174results about "Permeability measurements" patented technology

A wireless sensing system monitors the level, temperature, magnetic permeability and electrical dielectric constant of a non-gaseous material in a container. An open-circuit electrical conductor is shaped to form a two-dimensional geometric pattern that can store and transfer electrical and magnetic energy. The conductor resonates in the presence of a time-varying magnetic field to generate a harmonic response. The conductor is mounted in an environmentally-sealed housing. A magnetic field response recorder wirelessly transmits the time-varying magnetic field to power the conductor, and wirelessly detects the harmonic response that is an indication of at least one of level of the material in the container, temperature of the material in the container, magnetic permeability of the material in the container, and dielectric constant of the material in the container.

An inspection tool for the non-destructive testing of a test component made of an electrically conductive material is described. The inspection tool employs movably mounted permanent magnets, which provides a means for generating a variable DC magnetic field within the test component, and eddy current probes so as to provide a means for performing a partial saturation eddy current test upon the test component. The eddy current probe preferably comprises an integrated magnetic field sensor which increases the accuracy and flexibility of the modes of operation of the described apparatus and methods. The described apparatus and methods are particularly suited for the inspection of tubular components that are often remotely located within the oil and gas exploration and production industries.

A process control method is described which uses measurements from magnetic field sensors to monitor the condition of material, such as from a heat treatment process. The sensors can be single element sensors or sensor arrays, can be used to periodically inspect selected locations, mounted to the test material, or scanned over the test material to generate two-dimensional images of the material properties. The sensors can be exposed to the same process conditions as the material, such as elevated temperatures, or the shielding layers can be placed between the test material and the sensors to reduce sensor exposure to the processing conditions. Additional property measurements, such as sensor lift-off, can be used to ensure proper sensors operation.

A common source double-frequency excitation type multifunctional micro-magnetic signal synchronous detection method is disclosed and belongs to the technical field of micro-magnetic nondestructive testing. Via use of the common source double-frequency excitation type multifunctional micro-magnetic signal synchronous detection method, five types of typical micro-magnetic detection parameters can be obtained synchronously, and detecting efficiency can be greatly improved. A standard micro-magnetic probe comprises an excitation magnetic circuit consisting of a magnetic core and an excitation wire coil, an induction wire coil wounded around the magnetic core, a Hall element used for detecting surface tangential magnetic field change of a ferromagnetic component being detected, and a Barkhausen noise detection wire coil. Sine wave superposed signals having a low frequency less than 100 Hz and a high frequency greater than 1k Hz that matche with an amplitude ration are used as excitation signals, and the excitation signals are sent into the excitation wire coil of the standard micro-magnetic probe so as to magnetize the ferromagnetic component being detected. The induction wire coil, the Hall element and the Barkhausen noise detection wire coil are respectively used for synchronously picking characteristic signals such as magnetic induction intensity time-varying signals, tangential magnetic field detection signals and Barkhausen noise detection signals; magnetic hysteresis loops, tangential magnetic field intensity time-varying signals, Barkhausen noise, eddy current impedance and incremental magnetic permeability can be quickly detected.

The invention relates to a method for measuring the magnetic permeability of a magnetic material by measuring the magnetic interaction of an electromagnetic field with this material by using a measuring device including a measuring cell connected through a microwave frequency cable (13) to a vector network analyser (12), said method comprising steps for gauging/calibrating said measuring device, for determining corrective coefficients to be applied to the measurements obtained by means of this device, for verifying the non-drift of this device, these steps being carried out with the help of a reference sample, wherein a reference sample is used, comprising at least one inclusion which enables creation, in a given volume, of a local artificial permeability, each inclusion being achieved by combining at least one inductive component possibly associated with a combination of at last one capacitive and/or resistive and/or active component, the frequency response of the electromagnetic properties of each volume being adjusted by the value and the assembly architecture of the components.

The invention also relates to such a reference sample.

A micro-magnetic detecting method includes the steps of: detecting a magnetic induction intensity along a first direction on a surface of a detected object to generate a detection signal, determining whether an amplitude of the detection signal is an anomalous value at a first position of the surface of the detected object, wherein the anomalous value is a value which is inconsistent with a linear value of the detection signal at the first position, and the linear value is a value that satisfies a linear relationship of the detection signal, and determining there is a defect at the first position of the detected object in case that the amplitude of the detection signal is the anomalous value. Accordingly, it detects the magnetic induction intensity on the surface of the detected object so as to detect its surface and internal defects when it remains in its original status.

The invention discloses a microwave sensor for synchronously measuring a dielectric constant and magnetic conductivity of a magnetic medium material. The microwave sensor comprises two microstrip linestructures, a medium layer, a metal sheet and two slotted metal CSRR (complementary split-ring resonator) structures from a top layer to a bottom layer. Each slotted metal CSRR structure is composedof an inner slot ring and an outer slot ring, wherein each of the inner slot ring and the outer slot ring is provided with an opening, and facing directions of the openings are identical; two oppositeright angles of the opening of the inner slot ring and two opposite right angles of the opening of the outer slot ring are all folded inwards in an alignment mode, and the opening of the outer slot ring extends towards the inside and outside of the outer slot ring to form channels; the part between the channels of the opening of the outer slot ring is a region with maximum magnetic field intensity, and the region is used to contain a to-be-detected sample for measuring the magnetic conductivity of the sample; and the part between the channels, where the two inwards-folded right angles of theinner slot ring and the two inwards-folded right angles of the outer slot ring are connected, is a region with maximum electric field intensity, and the region is used to contain the to-be-detected sample for measuring the dielectric constant of the sample. According to the microwave sensor, the form of a differential structure is adopted, differential measurement can be performed on the dielectric constant and the magnetic conductivity, and the influence of environment factors is eliminated by the adoption of a relative measurement mode.

The invention provides a sensor used for magnetic conductivity measurement. The sensor comprises a four-tap solenoid coil. Four taps are led out of the solenoid coil from the top to the bottom in turn. The first tap of the four taps is connected with an excitation current source which is connected with the ground. The fourth tap is connected with the ground potential of the excitation current source so as to form a current loop. The second tap and the third tap are connected with the input end of an instrument amplifier to acquire differential voltage and connected with a voltage measurement module. The invention also provides a measurement method using the sensor used for magnetic conductivity measurement. The effects of the sensor used for magnetic conductivity measurement are that the four-tap solenoid sensor is simple and feasible and can directly measure the magnetic conductivity of particle/powder material without preparing a magnetic core of the specific shape in advance; the physical model of the sensor is clear, and the relational expression between the induction value and the measured medium magnetic conductivity can be determined by the analytic formula so that structural optimization and parameter correction are facilitated; and the middle tap performs measurement so that the influence of the edge effect of the two ends of the solenoid can be avoided and the more accurate measurement result can be acquired.

The invention relates to a magneto resistance sensor-based magnetic conductivity electromagnetic tomography system. An electromagnetic imaging sensor is adopted as the sensor of the magneto resistance sensor-based magnetic permeability tomography system; the electromagnetic imaging sensor comprises M excitation coils, N pairs of magneto resistance sensors and an electromagnetic shielding layer, wherein the excitation coils and the magneto resistance sensors are arranged in the electromagnetic shielding layer; each excitation coil is provided with a separate excitation channel; the excitation coils are arranged on the same section outside a cylindrical object field region; the magneto resistance sensor pairs are also arranged on the same section; the excitation coils and the magneto resistance sensors are arranged on different circles; and each pair of magneto resistance sensors is located inside a certain excitation coil. Under the control of a control module, an excitation signal generation and power amplification unit generates excitation signals with different amplitudes and frequencies; the excitation signals are connected onto the designated excitation coils through a multi-channel gating switch; signals outputted by the magneto resistance sensors pass through the gating switch and are transmitted to the control module through a signal conditioning and acquisition unit; the control module demodulates the signals; and the demodulate signals are transmitted to an upper computer through a communication module.

A thermomagnetic sensor includes a thermomagnetic probe that includes a ferromagnetic material having a temperature-dependent magnetic permeability characterized by a maximum magnetic permeability value at a temperature below a Curie temperature of the ferromagnetic material. The thermomagnetic sensor further includes an alternating magnetic field source to produce an alternating magnetic field in a vicinity of the thermomagnetic probe to facilitate a measurement of the temperature-dependent magnetic permeability as function of temperature remotely using a thermomagnetic effect. A predetermined relationship between the temperature-dependent magnetic permeability and temperature in a range between the maximum magnetic permeability value and the Curie temperature provides a measurement of a temperature local to the thermomagnetic probe. A battery-temperature measurement system includes the thermomagnetic probe in a battery, a magnetic field coil to apply the alternating magnetic field, and a magnetic permeability measurement apparatus to measure the temperature-dependent magnetic permeability.

The process determines the permeability of the magnetic material by disturbance of a hyper frequency coaxial line. In the process, a sample of the material is formed and placed in a hyper frequency coaxial line. The reflection and/or transmission of a hyper frequency electromagnetic wave on and/or through this coaxial line is measured and the result of this measurement is used to deduce the magnetic permeability of the material. The fractional volume of magnetic material in the sample compared with the volume of the disturbed coaxial line is less than 1%.

A method for detecting complex permittivity of a nano film by virtue of a multifunctional rectangular cavity perturbation method relates to the field of detection of material performance parameters. The nano film chip-type material measuring device contains a rectangular cavity sensor, a microwave vector network analyzer, an input coaxial cable, an output coaxial cable, a GPIB data acquisition card and a computer. The method provided by the invention can detect complex permittivity (permittivity and a dielectric loss coefficient) of a pure dielectric material, complex permeability (permeability and a magnetic loss coefficient) of a pure magnetic material and complex permittivity (permittivity, a dielectric loss coefficient, permeability and a magnetic loss coefficient) of a mixed dielectric material, has multiple functions and multiple modes and is high in accuracy and easy in experimental operation.

The invention discloses a phase angle amplitude PID adaptive method based on three-dimensional magnetic characteristic measurement of BP neural network. In the process of signal processing, adopting afrequency domain approach, compared with the time domain method, the harmonics are decomposed into frequency domain, the amplitude and phase angles are independently closed-loop controlled, as the amplitude is traversed to minimize the error between the output voltage and the desired voltage, then the phase angle is found to minimize the output error, PID can quickly find the appropriate amplitude and phase angle, so that the output waveform vector in three directions is a standard spherical or ellipsoidal after synthesis, so that the actual waveform can quickly and accurately approximate thedesired waveform. When the excitation frequency and amplitude change, the weights of the hidden layer and the output layer of the neural network change correspondingly, so that the PID parameters canbe adaptively changed with the feedback adjustment process of the waveform, so that the rapidity and accuracy of the magnetic measurement process are greatly improved, and the response time is greatly reduced.