283results about How to "Eliminate measurement effects" patented technology

An open natural gas leakage multiplex inspecting method and optical channel configuration, based on semiconductor laser absorbing spectrum method, relates to master case and open long optical channel system. The master case sets with electrical source socket, switch, fan, optical fiber linker and data transmission interface. The master case owns closed infrared semiconductor laser, semiconductor laser controller, phase-locked amplifier,signal generator,data collection disposal and control module, light switch, light switch driving circuit and infrared detector and connects with the locale optics system by optical fiber. Open optical system relates to integral optics telescope and more component angle reflector array and the former owns import optical fiber coupling implement and output optical fiber coupling implement. It achieves the time-sharing inspect of more gas component and more multiplex based on optical fiber distributing configuration of the light switch technology.

The portable non-destructive plant nitrogen and water content detection system includes four wavelength spectral measurement device with oppositely set light source and detector, neutralized reference sample or leaf to be measured, micro controller connected to the light source and the detector, serial port circuit connected electrically to the micro controller, and display and keyboard connected electrically to the micro controller too. The detection method includes detecting data I0 and I, calculating the fresh leaf transmission T= I / I0 of different wavelengths, and calculating the plant chlorophyll, water content and relative content NI reflecting the nitrogen level in the leaf in chemical metering algorithm. Compared with traditional measurement method, the present invention has decades times raised efficiency and no production of environment harming matter, and may be used in great area fast field measurement.

The invention discloses a contact type temperature non-inductive three-dimensional detection sensor based on a fiber Bragg grating (FBG) and belongs to the technical field of precision instrument manufacturing and precision test measurement. The sensor comprises a broadband light source system which consists of a pump laser, a wavelength division multiplexing (WDM) coupler, an erbium-doped fiber and a beam splitter, a temperature compensation system which consists of an erbium-doped fiber amplifier (EDFA), a first circulator, a guide pipe, a reference FBG and a fiber barrier, a probe, and a signal receiving system which consists of an optical spectrum analyzer, a fiber coupler and an index-matching fluid, wherein the reference FBG of the temperature compensation system is arranged in a spatial distance of 30 cm of the probe. By the sensor, three-dimensional sensing is realized, and the environmental adaptability of the sensor is greatly improved. The sensor has the characteristics of simple structure and high real-time performance and is easy to practically use. The sensor has the advantage of quick and ultra-precise measurement and calibration of small cavity size.

The invention provides a device and method for measuring a micro-pore size based on a fiber Bragg grating and belongs to the technical fields of precision instrument manufacture and precision test metering. The device consists of an aiming and signaling device for generating aiming signals, a length measuring device for measuring the movement distance of a micro-pore to be measured within a time interval of measuring measurement starting and stopping signals which are sent by the aiming and signaling device, and a computer for controlling a measurement process of the entire measuring device. The method comprises the following steps of: continuously moving a working table along a direction vertical to a length measurement direction, and moving the working table along a measurement line to obtain a maximum displacement, relative to the micro-pore to be measured, of a probe, so as to obtain the diameter of the micro-pore to be measured. According to the device and method disclosed by the invention, the adaptability of the aiming and signaling device to the environment is greatly improved. The device disclosed by the invention has the characteristics of simple structure, good real-time capability and easiness for actual application, and has obvious advantage of carrying out rapid and ultra-precise measurement and aiming on the size of the micro-pore.

The invention provides a device and a method for improving the polarization-maintaining optical fiber polarization coupling measurement precision and the symmetry. The device comprises a wide-spectrum light source, a light signal controllable reversing mechanism, an optical fiber to be measured and a polarization coupling detection system, wherein the optical fiber to be measured is respectively connected between the wide-spectrum light source and the polarization coupling detection system in positive and opposite directions through the light signal controllable reversing mechanism, after low-coherence light emitted by the wide-spectrum light source enters the optical fiber to be measured through the light signal controllable reversing mechanism, transmission light and coupling light generated by the transmission light respectively enter the polarization coupling detection system, and the polarization-maintaining optical fiber polarization coupling point positions and amplitude information and the length of the optical fiber to be measured are obtained through calculating the signal amplitude and the scanning position of white light interference signals of the transmission light and the coupling light obtained in the polarization coupling detection system. The device and the method have very important practical value on the parameter measurement and the performance evaluation of optical fiber gyro sensitive rings and can also be widely applied to distributive polarization-maintaining optical fiber sensing systems.

The invention pertains to the technical field of fluid measurement, which relates to a slit Venturi throttle device, including an entrance, a contraction section, a slit section, an expansion section and an exit which are connected sequentially, the contraction section is a section of long narrow pipeline, the cross-section of the contraction section takes a shape of a long narrow rectangle, and the area of the cross section thereof is smaller than the area of the cross sections of the entrance and the exit. The invention also provides a two-phase flow measurement system which adopts the throttle device. The Venturi throttle device and the two-phase flow measurement system which are provided by the invention can effectively eliminate the influence of the friction pressure drop on the measurement, the devices can be applicable to the different gas-liquid two-phase media, different pipeline materials and other working conditions, and the factors which are related with the friction force and affect the measurement can be reduced or eliminated. The invention makes use of the gravity potential pressure difference pulse signals and the time equalization signals which are perpendicular to the horizontal flow direction, at the same time, the invention can avoid the influence of the frictional resistance and accurately identify the flow type and measure the fraction rate, furthermore, the implementation is simple and convenient.

The invention provides a gas-liquid two-phase flow metering device, which mainly comprises a cyclone, a rectifier, an ultrasonic probe, an ultrasonic Doppler velocimeter, a Pitot tube, a differential pressure transducer, a pressure transducer, a temperature transducer, a data acquisition computer, and the like. A flow metering method provided by the invention comprises the steps of separating a gas-liquid two-phase flow in a tube by means of the cyclone to form an annular liquid film region and a central gas region, measuring the liquid flow in a liquid film by means of the ultrasonic Doppler velocimeter, and measuring the gas flow by means of the Pitot tube. Compared with a multiphase flowmeter in the prior art, the above gas-liquid two-phase flow metering device is small in size, compact in structure, small in resistance loss, wide in measurement range, and high in measurement precision.

The invention belongs to the measurement technical field of atmosphere environment quality, which specifically relates to an online automatic measuring system for environment air quality based on low-temperature condensing method sampling. The system is composed of a low-temperature condensing sampling system and an analyzing system; the low-temperature condensing sampling system comprises a drying pipe, an electronic cold trap and a low-temperature low trap that are connected in turn; the drying pipe is connected with an air inlet pipeline for removing vapor and condensing the environment air sample at low temperature; the analyzing system comprises a light source, a sampling battery, an optical spectrum instrument and a computer; the analyzing system splits and detects the air condensed by the sampling system through the optical spectrum instrument by the ultraviolet function from the light source and then analyzes the air by the computer. The system is high in integrated degree and measuring efficiency, which is suitable for continuous, real-time and online measurement of various pollutants of atmosphere environment (including sulfur dioxide, nitrogen dioxide, ozone, ammonia, formaldehyde and part of benzene series) in environment air.

The invention relates to an on-line coal quality property detection device. The on-line coal quality property detection device is characterized by comprising a coal powder sampling subsystem, a coal powder cake pressing subsystem and a spectrum collecting and analyzing subsystem. According to the on-line coal quality property detection device, the coal powder sampling subsystem is firstly utilized to acquire low-rank coal powder from a wind powder pipeline installed between an exit of a coal mill of a coal-fired power generation unit and an entrance of a combustor, then the coal powder cake pressing subsystem is utilized to prepare the coal powder in a pressing mode into coal cakes specified in measurement requirements, and then a spectrum detecting system is utilized to detect the coal quality properties of the coal cakes. According to the on-line coal quantity property detection device, by performing cake pressing on the coal powder, the influence of the rough coal powder surface on measurement is eliminated, the overall device can easily achieve accurate and reliable on-line coal quality property detection in a spot environment, and therefore the device is beneficial for improving the burning efficiency of the coal-fired power generation unit and reducing pollutant discharging.

The invention discloses a simple and practical method for measuring frequency of alternating current voltage with software. The method comprises the following steps: acquiring a voltage value with a sampling time interval, carrying out discrete Fourier transform on the acquired voltage value, calculating a phase real part and a phase imaginary part of voltage, taking a product of the phase real part and the phase imaginary part as an input value of an interpolation fitting method, searching same direction zero crossing of the product of the phase real part and the phase imaginary part, and calculating frequency of the product of the phase real part and the phase imaginary part according to the zero crossing, wherein the frequency is the frequency of the alternating current voltage. According to the method, a filtering function of the discrete Fourier transform is fully utilized, influence of harmonic wave and direct current component on frequency measurement is eliminated, anti-interference capability is strong, a calculated value has high precision and small discrete, measurement precision is high, the method is simple and practical, high precision can be achieved both in stable state and transient state processes of a power system, realization of frequency measurement in a protection apparatus with a DSP as a core CPU is facilitated, and a requirement of the power system automatic field is satisfied.

The method uses at least each reference electrode to carry out measurement for pipe located position potential and for ground surface potential separately at the same time and instant interruption current method or additional applied eciting current signal method is applied to eliminate IP drop in the measuring course. The testing data collected by recorder is analysed by the microcomputer to confirm the true pipe located position potential and ground surface potential. The device to realize the method consists of reference electrode set, data collector recording device, signal generating device, current interrupt appliance, distance measurer and microcomputer analysis system, of which the signal generating device, current interrupt appliance and data collection recording device are set in synchronization with GPS.

The invention discloses a capacitance sensor, comprising a sensor gauge head, inner electrodes and an outer electrode, wherein the inner electrode is composed of a plurality of independent electrodes; the inner electrodes are the same in inner and outer diameters and are coaxially arrayed; the inner electrodes respectively comprise a top compensation electrode, a multi-section measurement electrode and a bottom compensation electrode from top to bottom; each two sections of electrodes are connected through a connecting piece which is made of an insulating material; the outer electrode is sleeved at the outer parts of the inner electrodes through screw threads, is coaxially mounted with the inner electrodes and is commonly shared by each section of the electrode in the inner electrodes; and the sensor gauge head is connected with the outer electrode. According to the capacitance sensor disclosed by the invention, the influences on liquid level measurement of temperature, pressure, mediums and the like are eliminated and the precision of the liquid level measurement is improved; and furthermore, an electricity leakage phenomenon can be effectively avoided and the linearity of the sensor is guaranteed.

The invention provides the frequency mixing biology impedance measurement method based on method of Fourier transformation, comprising the following steps: 1 defining parameters, getting checking path and reference path voltage signal sequence; 2 calculating with Fourier transformation; 3 reverting to path compensating calculation. The invention uses the method to get casting and phase angle of biology impedance information. The method uses computer to calculate, simplifying the hardware circuit, removing noise interference and improving the measurement accuracy. The method is based on the Fourier transformation demodulation calculation, directly carries out dispersion Fourier transformation for measured signal, and gets the biology impedance information. At the course of measuring, the method only adjusts sampling frequency, signal frequency and sampling points to directly measure, improving the measurement accuracy.

The invention discloses an impulse type laser ranging device and method, and belongs to the technical field of laser impulse ranging. The impulse type laser ranging device comprises a control module,a laser emitting module, an optical system module, a laser receiving module, a signal processing module, a timing module and a power supply module; the control module controls laser emitting, providesemitting start time for the timing module, and calculates a target ranging value based on impulse flight terminal time fed back by the timing module; and the signal processing module connected with the laser receiving module performs impulse decoding processing on a processed echo signal and identifies echo signal terminal time, namely, the impulse flight terminal time. The impulse type laser ranging device has high ranging precision and good reliability performance. Meanwhile, the invention further provides the impulse type laser ranging method based on the impulse type laser ranging device.According to the implementation, the problems that in the prior art, the precision of the impulse type laser ranging is low and the reliability performance is poor can be effectively improved.

The invention discloses a load rejection type deep sea oceanic turbulence mixing profile measuring instrument which comprises a recycling cabin and a load rejection cabin, wherein the load rejection cabin is arranged at the head part of the recycling cabin; the load rejection cabin comprises a load rejection releasing ring and a load rejection body; the load rejection body is connected with the recycling cabin through the load rejection releasing ring; a data measuring sensor is arranged on the load rejection body; a floater material block is arranged at the tail part of the recycling cabin; a positioning communication beacon is arranged on the floater material block; a main control unit, a data collecting unit and a posture control unit are arranged in the recycling cabin; the data collecting unit is connected with the data measuring sensor; the posture control unit is connected with the load rejection releasing ring; and the main control unit is respectively connected with the data collecting unit and the posture control unit. Without warping hawser, after being put into water, the load rejection type deep sea oceanic turbulence mixing profile measuring instrument can descend at a constant speed under the effect of gravity for observing, and the maximum working water depth of the instrument is 6000 meters, so that a new technical method is supplied for acquiring turbulence energy consumption and thermal dissipation data of deep sea areas and bottom boundary layers.

The invention discloses an emergency lighting cable pay-off and take-up length measuring device which comprises a reel controller, a cable reel and a winding displacement device. The reel controller controls rotation of the cable reel, a pulse identifier for identifying the rotation turn numbers of the cable reel is arranged on the cable reel, a proximity switch for identifying the pulse identifier is arranged on one side or two sides of the cable reel, position switches are arranged at two ends of the winding displacement device, both the proximity switch and the position switches are connected with the reel controller, and the reel controller is connected with a display module. The emergency lighting cable pay-off and take-up length measuring device gives consideration to the influence on the pay-off and take-up length of different layer numbers during winding, so that the cable pay-off and take-up length measurement is accurate. The influence on the measurement of cable diameter change caused by cable connection is eliminated, and the device is suitable for multiple-section cable connection. By combining a simple position detecting device and a proposed computing method, the cable length can be accurately measured in real time. The position detection of the reel is achieved by utilizing reinforcing ribs or detection holes of the cable reel, and the costs of the device are reduced.

The invention discloses a device and a method for measuring the shapes of spaces on the basis of low-reflectivity three-core fiber grating arrays, and belongs to technologies for manufacturing and measuring precision instruments. The device is structurally characterized in that a three-core fiber fan-out device is connected with an optical cable of a low-reflectivity three-core fiber Bragg grating array sensor, the optical cable of the low-reflectivity three-core fiber Bragg grating array sensor comprises a three-core fiber and a protective sleeve, fiber cores of the three-core fiber are uniformly configured, the protective sleeve is configured on the outside of the three-core fiber, and low-reflectivity fiber Bragg grating arrays are written on the three-core fiber. The method for measuring the shapes of the spaces includes measuring spectra by an optical frequency-domain reflectometer OFDR under the effects of a multi-way optical switch to acquire stress and temperature distribution of the low-reflectivity fiber Bragg grating arrays and optical cables of reference fiber Bragg grating arrays; decoupling influence of temperatures; reconstructing information of the shapes of the spaces. The optical cables of the reference fiber Bragg grating arrays are packaged in an outer stress isolation mode. The device and the method have the advantages that the device and the method are high in signal-to-noise ratio and precision and are insensible to environments, and the device can be attached onto the surfaces of measured components to measure the measured components in real time and is long in service life.

A plant morphometric parameter vision measuring instrument with the self-calibration function is provided. A high-resolution camera and a wide-angle lens are adopted to capture plant images in a non-contact manner and obtain measured parameter results by image processing, pattern recognition and numerical calculation. A ranging laser is adopted to detect the distance between the camera and the measured part and automatically correct and compensate, thus thoroughly overcoming the defect that the conventional measuring method has harsh requirements of the detection distance, and requires manual correction. A white LED light source is adopted to carry out active lighting, eliminate the impact of ambient light on the color parameter measurement and guarantee consistency and environmental suitability of the measurement results. A portable measuring instrument consisting of a high performance DSP chip and chargeable lithium batteries is adopted, and the measurement results are saved in the internal FLASH storage, thus meeting the operating requirements of farming investigations of overwhelming majority and ensuring higher measurement accuracy.

The invention discloses an interferometry-based optical fiber Verdet constant measuring system. The system comprises an ASE (amplified spontaneous emission) light source, a single-mode optical fiber coupler, a Y-waveguide integrated optical modulator, 1 / 4 wave plates, Faraday rotator mirrors, a solenoid, a sine alternating-current driving circuit, matching fluid, a probe, an information processing module, a computer and measured optical fibers. The ASE light source, the single-mode optical fiber coupler, the Y-waveguide integrated optical modulator, the measured optical fibers and the Faraday rotator mirrors are connected through optical fibers in sequence. Each 1 / 4 wave plate is arranged between the Y-waveguide integrated optical modulator and the corresponding measured optical fiber. A signal processing portion comprises a feedback servo circuit, an FPGA (field programmable gate array) module and a phase modulation driving circuit. The system is of an all-optical-fiber structure and simple and convenient to set up; by the aid of the Faraday rotator mirrors, influences of linear birefringence of the optical fibers on measurement can be eliminated, and measurement accuracy is improved; and Verdet constants of various optical fibers can be measured by the system.

The invention discloses a motor rotor position sensor and a method which precisely measures the rotor position by the sensor; the rotor position sensor comprises an objective disc which is arranged on the objective rotor, provided with a sine / cosine curved shape and made of conductive, an inductive element which is fixed in the shell of a motor, corresponding to the objective disc and provided with a plane winding, and an ASIC circuit which is connected with the induction circuit; the method completes the operation of precisely measuring the rotor position by using a DSP to process the signal induced by the rotor position sensor; the sensor meets the automobile standard, is not affected by the magnetic field of the motor stator winding, and has the advantages of high performance and low cost. The method used for precisely measuring the position and rotation speed of the rotor of the motor can be uniformly completed by the DSP device; therefore, the sensor and the method can precisely measure the position and speed of the motor rotor; furthermore, the device has simple structure and low cost.

The invention discloses a real-time absolute ranging method and system based on single-chamber dual-femtosecond optical comb cross-correlation analysis. The method comprises steps: S1, two simultaneously-outputted femtosecond optical combs with different repetition frequencies are generated, the two different repetition frequencies are fr1 and fr2, and the repetition frequencies are locked to an atomic clock by frequency stabilization control; S2, after the beam of the two femtosecond optical combs passes through an interferometer optical path module, the orthogonal polarization components ofoptical comb pulse return light (reference light and measurement light) and local optical comb pulses are measured, and after combination, two groups of femtosecond laser pulse pairs with mutually-perpendicular polarization directions are generated; S3, two-path optical balance cross-correlation signals for reference and measurement are generated, and the signales can be generated by a femtosecondpulse cross-correlation analysis unit in the embodiment of the invention; and S4, the balance cross-correlation signals are subjected to high-speed digital signal analysis processing to obtain a ranging result. The system is the device used for executing the above method. The method and the system disclosed in the invention have the advantages of large ranging range, fast updating speed, high measuring precision and simple operation and the like.

The invention discloses an ultrasonic flow rate measuring method and device. In the traditional flow velocity measurement, a measured result needs to be subjected to temperature compensation. In the method disclosed by the invention, the flow rate can be calculated by measuring down-flow propagation time t1, counter-flow propagation time t2 and electronic circuit delay time tr of an ultrasonic wave in fluid. The device disclosed by the invention comprises a first energy transducer, a second energy transducer, a first analog switch, a second analog switch, a third analog switch, a first signal conditioning circuit, a second signal conditioning circuit, an ultrasonic wave transmission timing circuit and a single-chip microcomputer. By means of the invention, the influence of fluid temperature to flow rate measurement is eliminated, the precision of flow rate measurement is improved, and the cost of the device is saved.

The invention discloses a rotating shaft torque measurement method and a system based on wireless technology. The method comprises the following steps: 1) collecting a voltage analog signal; 2) performing amplification, filtering and analog-to-digital conversion on the voltage analog signal to obtain a voltage digital signal; 3) transmitting the voltage digital signal to an upper computer througha Bluetooth data transmitting module, and obtaining a torque value of the rotating shaft after being processed by the upper computer; 4) the required power is supplied by wireless power supply. The system comprises a strain gauge torque sensor, an integrated circuit board, an upper computer and a wireless power supply device. The wireless power supply device comprises a power receiving component and a power transmitting component; the upper computer is provided with a Bluetooth data receiving module; the integrated circuit board is integrally provided with a power module, a strain signal processing module, a data processing module, and a Bluetooth data transmitting module. According to the rotating shaft torque measurement method and the system based on wireless technology, the torque measurement accuracy of the rotating shaft is improved by the combined application of wireless power supply and Bluetooth data transmission.

The invention discloses a spectrophotometer for the chromaticity detection of laser paper and belongs to the technical field of optical detection instruments. In the spectrophotometer disclosed by the invention, the spherical surface of a diffused lighting integrating sphere is provided with a sample reflecting hole, an incident hole of the diffused lighting integrating sphere and an exit hole of the diffused lighting integrating sphere; the spherical surface of a diffused accepting integrating sphere is provided with an incident hole of the diffused accepting integrating sphere and an exit hole of the diffused accepting integrating sphere; the exit hole of the diffused lighting integrating sphere and the incident hole of the diffused accepting integrating sphere are same in diameter and are in butt joint with each other; and the sample reflecting hole is connected with a laser paper sample, a flat-filed concave grating is arranged in front of a light path of the exit hole of the diffused accepting integrating sphere, a photoelectric converter, namely a linear array CCD (charge coupled device) is arranged in front of a dispersive light path of the flat-filed concave grating, and the electrical signal output end of the linear array CCD is connected with a signal processing system. The spectrophotometer disclosed by the invention is reasonable in design, simple in structure, and convenient in use, and can be used for correctly measuring the surface spectral reflectances and colorimetric values of all types of laser paper.

In the technological scheme of the present invention, the measuring method includes the following steps: irradiating the measured body with wideband light beam, leading the transmitted light with a light splitting device to a photosensitive sensor, and transmitting the signal of the photosensitive sensor to a computer for processing. The present invention has accurate measurement, can elimiante the effect of differences in individual, pulse amplitude, blood turgor, etc. to measurement, and can measure several blood components.

The invention belongs to the technical field of geometric size measurement, and discloses a single-lens laser trigonometry thickness measuring instrument. The measuring instrument comprises laser devices, an aperture diaphragm, planar glass, a combined lens, an image detector, an image processor and certain auxiliary fine adjusting devices. When the measuring instrument works, the upper and lower laser devices aligned coaxially emit two beams of collimated rays, the rays are focused to the surface of a measured object by the lens in front of the laser devices, the diffuse reflectance rays on the surface of the measured object pass through the aperture diaphragm and the planar glass and then are gathered to the image detector through the combined imaging lens, image data are transmitted to the image processor for image processing, the actual thickness of the measured object is calculated according to the distance between two light spots, and the measurement thickness is finally displayed. By inheriting the advantages of a laser triangle thickness measuring method, improving the structure of a light path and optimizing the design, the problems that upper and lower independent measuring systems are difficult to synchronize and the precision is difficult to ensure because a double-path laser trigonometry thickness measuring instrument is affected by vibration of the measured object are well solved.

The invention discloses a method for automatically obtaining the geometric parameters of a stone based on machine vision, and the method comprises the following steps: (1), building a stone image collection platform; (2), collecting a calibration board image and a stone image, and selecting effective areas of the images; (3), carrying out the tilt correction, distortion correction and size calibration; (4), generating gray scale images of the effective areas according to different backgrounds and corresponding conversion formulas; (5), generating binary images of the effective areas; (6), detecting the boundary contour of the stone, and calculating the actual area and perimeter of the stone; (7), calculating parameters corresponding to different filling and cutting schemes according to the boundary contour of the stone. The method can obtain the geometric parameter information of the stone quickly and accurately, is simple and quick in operation, is high in precision of the measurement result, is low in implementation cost, and is strong in anti-interference capability.

The invention relates to a signal processing method of an automatic zero-point electromagnetic flow meter and a system thereof. Working periods with excitation current I=0 are incessantly inserted during a working process of a magnetic field B generated by the excitation current I of the electromagnetic flow meter. By means of the characteristic that inductive electric potential E equals zero on the condition that I equals zero and B equals zero. Dynamic detection is carried out at this time with an output signal U of a signal amplifying unit as a signal zero-point value Z so as to utilize data deprived of a dynamic zero-point value Z to accurately estimate an actual flow velocity V. Obviously, influence on measurement of the flow velocity V caused by zero-point change is eliminated, and automatic calibration of an zero point is achieved so that an electromagnetic flow meter newly arranged on a technological pipeline can be directly put in operation without firstly adjusting the zero point and the like on the condition that the flow V equals zero, thereby greatly improving utilization performance of the electromagnetic flow meter. Meanwhile, change of symmetrical performance of the inductive electric potential of the sensor can be measured according to change of the signal zero point value Z so as to diagnose change of electrode pollution, insulation performance and the like of the sensor.

The invention discloses an alignment instrument measurement and adjustment method for a generator coupling shaft system. The method is characterized in that the method comprises the following steps: 1, fixing a first displacement sensor on one of coupled wheels of a generator in a direction vertical to the axis to measure the circumference offset amounts of the other one of the coupled wheels, and fixing a second displacement sensor on the one of the coupled wheels of the generator in a direction parallel to the axis to measure the transverse plane opening displacements of the other one of the wheels; 2, measuring the circumference offset amounts and the end transverse plane opening displacements, calculating to obtain a horizontal offset amount, a vertical offset amount, an upper transverse plane opening amount, a lower transverse plane opening amount, a left transverse plane opening amount and a right transverse plane opening amount; and 3, calculating according to the horizontal offset amount, the vertical offset amount, and the upper transverse plane opening amount, the lower transverse plane opening amount, the left transverse plane opening amount and the right transverse plane opening amount to obtain pad adjustment amounts, and adjusting pads according to the pad adjustment amounts. The method has the advantages of fastness and convenience in the whole alignment process, and high precision.

A thermal flowmeter comprises a thermal flow sensor having first and second temperature detection elements (Ru, Rd) disposed in the direction of flow of fluid with a heater element (Rh) disposed therebetween, a first temperature sensor (12a) for detecting the temperature of the fluid flowing in a pipe (10), a second temperature sensor (12b, 12c) for detecting the pipe temperature, wherein the flow rate of the fluid is measured from the difference in detection output between the first and second temperature detection elements, while the amount of flow rate correction is found from a temperature difference correction table (24) according to the difference between the pipe temperature and the fluid temperature, the amount of flow rate correction being used to correct the measured fluid flow rate, which correction is capable of eliminating the thermal effect on flow rate measurement from the external environment so as to improve the measurement accuracy.