Laser combustible gas detector calibration device and method

Abstract

The invention discloses a laser combustible gas detector calibration device and method. The laser combustible gas detector calibration device comprises a standard gas chamber, the standard gas chamber comprises a gas chamber cylinder, an inlet valve, an outlet valve, a polytetrafluoroethylene light-transmitting film, a light shield and a light shield plate; through holes are respectively formed in the circumferential surfaces, close to the two ends, of the air chamber cylinder; the inlet valve and the outlet valve are respectively communicated with the two through holes; the two ends of the air chamber cylinder are sealed through polytetrafluoroethylene light-transmitting films, and a shading plate is detachably connected to the outer portion of one polytetrafluoroethylene light-transmitting film. The measurement performance of the laser combustible gas detector can be calibrated.

Description

Technical Field

[0001] The invention belongs to the field of gas detectors and relates to a laser combustible gas detector calibration device and method. Background Art

[0002] Laser combustible gas detector is a device that uses infrared sensors to detect alkane combustible gases in the field environment through the absorption principle of infrared light sources. It is suitable for leak detection of gas transmission and distribution pipelines, indoor gas pipelines, overhead pipelines, risers or pipelines distributed in narrow spaces.

[0003] Laser combustible gas detectors can quickly and accurately detect gas leaks within a distance of 60 meters or even longer. Laser combustible gas detectors can accurately monitor the concentration of combustible gas at any time and anywhere without the staff entering the site. On the premise of monitoring the safe concentration of combustible gas, they can enter the site for operation, making inspections in places that were previously inaccessible or difficult to reach possible, meeting the urgent needs of oil field production development. However, the existing laser combustible gas detectors do not have corresponding calibration devices, and the country has not issued corresponding calibration methods for laser combustible gas detectors. Summary of the invention

[0004] The purpose of the present invention is to overcome the above-mentioned shortcomings of the prior art and provide a laser combustible gas detector calibration device and method, which can calibrate the measurement performance of the laser combustible gas detector.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A laser combustible gas detector calibration device includes a standard gas chamber;

[0007] The standard gas chamber includes a gas chamber cylinder, an inlet valve, an outlet valve, a polytetrafluoroethylene light-transmitting film, a light shield and a light shield;

[0008] Through holes are respectively opened on the circumference of the air chamber cylinder near both ends, and the inlet valve and the outlet valve are respectively connected to the two through holes; both ends of the air chamber cylinder are sealed with polytetrafluoroethylene transparent films, and a shading plate is detachably connected to the outside of one of the polytetrafluoroethylene transparent films.

[0009] Preferably, a fixing ring is respectively provided on the circumferential surface of the air chamber cylinder near both ends.

[0010] Preferably, the standard air chamber is connected to a bracket.

[0011] Furthermore, a fixed base is provided at the axial center position of the peripheral surface of the air chamber cylinder, and an internal thread is provided on the fixed base;

[0012] The bracket includes a support rod and a triangular bracket. External threads are arranged on the top and near the bottom of the support rod, and the fixed base is connected to the external threads on the top of the support rod; a fixed thread sleeve is arranged on the top of the triangular bracket, which is nested in the bottom of the support rod and is threadedly connected to the support rod near the bottom.

[0013] Furthermore, the support rod is a telescopic rod.

[0014] Preferably, the two polytetrafluoroethylene light-transmitting films are both covered with light-shielding covers, and the light-shielding plate is detachably connected to the outside of one of the light-shielding covers.

[0015] A laser combustible gas detector calibration method based on the device comprises the following steps: filling clean air into a standard gas chamber, placing the standard gas chamber in a detection beam emitted by the laser combustible gas detector, and adjusting the zero point value of the laser combustible gas detector; filling the standard gas chamber with a gas standard substance of % of the full scale of the laser combustible gas detector, placing the standard gas chamber in a detection beam emitted by the laser combustible gas detector, and adjusting the indication of the laser combustible gas detector; and then respectively filling the standard gas chamber with gas standard substances of 10%, 40% and 60% of the full scale of the laser combustible gas detector, measuring each concentration multiple times, recording the stable indication of the laser combustible gas detector, calculating the indication error of each concentration, and judging whether the error meets the requirement.

[0016] Preferably, a standard gas chamber filled with clean air is placed in the detection beam of the emitting end of the laser combustible gas detector. After adjusting the zero point of the laser combustible gas detector, a standard gas chamber filled with a certain concentration of combustible gas is placed in the detection beam emitted by the laser combustible gas detector, and the stable indication of the laser combustible gas detector is recorded. The standard gas chamber is removed, the laser combustible gas detector is allowed to return to the zero point, and the standard gas chamber is replaced. At the same time, a stopwatch is started. When the indication rises to 90% of the above-mentioned stable indication, the stopwatch is stopped and the time displayed by the stopwatch is recorded. The measurement is repeated multiple times according to the above-mentioned operation method. The arithmetic mean of the multiple measurement results is the response time of the laser combustible gas detector, and whether the response time meets the requirements is judged.

[0017] Preferably, a standard gas chamber filled with a certain concentration of combustible gas and a dimming film are placed in the detection beam emitted by the laser combustible gas detector, with the dimming film located between the emitting end of the laser combustible gas detector and the standard gas chamber, and the laser combustible gas detector is observed to see whether it can monitor normally. If the dimming film is removed and the laser combustible gas detector can automatically or manually return to a normal monitoring state, the light intensity performance of the laser combustible gas detector is considered to be good.

[0018] Preferably, when calibrating a fixed laser combustible gas detector, if you want to detect gas concentrations at multiple points between the transmitting end and the receiving end, hang the standard gas chamber on the track or copper wire between the receiving and transmitting ends through a fixed collar, move the standard gas chamber, detect the measurement accuracy at different distances, and record the test results.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention adopts a standard gas chamber, can pass clean air or combustible gas of different concentrations into the standard gas chamber through an inlet valve and an outlet valve, and puts the standard gas chamber in the detection light beam emitted by the laser combustible gas detector, so that the detection indication error, alarm action value, response time and repeatability of the laser combustible gas detector can be effectively detected and calibrated; and by installing and removing the shading plate, both the fixed laser combustible gas detector and the handheld laser combustible gas detector can be calibrated.

[0021] Furthermore, fixed rings are installed at both ends of the outer wall of the standard gas chamber. If you want to detect the gas concentration at multiple points between the transmitting end and the receiving end, or calibrate the measurement accuracy at different distances, hang the standard gas chamber on the track or copper wire between the receiving and transmitting ends, move the standard gas chamber while recording the test results, and detect the measurement accuracy at different distances.

[0022] Furthermore, the standard gas chamber is fixed on the bracket, and the best channel of the light beam is found by moving and lifting the bracket to ensure stable measurement of the light beam of the laser combustible gas detector.

[0023] Furthermore, the sunshade can be used to block strong sunlight and prevent laser scattering.

[0024] Furthermore, a laser combustible gas detector is used to measure standard gas chambers of multiple concentrations, the stable indication of the laser combustible gas detector is recorded, the indication error of each concentration is calculated, and it is determined whether the error meets the requirements, so that the indication error of the laser combustible gas detector can be measured.

[0025] Furthermore, by repeatedly measuring the same concentration for multiple times and recording the time displayed on the stopwatch, the arithmetic mean of the measurement results is the response time of the laser combustible gas detector. The response time of the laser combustible gas detector can be detected to determine whether the response time meets the requirements.

[0026] Furthermore, a dimming film is used to detect whether the laser combustible gas detector can work normally after the laser is attenuated, and whether the laser combustible gas detector can automatically or manually restore to the normal monitoring state after the laser is normal, so as to determine the light intensity performance of the laser combustible gas detector. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the standard air chamber structure of the present invention;

[0028] Figure 2 It is a schematic diagram of the support structure of the present invention.

[0029] Among them: 1-fixed base; 2-triangular bracket; 3-rotating lock; 4-support rod; 5-anti-slip fixing ring; 6-internal thread; 7-air chamber cylinder; 8-thermal insulation protective layer; 9-internal anti-corrosion coating; 10-inlet valve; 11-outlet valve; 12-polytetrafluoroethylene light-transmitting film; 13-light shield; 14-fixed threaded sleeve; 15-light shielding plate; 16-sealing gasket; 17-fixed collar; 18-standard air chamber. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0031] It should be noted that the words "front", "rear", "left", "right", "up" and "down" used in the following description refer to directions in the drawings, and the words "inside" and "outside" refer to directions toward or away from the geometric center of a specific component, respectively.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0033] This embodiment calibrates a fixed laser combustible gas detector and a handheld laser combustible gas detector.

[0034] The fixed laser combustible gas detector uses the principle of spectral absorption. The transmitting end of the detector sends a beam of infrared light to the receiving end. When there is a detection gas, the infrared light of a specific wavelength in the beam is absorbed by the gas. By comparing the intensity of the infrared light absorbed at the receiving end with the reference infrared light intensity, the concentration of the detection gas can be obtained. The fixed laser combustible gas detector mainly includes a transmitting device, a receiving device and a signal processing circuit device, which can quickly and accurately detect gas leaks within a distance of 60 meters or even longer.

[0035] The handheld laser methane detector has a built-in transmitter and a receiver. When in use, the laser emitted by the transmitter is irradiated by the standard gas to the shading plate 15 made of PP material, and then reflected back and received by the receiver, so as to detect the gas concentration.

[0036] like Figure 1 As shown, the laser combustible gas detector calibration device of the present invention includes a standard gas chamber 18.

[0037] The standard air chamber 18 includes a fixed base 1, an air chamber cylinder 7, a heat insulation protective layer 8, an internal anti-corrosion coating 9, an inlet valve 10, an outlet valve 11, a polytetrafluoroethylene light-transmitting film 12, a light shield 13, a light shielding plate 15, a sealing gasket 16 and a fixed collar 17.

[0038] The air chamber cylinder 7 is an aluminum alloy cylinder with a length of 100 cm and a diameter of 12 cm. An internal anti-corrosion coating 9 is provided on the inner wall of the air chamber cylinder 7. Holes are opened on the circumferential surface 10 cm away from both ends of the air chamber cylinder 7 for installing the inlet valve 10 and the outlet valve 11. The connection between the inlet valve 10 and the outlet valve 11 and the air chamber cylinder 7 must be absolutely sealed. Therefore, the inlet valve 10 and the outlet valve 11 are sealed and connected to the air chamber cylinder 7 with sealing gaskets 16.

[0039] A heat insulation protective layer 8 is arranged outside the air chamber cylinder 7 .

[0040] The inlet valve 10 and the outlet valve 11 are both needle valves. Needle valves are valves that can be precisely adjusted and are widely used. For example, the cutting distance for flame cutting and the knob for adjusting the flame temperature are needle valves. Instrument needle valves are important components in instrument measurement pipeline systems. They mainly include stop valves and ball valves. Their function is to open or cut off pipeline passages. The valve core of the needle valve is a very sharp cone that is inserted into the valve seat like a needle, hence the name.

[0041] The needle valve can withstand greater pressure than other types of valves and has good sealing performance, so it is generally used to seal gas or liquid media with smaller flow and higher pressure. Therefore, the inlet valve 10 and the outlet valve 11 of the present application both use needle valves. General needle valves are made into threaded connections. Applicable nominal pressure: PN2.5, PN4, PN6.4, PN16 and PN32Mpa; nominal diameter: DN5~DN25 Applicable media: oil, water, gas and other non-corrosive or corrosive media.

[0042] Both ends of the air chamber cylinder 7 are sealed with polytetrafluoroethylene light-transmitting films 12, and the two polytetrafluoroethylene light-transmitting films 12 are both covered with light-shielding covers 13 outside to prevent laser scattering.

[0043] The reason why polytetrafluoroethylene transparent film 12 is used instead of glass at both ends of the air chamber cylinder 7 is that the light transmittance of polytetrafluoroethylene transparent film 12 is determined by its special surface structure and chemical properties. The polytetrafluoroethylene transparent film 12 has very high transparency because its molecular structure contains a large number of fluorine atoms, which makes it have very low refractive index and absorption rate. This chemical structure makes the polytetrafluoroethylene transparent film 12 have excellent optical properties, can transmit most of the light, and produce the effect of high light transmittance, so the light transmittance is better than glass, and the calibration accuracy is higher.

[0044] The sunshade 13 is a hollow cylindrical cover, similar to the sunshade of a camera lens. The sunshade is made of aluminum alloy and is specially used to block strong sunlight.

[0045] When the handheld laser combustible gas detector needs to be calibrated, a light shielding plate 15 is disposed outside one of the light shields 13 .

[0046] When the fixed laser combustible gas detector needs to be calibrated, the shading plate 15 is not needed and can be removed.

[0047] The shading plate 15 is a completely opaque circular plate, and the diameter of the shading plate 15 is the same as the diameter of the air chamber cylinder 7. A groove is provided on the outside of one of the shading covers 13. When the shading plate 15 is needed, the shading plate 15 can be inserted into the groove. When the shading plate 15 is not needed, the shading plate 15 is taken out of the groove.

[0048] There can be three grooves, which are located at the bottom and both sides of the sunshade 13 respectively. The groove at the bottom is set upward, and the grooves on both sides are set opposite to each other. The sunshade 15 is inserted between these three grooves to ensure its normal use.

[0049] A copper fixing ring 17 is respectively arranged on the circumference of the air chamber cylinder 7 near both ends, which is used for sliding the standard air chamber 18 during multi-point detection.

[0050] The fixed laser combustible gas detector includes a laser transmitting end and a receiving end. When calibrating the fixed laser combustible gas detector, if you want to detect the gas concentration at multiple points between the transmitting end and the receiving end, hang the standard gas chamber 18 on the track or copper wire between the receiving and transmitting ends, and record the detection results while moving the standard gas chamber 18.

[0051] If the standard air chamber 18 does not need to be moved or is moved less frequently, a bracket can be installed at the bottom of the standard air chamber 18, such as Figure 2 As shown, the bracket includes a support rod 4 and a tripod bracket 2.

[0052] External threads are provided at the top and near the bottom of the support rod 4, and a fixed base 1 is provided at the axial center position of the circumference of the air chamber cylinder 7. The fixed base 1 is provided with internal threads, and the standard air chamber 18 is fixed to the top of the support rod 4 through threaded connection.

[0053] A fixed threaded sleeve 14 is provided on the top of the triangular bracket 2. The fixed threaded sleeve 14 is rotatably connected to the three legs of the triangular bracket 2. The fixed threaded sleeve 14 is nested at the bottom position of the support rod 4 and is threadedly connected to the corresponding external thread.

[0054] The bottoms of the three legs are all provided with anti-skid fixing rings 5, which have an anti-skid effect and improve the overall stability.

[0055] The support rod 4 is a telescopic rod, including a thick rod, a thin rod and a rotating lock 3. The thick rod is hollow, and the bottom of the thin rod extends into the thick rod and is slidably connected to the thick rod. The thin rod is located at the top and the thick rod is located at the bottom. The top of the thin rod is provided with an external thread for connecting with the fixed base 1, and the top and near the bottom of the thick rod are provided with external threads. The external thread near the bottom is used to connect with the tripod bracket 2.

[0056] The external thread at the top of the thick rod is threadedly connected to one end of the rotating lock buckle 3, and the other end of the rotating lock buckle 3 is sleeved on the thin rod. The thick rod and the thin rod are fixed by the rotating lock buckle 3, and the fixing principle is the same as the fixing principle of the telescopic mop rod.

[0057] The standard air chamber 18 can be stably placed in the air through the support rod 4 and the tripod bracket 2, and the height can be adjusted through the telescopic function of the support rod 4, which is suitable for different height conditions and convenient for calibration at different heights.

[0058] During on-site operation, the standard gas chamber 18 filled with standard gas can be placed on a fixed bracket to calibrate the handheld laser combustible gas detection device, or it can be hung on a track or copper wire to perform multi-point testing of a fixed laser combustible gas detector. It is simple to operate and easy to use.

[0059] The process of calibrating the laser combustible gas detector using the above laser combustible gas detector calibration device is as follows:

[0060] The combustible gas standard substance is filled into the standard gas chamber 18. Before filling, the air in the original standard gas chamber 18 must be replaced as cleanly as possible to prevent affecting the concentration of the filled gas. The combustible gas standard substance with a known corresponding concentration is filled into the corresponding marked standard gas chamber 18. Generally, the gas with a concentration of 10%, 40% and 60% of the full scale of the laser combustible gas detector is filled. The expanded uncertainty of the gas standard substance is not more than 2% (k=2).

[0061] The required gas is introduced through the inlet valve 10 and the outlet valve 11 to replace the original gas.

[0062] Generally, gas standard substances of the same type as the gas measured by the laser combustible gas detector are used. If the laser combustible gas detector does not indicate the type of gas measured, isobutane or propane gas standard substances can be used.

[0063] Measurement and indication error: After the laser combustible gas detector is powered on and preheated to stabilize at the installation position, clean air is loaded into the standard gas chamber 18, and the gas standard material of about 60% of the full scale of the laser combustible gas detector is filled into the standard gas chamber 18. Before use, the original air must be replaced as cleanly as possible, and the standard gas chamber 18 is placed in the detection beam emitted by the laser combustible gas detector. The zero point and indication of the laser combustible gas detector are adjusted respectively. Then, the standard gas chamber 18 filled with gas standard materials of about 10%, 40%, and 60% of the full scale are placed respectively, and the stable indication of the laser combustible gas detector is recorded. Repeat the measurement three times for each point. Calculate the indication error of each point, and adjust the laser combustible gas detector to an acceptable error range.

[0064] Measure the response time: place the standard gas chamber 18 filled with clean air in the detection beam of the emitting end of the laser combustible gas detector. After adjusting the zero point of the laser combustible gas detector, place the standard gas chamber 18 filled with gas standard material at about 40% of the full scale of the laser combustible gas detector in the detection beam emitted by the laser combustible gas detector. Record the stable indication of the laser combustible gas detector. Remove the standard gas chamber 18 to allow the laser combustible gas detector to return to zero point. Then place the standard gas chamber 18 with the above 40% gas standard material and start the stopwatch at the same time. When the indication rises to 90% of the above stable indication, stop the stopwatch and record the time displayed by the stopwatch. Repeat the measurement three times according to the above operation method. The arithmetic mean of the three measurement results is the response time of the laser combustible gas detector. Determine whether the response time meets the requirements. The response time should not be greater than 10s.

[0065] Measuring light intensity attenuation: After the laser combustible gas detector is powered on and preheated to stabilize at the installation position, place the dimming film in the detection light path to attenuate the radiation flux of the detection beam by 50%. Under the condition that the radiation flux of the detection beam is attenuated by 50%, place the standard gas chamber 18 containing 40% of the full-scale gas standard material of the laser combustible gas detector in the detection beam emitted by the laser combustible gas detector, and the dimming film is located between the transmitting end of the laser combustible gas detector and the standard gas chamber 18. Observe whether the laser combustible gas detector can monitor normally. The laser combustible gas detector should be able to send out an alarm signal. Remove the dimming film. If the laser combustible gas detector can automatically or manually return to the normal monitoring state, it is considered that the light intensity performance of the laser combustible gas detector is good.

[0066] When using the standard gas chamber 18 for calibration, in order to ensure the stability of the laser combustible gas detector light beam, the standard gas chamber 18 must be fixed on the bracket, and the best channel for the light beam must be found by moving and lifting the bracket.

[0067] Fixed rings 17 are installed at both ends of the outer wall of the standard gas chamber 18. If you want to detect the gas concentration at multiple points between the transmitting end and the receiving end, or calibrate the measurement accuracy at different distances, hang the standard gas chamber 18 on the track or copper wire between the receiving and transmitting ends, move the standard gas chamber 18 while recording the test results, and detect the measurement accuracy at different distances.

[0068] The above process is applicable to both fixed laser combustible gas detectors and handheld laser combustible gas detectors.

[0069] When calibrating a fixed laser combustible gas detector, it is not necessary to install the shading plate 15 . Instead, the standard gas chamber 18 needs to be placed between the transmitting end and the receiving end of the fixed laser combustible gas detector, and it is ensured that the emitted detection beam can pass through both ends of the standard gas chamber 18 .

[0070] When calibrating the handheld laser combustible gas detector, it is necessary to install the shading plate 15 and place the standard gas chamber 18 on the detection beam path emitted by the handheld laser combustible gas detector to ensure that the emitted detection beam can pass through one end of the standard gas chamber 18 and be blocked by the shading plate 15 at the other end of the standard gas chamber 18 and will not continue to extend to the outside.

[0071] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0072] It should be understood that the above description is for illustration and not for limitation. Many embodiments and many applications beyond the examples provided will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of the present teachings should not be determined with reference to the above description, but rather with reference to the foregoing claims and the full scope of equivalents to which such claims are entitled. For the purpose of comprehensiveness, all articles and references, including disclosures of patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the foregoing claims is not intended to be a waiver of such subject matter, nor should it be considered that the applicant has not considered such subject matter to be part of the disclosed inventive subject matter.

Claims

1. A laser combustible gas detector calibration device, characterized in that: Including a standard air chamber (18); The standard air chamber (18) comprises an air chamber cylinder (7), an inlet valve (10), an outlet valve (11), a polytetrafluoroethylene light-transmitting film (12), a light shield (13) and a light shielding plate (15); Through holes are respectively opened on the circumference of the air chamber cylinder (7) near both ends, and the inlet valve (10) and the outlet valve (11) are respectively connected to the two through holes; both ends of the air chamber cylinder (7) are sealed with polytetrafluoroethylene light-transmitting films (12), and a light shielding plate (15) is detachably connected to the outside of one of the polytetrafluoroethylene light-transmitting films (12).

2. The laser combustible gas detector calibration device according to claim 1, characterized in that: A fixing ring (17) is respectively arranged on the circumferential surface of the air chamber cylinder (7) near both ends.

3. The laser combustible gas detector calibration device according to claim 1, characterized in that: The standard air chamber (18) is connected with a bracket.

4. The laser combustible gas detector calibration device according to claim 3, characterized in that: A fixed base (1) is arranged at the axial center position of the peripheral surface of the air chamber cylinder (7), and an internal thread is arranged on the fixed base (1); The bracket comprises a support rod (4) and a triangular bracket (2); the top and near the bottom of the support rod (4) are both provided with external threads; the fixed base (1) is connected to the external threads at the top of the support rod (4); the top of the triangular bracket (2) is provided with a fixed thread sleeve (14); the fixed thread sleeve (14) is nested at the bottom of the support rod (4) and is threadedly connected to the support rod (4) near the bottom.

5. The laser combustible gas detector calibration device according to claim 4, characterized in that: The support rod (4) is a telescopic rod.

6. The laser combustible gas detector calibration device according to claim 1, characterized in that: The two polytetrafluoroethylene light-transmitting films (12) are both covered with light shields (13) on the outside, and the light shielding plate (15) is detachably connected to the outside of one of the light shields (13).

7. A laser combustible gas detector calibration method based on the device according to any one of claims 1 to 6, characterized in that: Clean air is filled into a standard gas chamber (18), the standard gas chamber (18) is placed in the detection beam emitted by the laser combustible gas detector, and the zero point value of the laser combustible gas detector is adjusted; a gas standard substance of (60)% of the full scale of the laser combustible gas detector is filled into the standard gas chamber (18), the standard gas chamber (18) is placed in the detection beam emitted by the laser combustible gas detector, and the indication of the laser combustible gas detector is adjusted; then, gas standard substances of 10%, 40% and 60% of the full scale of the laser combustible gas detector are respectively filled into the standard gas chamber (18), each concentration is measured multiple times, the stable indication of the laser combustible gas detector is recorded, the indication error of each concentration is calculated, and it is judged whether the error meets the requirements.

8. The laser combustible gas detector calibration method according to claim 7, characterized in that: A standard gas chamber (18) filled with clean air is placed in the detection beam of the laser combustible gas detector. After adjusting the zero point of the laser combustible gas detector, a standard gas chamber (18) filled with a certain concentration of combustible gas is placed in the detection beam emitted by the laser combustible gas detector. The stable indication of the laser combustible gas detector is recorded. The standard gas chamber (18) is removed to allow the laser combustible gas detector to return to the zero point. The standard gas chamber (18) is then placed again. A stopwatch is started at the same time. When the indication rises to 90% of the above stable indication, the stopwatch is stopped and the time displayed by the stopwatch is recorded. The above operation method is repeated for multiple measurements. The arithmetic mean of the multiple measurement results is the response time of the laser combustible gas detector. Whether the response time meets the requirements is determined.

9. The laser combustible gas detector calibration method according to claim 7, characterized in that: A standard gas chamber (18) filled with a certain concentration of combustible gas and a dimming film are placed in the detection beam emitted by the laser combustible gas detector, with the dimming film located between the emission end of the laser combustible gas detector and the standard gas chamber (18). It is observed whether the laser combustible gas detector can monitor normally. If the dimming film is removed and the laser combustible gas detector can automatically or manually return to a normal monitoring state, it is considered that the light intensity performance of the laser combustible gas detector is good.

10. The laser combustible gas detector calibration method according to claim 7, characterized in that: When calibrating a fixed laser combustible gas detector, if it is necessary to detect the gas concentration at multiple points between the transmitting end and the receiving end, the standard gas chamber (18) is suspended on a track or copper wire between the receiving end and the transmitting end through a fixed collar (17), and the standard gas chamber (18) is moved to detect the measurement accuracy at different distances while recording the detection results.

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