73results about How to "Does not affect measurement" patented technology

The invention discloses a weight loading ring-piece type corrosive wear tester, consisting of a stand, a weight loading system, a friction force measuring system, a transmission system and a crucible resistance furnace system. The weight loading system is internally provided with a lifting rotary plate; during loading, the weight tray is located in the low order; during unloading, the lifting rotary plate is rotated; the weight tray is risen to a high-order for bearing a weight; one end of a first wire rope in the weight loading system is horizontally led out and then wound on a pinion of a force-increasing roller; one end of a second wire rope is fixed and then wound on a bull wheel of the force-increasing roller; and the weight is suspended on the sagging end. In the invention, a ringlike sample and a block-like sample are used as the friction pair, liquid metal is used as the corrosive medium, the behavior of the solid friction pair for bearing corrosion and wear at the same time in the liquid metal can be simulated, the load, temperature, rotating speed and liquid metal supply test parameters can be changed, the friction force can be measured and high load-applied accuracy and high measuring precision are ensured.

The invention provides a thin-layer flow electrolytic cell applicable to electrochemical in-situ Raman spectrum detection. The thin-layer flow electrolytic cell employs the design of a semispherical window; and a solution flows in a right solution channel, a solution chamber and a left solution channel, thereby forming the flow electrolytic cell. Through introduction of the flowing function, the thickness of a solution layer between a working electrode and the window can be substantially reduced, so collection efficiency and detection sensitivity of Raman scattered light are greatly improved while electrochemical measurement is not influenced. Meanwhile, the design of the semispherical window can eliminate the refraction effect of an interface of air and the quartz window, reduce difference between the focus of a laser optical path and the focus of an optical imaging optical path and decreases divergence angles of light, so acquisition efficiency and detection sensitivity of Raman spectra are improved. The thin-layer flow electrolytic cell can monitor dynamic changes of surface adsorbed species in the process of an electrochemical reaction in situ in a wide temperature range and obtains inherent information of surface adsorbed substances related to parameters of reaction kinetics.

A vehicle wheel service apparatus, in particular a wheel balancer or a tyre changer, comprising a load means (26, 126) for applying a predetermined load onto a peripheral surface of a wheel / tyre assembly (14), a sensor device (30) arranged to determine forces acting between the peripheral surface of the wheel / tyre assembly (14) and the load means (26, 126), wherein the forces comprise at least a first force acting in a radial direction of the wheel / tyre assembly (14) and a second force acting in a circumferential direction of the wheel / tyre assembly (14), and an evaluation device arranged to determine a rolling resistance coefficient of the tyre (10) on the basis of the first and second forces.

The invention discloses a flexible cell management system and belongs to the cell management and energy storage field. The flexible cell management system can realize flexible measurement, protection and management on cells of the cell groups, has low requirements for external voltages and can be directly connected with AC. The flexible cell management system comprises multiple cell management units connected in serial and in parallel, wherein each cell management unit comprises one or two cells and four or six switches, and can realize external port positive connection, reverse connection and bypass functions, and the switches can any type of diodes, triodes, relays, thyristors, silicon controlled rectifiers, MOS tubes and IGBTs and can also be combination of all the types above to form a bi-directional switch module or device. The flexible cell management system can be composed of multiple cell management units in series, in parallel, in series and then in parallel, in parallel and then in series, or in hybrid connection mode. The flexible cell management system has low requirements for external charging and discharging voltages and can even realize external AC charging and discharging, the flexible cell management system further improves reliability of the cell groups, and internal resistance can be easily and accurately measured.

The invention provides a near-field strong interference source inhibition method in an underwater far-field target passive positioning process. The method comprises the following steps of: before sonar equipment detects a far-field target, utilizing a near-field sound figure scanning method to extract the number N and position information of interference sources in a near-field area of the sonar equipment; building a model in which a near-field strong interference source exists when an underwater far-field target is detected, and calculating to obtain steering vectors of position coordinates on which i interference source is located; determining forms of a wave beam null width weight and an azimuth spectrum; judging whether a signal received by a receptive array belongs to a wideband signal or not; dividing the received wideband signal into a plurality of narrow-band signals on a frequency domain; and finally, synthesizing outputs of all frequency bands to obtain an estimation result of the wideband signal. According to the near-field strong interference source inhibition method in the underwater far-field target passive positioning process, local interference is regarded as a near field, a wave beam directive null point focused to a point is formed aiming at the position coordinates on which the near field is located, the concrete forms of the wave beam null width weight and the azimuth spectrum are provided, dead zone influence brought by the prior wave beam null width method is overcome, and meanwhile, a true target is regarded as a far field to be measured.

The invention discloses a flatness detection device based on civil engineering and relates to the technical field of civil engineering. A connecting box is fixedly connected to one side of a box body.Vertical frames are fixedly connected between the top and the bottom of the inner wall of the box body. The two vertical frames are arranged and located on the left side and the right side of the inner wall of the box body. A first electric telescopic piece is fixedly connected to the top and the bottom of one side of the inner wall of each vertical frame. By the adoption of the flatness detection device based on civil engineering, the device can be effectively triggered and stopped through a touch switch when an unstable condition happens, and stability is guaranteed; through mutual cooperation, whether flatness is reached or not can be known in time, observation is conducted, the accuracy in the measurement process is guaranteed, and work efficiency is improved; and the angles of pressswitch pieces correspond to those of squeezing blocks, the overall balance of the device can be guaranteed in the uphill and downhill processes, an inclination state is avoided, and the stability in the measurement process is guaranteed.

The invention provides a right angle calibration block layout method, a coordinate calibration method and a coordinate adjusting method for a gear measurement center. The layout method is to set the right angle calibration block layout fixed on the non-rotary table at a position other than the measurement stroke, and then use the reference template and the right angle calibration block to establish an indirect gear measurement center coordinate calibration method. The coordinate calibration method comprises steps of 1) preliminarily determining the position coordinates of the right angle calibration block in a rotation center; 2) determining the position coordinates of a probe in the rotation center; and 3) accurately determining the position coordinates of the right angle calibration block in the rotation center. The invention solves the problems that the coordinate calibration program in the traditional gear measuring system is complicated, the precision is low, the calculation method is complicated and the requirement for the positioning position of the probe is high; position coordinates of the tangential X axis, the radial Y axis and the vertical Z axis are precisely determined when the right angle calibration block is at the zero point relative to the rotation center; and the position coordinates of the center of sphere of the probe head relative to the measurement system are determined.

The invention discloses an aspheric myopia eyeglass, comprising a back surface and a front surface. Curved surfaces of the back surface and the front surface are all aspheric even number aspheric refracting surfaces. The even number aspheric refracting surface is determined by a function as below; optimized variables are increased by times, so as to reach higher imaging quality and larger thinning amount. In addition, the even number aspheric refracting surface guarantees holosymmetry of the eyeglass and is beneficial for processing and manufacture; detection is same as a general spherical eyeglass, and measurement of degrees of eyeglass will not be influnced. The front surface and the back surface employ completely opposite aspheric design, so that various design errors and processing errors can compensate mutually. The eyeglass has excellent stability, and will not cause uncomfortableness to first time wearer due to various errors. Therefore, the aspheric myopia eyeglass has advantages of thin thickness, light weight, good imaging quality and facility for processing, etc.

The invention discloses a fiber grating stress sensor which is not sensitive to temperature. A sensing head structure body (40), a first phosphor copper rod (32) and a fourth phosphor copper rod (60) are vertically fixed on the bottom part of a sealing body. The upper end surface of the sensing head structure body is contacted with the lower surface of a sliding cover (21). A second phosphor copper rod (42) is vertically stuck on the sensing head structure body (40). A third phosphor copper rod (52) is respectively connected with the fourth phosphor copper rod (60) and the second phosphor copper rod (42) by connecting pieces (50), (41). A measuring fiber raster (51) and a reference fiber grating (31) are respectively stuck on the third phosphor copper rod (52) and the first phosphor copper rod (32). The measuring fiber grating is connected with an optical power meter (90) through a right circulator. The reference fiber grating is connected with a broadband light source (80) through a left circulator. The sensor is not sensitive to temperature and is especially suitable for the running control of high-speed railway trains and the real-time tracing on trains.

The invention discloses a low-frequency pressure pulsation suppression method for a 3 / 4 opening test section of a wind tunnel. The wind tunnel is the 3 / 4 opening test section, the test section sequentially comprises a jet nozzle, a test section floor and a jet collector from one end to the other end, wherein a wall plate for inhibiting vortex development is arranged in an excitation source propagation path and a disturbance feedback loop at the downstream of the test section. The device is simple in structure, does not need to damage a wind tunnel body structure, is installed at the downstreamof a 3 / 4 opening test section, does not affect measurement of far-field noise after low-noise design and noise elimination measures are added, directly acts on a low-frequency pressure pulsation generation source, and can play a good role in restraining low-frequency pressure pulsation of different propagation paths.

The invention discloses a fibre grating stress sensing train positioning and real-time tracking system which is insensitive to temperature. The system of the invention is characterized in that a plurality of fibre grating stress sensors (A211...A21n)...(A211...A21n) with different central wavelengths are embedded just below one steel rail of each line of the railway with the interval of 100-500 meters. A broadband light source (A10) is connected with a fast optical switch (A20) and a first fibre grating stress sensor (A211...a2m1); a final fibre grating stress sensor (A21n...A2mn) is connected with an optical amplifier (A30), a wavelength-division element (A41), a high-speed optical switch (A42), an O / E converter (A43), a digital signal processing module (A44), a host computer (A45), as well as a server (A47) and a large screen (A46) which memorize three-dimensional electronic maps. The fibre grating stress sensing train positioning and real-time tracking system is suitable for the positioning and real-time tracking of the high-speed railway trains.

The invention relates to a method and device for measuring the mass of a solid in a solid and liquid mixture. The method comprises the following steps that a) the type of the solid in the solid and liquid mixture is determined, and the density Psolid of the solid is obtained by a table look-up or experiment method; b) the Volume Vmixutre and the mass Mmixture when the volume of the solid and liquid mixture equals Vm are measured; and c) according to that the volume of the solid and liquid mixture equals the sum of the volume of the solid and the volume of the liquid and that the mass of the of the solid and liquid mixture equals the sum of the mass of the solid and the mass of the liquid, an equation set is obtained, and values in the steps a) and b) are substituted into the equation set to obtain the Msolid. The method is simple and practical, realization approaches are diversified, both online measurement and static measurement can be realized, and the measuring precision is easy to control.

The invention relates to a thermal imager online calibration method under a space simulation environment. A space simulation container is arranged, a black body serving as a calibration device is arranged between the inner wall of the space simulation container and an interlayer of a heat sink and / or in the space simulation container, a test objective is arranged in the space simulation container,a thermal imager is arranged outside or inside the space simulation container, the relative positions of the thermal imager and the black body are adjustable, and by collecting an image of the blackbody, the thermal imager is calibrated online in real time. Accordingly, the calibration device can be flexibly moved in and out in a test, the purpose that in the same test ground, calibration on thethermal imager under the inside and outside circumferences and measurement on the objective can be achieved, and the measuring error is small.

The invention relates to a sensor element (10) having at least one piezoelectric transducer (11), said piezoelectric transducer (11) being coupled to at least one memristor (20). The invention further relates to a sensor having an array of a plurality of pixels, at least one of the pixels comprising a sensor element (10).

The invention discloses a fiber asphalt mortar blending uniformity self-checking device and method. The device comprises a blending unit, a testing unit and a control unit connected with the blending unit and the testing unit, wherein the blending unit comprises a blending reaction pot arranged on a base, a sealing plate is arranged above the blending reaction pot, a blender is arranged at the bottom of the sealing plate, and a plurality of stirring rods are arranged on the blender; an electric heater is arranged on the blending reaction pot; the testing unit comprises viscosity sensors and temperature sensors which are arranged on the stirring rods; the control unit comprises a PLD (programmable logic device) controller connected with the electric heater and the viscosity sensors. The dispersion effect of fibers in fiber asphalt mortar is really reflected by comparing viscosity information of all the test points, capturing of the fiber distribution effect is realized according to mortar viscosity, the blank for detection of the fiber asphalt mortar blending effect in China is filled up, and the device and the method have great promotion value in production.

The invention relates to a current measurement technology of electrotechnics and specifically to a DC heavy-current measuring device and measuring method. The device comprises a four-column iron core,an excitation winding, a compensating winding, an excitation signal producing circuit, a driver, a signal conditioning circuit, a power amplifier and a standard resistor. The measuring method comprises the steps of converting electrical current flow to magnetic flux for detection; realizing magnetic circuit splitting through cooperation of a special iron core structure and the bridge-type connected excitation winding; and after performing signal processing on the middle-point voltage difference of the bridge-type connected excitation winding, controlling the current of the compensating winding to enable the magnetic flux to recover balance. Problems such that a zero-magnetic-flux current sensor feedback detection circuit is complex, the compensating current has excitation signal ripple waves, and the transient current and harmonic current are difficult to detect.

The invention discloses a high-pressure spray characteristic testing system for use at a high temperature and under a high back pressure. The testing system consists of a constant volume combustion chamber, a heating system, an ignition and fuel injection system, a synchronous control system, a transient high-temperature and high-pressure measurement system and a high-speed camera system. Before testing, the constant volume combustion chamber is heated to a target temperature by the heating system, fuel and air are mixed, and the mixed gas pre-burns to establish a high-temperature and high-back-pressure condition. In a high-temperature and high-back-pressure environment, a fuel injection system injects diesel into the constant volume combustion chamber, temperature and pressure sensors record relevant data, and the high-speed camera system shoots a spray form, thereby completely recording spray characteristic data. The testing system provided by the invention can detect the spray characteristics in a real engine environment. Fuel is injected into the constant volume combustion chamber firstly, and burns in the constant volume combustion chamber to increase the temperature and pressure in the constant volume combustion chamber. The testing environment is a high-temperature and high-back-pressure environment, which is consistent with an actual engine environment.

The invention discloses an aspheric myopia eyeglass, comprising a back surface and a front surface. Curved surfaces of the back surface and the front surface are all aspheric even number aspheric refracting surfaces. The even number aspheric refracting surface is determined by a function as below; optimized variables are increased by times, so as to reach higher imaging quality and larger thinning amount. In addition, the even number aspheric refracting surface guarantees holosymmetry of the eyeglass and is beneficial for processing and manufacture; detection is same as a general spherical eyeglass, and measurement of degrees of eyeglass will not be influnced. The front surface and the back surface employ completely opposite aspheric design, so that various design errors and processing errors can compensate mutually. The eyeglass has excellent stability, and will not cause uncomfortableness to first time wearer due to various errors. Therefore, the aspheric myopia eyeglass has advantages of thin thickness, light weight, good imaging quality and facility for processing, etc.

The invention discloses a weight loading ring-piece type corrosive wear tester, consisting of a stand, a weight loading system, a friction force measuring system, a transmission system and a crucible resistance furnace system. The weight loading system is internally provided with a lifting rotary plate; during loading, the weight tray is located in the low order; during unloading, the lifting rotary plate is rotated; the weight tray is risen to a high-order for bearing a weight; one end of a first wire rope in the weight loading system is horizontally led out and then wound on a pinion of a force-increasing roller; one end of a second wire rope is fixed and then wound on a bull wheel of the force-increasing roller; and the weight is suspended on the sagging end. In the invention, a ringlike sample and a block-like sample are used as the friction pair, liquid metal is used as the corrosive medium, the behavior of the solid friction pair for bearing corrosion and wear at the same time in the liquid metal can be simulated, the load, temperature, rotating speed and liquid metal supply test parameters can be changed, the friction force can be measured and high load-applied accuracy andhigh measuring precision are ensured.

A supertoric astigmatic glass piece is characterized by that with light shaft as the shaft Z the astigmatic surface is got by the basic curve rotating round a straight line parallel to shaft Y and crossed with shaft Z. The said basic curve is the curve crossed by the astigmatic surface and Y-Z panel, expressed in a formulary, in which c expresses the curvature of curve top, a1, a2, a3, a4, a5 are factors of curve high-order term, k is the quadratic curve constant. This invention esses up uneven thickness of the edge of glass pieces to be thinner, and increases quality of image, not influencing the measurement to the basic degrees and astigmatic degrees of glass blocks.

The invention relates to an oil well liquid level measuring method and device for oil well liquid level measurement. The method includes the following steps that a, a ground frequency converter outputs frequency f1, the rotation speed n of a submersible screw pump is obtained through calculation, n is substituted into the formula of T3=91.3delta0-n0.45+46.5, and the torque T3(f1) of the submersible screw pump is obtained through calculation; b, the total power supply output torque T1(f1) is measured through a ground torque tester; c, the torque T2(f1) of lifting liquid is calculated through the formula of T2(f1)=T1(f1)-T3(f1); d, the height h(f1) of the lifting liquid is calculated through the formula in the specification. According to the measuring device, a power supply is connected with the submersible screw pump through a cable by means of the torque tester and the frequency converter. The measurement method and device do not depend on echo location and improve measurement precision.

The invention relates to a tunnel engineering monitoring measurement point protecting device and a mounting method. The device comprises a protective cover, support nuts, fixing supports, a measurement point, a center shaft fixing nut and LED lights. Before embedding of the measurement point, the center shaft fixing nut sleeves a measurement point connection rod, and then the measurement point isput in a preserved drill hole and fixed in a tunnel vault or a side wall; after fixing, the measurement point is exposed, and a reflective plate is adhered to the measurement point; the protective cover is connected with the measurement point through the fixing supports and fixed to the side wall through the center shaft fixing nut. Due to annular encircling of the measurement point, the measurement point can be effectively protected from being damaged by blasting flyrock or tunnel construction machinery while measurement requirements of the measurement point can be well met. In addition, thetunnel engineering monitoring measurement point protecting device has advantages of simple structure, simplicity in operation and the like.

The invention relates to a specimen disc positioning device of a total reflection X-ray fluorescence spectrophotometer, which comprises a specimen disc frame located under a detector, the bottom surface of the specimen disc frame can be horizontally drawn, a specimen disc is horizontally arranged on the bottom surface of the specimen disc frame; a compressing device is arranged under the bottom surface of the specimen disc frame, and horizontal positioning devices are arranged on borders at two sides of the specimen disc frame. The problems of specimen loading and specimen positioning of a total reflection X-ray luminoscope of a horizontal specimen-loading system is solved by the specimen disc positioning device of the total reflection X-ray fluorescence spectrophotometer, which is provided by the invention. The positioning device does not influence the incident light and the emergent light, the structure is simple in operation, and the position is fixed.

The invention relates to a pile foundation detection system using a self-balancing method. The pile foundation detection system comprises an upper steel bar cage, a lower steel bar cage and a load box; the load box comprises an upper bottom plate and a lower bottom plate; the periphery of the lower side of the upper bottom plate is fixedly connected with a hoarding which can abut against the upper side of the lower bottom plate under normal conditions; the peripheral surfaces of the ends where the upper steel bar cage and the lower steel bar cage close to each other are fixedly connected with steel rings; a steel sleeve is arranged on the outer side of the load box, the lower end of the steel sleeve is fixedly connected to the steel ring of the lower steel bar cage, and the upper end of the steel sleeve is slidably connected to the steel sleeve of the upper steel bar cage; a filling cavity is formed between the steel sleeve and the two steel rings as well as the steel sleeve and the hoarding; and the upper side of the steel sleeve is further fixedly connected with a plurality of filling tubes which can extend out of the upper end of the upper steel bar cage and communicate with the filling cavity. The pile foundation detection system using the self-balancing method has the effects that broken piles after measurement can be effectively bonded, so that the upper pile part and the lower pile pat can be integrated into a whole so as to improve the bearing capacity of the broken piles, and the subsequent measurement and use are convenient.

The invention relates to the field of gene sequencing, and discloses a gene sequencing reaction device. The gene sequencing reaction device comprises a gene sequencing reaction small chamber and a temperature measuring device, wherein the temperature measuring device comprises a temperature measuring probe; the gene sequencing reaction small chamber comprises a first substrate and a second substrate, a first groove is arranged in the first substrate, and after the first substrate attaches to the second substrate, the first groove is a reaction channel; a reagent inlet and a reagent outlet arearranged in the second substrate; the reaction channel is composed of a reaction part and a bending part, the bending part is connected with and communicates with the reaction part, and an included angle is formed between the bending part and the reaction part; a bulge is arranged on the outer surface of the second substrate, and the bulge is arranged at the position corresponding to the joint ofthe reaction part and the bending part; a temperature measuring hole is formed in the bulge, and the temperature measuring hole is used for the temperature measuring probe. The gene sequencing reaction device has the beneficial effects that the distance between a lead connected to the temperature measuring probe and a reagent inlet pipeline is increased, so that the interferences between the leadand the reagent inlet pipeline are avoided.

The invention discloses a direct voltage tester and a method for testing direct voltage. The direct voltage tester comprises a high-resolution analog-digital converter, a high-precision regulated power supply and a serial port output circuit. The high-precision regulated power supply and the serial port output circuit are respectively connected with the high-resolution analog-digital converter. The high-resolution analog-digital converter compares reference voltage of the high-precision regulated power supply with the received input voltage to obtain comparison data, and then converts the comparison data to digital signals and outputs the digital signals through the serial port output circuit. Because resolution ratio is very high and cost is very low, the selected analog-digital converter has very low rate of conversion, but measurement of stable direct voltage is not affected. Serial port output of digital signals can enable the voltage tester to be integrated with other systems conveniently. With the help of a single chip microcomputer or a master control computer, an input voltage value can be quickly obtained, utilized and calculated. Therefore, when the direct voltage tester is used, testing cost of direct voltage is remarkably reduced, structure is simple and precision is high.

The invention relates to the technical field of water quality acquisition, and particularly relates to a water environment parameter acquisition device and method. The device comprises a tank body, afiltering assemblies, a pH temperature sensor, a dissolved oxygen sensor, a turbidity sensor, a conductivity sensor and a cleaning and air blowing assembly, wherein the tank body is placed in an inclined mode, the liquid inlet end of the tank body is provided with a water inlet interface, the liquid outlet end of the tank body is connected with an overflow interface, the upper part of the tank body is provided with four sensor interfaces, the pH temperature sensor, the dissolved oxygen sensor, the turbidity sensor and the conductivity sensor are sequentially and respectively arranged at the four sensor interfaces of the tank body from the feeding end to the discharging end, and the middle parts of the four sensor interfaces are provided with filtering interfaces; the lower part of the tankbody is provided with four air blowing interfaces corresponding to the lower parts of the four sensor interfaces; the filtering assemblies are arranged on the filtering interfaces of the tank body; the cleaning and air blowing assembly comprises four cleaning and air blowing joints; and each cleaning air blowing joint is matched with a measuring probe to realize self-cleaning. The device has theadvantage that the self-cleaning and maintenance-free effects can be realized conveniently.

The invention discloses a mobile phone accessory and a mobile phone APP (application) capable of testing wind power and a wind direction. The mobile phone accessory is a device which is used for testing the wind power and the wind direction through a certain swing direction and swing angle generated by a capacitance pen, which is hung on a fixed support and can swing with the wind, under the action of the wind power, recording the wind power and the wind direction by an induction location of a mobile phone screen, and reading and displaying a wind power value and a wind direction value further by the mobile phone APP. The mobile phone accessory is simple in structure, small in size, convenient to carry, simple in operation and low in cost, and is suitable for real-time and site-specific application.

The invention provides a sensor intermittent type automatic brushing and cleaning device. The sensor intermittent type automatic brushing and cleaning device comprises a fixing frame, a cleaning wheel, an intermittent linkage device and a driving device, wherein the fixing frame, the cleaning wheel, the intermittent linkage device and the driving device are fixedly installed together with the sensor. The sensor intermittent type automatic brushing and cleaning device can perform intermittent type brushing and cleaning on the sensor and does not need to be in contact with the sensor at all times, the measurement sensitivity of the sensor is improved, and the probability of damage or breakdown to the sensor during cleaning is reduced. When the dirt does not form a stable state, brushing andcleaning are carried out in time without affecting the real-time measurement of the sensor, and the defect of inaccurate trend of historical data due to the fact cleaning is started only after the sensitivity of the sensor decreases is overcome, and the sensor intermittent type automatic brushing and cleaning device is more advantageous than regular, centralized and high-intensity automatic brushing and cleaning in the prior art.

The invention relates to a multi-sound-path ultrasonic flow measurement pipe section body and belongs to the technical field of ultrasonic flow measurement. According to the technical scheme, sensor mounting bases are arranged on a pipe section body, sensor mounting holes are formed in the sensor mounting bases, ultrasonic sensors are arranged in the sensor mounting holes, a plurality of upstreamside ultrasonic sensors and a plurality of downstream side ultrasonic sensors are matched with each other, ultrasonic waves are transmitted and received to form a plurality of ultrasonic measurement sound paths, a signal of each ultrasonic measurement sound path is processed, finally, a flow value in a pipe section body is obtained, and the number of the formed ultrasonic measurement sound paths is larger than or equal to the sum of the number of the ultrasonic sensors on the pipe section body. According to the invention, the number of the ultrasonic sensors is greatly reduced, and the improvement of the measurement precision is facilitated.