CN114688657B

CN114688657B - Laboratory ventilation system

Info

Publication number: CN114688657B
Application number: CN202210249770.4A
Authority: CN
Inventors: 吴奕剑
Original assignee: Zhejiang Hongxiang Education Equipment Co ltd
Current assignee: Zhejiang Hongxiang Education Equipment Co ltd
Filing date: 2022-03-14
Publication date: 2024-05-31
Anticipated expiration: 2042-03-14

Abstract

The invention discloses a laboratory ventilation system, which comprises a shell, a ventilation hole arranged on the shell, and an exhaust pipe arranged on the shell and butted with the ventilation hole, wherein the shell comprises a first section, a middle section and a tail section, the first section, the middle section and the tail section are sequentially connected to form the shell, and a dust cover is arranged on the shell; the first section and the tail section have the same structure, and two ends of the middle section are respectively connected with the first section and the tail section; the vent holes are positioned on the first section and the tail section, and the exhaust pipe is connected to the vent holes on the first section or the tail section in a turnover way; the dustproof cover is connected to the shell in a turnover way so as to form or release the cover of the exhaust pipe in cooperation with the shell, a space for placing the exhaust pipe is arranged between the dustproof cover and the shell, and when the dustproof cover is covered with the shell, the dustproof cover and the shell are matched to cover the exhaust pipe; one side of the dust cover connected with the shell is connected with any two or three sections of the first section, the middle section and the tail section. The invention is convenient for production, reduces cost, and simultaneously can improve dustproof effect and reduce influence on experiments.

Description

Laboratory ventilation system

Technical Field

The present invention relates to laboratory ventilation systems.

Background

The laboratory is the place where the test is performed. The laboratory is a scientific cradle, is a base for scientific research, is a source of scientific development, and plays a very important role in the scientific development.

All can set up the laboratory in teaching and research all kinds of institutions, and carry out the experiment in the laboratory, need have good experimental environment including ventilation, power supply, exhaust etc. for example in chemical experiment, just have very high requirement to exhaust, otherwise produce toxic gas easily, cause the potential safety hazard to the experimenter.

The utility model patent of China with the prior art application number CN202021833490.0 discloses an intelligent top centralized supply device for a laboratory, which comprises a shell and a top plate; a top plate is fixedly arranged in the middle of the top end of the shell; and a plurality of groups of vent holes are symmetrically communicated with the two sides of the bottom end of the shell. Because the control block needs to be installed, the control block is installed on the shell through the connecting rod, and the connecting rod is stored through the form of upset, the text and the attached drawing of this prior art can know that the shell of this scheme needs the length of cooperation connecting rod to set up, because the length of connecting rod is very long, consequently need very big mould to process production when producing the shell, lead to the mould cost very high, and this kind of large-scale mould transport difficulty is unfavorable for enterprise production moreover.

Moreover, the exhaust pipe in the prior art cannot be stored better, dust deposition of the exhaust pipe is easy to cause, and laboratory staff needs to wipe the exhaust pipe frequently, otherwise, when the exhaust pipe is operated, dust falls into experimental equipment easily, and experimental effect is influenced.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a laboratory ventilation system which is convenient to produce, reduces cost, and simultaneously can improve the dustproof effect and reduce the influence on experiments.

In order to achieve the above purpose, the present invention provides the following technical solutions: the laboratory ventilation system comprises a shell, a ventilation hole arranged on the shell, and an exhaust pipe arranged on the shell and butted with the ventilation hole, wherein the shell comprises a first section, a middle section and a tail section, the first section, the middle section and the tail section are sequentially connected to form the shell, and a dust cover is arranged on the shell; the structure of the first section and the tail section is the same, and two ends of the middle section are respectively connected with the first section and the tail section; the ventilation holes are positioned on the first section and the tail section, and the exhaust pipe is connected to the ventilation holes on the first section or the tail section in a turnover way;

the dustproof cover is connected to the shell in a turnover way so as to be matched with the shell to form or release the cover of the exhaust pipe, a space for placing the exhaust pipe is arranged between the dustproof cover and the shell, and when the dustproof cover is covered with the shell, the dustproof cover and the shell are matched with each other to cover the exhaust pipe;

one side of the dust cover connected with the shell is connected with any two or three sections of the first section, the middle section and the tail section.

As a further improvement of the invention, the head section, the middle section and the tail section are provided with lamp slots which are communicated in sequence and used for installing the lamp tubes or the lamp strips, and the lamp slots are positioned towards the dust cover; the dust covers are positioned on two sides of the shell; the side surface of the dustproof cover, which faces the lamp tube or the lamp belt, is a reflecting surface for reflecting the lamplight of the lamp tube or the lamp belt.

As a further improvement of the invention, the head section and the tail end are provided with electric driving components for driving the dust cover to rotate; and a detection component for detecting the dust cover to rotate in place is arranged on the first section, the middle section or the tail section, and the detection component is linked with the electric driving component and used for controlling the electric driving component to stop acting.

As a further improvement of the invention, the middle section is of a central symmetrical structure; the tail section and/or the middle section are/is connected with a connecting plate which is used for connecting the middle section and the tail section; the shells are connected through middle sections to form an extension structure; the adjacent first section and the tail section between the shells are connected together through the middle section, the number of the connecting plates is a plurality of, the connecting plates are arranged on the first section, the tail section and the middle section on two adjacent shells connected through the middle section, and the first section and the middle section and the tail section and the middle section are mutually assembled through the two connecting plates.

As a further improvement of the invention, the exhaust pipe comprises a pipeline and a fan cover arranged on the pipeline; the pipeline is a spiral corrugated pipe, a through hole is formed in the joint of the fan housing and the pipeline, threads matched with the spiral corrugation of the pipeline are arranged on the inner wall of the through hole, and the fan housing is in threaded connection with the pipeline through the threads.

As a further improvement of the invention, the pipeline is also connected with a telescopic pipe, and a connecting piece for adapting to the spiral corrugation of the pipeline is arranged in the telescopic pipe; the pipeline is in threaded connection with the connecting piece through threaded adaptation; the connecting piece is annular, the diameter of the connecting piece is matched with the inner diameter of the telescopic pipe, and the connecting piece is installed in the telescopic pipe through interference fit.

As a further improvement of the invention, the telescopic pipe is also provided with a limiting piece for limiting the connecting piece from falling out, and the limiting piece is sleeved on the telescopic pipe and is connected with the telescopic pipe; the limiting piece is provided with an opening for the pipe to extend out, and the opening is smaller than the connecting piece so as to limit the connecting piece from being separated from the telescopic pipe.

As a further improvement of the invention, the limiting piece is provided with a clamping block, the telescopic pipe is provided with a clamping groove at the position corresponding to the clamping block, and the limiting piece is clamped with the telescopic pipe through the clamping block and the clamping groove; and a transition inclined plane is arranged on one side of the clamping block facing the telescopic pipe.

As a further improvement of the invention, the side wall of the connecting piece is provided with a through hole for installing a bolt, and the connecting piece and the pipeline are locked with the bolt in a matching way through the through hole; the bolt is in threaded connection with the through hole; the through hole for installing the bolt on the connecting piece is positioned at the junction of the bulge and the recess of the internal thread of the connecting piece.

As a further improvement of the invention, a step is arranged in the through hole for installing the pipeline, and when the fan housing and the pipeline are installed in place, the pipeline is propped against the step.

The invention has the beneficial effects that:

1. The shell structure is divided into three sections, namely a first section, a middle section and a tail section, wherein the structures of the first section and the tail section are the same, only one mold is required to be adopted for production, and the middle section adopts another mold, so that the production difficulty is reduced, the cost of the mold can be reduced, and the production of three sections can be completed only by two molds with smaller volumes.

2. The segmented form also reduces the losses caused by the poorly formed product, and only some of the components are lost, not the entire set of shells.

3. The dust cover moves to cover the exhaust pipe, thereby playing a role in dust prevention.

4. Wherein the exhaust pipe cooperates with the ventilation hole, can realize the effect of airing exhaust to have the extension effect, can utilize the exhaust pipe to aim at the position that needs to be aired exhaust, with harmful gas exhaust, let the experimentation safer.

5. After covering the exhaust pipe, the air exhaust pipe can also have an attractive effect, and the exposure of parts is reduced.

Drawings

FIG. 1 is a perspective view of the overall structure of the present invention;

FIG. 2 is a schematic view of a dust cap according to the present invention;

FIG. 3 is a schematic perspective view of a housing structure according to the present invention;

FIG. 4 is a schematic front view of the housing structure of the present invention;

FIG. 5 is a schematic view of an extension structure of the housing of the present invention;

FIG. 6 is a schematic view of a connecting plate according to the present invention;

FIG. 7 is a schematic view of the exhaust duct according to the present invention;

FIG. 8 is a schematic cross-sectional view of an exhaust duct according to the present invention;

FIG. 9 is an enlarged schematic view of the portion A of FIG. 7;

FIG. 10 is an enlarged schematic view of the portion B of FIG. 8;

FIG. 11 is an enlarged schematic view of the structure of portion C of FIG. 8;

reference numerals: 1. a housing; 11. a first section; 12. a middle section; 13. a tail section; 14. a lamp groove; 15. a light strip; 16. an electric driving part; 17. a detection section; 18. a connecting plate; 2. a vent hole; 3. an exhaust pipe; 31. a pipe; 32. a fan housing; 33. a telescopic tube; 34. a connecting piece; 35. a limiting piece; 351. a clamping block; 352. a transition inclined plane; 36. a clamping groove; 37. a step; 4. a dust cover.

Detailed Description

The invention will be further described in detail with reference to examples of embodiments shown in the drawings.

As shown with reference to figures 1-11,

The laboratory ventilation system comprises a shell 1, a ventilation hole 2 arranged on the shell 1 and an exhaust pipe 3 arranged on the shell and butted with the ventilation hole 2, and is characterized in that the shell 1 comprises a first section 11, a middle section 12 and a tail section 13, the first section 11, the middle section 12 and the tail section 13 are sequentially connected to form the shell, and a dust cover 4 is arranged on the shell; the structure of the head section 11 and the tail section 13 is the same, and two ends of the middle section 12 are respectively connected with the head section 11 and the tail section 13; the ventilation holes 2 are positioned on the first section 11 and the tail section 13, and the exhaust pipe 3 is connected at the ventilation holes 2 on the first section 11 or the tail section 13 in a reversible manner;

The dustproof cover 4 is connected to the shell in a turnover way so as to be matched with the shell to form or release the cover of the exhaust pipe 3, a space for placing the exhaust pipe 3 is arranged between the dustproof cover 4 and the shell, and when the dustproof cover 4 is covered with the shell, the dustproof cover 4 is matched with the shell to cover the exhaust pipe 3;

one side of the dust cover 4 connected with the shell is connected with any two or three sections of the first section 11, the middle section 12 and the tail section 13.

The existing laboratory ventilation system adopts the casing 1 that is integrated into one piece at present, because holistic casing 1 length is very long, promotes the degree of difficulty to mould and production process. This scheme is divided into three with casing 1 structure, is first section 11, middle section 12, tail section 13 respectively, and wherein first section 11 and tail section 13's structure is the same, only need adopt same mould to produce can, and middle section 12 adopts another mould, has reduced the degree of difficulty of production on the one hand to can also reduce the cost of mould, only need two moulds all the mould that the volume is less can accomplish the production of three segmentation. Wherein the two ends of the middle section 12 are connected with the first section 11 and the tail section 13 to form an integral shell. And the segment form can also reduce the loss caused by products with poor molding effect, only part of the components in the products can be lost, and the whole set of shells can not be lost.

Because the first section 11 and the tail section 13 have the same structure, in order to make the middle section 12 and the two ends fit and install better, the middle section 12 is preferably arranged to be a central symmetrical structure. At this time, the two ends of the middle section 12 can be assembled with the first section 11 and the tail section 13, so that the assembly is more convenient, and the corresponding relation between the two ends of the middle section 12 does not need to be distinguished. That is, only two first sections 11 (tail sections 13) and one middle section 12 are needed to be arbitrarily taken to assemble the housing 1. To facilitate the connection between two adjacent segments, a connecting piece 34 is connected to the end segment 13 (head segment 11) and/or the middle segment 12, and the connecting piece 34 is used to connect the middle segment 12 and the end segment 13 (head segment 11). Because the middle section 12 is the central symmetry structure, the connecting piece 34 can adapt the both ends of middle section 12, and the structure of tail section 13 and first section 11 is unanimous simultaneously, consequently also can adapt tail section 13 and first section 11, and the connecting piece 34 of a specification can adapt the middle section 12 simultaneously with the connection of first section 11 and terminal and tail section 13's connection, need not prepare the excessive goods of kind when the equipment. A shell is formed by connecting a first section 11, a middle section 12 and a tail section 13, and the two devices can be connected through the middle section 12, namely, the two devices are connected at intervals, namely, the first section 11, the middle section 12, the tail section 13, the middle section 12, the first section 11, the middle section 12 and the tail section 13 are formed for infinite extension. The structure is favorable for keeping the test positions in the laboratory at equidistant intervals, and the length of the interval is the length of the middle section 12, so that the layout is more reasonable.

In order to improve the lighting effect and increase the dustproof effect of the lamp tube or the lamp strip 15, the first section 11, the middle section 12 and the tail section 13 are provided with lamp slots 14 which are sequentially communicated and used for installing the lamp tube or the lamp strip 15, and the lamp slots 14 are positioned towards the dustproof cover 4; the dust covers 4 are positioned on two sides of the shell; the side surface of the dust cover 4 facing the lamp tube or the lamp belt 15 is a reflecting surface for reflecting the lamp light of the lamp tube or the lamp belt 15.

The light and the lamp strip 15 are reflected through the light reflecting surface of the dust cover 4, so that the light and the lamp strip 15 can be reflected to the experiment table, a better illumination effect can be achieved, the problem that the illumination of the position where the lamp strip 15 is installed can be affected can be solved, and the installation mode of various lamp strips 15 can be adapted.

Alternatively, the reflective surface is a frosted surface for diffuse reflection. The light is reflected in a diffuse reflection mode, so that the light irradiation is softer, and the irradiation range can be enlarged.

Of course, alternatively, the lamp tube or the lamp belt 15 for illumination can be arranged on the housing at a position facing downwards and exposed in cooperation with the above scheme. Can provide brighter illuminating effect through this lamp area 15, select according to the experimenter actual need, when the higher illuminating effect of needs, can select to open the lamp area 15 of diffuse reflection effect and the lamp area 15 of high illuminating effect, both cooperations provide local high illuminating effect, whole big irradiation range.

The dust cover 4 can be manually turned over. But the mode of turning over the pull rope can be improved, the pull rope is hung on the dust cover 4, and the dust cover 4 is turned over upwards to open the dust cover 4 by pulling the pull rope. Of course, the invention may be modified to be electrically controlled, specifically, the head section 11 and the tail end are provided with an electric driving component 16 for driving the dust cover 4 to rotate; the head section 11, the middle section 12 or the tail section 13 is provided with a detection component 17 for detecting the rotation of the dust cover 4 in place, and the detection component 17 is linked with the electric driving component 16 and is used for controlling the electric driving component 16 to stop acting.

The dust cover 4 is driven by the electric driving part 16 to turn over, and the detection part 17 is matched for feedback, and the electric driving part 16 is controlled to stop driving after the detection part 17 detects that the dust cover 4 turns over to the proper position. The specific detection part 17 can adopt infrared detection, laser ranging, trigger switch and the like. The motor may be used as the motor for the electric driving member 16, and the dust cap 4 may be driven by providing a plurality of motors on the main body in synchronization with each other. The specific driving mode may be to drive the hinge shaft of the dust cover 4, and drive the dust cover by using a gear engagement mode. And the detection part 17 can be in a closed position or an open position. The detection component 17 can be set at a corresponding place by a person skilled in the art according to a required detection mode, and the specific setting position is selected by the person skilled in the art according to the requirement, and will not be described in detail herein.

Of course, the detecting component 17 may also adopt a hall switch, and detect the turnover degree of the dust cover 4 through a magnetic induction mode, for example, a magnet is attached to the dust cover 4, the hall switch is installed on the main body, when the dust cover 4 is opened in place, the magnet is close to the dust cover 4, and the hall switch is fed back in place, and at this time, the motor-driven driving component 16 stops driving action; similarly, in-place feedback can be achieved when the dust cap 4 is flipped down.

In order to be convenient to install, the ventilation system can be installed at equal intervals, and the attractive appearance is also improved. The tail section 13 and/or the middle section 12 are/is connected with a connecting plate 18, and the connecting plate 18 is used for connecting the middle section 12 and the tail section 13; a plurality of shells are connected through a middle section 12 to form an extension structure; the first section 11 and the tail section 13 between the adjacent shells are connected together through the middle section 12, the number of the connecting plates 18 is multiple, the connecting plates 18 are arranged on the first section 11, the tail section 13 and the middle section 12 on two adjacent shells connected through the middle section 12, and the first section 11 and the middle section 12 and the tail section 13 and the middle section 12 are mutually assembled through the two connecting plates 18.

In a further preferred embodiment, the exhaust duct 3 includes a duct 31 and a fan housing 32 mounted on the duct 31; the pipeline 31 is a spiral corrugated pipe, a through hole is formed in the joint of the fan housing 32 and the pipeline 31, threads matched with the spiral corrugation of the pipeline 31 are arranged on the inner wall of the through hole, and the fan housing 32 is in threaded connection with the pipeline 31 through thread matching.

The pipe 31 adopts the helical bellows, and compared with the common bellows, the corrugated shape of the helical bellows has a threaded effect, and the helical bellows is in threaded installation with the fan housing 32 by means of the threaded effect, so that the pipe 31 has an angle-changeable effect, and can be rapidly installed with the fan housing 32, and the installation characteristic without tools is realized. And screw thread cooperation possesses good sealed effect, compares in traditional connected mode also can reduce the air leakage, lets the effect of airing exhaust more stable, obvious.

As a further optimization scheme, a step 37 is arranged in a through hole of the fan housing 32 for installing the pipeline 31, and when the fan housing 32 and the pipeline 31 are installed in place, the pipeline 31 abuts against the step 37.

Wherein the provision of the step 37 contributes to the formation of a sealing fit, for example a rubber gasket on the step 37, can increase the sealing effect. The step 37 can be attached to the end of the pipe 31 to provide a better sealing effect without a rubber gasket, and the user can be prompted to assemble the pipe 31 in place, so that the pipe 31 cannot be rotated when the user rotates the fan housing 32 to install the pipe 31 in place, and the user can be prompted to assemble the pipe 31 in place.

Specifically, in order to make the exhaust function more flexible, the pipe 31 is further connected with a telescopic pipe 33, and a connecting piece 34 for adapting to the spiral corrugation of the pipe 31 is arranged in the telescopic pipe 33; the pipe 31 is in threaded connection with the connecting piece 34 through threaded fit; the connecting piece 34 is annular, the diameter of the connecting piece is matched with the inner diameter of the telescopic pipe 33, and the connecting piece 34 is installed in the telescopic pipe 33 through interference fit.

The pipe 31 and the telescopic pipe 33 are installed by means of spiral corrugation, so that the assembly effect can be kept fast and stable. The direct threading of the inner wall of the bellows 33 results in a thinning of the inner wall, if the strength is to be maintained, the wall thickness is to be increased, at which time the cost and the weight are to be increased considerably, in the case of an increased weight, the problem of difficult operation occurs when the bellows 33 is operated, and in the case of an increased weight, the bellows 33 is to be caused to automatically extend under the action of gravity, resulting in a difficulty in control, and the problem needs to be overcome by means of other structures. In this scheme, the pipeline 31 is connected by the connecting piece 34, and then is connected in the telescopic pipe 33 by the connecting piece 34, and the connecting mode can be connected by adopting a mode of connecting the connecting piece 34 and the telescopic pipe 33 by bolts, and can also be connected by adopting a mode of expansion fit or interference fit. The interference fit mode is simple in connection, simple in structure and convenient to assemble, and production and assembly efficiency can be improved.

In order to make the effect of interference fit more stable, the telescopic tube 33 is further provided with a limiting piece 35 for limiting the connecting piece 34 from falling out, and the limiting piece 35 is sleeved on the telescopic tube 33 and connected with the telescopic tube 33; the limiting member 35 has an opening through which the pipe 31 is extended, and is smaller than the connecting member 34 to limit the escape of the connecting member 34 from the telescopic pipe 33.

Because the opening of the limiting piece 35 is smaller than the size of the connecting piece 34, the connecting piece 34 can be limited to be separated from the opening of the limiting piece 35, the limiting piece 35 and the telescopic pipe 33 are utilized to install, the connecting piece 34 can be limited in the telescopic pipe 33, and the phenomenon that the pipeline 31 is separated due to excessively hard pulling of the pipeline 31 when a user stretches and contracts is avoided. Alternatively, the connection between the limiting member 35 and the telescopic tube 33 may be performed by a bolt assembly manner or a clamping manner.

In the preferred scheme, the limiting piece 35 is connected with the telescopic pipe 33 in a clamping manner, specifically speaking, a clamping block 351 is arranged on the limiting piece 35, a clamping groove 36 is arranged on the telescopic pipe 33 corresponding to the clamping block 351, and the limiting piece 35 is clamped with the telescopic pipe 33 through the clamping block 351 and the clamping groove 36.

The clamping groove 36 arranged on the telescopic pipe 33 can be through or in a blind hole form. The clamping block 351 is matched with the clamping groove 36, and when the limiting piece 35 is installed on the telescopic pipe 33, the clamping groove 36 is clamped with the clamping block 351, so that the limiting piece 35 is limited to fall off. The clamping mode also does not need tools, so that the device has the characteristic of quick assembly in the assembly process.

In order to ensure a more rapid plugging and locking of the stop 35 to the telescopic tube 33, a transition bevel 352 is provided on the side of the clamping block 351 facing the telescopic tube 33. By using the transition inclined plane 352, the stop member 35 and the telescopic tube 33 can be inserted and connected without being blocked, and the telescopic tube 33 and the stop member 35 can be assembled without being blocked by using the guiding function of the inclined plane.

Because the connection between the connector 34 and the pipe 31 is simply made by threaded engagement, it can cause the operator to unscrew in the event of a malfunction. The connecting piece 34 is connected with the bolt through the through hole in a bolt matching mode, the bolt is connected with the connecting piece 34 through threads, and the pipeline 31 is locked through a clamping mode, so that the resistance can be increased, the rotation difficulty of the pipeline 31 is increased, and further the situation that a user carelessly rotates the pipeline 31 to fall off is reduced. In order to make the locking effect of the bolt more stable, the through hole for installing the bolt on the connecting piece 34 is located at the juncture of the protrusion and the recess of the internal thread of the connecting piece 34. The protruding and sunken juncture of screw thread possesses better intensity to can let pipeline 31 produce certain surface deformation, more conveniently let bolt and pipeline 31 form locking cooperation.

The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above examples, and all technical solutions belonging to the concept of the present invention belong to the protection scope of the present invention. It should be noted that modifications and adaptations to the present invention may occur to one skilled in the art without departing from the principles of the present invention and are intended to be within the scope of the present invention.

Claims

1. The laboratory ventilation system comprises a shell, a ventilation hole arranged on the shell, and an exhaust pipe arranged on the shell and butted with the ventilation hole, and is characterized in that the shell comprises a first section, a middle section and a tail section, the first section, the middle section and the tail section are sequentially connected to form the shell, and a dust cover is arranged on the shell; the structure of the first section and the tail section is the same, and two ends of the middle section are respectively connected with the first section and the tail section; the ventilation holes are positioned on the first section and the tail section, and the exhaust pipe is connected to the ventilation holes on the first section or the tail section in a turnover way;

One side of the dust cover connected with the shell is connected with any two or three sections of the first section, the middle section and the tail section;

The head section, the middle section and the tail section are provided with lamp slots which are communicated in sequence and used for installing lamp tubes or lamp bands, and the lamp slots are positioned towards the dust cover; the dust covers are positioned on two sides of the shell; the side surface of the dustproof cover, which faces the lamp tube or the lamp belt, is a reflecting surface for reflecting the lamplight of the lamp tube or the lamp belt.

2. The laboratory ventilation system according to claim 1, wherein the head section and the tail section are provided with electric driving components for driving the dust cover to rotate; and a detection component for detecting the dust cover to rotate in place is arranged on the first section, the middle section or the tail section, and the detection component is linked with the electric driving component and used for controlling the electric driving component to stop acting.

3. The laboratory ventilation system according to claim 1, wherein the middle section is of a centrosymmetric structure; the tail section and/or the middle section are/is connected with a connecting plate which is used for connecting the middle section and the tail section; the shells are connected through middle sections to form an extension structure; the adjacent first section and the tail section between the shells are connected together through the middle section, the number of the connecting plates is a plurality of, the connecting plates are arranged on the first section, the tail section and the middle section on two adjacent shells connected through the middle section, and the first section and the middle section and the tail section and the middle section are mutually assembled through the two connecting plates.

4. The laboratory ventilation system according to claim 1, wherein the exhaust duct comprises a duct and a hood mounted on the duct; the pipeline is a spiral corrugated pipe, a through hole is formed in the joint of the fan housing and the pipeline, threads matched with the spiral corrugation of the pipeline are arranged on the inner wall of the through hole, and the fan housing is in threaded connection with the pipeline through the threads.

5. The laboratory ventilation system according to claim 4, wherein the duct is further connected with a telescopic tube having a connection therein for adapting to the helical corrugation of the duct; the pipeline is in threaded connection with the connecting piece through threaded adaptation; the connecting piece is annular, the diameter of the connecting piece is matched with the inner diameter of the telescopic pipe, and the connecting piece is installed in the telescopic pipe through interference fit.

6. The laboratory ventilation system according to claim 5, wherein the telescopic tube is further provided with a limiting member for limiting the detachment of the connecting member, and the limiting member is sleeved on the telescopic tube and connected with the telescopic tube; the limiting piece is provided with an opening for the pipe to extend out, and the opening is smaller than the connecting piece so as to limit the connecting piece from being separated from the telescopic pipe.

7. The laboratory ventilation system according to claim 6, wherein the limiting piece is provided with a clamping block, a clamping groove is formed in the telescopic tube at a position corresponding to the clamping block, and the limiting piece is clamped with the telescopic tube through the clamping block and the clamping groove; and a transition inclined plane is arranged on one side of the clamping block facing the telescopic pipe.

8. Laboratory ventilation system according to claim 5 or 6 or 7, characterized in that the side walls of the connection piece are provided with through holes for mounting bolts, the connection piece and the pipe being locked with the bolts by means of the through holes; the bolt is in threaded connection with the through hole; the through hole for installing the bolt on the connecting piece is positioned at the junction of the bulge and the recess of the internal thread of the connecting piece.

9. Laboratory ventilation system according to claim 4 or 5 or 6 or 7, characterized in that the through hole of the hood for mounting the pipe is provided with a step, against which the pipe abuts when the hood is mounted in place.