Gas detection method and device based on multi-sensor combination

Abstract

The invention relates to the field of gas detection, and discloses a gas detection method and device based on a multi-sensor combination, and the method comprises the steps: constructing the multi-sensor combination, and obtaining the output value of the multi-sensor combination; the multi-sensor combination comprises a first sensor and a second sensor; wherein the output values of the first sensor and the second sensor comprise a first gas value and / or a second gas value; the first sensor and the second sensor are both configured to be in linear response to any one of a first gas and a second gas; the first sensor and the second sensor are configured to be sensors with different detection principles; calculating the concentration value of the first gas and / or the second gas based on the output value of the first sensor and the output value of the second sensor; the problem that in the prior art, when the first gas is detected, due to the influence of the second gas, the output result of the sensor is not accurate is solved.

Description

Technical Field

[0001] The present invention relates to the field of gas detection, and in particular to a gas detection method and device based on a multi-sensor combination. Background Art

[0002] Gas detection has a wide range of applications, including industrial production, environmental protection, medical diagnosis, etc. In industrial production, gas detection is used to monitor the emission of harmful gases to ensure the safety of the working environment; in environmental protection, it is used to detect pollutants in the atmosphere; in medical diagnosis, it is used to detect the composition of respiratory gases to assist in disease diagnosis.

[0003] Existing sensors for gas detection often only measure the refrigerant gas to be tested; taking sensors for refrigerant gas detection as an example, patent applications such as DE202023103907U1 for refrigerant gas leak detection sensor, CN116930270A gas detection probe, CN118392948A gas sensor, etc., all detect a single refrigerant gas to be tested, and the above measurements ignore the impact of certain specific interfering gases on the gas detection sensor. When certain specific interfering gases are present, the gas detection sensor will respond to the interfering gas, and the measured value output by it may be biased. Summary of the invention

[0004] The purpose of the present invention is to propose a gas detection method and device based on a multi-sensor combination to solve the above technical problems.

[0005] Specifically, the present invention provides a gas detection method based on a multi-sensor combination, comprising the following steps: S1: constructing a multi-sensor combination and obtaining its output value; the multi-sensor combination comprises: a first sensor and a second sensor; wherein the output values ​​of the first sensor and the second sensor both comprise a first gas value and a second gas value; the first sensor and the second sensor are both configured to respond linearly to either the first gas or the second gas; the first sensor and the second sensor are configured as sensors with different detection principles; S2: calculating the concentration value of the first gas and / or the second gas based on the output value of the first sensor and the output value of the second sensor.

[0006] The present invention also provides a gas detection device based on a multi-sensor combination, comprising: a first sensor, a second sensor and a controller; the first sensor and the second sensor are configured to output values, and each output value includes a first gas value and / or a second gas value; the first sensor and the second sensor are both configured to respond linearly to any one of the first gas and the second gas; the first sensor and the second sensor are configured as sensors with different detection principles; the controller executes the steps of the above-mentioned gas detection method based on a multi-sensor combination.

[0007] The beneficial effect provided by the present invention is that at least the output of the concentration of the first gas and / or the second gas can be realized. Therefore, when the target gas to be detected by the sensor is affected by a certain interfering gas, the target gas and the interfering gas can be used as the first gas and the second gas respectively through the present invention, and then the output value of the target gas will not produce errors due to the presence of the interfering gas; in addition, when two gases need to be detected, the scheme of the present invention can also be used to directly output the concentration values ​​of the two gases. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a schematic flow chart of the method of the present invention; Figure 2 is a schematic flow chart of step S2 in the first case of the present invention; Figure 3 is a schematic flow chart of step S2 in the second situation of the present invention; Figure 4 is a schematic flow chart of step S2 in the third situation of the present invention; Figure 5 is a schematic flow chart of step S2 in the fourth situation of the present invention; Figure 6 This is a schematic diagram of the detection process of the first case after adding the humidity sensor; Figure 7 This is a schematic diagram of the detection process of the second case after adding the humidity sensor; Figure 8 A coordinate diagram showing how the first gas value of each of the first sensor and the second sensor changes with the first gas concentration; Fig. 9 It is a schematic diagram of the device of the present invention. DETAILED DESCRIPTION

[0009] To make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0010] Before formally describing the present invention, the scheme of the present invention is first generally described for easy understanding.

[0011] Please refer to Figure 1 , Figure 1 It is a schematic flow chart of the method of the present invention.

[0012] The present invention provides a gas detection method based on a multi-sensor combination, comprising the following steps: S1: construct a multi-sensor combination and obtain its output value; the multi-sensor combination includes: a first sensor and a second sensor; wherein the output values ​​of the first sensor and the second sensor both include a first gas value and a second gas value; It should be noted that the first or second sensor actually outputs only one value, but the output value may include the first gas value and / or the second gas value, which does not mean that the sensor output value includes two values. More specifically, it is the variable generated by the first or second sensor under the influence of the first gas and / or the variable generated by the influence of the second gas. For the convenience of explanation, these two variables are respectively referred to as the first gas value and the second gas value in the present invention.

[0013] It should be particularly noted that, in the embodiment of the present invention, the first gas refers to the gas to be measured, and the second gas refers to the interfering gas. Of course, in some other embodiments, the order of reference may also be replaced.

[0014] Based on the above concept, if there is only the gas to be measured in the gas chamber, the first and second sensors output only the value of the gas to be measured; if there is only the interfering gas in the gas chamber, the first and second sensors output only the value of the interfering gas; if there is both the gas to be measured and the interfering gas in the gas chamber, the value output by the first and second sensors is a combination of the values ​​of the interfering gas and the gas to be measured.

[0015] It should be supplemented that, in some other embodiments, the first gas and the second gas may both be target gases to be measured.

[0016] The first sensor and the second sensor are both configured to respond linearly to any one of the first gas and the second gas; it should be noted that the linear response specifically means that when the gas concentration changes, the corresponding response of the sensor also changes linearly and proportionally.

[0017] The first sensor and the second sensor are configured as sensors with different detection principles; The detection principle of the sensor refers to the ability of the sensor to sense the measured information and convert it into electrical signals or other required forms of information output according to certain rules to meet the requirements of information transmission, processing, and control.

[0018] It should be noted that, in this embodiment, the first sensor is an ultrasonic sensor and the second sensor is a thermal conductivity sensor. In other embodiments, as long as the above-mentioned limitations on the first sensor and the second sensor are met, the present application does not limit the actual detection principle of the sensor.

[0019] Ultrasonic sensor: Ultrasonic gas sensing technology uses the principle of measuring the speed of sound propagation of ultrasonic waves, then measures the average molecular weight of the gas, and then calculates the concentration of the gas to be measured. It has the advantages of small size, low power consumption, fast response time and long life.

[0020] Thermal conductivity sensor: The gas concentration is measured based on the difference in thermal conductivity of different gases at a certain temperature. The application of thermal conductivity gas sensors in the field of refrigerant leak detection has the characteristics of small size, high reliability and fast response time.

[0021] S2: Calculate the concentration value of the first gas and / or the second gas based on the output value of the first sensor and the output value of the second sensor.

[0022] It can be understood that in the actual process, the influence of the first gas and the second gas on the first sensor and the second sensor can be obtained, and the concentrations of the first gas and the second gas can be taken as unknown quantities. Then, equations are listed through the output values ​​of the first sensor and the second sensor, and the concentration values ​​of the first gas and / or the second gas can be calculated by solving the equations.

[0023] Preferably, the first sensor and the second sensor are calibrated before actual measurement, specifically: when the concentration of the first gas changes by a certain value, the first gas value generated by the first sensor based only on the change in the concentration of the first gas and the first gas value generated by the second sensor based only on the change in the concentration of the first gas are the same; by Figure 8 For example, the influence of the first gas on the first sensor is shown in line 1: Y1=K1X; the influence of the first gas on the second sensor is shown in line 2: Y2=K2X; where X is the actual concentration of the first gas, and Y1 and Y2 are the change values ​​of the first sensor and the second sensor affected by the first gas. When it is necessary to achieve that when the concentration of the first gas changes, the first gas value generated by the first sensor based only on the change of the first gas concentration is the same as the first gas value generated by the second sensor based only on the change of the first gas concentration, there are three ways to achieve this.

[0024] 1. The coefficient of the first sensor can be adjusted, such as by using K1×K3=K2, the influence of the first gas on the first sensor is changed to: Y1=K1×K3X, at this time, the function line coincides with the above line 2; 2. The coefficient of the second sensor can be adjusted, such as by using K2×K4=K1, the influence of the first gas on the second sensor is changed to: Y2=K2×K4X, at this time, the function line coincides with the above line 1; 3. The coefficients of the first sensor and the second sensor are adjusted, so that the two adjusted function lines become Y=K5X.

[0025] At this time, when the second gas concentration changes, the second gas value generated by the first sensor based only on the change in the second gas concentration is X times the second gas value generated by the second sensor based only on the change in the second gas concentration.

[0026] It should be noted that the X times can be determined based on the response coefficients of the first sensor and the second sensor based on the second gas and the values ​​corrected for the first sensor and / or the second sensor in the above steps.

[0027] The above process is essentially the calibration process of the first sensor and the second sensor before measurement. After calibration, the following conclusions can be obtained: the response values ​​of the first sensor and the second sensor to the first gas are the same, and the responses of the first sensor and the second sensor to the second gas or the interfering gas are in an X-fold relationship.

[0028] In this way, combined with steps S1 and S2, we can get C1=C+C2; C3=C+C4; C2=X×C4; where C1 is the output value of the first sensor, C is the first gas value of the first sensor and also the first gas value of the second sensor, C2 is the second gas value of the first sensor, C3 is the output value of the second sensor, and C4 is the second gas value of the second sensor. At this time, the unknown quantities are C, C2, and C4, which can be solved by the simultaneous equations.

[0029] Please refer to Figure 2 , Figure 2 is a schematic flow chart of step S2 in the first case of the present invention; Step S2 includes the following: S21, determining whether the output value of the first sensor is the same as the output value of the second sensor, if so, taking the measurement value of the sensor with higher measurement accuracy of the first sensor or the second sensor as the concentration value of the first gas; otherwise, proceeding to step S22; Of course, if only the concentration value of the first gas needs to be output here, it can be output directly; If the concentration of the second gas is required, no result may be output at this time, or the output second gas concentration value may be 0; If the concentration of the first gas and the concentration of the second gas need to be output simultaneously, the concentration of the first gas is directly outputted, and for the second gas, the second gas concentration value may be outputted as 0, or no result may be displayed.

[0030] S22, calculating the concentration value of the first gas and / or the second gas according to the output value of the first sensor and the output value of the second sensor; Or, please refer to Figure 3 , Figure 3 is a schematic flow chart of step S2 in the second situation of the present invention; S21, determining whether the output value of the first sensor is the same as the output value of the second sensor, if so, taking the measured value of one of the sensors as the concentration value of the first gas; otherwise, proceeding to step S22; S22, determining whether the output value of the first sensor is X times the output value of the second sensor, if so, taking the measurement value of the sensor with higher measurement accuracy between the first sensor and the second sensor or the measurement value of one of the sensors as the second gas concentration value; otherwise, proceeding to step S23; It should be noted that if only the concentration value of the second gas needs to be output here, it can be output directly; If the concentration of the first gas is required, no result may be output at this time, or the output first gas concentration value may be 0; If the concentration of the first gas and the concentration of the second gas need to be output simultaneously, the concentration of the second gas is directly outputted at this time, and for the first gas, the first gas concentration value may be outputted as 0, or no result may be displayed.

[0031] S23, calculating the concentration value of the first gas and / or the second gas according to the output value of the first sensor and the output value of the second sensor; Or, please refer to Figure 4 , Figure 4 is a schematic flow chart of step S2 in the third situation of the present invention; S21, determining whether the output value of the first sensor is X times the output value of the second sensor, if so, taking the measurement value of the sensor with higher measurement accuracy between the first sensor and the second sensor or the measurement value of one of the sensors as the second gas concentration value; otherwise, proceeding to step S22; It should be noted that if only the concentration value of the second gas needs to be output here, it can be output directly; If the concentration of the first gas is required, no result may be output at this time, or the output first gas concentration value may be 0; If the concentration of the first gas and the concentration of the second gas need to be output simultaneously, the concentration of the second gas is directly outputted at this time, and for the first gas, the first gas concentration value may be outputted as 0, or no result may be displayed.

[0032] S22, calculating the concentration value of the first gas and / or the second gas according to the output value of the first sensor and the output value of the second sensor; Or, please refer to Figure 5 , Figure 5 is a schematic flow chart of step S2 in the fourth situation of the present invention; S21, determining whether the output value of the first sensor is X times the output value of the second sensor, if so, taking the measurement value of the sensor with higher measurement accuracy between the first sensor and the second sensor or the measurement value of one of the sensors as the second gas concentration value; otherwise, proceeding to step S22; It should be noted that if only the concentration value of the second gas needs to be output here, it can be output directly; If the concentration of the first gas is required, no result may be output at this time, or the output first gas concentration value may be 0; If the concentration of the first gas and the concentration of the second gas need to be output simultaneously, the concentration of the second gas is directly output at this time. For the first gas, the first gas concentration value can be output as 0, or no result is displayed; S22, determining whether the output value of the first sensor is the same as the output value of the second sensor, if so, taking the measured value of one of the sensors as the concentration value of the first gas; otherwise, proceeding to step S23; Of course, if only the concentration value of the first gas needs to be output here, it can be output directly; If the concentration of the second gas is required, no result may be output at this time, or the output second gas concentration value may be 0; If the concentration of the first gas and the concentration of the second gas need to be output simultaneously, the concentration of the first gas is directly output, and for the second gas, the second gas concentration value can be output as 0, or no result is displayed; S23. Calculate the concentration value of the first gas and / or the second gas according to the output value of the first sensor and the output value of the second sensor.

[0033] The present invention further improves the sensitivity of the sensor. For the convenience of description, it is assumed that the first gas is the target gas (also referred to as the aforementioned gas to be measured) and the second gas is the interference gas; specifically: The first sensor is configured such that the effect of the first gas to be detected on the sensor signal value is positive or negative as is the effect of the second gas to be detected on the sensor signal value; The second sensor is configured such that one of the influence of the first gas to be detected on the sensor signal value and the influence of the second gas to be detected on the sensor signal value is positive and the other is negative; At this time, in step S2, the target gas value is calculated based on the output value of the first sensor and the output value of the second sensor, or the target gas value and the interfering gas value are calculated.

[0034] It should be noted that the positive or negative impact of the aforementioned detected gas on the sensor signal value is understood as follows: As mentioned above, different sensor types have different responses to different gases. Here are the details: According to the measurement principle of ultrasonic sensors, the greater the difference between the molecular mass of the test mixed gas and the molecular mass of the background gas, the greater the sensor response. For example, the higher the concentration of the test gas, the higher the molecular mass after mixing with air than the molecular mass of air, and the higher the sensor response. According to the measurement principle of thermal conductivity sensor, the greater the difference between the thermal conductivity of the test mixed gas and the thermal conductivity of the background gas air, the greater the sensor response. For example, the higher the concentration of the test gas, the greater the difference between the thermal conductivity of the mixed gas and the pure air, and the higher the sensor response. For example, when the gas is only air, the gas molecular mass measured by the ultrasonic sensor is 28.8g / mol, and when the gas to be measured is only ethanol, the gas molecular mass measured by the ultrasonic sensor is: 46g / mol; this shows that when the concentration of ethanol in the mixed gas of air and ethanol is higher, the value measured by the ultrasonic sensor is closer to 46g / mol, which is greater than 28.8g / mol of pure air. In other words, it reflects that the higher the concentration of ethanol, the greater the value measured by the ultrasonic sensor.

[0035] When the gas is only air, the thermal conductivity coefficient tested by the thermal conductivity sensor is 25.9mW / (m·K). When the gas to be tested is only ethanol, the gas molecular mass tested by the thermal conductivity sensor is: 15.2mW / (m·K). This shows that when the concentration of ethanol in the mixed gas of air and ethanol is higher, the value measured by the thermal conductivity sensor is closer to 15.2mW / (m·K), which is smaller than the 25.9mW / (m·K) of pure air. In other words, it is reflected that the higher the concentration of ethanol, the smaller the value measured by the thermal conductivity sensor.

[0036] That is, taking the same gas to be measured, ethanol, as an example, the ultrasonic sensor responds positively to its changes, while the thermal conductivity sensor responds negatively to its changes.

[0037] For example, when the gas is only air, the gas molecular mass measured by the ultrasonic sensor is 28.8g / mol, and when the gas to be measured is only water vapor, the gas molecular mass measured by the ultrasonic sensor is: 18g / mol; this shows that when the water vapor concentration in the mixed gas of air and water vapor is higher, the value measured by the ultrasonic sensor is closer to 18.4g / mol, which is less than 28.8g / mol of pure air. In other words, it reflects that the higher the water vapor concentration, the smaller the value measured by the ultrasonic sensor.

[0038] When the gas is only air, the thermal conductivity coefficient tested by the thermal conductivity sensor is 25.9mW / (m·K). When the gas to be tested is only water vapor, the gas molecular mass tested by the thermal conductivity sensor is: 18.4mW / (m·K). This shows that when the water vapor concentration in the mixed gas of air and water vapor is higher, the value measured by the thermal conductivity sensor is closer to 18.4mW / (m·K), which is less than the 25.9mW / (m·K) of pure air. In other words, it reflects that the higher the water vapor concentration, the smaller the value measured by the thermal conductivity sensor.

[0039] That is, taking the same gas to be measured, water vapor, and the background gas being air as an example, the ultrasonic sensor responds to its changes in the opposite direction, and the thermal conductivity sensor responds to its changes in the negative direction. This is the concept of positive and negative directions mentioned in the present invention.

[0040] Based on the above concept, the aforementioned “the first sensor is configured such that the effect of the first gas to be detected on the sensor signal value and the effect of the second gas to be detected on the sensor signal value are both positive or negative” can be understood as: The ultrasonic sensor responds to changes in the first gas to be measured and the second gas to be measured in a positive direction, or the ultrasonic sensor responds to changes in the first gas to be measured and the second gas to be measured in a negative direction.

[0041] For example, if the first gas to be measured in the above-mentioned test is water vapor, and the ultrasonic sensor responds negatively to its change, then the ultrasonic sensor's response to the change of the second gas to be measured should also be negative, such as if the second gas to be measured is methane; for example, if the first gas to be measured in the above-mentioned test is ethanol, and the ultrasonic sensor responds positively to its change, then the ultrasonic sensor's response to the change of the second gas should also be positive, such as if the second gas to be measured is CO2.

[0042] Of course, in the above description process, the ultrasonic sensor is assumed to be the first sensor and the thermal conductivity sensor is assumed to be the second sensor. It should be noted that in some other embodiments, the types of the first sensor and the second sensor can also be interchanged. This is only used for explanation and not for limitation.

[0043] Based on the above concept, the aforementioned “the second sensor is configured such that one of the influence of the first gas to be detected on the sensor signal value and the influence of the second gas to be detected on the sensor signal value is positive and the other is negative;” can be understood as, If the thermal conductivity sensor responds positively to changes in the first gas to be measured, the thermal conductivity sensor responds negatively to changes in the second gas to be measured; or, if the thermal conductivity sensor responds negatively to changes in the first gas to be measured, the thermal conductivity sensor responds positively to changes in the second gas to be measured.

[0044] For example, if the first gas to be measured is water vapor and the thermal conductivity sensor responds negatively to its change, then the thermal conductivity sensor should respond positively to the change of the second gas to be measured, for example, the second gas to be measured is methane; for example, if the first gas to be measured is methane and the thermal conductivity sensor responds positively to its change, then the thermal conductivity sensor should respond negatively to the change of the second gas to be measured, for example, the second gas to be measured is water vapor.

[0045] Taking the calculation of the first gas value as an example, as mentioned above: C1=C+C2; C3=C+C4; C2=X×C4; Among them, C1 is the output value of the first sensor, C is the first gas value of the first sensor and also the first gas value of the second sensor, C2 is the second gas value of the first sensor, C3 is the output value of the second sensor, and C4 is the second gas value of the second sensor. At this time, the unknown quantities are C, C2, and C4, which can be solved by the simultaneous equations, and C=(C1-C3×X) / (1-X); As an embodiment, the first gas is methane and the second gas is water vapor. The first gas is the target gas and the second gas is the interference gas. At this time, the ultrasonic sensor (first sensor) responds negatively to changes in water vapor and methane, that is, the interference gas has the same effect on the ultrasonic sensor as the gas to be measured; the thermal conductivity sensor (second sensor) responds negatively to changes in water vapor and positively to changes in methane, that is, the interference gas has an opposite effect on thermal conductivity compared to the gas to be measured. At this time, the aforementioned K1 is a negative value, and K2 is a positive value. To adjust the coefficient of the second sensor, K4=K1 / K2, K4 is a negative value, and X is related to K4 and the slope of the line of the first sensor and the second sensor that changes with the second gas. Because K4 is a negative value, and the slopes of the lines of the first sensor and the second sensor that change with the second gas are both negative values, X is a negative value. When X is a negative value, in the above formula C=(C1-C3×X) / (1-X), due to the influence of C3, the increase in the numerator is actually smaller than the denominator, so the final C is larger than when X is a positive value, which is reflected in the increase in the response sensitivity of the combined sensor.

[0046] It should be noted that, before step S1, or in step S1, a humidity measurement value is also obtained by a humidity sensor. On this basis, please refer to Figure 6 , Figure 6 This is a schematic diagram of the detection process of the first case after adding the humidity sensor; The output value of the first sensor and the output value of the second sensor are combined with the humidity measurement value to remove the humidity influence, and then the concentration value of the first gas and / or the second gas is calculated; Or, please refer to Figure 7 , Figure 7 This is a schematic diagram of the detection process of the second case after adding the humidity sensor; When calculating the concentration value of the first gas and / or the second gas based on the output value of the first sensor and the output value of the second sensor, the humidity measurement value is substituted into the calculation as a known constant to remove the influence of humidity.

[0047] In the present invention, a humidity sensor is added to detect humidity, thereby eliminating the influence of humidity on the detection result during the detection process, and further improving the detection accuracy.

[0048] It should be noted that Figure 6 In the example shown, the step of obtaining the humidity value by using the humidity sensor is placed before step S1 . However, in this example, the step of obtaining the humidity value by using the humidity sensor may also be placed in step S1 . Figure 7 In the example shown, the step of obtaining the humidity value by using the humidity sensor is in step S1 . However, in this example, the step of obtaining the humidity value by using the humidity sensor may be before step S1 .

[0049] It should be noted that, when there are third to Nth gases that need to be measured, the multi-sensor combination further includes the third to Nth sensors, or the first sensor is a thermal conductivity or MOX sensor; When the multi-sensor combination further includes a third sensor to an Nth sensor, each sensor has a different measurement principle, an output value of each sensor includes some of the first gas value to the Nth gas value, and each sensor is configured to respond linearly to any one of the first gas to the Nth gas; At this time, the step S2 includes calculating the concentration of some of the first gas value to the Nth gas value based on the output values ​​of the first sensor to the Nth sensor; It should be noted that, here the first gas is taken as the target gas, and the second to Nth gases are all interference gases for illustration. Of course, in the actual process, the first to Nth gases can all be target gases, or can all be interference gases, or some of them can be target gases and some can be interference gases. This does not affect the specific calculation process.

[0050] According to the calculation method similar to the above, the solution process should be: C1=C0+Y 11 +Y 12 +…+Y 1（N-1） ; C2=C0+Y 21 +Y 22 +…+Y 2（N-1） ; C3=C0+Y 31 +Y 32 +…+Y 3（N-1） ; … C N =C0+Y N1 +Y N2 +…+Y N（N-1） ; Among them, C1-C N is the display value of the first to Nth sensors; C0 is the value of the target gas, Y 11 is the response value of the first sensor to the second gas. Similarly, Y 1（N-1） is the response value of the first sensor to the Nth gas; Y 21 is the response value of the second sensor to the second gas. Similarly, Y 2（N-1） is the response value of the second sensor to the Nth gas; Y 31 is the response value of the third sensor to the second gas. Similarly, Y 3（N-1） Y is the response value of the third sensor to the Nth gas; N1 is the response value of the Nth sensor to the second gas. Similarly, Y N（N-1） is the response value of the Nth sensor to the Nth gas; It should be noted that, using the above calibration, Y 21 To Y N1 You can use Y 11 Multiply by a certain coefficient to express, similarly, Y 22 To Y N2 You can use Y 12 Multiply by a certain coefficient to express, ..., Y 2(N-1) To Y N（N-1） You can use Y 1(N-1) It is expressed by multiplying by a certain coefficient; There are a total of N equations above. Solve the equations from C0, Y 11 , Y 12 …Y 1（N-1） There are N unknowns in total.

[0051] When the first sensor is a thermal conductivity or MOX sensor, the first sensor outputs N-1 output values ​​at at least N-1 temperatures; At this time, the step S2 includes calculating the concentration of some of the first gas value to the Nth gas value based on the N-1 output values ​​of the first sensor and the output value of the second sensor.

[0052] Specifically, the mixed gas is composed of the first gas to the Nth gas. At this time, the first sensor outputs different values ​​at different set temperatures. For example, at the first set temperature t 1, the output value of the first sensor is C 1. refers to C 1 includes all or some of the first gas to the Nth gas, which can be expressed as: C1=C0+Y 11 +Y 12 +…+Y 1（N-1） ; Where C0 is the response value of the first sensor to the first gas; Y 11 is the response value of the first sensor to the second gas at the first set temperature t1; 1（N-1） is the response value of the first sensor to the Nth gas; correspondingly, at different set temperatures N-1, there are: C N-1 =C0+Y (N-1)1 +Y (N-1)2 +…+Y (N-1)（N-1） Add the output value C of the second sensor N =C0+Y N1 +Y N2 +…+Y N（N-1） , a total of N equations, and Y 21 To Y N1 You can use Y 11 Multiply by a certain coefficient to express, similarly, Y 22 To Y N2 You can use Y 12 Multiply by a certain coefficient to express, ..., Y 2(N-1) To Y N（N-1） You can use Y 1(N-1) By multiplying by a certain coefficient, the concentrations of the first gas to the Nth gas or some of their concentrations can be obtained by solving them simultaneously.

[0053] It should be noted that the first gas is a target gas, and at least two of the second to Nth gases are interference gases; When the multi-sensor combination further includes the third sensor to the Nth sensor, the first sensor is configured such that the effect of the target gas on the sensor signal value and the effect of the interference on the sensor signal value are both positive or negative, and at least two of the second to the Nth sensors are configured such that one of the effect of the target gas on the sensor signal value and the effect of the interference gas on the sensor signal value is positive and the other is negative; It should be noted that the process of improving the sensitivity is substantially the same as the above corresponding situation, the only difference being that there are one or more gases to be measured or interfering gases.

[0054] Or, when the multi-sensor combination further includes the third to Nth sensors, the first sensor is configured such that one of the effect of the target gas on the sensor signal value and the effect of the interference on the sensor signal value is positive and the other is negative, and at least two of the second to Nth sensors are configured such that the effect of the target gas on the sensor signal value and the effect of the interference gas on the sensor signal value are both positive or negative; or, when the first sensor is a thermal conductivity or MOX sensor, the first sensor is configured such that the effect of the target gas on the sensor signal value and the effect of the interference gas on the sensor signal value are both positive or negative at at least two temperatures; the second sensor is configured such that the effect of the target gas on the sensor signal value and the effect of the interference gas on the sensor signal value are both positive or negative; The first sensor is configured such that the effect of the target gas on the sensor signal value and the effect of the interfering gas on the sensor signal value are both positive and negative; or, when the first sensor is a thermal conductivity or MOX sensor, the first sensor is configured such that the effect of the target gas on the sensor signal value and the effect of the interfering gas on the sensor signal value are both positive and negative at at least two temperatures; the second sensor is configured such that the effect of the target gas on the sensor signal value and the effect of the interfering gas on the sensor signal value are both positive or negative; at this time, the target gas value is calculated based on the output value of the first sensor and the output value of the second sensor, or the target gas value and some of the interfering gas are calculated. In this way, the sensitivity when measuring the target gas can also be improved.

[0055] The device of the present invention includes: a first sensor, a second sensor and a controller; the first sensor and the second sensor are configured to output values, and each output value includes a first gas value and / or a second gas value; the first sensor and the second sensor are both configured to respond linearly to any one of the first gas and the second gas; the first sensor and the second sensor are configured as sensors with different detection principles; the controller executes the steps of the above-mentioned gas detection method based on a multi-sensor combination.

[0056] As another example, please refer to Fig. 9 , Fig. 9 It is a schematic diagram of the device of the present invention.

[0057] A gas detection device based on a multi-sensor combination includes: an upper cover 2-1 with an air intake grille, a lower cover 2-10, a buckle design is adopted between the upper cover 2-1 and the lower cover 2-10, and a multi-sensor combination and a humidity sensor ( Fig. 9 Not shown), PCB board 2-8, where the multi-sensor combination and humidity sensor are soldered on PCB board 2-8 and connected to the controller on PCB board 2-8 ( Fig. 9 The PCB board is also provided with a first shielding cover 2-3 and a waterproof breathable membrane 2-2 from bottom to top; a second shielding cover 2-9 is also provided between the PCB board 2-8 and the lower cover 2-10; The controller includes a processor and a storage medium; the processor loads and executes instructions and data in the storage medium to implement the gas detection method based on a multi-sensor combination.

[0058] It should be noted that the multi-sensor combination is: a group of ultrasonic detectors 2-4 and a thermal conductivity sensor chip 2-7; two groups of ultrasonic detector air chambers are also arranged next to the ultrasonic detector 2-4, namely the first ultrasonic sensor air chamber 2-5 and the second ultrasonic sensor air chamber 2-6.

[0059] The operating principle of the device is as follows: The test gas passes through the upper cover 2-1 and the waterproof breathable membrane 2-2 into the integrated sensor chamber. The chamber contains a second ultrasonic sensor chamber 2-6 and a thermal conductivity sensor chip 2-7. The ultrasonic and thermal conductivity sensors measure the concentration of the gas entering. The controller compares the measurement signals of the ultrasonic and thermal conductivity sensors to determine the influence of the environmental interference gas, thereby improving the reliability of the measurement results. At the same time, the temperature and humidity chip in the integrated sensor chamber measures the ambient temperature and humidity. The temperature and humidity measurement results will correct the ultrasonic and thermal conductivity measurement results, thereby improving the accuracy of the sensor output results. When the test gas concentration exceeds the alarm value, an alarm signal is output. In addition, the first shielding cover 2-3 and the second shielding cover 2-9 can effectively shield external electromagnetic interference and improve the sensor's anti-interference performance.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A gas detection method based on multi-sensor combination, characterized in that: The method comprises the following steps: S1: Build a multi-sensor combination and obtain its output value; The multi-sensor combination includes: a first sensor and a second sensor; The output values ​​of the first sensor and the second sensor both include a first gas value and a second gas value; the first sensor and the second sensor are both configured to respond linearly to either the first gas or the second gas; the first sensor and the second sensor are configured to be sensors with different detection principles; S2: Calculating the concentration value of the first gas and / or the second gas based on the output value of the first sensor and the output value of the second sensor; Specifically, the influence of the first gas and the second gas on the first sensor and the second sensor is obtained, and the concentrations of the first gas and the second gas are taken as unknown quantities. Then, equations are listed based on the output values ​​of the first sensor and the second sensor, and the concentration values ​​of the first gas and / or the second gas are calculated by solving the equations.

2. A gas detection method based on multi-sensor combination as claimed in claim 1, characterized in that: The first sensor and the second sensor are calibrated before actual measurement, specifically: when the concentration of the first gas changes by a certain value, the first gas value generated by the first sensor based only on the change in the concentration of the first gas is the same as the first gas value generated by the second sensor based only on the change in the concentration of the first gas; At this time, when the second gas concentration changes by a certain value, the second gas value generated by the first sensor based only on the change in the second gas concentration is X times the first gas value generated by the second sensor based only on the change in the first gas concentration.

3. A gas detection method based on multi-sensor combination as claimed in claim 2, characterized in that: Step S2 includes the following: S21, determining whether the output value of the first sensor is the same as the output value of the second sensor, if so, taking the measurement value of the sensor with higher measurement accuracy of the first sensor or the second sensor as the concentration value of the first gas; otherwise, proceeding to step S22; S22, calculating the concentration value of the first gas and / or the second gas according to the output value of the first sensor and the output value of the second sensor; or, S21, determining whether the output value of the first sensor is the same as the output value of the second sensor, if so, taking the measured value of one of the sensors as the concentration value of the first gas; otherwise, proceeding to step S22; S22, determining whether the output value of the first sensor is X times the output value of the second sensor, and if so, taking the measurement value of the sensor with higher measurement accuracy between the first sensor and the second sensor or the measurement value of one of the sensors as the second gas concentration value; Otherwise, proceed to step S23; S23, calculating the concentration value of the first gas and / or the second gas according to the output value of the first sensor and the output value of the second sensor; or, S21, determining whether the output value of the first sensor is B times the output value of the second sensor, if so, taking the measurement value of the sensor with higher measurement accuracy between the first sensor and the second sensor or the measurement value of one of the sensors as the second gas concentration value; otherwise, proceeding to step S22; S22, calculating the concentration value of the first gas and / or the second gas according to the output value of the first sensor and the output value of the second sensor; or, S21, determining whether the output value of the first sensor is X times the output value of the second sensor, if so, taking the measurement value of the sensor with higher measurement accuracy between the first sensor and the second sensor or the measurement value of one of the sensors as the second gas concentration value; otherwise, proceeding to step S22; S22, determining whether the output value of the first sensor is the same as the output value of the second sensor, if so, taking the measured value of one of the sensors as the concentration value of the first gas; otherwise, proceeding to step S23; S23. Calculate the concentration value of the first gas and / or the second gas according to the output value of the first sensor and the output value of the second sensor.

4. A gas detection method based on multi-sensor combination as claimed in claim 1 or 2, characterized in that: The first gas is the target gas, and the second gas is the interference gas; The first sensor is configured such that the effect of the first gas to be detected on the sensor signal value is positive or negative as is the effect of the second gas to be detected on the sensor signal value; The second sensor is configured such that one of the influence of the first gas to be detected on the sensor signal value and the influence of the second gas to be detected on the sensor signal value is positive and the other is negative; At this time, in step S2, the target gas value is calculated based on the output value of the first sensor and the output value of the second sensor, or the target gas value and the interfering gas value are calculated.

5. The gas detection method based on multi-sensor combination as claimed in claim 1, characterized in that: Before step S1 , or in step S1 , a humidity measurement value is also obtained by a humidity sensor.

6. A gas detection method based on multi-sensor combination as claimed in claim 5, characterized in that: Step S2 specifically includes: The output value of the first sensor and the output value of the second sensor are combined with the humidity measurement value to remove the influence of humidity, and then the concentration value of the first gas and / or the second gas is calculated; or, when the concentration value of the first gas and / or the second gas is calculated based on the output value of the first sensor and the output value of the second sensor, the humidity measurement value is substituted into the calculation as a known constant to remove the influence of humidity.

7. A gas detection method based on multi-sensor combination as claimed in claim 1, characterized in that: When there are third to Nth gases that need to be measured, the multi-sensor combination further includes the third to Nth sensors, or the first sensor is a thermal conductivity or MOX sensor; When the multi-sensor combination further includes a third sensor to an Nth sensor, each sensor has a different measurement principle, an output value of each sensor includes some of the first gas value to the Nth gas value, and each sensor is configured to respond linearly to any one of the first gas to the Nth gas; At this time, the step S2 includes calculating the concentration of some of the first gas value to the Nth gas value based on the output values ​​of the first sensor to the Nth sensor; When the first sensor is a thermal conductivity or MOX sensor, the first sensor outputs N-1 output values ​​at at least N-1 temperatures; At this time, the step S2 includes calculating the concentration of some of the first gas value to the Nth gas value based on the N-1 output values ​​of the first sensor and the output value of the second sensor.

8. A gas detection method based on multi-sensor combination as claimed in claim 7, characterized in that: The first gas is a target gas, and at least two of the second to Nth gases are interference gases; When the multi-sensor combination further includes the third sensor to the Nth sensor, the first sensor is configured such that the effect of the target gas on the sensor signal value and the effect of the interference on the sensor signal value are both positive or negative, and at least two of the second to the Nth sensors are configured such that one of the effect of the target gas on the sensor signal value and the effect of the interference gas on the sensor signal value is positive and the other is negative; Or, when the multi-sensor combination further includes the third sensor to the Nth sensor, the first sensor is configured such that one of the effect of the target gas on the sensor signal value and the effect of the interference on the sensor signal value is positive and the other is negative, and at least two of the second to the Nth sensors are configured such that the effect of the target gas on the sensor signal value and the effect of the interference gas on the sensor signal value are both positive or negative; Or, when the first sensor is a thermal conductivity or MOX sensor, the first sensor is set at at least two temperatures so that the effect of the target gas on the sensor signal value and the effect of the interference gas on the sensor signal value are both positive or negative; the second sensor is set so that one of the effect of the target gas on the sensor signal value and the effect of the interference gas on the sensor signal value is positive and the other is negative; Or, when the first sensor is a thermal conductivity or MOX sensor, the first sensor is set at at least two temperatures so that the effect of the target gas on the sensor signal value and the effect of the interference gas on the sensor signal value are both positive and negative; the second sensor is set so that the effect of the target gas on the sensor signal value and the effect of the interference gas on the sensor signal value are both positive or negative; At this time, the target gas value is calculated based on the output value of the first sensor and the output value of the second sensor, or the target gas value and the interference gas value are calculated.

9. A gas detection method based on multi-sensor combination as claimed in claim 1, characterized in that: The first sensor is a thermal conductivity sensor, and the second sensor is an ultrasonic sensor.

10. A gas detection device based on a multi-sensor combination, characterized in that: include: A first sensor, a second sensor and a controller; the first sensor and the second sensor are configured to output values, and each output value includes a first gas value and / or a second gas value; the first sensor and the second sensor are configured to respond linearly to either the first gas or the second gas; the first sensor and the second sensor are configured as sensors with different detection principles; the controller executes the steps of the gas detection method based on a multi-sensor combination as described in any one of claims 1 to 9.

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