuitry preferably implemented in one or several IC's. The sensor has a mutually compatible electrode geometry that provides both the correct cell constant for measurement of conductivity of hydrocarbons fluids (typical range 0-100,000 pS / cm), and a bulk capacitance (for use in dielectric constant measurement) in the range of measure of readily available low cost commercial IC's (having a typical capacitance measurement span of <10 pF, with a total bulk capacitance at the chip of <20 pF). The cell conductivity constant for use with hydrocarbon-based oils having a conductivity in the range of 1 to 500,000 pS / M is preferably less than or equal to about 0.1. The cell bulk capacitance with hydrocarbon fluids inside the sensor results in a bulk capacitance of at least about 4 pF. In one embodiment, the electronic circuitry is a Microcontroller / DSP that both generates synchronous drive signals at various frequencies, for both conductivity and dielectric constant measurements while directly digitizing and numerically processing the sensor output.

A multi-sensor as disclosed herein can include a substrate and at least three sensing elements disposed on the substrate. Each sensing element includes two electrodes separated by a distance and a nanowire mat adjacent to and in contact with the electrodes. The nanowire mats include nanowires which define a percolation network. The density of the nanowires in the nanowire mat of one sensing element is different than the density of the nanowires in the nanowire mat of either of the other at least two sensing elements.

The present invention is directed toward oxidation-resistant, ligand-capped nanoparticles, each comprising one or more capping ligands on a copper-containing core. Methods of making and using these nanoparticles are also disclosed.

Methods and systems for improving the sensitivity of a variety of conductivity sensing devices, in particular capacitively-coupled contactless conductivity detectors. A parallel inductor is added to the conductivity sensor. The sensor with the parallel inductor is operated at a resonant frequency of the equivalent circuit model. At the resonant frequency, parasitic capacitances that are either in series or in parallel with the conductance (and possibly a series resistance) is substantially removed from the equivalent circuit, leaving a purely resistive impedance. An appreciably higher sensor sensitivity results. Experimental verification shows that sensitivity improvements of the order of 10,000-fold are possible. Examples of detecting particulates with high precision by application of the apparatus and methods of operation are described.

A logging-while-drilling tool is adapted for incorporation with a drill string having a longitudinal axis. The drill string is further adapted for drilling a wellbore penetrating a geological formation. The drilling tool includes a tool body having a central axis disposed in parallel relation with the longitudinal axis of the drill string and an external, circumferential surface spaced radially outward from the central axis. The tool also includes a measurement apparatus for measuring resistivity of a borehole fluid in the wellbore. The measurement apparatus has an electrode array including a current emitting electrode disposed on the circumferential surface. The current emitting electrode is adapted to emit current into a target region of the wellbore spaced laterally between the circumferential surface and the walls of the wellbore. Further, a current receiving electrode is disposed on the circumferential surface and spaced apart from the current emitting electrode. The current receiving electrode is adapted to receive current propagated from the current emitting electrode into the target region. The electrode array occupies an arcuate section of the circumferential surface that extends less than about 180° about the central axis.

A method is disclosed for downhole determination of the resistivity of fluids from formations surrounding an earth borehole, including the following steps: providing a formation testing logging device that includes a coil and a flow line passing axially through the coil; determining a reference quality factor of the coil; positioning the formation testing device in the borehole, and causing formation fluid to flow through the flow line; measuring the quality factor of the coil with formation fluid in the flow line; and determining the resistivity of the formation fluid in the flow line as a function of the measured quality factor and the reference quality factor.

The present invention disclosed a method for measuring electric conductivity of water. It is characterized by that said method includes the following steps: adopting a conductance tank with two electrodes; respectively applying sine signals whose frequencies are omega a and omega b, in which omega b=2 omega a; respectively measuring modulus of Za and Zb of impedance under the condition of two frequencies; and utilizing a formula to determine its conductivity value g. Said invention also provides said formula.

A method for investigating a target environment to determine whether or in what amount a chemical species may be present therein, which comprises: (a) exposing to said environment an article of manufacture comprising a multiplicity of particles in close-packed orientation, said particles having a core of conductive metal or conductive metal alloy and deposited thereon a ligand which is capable of interacting with said species such that a property of said multiplicity of particles is altered; (b) subjecting said multiplicity of particles to conditions sufficient for said property to be exhibited; and (c) monitoring said property to determine whether there is, or the amount of, any change as an indication of whether, or in what amount, said species is present; a multiplicity of particles suitable for use in such method; and equipment suitable for implementing the method.

A method of noncontact measuring the electrical conductivity of electrolytes using a primary measuring transformer includes placing the electrolyte in a sampler, exciting an alternating magnetic field using an axisymmetrical eddy current sensor, switching to the sensor a capacitor of variable capacitance, tuning of the formed circuit in resonance with the frequency of the generator of harmonic oscillations, and recording the change in the introduced active resistance of the parametric eddy current sensor rated against its own inductive resistance.

The invention discloses a capacitor coupling noncontact conductance measurement device and method. The device comprises an alternating-current excitation source, an insulated measurement pipeline, an excitation electrode, a detection electrode, a range resistor, a virtual inductor, a differential amplifier module and a signal processing module, wherein one end of the virtual inductor is connected with the range resistor, while the other end is grounded, meanwhile, two ends of the range resistor are connected with the differential amplifier module. The virtual inductor substitutes an actual inductor, thus effectively overcoming the adverse effect of a coupled capacitor on the measurement result according to the series resonance principle. The virtual inductor is a grounding inductor, and compared with a floating inductor, the virtual inductor is good in working stability and simple in circuit structure; compared with an actual inductor, the virtual inductor capable of adjusting the equivalent inductance value reduces the requirement for the frequency of the excitation source. In addition, different from a noncontact conductance measurement method adopting a current method, the capacitor coupling noncontact conductance measurement method adopts a voltage method to obtain the equivalent conductance value of measured conductive fluid, thus providing helpful reference for solving the conductance measurement problem of conductive fluid in a pipeline.

An apparatus for measuring fluid resistivity includes a flow line adapted to be in fluid communication with formation fluids, wherein the flow line includes a first section comprising a first conductive area, a second section comprising a second conductive area, and an insulating section disposed between the first section and the second section to prevent direct electrical communication between the first section and the second section; a first toroid and a second toroid surrounding the flow line around the first section and the second section, respectively, wherein the first toroid is configured to induce an electrical current in a fluid in the flow line and the second toroid is configured to measure the electrical current induced in the fluid in the flow line; and an electronic package to control functions of the first toroid and the second toroid.

The invention relates to a conductivity sensor, comprising an electrode structure of four concentric electrodes (5, 6, 7, and 8), which are arranged on an end face (4) of a support body (2). The electrodes (5, 6, 7, and 8) are electrically insulated from one another. The electrodes (5, 6, 7, and 8) have an equal, constant area in order to claim a space requirement as small as possible for the electrode structure.

A conductivity counter and method of determining conductivity of a fluid sample are disclosed. The counter is suitable for high-speed, accurate counting of discrete events or items, such as cancer cells, passing through a fluid sample cell. A variable frequency current source is used to supply an excitation current to a sample cell connected in parallel with an inductance or the electrical equivalence of an inductance. This configuration can be accurately modeled as a parallel RLC circuit when the system is operated at a stable frequency. The current source frequency is tuned to the resonance frequency of the equivalent RLC circuit, which effectively eliminates the capacitive and inductive components of the impedance, leaving only purely resistive components. The output of the equivalent RLC circuit is connected to a high input impedance buffer amplifier and then to a phase sensitive detector, which detects the phase shift resulting from the equivalent RLC circuit. The output is filtered and a differencing amplifier is used to zero out the output signal due to the system components and the sample cell buffer solution prior to taking active readings. The remaining output signal is due to perturbations in the fluid sample, such as passing cancer cells. This output is sent to a high-gain output amplifier and then supplied to a suitable signal processing device or system, such as a computer.

This invention relates to a measurement method for solution conductivity, which applies an AC signal source with a semi-cycle pulse width of t to the two poles of a conduction tank to compute the conductivity or resistivity by testing the value of a X< 1 > signal of the tank at T< X1 > in the sphere of any semi-cycle 0-49%t and the value of X< 2 > at T< X2 > in the sphere of any semi-cycle 51-100% t. In this invention, when the value of X< 1 > / X< 2 > is greater than a pre-designed upper limit value or the value of X< 2 > / X< 1 > is smaller than a pre-designed lower limit, it puts forward test alarms to ask for exchanging the conduction poles of even larger conduction tank constant for even stable test to avoid measurement with greater errors.

A conductivity detector detects the electrical conductivity of a fluid under analysis for determining chemical or physical properties of the fluid that are related its electrical properties. Such conductivity detectors may find use in, for example, hemodialysis systems for analyzing the effectiveness of the hemodialysis treatment. In an aspect, to improve accuracy of the conductivity measurements, the detector utilizes four-wire resistance measurement methods. In another aspect, to avoid fouling or contamination of the electrodes, the detector utilizes capacitively-coupled contactless conductivity detection (C4D) methods so that the electrodes are physically unconnected to the fluid contained in a fluid chamber. In a possible further aspect, the fluid chamber may be a disposable component removable from the electrodes. The conductivity detector can include other features such as calibration circuits and features for electrically isolating the fluid under detection from the fluid in the rest of the system.

Low power corrosion measurement devices are described with improved LPR, HDA, and ECN measurement capabilities in a field transmitter for online corrosion monitoring or off-line corrosion data logging.

The present invention provides an apparatus and method for measuring the conductivity of a fluid employing the differential radio frequency phase detection between two embedded toroidal coils.

A shock detector having an electrical detector having a set of water immersible electrodes for detecting hazardous water conditions through the determination of the presence of either an electrical current in a body of water, a voltage in the body of water or a voltage gradient in the body of water and then providing an alert to the existence of hazardous electrical conditions in the body of water which in some cases may transmitted to a power source to shut off a power source thereby removing the hazardous water condition.

A method for measuring the electric conductivity of a solution includes measuring voltage and current, calculating active value, deriving the calculation equation of electric conductivity, and calculation. Electric conductivity of solution is indirectly calculated by measuring consumption W of solution.

The invention provides a high-temperature melt physical property measuring device which comprises a physical property measuring system, a heating furnace, a lifting system, a vacuum and atmosphere control system, a temperature control system and a control display system.The physical property measuring system is used for obtaining measured data, the heating furnace is used for providing the data extraction environment, the lifting system is used for controlling the relative position of the physical property measuring system and the heating furnace, the vacuum and atmosphere control system is used for ensuring that the reaction atmosphere and pressure of the physical measuring system and the heating furnace are consistent, the temperature control system is used for controlling the reaction temperature in the heating furnace, and the control display system is used for processing the measured data and calculating and displaying high-temperature melt physical properties.The device can ensure that viscosity, density, surface tension and specific conductance of a high-temperature melt are rapidly and precisely measured at good heating rate under precise temperature control.

An improved flow-through conductivity sensor is provided. The sensor includes a current return path that has a current return conductor. At least one toroid of the sensor is removed from the flow path and configured to interact with the current return conductor to provide an indication of conductivity. Additional aspects of the invention include disposing a pair of toroids about the current return conductor; disposing a toroid about the current return conductor and configuring the toroid as a transformer.

A system and related method are provided to calibrate for wire capacitance during use to minimize error in conductivity measurement of the target fluid. The system includes a signal generator configured to drive the conductivity cell and the temperature element, with an alternative current (AC) drive signal having variable parameter. The system further includes a processor assembly electrically coupled to the conductivity cell and the temperature element to calculate a conductivity value of the fluid. The conductivity value is a function of the values of the temperature measurement, the compensation measurement, and the raw conductivity measurement, thereby compensating the conductivity value for capacitance effects. In this manner, the system effectively compensates for capacitance attributable to wiring extending between the electrode and other electronics of the sensor, usable with wiring of varied and unknown lengths.

An osmolarity measuring system is configured to receive a contact lens in a measurement chamber. The measurement chamber includes a volume of fluid, and a series of electrodes are configured to measure the electrical properties of the fluid. A processing device correlates the measured electrical properties with an osmolarity measurement. Further, the processing device is configured to track trends in stored osmolarity measurements and alert the user to take an action, including the cessation or alteration of product use.