CN217472997U - Welding flue gas collecting and processing system - Google Patents

Abstract

The utility model relates to a welding fume collecting and processing system, which comprises a dust remover and a fume pipeline, wherein the fume pipeline is provided with a plurality of pipeline connecting pipes which are communicated with the fume pipeline and are arranged at intervals along the left and right directions; the welding flue gas collecting and processing system further comprises a closed dust collecting chamber which is used for covering the outside of the part to be welded, wheels for moving the dust collecting chamber are arranged at the bottom of the dust collecting chamber, a dust collecting cover for absorbing the welding flue gas is arranged in the dust collecting chamber, an air taking pipe communicated with the dust collecting cover is further arranged on the dust collecting chamber, and the air taking pipe is used for being connected with different pipeline connecting pipes along with the movement of the dust collecting chamber. The utility model discloses effectively solved dust cage troublesome poeration among the prior art to because of the dust cage can not suck away the welding flue gas completely, and lead to welding flue gas diffusion, influence the healthy problem of welder.

Description

Welding flue gas collecting and processing system

Technical Field

The utility model relates to a welding flue gas collection processing system belongs to dust collector technical field.

Background

When welding is carried out by applying a welding process in industrial production, a large amount of welding smoke and gas are generated in the process of combining a welding material and a base material, wherein a large amount of gas and smoke are harmful to a human body, and when the concentration of the gas and smoke exceeds the allowable concentration, the physical health of a welder is seriously influenced, various respiratory and pneumoconiosis diseases are caused, so that the welding working environment must be purified, and the physical health of the welder is maintained.

At present, two main treatment modes of welding smoke and gas are provided, one mode is a small-sized movable welding smoke purifier which comprises a movable purifier main body, a dust collection cover and a flexible corrugated pipe connected between the movable purifier main body and the dust collection cover, so that the welding smoke and the gas of a flowing welding point are collected and treated through the movable purifier main body; the other kind is to adopt fixed welding smoke and dust clarifier, and this kind of clarifier includes dust cage, flue gas pipeline and filter cylinder dust remover, and wherein, flue gas pipeline and filter cylinder dust remover link to each other, and the dust cage links to each other through flexible bellows with following between its pipeline, and welding smoke and dust and gas of fixed station can only be handled to this kind of clarifier.

However, for some order type engineering enterprises, because the size specification of the parts is huge, and at least one or all of the length, width and height of the parts to be welded is more than one meter, and the largest part is even twenty meters, when the parts with huge size specification are welded, the welding area is large, and when the range of laying the parts in a workshop is large, a large batch of welding production can be performed in hundreds of even thousands of square meters of welding area in the workshop, namely the welding area is also large. No matter it is fixed welding fume clarifier, still small-size portable welding fume clarifier, its flexible bellows all is shorter, and the welding area that the dust cage can cover is limited, can't satisfy the user demand of the big welding production in welding area. In addition, for the fixed and movable welding fume purifier, because the dust-collecting cover can not move along with the welding gun in the hand of the welder, when the welding gun changes a welding position, the dust-collecting cover needs to be manually pulled to the welding point to absorb the welding fume to the maximum extent, the operation is troublesome, and even if the operation is troublesome, the dust-collecting cover can not completely absorb the welding fume, and the welding fume can be inevitably diffused to influence the physical health of the welder.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a processing system is collected to welding flue gas to solve dust cage troublesome poeration among the prior art, and can not inhale the welding flue gas completely because of the dust cage, and lead to the welding flue gas diffusion, influence the healthy problem of welder.

In order to achieve the above object, the utility model provides a processing system is collected to welding flue gas adopts following technical scheme:

a welding flue gas collecting and processing system comprises a dust remover and a flue gas pipeline which is connected with the dust remover and extends along the left-right direction, wherein a plurality of pipeline connecting pipes which are communicated with the flue gas pipeline and are arranged at intervals along the left-right direction are arranged on the flue gas pipeline; the welding flue gas collecting and processing system further comprises a closed dust collecting chamber which is used for covering the outside of the part to be welded, wheels for moving the dust collecting chamber are arranged at the bottom of the dust collecting chamber, a dust collecting cover for absorbing the welding flue gas is arranged in the dust collecting chamber, an air taking pipe communicated with the dust collecting cover is further arranged on the dust collecting chamber, and the air taking pipe is used for being connected with different pipeline connecting pipes along with the movement of the dust collecting chamber.

The beneficial effects of the above technical scheme are that: in the welding fume collecting and processing system of the utility model, because the dust collecting chamber is a closed dust collecting chamber and is used for covering the outer part of the parts to be welded, meanwhile, because the bottom of the dust collecting chamber is provided with wheels for the dust collecting chamber to move, the fume pipeline is provided with a plurality of pipeline connecting pipes which are communicated with the fume pipeline and are arranged at intervals along the left and right directions, and the dust collecting chamber is internally provided with a dust collecting cover for absorbing the welding fume, the dust collecting chamber is also provided with an air taking pipe communicated with the dust collecting cover, the air taking pipe is used for connecting with different pipeline connecting pipes along with the movement of the dust collecting chamber, therefore, when welding operation is carried out, compared with the prior art, the welding fume collecting chamber can be moved to the position of any welding operation through the wheels, the adjustment of the position of the dust collecting chamber is convenient, and the dust collecting cover can be connected with the nearby pipeline connecting pipes through the air taking pipe so as to realize the connection of the dust collecting cover and the fume pipeline, carry out the collection processing of welding flue gas, can also guarantee to have shorter connecting line between dust cage and the flue gas pipeline simultaneously, in addition, through closed dust collecting chamber, can concentrate the welding flue gas that the welding produced in the dust collecting chamber, be favorable to reducing the outdiffusion of welding flue gas, staff's in the workshop healthy has been guaranteed, the in-process of welding flue gas is absorb to the dust cage in the dust collecting chamber simultaneously, because the welding flue gas is all concentrated in the dust collecting chamber, consequently need not to stimulate the dust cage with the hand, the use of dust cage has been made things convenient for.

Further, the dust chamber includes a moving frame and a sealing curtain disposed outside the moving frame.

The beneficial effects of the above technical scheme are that: the movable frame can ensure the integral strength of the dust collecting chamber, reduce the weight of the dust collecting chamber and facilitate the movement of the dust collecting chamber; through the sealing curtain, the formation of the closed space in the dust collecting chamber is facilitated, and meanwhile, the weight of the dust collecting chamber can be further reduced to a certain degree.

Furthermore, the movable frame is a door-shaped frame which is communicated from left to right, and the sealing curtains positioned on the left side and the right side of the door-shaped frame are movable sealing curtains which can be folded and unfolded, so that the door-shaped frame directly moves to the outside of the parts to be welded when the movable sealing curtains are folded.

The beneficial effects of the above technical scheme are that: the door-shaped frame is beneficial to conveniently moving the movable frame to the outside of the part to be welded along the left and right directions, namely, the dust collecting chamber can straddle the front side and the back side of the part to be welded, and the welding part of the part to be welded is conveniently positioned in the dust collecting chamber; set up movable curtain, moving the dust collecting chamber to treating when welding spare part is outside like this, can upwards pack up movable curtain to dodge and treat welding spare part, conveniently treat that welding spare part gets into in the dust collecting chamber, treat that welding spare part gets into the dust collecting chamber after, the accessible puts down movable curtain, so that forms the enclosure space in the dust collecting chamber, makes things convenient for the welding flue gas diffusion in the dust collecting chamber, is favorable to making things convenient for the absorption of welding flue gas.

Furthermore, the length of the movable frame is more than or equal to 5 meters, the width of the movable frame is more than or equal to 4 meters, and the height of the movable frame is more than or equal to 2 meters.

The beneficial effects of the above technical scheme are that: therefore, the dust collecting chamber has larger coverage area, namely, the dust collecting chamber can cover a welding area in a larger range, and the welding production of parts with large welding area and large size specification is facilitated.

Further, the sealing curtain is a flame-retardant curtain.

The beneficial effects of the above technical scheme are that: through fire-retardant curtain, can avoid the mars that produces to spatter the emergence that causes the conflagration on the sealed curtain when welding.

Further, the sealing curtain is a transparent curtain.

The beneficial effects of the above technical scheme are that: therefore, the observation of welding production in the dust collecting chamber outside the dust collecting chamber is facilitated, and meanwhile, the observation of production conditions outside the dust collecting chamber in the dust collecting chamber is also facilitated.

Furthermore, the pipeline connecting pipe is a flexible corrugated pipe with a set length, and the air taking pipe is directly connected with the pipeline connecting pipe.

The beneficial effects of the above technical scheme are that: therefore, the connection between the pipeline connecting pipe and the air taking pipe is facilitated, and meanwhile, the flexible corrugated pipe has certain extension amount, so that the extension range of the single pipeline connecting pipe can be increased, the number of the pipeline connecting pipes can be reduced, and the cost can be reduced.

Furthermore, the pipeline connecting pipe is a rigid pipe, and the air taking pipe is connected with the pipeline connecting pipe through a flexible corrugated pipe.

The beneficial effects of the above technical scheme are that: the pipeline connecting pipe is set to be a rigid pipe, so that the strength of the pipeline connecting pipe can be ensured, and the connection strength between the pipeline connecting pipe and the flue gas pipeline can also be ensured; the flexible corrugated pipe is convenient for the connection between the pipeline connecting pipe and the air taking pipe.

Furthermore, the dust hood comprises a fixed dust hood fixed on the dust collecting chamber and at least one movable dust hood communicated with the fixed dust hood, and a flexible corrugated pipe is connected between the movable dust hood and the fixed dust hood.

The beneficial effects of the above technical scheme are that: the dust hood is fixed, so that the dust hood is convenient to arrange on the dust collecting chamber and is convenient to connect with the air taking pipe; through fixed dust cage and activity dust cage, be favorable to guaranteeing the absorption effect of dust cage to the welding flue gas, connect activity dust cage and fixed dust cage through flexible bellows simultaneously, not only made things convenient for being connected between activity dust cage and the fixed dust cage, and flexible bellows is also convenient for draw materials moreover, has made things convenient for the manufacturing of dust collecting chamber, in addition, also can change the position of activity dust cage a little through flexible bellows, make the mounted position requirement of activity dust cage not high, be favorable to making things convenient for the installation of activity dust cage.

Furthermore, a valve is arranged on the air taking pipe.

The beneficial effects of the above technical scheme are that: the valve is arranged, so that the closing and the conduction of the air taking pipe are controlled conveniently, and the connection between the air taking pipe and the pipeline connecting pipe is controlled conveniently.

Drawings

FIG. 1 is a schematic view of a welding fume collection and treatment system of the present invention;

FIG. 2 is a schematic diagram of the arrangement of flue gas pipes in the welding flue gas collecting and processing system of the present invention in a workshop;

FIG. 3 is a perspective view of a movable frame in the welding fume collecting and treating system of the present invention;

FIG. 4 is a rear view of the moving frame of the welding fume collecting and processing system of the present invention;

fig. 5 is a right side view of the moving frame in the welding fume collecting and processing system of the present invention.

In the figure: 10. a dust remover; 20. an induced draft fan; 21. a drive motor; 30. a chimney; 40. a flue gas duct; 50. a column; 60. a pipe connecting pipe; 70. a dust collecting chamber; 71. a moving frame; 72. a sealing curtain; 80. a wheel; 90. fixing a dust collection cover; 100. a movable dust collection cover.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more clear, the present invention is further described in detail with reference to the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not to be construed as limiting the invention, i.e., the described embodiments are merely illustrative of some, but not all, of the embodiments of the invention. The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the accompanying drawings, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. Based on the embodiment of the present invention, all other embodiments obtained by the person skilled in the art without creative work belong to the protection scope of the present invention.

It should be noted that, in the detailed description of the present invention, terms such as "first" and "second" may be used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between the entities or operations. Also, terms such as "comprises," "comprising," or any other variation thereof, which may be present, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, the appearances of the phrase "comprising an … …" or similar limitation may be present without necessarily excluding the presence of additional identical elements in the process, method, article, or apparatus that comprises the same elements.

In the description of the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" when they are used are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; either directly or indirectly through intervening media, or may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood by those skilled in the art from the specific situation.

In the description of the present invention, unless otherwise explicitly specified or limited, the term "provided" may be used in a broad sense, for example, the object of "provided" may be a part of the body, or may be arranged separately from the body and connected to the body, and the connection may be a detachable connection or a non-detachable connection. The specific meaning of the above terms in the present invention can be understood by those skilled in the art from the specific situation.

The present invention will be described in further detail with reference to examples.

The utility model discloses well welding flue gas collecting and processing system's embodiment 1:

as shown in fig. 1, the welding fume collecting and processing system includes a fume duct 40 with an axis extending in the left-right direction, as shown in fig. 2, in this embodiment, three fume ducts 40 arranged in parallel are provided in the workshop, in other embodiments, one, two, four or more fume ducts 40 may be provided in the workshop according to the use requirement, and each fume duct 40 is supported and fixed by a column 50 in the workshop.

As shown in fig. 1 and 2, the welding fume collecting and processing system further includes a dust remover 10 located outside the workshop, and an induced draft fan 20 communicated with the dust remover 10. The number of the dust collectors 10 is one, the dust collectors 10 are respectively communicated with the flue gas pipelines 40, the induced draft fan 20 is in transmission connection with the driving motor 21, namely the induced draft fan 20 can be driven to act through the driving motor 21, so that negative pressure can be generated in the dust collectors 10 and the flue gas pipelines 40 through the induced draft fan 20, and welding flue gas in the flue gas pipelines 40 is sucked into the dust collectors 10 for purification treatment. In addition, the induced draft fan 20 is further provided with a chimney 30 communicated with the atmosphere, so that the flue gas purified by the dust remover 10 can be discharged to the atmospheric environment through the induced draft fan 20 and the chimney 30.

As shown in fig. 1 and fig. 2, each flue gas duct 40 is provided with four duct connection pipes 60 which are communicated with the corresponding flue gas duct 40 and are arranged at intervals in the left-right direction, and in this embodiment, each duct connection pipe 60 is a flexible corrugated pipe with a set length. In other embodiments, two, three, five or more flue gas pipes may be further disposed on one flue gas pipe, and the number of the specific pipe connection pipes needs to be determined according to the size of the actual welding area.

As shown in fig. 1, the welding fume collecting and processing system further comprises a dust collecting chamber 70 for covering the outside of the parts to be welded, as shown in fig. 3, 4 and 5, the dust collecting chamber 70 comprises a moving frame 71 and a sealing curtain 72 disposed outside the moving frame 71. The length of the moving frame 71 is 8 meters, the width is 6 meters, the height is 2.7 meters, and the moving frame 71 is a door-shaped frame which penetrates left and right, so that the dust collecting chamber 70 can be bestrided on the outer part of the parts to be welded through the moving frame 71, and the parts to be welded of the parts to be welded are positioned in the dust collecting chamber 70. In addition, in order to facilitate the movement of the dust collecting chamber 70, as shown in fig. 1, 4 and 5, wheels 80 for moving the dust collecting chamber 70 are provided at the bottom of the moving frame 71, specifically, four wheels 80 are provided at the front and rear sides of the moving frame 71, respectively, and in this embodiment, the dust collecting chamber 70 can be moved by being pushed manually, and in other embodiments, a motor in transmission connection with the wheels 80 can be further provided on the moving frame 71, so as to drive the wheels 80 to rotate by the motor, and further drive the dust collecting chamber 70 to move.

The sealing curtains 72 positioned on the left side, the right side, the front side and the rear side of the moving frame 71 are retractable movable sealing curtains 72, so that when the sealing curtains 72 on the left side and the right side of the moving frame 71 are retracted, the moving frame 71 can be directly moved to the outside of the part to be welded, and the part to be welded of the part to be welded can conveniently enter the dust collecting chamber 70. When the sealing curtains 72 on the left and right sides and the front and rear sides of the moving frame 71 are all lowered, a closed space is formed in the dust collecting chamber 70 to prevent the welding fume in the dust collecting chamber 70 from being diffused outward. In addition, each sealing curtain 72 is a transparent flame-retardant curtain, namely, the sealing curtain is a transparent curtain and a flame-retardant curtain, so that not only can fire caused by sparks generated in welding splashing on the sealing curtain 72 be avoided, but also the observation of welding production in the dust collecting chamber 70 from the outside of the dust collecting chamber 70 and the observation of production conditions outside the dust collecting chamber 70 in the dust collecting chamber 70 are facilitated.

As shown in fig. 1, a dust collection cover for sucking welding fume is disposed in the dust collection chamber 70, and the dust collection cover includes a fixed dust collection cover 90 fixed on the movable frame 71 and two movable dust collection covers 100 communicated with the fixed dust collection cover 90. Wherein, the two movable dust collecting hoods 100 are respectively arranged at the left and right sides of the fixed dust collecting hood 90, and the two movable dust collecting hoods 100 are connected with the fixed dust collecting hood 90 through flexible corrugated pipes. The fixed dust hood 90 and the two movable dust hoods 100 form a dust hood group, and the specific number of the dust hood groups in a dust chamber can be determined according to the volume of the dust chamber and the specific negative pressure value generated by the induced draft fan.

The movable frame 71 is further provided with an air intake pipe communicated with the fixed dust hood 90, the air intake pipe is used for being connected with different pipeline connecting pipes 60 along with the movement of the dust collecting chamber 70, and the air intake pipe is directly connected with each pipeline connecting pipe 60, so that after the air intake pipe is connected with one of the pipeline connecting pipes 60, each dust hood can absorb the welding smoke in the dust collecting chamber under the action of negative pressure in the smoke pipeline. The air taking pipe is provided with a valve, so that after the air taking pipe is directly connected with the pipeline connecting pipe 60, the on-off of the connection between the air taking pipe and the pipeline connecting pipe 60 can be controlled through the valve.

When the welding smoke collecting and processing system in the utility model is used for welding operation, compared with the prior art, the dust collecting chamber can be moved to any position of welding operation through the wheels, thereby facilitating the adjustment of the position of the dust collecting chamber, and the dust collecting cover can be connected with the nearby pipeline connecting pipe through the air taking pipe, thereby realizing the connection of the dust collecting cover and the smoke pipeline, and carrying out the collection processing of the welding smoke, meanwhile, a shorter connecting pipeline can be ensured between the dust collecting cover and the smoke pipeline, in addition, the welding smoke generated by welding can be concentrated in the dust collecting chamber through the closed dust collecting chamber, thereby being beneficial to reducing the outward diffusion of the welding smoke, ensuring the health of workers in a workshop, simultaneously, in the process of absorbing the welding smoke by the dust collecting cover in the dust collecting chamber, because the welding smoke is concentrated in the dust collecting chamber, the dust collecting cover does not need to be pulled by hands, the use of the dust hood is convenient. In addition, the dust collecting chamber has a larger covering area, so that the dust collecting chamber can cover a larger welding area, and the application of the welding smoke collecting and processing system in the welding production of parts with large welding areas and large size specifications is facilitated.

In other embodiments of the welding fume collecting and processing system, the air taking pipe is not provided with a valve, and in such a case, the connection between the air taking pipe and the pipeline connecting pipe cannot be controlled to be switched on or off.

In other embodiments of the welding fume collection and treatment system, the movable dust hood is not connected to the fixed dust hood by a flexible bellows, but by a rigid tube, in which case only the fixed dust hood is installed in the dust chamber.

In other embodiments of the welding fume collecting and processing system, the number of the movable dust collecting covers is not two, but one, and in other embodiments, the number of the movable dust collecting covers can be three, four, etc., as long as the suction effect of the welding fume in the dust collecting chamber can be ensured.

In other embodiments of the welding fume collecting and processing system, the pipeline connecting pipe may not be a flexible corrugated pipe with a set length, but is a rigid pipe, and the air taking pipe is connected with the pipeline connecting pipe through the flexible corrugated pipe.

In other embodiments of the welding fume collection and treatment system, the sealing curtain is not a transparent curtain, in which case the welding production within the dust chamber cannot be observed directly through the sealing curtain.

In other embodiments of the welding fume collecting and processing system, the sealing curtain is not a flame-retardant curtain, i.e. the sealing curtain has no flame-retardant function, and the sealing curtain is a high-temperature-resistant sealing curtain.

In other embodiments of the welding fume collection and treatment system, the moving frame has a length of 5 meters, a width of 4 meters, and a height of 2 meters, and in other embodiments, the moving frame may also have dimensions of 7 meters, a width of 5.5 meters, and a height of 2.5 meters.

In other embodiments of the welding fume collection and treatment system, the movable frame is not a door-shaped frame, i.e. the movable frame cannot straddle the exterior of the parts to be welded, in which case, when the parts to be welded enter the dust collection chamber, the parts to be welded can be directly lifted into the dust collection chamber or the movable frame can be integrally lifted and placed on the exterior of the parts to be welded.

In other embodiments of the welding fume collection and treatment system, the exterior of the moving frame may be provided with no sealing curtain, but with a baffle, and the side of the dust chamber may be provided with a double door, in which case the double door may be opened to allow the parts to be welded to enter the dust chamber.

The above description is only for the preferred embodiment of the present invention, and the present invention is not limited thereto, the protection scope of the present invention is defined by the claims, and all structural changes equivalent to the contents of the description and drawings of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A welding fume collecting and processing system comprises a dust remover (10) and a fume pipeline (40) which is connected with the dust remover (10) and extends along the left-right direction, and is characterized in that a plurality of pipeline connecting pipes (60) which are communicated with the fume pipeline (40) and are arranged at intervals along the left-right direction are arranged on the fume pipeline (40); the welding flue gas collecting and processing system further comprises a closed dust collecting chamber (70) used for being covered outside the parts to be welded, wheels (80) for the dust collecting chamber (70) to move are arranged at the bottom of the dust collecting chamber (70), a dust collecting cover used for sucking welding flue gas is arranged in the dust collecting chamber (70), an air taking pipe communicated with the dust collecting cover is further arranged on the dust collecting chamber (70), and the air taking pipe is used for being connected with different pipeline connecting pipes (60) along with the movement of the dust collecting chamber (70).

2. The welding fume collection processing system according to claim 1, wherein the dust collection chamber (70) comprises a moving frame (71) and a sealing curtain (72) disposed outside the moving frame (71).

3. The welding fume collecting and processing system according to claim 2, characterized in that the moving frame (71) is a door-shaped frame which is through from left to right, and the sealing curtains (72) positioned at the left and right sides of the door-shaped frame are movable sealing curtains which can be folded and unfolded, so that the door-shaped frame directly moves to the outside of the parts to be welded when the movable sealing curtains are folded.

4. The welding fume collection processing system according to claim 2 or 3, characterized in that the length of the moving frame (71) is greater than or equal to 5 meters, the width is greater than or equal to 4 meters, and the height is greater than or equal to 2 meters.

5. The welding fume collection and treatment system according to claim 2 or 3, wherein the sealing curtain (72) is a flame retardant curtain.

6. The welding fume collection and treatment system according to claim 2 or 3, wherein the sealing curtain (72) is a transparent curtain.

7. The welding fume collecting and processing system according to any one of claims 1 to 3, wherein the duct connecting pipe (60) is a flexible corrugated pipe with a set length, and the air intake pipe is directly connected with the duct connecting pipe (60).

8. The welding fume collecting and processing system according to any one of claims 1 to 3, wherein the pipeline connecting pipe (60) is a rigid pipe, and the air taking pipe is connected with the pipeline connecting pipe (60) through a flexible corrugated pipe.

9. The welding fume collecting and processing system according to any one of claims 1 to 3, wherein the dust hood comprises a fixed dust hood (90) fixed on the dust chamber (70) and at least one movable dust hood (100) communicated with the fixed dust hood (90), and a flexible corrugated pipe is connected between the movable dust hood (100) and the fixed dust hood (90).

10. The welding fume collecting and processing system according to any one of claims 1 to 3, wherein the air intake pipe is provided with a valve.

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