Sensitivity evaluation method and evaluation device for infrared gas cloud imaging device

Abstract

The invention relates to a sensitivity evaluation method and evaluation device for an infrared gas cloud imaging device, and belongs to the field of gas detection. The evaluation method comprises the following steps: under a certain temperature condition, to-be-detected gases with the same type and different concentration gradients sequentially pass through gas constraint tubes with preset lengths according to a concentration sequence from small to large; the gas cloud spectrum camera sequentially captures spectrum images of to-be-detected gas with different concentration gradients in the gas constraint pipe and judges whether leakage exists or not according to the spectrum images; and if leakage exists, determining the sensitivity of the infrared gas cloud imaging device according to the corresponding concentration of the to-be-detected gas during leakage. The sensitivity of the infrared gas cloud imaging device can be determined according to the concentration of the corresponding to-be-detected gas during leakage, and the method is simple to operate and easy to implement.

Description

Technical Field

[0001] The invention relates to a sensitivity evaluation method and an evaluation device for an infrared gas cloud imaging device, belonging to the field of gas detection. Background Art

[0002] Chemical gases are widely used in production and life as raw materials and products. The leakage of chemical gases will not only cause serious safety accidents, but also harm the environment. Rapid gas detection during the production, storage and transportation of chemical gases can timely discover safety hazards, accurately locate gas leakage points and the concentration distribution and diffusion trend of leaked gases in space, and take effective measures to avoid casualties and property losses.

[0003] Existing gas detection technologies generally include infrared imaging gas detection, laser gas detection and chemical gas detection. Since infrared imaging gas detection uses the temperature difference between the gas leak and the surrounding environment to determine whether there is a gas leak in the temperature difference area on the infrared image, it has the advantages of long-distance identification of gas types and concentrations, and display of gas clouds and background spatial distribution. It can realize long-distance, non-contact detection during safe production monitoring and hazardous chemical accident rescue. Therefore, infrared imaging gas detection has a wider application market than traditional laser gas detection and chemical gas detection.

[0004] In order to reduce the occurrence of safety accidents caused by untimely gas leakage detection, it is necessary to evaluate the sensitivity of gas leakage detection.

[0005] The Chinese invention patent application publication document with application publication number CN115900975A discloses an imaging sensitivity evaluation device and evaluation method for SF6 infrared imaging leak detector. The evaluation device includes: an SF6 infrared imaging leak detector to be evaluated; also includes a control module, a leakage source, an automatic gas replenishment system and an error evaluation system; the leakage source includes a trace leakage system and a random leakage system; the control module is used to set the gas leakage rate and the leakage target position point; the trace leakage system can realize the release of the standard trace SF6 gas to the random leakage system according to the gas leakage rate set by the control module; the random leakage system includes an outer experimental box and an inner experimental box; the automatic gas replenishment system is used to replenish the SF6 gas in time when the SF6 gas inside the trace leakage system is exhausted; the error evaluation system is used to display the gas leakage rate of the inner experimental box and the position of the leakage hole corresponding to the leakage target position point. The evaluation method includes: setting the gas leakage rate through the control module, selecting a leakage hole as the leakage target position point, opening the automatic gas replenishment system to use SF6 gas to flush the internal pipeline, and filling the trace leakage system with SF6 gas; the trace leakage system is pushed out and released to the random leakage system according to the gas leakage rate set by the control module; the inner layer experimental box of the random leakage system can be opened according to the solenoid valve on the leakage hole corresponding to the leakage target position point set by the control module; regularly checking the SF6 gas content inside the trace leakage system, and the automatic gas replenishment system replenishes SF6 in time when the SF6 gas inside the trace leakage system is exhausted. F6 gas; sensitivity evaluation step, including the following sub-steps: setting the leakage rate error threshold and the leakage target position error threshold; displaying the gas leakage rate and leakage target position point of the inner test box, and obtaining the gas leakage rate and leakage target position point measured by the SF6 infrared imaging leak detector in the inner test box to calculate the leakage rate error and leakage target position error respectively; comparing the leakage rate error and the leakage rate error threshold, and comparing the leakage target position error and the leakage target position error threshold; if the leakage rate error ≤ the leakage rate error threshold and the leakage target position error ≤ the leakage target position error threshold, the sensitivity is high; otherwise, the sensitivity is low. However, the sensitivity evaluation device can only evaluate the sensitivity level, and cannot know the sensitivity value. Summary of the invention

[0006] The purpose of the present invention is to provide a sensitivity evaluation method and evaluation device for an infrared gas cloud imaging device, so as to solve the problem in the prior art that the infrared gas cloud imaging device cannot know the sensitivity value for the detected gas. To achieve the above purpose, the scheme of the present invention includes: A sensitivity evaluation method of an infrared gas-cloud imaging device of the present invention comprises the following steps: Under certain temperature conditions, the same type of gases to be tested with different concentration gradients pass through the gas restraint tube of preset length in order of concentration from small to large; The gas cloud spectrum camera sequentially captures the spectrum images of the gas to be tested with different concentration gradients in the gas confinement tube and determines whether there is a leak based on the spectrum images; If there is a leak, the sensitivity of the infrared gas cloud imaging device is determined according to the concentration of the gas to be measured corresponding to the leak.

[0007] Furthermore, the sensitivity is equal to the product of the concentration of the gas to be measured and the length of the gas confinement tube.

[0008] Further, after testing the gases with different concentration gradients, if no leakage is found, a longer gas restraint tube is replaced; After the gas restraint tube is replaced, the gases to be tested with different concentration gradients are sequentially passed through the replaced gas restraint tube in order from small to large concentrations for testing.

[0009] Further, after the longest gas restraint tube is replaced, if no leakage is found, the concentration of the gas to be tested is increased; The gas to be tested with increased concentration passes through the gas restraint tubes arranged from short to long in sequence for testing.

[0010] Furthermore, the gas cloud spectrum camera uploads the spectrum image to the computer, and the computer compares the spectrum image with the spectrum image of the gas without leakage; If the spectral image is not similar to the spectral image of the gas without leakage, it is determined that there is leakage.

[0011] Furthermore, before the gas to be tested with the next concentration gradient enters the gas confinement tube, the gas confinement tube is first filled with non-interference gas.

[0012] A sensitivity evaluation device for an infrared gas cloud imaging device of the present invention comprises: a plurality of bottles for containing the same type of gas to be inspected with different concentration gradients, a gas switching device and a gas restraint tube; Each inspected gas cylinder is respectively connected to the corresponding input interface of the gas switching device; the output interface of the gas switching device is connected to the opening on the wall of the gas restraint tube, and the gas switching device is used to connect the input interface with the output interface in sequence.

[0013] Furthermore, it also includes: a standard gas bottle connected to an input interface of the gas switching device, which is used to output interference-free gas to the gas restraint tube before the next concentration gradient of the gas to be tested enters the gas restraint tube.

[0014] Furthermore, it also includes: a temperature-adjustable constant-temperature black body serving as an imaging background of a gas cloud spectrum camera in the infrared gas cloud imaging device to be measured; Thermostatic blackbodies with adjustable temperature are used to provide different temperature conditions.

[0015] Furthermore, the output interface of the gas switching device and the opening on the tube wall of the gas restraint tube are connected via a ventilation tube; The ventilation pipe is provided with a gas flow meter for measuring and adjusting the gas flow rate in the ventilation pipe.

[0016] The beneficial effects of the present invention are as follows: as a pioneering invention, the present invention provides a sensitivity evaluation method and an evaluation device for an infrared gas cloud imaging device, wherein the evaluation method uses a control variable method to allow the same type of test gases with different concentration gradients to pass through a gas confinement tube of a preset length in order of concentration from small to large under certain temperature conditions; a gas cloud spectrum camera sequentially captures spectral images of the test gases with different concentration gradients in the gas confinement tube and determines whether there is a leak based on the spectral images; since the test gases enter the gas confinement tube in order of concentration from small to large, if there is a leak, the leakage amount is the smallest, so the sensitivity of the infrared gas cloud imaging device determined based on the concentration of the test gas corresponding to the leak is the smallest; the present invention can determine the sensitivity of the infrared gas cloud imaging device based on the concentration of the test gas corresponding to the leak, and the operation is simple and easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic flow chart of a sensitivity evaluation method of an infrared gas cloud imaging device provided by an embodiment of the present invention; Figure 2 It is a structural schematic diagram of a sensitivity evaluation device of an infrared gas cloud imaging device provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0019] The idea of ​​the present invention is to use a control variable method to allow the same type of test gases with different concentration gradients to pass through a gas confinement tube of a preset length in order of concentration from small to large under certain temperature conditions; a gas cloud spectrum camera sequentially captures spectral images of the test gases with different concentration gradients in the gas confinement tube and determines whether there is a leak based on the spectral images; since the test gases enter the gas confinement tube in order of concentration from small to large, if there is a leak, the leakage amount is the smallest, so the sensitivity of the infrared gas cloud imaging device determined according to the concentration of the test gas corresponding to the leak is the smallest; the sensitivity of the infrared gas cloud imaging device can be determined by the concentration of the test gas corresponding to the leak, and the operation is simple and easy to implement.

[0020] An embodiment of a sensitivity evaluation method for an infrared gas cloud imaging device: Figure 1FIG. 1 is a flow chart of a sensitivity evaluation method for an infrared gas cloud imaging device provided by an embodiment of the present invention. Figure 1 As shown, the evaluation method includes the following steps: S101, under certain temperature conditions, the same type of gases to be tested with different concentration gradients pass through a gas restraint tube of preset length in order of concentration from small to large.

[0021] The type of the gas to be tested may be methane, sulfur hexafluoride, ammonia, etc., and the present invention does not specifically limit this. The following explanation will be given by taking methane as an example of the gas to be tested.

[0022] Among them, the concentration of the same type of gas to be tested can be 0.5%, 1%, 2%, 10%, etc., which can be set according to actual conditions. The present invention does not make any special limitation on this. The following uses the concentration of the same type of gas to be tested of 0.5%, 1%, 2% and 10% as an example for exemplary description.

[0023] As an optional implementation, the temperature condition is provided by a temperature-adjustable constant-temperature black body, and the temperature-adjustable constant-temperature black body serves as the imaging background of the gas cloud spectrum camera.

[0024] Among them, the adjustable temperature constant temperature black body 80 can provide a variety of temperature test conditions, such as high temperature environment, normal temperature environment and low temperature environment, to determine the sensitivity S of the infrared gas cloud imaging device in different temperature environments. Among them, the high temperature environment can be 30 degrees Celsius (℃), or 35℃, etc., which can be adjusted according to actual conditions, and the present invention does not make special restrictions on this; the normal temperature environment can be 20℃, or 25℃, etc., which can be adjusted according to actual conditions, and the present invention does not make special restrictions on this; the low temperature environment can be 0℃, 5℃, 10℃, or 15℃, etc., which can be adjusted according to actual conditions, and the present invention does not make special restrictions on this. The following takes the high temperature environment of 30℃, the normal temperature environment of 20℃, and the low temperature environment of 0℃ as an example for exemplary description.

[0025] In order to reduce interference factors, as an optional implementation, before the gases to be tested of the same type but different concentration gradients pass through the gas confinement tube 50 of a preset length in order from small to large concentrations, the gas confinement tube 50 is first filled with non-interference gas; before measuring the next concentration of the liquid to be tested, the gas confinement tube 50 is also first filled with non-interference gas.

[0026] The non-interference gas may be air that meets the standard atmospheric pressure, or may be standard nitrogen, etc. The present invention does not specifically limit this. The following explanation will be given by taking the non-interference gas being standard nitrogen as an example.

[0027] In order to reduce interference factors, facilitate the gas monitoring time window to capture the difference between frames, and improve the accuracy of sensitivity evaluation, as an optional implementation, whether it is non-interference gas or test gas, each time it enters the gas confinement tube, it needs to last for a period of time. The duration t1 is the time t1 that the test gas fills the gas confinement tube. full The purpose of such rapid switching back and forth is to simulate the actual working environment of gas leakage.

[0028] Among them, the time t that the gas to be tested fills the gas confinement tube is full It depends on the volume V of the gas confinement tube and the flow rate f of the gas to be measured in the ventilation tube. Specifically, t full =V / f.

[0029] As an optional implementation, the flow rate f of the gas to be measured in the ventilation pipe can be obtained by a gas flow meter.

[0030] As an optional implementation, the same type of gases with different concentration gradients can be directly passed through a gas confinement tube of a preset length in order of concentration from small to large. As another optional implementation, the same type of gases with different concentration gradients can be passed through a gas confinement tube of a preset length in order of concentration from small to large through a gas switching device. The following is an example of gases with different concentration gradients passing through a gas confinement tube of a preset length in order of concentration from small to large through a gas switching device.

[0031] S102 , the gas cloud spectrum camera sequentially captures spectrum images of the gas to be tested with different concentration gradients in the gas confinement tube and determines whether there is a leak based on the spectrum images of the gas to be tested.

[0032] As an optional implementation, the gas cloud spectrum camera can directly determine whether there is a leak based on the spectrum image of the gas to be tested; as another optional implementation, the gas cloud spectrum camera can upload the spectrum image to a computer, and the computer compares the spectrum image of the gas to be tested with the preset spectrum image of the gas without leakage to determine whether there is a leak. In order to obtain more accurate sensitivity, the following example will be used as an example in which the gas cloud spectrum camera can upload the spectrum image to a computer, and the computer compares the spectrum image of the gas to be tested with the spectrum image of the gas without leakage to determine whether there is a leak.

[0033] As an optional implementation, the gas cloud spectrum camera can upload the spectrum image to the computer through wireless communication such as WiFi or Bluetooth; as another optional implementation, the gas cloud spectrum camera can also upload the spectrum image to the computer through wired communication using a communication cable. In order to reduce costs, the following example uses the gas cloud spectrum camera uploading the spectrum image to the computer through wired communication using a communication cable as an example for exemplary description.

[0034] There are multiple preset gas non-leakage images, each corresponding to a type of gas to be tested, that is, the computer will automatically call up a gas non-leakage spectrum image of the same type as the gas to be tested and compare it with the spectrum image of the gas to be tested.

[0035] The frequency of capturing the spectrum image of the gas to be tested with different concentration gradients in the gas confinement tube by the gas cloud spectrum camera is f. rame , according to the capture frequency f rame and the adjustment coefficient N determine the size of the gas monitoring time window t switch . Specifically, t switch =N / f rame Among them, the capture frequency f rame It is related to the characteristics of the gas cloud spectrometer. Different gas cloud spectrometers have different capture frequencies. The adjustment coefficient N is related to the capture frequency f. rame and the time t that the gas to be tested fills the gas confinement tube full In this regard, the embodiment of the present invention takes the adjustment coefficient N as 20 as an example for illustrative description.

[0036] S103: If there is a leak, determine the sensitivity S of the infrared gas cloud imaging device according to the concentration of the gas to be measured corresponding to the leak.

[0037] Specifically, when the computer compares the spectral image of the gas to be tested and finds that it is not similar to the preset spectral image of the gas without leakage, it is judged that there is a leakage, and the sensitivity S can be calculated at this time; the sensitivity S is equal to the minimum value of the product of the concentration g of the gas to be tested and the length L of the gas restraint tube when the gas leakage can be detected.

[0038] After executing steps S101 to S103 , if no gas leakage is detected, as an optional implementation, step S104 (not shown) may be executed, ie, the length of the gas restraint tube may be replaced.

[0039] S104. Replace the length of the gas restraint tube.

[0040] The length of the replaced gas restraint tube is greater than the length of the gas restraint tube preset at the beginning. The embodiment of the present invention provides three lengths of gas restraint tubes, namely, a gas restraint tube with a first length L1, a gas restraint tube with a second length L2, and a gas restraint tube with a third length L3. It can be understood that in actual application, the length of the gas restraint tube can be longer, and the present invention does not specifically limit this.

[0041] The first length L1 is the longest, the third length L3 is the shortest, and the second length L2 is between the first length L1 and the third length L3; the length of the gas restraint tube initially preset is the third length L3.

[0042] Since the desired sensitivity is a minimum value, based on the principle of the control variable method, the length of the gas restraint tube after replacement is greater than the length of the gas restraint tube before replacement.

[0043] After the length of the gas restraint tube is replaced, the same type of gases to be tested with different concentration gradients pass through the replaced gas restraint tube in order of concentration from small to large. The test process is similar to the above steps S101 to S103 and will not be repeated here.

[0044] After the longest gas restraint tube is replaced, if no gas leakage is detected, as another optional implementation, step S105 (not shown) may be performed, ie, increasing the concentration of the gas to be tested.

[0045] S105. Increase the concentration of the gas to be measured.

[0046] Since the desired sensitivity is the minimum value, based on the principle of the controlled variable method, the gas to be tested with increased concentration is passed through the gas restraint tubes arranged from short to long in sequence. The test process is similar to the above steps S101 to S103 and will not be repeated here.

[0047] It is understandable that the concentration of the gas to be tested may be increased multiple times. After each concentration measurement of the gas to be tested, if no leakage is found, the concentration of the gas to be tested may be increased further until the sensitivity is obtained.

[0048] The following is an example of testing the sensitivity S=10%*L1 of the infrared cloud imaging device in testing methane gas leakage in a low temperature environment.

[0049] When the infrared cloud imaging device needs to be tested for the sensitivity of methane gas leakage in a low temperature environment: initially, the length of the gas restraint tube is the third length L3, and the temperature of the adjustable constant temperature black body is set to 0°C.

[0050] After the temperature of the adjustable thermostatic black body is stabilized, the gas switching device allows nitrogen to fill the gas confinement tube with a third length L3; after stabilization, the gas switching device allows methane with a concentration of 0.5% to enter the gas confinement tube with a third length L3 for a preset time; the gas cloud spectrum camera captures the spectral image of the methane gas with a concentration of 0.5% in the gas confinement tube and uploads it to the computer; the computer compares the spectral image of the methane gas with a concentration of 0.5% with the preset spectral image of the methane gas without leakage.

[0051] After the similarity is found with the preset spectral image of gas without leakage, it is considered that there is no gas leakage, and the gas switching device allows nitrogen to enter the gas confinement tube with a length of the third length L3; after the preset time, methane with a concentration of 1% is allowed to enter the gas confinement tube with a length of the third length L3 and continue for the preset time; the gas cloud spectrum camera captures the spectral image of the methane gas with a concentration of 1% in the gas confinement tube and uploads it to the computer; the computer compares the spectral image of the methane gas with a concentration of 1% with the preset spectral image of the methane gas without leakage.

[0052] After comparison, it is found that there is similarity with the preset gas non-leakage spectral image, and it is considered that there is no gas leakage, the gas switching device allows nitrogen to enter the gas confinement tube with a length of the third length L3; after continuing for a preset time, methane with a concentration of 2% is allowed to enter the gas confinement tube with a length of the third length L3 and continue for a preset time; the gas cloud spectrum camera captures the spectral image of the methane gas with a concentration of 2% in the gas confinement tube and uploads it to the computer; the computer compares the spectral image of the methane gas with a concentration of 2% with the preset gas non-leakage spectral image of methane gas.

[0053] After the similarity is found with the preset spectral image of gas without leakage, it is considered that there is no gas leakage, and the gas switching device allows nitrogen to enter the gas confinement tube with a length of the third length L3; after the preset time, methane with a concentration of 10% is allowed to enter the gas confinement tube with a length of the third length L3 and continue for the preset time; the gas cloud spectrum camera captures the spectral image of the methane gas with a concentration of 10% in the gas confinement tube and uploads it to the computer; the computer compares the spectral image of the methane gas with a concentration of 10% with the preset spectral image of the methane gas without leakage.

[0054] If there is still similarity, the length of the gas restraint tube is changed to make the length of the gas restraint tube the second length L2. When the length of the gas restraint tube is the second length L2, the process of determining whether methane gas is leaked is similar to the above process when the length of the gas restraint tube is the third length L3, and will not be repeated here.

[0055] When the temperature is 0°C and the length of the gas restraint tube is the second length L2, if there is still similarity after measuring methane with concentrations of 0.5%, 1%, 2% and 10%, continue to change the length of the gas restraint tube to the first length L1.

[0056] After the temperature of the adjustable thermostatic black body is stabilized, the gas switching device allows nitrogen to fill the gas confinement tube with a first length L1; after stabilization, the gas switching device allows methane with a concentration of 0.5% to enter the gas confinement tube with a first length L1 for a preset time; the gas cloud spectrum camera captures the spectral image of the methane gas with a concentration of 0.5% in the gas confinement tube and uploads it to the computer; the computer compares the spectral image of the methane gas with a concentration of 0.5% with the preset spectral image of the methane gas without leakage.

[0057] After the similarity is found with the preset spectral image of gas without leakage, it is considered that there is no gas leakage, and the gas switching device allows nitrogen to enter the gas confinement tube with a first length L1; after a preset time, methane with a concentration of 1% is allowed to enter the gas confinement tube with a first length L1 and continue for a preset time; the gas cloud spectrum camera captures the spectral image of methane gas with a concentration of 1% in the gas confinement tube and uploads it to the computer; the computer compares the spectral image of methane gas with a concentration of 1% with the preset spectral image of methane gas without leakage.

[0058] After the similarity is found with the preset spectral image of gas without leakage, it is considered that there is no gas leakage, and the gas switching device allows nitrogen to enter the gas confinement tube with a first length L1; after the preset time, methane with a concentration of 2% is allowed to enter the gas confinement tube with a first length L1 and continue for the preset time; the gas cloud spectrum camera captures the spectral image of the methane gas with a concentration of 2% in the gas confinement tube and uploads it to the computer; the computer compares the spectral image of the methane gas with a concentration of 2% with the preset spectral image of the methane gas without leakage.

[0059] After the comparison shows similarity with the preset spectral image of no gas leakage, it is considered that there is no gas leakage, and the gas switching device allows nitrogen to enter the gas confinement tube with a first length L1; after a preset time, methane with a concentration of 10% is allowed to enter the gas confinement tube with a first length L1 and continue for a preset time; the gas cloud spectrum camera captures the spectral image of methane gas with a concentration of 10% in the gas confinement tube and uploads it to the computer; the computer compares the spectral image of methane gas with a concentration of 10% with the preset spectral image of no gas leakage; after the comparison shows no similarity with the preset spectral image of no gas leakage, at this time, the sensitivity of the infrared imaging device to methane leakage detection under a temperature environment of 0°C is S=10%*L1.

[0060] It should be noted that, after those skilled in the art know the embodiments of the method for evaluating the sensitivity of the infrared gas cloud imaging device for methane gas leakage in a low temperature (0°C) environment, they can imagine how to evaluate the sensitivity in other temperature environments or other types of gases to be tested, which will not be repeated here.

[0061] A sensitivity evaluation method for an infrared gas cloud imaging device provided in an embodiment of the present invention uses a control variable method to allow the same type of test gases with different concentration gradients to pass through a gas confinement tube of a preset length in order of concentration from small to large under certain temperature conditions; a gas cloud spectrum camera sequentially captures spectral images of the test gases with different concentration gradients in the gas confinement tube and determines whether there is a leak based on the spectral images; since the test gases enter the gas confinement tube in order of concentration from small to large, if there is a leak, the leakage amount is the smallest, so the sensitivity of the infrared gas cloud imaging device determined based on the concentration of the test gas corresponding to the leak is the smallest; the sensitivity of the infrared gas cloud imaging device can be determined by the concentration of the test gas corresponding to the leak, and the operation is simple and easy to implement.

[0062] An embodiment of a sensitivity evaluation device for an infrared gas cloud imaging device: Figure 2 is a schematic diagram of a sensitivity evaluation device for an infrared gas cloud imaging device provided by an embodiment of the present invention. Figure 2 As shown, the sensitivity evaluation device includes: a plurality of gas cylinders 20 for containing the same type of gas under test with different concentration gradients, a gas switching device 30 and a gas restraint tube 50; each gas cylinder under test is respectively connected to the corresponding input interface of the gas switching device 30; the output interface of the gas switching device 30 is connected to the opening on the tube wall of the gas restraint tube 50, and the gas switching device 30 is used to connect the input interface with the output interface in sequence.

[0063] As another optional implementation, the output interface of the gas switching device 30 and the opening on the tube wall of the gas restraint tube 50 are connected via a ventilation tube 40 .

[0064] The ventilation pipes 40 may include several ones, each corresponding to the output of the gas in a gas cylinder; as another optional embodiment, the ventilation pipe 40 may include one, and one ventilation pipe outputs different gases. In order to reduce the complexity of the device, the ventilation pipe 40 may include one as an example for exemplary description.

[0065] In order to measure and control the flow rate of the gas in the ventilation pipe 40 , as an optional implementation, a gas flow meter 60 is provided on the ventilation pipe 40 .

[0066] The present invention does not specifically limit the number of gas cylinders to be inspected. In order to facilitate the description of the principle, the following description will be made by taking the case where the number of gas cylinders to be inspected is 4, namely, gas cylinder B, gas cylinder C, gas cylinder D and gas cylinder E as an example.

[0067] The present invention does not specifically limit the type of gas in the gas bottle to be tested, and the gas may be methane, sulfur hexafluoride, ammonia, etc. For the convenience of describing the principle, the following explanation is made by taking the gas type in the gas bottle to be tested as methane as an example. The gas type in the gas bottle to be tested is also the type of the gas to be tested.

[0068] Among them, the setting of different concentrations of the same type of gas to be tested in the gas bottle to be tested can be set according to actual conditions, and the present invention does not specifically limit this, and can be 0.5%, 1%, 2%, 10%, 15%, etc. In order to facilitate the description of the principle, the following takes the concentration of the same type of gas to be tested as 0.5%, 1%, 2% and 10% as an example for exemplary description.

[0069] That is, gas cylinder B is filled with methane with a concentration of 0.5%, gas cylinder C is filled with methane with a concentration of 1%, gas cylinder D is filled with methane with a concentration of 2%, and gas cylinder E is filled with methane with a concentration of 10%.

[0070] Among them, the length of the gas restraint tube 50 is multiple, and the number of lengths of the gas restraint tube 50 can be set according to actual conditions, and the present invention does not specifically limit this. In order to facilitate the description of the principle, the following takes the gas restraint tube 50 having three lengths, namely the first length L1, the second length L2 and the third length L3, as an example for a time description. Among them, the first length L1 is the longest, the third length L3 is the shortest, and the second length L2 is between the first length L1 and the third length L3. When the bottom area of ​​the gas restraint tube is constant, different lengths of the gas restraint tube will result in different volumes of the gas restraint tube.

[0071] In order to reduce interference factors, as an optional implementation, the sensitivity evaluation device of the infrared gas cloud imaging device provided in an embodiment of the present invention also includes: a standard gas bottle 10 connected to an input interface of the gas switching device 30, used to output interference-free gas to the gas confinement tube 50 before the next concentration gradient of the gas to be tested enters the gas confinement tube 50.

[0072] The standard gas cylinder 10 may be one or more, and the present invention does not specifically limit this. In order to simplify the device structure, the standard gas cylinder 10 including one gas cylinder, namely, gas cylinder A, is taken as an example for exemplary description.

[0073] The non-interference gas may be standard air or standard nitrogen, etc., and the present invention does not specifically limit this. In order to facilitate the explanation of the principle, the non-interference gas is standard nitrogen as an example for exemplary explanation, that is, the gas bottle A is filled with standard nitrogen.

[0074] In order to reduce interference factors, facilitate the gas monitoring time window to capture the difference between frames, and improve the accuracy of sensitivity evaluation, as an optional implementation, no matter whether it is non-interference gas or test gas, each time it enters the gas restraint tube 50, it needs to last for a period of time. The duration t1 is the time t1 that the test gas fills the gas restraint tube 50. full The purpose of such rapid switching back and forth is to simulate the actual working environment of gas leakage.

[0075] The time t that the gas to be tested fills the gas restraint tube 50 is full It depends on the volume V of the gas restraint tube 50 and the flow rate f of the gas to be measured in the ventilation tube 40. Specifically, t full =V / f.

[0076] As an optional implementation, the flow rate f of the gas to be measured in the ventilation pipe 40 can be obtained by a gas flow meter 60 .

[0077] In order to make the imaging of the gas cloud spectrum camera in the infrared gas cloud imaging device to be tested more obvious and easier to observe, as an optional implementation, the sensitivity evaluation device of the infrared gas cloud imaging device provided in the embodiment of the present invention also includes: an adjustable temperature constant temperature black body 80 serving as the imaging background of the gas cloud spectrum camera in the infrared gas cloud imaging device to be tested; the adjustable temperature constant temperature black body 80 is used to provide different temperature conditions.

[0078] Among them, the adjustable temperature constant temperature black body 80 can provide a variety of temperature test conditions, such as high temperature environment, normal temperature environment and low temperature environment. Among them, the high temperature environment can be 30 degrees Celsius (℃), or 35℃, etc., which can be adjusted according to actual conditions, and the present invention does not make special restrictions on this; the normal temperature environment can be 20℃, or 25℃, etc., which can be adjusted according to actual conditions, and the present invention does not make special restrictions on this; the low temperature environment can be 0℃, 5℃, 10℃, or 15℃, etc., which can be adjusted according to actual conditions, and the present invention does not make special restrictions on this. The following takes the high temperature environment of 30℃, the normal temperature environment of 20℃, and the low temperature environment of 0℃ as an example for exemplary description.

[0079] The infrared gas cloud imaging device to be tested at least includes a gas cloud spectrum camera 70. The gas cloud spectrum camera 70 is used to sequentially capture the spectrum images of the gas to be tested with different concentration gradients in the gas confinement tube 50 and determine whether there is a leak according to the spectrum images of the gas to be tested; if there is a leak, the sensitivity of the infrared gas cloud imaging device is determined according to the concentration of the gas to be tested corresponding to the leak.

[0080] In order to improve the accuracy of leak judgment, as an optional implementation, the infrared gas cloud imaging device to be tested also includes a computer.

[0081] The gas cloud spectrum camera 70 uploads the spectrum image of the gas to be tested to the computer, and the computer compares the spectrum image with the spectrum image of the gas without leakage; if the spectrum image is not similar to the spectrum image of the gas without leakage, it is determined that there is a leak.

[0082] As an optional implementation, the gas cloud spectrum camera 70 can upload the spectrum image to the computer through wireless communication such as WiFi or Bluetooth; as another optional implementation, the gas cloud spectrum camera 70 can also upload the spectrum image to the computer through wired communication of a communication cable. In order to reduce costs, the following example takes the gas cloud spectrum camera 70 uploading the spectrum image to the computer through wired communication of a communication cable as an example for exemplary description.

[0083] There are multiple preset gas non-leakage images, each corresponding to a type of gas to be tested, that is, the computer will automatically call up a gas non-leakage spectrum image of the same type as the gas to be tested and compare it with the spectrum image of the gas to be tested.

[0084] The frequency of capturing the spectrum image of the gas to be tested with different concentration gradients in the gas confinement tube by the gas cloud spectrum camera is f. rame , according to the capture frequency f rame and the adjustment coefficient N determine the size of the gas monitoring time window t switch . Specifically, t switch =N / f rame Among them, the capture frequency f rame It is related to the characteristics of the gas cloud spectrometer. Different gas cloud spectrometers have different capture frequencies. The adjustment coefficient N is related to the capture frequency f. rame and the time t that the gas to be tested fills the gas confinement tube full In this regard, the embodiment of the present invention takes the adjustment coefficient N as 20 as an example for illustrative description.

[0085] The following is an example of testing the sensitivity S=10%*L1 of the infrared cloud imaging device in testing methane gas leakage in a low temperature environment.

[0086] When it is necessary to test the sensitivity of the infrared cloud imaging device to methane gas leakage in a low-temperature environment: the length of the gas restraint tube is the third length L3, the temperature of the adjustable constant-temperature blackbody is set to 0°C, gas cylinder A is filled with nitrogen, gas cylinder B is filled with methane with a concentration of 0.5%, gas cylinder C is filled with methane with a concentration of 1%, gas cylinder D is filled with methane with a concentration of 2%, and gas cylinder E is filled with methane with a concentration of 10%.

[0087] After the temperature of the adjustable thermostatic black body 80 is stabilized, the gas switching device 30 is switched to gas cylinder A to allow nitrogen to fill the gas confinement tube 50; after stabilization, the gas switching device 30 is switched to gas cylinder B to allow methane with a concentration of 0.5% to enter the gas confinement tube 50 for a preset duration; the gas cloud spectrum camera 70 captures the spectral image of the methane gas with a concentration of 0.5% in the gas confinement tube 50 and uploads it to the computer; the computer compares the spectral image of the methane gas with a concentration of 0.5% with the preset spectral image of the gas without leakage.

[0088] After the similarity is found with the preset spectral image of no gas leakage, it is considered that there is no gas leakage, and the gas switching device 30 switches to gas cylinder A to allow nitrogen to enter the gas confinement tube; after a preset time, switch gas cylinder C to allow methane with a concentration of 1% to enter the gas confinement tube and continue for a preset time; the gas cloud spectrum camera 70 captures the spectral image of the methane gas with a concentration of 1% in the gas confinement tube 50 and uploads it to the computer; the computer compares the spectral image of the methane gas with a concentration of 1% with the preset spectral image of no gas leakage.

[0089] After the similarity is found with the preset spectral image of no gas leakage, it is considered that there is no gas leakage, and the gas switching device 30 switches to gas cylinder A to allow nitrogen to enter the gas confinement tube; after a preset time, switch to gas cylinder D to allow methane with a concentration of 2% to enter the gas confinement tube and continue for a preset time; the gas cloud spectrum camera 70 captures the spectral image of the methane gas with a concentration of 2% in the gas confinement tube 50 and uploads it to the computer; the computer compares the spectral image of the methane gas with a concentration of 2% with the preset spectral image of no gas leakage.

[0090] After the similarity is found with the preset spectral image of no gas leakage, it is considered that there is no gas leakage, and the gas switching device 30 switches to gas cylinder A to allow nitrogen to enter the gas confinement tube; after a preset time, switch gas cylinder E to allow methane with a concentration of 10% to enter the gas confinement tube and continue for a preset time; the gas cloud spectrum camera 70 captures the spectral image of the methane gas with a concentration of 10% in the gas confinement tube 50 and uploads it to the computer; the computer compares the spectral image of the methane gas with a concentration of 10% with the preset spectral image of no gas leakage.

[0091] If there is still similarity, the length of the gas restraint tube is changed to make the length of the gas restraint tube the second length L2. When the length of the gas restraint tube is the second length L2, the process of determining whether methane gas is leaked is similar to the above process when the length of the gas restraint tube is the third length L3, and will not be repeated here.

[0092] When the temperature is 0°C and the length of the gas restraint tube is the second length L2, if there is still no similarity after measuring methane with concentrations of 0.5%, 1%, 2% and 10%, the length of the gas restraint tube is changed to the first length L1.

[0093] After the temperature of the adjustable thermostatic black body 80 is stabilized, the gas switching device 30 is switched to gas cylinder A to allow nitrogen to fill the gas confinement tube 50; after stabilization, the gas switching device 30 is switched to gas cylinder B to allow methane with a concentration of 0.5% to enter the gas confinement tube 50 for a preset duration; the gas cloud spectrum camera 70 captures the spectral image of the methane gas with a concentration of 0.5% in the gas confinement tube 50 and uploads it to the computer; the computer compares the spectral image of the methane gas with a concentration of 0.5% with the preset spectral image of the gas without leakage.

[0094] After the similarity is found with the preset spectral image of no gas leakage, it is considered that there is no gas leakage, and the gas switching device 30 switches to gas cylinder A to allow nitrogen to enter the gas confinement tube; after a preset time, switch gas cylinder C to allow methane with a concentration of 1% to enter the gas confinement tube and continue for a preset time; the gas cloud spectrum camera 70 captures the spectral image of the methane gas with a concentration of 1% in the gas confinement tube 50 and uploads it to the computer; the computer compares the spectral image of the methane gas with a concentration of 1% with the preset spectral image of no gas leakage.

[0095] After the similarity is found with the preset spectral image of no gas leakage, it is considered that there is no gas leakage, and the gas switching device 30 switches to gas cylinder A to allow nitrogen to enter the gas confinement tube; after a preset time, switch to gas cylinder D to allow methane with a concentration of 2% to enter the gas confinement tube and continue for a preset time; the gas cloud spectrum camera 70 captures the spectral image of the methane gas with a concentration of 2% in the gas confinement tube 50 and uploads it to the computer; the computer compares the spectral image of the methane gas with a concentration of 2% with the preset spectral image of no gas leakage.

[0096] After the comparison shows similarity with the preset spectral image of no gas leakage, it is considered that there is no gas leakage, and the gas switching device 30 switches to gas cylinder A to allow nitrogen to enter the gas restraint tube 50; after a preset time, switch gas cylinder E to allow methane with a concentration of 10% to enter the gas restraint tube 50 and continue for a preset time; the gas cloud spectrum camera 70 captures the spectral image of methane gas with a concentration of 10% in the gas restraint tube 50 and uploads it to the computer; the computer compares the spectral image of methane gas with a concentration of 10% with the preset spectral image of no gas leakage; after the comparison shows no similarity with the preset spectral image of no gas leakage, at this time, the sensitivity of the infrared imaging device to methane leakage detection in a temperature environment of 0°C is S=10%*L1.

[0097] It should be noted that, after those skilled in the art know the embodiments of the method for evaluating the sensitivity of the infrared gas cloud imaging device for methane gas leakage in a low temperature (0°C) environment, they can imagine how to evaluate the sensitivity in other temperature environments or other types of gases to be tested, which will not be repeated here.

[0098] A sensitivity evaluation device for an infrared gas-cloud imaging device provided in an embodiment of the present invention can achieve the same beneficial effects as the sensitivity evaluation method for an infrared gas-cloud imaging device described above, which will not be described in detail herein.

Claims

1. A sensitivity evaluation method for an infrared gas cloud imaging device, characterized in that: The steps include: Under certain temperature conditions, the same type of gases to be tested with different concentration gradients pass through the gas restraint tube of preset length in order of concentration from small to large; The gas cloud spectrum camera sequentially captures spectrum images of the gas to be tested with different concentration gradients in the gas confinement tube and determines whether there is a leak based on the spectrum images; If there is a leak, the sensitivity of the infrared gas cloud imaging device is determined according to the concentration of the gas to be measured corresponding to the leak.

2. The sensitivity evaluation method of the infrared gas cloud imaging device according to claim 1, characterized in that: The sensitivity is equal to the product of the concentration of the gas to be measured and the length of the gas confinement tube.

3. The sensitivity evaluation method of the infrared gas cloud imaging device according to claim 2, characterized in that: After the gas to be tested with different concentration gradients is tested and no leakage is found, a longer gas restraint tube is replaced; After the gas restraint tube is replaced, the gases to be tested with different concentration gradients are sequentially passed through the replaced gas restraint tube in order from small to large concentrations for testing.

4. The sensitivity evaluation method of the infrared gas cloud imaging device according to claim 3 is characterized in that: After the longest gas restraint tube is replaced and no leakage is found, increase the concentration of the gas to be tested; The gas to be tested with increased concentration passes through the gas restraint tubes arranged from short to long in sequence for testing.

5. The sensitivity evaluation method of the infrared gas cloud imaging device according to claim 1, characterized in that: The gas cloud spectrum camera uploads the spectrum image to a computer, and the computer compares the spectrum image with a spectrum image without gas leakage; If the spectral image has no similarity with the spectral image of no gas leakage, it is determined that there is leakage.

6. The sensitivity evaluation method of the infrared gas cloud imaging device according to claim 1 or 2, characterized in that: Before the gas to be tested with the next concentration gradient enters the gas confinement tube, the gas confinement tube is first filled with non-interference gas.

7. A sensitivity evaluation device for an infrared gas cloud imaging device, characterized in that: include: Several bottles for containing the same type of gas under test with different concentration gradients, gas switching devices and gas restraint tubes; Each of the inspected gas cylinders is respectively connected to the corresponding input interface of the gas switching device; the output interface of the gas switching device is connected to the opening on the tube wall of the gas restraint tube, and the gas switching device is used to connect the input interface with the output interface in sequence.

8. The sensitivity evaluation device of the infrared gas cloud imaging device according to claim 7, characterized in that: Also includes: The standard gas bottle is connected to an input interface of the gas switching device and is used to output a non-interfering gas to the gas restraint tube before the next concentration gradient of the gas to be tested enters the gas restraint tube.

9. The sensitivity evaluation device of the infrared gas cloud imaging device according to claim 7, characterized in that: Also includes: A temperature-adjustable constant-temperature black body used as the imaging background of the gas cloud spectrum camera in the infrared gas cloud imaging device to be measured; The adjustable temperature constant temperature black body is used to provide different temperature conditions.

10. The sensitivity evaluation device of the infrared gas cloud imaging device according to claim 7, characterized in that: The output interface of the gas switching device and the opening on the tube wall of the gas restraint tube are connected via a ventilation tube; The ventilation pipe is provided with a gas flow meter for measuring and adjusting the gas flow rate in the ventilation pipe.

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