CN211692333U - Stepping rock drill with drill withdrawal device - Google Patents

Abstract

The utility model discloses a stepping rock drill with a drill withdrawal device, which comprises a rock drilling host, a guide rail and a drill bearing sliding table, wherein a first locking device is arranged between the drill bearing sliding table and the guide rail; the drill bearing sliding table is also provided with a drill withdrawing device; the drill withdrawal device comprises a locking slide block and a driving mechanism with reciprocating output motion, wherein the driving mechanism is connected between a drill bearing sliding table and the locking slide block, and the locking slide block is only longitudinally movably arranged on the drill bearing sliding table; the first locking device is arranged between the locking slide block and the guide rail. The beneficial effects of the utility model are that, withdraw from the drill bit when can conveniently realizing the card and boring to can be according to footage adjustment rig guide rail length, and rig front end firm in support, accomplish the drilling after, the rig wholly withdraws from smoothly. The tunnel construction system has complete functions, is beneficial to realizing automatic control, provides guarantee for the mechanical operation of tunnel construction, can effectively reduce the over excavation of the tunnel, improves the construction efficiency and reduces the construction cost.

Description

Stepping rock drill with drill withdrawal device

Technical Field

The utility model relates to a guide rail structure, especially a step-by-step rock drill with move back brill device.

Background

The step-by-step rock drill is a mechanical rock drilling equipment for replacing manual rock drilling in tunnel construction, and is formed by arranging a manual shouldering type pneumatic rock drill on a guide rail. The pneumatic drilling machine comprises a drilling machine bearing sliding table and a pneumatic leg bearing sliding table, wherein the drilling machine bearing sliding table can move on a guide rail; the other end of the air leg bearing sliding table is connected to the air leg bearing sliding table, a locking device is arranged between each of the two sliding tables and the guide rail, and when the drilling machine bearing sliding table is locked, the air leg bearing sliding table correspondingly moves forwards or backwards along the drilling direction along with the retraction or extension of the air leg; when the air leg bearing sliding table is locked, the drilling machine and the drilling machine bearing sliding table correspondingly drill and retreat along with the extension or retraction of the air leg; thus, the stepping rock drilling is formed, and the automation can be realized through a simple industrial control technology. Compared with large-scale special large-scale rock drilling equipment, the drilling machine has the advantages of low manufacturing cost, low maintenance and use cost, and is particularly suitable for tunnel construction of domestic construction teams. However, in the actual construction process, the drill bit is inevitably stuck due to factors such as the change of the geological structure of the tunnel, and although the air leg is matched with the tunnel to have the function of withdrawing the drill bit, the air leg is limited by the structure and the function of the air leg due to the large drill sticking force, so that the drill bit cannot be withdrawn smoothly. For this reason, a device is required on the drilling machine, which is dedicated to the withdrawal of the drill bit during the jamming of the drill.

Disclosure of Invention

The utility model aims at providing a stepping rock drill with move back the brill device to the not enough that can not withdraw from smoothly behind the marching type rock drill machine sticking of prior art to when the sticking is bored, can be smooth withdraw from the drill bit.

In order to achieve the above purpose, the present invention adopts the following technical solution.

A stepping rock drill with a drill withdrawal device comprises a rock drilling host, a guide rail and a drill bearing sliding table, wherein a first locking device is arranged between the drill bearing sliding table and the guide rail; the drill bearing sliding table is also provided with a drill withdrawing device; the drill withdrawal device comprises a locking sliding block and a driving mechanism with reciprocating movement output motion, wherein the driving mechanism is connected between the drill bearing sliding table and the locking sliding block, and the locking sliding block is only longitudinally movably arranged on the drill bearing sliding table; the first locking device is arranged between the locking slide block and the guide rail.

Adopt aforementioned technical scheme the utility model discloses, set up between rig load-bearing platform and guide rail and move back the brill device, should move back the brill device and establish between slider and guide rail through the first locking device who bears the rig slip table, the slider can be mobilizable setting for rig load-bearing guide rail, when slider and guide rail pass through first locking device locking, but the rig bears the slip table longitudinal movement under the actuating mechanism effect, thereby when the card bores the back and need move back the brill, make the rig bear the slip table and retreat, reach and move back the brill purpose. And the locking and unlocking of the first locking device and the alternative actions of extension and retraction of the driving mechanism can be realized according to the drill clamping condition, and the drill withdrawal process with the set distance or length is completed. The driving mechanism can adopt a hydraulic cylinder, a screw nut pair driving structure or a crank slider driving structure and the like. The automatic drill bit withdrawing device is simple in structure, strong in drill withdrawing capability and reliable in function, and automatic control is conveniently achieved, for example, after the drill bit is determined to be stuck or stuck in a manual observation or torque detection mode, the drill withdrawing action of the drill bit is implemented through wire control, remote control or remote control.

Preferably, the driving mechanism is constituted by an oil cylinder. The oil cylinder can be connected to one of the bearing sliding table or the locking sliding block of the drilling machine through the cylinder body, and the other oil cylinder is connected with the far end of the piston rod of the oil cylinder. The characteristics of high pressure and large thrust of the oil cylinder are utilized, so that the volume of the driving mechanism is reduced, the weight is reduced and the whole machine layout is facilitated under the condition that the sufficient drill withdrawal power is ensured; the connection between the oil cylinder and the bearing sliding table and the locking sliding block of the drilling machine is usually in a hinged mode so as to ensure flexible operation. When the locking slide block is arranged in front of the oil cylinder in the drilling direction, the locking slide block is locked with the guide rail through the first locking device under the retraction state of the oil cylinder piston, and the oil cylinder piston rod extends out to implement drill withdrawal; when the locking slide block is arranged behind the oil cylinder in the drilling direction, the locking slide block is locked with the guide rail through the first locking device under the state that the piston of the oil cylinder extends out, and the piston rod of the oil cylinder retracts to implement the drill withdrawal.

Further preferably, two opposite guide grooves are formed in the drill bearing sliding table through a protruding block, the locking sliding block is located between the two guide grooves, and guide portions in sliding fit with the guide grooves are formed in two sides of the locking sliding block. The guide rail pair structure with a simple structure is formed by matching the guide groove and the guide part, so that the locking slide block is ensured to move in a determined direction, and the operation is flexible.

Preferably, the first locking device comprises a first locking cylinder and a plurality of locking holes longitudinally distributed on the guide rail; a piston rod of the first locking cylinder is integrally formed or fixedly connected with a lock pin which is matched with the locking hole to form a bolt type locking structure; and a long hole for the lock pin to move horizontally along the guide groove is formed on the drill bearing sliding table. The locking and unlocking are formed by the telescopic power transmission of the piston rod of the locking cylinder, so that the structure is simplified, the reliability is improved, and the cost is reduced.

Preferably, the front end of the guide rail is provided with a front end support sleeve for supporting the drill rod, the middle section of the guide rail is provided with an intermediate support sleeve, and the intermediate support sleeve is arranged on the jacking device. The drill rod utilizing the slender members has the characteristic of certain deflection, and is jacked upwards in the middle of the drill rod to form an arch shape, so that when peripheral holes are drilled, the drill bit forms a certain back-bending radian to drill into a rock body, the serious over-excavation caused by a linear drilling mode is avoided, the over-excavation amount is effectively reduced, and the tunneling efficiency is improved. Usually, after the drill bit drills to a certain depth, such as 1-2 meters, the jacking state is released, and a drill hole forming a certain radian forms a guide hole for the drill bit to drill forwards, so that the same drilling mode as the drilling mode for reducing overbreak measures in the manual drilling process is formed. Wherein, jacking system adopts cylinder, pneumatic cylinder etc. as the power supply to reduce occupation space, convenient overall arrangement. Of course, other driving structures for linear movement, such as a screw-nut pair driving structure, a rack-and-pinion driving structure, or a slider-and-crank driving structure, may be adopted under the condition of space allowance.

Preferably, the jacking device comprises a jacking base and a lifting block, the jacking base is arranged on the guide rail and is fixedly connected with a jacking cylinder, the far end of a piston rod of the jacking cylinder is connected with a pushing block, and the front end of the pushing block is provided with a pushing inclined plane; the lifting block can only be vertically matched in the jacking cylinder in a lifting way, the jacking cylinder is fixed on the jacking base, the lower end of the lifting block is provided with a roller, and the roller is in rolling connection with the jacking inclined plane; the middle supporting sleeve is fixedly connected to the upper end of the lifting block. The jacking cylinder is arranged to be in a layout longitudinally parallel to the drill rod through the jacking inclined surface, so that the length space is fully utilized, the space occupied by the height space is reduced, and the layout rationality is improved.

Preferably, the guide rail is formed by a base section and an extension section into a structure with variable length; an extension positioning structure and an extension locking mechanism are arranged between the basic section and the extension section; the foundation section and the extension section are connected through an inclined joint surface; the joint surface is gradually inclined outwards from top to bottom on the base section; the lengthening positioning structure is used for preventing the base section and the lengthening section from being staggered left and right and from being staggered up and down. So that guide rail length can increase and decrease the adjustment according to the construction footage difference, broadens application range to through location structure and extension locking structure, ensure that the whole rigidity of guide rail after the extension is good, intensity is high, connect reliably, safe in utilization, and all do not misplace about and from top to bottom, ensure that the slip table removes in joint portion on the guide rail in a flexible way.

Further preferably, the lengthening locking mechanism is an eccentric locking structure. The characteristic that an eccentric locking structure is convenient to form a locking dead point is utilized, the locking reliability is ensured, and the operation is convenient.

Preferably, the lower part of the front end of the guide rail is fixedly connected with a guide rail fixing device for supporting the guide rail through a rock body. The front end fixing device is used for supporting the overhanging part of the guide rail, so that the supporting strength and rigidity of the guide rail are improved, and the drilling speed and the construction efficiency are further improved. Wherein, the guide rail fixing device utilizes the member that can insert the rock mass to provide the support, can set up different structures according to the characteristic of tunnel rock mass. For soft rock, the front end of the guide rail can be provided with a drill steel with a conical tip at the front end, and the drill steel keeps the firmness of inserting into the rock through a jacking spring; a drilling machine can also be fixedly arranged at the front end of the guide rail, and after the drill rod is drilled into the guide rail, the drill rod is utilized to form the supporting member.

Preferably, the device also comprises an air leg, and an electric switch valve and an electric flow regulating valve which are arranged in parallel are arranged on an air inlet pipeline or an exhaust pipeline of the air leg. The electric flow control valve is used for controlling air inflow in the process of kicking the leg by the gas leg in drilling to realize the adjustment of the drilling speed, and when the gas leg is required to be rapidly stretched, the electric switch valve is used for independently ventilating or ventilating with the electric flow control valve to meet the requirement of large-flow air inflow and exhaust.

The beneficial effects of the utility model are that, withdraw from the drill bit when can conveniently realizing the card and boring to can be according to footage adjustment rig guide rail length, and rig front end firm in support, accomplish the drilling after, the rig wholly withdraws from smoothly. The tunnel construction system has complete functions, is beneficial to realizing automatic control, provides guarantee for the mechanical operation of tunnel construction, can effectively reduce the over excavation of the tunnel, improves the construction efficiency and reduces the construction cost.

Drawings

Fig. 1 is a schematic perspective view of the structure of the present invention.

Fig. 2 is a schematic view of a part of the structure of the jacking device of the present invention.

Fig. 3 is a schematic front view of the guide rail structure of the present invention.

Fig. 4 is an enlarged view of a portion a in fig. 3 according to the present invention.

Figure 5 is a top view of the present invention as shown in figure 4 wherein the elongated locking mechanism is in a locked position.

Fig. 6 is a schematic diagram of a middle gas circuit of the present invention.

Detailed Description

The present invention will be further described with reference to the accompanying drawings, which are not intended to limit the scope of the embodiments described herein.

Referring to fig. 1, 2, 3, 4, 5 and 6, a stepping rock drill with a drill withdrawal device comprises a rock drilling main machine 1, a guide rail 2, a drill bearing sliding table 3, an air leg 14 and an air leg bearing sliding table 18, wherein a first locking device is arranged between the drill bearing sliding table 3 and the guide rail 2; the drill bearing sliding table 3 is also provided with a drill withdrawing device; the drill withdrawal device comprises a locking slide block 5 and a driving mechanism 6 with reciprocating movement output motion, wherein the driving mechanism 6 is connected between the drill bearing sliding table 3 and the locking slide block 5, and the locking slide block 5 is only longitudinally movably arranged on the drill bearing sliding table 3; the first locking device is arranged between the locking slide block 5 and the guide rail 2; the air leg 14 is connected between the drill rig bearing sliding table 3 and the air leg bearing sliding table 18; a second locking device is arranged between the air leg bearing sliding table 18 and the guide rail 2.

Wherein, the driving mechanism 6 is composed of an oil cylinder. Wherein, the oil cylinder is connected on the drill bearing sliding table 3 through the cylinder body thereof, and the locking slide block 5 is connected with the far end of the piston rod of the oil cylinder. Two opposite guide grooves are formed in the drill bearing sliding table 3 through bumps, the locking sliding block 5 is located between the two guide grooves, and guide portions in sliding fit with the guide grooves are formed in two sides of the locking sliding block 5. The first locking device comprises a first locking cylinder 4 and a plurality of locking holes which are longitudinally distributed on the guide rail 2; a lock pin which is integrally formed or fixedly connected with a piston rod of the first locking cylinder 4 is matched with the locking hole to form a bolt type locking structure; and a long hole for the lock pin to move horizontally along the guide groove is formed on the drill bearing sliding table 3. The second locking means is also formed by a plurality of locking holes distributed longitudinally on the guide rail 2 and a second locking spigot on the piston rod of a second locking cylinder 19.

The front end of the guide rail 2 is provided with a front end supporting sleeve 7 for supporting a drill rod, the middle section of the guide rail 2 is provided with an intermediate supporting sleeve 8, and the intermediate supporting sleeve 8 is arranged on the jacking device. The jacking device comprises a jacking base and a jacking block 11, wherein the jacking base 39 is adjustably arranged on the guide rail 2 and is fixedly connected with a jacking cylinder 9, the far end of a piston rod of the jacking cylinder 9 is connected with a pushing block 10, and the front end of the pushing block 10 is provided with a jacking inclined plane; the lifting block 11 can only be vertically matched in the jacking cylinder 12 in a lifting way, the jacking cylinder 12 is fixed on the jacking base, the lower end of the lifting block 11 is provided with a roller 13, and the roller 13 is in rolling connection with the jacking inclined plane; the middle supporting sleeve 8 is fixedly connected to the upper end of the lifting block 11.

The guide rail 2 is formed into a structure with variable length by a base section 21 and an extension section 22; an extension positioning structure and an extension locking mechanism are arranged between the basic section 21 and the extension section 22; the foundation section 21 and the extension section 22 are connected through an inclined joint surface; the bonding surface is gradually inclined outwards from top to bottom on the base section 21; the extension positioning structure is used for preventing the base section 21 and the extension section 22 from being staggered left and right and up and down. The guide rail 2 comprises a guide rail main body and a track, wherein the track is made of a circular tube, and the guide rail main body is made of a square tube or a rectangular tube; the lengthening positioning structure comprises a positioning column 24 matched with a circular tube inner hole of the track, one part of the positioning column 24 is inserted into the circular tube track tube hole of the basic section 21, and the other part of the positioning column is inserted into the circular tube track tube hole of the lengthening section 22. The square pipe or the rectangular pipe can be a rolled or drawn section bar, and can also be formed by bending a steel plate and then welding; the guide rail main body is formed by combining two square tube welding machines in the height direction; the upper ends of two sides of the square steel pipe above are respectively welded with a round pipe, the round pipes form the track, two sides of the lower end of the square steel pipe below are respectively welded with a round pipe, a square pipe or a tube, flat steel or angle iron, and the round pipe, the square pipe or the tube, the flat steel or the angle iron below are used for installing and fixing the guide rail.

The guide rail main body is provided with two parallel rails; and the positioning columns 24 are arranged in the pipe holes of the joint parts of the two circular pipe tracks of the basic section 21 and the extension section 22. The base section 21 and the extension section 22 are connected through two connecting plates 25, the joint surfaces of the two connecting plates 25 form the joint surfaces of the base section 21 and the extension section 22, and the two connecting plates 25 are respectively welded and fixed on the guide rail main bodies of the base section 21 and the extension section 22. The connecting plate 25 is welded on the lower square tube, the end part of the upper square tube is welded with an end plate, and the end plate is welded with a positioning tube; the positioning pipes on the two end plates are inserted with a third positioning column 23, and the three positioning columns are distributed on three corners of the isosceles triangle.

The lengthening locking mechanism is an eccentric locking structure. The lengthening locking mechanism comprises a hook 26 and a ring buckle 27, and the hook 26 is fixedly arranged on the base section 21; the ring buckle 27 is hinged to the handle 28, and the handle 28 is hinged to the extension section 22. The ring buckle 27 is movably arranged on a ring buckle seat 29, the ring buckle seat 29 is hinged on the handle 28, and a loading spring 30 is arranged between the ring buckle seat 29 and the ring buckle 27. Wherein, one end of the ring buckle 27 is welded with a connecting rod 27a, and the free end of the connecting rod 27a is welded with a guide block 27 b; one end of the ring buckle seat 29 is provided with a rod-shaped structure, the ring buckle seat 29 is hinged with the handle 28 through one end of the rod-shaped structure, the other end of the ring buckle seat 29 is in a frame-shaped structure, the connecting rod 27a extends into the frame from one end of the frame-shaped structure, the frame walls on two sides of the frame-shaped structure are provided with sliding grooves 29a, and the guide blocks 27b are in sliding fit in the sliding grooves 29 a; the loading spring 30 abuts against the guide block 27b at one end and against the inner wall of one end of the frame-shaped structure at the other end. The hinged seat of the handle 28 is formed by two independent lugs 28a, and the connecting shaft is formed by two half shafts 8 b; in the locked state, the connection line between the hinge center of the buckle seat 29 and the handle 28 and the hinge center of the handle 28 and the connecting section 22 is coincident with the axis of the connecting rod 27 a. The hook 26 can also be arranged on the extension section 22, and the handle 28 is hinged on the base section 21.

In addition, a guide rail fixing device 31 for supporting the guide rail 2 through a rock body is fixedly connected to the lower portion of the front end of the guide rail 2. The front end fixing device forms a support for the overhanging part of the guide rail 2, and the support strength and rigidity of the guide rail are improved. Wherein the rail fixing device 31 provides support by means of a rock mass insertable member, different configurations can be provided according to the characteristics of the tunnel rock mass. For soft rock, the front end of the guide rail can be provided with a drill steel with a conical tip at the front end, and the drill steel keeps the firmness of inserting into the rock through a jacking spring; a drilling machine can also be fixedly arranged at the front end of the guide rail, and after the drill rod is drilled into the guide rail, the drill rod is utilized to form the supporting member.

When the air leg 14 pushes the rock drilling host 1 to drill, the air inlet and outlet pipelines of the air leg 14 are respectively composed of an air inlet pipeline 15 and an air outlet pipeline 34, and the air inlet pipeline 15 is provided with an electric switch valve 16 and an electric flow regulating valve 17 which are arranged in parallel. The rock drilling host 1 is connected with a drilling air supply pipe 32 and a slag blowing air supply pipe 33 through a rear cover of a drilling machine, and the drilling air supply pipe 32 and the slag blowing air supply pipe 33 are connected with the air supply main pipeline through electric control valves; the air inlet pipeline 15 and the exhaust pipeline 34 are connected to the electromagnetic directional valve 35, the air inlet of the electromagnetic directional valve 35 is connected with the air supply main pipe, and the air outlet of the electromagnetic directional valve 35 is communicated with the atmospheric environment.

The electric switch valve 16 is connected to the air inlet pipeline 15, the electric flow regulating valve 17 is connected to the air inlet bypass, the bypass is connected in parallel with the air inlet pipeline 15, and the pipe diameter of the bypass is smaller than that of the air inlet pipeline 15. The electric switch valve 16 is of a normally closed structure; the electromagnetic directional valve 35 is a three-position five-way valve with a middle sealing structure; the electric control valves for controlling the drilling gas supply pipe 32 and the slag blowing gas supply pipe 33 are composed of a first electromagnetic valve 36 and a second electromagnetic valve 37, and both the first electromagnetic valve 36 and the second electromagnetic valve 37 are switch valves; an oil pot 38 is also arranged on the main gas supply pipeline; the bore hole air supply pipe 32 has a larger pipe diameter than the slag blowing air supply pipe 33.

In this embodiment, the electromagnetic directional valve 35 may also adopt a two-position five-way valve instead of a three-position five-way valve. Furthermore, the electric on-off valve 16 and the electric flow rate control valve 17 may be connected in parallel to the exhaust line 34 of the gas leg 14.

In this embodiment, the front support sleeve 7 and the middle support sleeve 8 both comprise a bushing and a bushing seat, the bushing can freely rotate relative to the bushing seat, and the bushing seat of the front support sleeve 7 is fixedly connected with the front end of the guide rail 2 through a front support; the bushing seat of the middle support sleeve 8 is fixedly connected with the upper end of the lifting block 11.

The basic principles and the main features of the invention and the advantages of the invention have been shown and described above. It will be understood by those skilled in the art that the present invention is not limited to the above embodiments, and that the foregoing embodiments and descriptions are provided only to illustrate the principles of the present invention without departing from the spirit and scope of the present invention. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims (10)

1. A stepping rock drill with a drill withdrawal device comprises a rock drilling host (1), a guide rail (2) and a drill bearing sliding table (3), wherein a first locking device is arranged between the drill bearing sliding table (3) and the guide rail (2); the drilling machine is characterized in that a drill withdrawal device is further arranged on the drilling machine bearing sliding table (3); the drill withdrawal device comprises a locking sliding block (5) and a driving mechanism (6) with reciprocating movement output motion, wherein the driving mechanism (6) is connected between the drill bearing sliding table (3) and the locking sliding block (5), and the locking sliding block (5) is only longitudinally movably arranged on the drill bearing sliding table (3); the first locking device is arranged between the locking slide block (5) and the guide rail (2).

2. Stepping rock drill with an extractor device according to claim 1, characterized in that the driving mechanism (6) is constituted by a cylinder.

3. The stepping rock drill with the drill withdrawal device according to claim 2, characterized in that the drill carrying slide (3) is provided with two opposite guide grooves through a projection, the locking slide (5) is located between the two guide grooves, and guide portions which are in sliding fit with the guide grooves are formed on both sides of the locking slide (5).

4. Stepping rock drill with backdrilling device according to claim 1, characterized in that the first locking device comprises a first locking cylinder (4) and a plurality of locking holes distributed longitudinally on the guide rail (2); a piston rod of the first locking cylinder (4) is integrally formed or fixedly connected with a lock pin which is matched with the locking hole to form a bolt type locking structure; and a long hole for the lock pin to move horizontally along the guide groove is formed on the drill bearing sliding table (3).

5. The stepping rock drill with the drill withdrawal device according to any one of claims 1 to 4, characterized in that the front end of the guide rail (2) is provided with a front end support sleeve (7) for supporting a drill rod, the middle section of the guide rail (2) is provided with an intermediate support sleeve (8), and the intermediate support sleeve (8) is arranged on the jacking device.

6. The stepping rock drill with the drill withdrawal device according to claim 5, characterized in that the jacking device comprises a jacking base and a lifting block (11), the jacking base is arranged on the guide rail (2) and is fixedly connected with a jacking cylinder (9), the far end of a piston rod of the jacking cylinder (9) is connected with a push block (10), and the front end of the push block (10) is provided with a jacking inclined surface; the lifting block (11) can only be vertically matched in the jacking cylinder (12) in a lifting way, the jacking cylinder (12) is fixed on the jacking base, the lower end of the lifting block (11) is provided with a roller (13), and the roller (13) is in rolling connection with the jacking inclined plane; the middle supporting sleeve (8) is fixedly connected to the upper end of the lifting block (11).

7. Stepping rock drill with a backdrilling device according to any one of claims 1 to 4, characterized in that the guide rail (2) is formed of a base section (21) and an extension section (22) with a variable length; an extension positioning structure and an extension locking mechanism are arranged between the basic section (21) and the extension section (22); the foundation section (21) and the extension section (22) are connected through an inclined joint surface; the joint surface is gradually inclined outwards from top to bottom on the base section (21); the lengthening positioning structure is used for preventing the base section (21) and the lengthening section (22) from being staggered left and right and up and down.

8. Stepping rock drill with backdrilling device according to claim 7, characterized in that the lengthening locking mechanism is an eccentric locking structure.

9. The stepping rock drill with the drill withdrawal device according to any one of claims 1 to 4, characterized in that a guide rail fixing device for supporting the guide rail (2) through a rock body is fixedly connected to the lower portion of the front end of the guide rail (2).

10. The stepping rock drill with the drill withdrawal device according to any one of claims 1 to 4, characterized by further comprising an air leg (14), wherein an electric switch valve (16) and an electric flow regulating valve (17) which are arranged in parallel are arranged on an air inlet pipeline (15) or an air outlet pipeline of the air leg (14).

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