A mobile intelligent gas detector

Abstract

This invention discloses a mobile intelligent gas detector, relating to the field of gas detection technology. It includes a housing and a pump, controller, and power supply disposed within the housing. It also includes multiple gas detection modules disposed outside the housing. Each gas detection module includes: a detection shell with a cylindrical cavity inside, divided into a detection chamber and a venting chamber; a rotating shaft rotatably mounted on the central axis of the cylindrical cavity; and a semi-cylindrical rotor fixed to the rotating shaft, with a circumferential angle greater than 180°. The rotor rotates into either the detection chamber or the venting chamber. The venting chamber has a fixed wall, while the detection chamber wall is formed by multiple arc-shaped plates sequentially spliced ​​circumferentially. The inner surfaces of all arc-shaped plates are covered with an integral elastic sealing sleeve, and elastic sealing lips connect the arc-shaped plates at both ends to the venting chamber wall. This invention truly enables one-button on-site intelligent detection.

Description

Technical Field

[0001] This invention relates to the field of gas detection technology, specifically a mobile intelligent gas detector. Background Technology

[0002] Mobile intelligent gas detectors are widely used in industrial inspections, emergency response, and environmental monitoring. Operators can use them handheld or vehicle-mounted / airborne methods for rapid on-site multi-gas detection. However, current multi-gas detectors suffer from the following prominent problems when facing complex detection tasks: First, cross-contamination is difficult to eliminate. Existing equipment mainly relies on continuous purging with air pumps to reduce cross-interference between sensors. However, the airflow follows the path of least resistance, and residual gas molecules in "dead zones" such as sensor surfaces, pipe joints, and cavity corners can only be carried away by slow diffusion. After a high-concentration detection, residual gas may continue to be released for several hours, seriously interfering with subsequent low-concentration measurements. As a "mobile" device, it needs to perform different tasks continuously in different locations, making the false alarms and accuracy reduction caused by cross-contamination even more prominent.

[0003] Secondly, the detection accuracy is limited by flow noise; when the pump-suction detector is working, the pulsation of the air pump and pressure fluctuations continuously act on the sensor, introducing measurement noise that cannot be ignored, which limits the lower limit and repeatability of trace gas detection.

[0004] Third, sensors lack effective protection in mobile scenarios; mobile devices frequently experience vibration, temperature and humidity changes when not in operation, but the sensors of existing instruments are usually connected to the environment through a normally open air port. Long-term exposure to trace pollutants can easily lead to irreversible poisoning, resulting in decreased sensitivity, requiring frequent calibration and replacement, which increases the burden of on-site maintenance.

[0005] Therefore, it is necessary to provide a mobile intelligent gas detector to solve the problems mentioned in the background art. Summary of the Invention

[0006] To achieve the above objectives, the present invention provides the following technical solution: a mobile intelligent gas detector, comprising a housing and a pump, controller, and power supply disposed within the housing, and further comprising multiple gas detection modules disposed outside the housing. Each gas detection module comprises: a detection shell having a cylindrical cavity inside, the cylindrical cavity being divided into a detection cavity and a venting cavity; a rotating shaft rotatably mounted on the central axis of the cylindrical cavity; and a semi-cylindrical rotor fixed to the rotating shaft, with a circumferential angle greater than 180°, the rotor rotating into either the detection cavity or the venting cavity; wherein the venting cavity has a fixed cavity wall, and the cavity wall of the detection cavity is formed by multiple arc-shaped plates sequentially spliced ​​circumferentially, the inner surfaces of all the arc-shaped plates being covered with an integral elastic sealing sleeve, and elastic sealing lips connecting the arc-shaped plates at both ends to the cavity wall of the venting cavity.

[0007] Preferably, a plurality of hydraulic telescopic rods are provided between the outer side of the arc-shaped plate and the inner side of the cylindrical cavity, and the telescopic direction of the hydraulic telescopic rods is radially extended and retracted along the arc-shaped plate and the cylindrical cavity.

[0008] Preferably, each of the two circumferential sides of the arc-shaped plate is provided with a sliding groove. The groove depth direction is parallel to the tangent direction of the splicing surface at the splicing surface of two adjacent arc-shaped plates. Two adjacent arc-shaped plates are slidably connected by a connecting plate. The two ends of the connecting plate are slidably embedded in the corresponding sliding grooves on the two adjacent arc-shaped plates, forming a linear sliding pair that guides multiple arc-shaped plates to expand or contract synchronously in the radial direction.

[0009] Preferably, the inner diameter of the venting cavity is larger than the outer diameter of the rotor; the elastic sealing sleeve is uniformly pressed against the outer circumferential surface of the rotor to form a static seal when the arc plate contracts, and disengages from the outer circumferential surface of the rotor to form a gap for the rotor to rotate without friction when the arc plate expands.

[0010] Preferably, a gas sensor is installed at one axial end of the detection cavity, and multiple air inlets are opened at the other axial end of the detection cavity away from the gas sensor. An active opening and closing door independently controlled by the controller is provided at each air inlet. Replacement ports are opened at both axial ends of the venting cavity. The venting cavity is connected to the housing, and the suction inlet of the air pump is located in the middle of the arc-shaped cavity wall of the venting cavity.

[0011] Preferably, the rotor has a gas channel, the outlet of the gas channel is located on the arc-shaped circumferential surface of the rotor and aligned with the axial position of the suction inlet of the air pump; the inlet of the gas channel is located on the vertical wall of the rotor and the axial position of the inlet of the gas channel is located at the end close to the gas sensor.

[0012] Preferably, the replacement port includes a first air port located in the middle of the venting cavity and a contoured air port located at the edge of the venting cavity.

[0013] Preferably, the gas detection module has two working positions: a detection position and a venting position. In the detection position, the rotor rotates into the venting chamber, the gas channel connects the detection chamber to the vacuum pump, and the displacement port is blocked by the rotor. In the venting position, the rotor rotates into the detection chamber, the air inlet is blocked by the rotor, and the displacement port is opened.

[0014] Preferably, the controller is configured to perform the following detection procedure: control the arc plate to expand, causing the rotor to rotate without friction to the detection station; control the arc plate to contract, forming a static seal; open the active opening and closing door and start the vacuum pump to replace the gas to be tested and then close it; read the measurement data of the gas sensor in an absolutely sealed state; after the detection is completed, control the arc plate to expand, causing the rotor to rotate without friction to the venting station, then contract to form a seal and start the vacuum pump for venting and cleaning.

[0015] Compared with existing technologies, this invention provides a mobile intelligent gas detector with the following advantages: This invention actively pushes the waste gas in the detection chamber into the exhaust chamber and forces it out through the physical squeezing action of the rotor, replacing passive purging and dilution with mechanical expulsion, thereby eliminating cross-contamination sources and ensuring the data independence and reliability of continuous multi-point detection by the mobile device; simultaneously, through the contraction of the arc-shaped plate and the elastic sealing sleeve, the detection chamber is transformed into a static, sealed space with fixed volume, no airflow, and no pressure fluctuations, thereby improving the detection accuracy of the gas sensor; and through the retractable arc-shaped plate and the fixed gap between the exhaust chamber and the rotor (with an inner diameter larger than the rotor)... The design decouples the rotor's rotational motion from the sealing action of the arc-shaped plates in time. During rotation, the cavity wall expands to form a gap, preventing the rotor from contacting the cavity wall and avoiding wear. During sealing, the cavity wall contracts, causing the elastic sealing sleeve to uniformly press the rotor over a large area to form a static seal. This solves the contradiction between friction and wear and cleanliness in traditional dynamic seals, achieving a balance between long life, high cleanliness, and low power consumption. The arc-shaped plates are connected by sliding grooves and independent connecting plates to form a linear sliding pair, enabling all arc-shaped plates to move radially synchronously and at equal intervals. The motion has high repeatability and determinism, which can significantly reduce the number of drive sources and effectively save costs. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the gas detection module in this invention; Figure 3This is a schematic diagram of the internal structure of the detection shell in this invention. Figure 1 ; Figure 4 This is a schematic diagram of the internal structure of the detection shell in this invention. Figure 2 ; Figure 5 This is a schematic diagram of the detection cavity in this invention; Figure 6 This is a schematic diagram of the venting cavity in this invention; Figure 7 This is a schematic diagram of the arc-shaped plate in this invention; Figure 8 This is a schematic diagram of the expansion and contraction state changes of the arc-shaped plate in this invention; Figure 9 This is a schematic diagram of the rotor structure in this invention; In the diagram: 1. Shell; 2. Detection shell; 21. Cylindrical cavity; 22. Detection chamber; 221. Air inlet; 222. Active opening and closing door; 23. Exhaust cavity; 231. Replacement port; 231a. First air inlet; 231b. Contour air inlet; 24. Arc plate; 241. Slide groove; 242. Connecting plate; 25. Elastic sealing sleeve; 26. Hydraulic telescopic rod; 3. Rotating shaft; 4. Rotor; 41. Gas passage; 41a. Outlet; 41b. Inlet; M. Arc plate splicing surface; N. Tangent of splicing surface. Detailed Implementation

[0017] Please see Figures 1-9 In this embodiment of the invention, a mobile intelligent gas detector is provided. The detector includes a housing 1 that can be held by hand or installed on a mobile mechanism (mobile vehicle or drone). The housing 1 integrates a miniature air pump, a controller, and a rechargeable lithium battery power supply. Multiple independent gas detection modules are connected in parallel to the outside of the housing 1 through standard gas circuit interfaces and electrical interfaces. Each gas detection module has an independent detection shell 2. The gas detection modules can work and be replaced independently.

[0018] In this embodiment, the gas detection module includes a detection housing 2, and a cylindrical cavity 21 is provided inside the detection housing 2. The cylindrical cavity 21 is divided into two functional areas, namely a detection cavity 22 and an exhaust cavity 23. The exhaust cavity 23 has a fixed semi-circular arc cavity wall, which is integrally formed with the detection housing 2. The cavity wall of the detection cavity 22 is formed by splicing multiple arc plates 24 in a circumferential direction. The inner surfaces of the multiple arc plates 24 are covered by an integral elastic sealing sleeve 25, which is integrally vulcanized from perfluoroether rubber (FFKM) and its inner surface is coated with diamond-like carbon (DLC) coating.

[0019] Furthermore, an elastic sealing lip is connected between the two arc-shaped plates 24 at both ends and the fixed cavity wall of the venting cavity 23. The elastic sealing lip is also made of FFKM material. When the arc-shaped plate 24 contracts, the elastic sealing lip is compressed under radial pressure, so that the walls of the detection cavity 22 and the venting cavity 23 form a continuous, unbroken, complete cylindrical wall.

[0020] In this embodiment, each of the arc-shaped plates 24 has a groove 241 on each of its two circumferential sides; the groove depth direction of the groove 241 is parallel to the tangent (N) of the splicing surface at the splicing surface (M) of two adjacent arc-shaped plates, and there is a pair of grooves 241 at each splicing surface (M); two adjacent arc-shaped plates 24 are slidably connected by an independent rectangular connecting plate 242 to form a linear sliding pair; when one of the arc-shaped plates 24 is subjected to radial driving force, all the arc-shaped plates 24 synchronously and equidistantly expand or contract radially through the rigid transmission of multiple connecting plates 242.

[0021] Furthermore, a plurality of miniature hydraulic telescopic rods 26 are evenly arranged axially between the outer side of the arc plate 24 and the inner side of the cylindrical cavity 21. The cylinder of the hydraulic telescopic rod 26 is fixed on the detection housing 2, and the piston rod end is connected to the outer side of the arc plate 24. The telescopic direction is radial along the cylindrical cavity 21.

[0022] It should be noted that since multiple arc-shaped plates 24 are connected by connecting plates 242 to form a synchronously retractable whole, during driving, hydraulic pressure can be supplied to all hydraulic telescopic rods 26 simultaneously to achieve synchronous driving, thereby obtaining the highest rigidity and synchronization accuracy. As a cost-saving alternative, active hydraulic pressure can also be supplied to the hydraulic telescopic rods 26 on only one arc-shaped plate 24, and the remaining arc-shaped plates 24 can be driven to move synchronously through the rigid transmission of the connecting plates 242. The remaining hydraulic telescopic rods 26 follow the action as auxiliary guides, thereby significantly reducing the number of hydraulic circuits.

[0023] In this embodiment, the rotating shaft 3 is rotatably mounted on the central axis of the cylindrical cavity 21 and is driven by a micro stepper motor through a planetary reducer. A semi-cylindrical rotor 4 is fixedly mounted on the rotating shaft 3. The circumferential angle of the rotor 4 is 195° (greater than 180°), and the outer circumferential surface is coated with DLC coating.

[0024] Furthermore, the inner diameter of the venting cavity 23 is larger than the outer diameter of the rotor 4, ensuring that the rotor 4 remains in a non-contact state with the fixed cavity wall of the venting cavity 23 during rotation.

[0025] When the hydraulic telescopic rod 26 pushes the arc plate 24 to retract radially, the elastic sealing sleeve 25 is evenly pressed onto the outer circumferential surface of the rotor 4 to form a static seal; at the same time, the end face flange structure of the elastic sealing sleeve 25 is pressed onto the front and rear end covers of the cylindrical cavity 21 to achieve axial sealing; the elastic sealing lip is compressed and deformed under radial pressure to seal the gap between the end of the arc plate 24 and the cavity wall of the venting cavity 23.

[0026] When the hydraulic telescopic rod 26 pulls the arc plate 24 to expand radially, the elastic sealing sleeve 25 disengages from the outer circumferential surface of the rotor 4, and the rotor 4 can rotate freely without friction.

[0027] In this embodiment, a gas sensor is installed at one axial end (rear end) of the detection cavity 22, with the sensitive surface of the gas sensor facing the inside of the detection cavity 22; multiple air inlets 221 are provided on the end cap at the other end (front end) of the detection cavity 22 away from the gas sensor, and each air inlet 221 is provided with an active opening and closing door 222. The door body of the active opening and closing door 222 is a miniature sliding plate structure, driven by a miniature electromagnet. The sliding plate moves in a plane parallel to the inner wall of the end cap to realize the opening and closing of the air inlet.

[0028] Furthermore, each of the two end caps at both ends of the axial direction of the venting cavity 23 is provided with a replacement port 231, including a first air port 231a located in the middle of the venting cavity 23 and a contoured air port 231b located at the edge of the venting cavity 23, the contour of which matches the outer periphery of the rotor 4, in order to increase the flow area and at the same time eliminate the dead corners of the air path in the venting cavity 23, ensuring that the gas in the venting cavity 23 can be completely replaced. The suction inlet of the air pump is located in the middle of the arc-shaped cavity wall of the venting cavity 23 and is connected to the pump body through an air passage pipe.

[0029] Meanwhile, a gas channel 41 is provided inside the rotor 4; the outlet 41a of the gas channel 41 is opened on the arc-shaped circumferential surface of the rotor 4, and its axial position is precisely aligned with the suction inlet of the air pump; the inlet 41b of the gas channel 41 is opened on the vertical wall of the rotor 4, and the axial position of the inlet is biased towards the end closer to the gas sensor; the inner wall of the gas channel 41 is also electrolytically polished, and the cross-section is streamlined to reduce gas residue.

[0030] It should be noted that removable filters can also be installed at the replacement port 231 and the air inlet 221 to prevent dust from entering the detection housing 2. At the same time, for some special gas detection work, other components of different components may affect the gas detection sensor. Therefore, it is necessary to adsorb and remove the gas components that may affect the detection before detection. Thus, an adsorption module can be detachably installed at the air inlet 221 (the specific adsorption mechanism can be freely selected according to the detection needs, which is existing technology and will not be described in detail here).

[0031] The controller executes the following detection procedure to complete a complete gas detection cycle: T1, expansion preparation; the controller instructs the hydraulic system to supply oil, and multiple hydraulic telescopic rods 26 simultaneously pull multiple arc plates 24 outward; under the guidance of the linear sliding pair formed by the connecting plate 242 and the slide groove 241, multiple arc plates 24 move radially outward simultaneously, and the elastic sealing sleeve 25 completely separates from the outer circumference of the rotor 4.

[0032] T2. Rotate to the detection station; the controller drives the stepper motor to rotate the shaft 3, and the rotor 4 rotates clockwise in a non-contact, non-friction state, and enters the venting cavity 23; at this time, the vertical wall of the rotor 4 faces the detection cavity 22, the outlet 41a of the gas channel 41 is aligned with the suction inlet of the air pump, and the inlet 41b of the gas channel 41 faces the gas sensor side; at the same time, the outer circumference of the rotor 4 completely covers and blocks the replacement ports 231 at both ends of the venting cavity 23.

[0033] T3, contraction seal; the controller instructs the hydraulic system to switch directions, and the hydraulic telescopic rod 26 pushes the arc plate 24 to contract radially inward; the elastic sealing sleeve 25 is evenly pressed on the outer circumferential surface of the rotor 4; the elastic sealing lip is compressed and deformed under the contraction pressure, filling the tiny gap between the end of the arc plate 24 and the cavity wall of the venting cavity 23, and the detection cavity 22 and the wall of the venting cavity 23 form a complete and continuous cylindrical wall.

[0034] T4. Gas replacement; The controller commands the active opening and closing valve 222 at the air inlet 221 to open and start the vacuum pump; The external gas to be tested (such as industrial waste gas containing hydrogen sulfide) is drawn into the detection chamber 22 from the air inlet 221, sweeps across the surface of the gas sensor from front to back in a laminar flow state, and then enters from the inlet 41b of the gas channel 41, and flows into the vacuum pump through the outlet 41a for discharge; After the vacuum pump works continuously at a fixed flow rate for a period of time (equivalent to replacing the volume of the detection chamber 22 several times), the controller commands the active opening and closing valve 222 and the vacuum pump to close; At this time, the detection chamber 22 is in an absolutely sealed state filled with the gas to be tested.

[0035] T5. Static detection: With the air pump and active opening / closing door 222 both closed and the cavity absolutely statically sealed, the controller reads the output signal of the gas sensor (such as an electrochemical hydrogen sulfide sensor) and calculates the precise concentration value of hydrogen sulfide gas.

[0036] T6. Emptying and cleaning; After the test is completed, the controller instructs the hydraulic telescopic rod 26 to pull the arc plate 24 to expand again, and the elastic sealing sleeve 25 disengages from the rotor; Drive the rotor 4 to rotate counterclockwise in a frictionless state and enter the test chamber 22; At this time, the outer circumference of the rotor 4 completely covers and blocks the air inlet 221 and its active opening and closing door 222, and the replacement ports 231 at both ends of the emptying chamber 23 open; Then the hydraulic telescopic rod 26 pushes the arc plate 24 to contract and form a seal again, and starts the air pump. Clean air is drawn in from the replacement port 231, flows through the emptying chamber 23 and is discharged from the outlet of the air pump, thoroughly cleaning the residual gas in the emptying chamber 23.

[0037] T7, Standby; All components are reset, and the gas detection module enters a low-power standby state, waiting for the next detection command.

[0038] In summary, this invention actively pushes the exhaust gas in the detection chamber 22 into the exhaust chamber 23 and forces it out through the physical squeezing action of the rotor 4. This deterministic mechanical expulsion replaces passive purging and dilution, thereby eliminating cross-contamination sources and ensuring the data independence and reliability of continuous multi-point detection by mobile equipment. Simultaneously, the contraction of the arc-shaped plate 24 in conjunction with the elastic sealing sleeve 25 transforms the detection chamber 22 into a static, sealed space with a fixed volume, no airflow, and no pressure fluctuations, resulting in higher detection accuracy for the gas sensor. Furthermore, the design of the retractable arc-shaped plate 24 and the fixed-gap exhaust chamber 23 with an inner diameter larger than that of the rotor 4 effectively controls the rotational motion of the rotor 4. The sealing action of the arc plate 24 is decoupled in time. When rotating, the cavity wall expands to form a gap, so that the rotor 4 does not contact the cavity wall and avoids wear. When sealing, the cavity wall contracts so that the elastic sealing sleeve 25 presses the rotor 4 evenly over a large area to form a static seal. This solves the contradiction between friction and wear and cleanliness in traditional dynamic sealing, and balances long life, high cleanliness and low power consumption. The arc plates 24 are connected by a linear sliding pair formed by the sliding groove 241 and the independent connecting plate 242, so that all the arc plates 24 can move radially synchronously and at equal distances. The movement has high repeatability and determinism, which can significantly reduce the number of drive sources and effectively save costs.

[0039] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A mobile intelligent gas detector, comprising a housing (1) and a pump, controller, and power supply disposed within the housing (1), and further comprising a plurality of gas detection modules disposed outside the housing (1), characterized in that, The gas detection module includes: The detection housing (2) has a cylindrical cavity (21) inside, which is divided into a detection cavity (22) and an venting cavity (23); The rotating shaft (3) is rotatably mounted on the central axis of the cylindrical cavity (21); A semi-cylindrical rotor (4) is fixed on the rotating shaft (3) and its circumferential angle is greater than 180°. The rotor (4) rotates into the detection chamber (22) or the venting chamber (23). The venting cavity (23) has a fixed cavity wall, and the cavity wall of the detection cavity (22) is formed by multiple arc-shaped plates (24) spliced ​​together in the circumferential direction. The inner side of all the arc-shaped plates (24) is covered with an integral elastic sealing sleeve (25), and the arc-shaped plates (24) at both ends are connected to the cavity wall of the venting cavity (23) with an elastic sealing lip.

2. A mobile intelligent gas detector according to claim 1, characterized in that, Multiple hydraulic telescopic rods (26) are provided between the outer side of the arc plate (24) and the inner side of the cylindrical cavity (21). The telescopic direction of the hydraulic telescopic rods (26) is radially extended and retracted along the arc plate (24) and the cylindrical cavity (21).

3. A mobile intelligent gas detector according to claim 1, characterized in that, The arc-shaped plate (24) has a groove (241) on each of its two circumferential sides. The groove depth of the groove (241) is parallel to the tangent (N) of the splicing surface at the splicing surface (M) of two adjacent arc-shaped plates. Two adjacent arc-shaped plates (24) are slidably connected by a connecting plate (242). The two ends of the connecting plate (242) are slidably embedded in the corresponding grooves (241) on the two adjacent arc-shaped plates (24), forming a linear sliding pair that guides the multiple arc-shaped plates (24) to expand or contract synchronously in the radial direction.

4. A mobile intelligent gas detector according to claim 1, characterized in that, The inner diameter of the venting cavity (23) is larger than the outer diameter of the rotor (4); The elastic sealing sleeve (25) is uniformly pressed against the outer circumferential surface of the rotor (4) to form a static seal when the arc plate (24) contracts. When the arc plate (24) expands, it separates from the outer circumferential surface of the rotor (4) and forms a gap for the rotor (4) to rotate without friction.

5. A mobile intelligent gas detector according to claim 1, characterized in that, A gas sensor is installed at one axial end of the detection chamber (22), and multiple air inlets (221) are opened at the other axial end of the detection chamber (22) away from the gas sensor. An active opening and closing door (222) independently controlled by the controller is provided at the air inlet (221). The venting cavity (23) has a replacement port (231) at both axial ends. The venting cavity (23) is connected to the housing (1), and the air intake of the air pump is located in the middle of the arc-shaped cavity wall of the venting cavity (23).

6. A mobile intelligent gas detector according to claim 5, characterized in that, A gas passage (41) is provided in the rotor (4), and the outlet (41a) of the gas passage (41) is located on the arc-shaped circumferential surface of the rotor (4) and is aligned with the axial position of the suction inlet of the air pump. The inlet (41b) of the gas channel (41) is located on the vertical wall of the rotor (4), and the axial position of the inlet (41b) of the gas channel (41) is located at one end close to the gas sensor.

7. A mobile intelligent gas detector according to claim 6, characterized in that, The replacement port (231) includes a first air port (231a) located in the middle of the venting cavity (23) and a contoured air port (231b) located at the edge of the venting cavity (23).

8. A mobile intelligent gas detector according to claim 6, characterized in that, The gas detection module has two working stations: a detection station and a venting station. During the testing station, the rotor (4) rotates into the venting chamber (23), the gas channel (41) connects the testing chamber (22) to the vacuum pump, and the replacement port (231) is blocked by the rotor (4); During the emptying station, the rotor (4) rotates into the detection chamber (22), the air inlet (221) is blocked by the rotor (4), and the replacement port (231) is opened.

9. A mobile intelligent gas detector according to claim 8, characterized in that, The controller is configured to execute the following detection procedure: control the arc plate (24) to expand, so that the rotor (4) rotates to the detection station without friction; The arc-shaped plate (24) is controlled to contract, forming a static seal; Open the active opening and closing door (222) and start the air pump to replace the gas to be tested and then close it; Read the measurement data of the gas sensor under absolutely sealed conditions; After the test is completed, the arc plate (24) is expanded so that the rotor (4) rotates without friction to the emptying position, and then shrinks to form a seal before starting the air pump to empty and clean.

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