阅读说明：本技术 一种便携式氦气分析仪及其检测方法 (Portable helium analyzer and detection method thereof ) 是由 何镧 刘佳琪 周超 于 2021-01-12 设计创作，主要内容包括：本发明涉及一种便携式氦气分析仪及其检测方法。便携式氦气分析仪包括壳体,壳体上设有显示单元、按键单元、进气口与出气口,壳体内设有蓄电池和主控电路及分别和主控电路相连的三通电磁阀、色谱模块、热导检测器、采气泵、流量稳定模块。进气口、三通电磁阀、色谱模块、热导检测器的测量池、采气泵、流量稳定模块和出气口连成一个气路,进气口、三通电磁阀、热导检测器的参比池、采气泵、流量稳定模块和出气口连成又一个气路。测量时,先捕集参比电极的电阻变化信号,再捕集测量电极的前T秒的电阻变化信号,进行差压信号处理,再通过计算得到氦气浓度,并进行显示和存储。本发明无需载气,检测量程宽,灵敏度高,体积小,重量轻,便于携带。(The invention relates to a portable helium analyzer and a detection method thereof. The portable helium analyzer comprises a shell, wherein a display unit, a key unit, an air inlet and an air outlet are arranged on the shell, and a storage battery, a main control circuit, a three-way electromagnetic valve, a chromatographic module, a thermal conductivity detector, an air extraction pump and a flow stabilizing module which are respectively connected with the main control circuit are arranged in the shell. The air inlet, the three-way electromagnetic valve, the chromatographic module, the measuring pool of the thermal conductivity detector, the gas production pump, the flow stabilizing module and the air outlet are connected into a gas path, and the air inlet, the three-way electromagnetic valve, the reference pool of the thermal conductivity detector, the gas production pump, the flow stabilizing module and the air outlet are connected into another gas path. During measurement, the resistance change signal of the reference electrode is collected firstly, then the resistance change signal of the measurement electrode in the first T seconds is collected, differential pressure signal processing is carried out, the helium concentration is obtained through calculation, and display and storage are carried out. The invention has the advantages of no need of carrier gas, wide detection range, high sensitivity, small volume, light weight and convenient carrying.)

1. A portable helium analyzer is characterized by comprising a portable shell, wherein a display unit, a key unit, an air inlet and an air outlet are arranged on the shell, and a three-way electromagnetic valve, a chromatographic module, a thermal conductivity detector, an air collecting pump, a main control circuit and a storage battery for supplying power to the whole portable helium analyzer are arranged in the shell; the air inlet is connected with a common port of the three-way electromagnetic valve, a first air outlet of the three-way electromagnetic valve is connected with an air inlet of a measuring pool of the thermal conductivity detector through the chromatographic module, a second air outlet of the three-way electromagnetic valve is connected with an air inlet of a reference pool of the thermal conductivity detector, an air outlet of the thermal conductivity detector is connected with an air outlet through an air extraction pump, and the display unit, the key unit, the three-way electromagnetic valve, the chromatographic module, the thermal conductivity detector and the air extraction pump are respectively.

2. The portable helium analyzer of claim 1, wherein the inside of the chromatography module is provided with a wave-shaped air passage, the wave-shaped air passage is provided with a plurality of continuous serpentine bends, the bottom of the wave-shaped air passage is provided with a silicon substrate, the back of the silicon substrate is provided with a heating electrode and a temperature control electrode, the wave-shaped air passage is filled with a porous carbon nanotube to form a chromatography column, an air inlet of the wave-shaped air passage is connected with a first air outlet of the three-way electromagnetic valve, an air outlet of the wave-shaped air passage is connected with an air inlet of the measurement cell of the thermal conductivity detector, and the heating electrode and the temperature control electrode are respectively and.

3. The portable helium analyzer of claim 1, wherein the thermal conductivity detector comprises a measuring cell, a reference cell and a signal processing circuit, the measuring cell and the reference cell are symmetrically arranged, the measuring cell is internally provided with a measuring electrode, the reference cell is internally provided with a reference electrode, the measuring cell is provided with an air inlet on the measuring cell, the reference cell is provided with an air inlet on the reference cell, the measuring cell and the reference cell are both communicated with an air outlet of the thermal conductivity detector, the measuring electrode and the reference electrode are respectively connected with the signal processing circuit, and the signal processing circuit is electrically connected with the main control circuit.

4. The portable helium analyzer of claim 3, wherein the bottom of each of the measurement cell and the reference cell is a single crystal silicon substrate, the single crystal silicon substrate is provided with a comb-shaped air passage formed by etching through a deep etching technique, the measurement electrode and the reference electrode are positioned above the comb-shaped air passage, and the measurement electrode and the reference electrode are thermal sensitive comb-shaped electrodes formed by sputtering a Pt-Au alloy and performing photolithography.

5. A portable helium analyzer as claimed in claim 1, 2 or 3, comprising a flow stabilization module, wherein the gas extraction pump is connected to the gas outlet via the flow stabilization module.

6. The portable helium analyzer of claim 1, 2 or 3, wherein the main control circuit comprises a central processing unit, and a driving unit and a data storage unit respectively connected to the central processing unit, the driving unit is respectively connected to the three-way solenoid valve, the chromatographic module and the gas pump, and the thermal conductivity detector is connected to the central processing unit.

7. A method of detecting a portable helium analyzer as claimed in claim 1, 2 or 3, comprising the steps of:

the main control circuit receives an operation command of a worker, starts the gas production pump, controls the three-way electromagnetic valve to be switched to communicate a public port and a second gas outlet, gas flows in from the gas inlet, flows into the gas inlet of the reference cell of the thermal conductivity detector through the three-way electromagnetic valve, flows out from the gas outlet of the thermal conductivity detector, finally flows out from the gas outlet through the gas production pump, and a signal processing circuit in the thermal conductivity detector collects a resistance change signal of the reference electrode;

the main control circuit controls the chromatographic module to rapidly heat up, the three-way electromagnetic valve is controlled to be switched to communicate a public port and a first gas outlet, gas flows in from the gas inlet, flows into the chromatographic module through the three-way electromagnetic valve, then all components of the gas are discharged from the chromatographic module at different time sequences, then flow into the gas inlet of the measuring cell of the thermal conductivity detector, flow out from the gas outlet of the thermal conductivity detector, finally flow out from the gas outlet through the gas collection pump, and a signal processing circuit in the thermal conductivity detector collects resistance change signals of the measuring electrode in the first T seconds;

and thirdly, the signal processing circuit carries out differential pressure signal processing on the resistance change signal of the reference electrode and the resistance change signal of the measuring electrode, the differential pressure signal is transmitted to the main control circuit, the helium concentration is obtained through calculation of the main control circuit, and the helium concentration is displayed on the liquid crystal screen and stored.

Technical Field

The invention relates to the technical field of gas detection and analysis, in particular to a portable helium analyzer and a detection method thereof, which are used for the fields of environmental protection, geological exploration, earthquake prediction, precision manufacturing and the like.

Background

Helium is oneThe rare gas is abundant in the universe because it is the product of hydrogen nuclear fusion reaction on the sun or planet, but rare on earth, and mainly exists in the atmosphere, rocks and natural gas. Helium is a companion of oil and gas, is not directly connected with the generation of oil and gas, but has the characteristic physical property and chemical property of promoting the enrichment or independent accumulation of the oil and gas in an oil and gas reservoir. At present 94% of the world's helium production is extracted from natural gas. The diffusion coefficient of helium is generally less than (3-5) x 10cm²Is an inert gas that has a very strong diffusivity in most substances, so that it participates in long-distance migration and accumulation together with water, oil, natural gas, and the atmosphere. Therefore, the abnormal content of the helium in the surface has certain hydrocarbon indicating significance. Meanwhile, the helium is not gas released by organisms and is gas in the deep part of the crust, so that the abnormal content of the helium, which is generated by migration and movement of the helium in the fracture, indicates the occurrence of the crust activity and has the possibility of earthquake prediction.

The concentration analysis of common helium adopts gas chromatography or mass spectrometer to detect, wherein the mass spectrometer is used for industry leak hunting mostly, and the detection range is narrower, and distinguishes the precision and is lower, and the mass spectrometer module relies on the import mostly simultaneously, and most research and development are concentrated on integrating and the functional optimization of equipment. The gas chromatography method requires high-purity argon to accurately analyze the helium concentration, so that the application range and the application are more limited, and particularly, a portable or movable helium analyzer for field flow observation is almost rare.

Disclosure of Invention

The portable helium analyzer for flow observation and analysis and the detection method thereof have the advantages of wide detection range, high sensitivity, no need of using high-purity gas as carrier gas, small volume, low power consumption, convenience in carrying and light weight, are particularly suitable for field flow observation, and can be used for surveying faults, fracture zones and geological gas reservoirs.

The technical problem of the invention is mainly solved by the following technical scheme: the invention discloses a portable helium analyzer, which comprises a portable shell, wherein a display unit, a key unit, an air inlet and an air outlet are arranged on the shell, and a three-way electromagnetic valve, a chromatographic module, a thermal conductivity detector, an air collecting pump, a main control circuit and a storage battery for supplying power to the whole portable helium analyzer are arranged in the shell; the air inlet is connected with a common port of the three-way electromagnetic valve, a first air outlet of the three-way electromagnetic valve is connected with an air inlet of a measuring pool of the thermal conductivity detector through the chromatographic module, a second air outlet of the three-way electromagnetic valve is connected with an air inlet of a reference pool of the thermal conductivity detector, an air outlet of the thermal conductivity detector is connected with an air outlet through an air extraction pump, and the display unit, the key unit, the three-way electromagnetic valve, the chromatographic module, the thermal conductivity detector and the air extraction pump are respectively. The technical scheme does not need to use high-purity gas as carrier gas, can effectively detect and analyze the content of helium, has small volume, light weight and convenient carrying, and is particularly suitable for field detection and analysis.

Preferably, the inside wave air flue that is equipped with of chromatogram module, the wave air flue be the continuous snakelike crooked setting of a plurality of, wave air flue bottom is the silicon substrate, the back of silicon substrate is equipped with heating electrode and accuse temperature electrode, pack porous carbon nanotube and form the chromatographic column in the wave air flue, the air inlet of wave air flue with the first gas outlet of three-way solenoid valve link to each other, the gas outlet of wave air flue with the measuring cell air inlet of thermal conductivity detector link to each other, heating electrode, accuse temperature electrode respectively with the master control circuit electricity connect. The wavy air flue is bent into an adjacent concave-convex structure to form serpentine bending, the length of the chromatographic column is reduced by changing and extending the air flow path, the inner surface area of the chromatographic column is increased by the porous carbon nanotube in the chromatographic column, so that the traditional structure with the length of 5m is reduced into a miniature chromatographic module to form a chromatographic chip, and the area of the chip is not more than 6cm². The internal structure of the porous carbon nanotube is ultrafine pores, so that gases with different components are separated due to thermal power when the gases pass through the chromatographic column, helium in the gases is fully separated from gases with other components, the separation time of the helium and the gases with other components is prolonged, the 5-second interval can be reached, the helium in the sampled gases is effectively separated, and the separated helium firstly flows into the thermal conductivity detector from the chromatographic module. The main control circuit receives the feedback of the temperature control electrode and controls the heating temperature of the heating electrode in a PID control mode.

Preferably, the thermal conductivity detector comprises a measuring cell, a reference cell and a signal processing circuit, the measuring cell and the reference cell are symmetrically arranged, a measuring electrode is arranged in the measuring cell, the reference cell is internally provided with a reference electrode, a measuring cell air inlet is arranged on the measuring cell, a reference cell air inlet is arranged on the reference cell, the measuring cell and the reference cell are communicated with a thermal conductivity detector air outlet, the measuring electrode and the reference electrode are respectively connected with the signal processing circuit, and the signal processing circuit is electrically connected with the main control circuit. Helium separated by a chromatographic module firstly enters a measuring cell, a measuring electrode changes signals, sample gas enters a reference cell, a reference electrode changes signals, a signal processing circuit adopts a constant current source and a differential pressure acquisition circuit to obtain signals of the measuring electrode and the reference electrode to form bridge output signals, the signals are processed by the differential pressure signals, then are subjected to A/D conversion, noise reduction and the like, and then are transmitted to a main control circuit, and the helium concentration in the sample gas to be detected is calculated by the main control circuit and is displayed and stored.

Preferably, the bottom of each of the measuring cell and the reference cell is a monocrystalline silicon substrate, a comb-shaped air passage formed by etching through a deep etching technology is arranged on the monocrystalline silicon substrate, and the measuring electrode and the reference electrode are both arranged above the comb-shaped air passage and are thermosensitive comb-shaped electrodes formed by sputtering Pt-Au alloy on high borosilicate glass and performing photoetching. So that the gas can sufficiently flow over the surface of the electrode, thereby improving the sensitivity of the thermal conductivity detector.

Preferably, the portable helium analyzer comprises a flow stabilizing module, and the gas collecting pump is connected with the gas outlet through the flow stabilizing module. So that the flow of the collected sample gas is stable.

Preferably, the main control circuit comprises a central processing unit, and a driving unit and a data storage unit which are respectively connected with the central processing unit, the driving unit is respectively connected with the three-way electromagnetic valve, the chromatographic module and the gas extraction pump, and the thermal conductivity detector is connected with the central processing unit. The operation instruction is sent to the helium analyzer through the key unit, so that the three-way electromagnetic valve and the gas collection pump are effectively controlled, and the gas collection quantity of the sample is effectively controlled; the heating temperature of the chromatographic module is controlled by the driving unit, so that the chromatographic module is ensured to effectively separate helium components in the sample gas and the helium enters a measuring cell of the thermal conductivity detector at the earliest stage; the electric quantity signals of the measuring electrode and the reference electrode of the thermal conductivity detector are output as differential pressure signals by adopting a constant current source and a differential pressure acquisition circuit, the signals are subjected to A/D conversion, noise reduction and the like to be transmitted to a central processing unit for calculation processing, and are stored in a data storage unit and displayed in a display unit, so that good human-computer interaction is formed.

The detection method of the portable helium analyzer comprises the following steps:

the main control circuit receives an operation command of a worker, starts the gas production pump, controls the three-way electromagnetic valve to be switched to communicate a public port and a second gas outlet, gas flows in from the gas inlet, flows into the gas inlet of the reference cell of the thermal conductivity detector through the three-way electromagnetic valve, flows out from the gas outlet of the thermal conductivity detector, finally flows out from the gas outlet through the gas production pump, and a signal processing circuit in the thermal conductivity detector collects a resistance change signal of the reference electrode;

the main control circuit controls the chromatographic module to rapidly heat up, the three-way electromagnetic valve is controlled to be switched to communicate a public port and a first gas outlet, gas flows in from the gas inlet, flows into the chromatographic module through the three-way electromagnetic valve, then all components of the gas are discharged from the chromatographic module at different time sequences, then flow into the gas inlet of the measuring cell of the thermal conductivity detector, flow out from the gas outlet of the thermal conductivity detector, finally flow out from the gas outlet through the gas collection pump, and a signal processing circuit in the thermal conductivity detector collects resistance change signals of the measuring electrode in the first T seconds;

and thirdly, the signal processing circuit carries out differential pressure signal processing on the resistance change signal of the reference electrode and the resistance change signal of the measuring electrode, the differential pressure signal is transmitted to the main control circuit, the helium concentration is obtained through calculation of the main control circuit, and the helium concentration is displayed on the liquid crystal screen and stored.

The invention has the beneficial effects that: the chromatographic module and the thermal conductivity detector are of a miniature chip-level structure, the structure of each component in the shell is compact, the gas path connection between the components is short, the whole volume is small, the volume of the instrument is greatly reduced, the chromatographic column which is bent in a snake shape is adopted, the size of the chromatographic column is reduced into the size of a chip by filling the porous carbon nanotube, wave crests between helium and gases of other components are fully pulled, and the reference electrode of the thermal conductivity detector is used for measuring the change of the thermistor of the mixed gas, so that the influence of the environmental temperature, the air pressure and the humidity on the thermistor is eliminated, and meanwhile, high-purity gas is saved as carrier gas.

Drawings

FIG. 1 is a schematic diagram of one configuration of the portable helium analyzer of the present invention.

FIG. 2 is a schematic view of an air path connection configuration of the portable helium analyzer of the present invention.

FIG. 3 is a schematic diagram of a front view of a chromatography module according to the present invention.

FIG. 4 is an enlarged partial view of a chromatography column of a chromatography module according to the invention.

FIG. 5 is a schematic diagram of a rear view of a chromatography module according to the invention.

FIG. 6 is a schematic diagram of a thermal conductivity detector according to the present invention.

In the figure, 1, a shell, 2, an air inlet, 3, a three-way electromagnetic valve, 4, a chromatographic module, 5, a thermal conductivity detector, 6, a gas collecting pump, 7, a flow stabilizing module, 8, an air outlet, 9, a main control circuit, 10, a storage battery, 11, a liquid crystal touch display screen, 41, a wave-shaped air channel, 42, a porous carbon nanotube, 43, a heating electrode, 44, a temperature control electrode, 51, a measuring cell, 52, a reference cell, 53, a measuring electrode, 54, a reference electrode, 55, an air inlet of the measuring cell, 56, an air inlet of the reference cell, and 57, an air outlet of the thermal conductivity detector are arranged.

Detailed Description

The technical scheme of the invention is further specifically described by the following embodiments and the accompanying drawings.

Example (b): the portable helium analyzer of this embodiment, as shown in fig. 1, includes portable casing 1 and air inlet 2, three-way solenoid valve 3, chromatogram module 4, thermal conductivity detector 5, gas sampling pump 6, flow stabilization module 7, gas outlet 8, master control circuit 9, battery 10, liquid crystal touch display screen 11, and the battery adopts rechargeable lithium cell, for whole portable helium analyzer power supply, need not to use the alternating current, can make equipment directly detect in the field and use. The liquid crystal touch display screen is positioned on the front face of the shell, the air inlet and the air outlet are positioned on one side of the shell, and the three-way electromagnetic valve, the chromatographic module, the thermal conductivity detector, the gas production pump, the flow stabilizing module, the main control circuit and the storage battery are positioned in the shell. The liquid crystal touch display screen, the three-way electromagnetic valve, the chromatographic module, the thermal conductivity detector, the gas production pump and the flow stabilizing module are respectively connected with the main control circuit through signal lines. The liquid crystal touch display screen is used for inputting control instructions and displaying measurement results. The shell is provided with a USB port for connecting mobile storage equipment.

As shown in fig. 2, the air inlet is connected to the common port of the three-way electromagnetic valve, the first air outlet of the three-way electromagnetic valve is connected to the measurement cell air inlet 55 of the thermal conductivity detector via the chromatography module, the second air outlet of the three-way electromagnetic valve is connected to the reference cell air inlet 56 of the thermal conductivity detector, and the air outlet 57 of the thermal conductivity detector is connected to the air outlet via the gas production pump and the flow stabilization module to form a complete air path of the portable helium detector. The flow stabilizing module is used for controlling the flow rate of gas, when the three-way electromagnetic valve is connected with the chromatographic module, the flow stabilizing module controls the flow to be 10mL/min so as to ensure that the gas slowly passes through the chromatographic module, and when the three-way electromagnetic valve is directly connected with the thermal conductivity detector, the flow stabilizing module controls the flow to be 100 mL/min.

As shown in FIG. 3, FIG. 4 and FIG. 5, the inside of the chromatography module is provided with a wave-shaped air passage 41, the depth of the wave-shaped air passage is 400 μm, the width of the groove is 50 μm, the wave-shaped air passage is arranged in a plurality of continuous serpentine curves, the total length is 60m, the bottom of the wave-shaped air passage is a silicon substrate, the top of the wave-shaped air passage is closed with high borosilicate glass through bonding to form a microchip structure, the area of the chip is not more than 6cm²So that the whole chromatographic module becomes a micro chromatographic moduleAnd (5) blocking. The porous carbon nanotube 42 is filled in the wavy air passage to form a chromatographic column, the inner structure of the porous carbon nanotube is an ultrafine hole, and the aperture of the porous carbon nanotube is not more than 50nm, so that helium and gas of other components are subjected to obvious peak separation due to thermal power when passing through the chromatographic column, and the separation time is not less than 5 seconds. The back of the silicon substrate is connected with a heating electrode and a temperature control electrode, the heating electrode 43 and the temperature control electrode 44 are respectively connected with a main control circuit through signal lines, and the main control module receives the feedback of the temperature control electrode and controls the heating temperature of the heating electrode in a PID control mode.

As shown in fig. 6, the thermal conductivity detector comprises a measuring cell 51, a reference cell 52 and a signal processing circuit, the measuring cell is internally provided with a measuring electrode 53, the reference cell is internally provided with a reference electrode 54, a measuring cell air inlet 55 is arranged on the measuring cell, a reference cell air inlet 56 is arranged on the reference cell, the measuring cell and the reference cell are both communicated with a thermal conductivity detector air outlet 57, the measuring electrode and the reference electrode are respectively connected with the signal processing circuit, and the signal processing circuit is connected with the main control circuit through signal lines. The measuring pool and the reference pool use monocrystalline silicon as a substrate to form a pool body with high borosilicate glass, the silicon substrate is etched by a deep etching technology to form a comb-shaped air passage, the depth of the air passage is 100 mu m, the total length of the air passage is 2cm, and the micro thermal conductivity detector is formed. The measuring electrode and the reference electrode have the same structure, a thermistor is formed on high borosilicate glass at the top of the air passage by sputtering Pt-Au alloy, and a comb-shaped electrode is formed by photoetching and is symmetrical and consistent with the air passage, so that gas can fully flow on the surface of the electrode, and the sensitivity of the detector is improved. The measuring electrode and the reference electrode are connected to a signal processing circuit, the signal processing circuit adopts a constant current source and a differential pressure acquisition circuit to obtain signals of the measuring electrode and the reference electrode to form an electric bridge output signal, the electric bridge output signal is subjected to differential pressure signal processing, and the signals are transmitted to a main control circuit after A/D conversion, noise reduction and other processing.

The main control circuit comprises a central processing unit, and a driving unit and a data storage unit which are respectively connected with the central processing unit, wherein the driving unit is respectively connected with the three-way electromagnetic valve, the chromatographic module and the gas production pump, and the thermal conductivity detector is connected with the central processing unit. The central processing unit is a microprocessor, data transmission and command transmission are formed between the central processing unit and the liquid crystal touch display screen, the driving unit controls and drives the three-way electromagnetic valve, the heating and temperature control module, the gas production pump and the flow control module in the chromatographic module, the main control circuit receives signals sent by the signal processing circuit in the thermal conductivity detector, the helium concentration is obtained through calculation, detected data are stored in the internal data storage chip, and the detected data are displayed on the liquid crystal touch display screen at the same time, so that the man-machine interaction function is realized.

The detection method of the portable helium analyzer comprises the following steps:

firstly, an operator starts a portable helium analyzer through a liquid crystal touch display screen to determine the acquisition time of detected gas and send a detection instruction, a microprocessor receives the instruction and drives a gas extraction pump and a flow stabilization module to enter a working state through a driving unit, a three-way electromagnetic valve is controlled to be switched to a communication public port and a second gas outlet, the gas flows in from a gas inlet, flows into a reference cell gas inlet of a thermal conductivity detector through the three-way electromagnetic valve, flows out from a gas outlet of the thermal conductivity detector, flows out through the gas extraction pump and the flow stabilization module, and finally flows out from the gas outlet, and a signal processing circuit in the thermal conductivity detector collects resistance change signals of a reference electrode;

secondly, the flow stabilizing module adjusts the flow of the measured gas, the main control circuit controls the chromatographic module to rapidly heat up, the three-way electromagnetic valve is controlled to be switched to communicate the public port and the first gas outlet, the gas flows in from the gas inlet, flows into the chromatographic module through the three-way electromagnetic valve, then all components of the gas are discharged from the chromatographic module at different time sequences, then flow into the gas inlet of the measuring cell of the thermal conductivity detector, then flow out from the gas outlet of the thermal conductivity detector, pass through the gas production pump and the flow stabilizing module, and finally flow out from the gas outlet, and the signal processing circuit in the thermal conductivity detector captures the resistance change signal of the measuring electrode;

and thirdly, the signal processing circuit carries out differential pressure signal processing on the resistance change signal of the reference electrode and the resistance change signal of the measuring electrode, the differential pressure signal is transmitted to the main control circuit, the helium concentration is obtained through calculation of the main control circuit, and the helium concentration is displayed on the liquid crystal screen and stored.