52results about How to "Low measurement limit" patented technology

The invention discloses a measuring device and a measuring method of light scattering particles. The measuring device successively comprises a divergent beam module, a measurement zone, a receiving lens, a multielement photodetector, a transmission light detector, a signal processing circuit, and an analog-to-digital converter. The method comprises the following steps that: particles in the measurement zone are illuminated by the divergent beam, the scattered light and transmission light are collected by the receiving lens simultaneously, the scattered light is projected on each detection unit of the multielement photodetector to obtain a scattered light distribution signal, the un-scattered part of the incident light is received by the transmission light detector to obtain a transmissionlight signal, the scattered light distribution signal and transmission light signal are amplified, collected and converted by the signal processing circuit and the analog-to-digital converter, and particle size distribution and concentration information are calculated according to the scattered light distribution signal and transmission light signal. According to the invention, the problem of signal interference caused by close distance between the measurement zone and the detector is solved, the lower limit of the particle measurement is lowered, and the invention can be applied in a plurality of areas of particle measurement.

The invention discloses a tracer flow polymer injection profile well logging instrument, a tracer, a tracer makeup device and a well logging method. The well logging instrument comprises a remote-sensing nipple equipped with a collar locator CCL, a tracer sprayer equipped with a continuously rotating motor, and a gamma-ray probe equipped with a near probe and a far probe. The tracer makeup device comprises a control box and a makeup box. The makeup box, which is equipped with a lead glass screen and a lead plate, is arranged on the control box. The bottom of the makeup box is equipped with a guide rail and a protection plate. A stirrer and a funnel are arranged above the guide rail. The stirrer is connected with a weight dropper. 4.5 to 3.5 weight shares of solid polymer, 4.5 to 3.5 weight shares of guar gum, and 2.5 to 1.5 weight shares of amylum are mixed with a tracer suspension to make a liquid with the concentration of 2000mg per litter, and then the liquid together with the 0.5mCi 131Ba micro-spherical tracer to make a suspension. The tracer flow well logging method and the isotope tracer water-injection profile well logging method are used for the well logging. The tracer suspension is first evenly sprayed continuously and then is sprayed in a spotting way. The tracer suspension of the invention is even, and is provided with a low lower limit and a high precision. Moreover, the well logging instrument of the invention is low in the cost.

The invention relates to a wavelength modulation spectrum technology-based denitrified ammonia escape rate measurement device and method, belonging to the technical field of tunable diode laser absorption spectroscopy. The method is characterized in that laser is split through an optical beam splitter on the basis of quadruple sub-harmonic in the wavelength modulation spectrum technology, a part of laser permeates a high-concentration reference cell to be used for locking a central wavelength and monitoring the zero point of an instrument constantly, and the other part of laser permeates a smoke measurement cavity to be used for obtaining the concentration of an ammonia gas. In an in-situ sampling mode, a sampling rod and the measurement cavity are both arranged in a flue of a denitrified air preheater. The method has the characteristics that with adoption of a low-pressure measurement method, the pressure of the measurement cavity is kept at 0.1atm, a strong absorption spectrum line can be selected and the interference from other gas spectrum lines can be avoided, the sensitivity of the instrument can be improved, and the lower limit of measurement can be lowered. Through the method, a series of problems, caused during application of an existing ammonia escape rate instrument, such as the incapability of laser to permeate dust with high concentration, the deflection of laser resulted from mechanical deformation of a flue wall, the incapability of marking, and blocking of a filtering permeation probe, can be solved.

The invention discloses a gas concentration measuring method based on spectral absorptivity second harmonics feature extraction. The method disclosed by the invention realizes calculation of integralabsorbance by virtue of harmonic characteristics by building a spectral absorptivity second harmonics peak height-peak width characteristic relation applicable to any modulation coefficient and considering a Voith line type, thus gas parameter information is obtained; meanwhile, in an implementation process of the method, a logarithm processing technology is adopted, influence of residual amplitude modulation on harmonic signal distortion is directly eliminated, and measurement accuracy is improved; the measuring method disclosed by the invention does not need to perform complex least-squaresiteration fitting calculation and only needs to perform filtering processing once, thus requirements on a hardware system are reduced; information of feature points of a waveform still can be relatively accurately extracted when a complete harmonic signal can not be obtained, and a lower measurement limit is lower; and excessive parameters such as a self-broadening coefficient, collision broadening coefficients of various other components and a temperature-dependent index in a database do not need to be utilized, dependence on database parameters is reduced, and application range is wider.

The invention relates to a horizontal well multi-parameter estimation method based on a conducting probe array sensor. The horizontal well multi-parameter estimation method based on the conducting probe array sensor can be used for dynamic monitoring of a low-yield-liquid horizontal well yield section and is characterized by including the following steps that before the conducting probe array sensor is utilized to measure multiple parameters in the horizontal well, firstly the conducting probe array sensor is calibrated, calibrated data are acquired, and a calibrated database is established; when parameter estimation is conducted, distance matrixes are calculated according to actual response, acquired on the spot, of the conducting probe array sensor; lastly a matching vector in the calibrated database is found out according to the position of the least element in the distance matrixes, and then an azimuth angle of the conducting probe array sensor, aqueous phase electrical conductivity and oil-water interface height in the horizontal well are estimated. The horizontal well multi-parameter estimation method based on the conducting probe array sensor has the advantages that when the conducting probe array sensor is utilized to conduct horizontal well yield section well logging, the oil-water interface height and the aqueous phase electrical conductivity in the horizontal well and the azimuth angle of the conducting probe array sensor can be simultaneously measured in an online mode, a measuring lower limit is low, accuracy is high, and reliability is good.

A uniform velocity tube of flow rate transducer consists of high pressure sampling hole at flow receiving surface, low pressure sampling hole at side surface between flow receiving surface and flow departing surface which are built on tube wall of the uniform velocity tube . It features that the said tube section is prepared to be a bullet head form so fluid is splited along two side surfaces of said tube section formed as bullet head to make a flow coefficient relatively stable when fluid flows through the tube.

The method of detecting multiple heavy metal elements simultaneously is one combined ion selecting electrode and leaching voltage-current method. In the detecting system, the electrode combination of several selecting electrodes, reference electrodes and working electrodes is adopted. For practical solution with several kinds of heavy metal elements in wide dynamic content range, the selecting ion electrodes are first used to detect heavy metals in high content, and leaching voltage-current method is then adopted. The present invention has simple sample processing program, is suitable for automatic measurement, and may be used in various fields.

The invention relates to a non-radioactivity tracing flow well logging method and process based on the pulse neutron technology in the oilfield production injection profile well logging technology. The non-radioactivity tracing flow well logging method and process based on the pulse neutron technology includes the steps of using a solution of a non-radioactive substance, such as a gadolinium compound or a boron compound, with a high heat neutron capture cross section as a tracing agent, using the neutron lifetime manner to measure the macroscopic capture cross section of fluid in a well, namely using high-strength pulse neutrons emitted by a pulse neutron generator to bombard the tracing agent, capturing heat neutrons by the tracing agent, using different well logging processes to record heat neutron time spectrums or the heat neutron counting rate of a fixed spacing detector, and calculating the flow speed of the fluid in the well and the use conditions of a thin difference layer by analyzing well logging data. The non-radioactivity tracing flow well logging method and process based on the pulse neutron technology is free of radiation risks, meets the environment-friendly requirement, is low in measuring lower limit, effectively solves the problem that an current layering injection well is low in flow and large in monitoring error, and has wide site adaptability.

The invention relates to a broadband fluorescence spectrum strain sensing method. The method comprises steps that, a broadband spectrum of a fluorescent material is utilized to carry out for strain measurement, intensity integration and spectrum band medium division processing on fluorescence spectrum band data in wave number distribution are sequentially carried out to acquire a gravity center wave number value of the fluorescence spectrum band, the gravity center wave number value is taken as the position of the spectrum band, and thereby a sensing function relation between the spectrum band gravity center and strain is acquired. Through the method, physical meaning of the spectrum band gravity center is explained, strain measurement feasibility through the spectrum band gravity center method is approved through examples, and stress magnitude can be reckoned according to a strain value and a material mechanical strength value.

The invention discloses a tracer-related traffic logging method. The tracer-related traffic logging method includes the following steps that tracers are released above a water distributor; when the tracers enter liquid injected from the water distributor to a well, tracing peaks are repeatedly traced up and down through a gamma detector to continuously measure the depth positions of the tracing peaks at different moments; when the gamma detector moves upwards and the tracing peaks are measured, the gamma detector returns downwards, and when the gamma detector moves downwards and the tracing peaks are measured, the gamma detector returns upwards till the radiation conditions detected by the gamma detector are not changed along with time any more. The tracer-related traffic logging method is a continuous measuring method, and has high measuring accuracy and the low measuring lower limit, and the water sucking capacity of all small layers can be accurately measured; the tracer-related traffic logging method has the obvious advantages for a well with the low injection volume, logging time is shortened, logging cost is reduced, and the influences of large pore paths, deep penetrating holes, contamination, channeling and leakage can be further avoided.

The invention discloses an electromagnetic jet flow flowmeter. It discloses a resist flow piece installs in the measuring tube of the jet flow flowmeter and a U type electromagnetism structure installs on the measuring tube, the first electrode, the second electrode, the third electrode installs on the measuring tube and resist flow side of the inferior of the U type electromagnetism structure. The U electromagnetism structure is composed by pair of permanent magnet and an exciting coil, controls by monolithic integrated circuit to strengthen or weaken the measuring tube magnetic field. The second electrode connects the grounding of the difference enlarge electric circuit by the wire, the first electrode, the third electrode connect the difference enlarge electric circuit input end by the wire, the difference enlarge electric circuit out-port connect the comparator electric circuit, the monolithic integrated circuit electric circuit in turn. The monolithic integrated circuit electric circuit also provides LCD monitor, pressed key input and so on electric circuit. The entire electric circuit uses a battery power supply. The merit of jet flow flowmeter is that the low power loss, the wide measuring range, the high exempt maintenance, reliable, high accuracy and so on.

The invention provides a monitoring device and a monitoring method for ultralow emission smoke. The monitoring device is used for monitoring particle size distribution and concentration of smoke in a smoke measuring area. The monitoring device comprises a multi-wavelength laser light source part and a multi-angle photoelectric detection part, wherein the multi-wavelength laser light source part comprises a plurality of laser devices, a coupler and a collimator; the laser devices are used for emitting the laser light in different wavelengths; the coupler is used for coupling the laser light in different wavelengths; the collimator is used for collimating the laser light after being coupled and acquiring the multi-wavelength laser light used for irradiating the smoke measuring area; the multi-angle photoelectric detection part comprises a plurality of photoelectric detectors, a signal modulator and a signal processor; the photoelectric detectors are respectively arranged at certain angles with the collimator and are used for distinguishing the strength of laser light with different wavelengths, receiving the multi-wavelength laser light after smoke particle scattering and converting into an electric signal; the signal modulator is used for receiving the electric signal and modulating; the signal processor is used for processing the electric signal after being modulated, so as to acquire the particle size and concentration of the smoke.

The invention relates to the field of flow detection, and provides an electromagnetic water meter transmitter based on intermittent excitation and digital signal processing. The transmitter comprisesa single-chip microcomputer minimum system, a power supply management module, an excitation driving module, a signal acquisition module, a man-machine interface module, an external storage module, anoutput module and software; and software is responsible for signal acquisition, signal processing, excitation driving, man-machine interaction and result display; the excitation driving module is usedfor driving a sensor of an electromagnetic water meter to generate a sensor signal; and the signal acquisition module is used for extracting the output signal of the sensor, converting the output signal into a digital quantity and transmitting the digital quantity to a single-chip microcomputer. An excitation mode adopts an intermittent excitation mode, and three-value wave excitation is carriedout once every period; and in algorithmic processing, amplitude demodulation is directly carried out on the acquired sensor output signal, the signal is reconstructed according to a demodulation result, the reconstructed signal is subjected to comb band-pass filtering, amplitude demodulation is carried out again, and instantaneous and accumulated flow is obtained through calculation.

A large-caliber vortex follow meter comprises a large-caliber measuring tube and a small-caliber magneto-electric vortex follow meter, which is characterized in that the small-caliber magneto-electric vortex follow meter is inserted in the large-caliber measuring tube, wherein the caliber of the large-caliber measuring tube can be up to DN600, even be much larger. Compared with an original vortex follow meter under the same caliber and the same flow velocity, the invention can release higher frequency and stronger signals, namely that the novel flow meter has the advantages of high measuring precision, low measuring lower limit and short length of straight tube sections installed back and forth. And the core portion of a small-caliber sensor can return the factory or the monitoring management office at the premise that measuring tubes with the same specification are ensured to exchange (the measuring tube for the detection is consistent with user measuring pipes) under the condition of guaranteeing the installation direction of the small-caliber sensor consistent, and the problem that the magneto-electric vortex follow meter is difficult to deliver to be detected is solved, and the installation and detachment costs in detection is greatly reduced.

The invention discloses a piezoelectric fluidic heat meter, in particular to a fluidic heat meter made of engineering plastic polyphenylene oxide (PPO). A flow choking part is installed in a measuring tube of the fluidic heat meter, two piezoelectric sensors are installed in feedback channels at both sides of the measuring tube and are connected to the input end of a differential amplification circuit, and the output end of the differential amplification circuit is sequentially connected to a comparator circuit and a singlechip circuit. The microcontroller circuit also provides circuits, such as an LCD display circuit, an infrared communication circuit, a temperature measurement circuit, and the like. A whole circuit uses one battery to supply power. The fluidic heat meter has the advantages of low power consumption, wide measuring range, free maintenance, high reliability, high accuracy, and the like.

The invention discloses a weak signal extraction system for a fluidic flowmeter based on a related amplification technology and a method. The system adopts the related amplification technology as a signal processing mode of the fluidic flowmeter. A flow choking part is installed in a measuring tube; a first electrode, a third electrode and a second electrode are respectively installed at the front side and the back side of the flow choking part; a U-shaped excitation structure is installed on the measuring tube and can carry out excitation control by being connected with an excitation drive circuit; the second electrode is connected with the ground end of a related amplification circuit through a wire; the first electrode and the third electrode are connected to a differential amplification input end of the related amplification circuit; the output end of the related amplification circuit is respectively connected with an AD conversion circuit and a singlechip circuit, and the AD conversion circuit is connected to the singlechip circuit; and the singlechip circuit also fulfills the functions of LCD display and the like. By adopting the method, the fluidic flowmeter has the advantages of lower limit, wide measurement range, high accuracy, and the like.

The invention discloses a device and method for measuring the gas pressure and components of the cavity of an extremely-small sealing device. With the device and method of the invention adopted, the measurement of the gas pressure and component content of the cavity of an extremely-small sealing device of which the gas sealing device inner cavity volume ranges from 0.005-0.1 cm <3> can be realized. The method of the invention is a measurement method combining static expansion and dynamic flow mass spectrometry. With a double-small-hole structure adopted, not only can a gas sampling quality discrimination effect be overcome, but also the pressure stability of a pressure measurement cavity and a component measurement cavity can be ensured. According to an existing method, problems exist, in a measurement process, that the pressure attenuation of the cavity of a measured sealing device is fast, mass spectrometry time sequence response is slow, and the accurate measurement of the gas components of a product of which the sealing device inner cavity volume is very small cannot be achieved. With the device and method of the invention adopted, the problems in the prior art can be solved.

The invention discloses a large-caliber magnetoelectric vortex shedding flowmeter which comprises a large-caliber sounding pipe and a small-caliber magnetoelectric vortex shedding flowmeter and is characterized in that the small-caliber magnetoelectric vortex shedding flowmeter is inserted into the large-caliber sounding pipe. The caliber of the large-caliber magnetoelectric vortex shedding flowmeter of the invention can achieve DN600 at most, even larger. Under the situation of the same caliber and flow speed, compared with the original magnetoelectric vortex shedding flowmeter, the flowmeter of the invention can release with high frequency and strong signals, that is, the novel flowmeter has the advantages of high measuring accuracy, low measurement lower limit, and short straight pipe sections installed at the front and the back; under the premise of guaranteeing the sounding pipes with the same specification are interchangeable (guaranteeing that the sounding pipe used for detection and the sounding pipe of a user are consistent), and under the situation of keeping the direction of installing the small-caliber sensor to be consistent, the core part of the small-caliber sensor is returned to the OEM or the monitoring and managing department, thus solving the problem of the difficult sending for detection of the large-caliber magnetoelectric vortex shedding flowmeter and greatly reducing the assembly and disassembly cost of the sending for detection.

The invention discloses a method for detecting antioxidant content in transformer oil by using Tafel plots, which comprises the following steps: dissolving transformer oil in a specific supporting electrolyte under ultrasonic actions, and detecting T501 antioxidant content in transformer oil by using Tafel plots by using a 6mm-diameter graphite electrode as a working electrode and using an electrochemical work station. The method for detecting T501 antioxidant content in transformer oil by using Tafel plots is established on the basis that the peak current of the T501 antioxidant characteristic peak is directly proportional to the concentration of the T501 antioxidant in transformer oil. Compared with the prior art, the method is simple to operate, has the advantages of low cost, high detection speed and high accuracy, and can implement field analysis on samples.

A high-precision closed-loop electronic circuit for a Hall current sensor acquires a current signal from a power supply end of an operational amplifier and performs static bias on an output triode; the operational amplifier and the output triode form a voltage-controlled current supply and have a variable current amplification multiple; an output end of the operational amplifier directly drives a voltage-controlled load resistor or drives a voltage-controlled load resistor with electrical level shift; and Hall elements are operated in a constant voltage manner, and the arithmetic mean value of the output voltages of a plurality of Hall elements is calculated. The present invention belongs to the field of electronic circuitry for a Hall current sensor.

The invention discloses a method used for detecting anti-oxidant content of transformer oil via differential normal pulse voltammetry. According to the method, a certain amount of the transformer oil to be tested is dissolved in a certain volume of a supporting electrolyte so as to obtained a sample to be tested; a graphite electrode with a diameter of 6mm is taken as a working electrode, an electrochemical workstation is used, differential normal pulse voltammetry is adopted, and the sample is subjected to electrochemical detection with certain conditions; and the method used for detecting anti-oxidant content of transformer oil via differential normal pulse voltammetry is established based on that, in an obtained differential normal pulse voltammetry curve, the value of a peak current of T501 anti-oxidant characteristic peak is proportional to the value of the concentration of T501 anti-oxidant. Compared with existing technology, the method is low in cost, simple in operation, rapid in detection, and high in accuracy, is capable of realizing on-site analysis of samples, and possesses great significance on rapid accurate determination of T501 anti-oxidant content of the transformer oil.

The invention discloses a photoelectric sensing system applied to rotation speed measurement. The system comprises a photoelectric sensor, a motor to be measured, a power supply module and a supporting base; the power supply module is in bidirectional connection with the photoelectric sensor, a display unit and the motor to be measured through wires; and the photoelectric sensor is in bidirectional connection with the display unit through a wireless transmit-receive module. The invention belongs to the technical field of rotation speed measurement. According to the photoelectric sensing systemapplied to the rotation speed measurement, the optical fiber sensor is adopted as a measuring main body; the short testing time of the optical fiber sensor is short; and the optical fiber sensor doesnot need to be in direct contact with the object to be measured, and has high stability. The test time of an existing optical sensor is long; if the existing optical sensor is used for rotation speedmeasurement, the measurement limit of the existing optical sensor is low; the existing optical sensor is only applicable to some motors, and fails to realize measurement for some special motors; andexisting optical sensing equipment has low stability and needs to be in actual physical contact with a object to be measured during measurement, and as a result, measurement deviation will be broughtabout easily. With the photoelectric sensing system of the invention adopted, the above problems can be solved.

The invention belongs to the technical field of weak current measurement, and particularly relates to a low leakage current resetting device applied to a capacitive integrating weak current measuringcircuit. The resetting device is connected with a capacitance integrating weak current measuring circuit (2) used for measuring weak current to be measured (1). The resetting device comprises a resetcurrent circuit (3), a multiplexer (4), a D / A converter (5), a voltage follower (6) and a logic control unit (7). The voltage follower (6) can copy the voltage of the weak current to be measured (1) as the turn-off voltage of the reset current circuit (3). The D / A converter (5) can provide turn-on voltage with adjustable polarity and magnitude for the reset current circuit (3). The resetting device further comprises a logic control unit (7) which controls the multiplexer (4) to select to output turn-off voltage or turn-on voltage, and controls the polarity and magnitude of the turn-on voltageoutput by the D / A converter (5). According to the invention, the measurement lower limit and the minimum resolution of the capacitive integrating weak current measuring circuit system can be greatly improved.

The invention discloses an ultrahigh-spectral transmittance etalon, which comprises a fixed part and light filters, wherein the light filters are of a sector structure, are alternately arranged on thefixed part and are used for filtering or shielding continuous light emitted from a light source. The upper limit of measurement of the transmittance is improved or the lower limit of measurement of the transmittance is reduced through alternately arranging at least one light filter with fixed transmittance on the fixed part and setting the sector area / central angle ratios of the light filters, the measurement range of the spectral transmittance etalon is greatly improved, meanwhile, the measurement uncertainty on the transmittance is greatly reduced, the spectral flatness of a transmittance curve is improved and the measurement uniformity on the transmittance is improved.

The invention discloses a large-caliber magnetoelectric vortex shedding flowmeter which comprises a large-caliber sounding pipe and a small-caliber magnetoelectric vortex shedding flowmeter and is characterized in that the small-caliber magnetoelectric vortex shedding flowmeter is inserted into the large-caliber sounding pipe. The caliber of the large-caliber magnetoelectric vortex shedding flowmeter of the invention can achieve DN600 at most, even larger. Under the situation of the same caliber and flow speed, compared with the original magnetoelectric vortex shedding flowmeter, the flowmeter of the invention can release with high frequency and strong signals, that is, the novel flowmeter has the advantages of high measuring accuracy, low measurement lower limit, and short straight pipe sections installed at the front and the back; under the premise of guaranteeing the sounding pipes with the same specification are interchangeable (guaranteeing that the sounding pipe used for detection and the sounding pipe of a user are consistent), and under the situation of keeping the direction of installing the small-caliber sensor to be consistent, the core part of the small-caliber sensor is returned to the OEM or the monitoring and managing department, thus solving the problem of the difficult sending for detection of the large-caliber magnetoelectric vortex shedding flowmeter and greatly reducing the assembly and disassembly cost of the sending for detection.

The invention discloses an intrinsic safety type vortex street flow sensor for oiling machine gas phase recovery measurement. The intrinsic safety type vortex street flow sensor comprises a sensor body and a safety barrier with an explosion-proof function. The sensor body comprises a shell; the circulation cavities in the inlet end and the outlet end are both of a structure which is gradually necked down from outside to inside; a piezo-electric crystal is arranged at the top of the circulation cavity in the middle of the shell, and a vertically-arranged turbulence column is arranged in the circulation cavity between the piezo-electric crystal and the inlet end; the shell provided with the turbulent flow column, the inlet end and the outlet end is of an integrally formed structure; the piezo-electric crystal is electrically connected with a filtering and amplifying circuit arranged on the circuit board; and a top cover is arranged on the shell at the upper part of the circuit board. After the gas phase entering the device passes through the turbulent flow column, Karman vortexes are formed at the circulation cavity at the lower part of the piezoelectric crystal, and weak pulse charge signals formed by the Karman vortexes are detected through the high-sensitivity piezoelectric crystal so that the detection of gas phase flow is realized, and the sensitivity is high and the reaction speed is high.

This disclosure proposes a laser particle size analyzer and a measurement method for realizing all-round measurement. The laser particle size analyzer includes a rotating laser transmitter receiver and a sample pool. The circle, the rotating laser transmitting receiver includes a rotating device and a measuring device arranged on the rotating device, the measuring device is used to emit a laser signal to the sample cell and detect an echo signal. The disclosed laser particle size analyzer and its measurement method can realize continuous and seamless reception of scattered light from 0° to 180°, and further expand the measurement lower limit of the laser particle size analyzer. The measured results are in good agreement with the nominal values, and the lower limit of measurement is close to the theoretical limit of the static light scattering method. And by using the rotating laser transmitter receiver for multi-angle measurement, and then measure the size of irregular particles at different angles.

The invention proposes a method and device for measuring the speed of fluid inside of the container or pipe. The invention uses pitot tube as the testing device of total pressure and the static pressure, uses scale pressure testing double-tube as the testing device of pressure difference, uses the reading mricoscope as the reading device of water head in the testing tube.

The invention relates to the technical field of environmental monitoring, in particular to a parallel air pollutant detection device based on mass spectrometry and a method for detecting air pollutants by using the same. The device comprises a mass spectrometer, an air distribution device, a carrier gas balancing device and a plurality of gas exchange devices. The air distribution device and the carrier gas balancing device respectively distribute the detected air and the carrier gas, and the air enters each gas exchange device for gas exchange, so that the gas exchange efficiency is improved.And compared with a single gas exchange device, the equipment space is greatly saved, the accuracy of mass spectrum detection is not influenced, and the detection limit is low.