CN218727126U

CN218727126U - Harmful gas check out test set

Info

Publication number: CN218727126U
Application number: CN202222896244.5U
Authority: CN
Inventors: 凌锦程; 巫肇彬; 韦娜娜; 金玥; 罗思
Original assignee: Guangxi University of Science and Technology
Current assignee: Guangxi University of Science and Technology
Priority date: 2022-11-01
Filing date: 2022-11-01
Publication date: 2023-03-24
Anticipated expiration: 2032-11-01

Abstract

The utility model discloses a harmful gas check out test set, include: a mounting frame; the sliding groove is formed in the vertical section of the mounting frame, and a movable block which slides up and down is arranged in the sliding groove and used for detecting gases at different height positions; and a detection assembly disposed on the movable block for sucking and detecting harmful gas; the detection assembly comprises an installation sleeve, the installation sleeve is fixedly connected with the side wall where the movable block is located, the second installation frame is fixed inside the installation sleeve, and a first sensor and a second sensor are arranged on the second installation frame. The utility model discloses a power that belt drive assembly provided can be so that the fan body at determine module place moves to through the effect of first sensor and second sensor, cooperation screw drive assembly's effect is sucked and is detected gas in not co-altitude position promptly, thereby has further improved the accuracy nature that gaseous detected.

Description

Harmful gas check out test set

Technical Field

The utility model relates to a gaseous detection technology field specifically is a harmful gas check out test set.

Background

Along with the improvement of the standard of living, people pay more and more attention to indoor air quality, it can have many health problems to be in the room that harmful gas exists for a long time, for example acute carbon monoxide and carbon dioxide poisoning, cigarette smog, fuel burning, cooking oil smoke cause chronic obstructive pulmonary disease and air conditioner disease etc. current harmful gas check out test set position often sets up in a fixed position, but harmful gas is in indoor diffusion, its concentration differs, the numerical value that leads to check out test set to detect easily has the error, the accuracy is difficult to guarantee.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a harmful gas check out test set, the power that this equipment provided through belt drive assembly can be so that the fan body at determine module place moves to through the effect of first sensor and second sensor, cooperation screw drive assembly's effect is sucked and is detected gas in not co-altitude position promptly, has improved the accuracy nature that gaseous detected.

In order to achieve the above object, the utility model provides a following technical scheme: a harmful gas detection apparatus, comprising: a mounting frame; the sliding groove is formed in the vertical section of the mounting frame, and a movable block which slides up and down is arranged in the sliding groove and used for detecting gases at different height positions; and a detection assembly disposed on the movable block for sucking and detecting harmful gas; the detection assembly comprises an installation sleeve and a second installation frame, wherein the installation sleeve is fixedly connected with the side wall where the movable block is located, the second installation frame is fixed inside the installation sleeve, and a first sensor and a second sensor are arranged on the second installation frame; the air conditioner further comprises a first mounting frame fixed at the front end of the mounting sleeve, the middle of the first mounting frame is rotatably connected with a connecting shaft, and a fan body is fixed at one end, close to the second mounting frame, of the connecting shaft and used for sucking air; the screw rod adjusting component is arranged at the vertical section of the mounting rack and is used for driving the movable block to run; still including setting up belt drive assembly on the mounting bracket, work as when the movable block moves, belt drive assembly drives fan body work.

Preferably, the screw rod adjusting assembly comprises a mounting groove, the mounting groove is formed in the vertical section of the mounting frame, the screw rod adjusting assembly further comprises a screw bolt and a screw sleeve, the screw bolt is mounted in the mounting groove, the screw bolt rotates at the top of the mounting groove, the screw sleeve is connected to the outer wall of the screw bolt in a threaded mode, the screw sleeve is fixed to the movable block, and a meshing driving assembly is further arranged at the top of the vertical section of the mounting frame and used for controlling the screw bolt to rotate; still including setting up respectively the second contact switch at mounting groove bottom and top, when the swivel nut touching, second contact switch is used for the operation of regulation and control meshing drive assembly.

Preferably, the meshing driving assembly comprises a connecting column arranged at the top end of the stud, one end of the connecting column penetrates through a through hole formed in the mounting frame and is fixedly connected with the top of the stud, and a second transmission gear fixed at the other end of the connecting column; the two ends of the movable frame are respectively provided with a first motor and a first transmission gear fixed at the output end of the first motor, and the first transmission gear is meshed with the second transmission gear; the movable frame is arranged on the top of the vertical section of the mounting frame, and the movable frame is in contact with the first contact switches which are used for driving the first motor to run; and the groove is formed in the top of the vertical section of the mounting frame, the electric telescopic rod is arranged on the inner wall of the groove, and the telescopic end of the electric telescopic rod is fixed with the movable frame through the fixing piece and used for driving the movable frame to run.

Preferably, the belt transmission assembly comprises an installation plate fixed on the horizontal section of the installation frame and a second motor arranged on the front part of the installation plate, and a fourth transmission wheel is fixed at the output end of the second motor; the third driving wheel is rotatably connected to the front part of the movable block through a mounting shaft; the first driving wheel is fixed at one end, far away from the fan body, of the connecting shaft where the detection assembly is located; the second driving wheel is rotatably connected to the upper part of the vertical section of the mounting frame through a pin shaft; the transmission belt is in transmission connection among the fourth transmission wheel, the third transmission wheel, the first transmission wheel and the second transmission wheel.

Preferably, the side wall of the vertical section of the mounting rack is also provided with a control panel.

Preferably, the outer wall of the vertical section of the mounting frame is further provided with a warning indicator for warning that toxic gas exceeds the standard.

Preferably, a purifying box is fixed on the side wall of the threaded sleeve, which is far away from the movable block, the side wall of the purifying box is communicated with a conduit, and the conduit sequentially penetrates through holes respectively formed in the threaded sleeve and the movable block and extends into the mounting sleeve; the step part is arranged on the side wall of the purifying box far away from the guide pipe, and an air purifying layer is arranged on the step part and is used for purifying harmful gas; the side wall of the purifying box, which is far away from the guide pipe, is also provided with an elastic limiting assembly and a mounting ring arranged at the end part of the elastic limiting assembly, and the elastic limiting assembly is used for limiting and mounting an air purifying layer; also comprises an open slot arranged at the bottom of the purification box.

Preferably, the elastic limiting assembly comprises a mounting bar fixed on the side wall of the purifying box and a movable frame which passes through holes respectively formed in two ends of the mounting bar and can move in the through holes in a telescopic manner, and the end part of the movable frame is fixed with the mounting ring; and a plurality of springs are connected between the inner top of the mounting bar and the side wall of the movable frame.

Compared with the prior art, the beneficial effects of the utility model are as follows:

the utility model discloses an effect of first sensor and second sensor, can detect combustible gas and CO concentration in the gas, and effect through screw rod adjusting part, can make the movable block reciprocate, thereby make the first sensor and the second sensor at the detection component place of fixing on the movable block can detect gas at different heights, this process, utilize the power that belt drive assembly provided, can make the fan body at detection component place move, and effect through first sensor and second sensor, cooperation screw drive assembly's effect, aspirate and detect gas in different high positions promptly, thereby the accuracy nature of gas detection has further been improved.

Drawings

Fig. 1 is a schematic view of a first perspective three-dimensional structure of the present invention;

FIG. 2 is a perspective view of the second view angle of FIG. 1;

FIG. 3 is a perspective view of the third perspective view of FIG. 1;

FIG. 4 is a perspective view of the fourth perspective view of FIG. 1;

FIG. 5 is a schematic front view of the structure of FIG. 1;

FIG. 6 is an enlarged schematic view of the structure at A;

fig. 7 is a schematic view of an internal disassembled structure of the detection assembly.

In the figure: 1. a mounting frame; 2. a chute; 3. mounting grooves; 4. a stud; 5. a threaded sleeve; 6. a movable block; 7. a control panel; 8. a first drive pulley; 9. a groove; 10. a first contact switch; 11. a first motor; 12. a first drive tooth; 13. a second gear; 14. a second transmission wheel; 15. a pin shaft; 16. a drive belt; 17. a third transmission wheel; 18. a fourth transmission wheel; 19. a second motor; 20. mounting a plate; 21. a connecting shaft; 22. a first mounting frame; 23. a fan body; 24. a first sensor; 25. a second mounting frame; 26. a second sensor; 27. installing a sleeve; 28. a purification box; 29. an air purification layer; 30. a movable frame; 31. mounting a bar; 32. an open slot; 33. a spring; 34. a second contact switch; 35. a mounting ring; 36. an electric telescopic rod; 37. an alarm; 38. a movable frame.

Detailed Description

In the description of the present invention, it is to be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are merely for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. The following describes embodiments of the present invention in detail with reference to the accompanying drawings.

Referring to fig. 1 to 7, the present invention preferably provides a technical solution: a harmful gas detection apparatus, comprising: a mounting frame 1; the sliding chute 2 is arranged on the vertical section of the mounting frame 1, and a movable block 6 which slides up and down is arranged in the sliding chute 2 and is used for detecting the gas at different height positions; and a detection assembly provided on the movable block 6 for sucking and detecting harmful gas; the detection assembly comprises a mounting sleeve 27, a second mounting frame 25 fixed inside the mounting sleeve 27, and a first sensor 24 and a second sensor 26 arranged on the second mounting frame 25, wherein the mounting sleeve 27 is fixedly connected with the side wall where the movable block 6 is located; the air purifier also comprises a first mounting frame 22 fixed at the front end of the mounting sleeve 27, the middle part of the first mounting frame 22 is rotatably connected with a connecting shaft 21, and a fan body 23 is fixed at one end of the connecting shaft 21 close to the second mounting frame 25 and used for sucking air; and a screw adjusting component arranged at the vertical section of the mounting rack 1 and used for driving the movable block 6 to run; the fan further comprises a belt transmission component arranged on the mounting rack 1, and when the movable block 6 runs, the belt transmission component drives the fan body 23 to work.

In the present embodiment, the first sensor 24 and the second sensor 26 are preferably MQ2 and MQ7 sensors, respectively, the MQ2 and MQ7 sensors use ADC principle to read the sensor voltage to reflect whether combustible gas and toxic CO gas exist in the air currently, the MQ2 sensor is characterized as a sliding rheostat, the resistance of the sliding rheostat decreases with the increase of the gas concentration, the conductivity is the reciprocal of the resistance, and when the resistance of the output is lower, the conductivity increases with the increase of the resistance, and the output analog signal is larger. The MQ7 sensor can detect the CO concentration in the indoor environment to output high and low levels, so that the concentration is displayed.

As shown in fig. 1 and 7, when indoor air needs to be detected, the belt transmission assembly is started, that is, the fan body 23 fixed on the connecting shaft 21 can be rotated, here, the fan body 23 is preferably an air suction fan, so that air is sucked into the mounting sleeve 27, at this time, due to the effects of the first sensor 24 and the second sensor 26, the combustible gas and CO concentration in the air can be detected, and through the effect of the screw rod adjusting assembly, the movable block 6 can be moved up and down, so that the first sensor 24 and the second sensor 26 where the detection assembly fixed on the movable block 6 is located can detect the air at different heights, in this process, through the power provided by the belt transmission assembly, the fan body 23 where the detection assembly is located can be operated, and through the effects of the first sensor 24 and the second sensor 26, the effects of the screw rod transmission assembly are matched, that air is sucked and detected at different height positions, so that the accuracy of gas detection is further improved.

Further, the screw adjusting assembly comprises a mounting groove 3, the mounting groove 3 is formed in the vertical section of the mounting frame 1, the screw adjusting assembly further comprises a stud 4 and a threaded sleeve 5, the threaded sleeve 4 is mounted in the mounting groove 3 and rotates, the threaded sleeve 5 is spirally connected to the outer wall of the stud 4, the threaded sleeve 5 is fixed with the movable block 6, and the top of the vertical section of the mounting frame 1 is further provided with a meshing driving assembly for controlling the rotation of the stud 4; the device also comprises second contact switches 34 respectively arranged at the bottom and the top of the mounting groove 3, and when the screw sleeve 5 touches, the second contact switches 34 are used for regulating and controlling the operation of the meshing driving component.

Because the swivel nut 5 is fixed with the movable block 6, and the swivel nut 5 is screwed connection with the stud 4 again, therefore, through the power that the meshing drive subassembly provided, as shown in fig. 1, when the stud 4 rotates, can make the movable block 6 reciprocate, thereby make the detection subassembly that sets up on the movable block 6 reciprocate, and again because set up the second contact switch 34 at mounting groove 3 bottom and top respectively, as the stud 4 rotates, make the swivel nut 5 touch the second contact switch 34 at mounting groove 3 bottom or top, can realize the automatic regulation and control process of meshing drive subassembly, thereby make the rotation direction of stud 4 change, thereby make swivel nut 5 backward movement, this process is through two second contact switches 34 that set up, can realize the automatic regulation and control of meshing drive subassembly, thereby realize an automatic function that turns to of movable block 6, and then realize the automation of detection subassembly position adjustment.

Furthermore, the meshing driving assembly comprises a connecting column arranged at the top end of the stud 4, one end of the connecting column penetrates through a through hole formed in the mounting frame 1 and is fixedly connected with the top of the stud 4, and a second transmission gear 13 fixed at the other end of the connecting column; the movable frame 38 is arranged at the top of the vertical section mounting frame 1, the two ends of the movable frame 38 are respectively provided with a first motor 11 and a first transmission tooth 12 fixed at the output end of the first motor 11, and the first transmission tooth 12 is meshed with the second transmission tooth 13; the device also comprises two first contact switches 10 arranged at the top of the vertical section of the mounting frame 1, wherein when the movable frame 38 is in contact with the first contact switches 10, the first contact switches 10 are used for driving the first motor 11 to run; the groove 9 is formed in the top of the vertical section of the mounting frame 1, the electric telescopic rod 36 is arranged on the inner wall of the groove 9, and the telescopic end of the electric telescopic rod 36 is fixed with the movable frame 38 through a fixing piece and used for driving the movable frame 38 to run.

Two first driving teeth 12 arranged at the top of the mounting frame 1 are opposite in rotating direction, two first contact switches 10 arranged at the top of the mounting frame 1 are respectively used for driving first motors 11 at opposite sides, the first driving teeth 12 are meshed with second driving teeth 13, the second driving teeth 13 are fixedly connected with studs 4, an electric telescopic rod 36 is connected with the first driving teeth 12 through a movable frame 38, therefore, when a screw sleeve 5 where a screw rod adjusting component is located touches a second contact switch 34 at the bottom or the top of the mounting groove 3, the electric telescopic rod 36 can be made to move telescopically, so that the second driving teeth 13 are controlled to be in contact with the first driving teeth 12 corresponding to the first motors 11, as shown in specific figures 2 and 3, when the screw sleeve 5 moves to the bottom or the top and is in contact with the second contact switch 34 at a corresponding position, the electric telescopic rod 36 can be made to move telescopically correspondingly, so that the second driving teeth 13 are meshed with one of the first motors 11 arranged on the movable frame 38, meanwhile, the side wall of the movable frame 38 can be in contact with the first contact switch 10 at the opposite sides, so that the first driving teeth 13 and the stud 12 can be intermittently rotated, and the first driving teeth can be intermittently and the first driving teeth 13 can be intermittently rotated, so that the stud 12 can be intermittently and the stud 12 and the stud is driven to rotate when the stud is started.

Further, the belt transmission assembly comprises a mounting plate 20 fixed on the horizontal section of the mounting frame 1, and a second motor 19 arranged in front of the mounting plate 20, and a fourth transmission wheel 18 is fixed at the output end of the second motor 19; the device also comprises a third driving wheel 17 which is rotationally connected with the front part of the movable block 6 through a mounting shaft; the first driving wheel 8 is fixed at one end, far away from the fan body 23, of the connecting shaft 21 where the detection assembly is located; and a second driving wheel 14 rotatably connected to the upper part of the vertical section of the mounting frame 1 through a pin 15; and a transmission belt 16 which is in transmission connection among the fourth transmission wheel 18, the third transmission wheel 17, the first transmission wheel 8 and the second transmission wheel 14.

As shown in fig. 1, when the movable block 6 is at any position, the fan body 23 where the detection mechanism is located can be rotated by the power provided by the second motor 19 and the action of the transmission belt 16, that is, the air suction detection at different positions of the movable block 6 is completed.

Further, the side wall of the vertical section of the mounting bracket 1 is also provided with a control panel 7.

As shown in fig. 1, in this embodiment, a single chip microcomputer is disposed inside the control panel 7, and the control panel 7 is electrically connected to the MQ2 sensor and the MQ7 sensor, respectively, when the MQ2 sensor and the MQ7 sensor detect abnormal indoor air, the signal is transmitted to the single chip microcomputer inside the control panel 7, and at this time, the single chip microcomputer receives the signal and gives a warning, so as to inform a user in time, and reduce the possibility of dangerous accidents.

As the utility model discloses a another kind of embodiment, the singlechip can be connected with the exhaust fan pin electricity of indoor setting, when indoor harmful gas exceeds standard, MQ2 sensor and MQ7 sensor pass the signal to the singlechip promptly for the high-speed operation of single chip microcomputer control exhaust fan, thereby outdoor with gas outgoing, make the indoor air quality obtain promoting, reduce toxic gas to user's influence.

Furthermore, the outer wall of the vertical section of the mounting rack 1 is also provided with an alarm 37 for warning that toxic gas exceeds the standard.

The alarm 37 is preferably a buzzer, and the alarm 37 is electrically connected to the single chip microcomputer inside the control panel 7, as shown in fig. 4, when the single chip microcomputer receives the air abnormal signals sent by the MQ2 sensor and the MQ7 sensor, the alarm 37 is controlled to be started, so that the alarm is sent out, the user is further warned that the harmful gas exceeds the standard,

further, a purifying box 28 is fixed on the side wall of the threaded sleeve 5 far away from the movable block 6, the side wall of the purifying box 28 is communicated with a conduit, and the conduit sequentially passes through holes respectively formed in the threaded sleeve 5 and the movable block 6 and extends into the mounting sleeve 27; and a step part which is arranged on the side wall of the purifying box 28 far away from the conduit, and an air purifying layer 29 is arranged on the step part and is used for purifying harmful gas; the side wall of the purifying box 28 far away from the conduit is also provided with an elastic limiting component, and a mounting ring 35 arranged at the end part of the elastic limiting component is used for limiting and mounting the air purifying layer 29; and further includes an open slot 32 formed in the bottom of the purge bin 28.

As shown in fig. 2 and 6, when the air purification layer 29 needs to be installed, the air purification layer 29 can be inserted into the step portion where the purification box 28 is located through the open slot 32 formed in the bottom of the purification box 28, the installation ring 35 is tightly abutted against the side wall of the air purification layer 29 under the action of the elastic limiting component, so that the air purification layer 29 can be installed in a limited manner, and when the elastic limiting component is pulled in the same manner, the air purification layer 29 can be detached, and harmful gas entering the interior of the purification box 28 through a conduit can be purified through the action of the air purification layer 29, so that the indoor air quality is further improved.

Furthermore, the elastic limiting assembly comprises a mounting bar 31 fixed on the side wall of the purification box 28 and a movable frame 30 which passes through holes respectively formed at two ends of the mounting bar 31 and can move in the through holes in a telescopic manner, and the end part of the movable frame 30 is fixed with the mounting ring 35; a plurality of springs 33 are connected between the inner top of the mounting bar 31 and the side wall of the movable frame 30.

Because the movable frame 30 can move on the mounting bar 31 in a telescopic manner, and the spring 33 is matched, as shown in fig. 2 and fig. 6, when the air purification layer 29 needs to be replaced, the movable frame 30 can be pulled outwards, and the spring 33 is compressed, so that the mounting ring 35 fixed at the end of the movable frame 30 is separated from the air purification layer 29, the air purification layer 29 slides out from the open slot 32 at the bottom of the purification box 28, namely, the detachment process of the air purification layer 29 is completed, similarly, when the movable frame 30 is pulled outwards, the air purification layer 29 enters the step part of the purification box 28 through the open slot 32, and then the hand is loosened, so that the mounting ring 35 is tightly abutted against the air purification layer 29, and the replacement of the air purification layer 29 is completed.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," and "fixed" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The detachable installation mode has various modes, for example, the detachable installation mode can be matched with a buckle through inserting, for example, a bolt connection mode and the like.

The conception, the specific structure, and the technical effects produced by the present invention are clearly and completely described above in conjunction with the embodiments and the accompanying drawings, so as to fully understand the objects, the features, and the effects of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all embodiments, and other embodiments obtained by those skilled in the art without inventive labor based on the embodiments of the present invention all belong to the protection scope of the present invention. In addition, all the coupling/connection relationships mentioned herein do not mean that the components are directly connected, but mean that a better coupling structure can be formed by adding or reducing coupling accessories according to specific implementation conditions.

The above embodiments are only used for further explanation of the present invention, and it is not understood that the present invention is limited by the protection scope of the present invention, and the technical engineers in the field are right according to the above contents of the present invention.

Claims

1. A harmful gas detection apparatus, characterized by comprising:

a mounting frame (1);

the sliding chute (2) is formed in the vertical section of the mounting rack (1), and a movable block (6) which can slide up and down is arranged in the sliding chute (2) and is used for detecting gases at different height positions;

and a detection assembly arranged on the movable block (6) and used for sucking and detecting harmful gases;

the detection assembly comprises a mounting sleeve (27), the mounting sleeve (27) is fixedly connected with the side wall where the movable block (6) is located, and a second mounting frame (25) is fixed inside the mounting sleeve (27), and a first sensor (24) and a second sensor (26) are arranged on the second mounting frame (25);

the air purifier is characterized by further comprising a first mounting frame (22) fixed at the front end of the mounting sleeve (27), the middle of the first mounting frame (22) is rotatably connected with a connecting shaft (21), and one end, close to the second mounting frame (25), of the connecting shaft (21) is fixedly provided with a fan body (23) for air to be pumped in;

the screw adjusting component is arranged at the vertical section of the mounting rack (1) and is used for driving the movable block (6) to operate;

still including setting up belt drive assembly on mounting bracket (1), work as movable block (6) move, belt drive assembly drives fan body (23) work.

2. The harmful gas detection apparatus according to claim 1, wherein: the screw rod adjusting component comprises a mounting groove (3), the mounting groove (3) is arranged on the vertical section of the mounting rack (1), the screw rod adjusting component also comprises a stud (4) which is mounted in the mounting groove (3) and rotates at the top, and a screw sleeve (5) which is spirally connected with the outer wall of the stud (4), and the screw sleeve (5) is fixed with a movable block (6),

the top of the vertical section of the mounting rack (1) is also provided with an engaging driving assembly for controlling the rotation of the stud (4);

the mounting groove structure is characterized by further comprising second contact switches (34) which are arranged at the bottom and the top of the mounting groove (3) respectively, and when the screw sleeve (5) is touched, the second contact switches (34) are used for regulating and controlling the operation of the meshing driving assembly.

3. The harmful gas detection apparatus according to claim 2, wherein: the meshing driving assembly comprises a connecting column arranged at the top end of the stud (4), one end of the connecting column penetrates through a through hole formed in the mounting frame (1) and is fixedly connected with the top of the stud (4), and a second transmission gear (13) fixed at the other end of the connecting column;

the movable frame (38) is arranged at the top of the vertical section mounting frame (1), two ends of the movable frame (38) are respectively provided with a first motor (11) and a first transmission gear (12) fixed at the output end of the first motor (11), and the first transmission gear (12) is meshed with the second transmission gear (13);

the device also comprises two first contact switches (10) arranged at the top of the vertical section of the mounting frame (1), and when the movable frame (38) is in contact with the first contact switches (10), the first contact switches (10) are used for driving the first motor (11) to run;

and the groove (9) is formed in the top of the vertical section of the mounting frame (1), the electric telescopic rod (36) is arranged on the inner wall of the groove (9), and the telescopic end of the electric telescopic rod (36) is fixed with the movable frame (38) through a fixing piece and is used for driving the movable frame (38) to run.

4. The harmful gas detection apparatus according to claim 1, wherein: the belt transmission assembly comprises an installation plate (20) fixed on the horizontal section of the installation frame (1) and a second motor (19) arranged on the front part of the installation plate (20), and a fourth transmission wheel (18) is fixed at the output end of the second motor (19);

the device also comprises a third driving wheel (17) which is rotationally connected with the front part of the movable block (6) through a mounting shaft;

the first transmission wheel (8) is fixed at one end, far away from the fan body (23), of the connecting shaft (21) where the detection assembly is located;

a second driving wheel (14) is rotatably connected to the upper part of the vertical section of the mounting rack (1) through a pin shaft (15);

and the transmission belt (16) is in transmission connection among the fourth transmission wheel (18), the third transmission wheel (17), the first transmission wheel (8) and the second transmission wheel (14).

5. The harmful gas detection apparatus according to claim 1, wherein: the side wall of the vertical section of the mounting rack (1) is also provided with a control panel (7).

6. The harmful gas detection apparatus according to claim 1, wherein: the outer wall of the vertical section of the mounting frame (1) is further provided with a warning indicator (37) for warning that toxic gas exceeds the standard.

7. The harmful gas detection apparatus according to claim 2, wherein: a purifying box (28) is fixed on the side wall of the threaded sleeve (5) far away from the movable block (6), the side wall of the purifying box (28) is communicated with a conduit, and the conduit sequentially penetrates through holes respectively formed in the threaded sleeve (5) and the movable block (6) and extends into the mounting sleeve (27);

and a step part which is arranged on the purifying box (28) and is far away from the side wall of the conduit, wherein an air purifying layer (29) is arranged on the step part and is used for purifying harmful gas;

the side wall of the purifying box (28) far away from the guide pipe is also provided with an elastic limiting assembly and a mounting ring (35) arranged at the end part of the elastic limiting assembly, and the elastic limiting assembly is used for limiting and mounting the air purifying layer (29);

also comprises an open slot (32) arranged at the bottom of the purifying box (28).

8. The harmful gas detection apparatus according to claim 7, wherein: the elastic limiting assembly comprises a mounting bar (31) fixed on the side wall of the purifying box (28) and a movable frame (30) which penetrates through holes formed in two ends of the mounting bar (31) respectively and can move in the through holes in a telescopic mode, and the end portion of the movable frame (30) is fixed with a mounting ring (35);

a plurality of springs (33) are connected between the inner top of the mounting bar (31) and the side wall of the movable frame (30).