A gas concentration detection method based on NDIR technology

Abstract

The present invention relates to the technical field of gas concentration detection based on NDIR technology, and discloses a gas concentration detection method based on NDIR technology. Selecting a standard gas sample with a known concentration is the basis of the experiment to ensure data accuracy. Containers of the same volume and serial numbers help eliminate errors and facilitate operation. The constant temperature box provides a stable environment, controls temperature and humidity, and ensures consistent experimental conditions. A temperature and humidity range with a 15% floating amplitude is set to simulate different conditions, find the best compensation strategy, and improve measurement accuracy and stability. The mixed gas collection device collects samples comprehensively, multiple air inlet pipes and different height settings ensure sample representativeness, and valves and vacuum pumps control the flow rate to ensure sample stability. The monomer gas collection device collects samples at specific points in a centralized manner. The errors caused by changes in temperature and humidity are corrected by the compensation method, and the final result is more accurate.

Description

Technical Field

[0001] The invention relates to the technical field of gas concentration detection based on NDIR technology, and in particular to a gas concentration detection method based on NDIR technology. Background Art

[0002] NDIR (non-dispersive infrared) technology is a widely used technology for gas detection, with the advantages of high sensitivity, high selectivity and non-contact measurement. The working principle of NDIR gas detection technology is based on the absorption characteristics of gas molecules to infrared light of a specific wavelength. When infrared light passes through the gas to be tested, gases of different concentrations will absorb infrared light of different intensities. By measuring the intensity of the absorbed infrared light, the concentration of the gas can be inferred.

[0003] In practical applications, NDIR gas detection technology is widely used in environmental monitoring, industrial process control, safety detection and other fields. With the improvement of environmental awareness and the advancement of industrial technology, the requirements for the accuracy and reliability of gas concentration detection are becoming higher and higher. However, the impact of changes in temperature and humidity on gas detection is a problem that must be solved. Fluctuations in temperature and humidity will cause changes in the absorption characteristics of infrared light, thereby affecting the measurement results of gas concentration. Therefore, in actual detection, temperature and humidity must be compensated to improve the accuracy of the measurement results. At the same time, the collection of target gases in the space to be measured needs to be comprehensively collected. To this end, this case intends to propose a method that provides accurate humidity and temperature range compensation, while providing a collection method for multiple gases to be measured to test the concentration of the gas to be measured. Summary of the invention

[0004] The present invention provides a gas concentration detection method based on NDIR technology, which helps solve the problems mentioned in the above background technology.

[0005] The present invention provides the following technical solution: a gas concentration detection method based on NDIR technology, comprising:

[0006] Select a standard gas sample with a known concentration of the gas to be tested;

[0007] Place the standard gas samples in containers of the same volume and label them with serial numbers, namely the first standard gas sample, the second standard gas sample, and so on, the Nth standard gas sample;

[0008] The containers containing the standard gas samples are placed in a thermostatic box capable of controlling temperature and humidity;

[0009] Set multiple reference temperature points, and set a temperature range with an upper and lower floating range of 15% based on the reference temperature points;

[0010] Set multiple reference humidity points, and set a humidity range with an upper and lower floating range of 15% based on the reference humidity points;

[0011] While keeping the humidity constant, measure the compensation value of temperature in different temperature ranges;

[0012] When keeping the temperature constant, measure the compensation value of humidity in different humidity ranges;

[0013] A mixed gas collecting device is used to collect the gas in the space to be measured, which is recorded as the mixed gas to be measured. The mixed gas collecting device includes a plurality of air inlet pipes with the same diameter, the air inlets are arranged at different heights, the air inlet valves and the air pump are arranged at the air inlet, and the air outlets of the air inlet pipes are connected to the same gas collection container;

[0014] A monomer gas collecting device is used to collect the gas in the space to be measured, wherein the monomer gas collecting device comprises an air inlet pipe, a valve and a vacuum pump are arranged at the air inlet, and the outlet of the air inlet pipe is connected to a gas collection container with the same volume;

[0015] The concentration of the gas to be measured in the space target is calculated by the compensation method.

[0016] Optionally, while keeping the humidity constant, measuring the compensation value of the temperature in different temperature ranges specifically includes:

[0017] Select half of the number of the constant temperature boxes as samples for measuring temperature compensation values ​​in different temperature ranges;

[0018] Adjust the humidity of each incubator to be consistent;

[0019] Set the unit temperature adjustment value;

[0020] Let the minimum temperature be T min ;

[0021] Adjust the temperature of the thermostat box to T min , T min +1×unit temperature adjustment value...T min +(N / 2)×unit temperature adjustment value;

[0022] Use the NDIR sensor to measure the concentration of the standard gas at each temperature to be tested, and record the temperature and the corresponding measured concentration;

[0023] Plot the temperature as the horizontal axis and the measured concentration as the vertical axis to obtain a scatter plot of concentration versus temperature;

[0024] The scatter plot was fitted using linear regression to obtain a linear relationship between concentration and temperature;

[0025] The different temperature ranges are respectively recorded as a first temperature range, a second temperature range, ... an Mth temperature range;

[0026] Assume that the linear relationship of the first temperature range is C1=a1+b1×T1, where T1 represents the difference between the temperature in the first temperature range and the reference temperature in the first temperature range;

[0027] Substituting the temperature value and the concentration value corresponding to the temperature value in the first temperature range into the linear relationship formula of the first temperature range to calculate the a1 value and the b1 value, wherein the b1 value is the temperature compensation value of the first temperature range;

[0028] Assume that the linear relationship of the second temperature range is C2=a2+b2×T2, where T2 represents the difference between the temperature in the second temperature range and the reference temperature in the second temperature range;

[0029] Substituting the temperature value and the concentration value corresponding to the temperature value in the second temperature range into the linear relationship formula of the second temperature range to calculate the a2 value and the b2 value, wherein the b2 value is the temperature compensation value of the second temperature range;

[0030] The linear relationship of the third temperature range, ... the linear relationship of the Mth temperature range are sequentially set to obtain the temperature compensation value in the corresponding temperature range.

[0031] Optionally, while keeping the temperature constant, measuring the compensation value of humidity in different humidity ranges specifically includes:

[0032] Select half of the number of the constant temperature boxes as samples for measuring humidity compensation values ​​in different humidity ranges;

[0033] Adjust the temperature of each thermostat to be consistent;

[0034] Set the unit humidity adjustment value;

[0035] Let the minimum humidity be H min ;

[0036] Adjust the humidity of the incubator to H min , H min +1×unit humidity adjustment value...H min +(N / 2)×unit humidity adjustment value, where N represents the total number of standard gas samples;

[0037] Use the NDIR sensor to measure the concentration of the standard gas at each humidity to be measured, and record the humidity and the corresponding measured concentration;

[0038] Plot the humidity as the horizontal axis and the measured concentration as the vertical axis to obtain a scatter plot of concentration versus humidity;

[0039] The scatter plot was fitted using linear regression to obtain the linear relationship between concentration and humidity;

[0040] Different humidity ranges are respectively recorded as the first humidity range, the second humidity range, ... the Kth humidity range;

[0041] Assume that the linear relationship of the first humidity range is C1=x1+y1×H1, where H1 represents the difference between the humidity within the first humidity range and the reference humidity within the first humidity range;

[0042] Substitute the humidity value and the concentration value corresponding to the humidity value in the first humidity range into the linear relationship formula of the first humidity range to calculate the x1 value and the y1 value, wherein the y1 value is the humidity compensation value of the first humidity range;

[0043] Assume that the linear relationship of the second humidity range is C2=x2+y2×H2, where H2 represents the difference between the humidity within the second humidity range and the reference humidity within the second humidity range;

[0044] Substitute the humidity value and the concentration value corresponding to the humidity value within the second humidity range into the linear relationship formula of the second humidity range to calculate the x2 value and the y2 value, wherein the y2 value is the humidity compensation value of the second humidity range;

[0045] The linear relationship of the third humidity range...the linear relationship of the Kth humidity range is set in sequence to obtain the humidity compensation value under the corresponding humidity range.

[0046] Optionally, the use of a mixed gas collection device to collect the gas in the space to be measured specifically includes:

[0047] Obtain the length of each intake pipe of the mixed gas collecting device;

[0048] Obtain the temperature and humidity of the space to be measured and record them as the first measured temperature and the first measured humidity;

[0049] Assume that the velocity of the gas in the intake pipe is a constant value v;

[0050] Calculate the time T required for gas to pass through intake pipes of different lengths Q ,T Q =L Q / v, where L Q is the length of the Qth intake pipe;

[0051] Compare the length of each intake pipe, using the longest intake pipe as the benchmark;

[0052] Calculate the delayed opening time of the remaining intake pipes relative to the longest intake pipe: ΔT Q =T max -T Q , where T max T is the travel time of the gas in the longest intake pipe, Q is the travel time of the Qth tube, ΔT Q is the delayed opening time of the Qth tube;

[0053] Install a timer for each intake pipe valve and air extractor and set the opening time;

[0054] Set the timer of the longest intake pipe to start at t=0;

[0055] Set the timers of the remaining intake pipes according to the calculated delay time ΔT Q Set up in sequence;

[0056] Start the timers of all intake pipes at the same time;

[0057] The timer opens the valves and vacuum pumps of each air inlet pipe in sequence according to the set time, so that the gas flows into the container in the same time;

[0058] The gas to be tested collected in the container is recorded as the first mixed gas to be tested.

[0059] Optionally, the use of a monomer gas collection device to collect the gas in the space to be measured specifically includes:

[0060] Obtain the number of inlet pipes of the mixed gas collecting device;

[0061] Obtaining the heights of the air inlets of each air inlet pipe of the mixed gas collection device;

[0062] The same number of single gas collecting devices as the intake pipes of the mixed gas collecting device are provided;

[0063] The air inlets of the monomer gas collection device are respectively arranged at different heights, and the different heights are the different heights at which the air inlets of the air inlet pipes of the mixed gas collection device are arranged;

[0064] Obtain the temperature and humidity of the space to be measured and record them as the second measured temperature and the second measured humidity;

[0065] The gases collected by the monomer gas collecting device are named as the first height test gas, the second height test gas, ... the Qth height test gas in order from top to bottom according to the height at which the monomer gas collecting device is set;

[0066] The collected gases are mixed into the same container, and the mixed gas is recorded as the second mixed gas to be tested.

[0067] Optionally, the calculation of the concentration of the gas to be measured in the space target by the compensation method specifically includes:

[0068] Obtaining a temperature range and a humidity range in which a first measured temperature and a first measured humidity are located;

[0069] Obtain the reference temperature and reference humidity within the temperature range and humidity range;

[0070] Obtain the temperature compensation value and humidity compensation value within the temperature range and humidity range;

[0071] Using an NDIR sensor to measure the original concentration of the first mixed gas to be measured;

[0072] Use temperature compensation and humidity compensation to compensate the measurement result of the first mixed gas to be measured. The compensation formula is: C 第一待测混合气体 =C 第一待测混合气体的原始浓度 +K T ×(T 第一测量温度 -T 基准温度 )+K H ×(H 第一测量湿度 -H 基准湿度 ), where K T is the temperature compensation value, K H is the humidity compensation value;

[0073] The compensated gas concentration obtained by using the compensation formula is recorded as the first measured gas compensation concentration.

[0074] Optionally, the calculation of the concentration of the gas to be measured in the space target by the compensation method specifically includes:

[0075] Obtaining a temperature range and a humidity range in which the second measured temperature and the second measured humidity are located;

[0076] Obtain the reference temperature and reference humidity within the temperature range and humidity range;

[0077] Obtain the temperature compensation value and humidity compensation value within the temperature range and humidity range;

[0078] Using the NDIR sensor to measure the original concentration of the second mixed gas to be tested;

[0079] Use temperature compensation and humidity compensation to compensate the measurement result of the second mixed gas to be measured. The compensation formula is: C 第二待测混合气体 =C 第二待测混合气体的原始浓度 +K T ×(T 第二测量温度 -T 基准温度 )+K H ×(H 第二测量湿度 -H 基准湿度 ), where K T is the temperature compensation value, K H is the humidity compensation value;

[0080] The compensated gas concentration is obtained by using the compensation formula and recorded as the compensated concentration of the second gas to be measured;

[0081] The average value of the first gas compensation concentration and the second gas compensation concentration is calculated and recorded as the target gas concentration in the measured space.

[0082] The present invention has the following beneficial effects:

[0083] 1. Selecting standard gas samples of known concentration is the basis of the experiment. This step ensures the accuracy and reliability of subsequent measurement data. The same container volume can ensure that each gas sample is tested at the same volume, eliminating the error caused by different container volumes. Marking serial numbers can facilitate the operation and recording of subsequent experimental steps to avoid confusion and errors. The constant temperature box provides a stable and controllable environment, which can eliminate the influence of external environmental factors on the experimental results. By controlling the temperature and humidity, it can ensure that the experiment is carried out under the set conditions, further improving the accuracy of the experimental results.

[0084] 2. By setting the temperature range and humidity range with an upper and lower floating range of 15%, the measurement conditions under different temperature and humidity conditions can be simulated, and the influence of temperature and humidity changes on gas concentration measurement and compensation methods can be explored. This operation helps to find the best temperature and humidity compensation strategy and improve the accuracy and stability of the measurement results. At the same time, the setting of multiple reference points also provides rich data support for the analysis and promotion of experimental results.

[0085] 3. The use of a mixed gas collection device can comprehensively and evenly collect gas samples in the measurement space; multiple inlet pipes with the same diameter and inlets set at different heights can ensure the representativeness of the gas sample and avoid measurement errors caused by uneven distribution of gas in the space; the setting of the inlet valve and the vacuum pump can control the inlet flow rate and ensure the stability of the gas sample; connecting the outlet of the inlet pipe to the same gas collection container can mix gas samples at different heights to obtain a more uniform mixed gas to be tested; this operation helps to improve the accuracy and representativeness of the measurement results and provide reliable samples for subsequent gas concentration determination.

[0086] 4. The design of a single air inlet pipe can collect gas at a specific point. The settings of the air inlet valve and the air pump can control the air inlet flow rate to ensure the stability and representativeness of the gas sample. Connecting gas collection containers with the same volume can ensure the consistency of the sample volume, which is convenient for subsequent analysis and measurement. This operation can provide accurate samples when gas concentration data at a specific point is required, meet various measurement needs, and improve the flexibility and applicability of the experiment.

[0087] 5. By calculating the target gas concentration through the compensation method, the measurement error caused by temperature and humidity changes can be corrected to improve the accuracy of the measurement results. The compensation method uses the previously obtained temperature and humidity compensation values ​​to correct the actual measurement data, making the final gas concentration result more accurate. This method combines the compensation data obtained in the experiment with the actual measurement data, fully considers the influence of environmental factors, and effectively improves the reliability and repeatability of the measurement results.

[0088] 6. Adjusting the humidity of each constant temperature box to be consistent can eliminate the influence of humidity variables and ensure that the experimental results are only affected by temperature changes. Unifying humidity conditions can improve the comparability and accuracy of experimental results and make the measurement data more scientific; setting the unit temperature adjustment value can ensure the control accuracy and consistency of temperature changes; setting the minimum temperature Tmin can clarify the starting temperature point of the experiment and provide a benchmark for the entire experimental design; using temperature as the horizontal axis and measured concentration as the vertical axis to draw a graph can intuitively show the trend of concentration changes with temperature; dividing different temperature ranges into multiple intervals can refine the study of temperature compensation and ensure that the compensation value of each temperature interval is more accurate; setting the linear relationship of the first temperature range can clarify the specific form of gas concentration changes with temperature in this temperature range; by calculating the regression coefficient, the temperature compensation strategy can be optimized to improve the accuracy and applicability of the compensation model; setting the linear relationship of each temperature range in turn can comprehensively and systematically analyze the law of gas concentration changes with temperature in different temperature ranges.

[0089] 7. Adjusting the temperature of each thermostat to be consistent can eliminate the influence of temperature variables and ensure that the experimental results are only affected by humidity changes. Unifying temperature conditions can improve the comparability and accuracy of experimental results and make the measurement data more scientific. Setting the unit humidity adjustment value can ensure the control accuracy and consistency of humidity changes. Setting the minimum humidity Hmin can clarify the starting humidity point of the experiment and provide a benchmark for the entire experimental design. Plotting with humidity as the horizontal axis and measured concentration as the vertical axis can intuitively show the trend of concentration changes with humidity. Dividing different humidity ranges into multiple intervals can refine the research on humidity compensation and ensure that the compensation value of each humidity interval is more accurate. Setting the linear relationship of the first humidity range can clarify the specific form of gas concentration changes with humidity in this humidity range. By calculating the regression coefficient, the humidity compensation strategy can be optimized to improve the accuracy and applicability of the compensation model. Setting the linear relationship of each humidity range in turn can comprehensively and systematically analyze the law of gas concentration changes with humidity in different humidity intervals.

[0090] 8. Obtaining the length of each intake pipe is the basis for accurate time calculation and flow control; different intake pipe lengths will result in different gas passage times, thus affecting the composition and concentration consistency of the mixed gas; by measuring the length of each intake pipe, data support can be provided for subsequent delay time calculations to ensure that the gases in each intake pipe arrive at the collection container at the same time; this operation can reduce the measurement error caused by differences in intake pipe lengths, improve the accuracy and consistency of mixed gas collection, and provide reliable samples for subsequent gas analysis; by calculating the delayed opening time, the opening time of each intake pipe can be accurately controlled to ensure that the gases arrive at the collection container at the same time.

[0091] 9. By knowing the number of intake pipes, the experiment can be reasonably arranged and designed to ensure that all gas samples at different heights and positions can be effectively collected; setting up the same number of single gas collection devices can ensure that each intake height has a corresponding independent gas sample collection; this can effectively avoid the interference of gases at different heights when collecting mixed gases, and improve the independence and accuracy of gas samples; through mixed gas samples, the average composition and concentration of the gas in the measurement space can be fully reflected. This can reduce the measurement error caused by the difference in gas composition at individual heights and improve the representativeness and accuracy of the measurement results.

[0092] 10. Obtaining the range of the first measured temperature and humidity can clarify the specific conditions of the measurement environment; knowing the range of temperature and humidity will help to select appropriate reference temperature and humidity to ensure the accuracy and scientificity of the compensation calculation; obtaining the reference temperature and reference humidity can provide a standard reference for the calculation in the compensation formula; obtaining the temperature compensation value and the humidity compensation value can provide specific numerical parameters for the compensation calculation; these compensation values ​​are obtained based on the law of gas concentration changes under different environmental conditions. By using these compensation values, the measurement errors caused by temperature and humidity changes can be effectively corrected; using NDIR sensors to measure gas concentrations can obtain high-precision original measurement data; using compensation formulas to compensate for measurement results can effectively correct errors caused by temperature and humidity changes; through compensation formulas, the impact of environmental conditions can be quantified, and measurement results can be accurately adjusted to ensure the accuracy and stability of gas concentration data.

[0093] 11. Obtaining the range of the second measured temperature and humidity can accurately describe the environmental conditions during the second measurement; by understanding the range of temperature and humidity, appropriate reference values ​​can be selected for compensation calculations to ensure the accuracy and scientificity of the calculations; by clarifying the reference temperature and humidity, the measurement errors caused by changes in environmental conditions can be effectively corrected to improve the stability and consistency of the data; obtaining temperature and humidity compensation values ​​can provide specific numerical parameters for compensation calculations; these compensation values ​​are derived based on the law of changes in gas concentration under different environmental conditions. By using these compensation values, measurement errors can be effectively corrected to ensure the accuracy and stability of the data; using NDIR sensors to measure gas concentrations can obtain high-precision original measurement data; using compensation formulas to compensate for measurement results can effectively correct errors caused by changes in temperature and humidity; taking the average of two compensated concentrations can effectively eliminate accidental errors in single measurements and improve the accuracy and representativeness of data. BRIEF DESCRIPTION OF THE DRAWINGS

[0094] Figure 1 It is a schematic diagram of the mixed gas collecting device of the present invention. DETAILED DESCRIPTION

[0095] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0096] Example, see Figure 1 , a gas concentration detection method based on NDIR technology, comprising:

[0097] Select a standard gas sample with a known concentration of the gas to be tested;

[0098] Place the standard gas samples in containers of the same volume and mark them with serial numbers, namely the first standard gas sample, the second standard gas sample, and the Nth standard gas sample. The volumes of these containers should be consistent, usually standard gas bottles commonly used in laboratories, to ensure that each gas sample is tested under the same volume conditions;

[0099] The containers containing the standard gas samples are placed in a thermostatic box capable of controlling temperature and humidity;

[0100] Set multiple reference temperature points, and set a temperature range with an upper and lower floating range of 15% based on the reference temperature points;

[0101] Set multiple reference humidity points, and set a humidity range with an upper and lower floating range of 15% based on the reference humidity points;

[0102] While keeping the humidity constant, measure the compensation value of temperature in different temperature ranges;

[0103] When keeping the temperature constant, measure the compensation value of humidity in different humidity ranges;

[0104] A mixed gas collection device is used to collect the gas in the space to be measured, which is recorded as the mixed gas to be measured. The mixed gas collection device includes multiple inlet pipes of the same diameter, the inlets are set at different heights, the inlet valves and the air pump are set at the inlet, and the outlet of the inlet pipe is connected to the same gas collection container. The mixed gas collection device can comprehensively collect the gas in the entire measurement space through the inlets set at different heights to ensure the representativeness and uniformity of the sampling. The configuration of the inlet valve and the air pump allows the intake volume and flow rate to be accurately controlled;

[0105] A monomer gas collecting device is used to collect the gas in the space to be measured, wherein the monomer gas collecting device comprises an air inlet pipe, a valve and a vacuum pump are arranged at the air inlet, and the outlet of the air inlet pipe is connected to a gas collection container with the same volume;

[0106] The compensation method is used to calculate the concentration of the space target gas to be measured. According to the previously measured temperature and humidity compensation values, the actual measured gas concentration is corrected to obtain the final space target gas concentration.

[0107] Selecting standard gas samples of known concentration is the basis of the experiment. This step ensures the accuracy and reliability of subsequent measurement data. The same container volume can ensure that each gas sample is experimented at the same volume, eliminating errors caused by different container volumes. Labeling with serial numbers can facilitate the operation and recording of subsequent experimental steps and avoid confusion and errors. The constant temperature box provides a stable and controllable environment that can eliminate the influence of external environmental factors on the experimental results. By controlling the temperature and humidity, it can ensure that the experiment is carried out under the set conditions, further improving the accuracy of the experimental results.

[0108] By setting the temperature and humidity ranges with an upper and lower floating range of 15%, we can simulate the measurement conditions under different temperature and humidity conditions, and explore the impact of temperature and humidity changes on gas concentration measurement and compensation methods. This operation helps to find the best temperature and humidity compensation strategy and improve the accuracy and stability of the measurement results. At the same time, the setting of multiple reference points also provides rich data support for the analysis and promotion of experimental results.

[0109] The use of a mixed gas collection device can comprehensively and evenly collect gas samples in the measurement space; multiple inlet pipes with the same diameter and inlets set at different heights can ensure the representativeness of the gas sample and avoid measurement errors caused by uneven distribution of gas in the space; the setting of the inlet valve and the vacuum fan can control the inlet flow rate and ensure the stability of the gas sample; connecting the outlet of the inlet pipe to the same gas collection container can mix gas samples at different heights to obtain a more evenly mixed gas to be tested; this operation helps to improve the accuracy and representativeness of the measurement results and provide reliable samples for subsequent gas concentration measurements.

[0110] The design of a single inlet pipe can collect gas at a specific point. The settings of the inlet valve and the air pump can control the inlet flow rate to ensure the stability and representativeness of the gas sample. Connecting gas collection containers with the same volume can ensure the consistency of the sample volume, which is convenient for subsequent analysis and measurement. This operation can provide accurate samples when gas concentration data at a specific point is required, meet various measurement needs, and improve the flexibility and applicability of the experiment.

[0111] By calculating the target gas concentration through the compensation method, the measurement error caused by temperature and humidity changes can be corrected to improve the accuracy of the measurement results; the compensation method uses the previously obtained temperature and humidity compensation values ​​to correct the actual measurement data, making the final gas concentration result more accurate; this method combines the compensation data obtained in the experiment with the actual measurement data, fully considers the influence of environmental factors, and effectively improves the reliability and repeatability of the measurement results.

[0112] When the humidity is kept constant, the compensation value of the temperature in different temperature ranges is measured, specifically including:

[0113] Select half of the number of the constant temperature boxes as samples for measuring temperature compensation values ​​in different temperature ranges;

[0114] Adjust the humidity of each incubator to be consistent;

[0115] Set the unit temperature adjustment value;

[0116] Let the minimum temperature be T min ;

[0117] Adjust the temperature of the thermostat box to T min , T min +1×unit temperature adjustment value...T min +(N / 2)×unit temperature adjustment value, where N represents the total number of standard gas samples;

[0118] Use the NDIR sensor to measure the concentration of the standard gas at each temperature to be tested, and record the temperature and the corresponding measured concentration;

[0119] With temperature as the horizontal axis and measured concentration as the vertical axis, a scatter plot of concentration versus temperature is obtained. This allows for intuitive observation of the effect of temperature on the measured gas concentration value, facilitating subsequent analysis.

[0120] Use linear regression to fit the scatter plot and get the linear relationship between concentration and temperature. Linear regression is a statistical method that fits data points by the least squares method to get a best fit straight line that describes the relationship between concentration and temperature.

[0121] The different temperature ranges are respectively recorded as a first temperature range, a second temperature range, ... an Mth temperature range;

[0122] Assume that the linear relationship of the first temperature range is C1=a1+b1×T1, where T1 represents the difference between the temperature in the first temperature range and the reference temperature in the first temperature range;

[0123] Substituting the temperature value and the concentration value corresponding to the temperature value in the first temperature range into the linear relationship formula of the first temperature range to calculate the a1 value and the b1 value, wherein the b1 value is the temperature compensation value of the first temperature range;

[0124] Assume that the linear relationship of the second temperature range is C2=a2+b2×T2, where T2 represents the difference between the temperature in the second temperature range and the reference temperature in the second temperature range;

[0125] Substituting the temperature value and the concentration value corresponding to the temperature value in the second temperature range into the linear relationship formula of the second temperature range to calculate the a2 value and the b2 value, wherein the b2 value is the temperature compensation value of the second temperature range;

[0126] The linear relationship of the third temperature range, ... the linear relationship of the Mth temperature range are sequentially set to obtain the temperature compensation value in the corresponding temperature range.

[0127] Adjusting the humidity of each constant temperature box to be consistent can eliminate the influence of humidity variables and ensure that the experimental results are only affected by temperature changes. Unifying humidity conditions can improve the comparability and accuracy of experimental results and make the measurement data more scientific. Setting the unit temperature adjustment value can ensure the control accuracy and consistency of temperature changes. Setting the minimum temperature Tmin can clarify the starting temperature point of the experiment and provide a benchmark for the entire experimental design. Plotting with temperature as the horizontal axis and measured concentration as the vertical axis can intuitively show the trend of concentration changes with temperature. Dividing different temperature ranges into multiple intervals can refine the study of temperature compensation and ensure that the compensation value of each temperature interval is more accurate. Setting the linear relationship of the first temperature range can clarify the specific form of gas concentration changes with temperature within this temperature range. By calculating the regression coefficient, the temperature compensation strategy can be optimized to improve the accuracy and applicability of the compensation model. Setting the linear relationship of each temperature range in turn can comprehensively and systematically analyze the law of gas concentration changes with temperature in different temperature ranges.

[0128] When the temperature is kept constant, the compensation value of humidity in different humidity ranges is measured, specifically including:

[0129] Select half of the number of the constant temperature boxes as samples for measuring humidity compensation values ​​in different humidity ranges;

[0130] Adjust the temperature of each thermostat to be consistent;

[0131] Set the unit humidity adjustment value;

[0132] Let the minimum humidity be H min ;

[0133] Adjust the humidity of the incubator to H min , H min +1×unit humidity adjustment value...H min +(N / 2)×unit humidity adjustment value;

[0134] Use the NDIR sensor to measure the concentration of the standard gas at each humidity to be measured, and record the humidity and the corresponding measured concentration;

[0135] Plot the humidity as the horizontal axis and the measured concentration as the vertical axis to obtain a scatter plot of concentration versus humidity;

[0136] The scatter plot was fitted using linear regression to obtain the linear relationship between concentration and humidity;

[0137] Different humidity ranges are respectively recorded as the first humidity range, the second humidity range, ... the Kth humidity range;

[0138] Assume that the linear relationship of the first humidity range is C1=x1+y1×H1, where H1 represents the difference between the humidity within the first humidity range and the reference humidity within the first humidity range;

[0139] Substitute the humidity value and the concentration value corresponding to the humidity value in the first humidity range into the linear relationship formula of the first humidity range to calculate the x1 value and the y1 value, wherein the y1 value is the humidity compensation value of the first humidity range;

[0140] Assume that the linear relationship of the second humidity range is C2=x2+y2×H2, where H2 represents the difference between the humidity within the second humidity range and the reference humidity within the second humidity range;

[0141] Substitute the humidity value and the concentration value corresponding to the humidity value within the second humidity range into the linear relationship formula of the second humidity range to calculate the x2 value and the y2 value, wherein the y2 value is the humidity compensation value of the second humidity range;

[0142] The linear relationship of the third humidity range...the linear relationship of the Kth humidity range is set in sequence to obtain the humidity compensation value under the corresponding humidity range.

[0143] Adjusting the temperature of each thermostat to be consistent can eliminate the influence of temperature variables and ensure that the experimental results are only affected by humidity changes. Unifying temperature conditions can improve the comparability and accuracy of experimental results and make the measurement data more scientific. Setting the unit humidity adjustment value can ensure the control accuracy and consistency of humidity changes. Setting the minimum humidity Hmin can clarify the starting humidity point of the experiment and provide a benchmark for the entire experimental design. Plotting with humidity as the horizontal axis and measured concentration as the vertical axis can intuitively show the trend of concentration changes with humidity. Dividing different humidity ranges into multiple intervals can refine the research on humidity compensation and ensure that the compensation value of each humidity interval is more accurate. Setting the linear relationship of the first humidity range can clarify the specific form of gas concentration changes with humidity in this humidity range. By calculating the regression coefficient, the humidity compensation strategy can be optimized to improve the accuracy and applicability of the compensation model. Setting the linear relationship of each humidity range in turn can comprehensively and systematically analyze the law of gas concentration changes with humidity in different humidity intervals.

[0144] The method of using a mixed gas collecting device to collect the gas in the space to be measured specifically includes:

[0145] Obtain the length of each intake pipe of the mixed gas collecting device;

[0146] Obtain the temperature and humidity of the space to be measured and record them as the first measured temperature and the first measured humidity;

[0147] Assume that the velocity of the gas in the intake pipe is a constant value v;

[0148] Calculate the time T required for gas to pass through intake pipes of different lengths Q ,T Q =L Q / v, where L Q is the length of the Qth intake pipe;

[0149] Compare the length of each intake pipe, using the longest intake pipe as the benchmark;

[0150] Calculate the delayed opening time of the remaining intake pipes relative to the longest intake pipe: ΔT Q =T max -T Q , where T max T is the travel time of the gas in the longest intake pipe, Q is the travel time of the Qth tube, ΔT Q is the delayed opening time of the Qth tube;

[0151] Install a timer for each intake pipe valve and air extractor and set the opening time;

[0152] Set the timer of the longest intake pipe to start at t=0;

[0153] Set the timers of the remaining intake pipes according to the calculated delay time ΔT Q Set up in sequence;

[0154] Start the timers of all intake pipes at the same time;

[0155] The timer opens the valves and vacuum pumps of each air inlet pipe in sequence according to the set time, so that the gas flows into the container in the same time;

[0156] The gas to be tested collected in the container is recorded as the first mixed gas to be tested.

[0157] Obtaining the length of each intake pipe is the basis for accurate time calculation and flow control; different intake pipe lengths will result in different gas passage times, thus affecting the composition and concentration consistency of the mixed gas; by measuring the length of each intake pipe, data support can be provided for subsequent delay time calculations to ensure that the gases in each intake pipe arrive at the collection container at the same time; this operation can reduce the measurement error caused by differences in intake pipe lengths, improve the accuracy and consistency of mixed gas collection, and provide reliable samples for subsequent gas analysis; calculating the delayed opening time can accurately control the opening time of each intake pipe to ensure that the gases arrive at the collection container at the same time.

[0158] The method of using a monomer gas collection device to collect the gas in the space to be measured specifically includes:

[0159] Obtain the number of inlet pipes of the mixed gas collecting device;

[0160] Obtaining the heights of the air inlets of each air inlet pipe of the mixed gas collection device;

[0161] The same number of single gas collecting devices as the intake pipes of the mixed gas collecting device are provided;

[0162] The air inlets of the monomer gas collection device are respectively arranged at different heights, and the different heights are the different heights at which the air inlets of the air inlet pipes of the mixed gas collection device are arranged;

[0163] Obtain the temperature and humidity of the space to be measured and record them as the second measured temperature and the second measured humidity;

[0164] The gases collected by the monomer gas collecting device are named as the first height test gas, the second height test gas, ... the Qth height test gas in order from top to bottom according to the height at which the monomer gas collecting device is set;

[0165] The collected gases are mixed into the same container, and the mixed gas is recorded as the second mixed gas to be tested.

[0166] By knowing the number of intake pipes, the experiment can be reasonably arranged and designed to ensure that all gas samples at different heights and positions can be effectively collected; setting up the same number of single gas collection devices can ensure that each intake height has a corresponding independent gas sample collection; this can effectively avoid the interference of gases at different heights when collecting mixed gases, and improve the independence and accuracy of gas samples; through mixed gas samples, the average composition and concentration of the gas in the measurement space can be fully reflected. This can reduce the measurement error caused by the difference in gas composition at individual heights and improve the representativeness and accuracy of the measurement results.

[0167] The method of calculating the concentration of the gas to be measured in the space target by the compensation method specifically includes:

[0168] Obtaining a temperature range and a humidity range in which a first measured temperature and a first measured humidity are located;

[0169] Obtain the reference temperature and reference humidity within the temperature range and humidity range;

[0170] Obtain the temperature compensation value and humidity compensation value within the temperature range and humidity range;

[0171] Using an NDIR sensor to measure the original concentration of the first mixed gas to be measured;

[0172] Use temperature compensation and humidity compensation to compensate the measurement result of the first mixed gas to be measured. The compensation formula is: C 第一待测混合气体 =C 第一待测混合气体的原始浓度 +K T ×(T 第一测量温度 -T 基准温度 )+K H ×(H 第一测量湿度 -H 基准湿度 ), where K T is the temperature compensation value, K H is the humidity compensation value;

[0173] The compensated gas concentration obtained by using the compensation formula is recorded as the first measured gas compensation concentration.

[0174] Obtaining the range of the first measured temperature and humidity can clarify the specific conditions of the measurement environment; knowing the range of temperature and humidity is helpful to select appropriate reference temperature and humidity to ensure the accuracy and scientificity of the compensation calculation; obtaining the reference temperature and reference humidity can provide a standard reference for the calculation in the compensation formula; obtaining the temperature compensation value and the humidity compensation value can provide specific numerical parameters for the compensation calculation; these compensation values ​​are obtained according to the law of gas concentration changes under different environmental conditions. By using these compensation values, the measurement errors caused by temperature and humidity changes can be effectively corrected; using the NDIR sensor to measure gas concentration can obtain high-precision original measurement data; using the compensation formula to compensate the measurement results can effectively correct the errors caused by temperature and humidity changes; through the compensation formula, the impact of environmental conditions can be quantified, the measurement results can be accurately adjusted, and the accuracy and stability of gas concentration data can be ensured.

[0175] The method of calculating the concentration of the gas to be measured in the space target by the compensation method specifically includes:

[0176] Obtaining a temperature range and a humidity range in which the second measured temperature and the second measured humidity are located;

[0177] Obtain the reference temperature and reference humidity within the temperature range and humidity range;

[0178] Obtain the temperature compensation value and humidity compensation value within the temperature range and humidity range;

[0179] Using the NDIR sensor to measure the original concentration of the second mixed gas to be tested;

[0180] Use temperature compensation and humidity compensation to compensate the measurement result of the second mixed gas to be measured. The compensation formula is: C 第二待测混合气体 =C 第二待测混合气体的原始浓度 +K T ×(T 第二测量温度 -T 基准温度 )+K H ×(H 第二测量湿度 -H 基准湿度 ), where K T is the temperature compensation value, K H is the humidity compensation value;

[0181] The compensated gas concentration is obtained by using the compensation formula and recorded as the compensated concentration of the second gas to be measured;

[0182] The average value of the first gas compensation concentration and the second gas compensation concentration is calculated and recorded as the target gas concentration in the measured space.

[0183] Obtaining the range of the second measured temperature and humidity can accurately describe the environmental conditions during the second measurement; by understanding the range of temperature and humidity, appropriate reference values ​​can be selected for compensation calculations to ensure the accuracy and scientificity of the calculations; by clarifying the reference temperature and humidity, measurement errors caused by changes in environmental conditions can be effectively corrected to improve the stability and consistency of the data; obtaining temperature and humidity compensation values ​​can provide specific numerical parameters for compensation calculations; these compensation values ​​are derived based on the law of changes in gas concentration under different environmental conditions. By using these compensation values, measurement errors can be effectively corrected to ensure the accuracy and stability of the data; using NDIR sensors to measure gas concentrations can obtain high-precision original measurement data; using compensation formulas to compensate for measurement results can effectively correct errors caused by changes in temperature and humidity; taking the average of two compensated concentrations can effectively eliminate accidental errors in single measurements and improve the accuracy and representativeness of data.

[0184] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0185] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A gas concentration detection method based on NDIR technology, characterized in that: include: Select a standard gas sample with a known concentration of the gas to be tested; Place the standard gas samples in containers of the same volume and label them with serial numbers, namely the first standard gas sample, the second standard gas sample, and so on. The containers containing the standard gas samples are placed in a thermostatic box with controlled temperature and humidity; Set multiple reference temperature points, and set a temperature range with an upper and lower floating range of 15% based on the reference temperature points; Set multiple reference humidity points, and set a humidity range with an upper and lower floating range of 15% based on the reference humidity points; While keeping the humidity constant, measure the compensation value of temperature in different temperature ranges; The compensation value of measuring the temperature in different temperature ranges while keeping the humidity constant specifically includes: Select half of the number of the constant temperature boxes as samples for measuring temperature compensation values ​​in different temperature ranges; Adjust the humidity of each incubator to be consistent; Set the unit temperature adjustment value; Let the minimum temperature be T min ; Adjust the temperature of the thermostat box to T min , T min +1×unit temperature adjustment value...T min +(N / 2)×unit temperature adjustment value, where N represents the total number of standard gas samples; Use the NDIR sensor to measure the concentration of the standard gas at each temperature to be tested, and record the temperature and the corresponding measured concentration; Plot the temperature as the horizontal axis and the measured concentration as the vertical axis to obtain a scatter plot of concentration versus temperature; The scatter plot was fitted using linear regression to obtain a linear relationship between concentration and temperature; The different temperature ranges are respectively recorded as a first temperature range, a second temperature range, ... an Mth temperature range; Assume that the linear relationship of the first temperature range is C1=a1+b1×T1, where T1 represents the difference between the temperature in the first temperature range and the reference temperature in the first temperature range; Substituting the temperature value and the concentration value corresponding to the temperature value in the first temperature range into the linear relationship formula of the first temperature range to calculate the a1 value and the b1 value, wherein the b1 value is the temperature compensation value of the first temperature range; Assume that the linear relationship of the second temperature range is C2=a2+b2×T2, where T2 represents the difference between the temperature in the second temperature range and the reference temperature in the second temperature range; Substituting the temperature value and the concentration value corresponding to the temperature value in the second temperature range into the linear relationship formula of the second temperature range to calculate the a2 value and the b2 value, wherein the b2 value is the temperature compensation value of the second temperature range; The linear relationship of the third temperature range, the linear relationship of the Mth temperature range are sequentially set to obtain the temperature compensation value in the corresponding temperature range; When keeping the temperature constant, measure the compensation value of humidity in different humidity ranges; The method of measuring the compensation value of humidity in different humidity ranges while maintaining a constant temperature specifically includes: Select half of the number of the constant temperature boxes as samples for measuring humidity compensation values ​​in different humidity ranges; Adjust the temperature of each thermostat to be consistent; Set the unit humidity adjustment value; Let the minimum humidity be H min ; Adjust the humidity of the incubator to H min , H min +1×unit humidity adjustment value...H min +(N / 2)×unit humidity adjustment value; Use the NDIR sensor to measure the concentration of the standard gas at each humidity to be measured, and record the humidity and the corresponding measured concentration; Plot the humidity as the horizontal axis and the measured concentration as the vertical axis to obtain a scatter plot of concentration versus humidity; The scatter plot was fitted using linear regression to obtain the linear relationship between concentration and humidity; Different humidity ranges are respectively recorded as the first humidity range, the second humidity range, ... the Kth humidity range; Assume that the linear relationship of the first humidity range is C1=x1+y1×H1, where H1 represents the difference between the humidity within the first humidity range and the reference humidity within the first humidity range; Substitute the humidity value and the concentration value corresponding to the humidity value in the first humidity range into the linear relationship formula of the first humidity range to calculate the x1 value and the y1 value, wherein the y1 value is the humidity compensation value of the first humidity range; Assume that the linear relationship of the second humidity range is C2=x2+y2×H2, where H2 represents the difference between the humidity within the second humidity range and the reference humidity within the second humidity range; Substitute the humidity value and the concentration value corresponding to the humidity value within the second humidity range into the linear relationship formula of the second humidity range to calculate the x2 value and the y2 value, wherein the y2 value is the humidity compensation value of the second humidity range; The linear relationship of the third humidity range...the linear relationship of the Kth humidity range is sequentially set to obtain the humidity compensation value under the corresponding humidity range; A mixed gas collecting device is used to collect the gas in the space to be measured, which is recorded as the mixed gas to be measured. The mixed gas collecting device includes a plurality of air inlet pipes with the same diameter, the air inlets are arranged at different heights, the air inlet valves and the air pump are arranged at the air inlet, and the air outlets of the air inlet pipes are connected to the same gas collection container; The use of a mixed gas collection device to collect the gas in the space to be measured specifically includes: Obtain the length of each intake pipe of the mixed gas collecting device; Obtain the temperature and humidity of the space to be measured and record them as the first measured temperature and the first measured humidity; Assume that the velocity of the gas in the intake pipe is a constant value v; Calculate the time T required for gas to pass through intake pipes of different lengths Q ,T Q =L Q / v, where L Q is the length of the Qth intake pipe; Compare the length of each intake pipe, using the longest intake pipe as the benchmark; Calculate the delayed opening time of the remaining intake pipes relative to the longest intake pipe: ΔT Q =T max -T Q , where T max T is the travel time of the gas in the longest intake pipe, Q is the travel time of the Qth tube, ΔT Q is the delayed opening time of the Qth tube; Install a timer for each intake pipe valve and air extractor and set the opening time; Set the timer of the longest intake pipe to start at t=0; Set the timers of the remaining intake pipes according to the calculated delay time ΔT Q Set up in sequence; Start the timers of all intake pipes at the same time; The timer opens the valves and vacuum pumps of each air inlet pipe in sequence according to the set time, so that the gas flows into the container in the same time; The gas to be tested collected in the container is recorded as the first mixed gas to be tested; A monomer gas collecting device is used to collect the gas in the space to be measured, wherein the monomer gas collecting device comprises an air inlet pipe, a valve and a vacuum pump are arranged at the air inlet, and the outlet of the air inlet pipe is connected to a gas collection container with the same volume; The use of a monomer gas collection device to collect the gas in the space to be measured specifically includes: Obtain the number of intake pipes of the mixed gas collecting device; Obtaining the heights of the air inlets of each air inlet pipe of the mixed gas collection device; The same number of single gas collecting devices as the intake pipes of the mixed gas collecting device are provided; The air inlets of the monomer gas collection device are respectively arranged at different heights, and the different heights are the different heights at which the air inlets of the air inlet pipes of the mixed gas collection device are arranged; Obtain the temperature and humidity of the space to be measured and record them as the second measured temperature and the second measured humidity; The gases collected by the monomer gas collecting device are named as the first height test gas, the second height test gas, ... the Qth height test gas in order from top to bottom according to the height at which the monomer gas collecting device is set; Mix the collected gases into the same container, and record the mixed gas as the second mixed gas to be tested; The concentration of the gas to be measured in the space target is calculated by the compensation method; The method of calculating the concentration of the gas to be measured in the space target by the compensation method specifically includes: Obtaining a temperature range and a humidity range in which a first measured temperature and a first measured humidity are located; Obtain the reference temperature and reference humidity within the temperature range and humidity range; Obtain the temperature compensation value and humidity compensation value within the temperature range and humidity range; Using an NDIR sensor to measure the original concentration of the first mixed gas to be tested; Use temperature compensation and humidity compensation to compensate the measurement result of the first mixed gas to be measured. The compensation formula is: C 第一待测混合气体 =C 第一待测混合气体的原始浓度 +K T ×(T 第一测量温度 -T 基准温度 )+K H ×(H 第一测量湿度 -H 基准湿度 ), where K T is the temperature compensation value, K H is the humidity compensation value; The compensated gas concentration is obtained by using the compensation formula and recorded as the first measured gas compensation concentration; Obtaining a temperature range and a humidity range in which the second measured temperature and the second measured humidity are located; Obtain the reference temperature and reference humidity within the temperature range and humidity range; Obtain the temperature compensation value and humidity compensation value within the temperature range and humidity range; Using the NDIR sensor to measure the original concentration of the second mixed gas to be tested; Use temperature compensation and humidity compensation to compensate the measurement result of the second mixed gas to be measured. The compensation formula is: C 第二待测混合气体 =C 第二待测混合气体的原始浓度 +K T ×(T 第二测量温度 -T 基准温度 )+K H ×(H 第二测量湿度 -H 基准湿度 ), where K T is the temperature compensation value, K H is the humidity compensation value; The compensated gas concentration is obtained by using the compensation formula and recorded as the compensated concentration of the second gas to be measured; The average value of the first gas compensation concentration and the second gas compensation concentration is calculated and recorded as the target gas concentration in the measured space.

Images