Gas product concentration measurement method based on gas homogenization

Abstract

The application discloses a gas decomposition product concentration measuring method based on gas mixing, and the method is applied to a gas circulating device and comprises the following steps: controlling gas in a to-be-detected gas chamber to be delivered into a first gas chamber to obtain an initial gas decomposition product concentration; controlling the gas in the to-be-detected gas chamber to be delivered into a second gas chamber, then delivering the gas in the first gas chamber into the second gas chamber, then delivering the gas in the second gas chamber into the first gas chamber, and finally obtaining a target gas decomposition product concentration; determining whether the gas is in a mixing state according to the initial gas decomposition product concentration and the target gas decomposition product concentration; and if the gas is in the mixing state, taking the target gas decomposition product concentration as the total concentration of the gas decomposition product in the to-be-detected gas chamber. Whether the detected gas decomposition product concentration is accurate is determined by detecting whether the gas in the to-be-detected gas chamber and the gas decomposition product are mixed, and the gas decomposition product concentration is calculated after the gas decomposition product is mixed, so that a more accurate detection result is obtained.

Description

Technical Field

[0001] This invention relates to the field of gas concentration detection technology, and in particular to a method for measuring the concentration of gas decomposition products based on gas homogenization. Background Technology

[0002] In power systems, sulfur hexafluoride (SF6) gas, with its excellent insulation and arc-extinguishing properties, is widely used in high-voltage electrical equipment such as GIS switchgear, circuit breakers, and instrument transformers. The safe and stable operation of these devices is crucial for the safety of the power grid. However, when arcing or overheating faults occur inside the equipment, SF6 gas undergoes a decomposition reaction, generating toxic and corrosive decomposition products such as SO2, HF, and H2S. These decomposition products can cause the degradation of insulation materials, potentially leading to equipment explosions and causing serious environmental damage. Therefore, effective monitoring of SF6 decomposition products is of paramount importance for accurately assessing the insulation condition of equipment, timely diagnosing potential faults, predicting equipment lifespan, implementing condition-based maintenance, and ensuring the safe operation of the power grid.

[0003] Since the decomposition products generated by equipment failure diffuse naturally to the detection port through molecular motion, the diffusion rate is slow, making it difficult to obtain a representative gas sample during gas sampling. This results in an inaccurate reflection of the true internal state of the equipment, leading to a large error in the measured gas decomposition products. Summary of the Invention

[0004] Therefore, it is necessary to propose a gas decomposition product concentration measurement method based on gas homogenization to address the above problems. By determining whether the gas is homogenized, the accuracy and reliability of the gas decomposition product measurement results can be ensured, thereby effectively avoiding measurement errors caused by uneven gas distribution.

[0005] To achieve the above objectives, the first aspect of this application provides a method for measuring the concentration of gas decomposition products based on gas homogenization. The method is applied to a gas circulation device, which includes a first gas chamber and a second gas chamber. Both the first and second gas chambers are connected to a gas chamber to be measured. The first gas chamber is connected to the second gas chamber. The method includes:

[0006] The gas in the test chamber is controlled to be delivered to the first chamber, and before the current pressure value in the test chamber reaches the preset first pressure value, the concentration of the first gas decomposition product and the first gas flow rate are collected in real time, and the gas delivery is stopped when the current pressure value is equal to the first pressure value.

[0007] When the concentration of the first gas decomposition product is not less than a preset concentration threshold, the initial concentration of the gas decomposition product of the gas delivered from the test chamber is obtained based on the integration method, according to the concentration of the first gas decomposition product and the first gas flow rate.

[0008] The gas in the chamber to be tested is controlled to be delivered to the second chamber until the pressure between the chamber to be tested and the second chamber is balanced, and then the gas delivery is stopped.

[0009] After the gas supply from the test chamber to the second chamber is stopped, the gas in the first chamber is transported to the second chamber until the pressure in the second chamber reaches a preset second pressure value, at which point the gas supply is stopped.

[0010] After the gas transfer from the first gas chamber to the second gas chamber is stopped, the gas in the second gas chamber is transferred to the first gas chamber, and the concentration of the second gas decomposition products and the second gas flow rate are collected in real time.

[0011] Based on the integral method, the concentration of the target gas decomposition products is obtained according to the concentration of the second gas decomposition products and the second gas flow rate.

[0012] The concentration of the initial gas decomposition products is compared with the concentration of the target gas decomposition products to determine whether the gas in the test chamber is in a mixed state.

[0013] When it is determined that the gas in the test chamber is in a mixed state, the concentration of the target gas decomposition products is taken as the total concentration of the gas decomposition products in the test chamber.

[0014] Furthermore, determining whether the gas in the test chamber is in a mixed state by comparing the initial gas decomposition product concentration with the target gas decomposition product concentration specifically includes:

[0015] Obtain the volume of the second air chamber and the pressure increment of the second air chamber after the first air chamber transfers gas to the second air chamber;

[0016] The concentration factor of the gas decomposition products in the test chamber is calculated based on the volume of the second chamber, the pressure increment of the second chamber, and the flow rate of the second gas.

[0017] The gas mixing state index threshold is determined based on the concentration factor, the pressure increment of the second gas chamber, and the second pressure value.

[0018] The mixing index of the gas decomposition products in the test chamber is obtained based on the ratio of the initial gas decomposition product concentration to the target gas decomposition product concentration.

[0019] The gas in the test chamber is determined to be in a mixed state based on the mixing index of the gas decomposition products in the test chamber and the threshold value of the gas mixing state index.

[0020] Furthermore, the concentration factor of the gas decomposition products in the test chamber is calculated using the following formula:

[0021]

[0022]

[0023] In the formula, The concentration factor of the gas decomposition products in the test chamber. The volume of gas transferred from the first air chamber to the second air chamber; This represents the pressure increment in the second chamber after gas is transferred from the first chamber to the second chamber. This is the volume of the second air chamber. This is the pressure value under normal atmospheric pressure. This represents the second gas flow rate.

[0024] Furthermore, the threshold value for the gas mixing state index is calculated using the following formula:

[0025]

[0026] In the formula, The threshold value for the gas mixing state index. The concentration factor of the gas decomposition products in the test chamber. This represents the pressure increment in the second chamber after gas is transferred from the first chamber to the second chamber. This is the second pressure value.

[0027] Furthermore, the step of determining whether the gas in the test chamber is in a mixed state based on the mixing index of the gas decomposition products and the gas mixing state index threshold specifically includes:

[0028] If the difference between the homogenization index of the gas decomposition products in the test chamber and the threshold value of the gas homogenization state index is greater than the preset error threshold, then the gas in the test chamber is determined to be in an unmixed state.

[0029] If the difference between the homogenization index of the gas decomposition products in the test chamber and the threshold value of the gas homogenization state index is not greater than the error threshold value, then the gas in the test chamber is determined to be in a homogenized state.

[0030] Furthermore, the method also includes:

[0031] When it is determined that the gas in the test chamber is in an uneven state, all the gas in the first chamber is transported to the test chamber, and the process of controlling the gas in the test chamber to be transported to the first chamber continues. Before the current pressure value in the test chamber reaches the preset first pressure value, the concentration of the first gas decomposition product and the first gas flow rate are collected in real time, and the gas transport is stopped when the current pressure value is equal to the first pressure value.

[0032] Furthermore, the gas circulation device also includes: a first density meter, a flow meter, and an infrared gas analyzer, wherein the first density meter is used to connect to the gas chamber to be tested, and the flow meter and the infrared gas analyzer are both disposed between the gas chamber to be tested and the first gas chamber;

[0033] The first density meter is used to measure the pressure value of the gas chamber to be tested;

[0034] The flow meter is used to collect the gas flow rate when the gas in the gas chamber to be measured is transferred to the first gas chamber, or when the gas in the second gas chamber is transferred to the first gas chamber.

[0035] The infrared gas analyzer is used to collect the concentration of gas decomposition products when the gas in the test chamber is transferred to the first chamber, or when the gas in the second chamber is transferred to the first chamber.

[0036] Furthermore, the gas circulation device also includes: a first solenoid valve, a second solenoid valve, a pressure reducing valve, a third solenoid valve, a fourth solenoid valve, a fifth solenoid valve, and a second density gauge.

[0037] The second density meter is connected to the second air chamber and is used to measure the pressure value of the second air chamber;

[0038] One end of the first solenoid valve is connected to the gas chamber to be tested. One end of the pressure reducing valve is connected to the other end of the first solenoid valve and one end of the second solenoid valve. The other end of the second solenoid valve is connected to one gas port of the second gas chamber. The other end of the pressure reducing valve is connected to one end of the flow meter. One end of the flow meter is connected to one end of the third solenoid valve. The other end of the third solenoid valve is connected to one end of the infrared gas analyzer. The other end of the infrared gas analyzer is connected to one end of the fourth solenoid valve. The other end of the fourth solenoid valve is connected to one gas port of the first gas chamber. The other gas port of the first gas chamber is connected to one end of the fifth solenoid valve. The other end of the fifth solenoid valve is connected to the other gas port of the second gas chamber.

[0039] When the gas in the test chamber is transferred to the first chamber, the first solenoid valve, the pressure reducing valve, the third solenoid valve, and the fourth solenoid valve are opened; when the test chamber stops transferring gas to the first chamber, the first solenoid valve, the pressure reducing valve, the third solenoid valve, and the fourth solenoid valve are closed.

[0040] When the gas in the test chamber is transferred to the second chamber, the first and second solenoid valves are opened; when the test chamber stops transferring gas to the second chamber, the first and second solenoid valves are closed.

[0041] When gas in the first chamber is transferred to the second chamber, the fifth solenoid valve is opened; when gas is no longer transferred from the first chamber to the second chamber, the fifth solenoid valve is closed.

[0042] When gas in the second chamber is transferred to the first chamber, the second solenoid valve, the pressure reducing valve, the third solenoid valve, and the fourth solenoid valve are opened; when the second chamber stops transferring gas to the first chamber, the second solenoid valve, the pressure reducing valve, the third solenoid valve, and the fourth solenoid valve are closed.

[0043] Furthermore, a thermoelectric cooler is installed inside the first gas chamber to cool the first gas chamber and reduce the pressure value inside the first gas chamber, so as to realize the transfer of gas from the gas chamber to be tested to the first gas chamber.

[0044] The thermoelectric cooler is also used to heat the first air chamber and increase the pressure value inside the first air chamber, so as to realize the transfer of gas from the first air chamber to the second air chamber.

[0045] Furthermore, an electric heating wire is installed on the outside of the second air chamber to heat the second air chamber and increase the pressure value inside the second air chamber, so as to realize the transfer of gas in the second air chamber to the air chamber to be tested, or the transfer of gas in the second air chamber to the first air chamber.

[0046] The embodiments of the present invention have the following beneficial effects:

[0047] This invention proposes a method for measuring the concentration of gas decomposition products based on gas homogenization. The method is applied to a gas circulation device, which includes a first gas chamber and a second gas chamber, both of which are connected to a test chamber. The method includes: controlling the gas in the test chamber to be transported to the first gas chamber; before the current pressure value in the test chamber reaches a preset first pressure value, real-time acquisition of the concentration of a first gas decomposition product and a first gas flow rate; stopping gas transport when the current pressure value equals the first pressure value; when the concentration of the first gas decomposition product is not less than a preset concentration threshold, obtaining the initial concentration of gas decomposition products of the gas discharged from the test chamber based on an integral method, according to the first gas decomposition product concentration and the first gas flow rate; and controlling the gas in the test chamber to be transported to the second gas chamber until the concentration of the test gas decomposition product is reached. Gas delivery is stopped after the pressure between the first and second gas chambers reaches equilibrium. After the gas chamber to be tested stops supplying gas to the second chamber, gas from the first chamber is transferred to the second chamber until the pressure in the second chamber reaches a preset second pressure value, at which point gas delivery stops. After the first chamber stops supplying gas to the second chamber, gas from the second chamber is transferred to the first chamber, and the concentration of the second gas decomposition product and the second gas flow rate are collected in real time. Based on the integral method, the concentration of the target gas decomposition product is obtained according to the concentration of the second gas decomposition product, the second gas delivery duration, and the second gas flow rate. The initial gas decomposition product concentration and the target gas decomposition product concentration are compared to determine whether the gas in the test chamber is in a mixed state. If the gas in the test chamber is determined to be in a mixed state, the concentration of the target gas decomposition product is taken as the total concentration of the gas decomposition products in the test chamber. This invention determines the accuracy of the detected gas decomposition product concentration by detecting whether the gas and gas decomposition products in the test chamber are mixed, and calculates the gas decomposition product concentration after the gas decomposition products are mixed, thus obtaining more accurate detection results. Attached Figure Description

[0048] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0049] in:

[0050] Figure 1 This is a gas decomposition product concentration measurement method based on gas mixing in an embodiment of the present invention;

[0051] Figure 2 This is a structural diagram of the gas circulation device in an embodiment of the present invention;

[0052] Figure 3 This is a structural diagram of a gas diffuser in an embodiment of the present invention. Detailed Implementation

[0053] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0054] To ensure that the collected gas sample reflects the true concentration of decomposition products, it is necessary to first determine whether the collected gas sample is in a homogeneous state. If it is in a homogeneous state, the measured concentration of gas decomposition products is considered to be relatively accurate; if it is not in a homogeneous state, the measured concentration of gas decomposition products is considered to have a large error, and the gas needs to be homogenized before measurement.

[0055] Based on this, one embodiment of the present invention proposes a gas circulation device capable of realizing online, undisturbed micro-circulation of gas decomposition products. The gas circulation device mixes the gas and detects the mixing state, thereby ensuring a more accurate calculated concentration of the gas decomposition products. Please refer to... Figure 1 , Figure 1 This invention relates to a method for measuring the concentration of gas decomposition products based on gas homogenization. The method is applied to a gas circulation device, which includes a first gas chamber and a second gas chamber. Both the first and second gas chambers are connected to the gas chamber to be measured. The first gas chamber is connected to the second gas chamber. The method includes:

[0056] Step 110: Control the gas in the test chamber to be transported to the first chamber, and before the current pressure value in the test chamber reaches the preset first pressure value, collect the concentration of the first gas decomposition product and the first gas flow rate in real time, and stop the gas transport when the current pressure value is equal to the first pressure value.

[0057] In one embodiment, a flow meter and an infrared analyzer can be installed between the first gas chamber and the gas chamber to be tested, and a density meter can be installed on the gas chamber to be tested, so as to control the transfer of gas from the gas chamber to the first gas chamber, collect a gas sample once, and collect the concentration of the first gas decomposition product and the first gas flow rate of the gas sample, as well as the current pressure value in the gas chamber to be tested in real time.

[0058] In this embodiment, gas is controlled to be delivered from the test chamber to the first chamber until the current pressure in the test chamber reaches a first pressure value, at which point gas delivery stops. This first pressure value can be set randomly, but it must be ensured that the current pressure in the test chamber is not lower than a preset alarm pressure value. By monitoring the current pressure in the test chamber in real time and stopping gas delivery when the preset first pressure value is reached, it helps prevent the pressure in the test chamber from exceeding the safe range or falling below the normal operating pressure, ensuring the normal operation and safe use of the equipment, and avoiding equipment damage or safety accidents caused by abnormal pressure.

[0059] During gas transport, it is necessary to collect the concentration of the first gas decomposition product and the first gas flow rate at the sampling point in real time in order to calculate the concentration of gas decomposition products in the test chamber. By collecting the concentration of the first gas decomposition product and the first gas flow rate in real time during gas transport, relevant gas data can be obtained in a timely and accurate manner, providing a more accurate basis for subsequent calculation of gas decomposition product concentration, thereby improving the reliability of the detection results.

[0060] Step 120: When the concentration of the first gas decomposition product is not less than the preset concentration threshold, the initial concentration of the gas decomposition product of the gas delivered from the test chamber is obtained based on the integral method, according to the concentration of the first gas decomposition product and the first gas flow rate.

[0061] In this embodiment, during the process of transferring gas from the test chamber to the first chamber, it is determined in real time whether the concentration of the currently collected gas decomposition products is less than a preset concentration threshold. This concentration threshold can be 0 or a negligible concentration of gas decomposition products. If the concentration of the collected gas decomposition products is less than the concentration threshold before the current pressure value in the test chamber reaches the first pressure value, it is considered that there may be no gas decomposition products in the test chamber or that the gas decomposition products are negligible, and there is no need to further confirm the concentration of gas decomposition products. If the concentration of the collected gas decomposition products is not less than the concentration threshold before the current pressure value in the test chamber reaches the first pressure value, it is considered that there are gas decomposition products in the test chamber. In this case, the initial concentration of gas decomposition products needs to be calculated based on the first gas decomposition product concentration and the first gas flow rate using the integral method.

[0062] This embodiment only performs further calculations and analysis when the concentration reaches a threshold, avoiding misjudgments caused by background noise or other interference factors, and improving the accuracy of concentration detection. Based on the accurate concentration of the target gas decomposition products, maintenance personnel can quantitatively analyze the degree of faults inside high-voltage electrical equipment, thereby more accurately judging the health status of the equipment and helping to formulate more targeted maintenance strategies and rationally allocate maintenance time and resources.

[0063] In one embodiment, the initial concentration of gaseous decomposition products is calculated using the following formula:

[0064]

[0065] In the formula, The initial concentration of gaseous decomposition products. Let be the concentration of the first gas decomposition product collected at time t, where t is any time during the gas transport time. Let be the first gas velocity at time t.

[0066] In this embodiment of the invention, the average concentration of gas decomposition products during the gas transmission time is calculated by integration method to obtain the target gas decomposition product concentration after noise interference is eliminated, so that the measured gas decomposition product concentration is more accurate.

[0067] Step 130: Control the gas in the test chamber to be transported to the second chamber until the pressure between the test chamber and the second chamber is balanced and then stop the gas transport; after the test chamber stops transporting gas to the second chamber, transport the gas in the first chamber to the second chamber until the pressure value of the second chamber reaches the preset second pressure value and then stop the gas transport; after the first chamber stops transporting gas to the second chamber, transport the gas in the second chamber to the first chamber, and collect the concentration of the second gas decomposition products and the second gas flow rate in real time.

[0068] Specifically, after the pressure value in the test chamber reaches the first pressure value, the gas in the test chamber is transferred to the second chamber until the pressure in the test chamber and the second chamber are balanced. Once the pressure in the test chamber and the second chamber are balanced, the transfer of gas from the test chamber to the second chamber can be stopped.

[0069] Once the pressure in the test chamber and the second chamber are balanced and gas transmission stops, the gas in the first chamber is controlled to be transported into the second chamber for gas mixing, until the pressure between the first and second chambers is balanced and gas transmission stops.

[0070] Once the pressure between the first and second gas chambers is balanced and gas transmission stops, the gas in the second gas chamber is controlled to be transported to the first gas chamber for secondary gas sample sampling. During the gas sample transport process, a flow meter and an infrared gas analyzer are used to detect the concentration of the second gas decomposition products and the second gas flow rate of the gas sample after gas mixing.

[0071] In one embodiment, the first gas chamber and the second gas chamber each include an inlet and an outlet. The outlet of the first gas chamber is connected to the inlet of the second gas chamber, and the outlet of the second gas chamber is connected to the inlet of the first gas chamber. A flow meter and an infrared gas analyzer are installed between the outlet of the second gas chamber and the inlet of the first gas chamber. Based on this, gas can be supplied from the outlet of the first gas chamber to the inlet of the second gas chamber until the pressure between the first and second gas chambers is balanced and the gas supply stops. After the pressure between the first and second gas chambers is balanced and the gas supply stops, gas is supplied from the outlet of the second gas chamber to the inlet of the first gas chamber. The gas undergoes secondary gas sampling through the flow meter and the infrared gas analyzer to detect the concentration of the second gas decomposition products and the second gas flow rate of the gas sample after gas mixing. It is understood that the air inlet is not limited to air intake, but can also be used for air exhaust. This name is used for the purpose of making this embodiment easier to understand. Similarly, the air outlet is not limited to air exhaust, but can also be used for air intake. The functions of the air inlet and air outlet are not limited here.

[0072] By incorporating gas circulation and mixing, the accuracy of gas decomposition product concentration measurement is improved, avoiding measurement errors caused by gas inhomogeneity. Simultaneously, real-time acquisition of the concentration of the second gas decomposition product and the flow rate of the second gas provides a more precise basis for subsequent gas mixing state analysis, further enhancing the reliability of the detection results.

[0073] Step 140: Based on the integral method, obtain the concentration of the target gas decomposition products according to the concentration of the second gas decomposition products and the second gas flow rate.

[0074] After gas mixing and gas resampling, the concentration of the target gas decomposition products is obtained by integral calculation based on the second gas decomposition products and the second gas flow rate of the resampled gas sample.

[0075] In one embodiment, the method for calculating the concentration of the target gas decomposition products can refer to the formula for calculating the concentration of the initial gas decomposition products, and will not be repeated here.

[0076] In this embodiment of the invention, the average concentration of gas decomposition products during the gas transmission time is calculated by integration method to obtain the target gas decomposition product concentration after noise interference is eliminated, so that the measured gas decomposition product concentration is more accurate.

[0077] Step 150: Based on the comparison between the initial gas decomposition product concentration and the target gas decomposition product concentration, determine whether the gas in the test chamber is in a mixed state.

[0078] In this embodiment, the initial gas decomposition product concentration of a gas sample that has not undergone gas mixing is compared with the target gas decomposition product concentration of a gas sample that has undergone gas mixing to determine the difference between the two. If the difference between the two is large, it indicates that the gas in the test chamber is in an unmixed state; if the difference between the two is small, it indicates that the gas in the test chamber is in a mixed state.

[0079] By determining whether the gas in the test chamber is homogeneous, a gas homogenization operation can be performed in a timely manner before measurement, ensuring that the collected gas sample can accurately reflect the concentration of decomposition products. This effectively avoids measurement errors caused by gas inhomogeneity and further improves the accuracy and reliability of gas decomposition product concentration measurement.

[0080] Step 160: When it is determined that the gas in the test chamber is in a mixed state, the concentration of the target gas decomposition products is taken as the total concentration of the gas decomposition products in the test chamber.

[0081] In this embodiment, when the difference between the initial gas decomposition product concentration and the target gas decomposition product concentration is small, the gas in the test chamber is considered to be in a mixed state. At this time, the target gas decomposition product concentration can accurately reflect the gas decomposition product concentration in the test chamber. Therefore, the target gas decomposition product concentration can be used as the total concentration of gas decomposition products in the test chamber.

[0082] This invention ensures the accuracy and reliability of the measurement results of gas decomposition products by determining whether the gas is uniformly mixed. This method can effectively avoid measurement errors caused by uneven gas distribution.

[0083] In one embodiment of the present invention, when it is determined that the gas in the test chamber is in an uneven state, all the gas in the first chamber is transported to the test chamber, and the process of controlling the gas in the test chamber to be transported to the first chamber continues. Before the current pressure value in the test chamber reaches the preset first pressure value, the concentration of the first gas decomposition product and the first gas flow rate are collected in real time, and the gas transport is stopped when the current pressure value is equal to the first pressure value.

[0084] By determining the gas mixing state after each gas mixing operation, the number of mixing operations is reduced while providing higher accuracy in calculating the concentration of the target gas decomposition products.

[0085] In another embodiment of the present invention, when it is determined that the gas in the test chamber is in an unmixed state, all the gas in the first chamber is transported to the test chamber, and the gas circulation device is controlled to perform gas mixing a preset number of times. After mixing, the gas in the test chamber is transported to the first chamber again. Before the current pressure value in the test chamber reaches a preset first pressure value, the concentration of the first gas decomposition product and the first gas flow rate are collected in real time. When the current pressure value equals the first pressure value, the gas transport is stopped. Gas mixing refers to the process of controlling the gas in the test chamber to be transported between the first chamber, the second chamber, and the test chamber along a preset path and finally returning to the test chamber.

[0086] In this embodiment, the preset number of gas mixing times can be determined based on the actual situation. If the expected mixing effect can be achieved by one gas mixing, it can be set to one time, or it can be set to n times, where n is any positive integer and there is no restriction here.

[0087] This invention, through controlling the gas within the test chamber to be transported between the first chamber, the second chamber, and the test chamber along a preset path and ultimately return to the test chamber, helps to accelerate the diffusion rate of gas decomposition products within the test chamber. This allows representative gases, which are difficult to obtain during gas sampling due to their slow natural diffusion, to be fully mixed in a shorter time, ensuring that the collected gas sample more accurately reflects the overall concentration of gas decomposition products within the test chamber and avoiding measurement errors caused by local concentration differences. Furthermore, it eliminates differences in concentration variation characteristics caused by varying gas diffusion rates in different chamber volumes, making the measurement method more adaptable to test chambers of different volumes, reducing judgment errors caused by chamber volume differences, and enhancing the universality of the measurement method in various high-voltage electrical equipment.

[0088] In one feasible embodiment, a gas mixing process specifically includes:

[0089] Step 210: Control the gas in the test chamber to be delivered to the first chamber, and collect the current pressure value of the test chamber in real time; when the current pressure value in the test chamber reaches the preset third pressure value, stop the gas delivery.

[0090] In this embodiment, the gas mixing process can be achieved based on a gas circulation device. First, the gas in the test chamber is transported to the first chamber until the current pressure value in the test chamber reaches a preset third pressure value. This third pressure value can be set randomly, but it must be ensured that the current pressure value in the test chamber is not lower than a preset alarm pressure value. The third pressure value and the second pressure value can be the same or different, and there is no restriction here.

[0091] Step 220: Control the gas in the test chamber to be transported to the second chamber until the pressure between the test chamber and the second chamber is balanced, then stop the gas transmission.

[0092] Specifically, after the pressure value in the test chamber reaches the third pressure value, the gas in the test chamber is transferred to the second chamber until the pressure in the test chamber and the second chamber are balanced. Once the pressure in the test chamber and the second chamber are balanced, the transfer of gas from the test chamber to the second chamber can be stopped.

[0093] Step 230: After the gas in the test chamber stops being transferred to the second chamber, control the gas in the first chamber to be transferred to the second chamber until the pressure between the first and second chambers is balanced and then stop the gas transfer.

[0094] Specifically, once the pressure in the test chamber and the second chamber is balanced and gas transmission stops, the gas in the first chamber is controlled to be transported to the second chamber for gas mixing, until the pressure between the first and second chambers is balanced and gas transmission stops.

[0095] Step 240: After the gas transfer from the first gas chamber to the second gas chamber is stopped, control the gas in the second gas chamber to be transferred to the gas chamber to be tested until the pressure between the second gas chamber and the gas chamber to be tested is balanced and then stop the gas transfer to achieve gas mixing once.

[0096] Specifically, after the pressure between the first and second gas chambers is balanced and gas transmission stops, the gas in the second gas chamber is controlled to be transported to the gas chamber to be tested for gas mixing, until the pressure between the second and the gas chamber to be tested is balanced and gas transmission stops, thus completing one gas mixing operation.

[0097] This invention achieves gas circulation between different chambers by controlling the gas in the test chamber to be sequentially transported to the first chamber, the second chamber, and then back to the test chamber. This ensures thorough mixing of the gas decomposition products within the test chamber, accelerating the diffusion rate of the decomposition products and overcoming the slow natural diffusion rate. This results in more representative gas samples collected from thoroughly mixed gas, avoiding measurement errors caused by localized concentration differences and improving the accuracy of gas decomposition product concentration detection. Furthermore, the gas mixing operation is applicable to test chambers of different volumes, reducing differences in concentration characteristics caused by varying gas diffusion patterns in different chambers. This also reduces judgment errors due to differences in chamber volume and enhances the universality of the measurement method in various high-voltage electrical equipment.

[0098] In one embodiment of the present invention, step 150, determining whether the gas in the test chamber is in a mixed state by comparing the initial gas decomposition product concentration and the target gas decomposition product concentration, specifically includes:

[0099] Step 151: Obtain the volume of the second chamber and the pressure increment of the second chamber after the first chamber transfers gas to the second chamber.

[0100] In this embodiment, the volume of the second air chamber is obtained in advance, as well as the pressure increment of the second air chamber in step 130, which involves "transporting the gas in the first air chamber to the second air chamber until the pressure value of the second air chamber reaches the preset second pressure value and then stopping the gas delivery".

[0101] Step 152: Calculate the concentration factor of the gas decomposition products in the test chamber based on the volume of the second chamber, the pressure increment of the second chamber, and the second gas flow rate.

[0102] In one embodiment, the concentration factor of the gas decomposition products in the test chamber is calculated using the following formula:

[0103]

[0104]

[0105] In the formula, The concentration factor of the gas decomposition products in the test chamber. This represents the volume of gas transferred from the first chamber to the second chamber. This represents the pressure increment in the second chamber after gas is transferred from the first chamber to the second chamber. The volume of the second air chamber. Let be the second gas velocity at time t. This is the pressure value under normal atmospheric pressure.

[0106] Step 153: Determine the threshold value of the gas mixing state index based on the concentration factor, the pressure increment of the second gas chamber, and the second pressure value.

[0107] In one embodiment, the gas mixing state index threshold is calculated using the following formula:

[0108]

[0109] In the formula, The threshold value for the gas mixing state index. The concentration factor of the gas decomposition products in the test chamber. This represents the pressure increment in the second chamber after gas is transferred from the first chamber to the second chamber. The second pressure value is the pressure value of the second chamber after the gas is transferred from the first chamber to the second chamber.

[0110] Step 154: Based on the ratio of the initial gas decomposition product concentration to the target gas decomposition product concentration, obtain the mixing index of the gas decomposition products in the test chamber.

[0111] In this embodiment, the mixing index of the gas decomposition products in the test chamber is: ,in, The concentration of the decomposition products of the target gas. This represents the initial concentration of gas decomposition products.

[0112] Step 155: Determine whether the gas in the test chamber is in a mixed state based on the mixing index of the gas decomposition products and the threshold of the gas mixing state index.

[0113] In this embodiment, if the difference between the homogenization index of the gas decomposition products in the test chamber and the gas homogenization state index threshold is greater than a preset error threshold, the gas in the test chamber is determined to be in an unmixed state; if the difference between the homogenization index of the gas decomposition products in the test chamber and the gas homogenization state index threshold is not greater than the error threshold, the gas in the test chamber is determined to be in a mixed state.

[0114] This invention provides a systematic and accurate method for determining whether the gas in the test chamber is in a mixed state. By quantifying the indicators for determining the mixed state, errors in human judgment are reduced, making the measurement method more scientific and rigorous.

[0115] In one embodiment of the present invention, when it is determined that the gas in the test chamber is in an unmixed state, the gas circulation device is controlled to perform a preset number of gas mixing operations to achieve a gas mixing effect in the test chamber; when it is determined that the gas in the test chamber is in a mixed state, the concentration of the target gas decomposition products is... The final concentration of gas decomposition products in the test chamber Furthermore, the total amount of gas decomposition products in the gas chamber is calculated. The specific method for calculating the total amount of gas decomposition products in the gas chamber is as follows:

[0116] The volume of the test chamber is measured each time the gas is mixed, and the volume of the decomposition products in the test chamber can be calculated based on the average volume of the chamber obtained from each measurement and the concentration of the target gas decomposition products:

[0117]

[0118] in, The concentration of the decomposition products of the target gas. This represents the average volume of the air chamber. , Let be the volume of the gas chamber measured when the i-th gas is mixed.

[0119] Read the pressure value P in the test chamber when the concentration of the target gas decomposition products is calculated. Then, according to the ideal gas law, the number of moles of the decomposition products can be obtained.

[0120]

[0121] in, The number of moles of the decomposition products in gaseous form. The volume of the decomposition products in the test chamber is denoted as . R Let be the ideal gas constant. T It is the current thermodynamic temperature.

[0122] Calculate the total amount of decomposition product gases based on the number of gaseous moles and the molar mass of the decomposition products:

[0123]

[0124] in, The molar mass of the gaseous decomposition products. This represents the total amount of gas decomposition products within the gas chamber.

[0125] One embodiment of the present invention proposes a gas circulation device based on thermal cycling; please refer to the following for details. Figure 2 , Figure 2 The diagram shows the structure of the gas circulation device in this embodiment of the invention. In this embodiment, the gas circulation device includes: a first density meter 5, a flow meter 15, and an infrared gas analyzer 6. The first density meter 5 is connected to the gas chamber 16 to be tested, and both the flow meter 15 and the infrared gas analyzer 6 are positioned between the gas chamber 16 and the first gas chamber 1. The first density meter 5 measures the pressure value of the gas chamber 16; the flow meter 15 collects the gas flow rate when the gas in the gas chamber 16 is transferred to the first gas chamber 1; and the infrared gas analyzer 6 collects the concentration of gas decomposition products when the gas in the gas chamber 16 is transferred to the first gas chamber 1.

[0126] In this embodiment, the gas circulation device further includes: a first solenoid valve 7, a second solenoid valve 8, a pressure reducing valve 11, a third solenoid valve 9, a fourth solenoid valve 10, a fifth solenoid valve 12, and a second density gauge 13; the second density gauge 13 is connected to the second gas chamber 2 and is used to measure the pressure value of the second gas chamber 2; one end of the first solenoid valve 7 is connected to the gas chamber 16 to be measured; one end of the pressure reducing valve 11 is connected to the other end of the first solenoid valve 7 and one end of the second solenoid valve 8 respectively; the other end of the second solenoid valve 8 is connected to one gas port of the second gas chamber 2; the other end of the pressure reducing valve 11 is connected to one end of the flow meter 15; one end of the flow meter 15 is connected to one end of the third solenoid valve 9; the other end of the third solenoid valve 9 is connected to one end of the infrared gas analyzer 6; the other end of the infrared gas analyzer 6 is connected to one end of the fourth solenoid valve 10; the other end of the fourth solenoid valve 10 is connected to one gas port of the first gas chamber 1; and the other gas port of the first gas chamber 1 is connected to one end of the fifth solenoid valve 12. The other end of the fifth solenoid valve 12 is connected to another air port of the second air chamber 2. When the gas in the test chamber 16 is transferred to the first air chamber 1, the first solenoid valve 7, the pressure reducing valve 11, the third solenoid valve 9, and the fourth solenoid valve 10 are controlled to open. When the test chamber 16 stops transferring gas to the first air chamber 1, the first solenoid valve 7, the pressure reducing valve 11, the third solenoid valve 9, and the fourth solenoid valve 10 are controlled to close. When the gas in the test chamber 16 is transferred to the second air chamber 2, the first solenoid valve 7 and the second solenoid valve 8 are controlled to open. When the test chamber 16 stops transferring gas to the second air chamber 2, the first solenoid valve 7 and the second solenoid valve 8 are controlled to close. When the gas in the first air chamber 1 is transferred to the second air chamber 2, or the gas in the second air chamber 2 is transferred to the first air chamber 1, the fifth solenoid valve 12 is controlled to open. When the first air chamber 1 stops transferring gas to the second air chamber 2, or the second air chamber 2 stops transferring gas to the first air chamber 1, the fifth solenoid valve 12 is controlled to close.

[0127] In this embodiment, a thermoelectric cooler 4 is installed inside the cavity of the first gas chamber 1 to cool the first gas chamber 1 and reduce the pressure value inside the first gas chamber 1, so as to realize the transfer of gas in the test gas chamber 16 to the first gas chamber 1, or the transfer of gas in the second gas chamber 2 to the first gas chamber 1; the thermoelectric cooler 4 is also used to heat the first gas chamber 1 and increase the pressure value inside the first gas chamber 1, so as to realize the transfer of gas in the first gas chamber 1 to the second gas chamber 2, or the transfer of gas in the first gas chamber 1 to the test gas chamber 16.

[0128] In this embodiment, an electric heating wire 3 is installed on the outside of the second air chamber 2 to heat the second air chamber 2 and increase the pressure value inside the second air chamber 2, so as to realize the transmission of gas in the second air chamber 2 to the test air chamber 16, or the transmission of gas in the second air chamber 2 to the first air chamber 1.

[0129] In this embodiment, a gas diffuser 14 is installed at the air inlet of the second air chamber 2, so that when gas enters the second air chamber 2, the gas drives the blades 17 of the gas diffuser 14 to rotate.

[0130] The working principle of the gas circulation device proposed in this embodiment of the invention is as follows: the first gas chamber 1 is connected to the second gas chamber 2, and the fifth solenoid valve 12 controls the opening and closing of the connection between the first gas chamber 1 and the second gas chamber 2; the first gas chamber 1 is connected to the infrared gas analyzer 6 through the fourth solenoid valve 10, and the fourth solenoid valve 10 controls the opening and closing of the connection; the first gas chamber 1 is a long and narrow cavity, and a thermoelectric cooler 4 is installed inside the cavity. This device is a device that achieves cooling or heating based on the thermoelectric effect (Peltier effect). After being energized, one end absorbs heat and the other end releases heat. The reverse current can switch between the hot and cold ends; an electric heating wire is installed on the outside of the cavity of the second gas chamber 2; the second density gauge 13 monitors the gas pressure of the second gas chamber 2 in real time; the pressure reducing valve 11 is connected to the second gas chamber 2 through the second solenoid valve 8, and the second solenoid valve 8 controls the opening and closing of the connection. By controlling the operation of the heating wire 3 in the first gas chamber 1 and the thermoelectric cooler 4 in the second gas chamber 2, online thermal circulation is achieved to achieve uniform gas distribution in the gas chamber 16 to be tested, thereby eliminating the sampling deviation that is not representative. Furthermore, the pump-free thermal drive circulation mechanism can eliminate the shortcomings of insufficient sealing of the pump structure in traditional technology.

[0131] In one embodiment, the initial pressure value P0 (pressure value at 20°C) of the test chamber 16 is read through the first density table 5. The first solenoid valve 7, the pressure reducing valve 11, the third solenoid valve 9, and the fourth solenoid valve 10 are opened, and the cooling function of the thermoelectric cooler 4 is activated to cool the first chamber 1, reducing the temperature inside the first chamber 1 to the SF6 gas liquefaction temperature T0 below the initial pressure value P0. At this time, the pressure of the first chamber 1 is less than the pressure of the test chamber 16, and the gas in the test chamber 16 will enter the first chamber 1 after passing through the flow meter 15 and the infrared gas analyzer 6. The current pressure value of the test chamber 16 is read in real time through the first density table 5, and the concentration data of gas decomposition products is detected by the infrared gas analyzer 6. When the current pressure value of the test chamber 16 reaches the preset third pressure value, the first solenoid valve 7, the pressure reducing valve 11, the third solenoid valve 9, and the fourth solenoid valve 10 are closed.

[0132] In one embodiment, the first solenoid valve 7, the pressure reducing valve 11, the third solenoid valve 9, and the fourth solenoid valve 10 are opened to activate the cooling function of the thermoelectric cooler 4, cooling the first gas chamber 1 to a temperature equal to the liquefaction temperature of SF6 gas at atmospheric pressure. At this time, the pressure in the first gas chamber 1 is lower than the pressure in the gas chamber 16 to be tested. The gas in the gas chamber 16 will then enter the first gas chamber 1 after passing through the flow meter 15 and the infrared gas analyzer 6. The pressure reducing valve 11 ensures that the pressure at the front end of the infrared gas analyzer 6 is stable. Part of the gas entering the first gas chamber 1 liquefies and accumulates at the bottom of the chamber. When the gas enters the first gas chamber 1, the liquefied SF6 liquid wets part of the liquid-cooled spiral gas pipe in the first gas chamber 1, thereby rapidly cooling it to an equilibrium state through the bottom of the first gas chamber 1, improving the liquefaction efficiency of SF6 and ensuring that the gas pressure in the first gas chamber 1 is stable at atmospheric pressure, i.e., the back end of the infrared gas analyzer 6 is at atmospheric pressure. The concentration of the first gas decomposition products is detected by an infrared gas analyzer 6, and the flow rate of the first gas is detected by a flow meter 15. When the current pressure value of the gas chamber 16 reaches the preset first pressure value, the first solenoid valve 7, the pressure reducing valve 11, the third solenoid valve 9, and the fourth solenoid valve 10 are closed. Since the infrared gas analyzer 6 has the highest detection accuracy when the front-end pressure is stable and the rear-end pressure is at atmospheric pressure, this gas circulation device can effectively improve the detection accuracy.

[0133] In one embodiment, the first solenoid valve 7 and the second solenoid valve 8 are opened to allow the gas in the gas chamber 16 to be tested to quickly enter the second gas chamber 2 until the pressure is balanced, that is, when the pressure values ​​monitored by the first density gauge 5 and the second density gauge 13 are equal, the first solenoid valve 7 and the second solenoid valve 8 are closed.

[0134] In one embodiment, the fifth solenoid valve 12 is opened, and the thermoelectric cooler 4 is switched to heating function, causing the gas in the first gas chamber 1 to vaporize and pressurize before entering the second gas chamber 2. Under these conditions, the volume of the second gas chamber 2 is greater than the volume of the first gas chamber 1. A gas diffuser 14 is installed at the gas inlet of the second gas chamber 2, as can be seen from [reference needed]. Figure 3 , Figure 3 The diagram shows the structure of the gas diffuser 14 in this embodiment of the invention. It can be seen that the gas diffuser 14 includes a blade 17. When gas enters the second gas chamber 2, the gas drives the blade 17 to rotate, expanding the inlet diffusion direction and further ensuring the mixing effect of the gas within the second gas chamber 2. The gas in the first gas chamber 1 continuously heats up; the higher the temperature, the more gas enters the second gas chamber 2. When the pressure in the second gas chamber 2 is balanced with that in the first gas chamber 1, the fifth solenoid valve 12 is closed, and the thermoelectric cooler 4 stops heating and reverses its cooling process to facilitate the next gas cycle.

[0135] In one embodiment, the heating wire 3 of the second gas chamber 2 is turned on, and the first solenoid valve 7 and the second solenoid valve 8 are also turned on. The gas in the second gas chamber 2 is heated by the heating wire 3, thereby increasing the pressure of the gas in the second gas chamber 2 due to the increased temperature. The gas in the second gas chamber 2 is then refilled into the test gas chamber 16. Since the gas refilled into the test gas chamber 16 is at a higher temperature, it will form turbulence and enter the test gas chamber 16 to accelerate the movement of gas molecules in the test gas chamber 16, thereby accelerating the gas mixing process. When the pressure value recorded by the first density meter 5 no longer changes, that is, when the pressure of the test gas chamber 16 and the second gas chamber 2 is balanced, the heating wire 3 of the second gas chamber 2, the first solenoid valve 7, and the second solenoid valve 8 are turned off.

[0136] In one embodiment, the second solenoid valve 8, pressure reducing valve 11, third solenoid valve 9, and fourth solenoid valve 10 are opened to activate the cooling function of the thermoelectric cooler 4, cooling the first gas chamber 1. At this time, the pressure in the first gas chamber 1 is lower than the pressure in the second gas chamber 2. The gas in the second gas chamber 2 then enters the first gas chamber 1 after passing through the flow meter 15 and the infrared gas analyzer 6. The infrared gas analyzer 6 detects the concentration data of the second gas decomposition products, and the flow meter 15 detects the flow rate of the second gas. After the gas circulation is completed, the first and second gas chambers are heated, and the gas is refilled into the gas chamber to be tested for the next gas mixing or concentration detection.

[0137] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0138] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for measuring the concentration of gas decomposition products based on gas homogenization, characterized in that, The method is applied to a gas circulation device, which includes a first gas chamber and a second gas chamber. Both the first and second gas chambers are connected to a gas chamber to be tested. The first gas chamber is connected to the second gas chamber. The method includes: The gas in the test chamber is controlled to be delivered to the first chamber, and before the current pressure value in the test chamber reaches the preset first pressure value, the concentration of the first gas decomposition product and the first gas flow rate are collected in real time, and the gas delivery is stopped when the current pressure value is equal to the first pressure value. When the concentration of the first gas decomposition product is not less than a preset concentration threshold, the initial concentration of the gas decomposition product of the gas delivered from the test chamber is obtained based on the integration method, according to the concentration of the first gas decomposition product and the first gas flow rate. The gas in the chamber to be tested is controlled to be delivered to the second chamber until the pressure between the chamber to be tested and the second chamber is balanced, and then the gas delivery is stopped. After the gas supply from the test chamber to the second chamber is stopped, the gas in the first chamber is transported to the second chamber until the pressure in the second chamber reaches a preset second pressure value, at which point the gas supply is stopped. After the gas transfer from the first gas chamber to the second gas chamber is stopped, the gas in the second gas chamber is transferred to the first gas chamber, and the concentration of the second gas decomposition products and the second gas flow rate are collected in real time. Based on the integral method, the concentration of the target gas decomposition products is obtained according to the concentration of the second gas decomposition products and the second gas flow rate. The concentration of the initial gas decomposition products is compared with the concentration of the target gas decomposition products to determine whether the gas in the test chamber is in a mixed state. When it is determined that the gas in the test chamber is in a mixed state, the concentration of the target gas decomposition products is taken as the total concentration of the gas decomposition products in the test chamber.

2. The method as described in claim 1, characterized in that, The step of determining whether the gas in the test chamber is in a mixed state by comparing the initial gas decomposition product concentration with the target gas decomposition product concentration specifically includes: Obtain the volume of the second air chamber and the pressure increment of the second air chamber after the first air chamber transfers gas to the second air chamber; The concentration factor of the gas decomposition products in the test chamber is calculated based on the volume of the second chamber, the pressure increment of the second chamber, and the flow rate of the second gas. The gas mixing state index threshold is determined based on the concentration factor, the pressure increment of the second gas chamber, and the second pressure value. The mixing index of the gas decomposition products in the test chamber is obtained based on the ratio of the initial gas decomposition product concentration to the target gas decomposition product concentration. The gas in the test chamber is determined to be in a mixed state based on the mixing index of the gas decomposition products in the test chamber and the threshold value of the gas mixing state index.

3. The method as described in claim 2, characterized in that, The concentration factor of the gas decomposition products in the test chamber is calculated using the following formula: In the formula, The concentration factor of the gas decomposition products in the test chamber. The volume of gas transferred from the first air chamber to the second air chamber; This represents the pressure increment in the second chamber after gas is transferred from the first chamber to the second chamber. This is the volume of the second air chamber. This is the pressure value under normal atmospheric pressure. The second gas flow rate, t This refers to any moment during the gas delivery time.

4. The method as described in claim 2, characterized in that, The threshold value for the gas mixing state index is calculated using the following formula: In the formula, The threshold value for the gas mixing state index. The concentration factor of the gas decomposition products in the test chamber. This represents the pressure increment in the second chamber after gas is transferred from the first chamber to the second chamber. This is the second pressure value.

5. The method as described in claim 2, characterized in that, The step of determining whether the gas in the test chamber is in a mixed state based on the mixing index of the gas decomposition products and the gas mixing state index threshold specifically includes: If the difference between the homogenization index of the gas decomposition products in the test chamber and the threshold value of the gas homogenization state index is greater than the preset error threshold, then the gas in the test chamber is determined to be in an unmixed state. If the difference between the homogenization index of the gas decomposition products in the test chamber and the threshold value of the gas homogenization state index is not greater than the error threshold value, then the gas in the test chamber is determined to be in a homogenized state.

6. The method as described in claim 1, characterized in that, The method further includes: When it is determined that the gas in the test chamber is in an uneven state, all the gas in the first chamber is transported to the test chamber, and the process of controlling the gas in the test chamber to be transported to the first chamber continues. Before the current pressure value in the test chamber reaches the preset first pressure value, the concentration of the first gas decomposition product and the first gas flow rate are collected in real time, and the gas transport is stopped when the current pressure value is equal to the first pressure value.

7. The method as described in claim 1, characterized in that, The gas circulation device further includes: a first density meter, a flow meter, and an infrared gas analyzer, wherein the first density meter is used to connect to the gas chamber to be tested, and the flow meter and the infrared gas analyzer are both disposed between the gas chamber to be tested and the first gas chamber; The first density meter is used to measure the pressure value of the gas chamber to be tested; The flow meter is used to collect the gas flow rate when the gas in the gas chamber to be measured is transferred to the first gas chamber, or when the gas in the second gas chamber is transferred to the first gas chamber. The infrared gas analyzer is used to collect the concentration of gas decomposition products when the gas in the test chamber is transferred to the first chamber, or when the gas in the second chamber is transferred to the first chamber.

8. The method as described in claim 7, characterized in that, The gas circulation device further includes: a first solenoid valve, a second solenoid valve, a pressure reducing valve, a third solenoid valve, a fourth solenoid valve, a fifth solenoid valve, and a second density gauge. The second density meter is connected to the second air chamber and is used to measure the pressure value of the second air chamber; One end of the first solenoid valve is connected to the gas chamber to be tested. One end of the pressure reducing valve is connected to the other end of the first solenoid valve and one end of the second solenoid valve. The other end of the second solenoid valve is connected to one gas port of the second gas chamber. The other end of the pressure reducing valve is connected to one end of the flow meter. One end of the flow meter is connected to one end of the third solenoid valve. The other end of the third solenoid valve is connected to one end of the infrared gas analyzer. The other end of the infrared gas analyzer is connected to one end of the fourth solenoid valve. The other end of the fourth solenoid valve is connected to one gas port of the first gas chamber. The other gas port of the first gas chamber is connected to one end of the fifth solenoid valve. The other end of the fifth solenoid valve is connected to the other gas port of the second gas chamber. When the gas in the test chamber is transferred to the first chamber, the first solenoid valve, the pressure reducing valve, the third solenoid valve, and the fourth solenoid valve are opened; when the test chamber stops transferring gas to the first chamber, the first solenoid valve, the pressure reducing valve, the third solenoid valve, and the fourth solenoid valve are closed. When the gas in the test chamber is transferred to the second chamber, the first and second solenoid valves are opened; when the test chamber stops transferring gas to the second chamber, the first and second solenoid valves are closed. When gas in the first chamber is transferred to the second chamber, the fifth solenoid valve is opened; when gas is no longer transferred from the first chamber to the second chamber, the fifth solenoid valve is closed. When gas in the second chamber is transferred to the first chamber, the second solenoid valve, the pressure reducing valve, the third solenoid valve, and the fourth solenoid valve are opened; when the second chamber stops transferring gas to the first chamber, the second solenoid valve, the pressure reducing valve, the third solenoid valve, and the fourth solenoid valve are closed.

9. The method as described in claim 7, characterized in that, A thermoelectric cooler is installed inside the first air chamber to cool the first air chamber and reduce the pressure value inside the first air chamber, so as to realize the transfer of gas from the air chamber to be tested to the first air chamber. The thermoelectric cooler is also used to heat the first air chamber and increase the pressure value inside the first air chamber, so as to realize the transfer of gas from the first air chamber to the second air chamber.

10. The method as described in claim 7, characterized in that, An electric heating wire is installed on the outside of the second air chamber to heat the second air chamber and increase the pressure value inside the second air chamber, so as to realize the transfer of gas in the second air chamber to the air chamber to be tested, or the transfer of gas in the second air chamber to the first air chamber.

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