Combustible gas testing device based on pyroelectric infrared detector

Abstract

The application relates to the technical field of gas detection devices, in particular to a combustible gas testing device based on a pyroelectric infrared detector, which comprises, from top to bottom, a test box, a gas chamber, a driver, a cleaner and a mounting plate. The combustible gas testing device based on the pyroelectric infrared detector converts linear displacement into the rotary motion of the mounting frame through a pair of adjustable moving parts, limits the deflection angle of the infrared light source and the pyroelectric infrared detector, and realizes the automatic switching of the detection device between the conventional mode and the long optical path mode.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gas detection devices, in particular to a combustible gas testing device based on a pyroelectric infrared detector. BACKGROUND

[0002] The combustible gas testing device based on a pyroelectric infrared detector is dedicated to combustible gas detection. Its core lies in the use of the characteristic that combustible gas has an absorption peak in a specific infrared waveband. A pyroelectric crystal such as lithium tantalate is built into the detector, which is sensitive to infrared radiation of a specific wavelength. When the combustible gas in the environment absorbs the energy emitted by the infrared light source, the intensity of the radiation received by the detector changes. This change is converted into an electrical signal by the pyroelectric crystal. The device has the advantages of non-contact measurement, good selectivity, strong anti-interference ability, long service life, and is suitable for real-time online monitoring and early warning in the fields of industrial safety and environmental monitoring.

[0003] A patent with the application number CN202020766025.3 discloses an NDIR gas detection module based on a pyroelectric infrared detector, which includes a shell and an optical cavity. The shell is fixed on a circuit board. A detection gas chamber is arranged in the shell. A gas window is formed in the shell and communicates with the detection gas chamber. The optical cavity is arranged in the detection gas chamber. A straight optical channel is arranged in the optical cavity. A gas hole is formed in the cavity wall of the optical cavity. An infrared light source and a pyroelectric infrared detector are arranged in the optical cavity along the axial direction of the optical channel.

[0004] However, the traditional combustible gas testing device has two structural and functional deficiencies. First, the optical path is fixed and single, which cannot balance high-concentration rapid detection and low-concentration accurate detection, resulting in insufficient sensitivity when monitoring trace gas leakage and a risk of false reporting. Second, there is a lack of automatic cleaning mechanism linked with detection. The gas path and the protective gas film are easily blocked by dust pollutants in the environment, which not only affects the gas diffusion efficiency and measurement accuracy, but also requires frequent manual cleaning and maintenance. The long-term stability and reliability of the device in complex industrial environments are significantly insufficient.

[0005] In view of this, we propose a combustible gas testing device based on a pyroelectric infrared detector. SUMMARY

[0006] The present application aims to provide a combustible gas testing device based on a pyroelectric infrared detector. By using a pair of adjustable moving parts, linear displacement is converted into rotational motion of the mounting bracket, and the deflection angle of the infrared light source and the pyroelectric infrared detector is limited. The automatic switching of the detection device between the conventional mode and the long-path mode is realized to solve the problems raised in the background art.

[0007] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0008] The combustible gas testing device based on pyroelectric infrared detector comprises a testing box, a gas chamber, a driver, a cleaner and a setting plate arranged in sequence from top to bottom.

[0009] The gas chamber comprises a cover plate, an infrared light source and a pyroelectric infrared detector arranged inside the cover plate, and a plurality of reflecting mirrors arranged on the inner wall of the cover plate.

[0010] The relative positions of the infrared light source and the pyroelectric infrared detector are adjusted, and the light of the infrared light source can be transmitted to the pyroelectric infrared detector through the plurality of reflecting mirrors.

[0011] The driver comprises a motor, a bidirectional screw rod driven by the motor, and a pair of moving parts, the moving parts comprising a sliding block, a rotating cylinder arranged on the top surface of the sliding block, a wire reel sleeved outside the rotating cylinder, and a connecting rope wound on the wire reel.

[0012] The motor drives the bidirectional screw rod to drive the moving parts to displace, the connecting rope pulls the wire reel to drive the rotating cylinder to rotate at a fixed distance, so as to adjust the angle of the infrared light source and the pyroelectric infrared detector.

[0013] The cleaner comprises an air cylinder, a pair of push plates arranged in the air cylinder, and a pair of air covers arranged on the outer walls of the air cylinder.

[0014] During the reciprocating movement of the push plates with the sliding block, external airflow is blown out through the air covers.

[0015] In the technical scheme of the present application, the testing box comprises a box body clamped and fixed on the top surface of the setting plate, the left and right outer walls of the box body are each provided with an internally and externally communicating clamping groove, the inside of the box body is provided with a longitudinally sectioned funnel-shaped air guide groove, and the upper and lower end slots of the air guide groove are respectively connected with the clamping groove and the inner wall of the box body.

[0016] In the technical scheme of the present application, the testing box further comprises a flow guide piece clamped on the top slot of the air guide groove, and a gas film clamped and fixed in the inside of the clamping groove.

[0017] The above arrangement ensures the overall structural strength through the cooperation of the box body and the setting plate, provides a stable mounting position for the gas film through the clamping groove, and accelerates the gas flow and uniformly guides it through the funnel-shaped air guide groove and the flow guide piece, and effectively blocks external dust through the gas film, thereby jointly constructing an efficient and stable gas pretreatment channel.

[0018] In the technical scheme of the present application, the gas chamber further comprises a bottom plate clamped on the bottom surface of the cover plate, and a pair of mounting racks for fixing the infrared light source and the pyroelectric infrared detector, and a pair of limiting grooves are arranged on the top surface of the bottom plate.

[0019] The outer wall of the cover plate is provided with a plurality of regularly distributed air holes, the top of the cover plate is semicircular, the mounting frame of the infrared light source and the pyroelectric infrared detector is clamped and fixed in the mounting frame, and the reflecting mirror is adhesively fixed in the groove of the inner wall of the cover plate.

[0020] The above arrangement realizes flexible switching of the optical detection path between the normal mode and the long optical path mode through the adjustable-angle mounting frame and the reflecting mirror, significantly improves the detection sensitivity of the instrument to trace gases, and suppresses the interference of environmental temperature fluctuation on the measurement through the air hole design on the cover plate.

[0021] In the technical scheme of the present application, the driver further comprises a support frame fixedly connected to the top surface of the placement plate by screws, a pair of upper and lower through-slots are formed in the top surface of the support frame, a partition plate is hot melt connected to the center of the inner wall of the support frame, and the bottom plate is clamped in the inner part of the support frame.

[0022] In the technical scheme of the present application, the motor is fixedly connected to the top surface of the placement plate by screws, the end of the bidirectional screw rod is coaxially connected with the output shaft of the motor, and the other end is rotationally connected to the inner wall of the support frame at the bottom of the support frame.

[0023] In the technical scheme of the present application, the longitudinal section of the sliding block is T-shaped and is slidingly connected to the inner part of the through-slot, the sliding block is threadedly connected to the outer side of the bidirectional screw rod, a limiting ring is hot melt connected to the top surface of the sliding block, and a plurality of arc-shaped grooves are formed in the inner part of the limiting ring.

[0024] In the technical scheme of the present application, the moving part further comprises a plug rod clamped to the top surface of the sliding block, a volute spring with the inner side end clamped to the outer wall of the plug rod, a rotating plate clamped to the outer wall of the rotating cylinder and with the outer wall protrusion rotationally connected to the inner part of the arc-shaped groove, the outer side end of the volute spring is clamped to the inner wall of the rotating cylinder, and the end of the connecting rope is adhesively connected to the outer wall of the partition plate.

[0025] The above arrangement accurately converts linear motion into limited rotary motion, thereby reliably driving the optical assembly to deflect by a predetermined angle, providing core power and precise control for adaptive variable optical path detection.

[0026] In the technical scheme of the present application, the air cylinder is clamped to the top surface of the placement plate, the push plate is slidingly arranged in the inner part of the air cylinder, a connecting rod is clamped between the bottom ends of the push plate and the sliding block, the air cover is clamped to the outer side of the opening in the inner part of the box body, and a one-way air valve is threadedly connected to the top surface of the air cylinder and the inner part of the air cover.

[0027] This arrangement converts the reciprocating motion of the driver into the piston action of the push plate in the air cylinder through the connecting rod, generates directional air flow, and performs reverse sweeping of the air film from inside to outside through the air cover, thereby realizing the automatic cleaning function in the detection process and effectively maintaining the air passage unobstructed.

[0028] Compared with the prior art, the present application has the following advantages:

[0029] 1. The combustible gas testing device based on pyroelectric infrared detector, by a pair of adjustable moving parts, converts linear displacement into rotating movement of the mounting frame, and limits the deflection angle of the infrared light source and the pyroelectric infrared detector, realizes automatic switching of the detection device between the conventional mode and the long optical path mode, makes the light in the gas chamber reflect through multiple mirrors to realize longer path reflection, and improves the detection sensitivity and accuracy of the system to trace gas, solves the problem of inaccurate detection of traditional sensors at low concentration, and ensures fast response at high concentration detection.

[0030] 2. The combustible gas testing device based on pyroelectric infrared detector, the cleaner is linked with the sliding block through the connecting rod, and the reciprocating linear motion of the moving part is directly converted into the piston motion of the push plate in the air cylinder, so that the air film can be automatically and regularly back blown after intermittent optical detection, thereby effectively removing dust and pollutants attached thereto, prolonging the maintenance period, reducing the artificial maintenance cost, and ensuring the long-term stability of the air passage and the detection result. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is a schematic diagram of the overall structure of the present application;

[0032] Figure 2 is a schematic diagram of the overall structure of the present application;

[0033] Figure 3 is a schematic diagram of the overall structure of the present application;

[0034] Figure 4 is a schematic diagram of the structure of the test box in the present application;

[0035] Figure 5 is a schematic diagram of the structure of the test box in the present application;

[0036] Figure 6 is a schematic diagram of the structure of the test box in the present application;

[0037] Figure 7 is a schematic diagram of the use state of the gas chamber in the present application;

[0038] Figure 8 is a schematic diagram of the use state of the gas chamber in the present application;

[0039] Figure 9 is a schematic diagram of the structure of the driver in the present application;

[0040] Figure 10 is a schematic diagram of the structure of the driver in the present application;

[0041] Figure 11 Structure split schematic diagram of mobile part in the application;

[0042] Figure 12 Structure split schematic diagram of cleaner in the application;

[0043] Legend:

[0044] 100, test box; 110, box body; 111, card slot; 112, air guide groove; 120, flow guide piece; 130, air film;

[0045] 200, air chamber; 210, bottom plate; 211, limiting groove; 220, cover plate; 221, air hole; 230, infrared light source; 240, pyroelectric infrared detector; 250, mounting frame; 260, reflector;

[0046] 300, driver; 310, support frame; 311, sliding groove; 320, partition; 330, motor; 340, bidirectional screw; 350, mobile part; 351, sliding block; 352, limiting ring; 3520, arc-shaped groove; 353, insertion rod; 354, spiral spring; 355, rotating drum; 356, rotating plate; 357, thread wheel; 358, connecting rope;

[0047] 400, cleaner; 410, air cylinder; 420, push plate; 430, connecting rod; 440, air cover; 450, one-way air valve;

[0048] 500, setting plate. DETAILED DESCRIPTION

[0049] The technical solutions in the application will be described clearly and completely below in combination with the drawings in the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0050] Please refer to Figures 1-4 The embodiments provide technical solutions as shown in the drawings:

[0051] The combustible gas testing device based on the pyroelectric infrared detector comprises, from top to bottom, a test box 100, an air chamber 200, a driver 300, a cleaner 400, and a setting plate 500.

[0052] Specifically, the test box 100 comprises a box body 110 fixed on the top surface of the placement plate 500, the left and right outer walls of the box body 110 are provided with an inner-outer through clamping groove 111, and the inner part of the box body 110 is provided with a longitudinally-section funnel-shaped air guide groove 112, the upper and lower ends of the air guide groove 112 are communicated with the clamping groove 111 and the inner wall of the box body 110 respectively.

[0053] Further, the test box 100 further comprises a flow guide piece 120 clamped on the top groove of the air guide groove 112 and an air film 130 clamped and fixed in the inner part of the clamping groove 111.

[0054] Further, the box body 110 cooperates with the placement plate 500 to ensure the strength of the overall structure, the clamping groove 111 is used for providing a placement interval for the air film 130, the air guide groove 112 is used for accelerating the gas flow rate, and the flow guide piece 120 is used for guiding the air flow, and the air film 130 is used for filtering the dust in the external environment, and the cooperation of the box body 110 and the placement plate 500 ensures the strength of the overall structure, the clamping groove 111 provides a stable installation position for the air film 130, the funnel-shaped air guide groove 112 and the flow guide piece 120 work together to accelerate the gas flow and uniformly guide, and the air film 130 effectively blocks the external dust, thereby jointly constructing an efficient and stable gas pretreatment channel.

[0055] Please refer to Figures 5-8 In the embodiment, the air chamber 200 comprises a cover plate 220, an infrared light source 230 and a pyroelectric infrared detector 240 arranged in the cover plate 220, and a plurality of reflecting mirrors 260 arranged on the inner wall of the cover plate 220, the relative positions of the infrared light source 230 and the pyroelectric infrared detector 240 are adjusted, and the light of the infrared light source 230 can be transmitted to the pyroelectric infrared detector 240 through the plurality of reflecting mirrors 260.

[0056] Specifically, the air chamber 200 further comprises a bottom plate 210 clamped on the bottom surface of the cover plate 220 and a pair of mounting frames 250 for fixing the infrared light source 230 and the pyroelectric infrared detector 240, and a pair of upper and lower through limiting grooves 211 are arranged on the top surface of the bottom plate 210.

[0057] Further, a plurality of regularly distributed air holes 221 are arranged on the outer wall of the cover plate 220, the top of the cover plate 220 is semicircular, the mounting frames 250 of the infrared light source 230 and the pyroelectric infrared detector 240 are clamped and fixed in the inner part of the mounting frame 250, and the reflecting mirrors 260 are adhesively fixed in the grooves on the inner wall of the cover plate 220.

[0058] Further, the limiting slot 211 on the bottom plate 210 is used to limit the moving range of the mounting frame 250, and the air hole 221 on the cover plate 220 is used to allow the gas to enter the inside of the cover plate 220 through the secondary free diffusion, so as to inhibit the influence of the external factors such as temperature, and after the relative position of the infrared light source 230 and the pyroelectric infrared detector 240 is adjusted, the light of the infrared light source 230 can be transmitted to the pyroelectric infrared detector 240 through the plurality of mirrors 260, so as to switch the detection between the normal mode and the long optical path mode, and the optical detection path can be flexibly switched between the normal mode and the long optical path mode through the mounting frame 250 with adjustable angle and the mirror 260, so as to significantly improve the detection sensitivity of the instrument to the trace gas, and the interference of the environmental temperature fluctuation on the measurement is inhibited through the design of the air hole 221 on the cover plate 220.

[0059] Please refer to Figures 9-11 In the embodiment, the driver 300 includes a motor 330, a bidirectional screw rod 340 driven by the motor 330, and a pair of moving parts 350, the moving part 350 includes a sliding block 351, a rotating cylinder 355 arranged on the top surface of the sliding block 351, a wire wheel 357 sleeved on the outside of the rotating cylinder 355, and a connecting rope 358 wound on the wire wheel 357, the motor 330 drives the bidirectional screw rod 340 to drive the moving part 350 to displace, the connecting rope 358 pulls the wire wheel 357 to drive the rotating cylinder 355 to rotate at a fixed distance, and the angle of the infrared light source 230 and the pyroelectric infrared detector 240 is adjusted.

[0060] Specifically, the driver 300 further includes a support frame 310 fixedly connected to the top surface of the placement plate 500 by screws, a pair of upper and lower through sliding grooves 311 are arranged on the top surface of the support frame 310, a partition plate 320 is hot melt connected to the center of the inner wall of the support frame 310, and the bottom plate 210 is clamped in the inside of the support frame 310.

[0061] Further, the motor 330 is fixedly connected to the top surface of the placement plate 500 by screws, the end of the bidirectional screw rod 340 is coaxially connected with the output shaft of the motor 330, and the other end is rotationally connected to the inner wall of the bracket at the bottom of the support frame 310.

[0062] Further, the longitudinal section of the sliding block 351 is T-shaped and is slidingly connected to the inside of the sliding groove 311, the sliding block 351 is threadedly connected to the outside of the bidirectional screw rod 340, a limiting ring 352 is hot melt connected to the top surface of the sliding block 351, and a plurality of arc-shaped grooves 3520 are arranged in the inside of the limiting ring 352.

[0063] Further, the moving part 350 further comprises a plug rod 353 clamped on the top surface of the slider 351, a volute spring 354 clamped on the outer wall of the plug rod 353 at the inner end, a rotating plate 356 clamped on the outer wall of the rotating cylinder 355 and rotatingly connected to the arc-shaped slot 3520 in the inner wall of the arc-shaped groove 352 by the protrusion on the outer wall, the outer end of the volute spring 354 is clamped on the inner wall of the rotating cylinder 355, and the end of the connecting rope 358 is adhered to the outer wall of the partition plate 320.

[0064] Further, the motor 330 in the driver 300 drives the bidirectional screw rod 340 to rotate, so that the sliders 351 in the pair of moving parts 350 move away from each other, and the connecting rope 358 pulls the wire wheel 357 to drive the rotating cylinder 355 to rotate, and the rotating plate 356 is limited in the rotating angle by the arc-shaped slot 3520 in the limiting ring 352, so that the rotating angle of the mounting frame 250 fixedly connected to the top of the rotating cylinder 355 can be determined, the accurate judgment of the micro-leakage is realized, and after the detection is completed, the motor 330 is started to drive the bidirectional screw rod 340 to reverse, so that the pair of moving parts 350 is reset, at this time, the elastic force of the volute spring 354 in the moving part 350 drives the rotating cylinder 355 to rotate, and the connecting rope 358 is re-wound outside the wire wheel 357, the linear motion is accurately converted into limited rotary motion, so that the optical assembly can be reliably driven to deflect by a predetermined angle, and the core power and accurate control for the self-adaptive variable path detection are provided.

[0065] Please refer to Figure 12 In the embodiment, the cleaner 400 comprises a cylinder 410, a pair of push plates 420 arranged in the cylinder 410, and a pair of air covers 440 arranged on the outer wall of the cylinder 410, the push plate 420 blows the external airflow through the air cover 440 during the reciprocating movement of the slider 351.

[0066] Specifically, the cylinder 410 is clamped on the top surface of the mounting plate 500, the push plate 420 slides in the inner part of the cylinder 410, the connecting rod 430 is clamped between the push plate 420 and the bottom end of the slider 351, the air cover 440 is clamped outside the opening in the inner part of the box body 110, and the one-way air valve 450 is threadedly connected to the inner part of the air cover 440 and the top surface of the cylinder 410.

[0067] Further, in the process of reciprocating movement of the moving part 350, the push plate 420 is driven to move synchronously in the air cylinder 410 by the connecting rod 430, and the external gas is filled into the air cylinder 410 through the one-way air valve 450 at the top of the air cylinder 410, and then the gas is sent into the air guide groove 112 of the box body 110 through the one-way air valve 450 in the air cover 440, so that the gas flow is discharged from inside to outside to clean the air film 130. This setting converts the reciprocating movement of the driver 300 into the piston action of the push plate 420 in the air cylinder 410 through the connecting rod 430, generates directional gas flow, and performs reverse blowing of the air film 130 from inside to outside through the air cover 440, realizes the automatic cleaning function in the detection process, and effectively maintains the smoothness of the gas circuit.

[0068] Finally, it should be noted that the infrared light source 230, the pyroelectric infrared detector 240 and the motor 330 involved in the present application are all general standard parts or components known to those skilled in the art, and their structure and principle are known to those skilled in the art through technical manuals or through conventional experimental methods. In the idle place of the device, the infrared light source 230, the pyroelectric infrared detector 240 and the motor 330 are connected with the external power supply through wires. The specific connection means should refer to the working principle in the present application, and the electrical connection between the electrical devices is completed according to the working order. The detailed connection means is a common technology in the art.

[0069] When the combustible gas test device based on the pyroelectric infrared detector of the present application is used in the conventional mode, the infrared light source 230 starts to work and emits two different wavelengths of infrared light after the system is powered on, and the pyroelectric infrared detector 240 starts to work at the same time. The system performs self-checking and preheating to a stable state.

[0070] When the combustible gas diffuses into the inside of the box body 110 through the air film 130 in the test box 100, and then diffuses into the inside of the cover plate 220 through the air hole 221 of the air chamber 200, the target gas molecules such as methane absorb infrared light of a specific wavelength of 3.3 μm, resulting in a decrease in the infrared signal intensity of the detection channel, while the infrared light of a wavelength of 3.95 μm in the reference channel is not absorbed, and its intensity remains unchanged.

[0071] The pyroelectric infrared detector 240 receives the infrared light attenuated by the two channels and generates weak electrical signals proportional to the light intensity, at this time, the weak electrical signals with differences between the two channels are sent to the analog amplification circuit for amplification and filtering processing to improve the signal quality and remove noise, the analog voltage signals after conditioning are sent to the microprocessor inside the device, and the signal strengths of the two channels are compared to measure the weakening degree of the channel signal relative to the reference channel signal, thereby reflecting the concentration of the target gas in the gas chamber 200, the higher the concentration, the more infrared light is absorbed, the weaker the signal of the measurement channel, the microprocessor converts the difference in light intensity into a specific gas concentration value according to the pre-stored calibration curve, and outputs in the form of an analog signal;

[0072] When the device detects trace gas, the internal processor determines that the signal is weak at this time, which may be close to the lower limit of detection, and drives the overall test device to enter the long light path mode, at this time, the motor 330 in the driver 300 drives the bidirectional screw rod 340 to rotate, and the slider 351 in the pair of moving parts 350 moves away from each other, thereby pulling the line wheel 357 with the connecting rope 358 to drive the rotating drum 355 to rotate;

[0073] The rotating plate 356 is limited in the rotation angle by the arc-shaped groove 3520 of the limiting ring 352 during the rotation of the rotating drum 355, so that the rotation angle of the mounting bracket 250 fixedly connected to the top of the rotating drum 355 can be determined, and the orientations of the infrared light source 230 and the pyroelectric infrared detector 240 are changed at the same time, so that the light of the infrared light source 230 can be transmitted to the pyroelectric infrared detector 240 through the plurality of reflecting mirrors 260, thereby improving the sensitivity and realizing accurate judgment of trace leakage, and after the detection is completed, the motor 330 is started to drive the bidirectional screw rod 340 to reverse, so that the pair of moving parts 350 is reset.

[0074] The foregoing description of specific exemplary embodiments of the application is intended for purposes of illustration and example only. These descriptions are not intended to limit the application in any way and it is clear that many modifications and variations to the illustrative embodiments will occur to those skilled in the art upon reading this description. It is intended that the scope of the application be defined by the following claims and their equivalents.

Claims

1. A combustible gas testing device based on a pyroelectric infrared detector, characterized in that: It includes, from top to bottom, a test box, an air chamber, a driver, a cleaner, and a mounting plate; The test box includes a box body that is snapped and fixed to the top surface of the mounting plate. The outer walls of both the left and right ends of the box body are provided with through slots, and the inside of the box body is provided with a funnel-shaped air guide groove. The air chamber includes a cover plate, an infrared light source and a pyroelectric infrared detector disposed inside the cover plate, and several reflectors disposed on the inner wall of the cover plate. After the relative positions of the infrared light source and the pyroelectric infrared detector are adjusted, the light from the infrared light source can be transmitted to the pyroelectric infrared detector through several reflectors. The driver includes a motor, a bidirectional lead screw driven by the motor, and a pair of moving parts. The moving parts include a slider, a rotating drum disposed on the top surface of the slider, a spool sleeved on the outside of the rotating drum, and a connecting rope wound around the spool. A limit ring is heat-fused to the top surface of the slider. The limit ring has several arc-shaped grooves inside. The motor drives the bidirectional lead screw to move the moving parts, and the connecting rope pulls the spool, causing the rotating drum to rotate at a fixed distance, thereby adjusting the angle of the infrared light source and the pyroelectric infrared detector. The moving part also includes a plug rod that is snapped onto the top surface of the slider, a spiral spring whose inner end is snapped onto the outer wall of the plug rod, and a rotating plate that is snapped onto the outer wall of the rotating cylinder and whose outer wall protrusion is rotatably connected to the inside of the arc groove. The cleaner includes an air cylinder, a pair of push plates disposed inside the air cylinder, and a pair of air covers disposed on the outer walls of both sides of the air cylinder. As the push plates move back and forth with the slider, they blow external airflow through the air covers.

2. The combustible gas testing device based on a pyroelectric infrared detector according to claim 1, characterized in that: The upper and lower ends of the air guide groove are connected to the card slot and the inner wall of the box, respectively.

3. The combustible gas testing device based on a pyroelectric infrared detector according to claim 2, characterized in that: The test box also includes a guide plate that snaps into the top opening of the air guide groove and an air film that snaps into and fixes inside the groove.

4. The combustible gas testing device based on a pyroelectric infrared detector according to claim 3, characterized in that: The air chamber also includes a base plate that is snapped onto the bottom surface of the cover plate and a pair of mounting brackets for fixing the infrared light source and the pyroelectric infrared detector. A pair of vertically penetrating limiting grooves are provided on the top surface of the base plate.

5. The combustible gas testing device based on a pyroelectric infrared detector according to claim 4, characterized in that: The outer wall of the cover plate has several regularly distributed air holes, the top of the cover plate is semi-circular, the mounting brackets of the infrared light source and the pyroelectric infrared detector are both snapped and fixed inside the mounting brackets, and the reflector is adhered and fixed to the groove on the inner wall of the cover plate.

6. The combustible gas testing device based on a pyroelectric infrared detector according to claim 5, characterized in that: The driver also includes a support frame that is fixedly connected to the top surface of the mounting plate by screws. A pair of vertically penetrating grooves are provided on the top surface of the support frame. A partition is heat-fused to the center of the inner wall of the support frame. The bottom plate is snapped into the inside of the support frame.

7. The combustible gas testing device based on a pyroelectric infrared detector according to claim 6, characterized in that: The motor is fixedly connected to the top surface of the mounting plate by screws. The end of the bidirectional lead screw is coaxially connected to the output shaft of the motor, and the other end is rotatably connected to the inner wall of the bottom bracket of the support frame.

8. The combustible gas testing device based on a pyroelectric infrared detector according to claim 7, characterized in that: The slider has a T-shaped longitudinal section and is slidably connected inside the groove, and the slider is threadedly connected to the outside of the bidirectional lead screw.

9. The combustible gas testing device based on a pyroelectric infrared detector according to claim 8, characterized in that: The outer end of the spiral spring is engaged with the inner wall of the rotating drum, and the end of the connecting rope is attached to the outer wall of the partition.

10. The combustible gas testing device based on a pyroelectric infrared detector according to claim 9, characterized in that: The air cylinder is snapped onto the top surface of the mounting plate, the push plate slides inside the air cylinder, a connecting rod is snapped between the bottom end of the push plate and the slider, the air cover is snapped onto the outside of the internal opening of the box, and a one-way air valve is threaded onto the top surface of the air cylinder and the inside of the air cover.

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