Method and device for detecting pyroelectric interference by decomposition of mixed gas characteristics

Abstract

The application relates to a mixed gas characteristic product pyroelectric anti-interference detection method and device, and belongs to the field of insulating gas detection. The method comprises the following steps: sending sample gas into a chromatography tower through a carrier gas; making a first product gas flow into a detection cavity through a buffer tank, obtaining a first concentration of the first product gas through carrier gas flushing, obtaining a second concentration of the first product gas by vacuumizing the detection cavity, and obtaining a third concentration of the first product gas through further carrier gas flushing; similarly, obtaining the first to third concentrations of a second product gas and a third product gas; and obtaining the final concentrations of the product gases based on the first to third concentrations of the product gases. The method solves the problem of cross interference between characteristic product gases and between the characteristic product gases and background gas in the infrared absorption band during the detection of the characteristic product gases by directly using a spectrum method by outputting different characteristic product gases to corresponding buffer tanks in different time periods through chromatography, then conveying sample gas through a carrier gas, and detecting the sample gas through corresponding pyroelectric detectors.

Description

Technical Field

[0001] This invention relates to the field of insulating gas detection technology, and in particular to a method and apparatus for detecting the pyroelectric interference resistance of characteristic decomposition products of mixed gases. Background Technology

[0002] In the power industry, C4F7N / CO2 mixed gas, with its environmentally friendly and excellent insulating properties, is increasingly being used to replace the traditional strong greenhouse gas SF6 as the insulating medium for electrical equipment. In practical applications, detecting the concentration of characteristic byproduct gases in the C4F7N / CO2 mixed gas is of great significance for diagnosing faults such as partial discharge and overheating in electrical equipment.

[0003] Typical characteristic product gases of the C4F7N / CO2 mixture include CF4, CO, and C3F8. Currently, gas chromatography is mainly used for the analysis of C4F7N / CO2 product gases in the laboratory. However, this method is time-consuming (approximately 40 minutes) and cannot meet the needs of rapid on-site detection.

[0004] The main methods for on-site detection of SF6 product gases are electrochemical and spectroscopic methods. However, CF4 and C3F8 are chemically stable and unlikely to undergo redox reactions, making them unsuitable for electrochemical detection. Spectroscopic methods have promising applications due to their fast response and high detection accuracy. However, there is overlap between the infrared absorption bands of CF4 and C3F8, and the infrared absorption bands of CF4, CO, and C3F8 all overlap with the background gases C4F7N and CO2. Therefore, directly using spectroscopic methods to detect the concentration of characteristic product gases of C4F7N / CO2 results in significant errors.

[0005] It is evident that providing a rapid and interference-resistant detection method and apparatus for the characteristic product gases of C4F7N / CO2 mixed gas that can be applied in the field is an urgent problem to be solved. Summary of the Invention

[0006] Based on the above analysis, the present invention aims to provide a method and apparatus for detecting pyroelectric interference-resistant characteristic decomposition products of mixed gases, in order to solve the problem of the current lack of a rapid and interference-resistant detection method and apparatus for C4F7N / CO2 mixed gas characteristic product gases that can be applied in the field.

[0007] This invention provides a method and apparatus for detecting the pyroelectric interference resistance of characteristic decomposition products of mixed gases, the method comprising the following steps:

[0008] The carrier gas is loaded into the chromatography column and heated to the preset temperature; the buffer tank, detection chamber and related pipelines are evacuated; the sample gas is loaded into the metering loop and sent into the chromatography column through the carrier gas; after the sample gas passes through the chromatography column, the first to third product gases are precipitated in time sequence.

[0009] The first product gas is allowed to flow into the detection chamber through the buffer tank, and the first concentration of the first product gas is obtained by rinsing with carrier gas; the detection chamber is then evacuated to obtain the second concentration of the first product gas.

[0010] The second product gas is allowed to flow into the detection chamber through the buffer tank, and the third concentration of the first product gas and the first concentration of the second product gas are obtained by rinsing with carrier gas; the detection chamber is then evacuated to obtain the second concentration of the second product gas.

[0011] The third product gas is fed into the detection chamber through a buffer tank, and the first concentration of the third product gas is obtained by rinsing with a carrier gas; the detection chamber is evacuated to obtain the second concentration of the third product gas; the third concentration of the second product gas is obtained by further rinsing with a carrier gas.

[0012] The final concentration of each product gas is obtained based on its first, second, and third concentrations.

[0013] Furthermore, the step of allowing the first product gas to flow into the detection chamber through the buffer tank and obtaining the first concentration of the first product gas by rinsing with carrier gas includes: according to the time period during which the first product gas flows out of the chromatography column, allowing the first product gas to flow into the first detection chamber through the first buffer tank, and sending the remaining first product gas in the first buffer tank into the first detection chamber by carrier gas; obtaining the first concentration of the first product gas by using a pyroelectric detector and a concentration calibration curve.

[0014] Further, the infrared light source, the first pyroelectric detector installed in the first detection chamber, and the second pyroelectric detector installed in the second detection chamber are activated. The filter of the first pyroelectric detector only allows infrared light of the wavelengths absorbed by the first and third product gases to pass through, and the filter of the second pyroelectric detector only allows infrared light of the wavelengths absorbed by the second product gas to pass through. The voltage corresponding to the first product gas is obtained through the first pyroelectric detector, and the reference voltage of the first product gas is obtained through the second pyroelectric detector. The voltage corresponding to the first product gas is subtracted from the reference voltage to obtain the difference voltage. The concentration corresponding to the difference voltage is found on the built-in concentration calibration curve of the first product gas, and this concentration is taken as the first concentration of the first product gas.

[0015] Further, the step of allowing the second product gas to flow into the detection chamber via a buffer tank and obtaining the third concentration of the first product gas and the first concentration of the second product gas by rinsing with carrier gas includes: according to the time period during which the second product gas flows out of the chromatography column, allowing the second product gas to flow into the first detection chamber via a second buffer tank, and allowing carrier gas to flow into the first detection chamber and the second detection chamber via the first buffer tank and the second buffer tank, sending the residual first product gas in the first buffer tank and the residual second product gas in the second buffer tank into the first detection chamber and the second detection chamber by carrier gas, and obtaining the third concentration of the first product gas and the first concentration of the second product gas by using a pyroelectric detector and a concentration calibration curve.

[0016] Furthermore, the third concentration of the first product gas is obtained using the following formula:

[0017] ,

[0018] in, This indicates the third concentration of the first product gas. This indicates the current concentration of the first product gas. Indicates the length of the first detection cavity. This represents the cross-sectional area of ​​the first detection cavity. Indicates carrier gas flow rate, This indicates the time a unit volume of gas remains in the first detection chamber.

[0019] Furthermore, the final concentration of the first product gas is obtained using the following formula:

[0020] ,

[0021] in, This indicates the first concentration of the first product gas. This indicates the second concentration of the first product gas.

[0022] Further, the device includes:

[0023] The six-way valve 1 is used to connect the target gas path by switching the internal valves; the six-way valve is connected to the carrier gas outlet, sample gas outlet, quantitative ring 2 and the top side air inlet of the chromatography column 5 through pipelines.

[0024] Metering ring 2 is used for metered gas extraction;

[0025] Chromatography column 5 is filled with chromatographic reagent to allow product gases of different components in the sample gas to flow out at different times; the gas outlet at the bottom of the chromatography column is connected to the buffer tank through a pipeline.

[0026] A buffer tank is used to buffer the gas; the buffer tank is connected to the chromatography tower, carrier gas outlet, vacuum pump 18 and detection device through pipelines.

[0027] Vacuum pump 18 is connected to the buffer tank and the detection device through a pipeline. It is used to evacuate the buffer tank to pump the gas in the buffer tank to the detection device, or to evacuate the detection device to vent the gas in the detection device.

[0028] A detection device used to measure the concentration of the product gas.

[0029] Furthermore, a first heater 6 is provided on the outer wall of the chromatography column to heat the chromatography column to a preset temperature and maintain the chromatography column at that temperature; the buffer tank includes a first buffer tank 12 and a second buffer tank 13.

[0030] Furthermore, the device also includes a first to a third vent; wherein the first vent is connected to a six-way valve via a pipeline, the second vent is connected to a chromatography column via a pipeline, and the third vent is connected to a vacuum pump via a pipeline.

[0031] Furthermore, the detection device includes an infrared light source 22, a first detection cavity 23, a second detection cavity 24, a partition 25, a first pyroelectric detector 27, a second pyroelectric detector 28, and a vacuum gauge 31;

[0032] The infrared light source is located on one side of the bottom surface of the detection device to provide stable infrared light; the first pyroelectric detector is located on the other side of the bottom surface of the first detection cavity, and the filter of the first pyroelectric detector only allows infrared light of the wavelength range that can be absorbed by the first product gas and the third product gas to pass through, for measuring the voltage corresponding to the first product gas and the third product gas; the second pyroelectric detector is located on the other side of the bottom surface of the second detection cavity, and the filter of the second pyroelectric detector only allows infrared light of the wavelength range that can be absorbed by the second product gas to pass through, for measuring the voltage corresponding to the second product gas; the partition is located between the first detection cavity and the second detection cavity to separate the first detection cavity and the second detection cavity from each other; the first detection cavity and the second detection cavity are connected by a solenoid valve; a second heater 26 is provided on the outer wall of the first detection cavity and the second detection cavity to heat the first detection cavity and the second detection cavity to a preset temperature during detection and to maintain the first detection cavity and the second detection cavity at that temperature; the vacuum gauge is used to detect the vacuum degree of the detection cavity.

[0033] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0034] 1. This invention outputs different characteristic product gases to corresponding buffer tanks in time stages through chromatography, and then transports the sample gas through a carrier gas and detects it through a corresponding pyroelectric detector. This solves the problem of cross-interference in the infrared absorption bands between characteristic product gases and between them and the background gas when directly using spectroscopic methods for detection.

[0035] 2. This invention utilizes the dual-channel detection principle of a pyroelectric detector, using the output voltage of the pyroelectric detector for non-product gases as a reference voltage. This eliminates the influence caused by unstable infrared light sources and noise interference, providing a foundation for improving the accuracy and reliability of product gas concentration detection.

[0036] 3. This invention desorbs the gas to be tested by repeatedly rinsing the buffer tank and related pipelines with carrier gas and vacuum, and obtains the third concentration of each product gas by integration method. Based on the first, second and third concentrations of each product gas, the final concentration is obtained. This fully considers the concentration of the gas to be tested adsorbed by the buffer tank and related pipelines, reduces detection error and improves detection accuracy.

[0037] 4. The present invention heats the detection chamber to a preset temperature, which can improve the absorption capacity of the filter of the pyroelectric detector to infrared light, enabling the pyroelectric detector to detect lower concentrations of the analyte gas, thereby improving the detection limit of the pyroelectric detector.

[0038] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0039] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0040] Figure 1 This is a flowchart of a method for detecting pyroelectric interference resistance of characteristic decomposition products of mixed gas according to an embodiment of the present invention;

[0041] Figure 2 This is a block diagram of a pyroelectric interference-resistant detection device for characteristic decomposition products of mixed gas according to an embodiment of the present invention;

[0042] The attached figures are labeled as follows:

[0043] 1-Six-way valve; 2-Quantitative loop; 3-First solenoid valve; 4-Second solenoid valve; 5-Chromatography column; 6-First heater; 7-Third solenoid valve; 8-Fourth solenoid valve; 9-Fifth solenoid valve; 10-Sixth solenoid valve; 11-Seventh solenoid valve; 12-First buffer tank; 13-Second buffer tank; 14-Eighth solenoid valve; 15-Ninth solenoid valve; 16-Tenth solenoid valve; 17-Eleventh solenoid valve; 18-Vacuum pump; 19-Twelfth solenoid valve; 20-Thirteenth solenoid valve; 21-Fourteenth solenoid valve; 22-Infrared light source; 23-First detection chamber; 24-Second detection chamber; 25-Baffle; 26-Second heater; 27-First pyroelectric detector; 28-Second pyroelectric detector; 29-Fifteenth solenoid valve; 30-Sixteenth solenoid valve; 31-Vacuum gauge. Detailed Implementation

[0044] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0045] A specific embodiment of the present invention discloses a method for detecting the pyroelectric interference resistance of characteristic decomposition products of a mixed gas. For example... Figure 1 As shown, the method includes the following steps:

[0046] Step S1: Load the carrier gas into the chromatography column and heat the chromatography column to the preset temperature; evacuate the buffer tank, detection chamber and related pipelines; load the sample gas into the quantitative loop, and send the sample gas in the quantitative loop into the chromatography column through the carrier gas; after the sample gas passes through the chromatography column, the first to third product gases are precipitated in time sequence.

[0047] Step S2: The first product gas flows into the detection chamber through the buffer tank, and the first concentration of the first product gas is obtained by rinsing with carrier gas; the detection chamber is evacuated to obtain the second concentration of the first product gas.

[0048] Step S3: The second product gas flows into the detection chamber through the buffer tank, and the third concentration of the first product gas and the first concentration of the second product gas are obtained by rinsing with carrier gas; the detection chamber is evacuated to obtain the second concentration of the second product gas.

[0049] Step S4: The third product gas flows into the detection chamber through the buffer tank, and the first concentration of the third product gas is obtained by rinsing with carrier gas; the detection chamber is evacuated to obtain the second concentration of the third product gas; the third concentration of the second product gas is obtained by further rinsing with carrier gas.

[0050] Step S5: Obtain the final concentration of each product gas based on its first, second, and third concentrations.

[0051] Specifically, in step S1, the carrier gas is generally helium or nitrogen, used to transport the sample gas. The sample gas refers to the C4F7N / CO2 mixture and its decomposition product gases. The chromatography column is filled with a chromatography reagent to allow product gases of different components in the sample gas to flow out at different times. The buffer tank includes a first buffer tank and a second buffer tank for buffering the gas. The detection chamber includes a first detection chamber and a second detection chamber for measuring the concentration of the product gas. The quantitative loop is used for quantitative gas sampling.

[0052] It should be noted that when C4F7N / CO2 mixed gas is used as an insulating medium for high-voltage electrical equipment, it will decompose into several product gases when the high-voltage electrical equipment has faults such as partial discharge or overheating. The typical characteristic product gases include CF4, CO and C3F8.

[0053] In some embodiments, the first product gas refers to CF4, the second product gas refers to CO, and the third product gas refers to C3F8.

[0054] It should be noted that, since the concentration of the product gas is usually extremely low (typically in the ppm to ppb range), the sample gas cannot reach the chromatography column, buffer tank, and detection chamber quickly by diffusion alone. Therefore, a carrier gas with a constant flow rate is needed to deliver the sample gas into the chromatography column, buffer tank, and detection chamber. Secondly, flushing the buffer tank with the carrier gas allows any residual product gas in the buffer tank to flow into the detection chamber. Thirdly, the carrier gas prevents backflow of air and water vapor, suppresses secondary reactions of the sample gas, and improves the accuracy of product gas concentration measurement.

[0055] Specifically, the chromatographic reagent includes carbon molecular sieves, 5A molecular sieves, and polymers of ethylstyrene and divinylbenzene. Different product gases interact with the chromatographic reagent (e.g., adsorption, polar interactions). Due to the varying strengths of these interactions, components with stronger interactions are more easily retained, while those with weaker interactions are hardly retained. Therefore, the residence time of different product gases in the chromatographic reagent is different but constant, resulting in different but constant time intervals for the product gases to exit the chromatography column, thus achieving the separation of different product gases according to their time sequence.

[0056] It should be noted that since the product gases of different components elute from the chromatography column at different and constant times, the elute times of the first, second, and third product gases can be determined in advance through experiments. The first product gas elutes first, and the third product gas elutes last.

[0057] In some embodiments, the time period during which CF4 flows out of the chromatography column is denoted as [t]. CF4,start, t CF4,end ], where t CF4,start t represents the moment when CF4 begins to flow out of the chromatography column. CF4,end This represents the moment when CF4 stops flowing out of the chromatography column. The time interval during which CO flows out of the chromatography column is denoted as [t]. CO,start , t CO,end ], where t CO,start t represents the moment when CO begins to flow out of the chromatography column. CO,end This represents the moment when CO stops flowing out of the chromatography column. The time interval during which C3F8 flows out of the chromatography column is denoted as [t]. C3F8,start , t C3F8,end ], where t C3F8,start t represents the moment when C3F8 begins to flow out of the chromatography column. C3F8,end This indicates the moment when C3F8 stops flowing out of the chromatography column.

[0058] Furthermore, by switching the first channel of the multi-way valve, the carrier gas is loaded into the chromatography column, the corresponding solenoid valve is opened to allow the carrier gas to flow through the chromatography column, and the first heater installed on the outer wall of the chromatography column is started to heat the chromatography column to the preset temperature and maintain the chromatography column at that temperature.

[0059] It should be noted that the multi-way valve refers to an industrial valve with three or more gas paths, used to connect the target gas path by switching internal valves to achieve the loading and venting of carrier gas and sample gas. By keeping the carrier gas flowing through the chromatography column, the carrier gas flushes the chromatography column, so that other residual gases in the column are removed. The first heater is started to heat the chromatography column, and the column temperature is waited for to rise to the preset temperature (e.g., 100°C) and maintained at that temperature, while the carrier gas continues to flow during the heating process.

[0060] Understandably, since the product gases such as C3F8 have high boiling points, the chromatography column needs to operate at a preset temperature so that the product gas to be tested can flow out of the chromatography column.

[0061] Further, open the corresponding solenoid valve and start the vacuum pump to evacuate the buffer tank, detection chamber and related pipelines to the preset vacuum level.

[0062] Specifically, the first buffer tank, the second buffer tank, the first detection chamber, the second detection chamber, and the pipelines in which they are located are evacuated, and the vacuum level is monitored with a vacuum gauge. When the preset vacuum level is reached, it is maintained for a certain period of time (e.g., 5 minutes) and then the corresponding solenoid valves and vacuum pumps opened during the evacuation are closed to stop the evacuation.

[0063] Furthermore, by switching the second channel of the multi-way valve to load the sample gas into the quantitative loop, the corresponding solenoid valve is opened to allow the sample gas to flow through the quantitative loop. After waiting for a preset time, the third channel of the multi-way valve is switched to send the sample gas in the quantitative loop into the chromatography column through the carrier gas.

[0064] Specifically, by maintaining the flow of sample gas through the metering loop, the residual gases in the metering loop are removed and the loop is filled with sample gas. After waiting for a preset time, the third channel of the multi-port valve is switched to load carrier gas into the metering loop, and the sample gas in the metering loop is sent into the chromatography column by carrier gas blowing.

[0065] Specifically, in step S2, the step of allowing the first product gas to flow into the detection chamber through the buffer tank and obtaining the first concentration of the first product gas by rinsing with carrier gas includes: according to the time period during which the first product gas flows out of the chromatography tower, allowing the first product gas to flow into the first detection chamber through the first buffer tank, and sending the remaining first product gas in the first buffer tank into the first detection chamber by carrier gas; obtaining the first concentration of the first product gas by using a pyroelectric detector and a concentration calibration curve.

[0066] In some embodiments, a corresponding solenoid valve is opened according to the time period during which the first product gas flows out of the chromatography column, allowing the first product gas to flow into the first buffer tank. A vacuum pump is then started to draw the first product gas from the first buffer tank into the first detection chamber. A corresponding solenoid valve is opened to allow carrier gas to flow into the first buffer tank via the second buffer tank. The vacuum pump is then started to draw the gas from the first buffer tank into the first detection chamber within a set time period. This process involves flushing the first buffer tank with carrier gas, causing any residual first product gas (e.g., first product gas adsorbed on the inner wall of the first buffer tank) to desorb and be sent into the first detection chamber. At this point, the majority of the first product gas separated by the chromatography column flows into the first detection chamber.

[0067] In some embodiments, an infrared light source, a first pyroelectric detector disposed in a first detection cavity, and a second pyroelectric detector disposed in a second detection cavity are activated. The filter of the first pyroelectric detector allows only infrared light in wavelengths absorbed by the first and third product gases to pass through, and the filter of the second pyroelectric detector allows only infrared light in wavelengths absorbed by the second product gas to pass through. The voltage corresponding to the first product gas is obtained through the first pyroelectric detector, and a reference voltage for the first product gas is obtained through the second pyroelectric detector. The voltage corresponding to the first product gas is subtracted from the reference voltage to obtain the difference voltage. The concentration corresponding to the difference voltage is found on the built-in concentration calibration curve of the first product gas, and this concentration is taken as the first concentration of the first product gas.

[0068] It should be noted that at this time, the first detection chamber contains only the carrier gas and the first product gas, while the second detection chamber is a vacuum. The carrier gas (usually helium or nitrogen) does not absorb infrared light. Because the first product gas absorbs infrared light of a specific wavelength, the intensity of that wavelength of infrared light received by the first pyroelectric detector changes, causing a change in the output voltage of the first pyroelectric detector. This output voltage is the voltage corresponding to the first product gas. Since the second detection chamber is a vacuum, the intensity of the infrared light received by the second pyroelectric detector remains unchanged, and the output voltage of the second pyroelectric detector remains unchanged. This output voltage is the reference voltage for the first product gas.

[0069] Understandably, since the reference voltage is not affected by the first product gas, subtracting the voltage corresponding to the first product gas from its reference voltage to obtain the difference voltage can eliminate the influence caused by the instability of the infrared light source, noise interference, etc., and provide a basis for improving the accuracy and reliability of the first product gas concentration detection.

[0070] It should be noted that, based on the concentration calibration curve of the first product gas built into the first pyroelectric detector, the concentration corresponding to the voltage difference is found on the concentration calibration curve, and this concentration is output as the first concentration of the first product gas, denoted as: C CF4,1 .

[0071] In some embodiments, during detection, a second heater disposed on the outer wall of the first detection chamber is activated to heat the first detection chamber to a preset temperature, such as 50°C, and the first detection chamber is maintained at that temperature.

[0072] It is understandable that heating the detection chamber to a preset temperature can improve the absorption capacity of the pyroelectric detector's filter for infrared light. The higher the temperature, the better the absorption effect of the filter for infrared light, enabling the pyroelectric detector to detect lower concentrations of the analyte gas, thereby improving the detection limit of the pyroelectric detector.

[0073] Furthermore, the vacuum pump is started to evacuate the first detection chamber to a preset vacuum level, thereby obtaining the second concentration of the first product gas.

[0074] It should be noted that, to avoid excessive pressure within the first detection chamber due to subsequent gas entering, and to provide a low concentration environment for the next step of detecting the third concentration of the first product gas, after obtaining the first concentration of the first product gas, the corresponding solenoid valve is opened to evacuate the first detection chamber to a preset vacuum level. Similarly, the voltage corresponding to the first product gas after evacuation is obtained through the first pyroelectric detector, and the reference voltage of the first product gas is obtained through the second pyroelectric detector. The voltage corresponding to the first product gas after evacuation is subtracted from the reference voltage to obtain the difference voltage. The concentration corresponding to the difference voltage is found on the built-in concentration calibration curve of the first product gas, and this concentration is taken as the second concentration of the first product gas, denoted as: C CF4,2 .

[0075] Understandably, the error generated by the pyroelectric detector during the detection process is related to the magnitude of the current detected value; the larger the detected value, the greater the absolute error. Therefore, this invention evacuates the first detection chamber, providing a basis for reducing the error in detecting the third concentration of the first product gas.

[0076] Specifically, in step S3, the step of allowing the second product gas to flow into the detection chamber through the buffer tank and obtaining the third concentration of the first product gas and the first concentration of the second product gas by rinsing with carrier gas includes: according to the time period during which the second product gas flows out of the chromatography column, allowing the second product gas to flow into the first detection chamber through the second buffer tank, and allowing the carrier gas to flow into the first detection chamber and the second detection chamber through the first buffer tank and the second buffer tank, sending the residual first product gas in the first buffer tank and the residual second product gas in the second buffer tank into the first detection chamber and the second detection chamber through the carrier gas, and obtaining the third concentration of the first product gas and the first concentration of the second product gas through the pyroelectric detector and the concentration calibration curve.

[0077] It should be noted that, due to t CF4,end Time and t CO,start Since the timing is relatively close and the vacuuming time for the first detection chamber is relatively long, the second product gas flowing out of the chromatography column enters the second buffer tank first.

[0078] In some embodiments, the corresponding solenoid valve is opened according to the time period during which the second product gas flows out of the chromatography column, allowing the second product gas to flow into the second buffer tank. A vacuum pump is then started to draw the second product gas from the second buffer tank to the first detection chamber. The corresponding solenoid valve is opened to allow the carrier gas to flow through the first and second buffer tanks into the first and second detection chambers. Since the carrier gas flows through the first buffer tank, the residual first product gas in the first buffer tank will further desorb and be sent into the first detection chamber (this portion of the first product gas will cause a change in the intensity of the infrared light in this band received by the first pyroelectric detector). Then, it flows through the first detection chamber into the second detection chamber. The infrared light source, the first pyroelectric detector, and the second pyroelectric detector are started. The voltage corresponding to the first product gas at the current time s is obtained through the first pyroelectric detector, and the reference voltage of the first product gas at the current time is obtained through the second pyroelectric detector. The voltage corresponding to the first product gas at the current time is subtracted from the reference voltage to obtain the voltage difference at the current time. The concentration corresponding to the voltage difference at the current time is found on the built-in concentration calibration curve of the first product gas. This concentration is taken as the concentration of the first product gas at the current time, expressed as: C. CF4,s The third concentration of the first product gas is obtained using the following formula:

[0079] ,

[0080] in, This indicates the third concentration of the first product gas. This indicates the current concentration of the first product gas. Indicates the length of the first detection cavity. This represents the cross-sectional area of ​​the first detection cavity. Indicates carrier gas flow rate, This indicates the time a unit volume of gas remains in the first detection chamber.

[0081] It should be noted that in step S3, the solenoid valve between the first and second detection chambers is opened, connecting the two chambers. When gas flows into the first detection chamber, it will flow into the second detection chamber under pressure. The third concentration of the first product gas is then determined using the integral method described above.

[0082] In some embodiments, when C CF4,s When the value is 0, the vacuum pump is started, and the gas in the second buffer tank is drawn into the first detection chamber within a set time. That is, the second buffer tank is flushed with carrier gas, causing the residual second product gas in the second buffer tank (e.g., the second product gas adsorbed on the inner wall of the second buffer tank) to desorb and be sent into the first and second detection chambers. At this time, most of the second product gas separated by the chromatography column flows into the first and second detection chambers.

[0083] In some embodiments, the voltage corresponding to the second product gas is obtained through the second pyroelectric detector, and the reference voltage of the second product gas is obtained through the first pyroelectric detector. The voltage corresponding to the second product gas is subtracted from the reference voltage to obtain the voltage after difference. The concentration corresponding to the voltage after difference is found on the built-in concentration calibration curve of the second product gas, and this concentration is taken as the first concentration of the second product gas.

[0084] It should be noted that at this time, the first detection chamber contains only the carrier gas and the second product gas, while the second detection chamber contains only the carrier gas, the first product gas, and the second product gas. Because the second product gas absorbs infrared light of a specific wavelength, the intensity of that infrared light received by the second pyroelectric detector changes, causing a change in the output voltage of the second pyroelectric detector. This output voltage is the voltage corresponding to the second product gas. Since the first detection chamber contains only the carrier gas and the second product gas, the intensity of the infrared light received by the first pyroelectric detector remains unchanged, and the output voltage of the first pyroelectric detector remains unchanged. This output voltage is the reference voltage for the second product gas.

[0085] Similarly, since the reference voltage is not affected by the second product gas, the voltage corresponding to the second product gas can be subtracted from the reference voltage to obtain the difference voltage, which can eliminate the influence caused by the instability of the infrared light source and noise interference, thus providing a basis for improving the accuracy and reliability of the second product gas concentration detection.

[0086] It should be noted that, based on the concentration calibration curve of the second product gas built into the second pyroelectric detector, the concentration corresponding to the voltage difference is found on the concentration calibration curve, and this concentration is output as the first concentration of the second product gas, denoted as: C CO,1 .

[0087] In some embodiments, during detection, a second heater disposed on the outer wall of the second detection chamber is activated to heat the second detection chamber to a preset temperature, such as 50°C, and the second detection chamber is maintained at that temperature.

[0088] Furthermore, the vacuum pump is started to evacuate the first and second detection chambers to a preset vacuum level, thereby obtaining the second concentration of the second product gas.

[0089] It should be noted that after obtaining the first concentration of the second product gas, the corresponding solenoid valve is opened to evacuate the first and second detection chambers to a preset vacuum level. Similarly, the voltage corresponding to the second product gas after evacuation is obtained through the second pyroelectric detector, and the reference voltage of the second product gas is obtained through the first pyroelectric detector. The voltage corresponding to the second product gas after evacuation is subtracted from the reference voltage to obtain the difference voltage. The concentration corresponding to the difference voltage is found on the built-in concentration calibration curve of the second product gas, and this concentration is taken as the second concentration of the second product gas, denoted as: C CO,2 .

[0090] Specifically, in step S4, the step of allowing the third product gas to flow into the detection chamber through the buffer tank and obtaining the first concentration of the third product gas by rinsing with carrier gas includes: according to the time period during which the third product gas flows out of the chromatography tower, allowing the third product gas to flow into the first detection chamber through the first buffer tank, and sending the remaining third product gas in the first buffer tank into the first detection chamber by carrier gas; obtaining the first concentration of the third product gas by using a pyroelectric detector and a concentration calibration curve.

[0091] In some embodiments, a corresponding solenoid valve is opened according to the time period during which the third product gas flows out of the chromatography column, allowing the third product gas to flow into the first buffer tank. A vacuum pump is then started to draw the third product gas from the first buffer tank into the first detection chamber. Alternatively, a corresponding solenoid valve is opened to allow carrier gas to flow into the first buffer tank. The vacuum pump is then started to draw the gas from the first buffer tank into the first detection chamber within a set time period. This process involves flushing the first buffer tank with carrier gas, causing any residual third product gas (e.g., third product gas adsorbed on the inner wall of the first buffer tank) to desorb and be sent into the first detection chamber. At this point, the majority of the third product gas separated by the chromatography column flows into the first detection chamber.

[0092] In some embodiments, the voltage corresponding to the third product gas is obtained by a first pyroelectric detector, and the reference voltage of the third product gas is obtained by a second pyroelectric detector. The voltage corresponding to the third product gas is subtracted from the reference voltage to obtain the voltage after difference. The concentration corresponding to the voltage after difference is found on the built-in concentration calibration curve of the third product gas, and this concentration is taken as the first concentration of the third product gas.

[0093] It should be noted that at this time, the first detection chamber contains only the carrier gas and the third product gas, while the second detection chamber is a vacuum. Because the third product gas absorbs infrared light of a specific wavelength, the intensity of that infrared light received by the first pyroelectric detector changes, causing a change in the output voltage of the first pyroelectric detector. This output voltage is the voltage corresponding to the third product gas. Since the second detection chamber is a vacuum, the intensity of the infrared light received by the second pyroelectric detector remains unchanged, and the output voltage of the second pyroelectric detector remains unchanged. This output voltage is the reference voltage for the third product gas.

[0094] It should be noted that, based on the concentration calibration curve of the third product gas built into the first pyroelectric detector, the concentration corresponding to the voltage difference is found on the concentration calibration curve, and this concentration is output as the first concentration of the third product gas, denoted as: C C3F8,1 .

[0095] In some embodiments, during detection, a second heater disposed on the outer wall of the first detection chamber is activated to heat the first detection chamber to a preset temperature, such as 50°C, and the first detection chamber is maintained at that temperature.

[0096] Furthermore, the vacuum pump is started to evacuate the first detection chamber to a preset vacuum level, thereby obtaining the second concentration of the third product gas.

[0097] It should be noted that after obtaining the first concentration of the third product gas, the corresponding solenoid valve is opened to evacuate the first detection chamber to a preset vacuum level. Similarly, the voltage corresponding to the third product gas after evacuation is obtained through the first pyroelectric detector, and the reference voltage of the third product gas is obtained through the second pyroelectric detector. The voltage corresponding to the third product gas after evacuation is subtracted from the reference voltage to obtain the difference voltage. The concentration corresponding to the difference voltage is found on the built-in concentration calibration curve of the third product gas. This concentration is taken as the second concentration of the third product gas, denoted as: C C3F8,2 .

[0098] Further, the corresponding solenoid valves are opened, and the vacuum pump is started, drawing the carrier gas through the first and second buffer tanks to the first and second detection chambers. Because the carrier gas flows through the first and second buffer tanks, the residual second and third product gases in these tanks are further desorbed and sent into the first detection chamber, then into the second detection chamber. The voltage of the third product gas at the current time s is obtained through the first pyroelectric detector, and the reference voltage of the third product gas at the current time is obtained through the second pyroelectric detector. The voltage corresponding to the third product gas at the current time is subtracted from the reference voltage to obtain the voltage difference at the current time. The concentration corresponding to the voltage difference at the current time is found on the built-in concentration calibration curve of the third product gas, and this concentration is taken as the concentration of the third product gas at the current time, denoted as: C. C3F8,s The third concentration of the third product gas is obtained using the following formula:

[0099] ,

[0100] in, This indicates the third concentration of the third product gas. This indicates the concentration of the third product gas at the current moment.

[0101] Furthermore, the voltage corresponding to the current time s of the second product gas is obtained through the second pyroelectric detector, and the reference voltage of the second product gas at the current time is obtained through the first pyroelectric detector. The voltage corresponding to the current time of the second product gas is subtracted from the reference voltage to obtain the voltage after difference at the current time. The concentration corresponding to the voltage after difference at the current time is found on the built-in concentration calibration curve of the second product gas. This concentration is taken as the concentration of the second product gas at the current time, expressed as: C CO,s The third concentration of the second product gas is obtained using the following formula:

[0102] ,

[0103] in, This indicates the third concentration of the second product gas. This indicates the concentration of the second product gas at the current moment.

[0104] It should be noted that when C C3F8,s and C CO,s When both values ​​are 0, it indicates that the second and third product gases have been thoroughly rinsed, and the detection should be stopped.

[0105] Specifically, in step S5, the final concentration of the first product gas is obtained using the following formula:

[0106] ;

[0107] The final concentration of the second product gas can be obtained using the following formula:

[0108] ;

[0109] The final concentration of the third product gas can be obtained using the following formula:

[0110] .

[0111] Another specific embodiment of the present invention discloses a pyroelectric interference-resistant detection device for characteristic decomposition products of mixed gases. For example... Figure 2 As shown, the device includes:

[0112] The six-way valve 1 is used to connect the target gas path by switching the internal valves; the six-way valve is connected to the carrier gas outlet, sample gas outlet, quantitative ring 2 and the top side air inlet of the chromatography column 5 through pipelines.

[0113] Metering ring 2 is used for metered gas extraction;

[0114] Chromatography column 5 is filled with chromatographic reagent to allow product gases of different components in the sample gas to flow out at different times; the gas outlet at the bottom of the chromatography column is connected to the buffer tank through a pipeline.

[0115] A buffer tank is used to buffer the gas; the buffer tank is connected to the chromatography tower, carrier gas outlet, vacuum pump 18 and detection device through pipelines.

[0116] Vacuum pump 18 is connected to the buffer tank and the detection device through a pipeline. It is used to evacuate the buffer tank to pump the gas in the buffer tank to the detection device, or to evacuate the detection device to vent the gas in the detection device.

[0117] A detection device used to measure the concentration of the product gas.

[0118] Specifically, the device further includes a first to a third air vent; wherein the first air vent is connected to a six-way valve via a pipeline, the second air vent is connected to a chromatography column via a pipeline, and the third air vent is connected to a vacuum pump via a pipeline.

[0119] Specifically, a first heater 6 is provided on the outer wall of the chromatography column to heat the chromatography column to a preset temperature and maintain the chromatography column at that temperature. The buffer tanks include a first buffer tank 12 and a second buffer tank 13.

[0120] Specifically, the detection device includes an infrared light source 22, a first detection cavity 23, a second detection cavity 24, a partition 25, a first pyroelectric detector 27, a second pyroelectric detector 28, and a vacuum gauge 31. The infrared light source is located on one side of the bottom surface of the detection device to provide stable infrared light. The first pyroelectric detector is located on the other side of the bottom surface of the first detection cavity. Its filter allows only infrared light of the wavelengths absorbed by the first and third product gases to pass through, and is used to measure the voltages corresponding to the first and third product gases. The second pyroelectric detector is located on the other side of the bottom surface of the second detection cavity. Its filter allows only infrared light of the wavelengths absorbed by the second product gas to pass through, and is used to measure the voltage corresponding to the second product gas. The partition is located between the first and second detection cavities to separate them. The first and second detection cavities are connected by a solenoid valve. A second heater 26 is provided on the outer wall of the first and second detection chambers to heat the first and second detection chambers to a preset temperature during detection and to maintain the first and second detection chambers at that temperature. The vacuum gauge is used to detect the vacuum level of the detection chambers.

[0121] In specific implementation, the first, second, and third concentrations of each product gas are obtained according to the above-mentioned pyroelectric interference-resistant detection method for characteristic decomposition products of C4F7N / CO2 mixed gas, which will not be elaborated here. First, connect the ports 41 and 42 of the six-way valve, open the first solenoid valve 3 and the third solenoid valve 7, load the carrier gas into the chromatography column, and keep the carrier gas flowing through the chromatography column. Start the first heater 6 to heat the chromatography column 5 to the preset temperature and keep the chromatography column at that temperature. Open the ninth solenoid valve 15, the tenth solenoid valve 16, the eleventh solenoid valve 17, the twelfth solenoid valve 19, the fourteenth solenoid valve 21, and the fifteenth solenoid valve 29, and start the vacuum pump 18 to evacuate the first buffer tank 12, the second buffer tank 13, the first detection chamber 23, the second detection chamber 24, and related pipelines. Monitor the vacuum degree through the vacuum gauge 31. When the preset vacuum degree is reached, maintain it for a period of time (e.g., 5 minutes), and then close the corresponding solenoid valves opened for vacuuming and the vacuum pump to stop vacuuming. Connect ports 43 and 44, and ports 45 and 46 of the six-way valve, and open the second solenoid valve 4 to allow the sample gas to flow through the metering loop 2. After waiting for a preset time, connect ports 41 and 46, and ports 42 and 43 of the six-way valve to load the carrier gas into the metering loop. The sample gas in the metering loop is then sent into the chromatography column by carrier gas blowing.

[0122] Secondly, timing begins from the moment the sample gas is blown into the chromatography column from the quantitative loop, that is, from the moment the six-way valve's ports 41 and 46, and ports 42 and 43 are connected. CF4,startThe third solenoid valve 7 is closed at all times, while the sixth solenoid valve 10, the ninth solenoid valve 15, the eleventh solenoid valve 17, and the fourteenth solenoid valve 21 are opened to allow the first product gas to flow into the first buffer tank. The vacuum pump is then started to draw the first product gas from the first buffer tank into the first detection chamber. CF4,end The sixth solenoid valve 10 is closed at all times, while the third solenoid valve 7, the fifth solenoid valve 9, and the eighth solenoid valve 14 are opened. Gas in the chromatography column continues to be vented. The fifth solenoid valve 9 and the eighth solenoid valve 14 close after one minute of opening. At this time, the carrier gas flows into the first buffer tank via the second buffer tank. The vacuum pump is started, and the gas in the first buffer tank is drawn into the first detection chamber within a set time. The infrared light source 22, the first pyroelectric detector 27, and the second pyroelectric detector 28 are activated. During detection, the second heater 26 is activated to heat the first detection chamber to a preset temperature and maintain the first detection chamber at that temperature, thereby obtaining the first concentration of the first product gas, expressed as: C. CF4,1 Open the twelfth solenoid valve 19 and the sixteenth solenoid valve 30, start the vacuum pump to evacuate the first detection chamber to the preset vacuum level, and obtain the second concentration of the first product gas, expressed as: C CF4,2 .

[0123] Next, timing begins from the moment the sample gas is blown into the chromatography column from the quantitative loop, t CO,start The third solenoid valve 7 is closed at all times, while the fourth solenoid valve 8, the tenth solenoid valve 16, the eleventh solenoid valve 17, and the fourteenth solenoid valve 21 are opened to allow the second product gas to flow into the second buffer tank. The vacuum pump 18 is then started to pump the second product gas from the second buffer tank into the first detection chamber. At t CO,end The fourth solenoid valve 8, the eleventh solenoid valve 17, the vacuum pump 18, and the fourteenth solenoid valve 21 are closed at all times, while the seventh solenoid valve 11, the eighth solenoid valve 14, the thirteenth solenoid valve 20, and the fifteenth solenoid valve 29 are opened. This allows the carrier gas to flow through the first buffer tank and the second buffer tank into the first detection chamber and the second detection chamber, thereby obtaining the third concentration of the first product gas, denoted as C. CF4,3 When C CF4,s When the concentration is 0, close the thirteenth solenoid valve 20, open the eleventh solenoid valve 17, the fourteenth solenoid valve 21, and the twelfth solenoid valve 19, and start the vacuum pump. Within a set time, the gas in the second buffer tank is drawn into the first detection chamber, causing the residual second product gas in the second buffer tank to desorb and be sent into the first and second detection chambers. Close the fifteenth solenoid valve 29, and start the first pyroelectric detector 27 and the second pyroelectric detector 28. During detection, start the second heater 26 to heat the second detection chamber to a preset temperature and maintain the second detection chamber at that temperature, thereby obtaining the first concentration of the second product gas, denoted as: C. CO,1Open solenoid valves 12 (19), 15 (29), and 16 (30) to start the vacuum pump and evacuate the first and second detection chambers to a preset vacuum level, obtaining the second concentration of the second product gas, denoted as C. CO,2 .

[0124] Finally, timing begins from when the sample gas is blown into chromatography column 5 from the quantitative loop, t C3F8,star The third solenoid valve 7 is closed at all times, while the sixth solenoid valve 10, ninth solenoid valve 15, eleventh solenoid valve 17, and fourteenth solenoid valve 21 are opened to allow the third product gas to flow into the first buffer tank. The vacuum pump is then started to draw the third product gas from the first buffer tank into the first detection chamber. C3F8,end The sixth solenoid valve 10 is closed, and the seventh solenoid valve 11 is opened, allowing the gas in the chromatography column to continue to be vented. The seventh solenoid valve 11 closes after one minute of opening, and the vacuum pump is started to draw the gas from the first buffer tank to the first detection chamber within a set time. The first pyroelectric detector 27 and the second pyroelectric detector 28 are activated. During detection, the second heater 26 is activated to heat the first detection chamber to a preset temperature and maintain the first detection chamber at that temperature, thereby obtaining the first concentration of the third product gas, denoted as C. C3F8,1 Open the twelfth solenoid valve 19 and the sixteenth solenoid valve 30, start the vacuum pump to evacuate the first detection chamber to the preset vacuum level, and obtain the second concentration of the third product gas, expressed as: C C3F8,2 Open the fifth solenoid valve 9, the ninth solenoid valve 15, the tenth solenoid valve 16, the eleventh solenoid valve 17, the fourteenth solenoid valve 21, and the fifteenth solenoid valve 29, start the vacuum pump 18, and pump the carrier gas through the first buffer tank and the second buffer tank to the first detection chamber and the second detection chamber. Activate the first pyroelectric detector 27 and the second pyroelectric detector 28 to obtain the third concentration of the second product gas and the third concentration of the third product gas. When C C3F8,s and C CO,s When all values ​​are 0, the vacuum pump, infrared light source, first pyroelectric detector, and second pyroelectric detector are turned off to stop detection. The final concentration of each product gas is obtained based on its first, second, and third concentrations.

[0125] Compared with the prior art, the beneficial effects of the pyroelectric interference-resistant detection method and device for characteristic decomposition products of C4F7N / CO2 mixed gas provided by the present invention are as follows:

[0126] 1. This invention outputs different characteristic product gases to corresponding buffer tanks in time stages through chromatography, and then transports the sample gas through a carrier gas and detects it through a corresponding pyroelectric detector. This solves the problem of cross-interference in the infrared absorption bands between characteristic product gases and between them and the background gas when directly using spectroscopic methods for detection.

[0127] 2. This invention utilizes the dual-channel detection principle of a pyroelectric detector, using the output voltage of the pyroelectric detector for non-product gases as a reference voltage. This eliminates the influence caused by unstable infrared light sources and noise interference, providing a foundation for improving the accuracy and reliability of product gas concentration detection.

[0128] 3. This invention desorbs the gas to be tested by repeatedly rinsing the buffer tank and related pipelines with carrier gas and vacuum, and obtains the third concentration of each product gas by integration method. Based on the first, second and third concentrations of each product gas, the final concentration is obtained. This fully considers the concentration of the gas to be tested adsorbed by the buffer tank and related pipelines, reduces detection error and improves detection accuracy.

[0129] 4. The present invention heats the detection chamber to a preset temperature, which can improve the absorption capacity of the filter of the pyroelectric detector to infrared light, enabling the pyroelectric detector to detect lower concentrations of the analyte gas, thereby improving the detection limit of the pyroelectric detector.

[0130] Those skilled in the art will understand that all or part of the processes of the methods described in the above embodiments can be implemented by a computer program instructing related hardware, and the program can be stored in a computer-readable storage medium. The computer-readable storage medium may be a disk, optical disk, read-only memory, or random access memory, etc.

[0131] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for detecting the pyroelectric interference resistance of characteristic decomposition products of a mixed gas, characterized in that, The method includes the following steps: The carrier gas is loaded into the chromatography column and heated to the preset temperature; the buffer tank, detection chamber and related pipelines are evacuated; the sample gas is loaded into the metering loop and sent into the chromatography column through the carrier gas; after the sample gas passes through the chromatography column, the first to third product gases are precipitated in time sequence. The process involves allowing the first product gas to flow into the detection chamber via a buffer tank, and then flushing it with a carrier gas to obtain the first concentration of the first product gas. Specifically, based on the time interval during which the first product gas flows out of the chromatography column, the first product gas is allowed to flow into the first detection chamber via a first buffer tank, and the remaining first product gas in the first buffer tank is sent into the first detection chamber via a carrier gas. The first concentration of the first product gas is obtained using a pyroelectric detector and a concentration calibration curve. This includes: activating an infrared light source, a first pyroelectric detector installed in the first detection chamber, and a second pyroelectric detector installed in the second detection chamber. The voltage corresponding to the first product gas is obtained through the first pyroelectric detector, and a reference voltage for the first product gas is obtained through the second pyroelectric detector. The voltage corresponding to the first product gas is subtracted from the reference voltage to obtain the difference voltage. The concentration corresponding to the difference voltage is found on the built-in concentration calibration curve of the first product gas, and this concentration is taken as the first concentration of the first product gas. The filter of the first pyroelectric detector only allows infrared light in the wavelength range that can be absorbed by the first and third product gases to pass through, and the filter of the second pyroelectric detector only allows infrared light in the wavelength range that can be absorbed by the second product gas to pass through. The process involves evacuating the detection chamber to obtain a second concentration of the first product gas. This includes: starting a vacuum pump to evacuate the first detection chamber to a preset vacuum level; obtaining the voltage corresponding to the first product gas after evacuation using a first pyroelectric detector; obtaining a reference voltage for the first product gas using a second pyroelectric detector; subtracting the voltage corresponding to the first product gas after evacuation from the reference voltage to obtain a differential voltage; finding the concentration corresponding to the differential voltage on a built-in concentration calibration curve for the first product gas; and using this concentration as the second concentration of the first product gas. The process also involves allowing the second product gas to flow into the detection chamber via a buffer tank, and rinsing with a carrier gas to obtain a third concentration of the first product gas and a first concentration of the second product gas. Specifically, based on the time interval from when the second product gas flows out of the chromatography column, the second product gas is allowed to flow into the first detection chamber via a second buffer tank, and a carrier gas is allowed to flow into the first and second detection chambers via the first and second buffer tanks. The carrier gas carries the residual first product gas in the first buffer tank and the residual second product gas in the second buffer tank into the first and second detection chambers. The third concentration of the first product gas and the first concentration of the second product gas are obtained using a pyroelectric detector and the concentration calibration curve. The process involves activating an infrared light source, a first pyroelectric detector, and a second pyroelectric detector. The voltage of the first product gas at the current time *s* is obtained through the first pyroelectric detector, and the reference voltage of the first product gas at the current time is obtained through the second pyroelectric detector. The voltage corresponding to the current product gas at the current time is subtracted from the reference voltage to obtain the difference voltage. The concentration corresponding to this difference voltage is then found on the built-in concentration calibration curve of the first product gas, and this concentration is taken as the concentration of the first product gas at the current time. The third concentration of the first product gas is obtained using the following formula: ， in, This indicates the third concentration of the first product gas. This indicates the current concentration of the first product gas. Indicates the length of the first detection cavity. This represents the cross-sectional area of ​​the first detection cavity. Indicates carrier gas flow rate, This indicates the time a unit volume of gas remains in the first detection chamber. The voltage corresponding to the second product gas is obtained through the second pyroelectric detector, and the reference voltage of the second product gas is obtained through the first pyroelectric detector. The voltage corresponding to the second product gas is subtracted from the reference voltage to obtain the voltage after difference. The concentration corresponding to the voltage after difference is found on the built-in concentration calibration curve of the second product gas, and this concentration is taken as the first concentration of the second product gas. The process of obtaining a second concentration of the second product gas by evacuating the detection chamber includes: starting a vacuum pump to evacuate the first and second detection chambers to a preset vacuum level to obtain a second concentration of the second product gas; obtaining the voltage corresponding to the second product gas after evacuation through a second pyroelectric detector, obtaining a reference voltage of the second product gas through a first pyroelectric detector, subtracting the voltage corresponding to the second product gas after evacuation from the reference voltage to obtain the difference voltage, finding the concentration corresponding to the difference voltage on the built-in concentration calibration curve of the second product gas, and taking this concentration as the second concentration of the second product gas. The process involves: allowing the third product gas to flow into the detection chamber via a buffer tank, and obtaining the first concentration of the third product gas by rinsing with a carrier gas; including: allowing the third product gas to flow into the first detection chamber via a first buffer tank based on the time period during which the third product gas flows out of the chromatography column, and sending the residual third product gas in the first buffer tank into the first detection chamber via a carrier gas; obtaining the first concentration of the third product gas through a pyroelectric detector and a concentration calibration curve; specifically, obtaining the voltage corresponding to the third product gas through a first pyroelectric detector, obtaining the reference voltage of the third product gas through a second pyroelectric detector, subtracting the voltage corresponding to the third product gas from the reference voltage to obtain the difference voltage, finding the concentration corresponding to the difference voltage on the built-in concentration calibration curve of the third product gas, and taking this concentration as the first concentration of the third product gas; The process of obtaining a second concentration of the third product gas by evacuating the detection chamber includes: starting a vacuum pump to evacuate the first detection chamber to a preset vacuum level to obtain a second concentration of the third product gas; obtaining the voltage corresponding to the third product gas after evacuation through a first pyroelectric detector, obtaining a reference voltage of the third product gas through a second pyroelectric detector, subtracting the voltage corresponding to the third product gas after evacuation from the reference voltage to obtain the difference voltage, finding the concentration corresponding to the difference voltage on the built-in concentration calibration curve of the third product gas, and taking this concentration as the second concentration of the third product gas. The third concentration of the second product gas and the third concentration of the third product gas are obtained through further carrier gas rinsing. Specifically, the corresponding solenoid valves are opened, the vacuum pump is started, and the carrier gas is drawn through the first and second buffer tanks to the first and second detection chambers. The carrier gas flows through the first and second buffer tanks, causing the residual second and third product gases in the first and second buffer tanks to be further desorbed and sent into the first detection chamber, and then flow into the second detection chamber. The third concentration of the second product gas and the third concentration of the third product gas are obtained through a pyroelectric detector and a concentration calibration curve. The voltage corresponding to the third product gas at the current time s is obtained through the first pyroelectric detector, and the reference voltage of the third product gas at the current time is obtained through the second pyroelectric detector. The voltage corresponding to the third product gas at the current time is subtracted from the reference voltage to obtain the voltage at the current time. The concentration corresponding to the voltage at the current time is found on the built-in concentration calibration curve of the third product gas, and this concentration is taken as the concentration of the third product gas at the current time. The third concentration of the third product gas is obtained through the following formula: ， in, This indicates the third concentration of the third product gas. This indicates the current concentration of the third product gas; The voltage corresponding to the second product gas at the current time s is obtained through the second pyroelectric detector, and the reference voltage of the second product gas at the current time is obtained through the first pyroelectric detector. The voltage corresponding to the second product gas at the current time is subtracted from the reference voltage to obtain the voltage at the current time. The concentration corresponding to the voltage at the current time is found on the built-in concentration calibration curve of the second product gas, and this concentration is taken as the concentration of the second product gas at the current time. The third concentration of the second product gas is obtained through the following formula: ， in, This indicates the third concentration of the second product gas. This indicates the current concentration of the second product gas; The final concentration of each product gas is obtained based on its first, second, and third concentrations. The final concentration of the first product gas can be obtained using the following formula: ； The final concentration of the second product gas can be obtained using the following formula: ； The final concentration of the third product gas can be obtained using the following formula: 。 2. A device for detecting pyroelectric interference resistance of characteristic decomposition products of a mixed gas for implementing the pyroelectric interference resistance detection method for characteristic decomposition products of a mixed gas as described in claim 1, characterized in that, The device includes: A six-way valve (1) is used to connect the target gas path by switching the internal valve; the six-way valve is connected to the carrier gas outlet, sample gas outlet, metering ring (2) and the top side air inlet of the chromatography column (5) through pipelines; A metering loop (2) is used for metered gas extraction; The chromatography column (5) is filled with chromatography reagent to allow the product gases of different components in the sample gas to flow out at different times; the gas outlet at the bottom of the chromatography column is connected to the buffer tank through a pipeline. A buffer tank is used to buffer the gas; the buffer tank is connected to the chromatography tower, the carrier gas outlet, the vacuum pump (18) and the detection device through pipelines; A vacuum pump (18) is connected to the buffer tank and the detection device through a pipeline. It is used to evacuate the buffer tank to pump the gas in the buffer tank to the detection device, or to evacuate the detection device to vent the gas in the detection device. A detection device used to measure the concentration of the product gas; The outer wall of the chromatography column is provided with a first heater (6) for heating the chromatography column to a preset temperature and maintaining the chromatography column at that temperature; the buffer tank includes a first buffer tank (12) and a second buffer tank (13). The detection device includes an infrared light source (22), a first detection chamber (23), a second detection chamber (24), a first pyroelectric detector (27), a second pyroelectric detector (28), and a vacuum gauge (31). The infrared light source is located on one side of the bottom surface of the detection device to provide stable infrared light; the first pyroelectric detector is located on the other side of the bottom surface of the first detection chamber, and the filter of the first pyroelectric detector only allows infrared light of the wavelength range that can be absorbed by the first product gas and the third product gas to pass through, for measuring the voltage corresponding to the first product gas and the third product gas; the second pyroelectric detector is located on the other side of the bottom surface of the second detection chamber, and the filter of the second pyroelectric detector only allows infrared light of the wavelength range that can be absorbed by the second product gas to pass through, for measuring the voltage corresponding to the second product gas; the first detection chamber and the second detection chamber are connected by a solenoid valve; the vacuum gauge is used to detect the vacuum degree of the detection chamber.

3. The pyroelectric interference-resistant detection device for characteristic decomposition products of mixed gas according to claim 2, characterized in that, The device further includes a first to a third vent; wherein the first vent is connected to a six-way valve via a pipeline, the second vent is connected to a chromatography column via a pipeline, and the third vent is connected to a vacuum pump via a pipeline.

4. The pyroelectric interference-resistant detection device for characteristic decomposition products of mixed gas according to claim 2, characterized in that, The partition is located between the first detection chamber and the second detection chamber, and is used to separate the first detection chamber and the second detection chamber from the middle; a second heater (26) is provided on the outer wall of the first detection chamber and the second detection chamber, which is used to heat the first detection chamber and the second detection chamber to a preset temperature during detection, and to keep the first detection chamber and the second detection chamber at that temperature.

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