CN214083403U

CN214083403U - Full-automatic silk screen printing machine

Info

Publication number: CN214083403U
Application number: CN202022932479.6U
Authority: CN
Inventors: 马占山; 付彦; 廖强莉; 梁小兰; 黄梅鲜
Original assignee: Dongguan Wenjun Industrial Co ltd
Current assignee: Dongguan Wenjun Industrial Co ltd
Priority date: 2020-12-07
Filing date: 2020-12-07
Publication date: 2021-08-31
Anticipated expiration: 2030-12-07

Abstract

The utility model discloses a full-automatic screen printing machine, which comprises an unreeling mechanism, a first buffer tank, a leveling mechanism, a reciprocating type screen printing mechanism, a second buffer tank, a drying mechanism and a reeling mechanism which are arranged in sequence; carry through unwinding mechanism and roll up the membrane, get into leveling mechanism behind first baffle-box and roll up the membrane arrangement, reciprocating type silk screen printing mechanism carries out printing process to rolling up the membrane, gets into drying mechanism behind the second baffle-box and dries the operation, will roll up the membrane rolling through winding mechanism at last, and complete machine simple structure realizes easily, can improve the silk screen printing efficiency of rolling up the membrane effectively, reduces artificial intensity of labour, has good application prospect.

Description

Full-automatic silk screen printing machine

Technical Field

The utility model relates to a silk screen printing equipment field, more specifically say, in particular to full-automatic silk screen printing machine.

Background

The existing screen printing machine mostly adopts manual work or semi-automatic printing, most of the existing screen printing machine can not realize automatic feeding, the material to be printed needs to be manually placed on the screen printing machine, the manual work is needed to be positioned, a large amount of manpower needs to be consumed in the manual feeding mode, more time needs to be consumed, and the printing efficiency is reduced.

SUMMERY OF THE UTILITY MODEL

The utility model provides a full-automatic silk screen printing machine to solve the problem of proposing among the above-mentioned background art. In order to achieve the above object, the utility model provides a following technical scheme: a full-automatic screen printing machine comprises an unwinding mechanism, a first buffer tank, a leveling mechanism, a reciprocating screen printing mechanism, a second buffer tank, a drying mechanism and a winding mechanism which are sequentially arranged;

the unwinding mechanism comprises a transmission mechanism, two unwinding rollers for unwinding the film, a dust removing roller and a static removing assembly, the transmission mechanism drives the unwinding rollers and the dust removing roller to rotate, and the static removing assembly is used for removing static on the film;

the first buffer box and the second buffer box are both rectangular box structures with openings at the tops;

the leveling mechanism comprises a leveling frame and a supporting frame, a leveling assembly is arranged on the leveling frame, and an adjusting roller set and a centering roller are arranged on the supporting frame; the flattening assembly comprises a pair of supporting seats, clamping plates are arranged on the pair of supporting seats, rubber plates are clamped and mounted in the clamping plates, and arc chamfers convenient for rolled films to enter are arranged at the front ends of the rubber plates;

the reciprocating type screen printing mechanism comprises a workbench, a screen printing assembly, a detection assembly and a film drawing assembly are arranged on the workbench, the film drawing assembly is arranged at the rear end of the screen printing assembly, and the detection assembly is arranged between the screen printing assembly and the film drawing assembly; the screen printing component comprises a portal frame, a scraper frame, a bracket and a screen printing plate; the scraper frame is arranged on the portal frame and can move on the portal frame, and the scraper frame comprises a moving seat matched with the portal frame, and a first lifting part and a second lifting part which are arranged on the moving seat; an ink pushing knife is arranged below the first lifting part, and an ink scraping knife is arranged below the second lifting part; the bracket is arranged on the workbench, and the screen printing plate is arranged on the bracket; the detection assembly comprises a clamping arm and a photoelectric sensor, one end of the clamping arm is connected with the workbench, and the other end of the clamping arm is connected with the photoelectric sensor; the film drawing assembly comprises a driving mechanism, a first rotating shaft and a second rotating shaft, and the driving mechanism drives the first rotating shaft and the second rotating shaft to rotate; a pair of rollers which are attached to the film roll are respectively arranged on the first rotating shaft and the second rotating shaft;

the drying mechanism comprises a drying cabinet, and a heater and a plurality of guide rollers are arranged in the drying cabinet;

the winding mechanism is in butt joint with the drying mechanism and receives the film rolls output by the drying mechanism.

Preferably, the winding mechanism comprises a winding cabinet, and a first roller, a second roller, a third roller, a fourth roller, a fifth roller, a sixth roller, a seventh roller, an eighth roller, a ninth roller, a winding roller and a winding motor which are arranged in the winding cabinet, wherein the first roller is used for receiving the winding film conveyed by the drying mechanism; the second roller is arranged below the first roller, the third roller is arranged on the right side of the second roller, the fourth roller is arranged above the third roller, the fifth roller is arranged on the left side of the fourth roller, the sixth roller is arranged on the left side of the fifth roller, the seventh roller is arranged below the sixth roller, the eighth roller is arranged on the right side of the seventh roller, and the ninth roller is arranged above the eighth roller; the winding roller is arranged in the center of the winding cabinet, and the winding motor is in transmission connection with the winding roller.

Preferably, the adjusting roller group comprises an adjusting fixed roller and a rotating roller, the fixed roller is mounted on the support frame, and two ends of the rotating roller are respectively provided with a rotating arm; one end of the rotating arm is rotatably connected with the adjusting and fixing roller and is fastened on the adjusting and fixing roller through star-shaped handle bolts.

Preferably, the centering roller comprises a centering fixed roller and two adjusting blocks, the two adjusting blocks are symmetrically arranged on the centering fixed roller, and the adjusting blocks can slide on the centering adjusting roller and are fastened on the centering fixed roller through star-shaped handle bolts.

Preferably, the ink pushing blade is made of hard plastics, and the ink scraping blade is made of rubber.

Preferably, the first elevating portion and the second elevating portion are both an air cylinder mechanism or a lead screw and nut mechanism.

Preferably, a guide rail and a rack are arranged on the portal frame, the moving seat can slide on the guide rail, a translation motor is arranged on the moving seat, a speed reducer is connected to an output shaft of the translation motor, a gear is arranged at an output end of the speed reducer, and the gear is in meshing transmission connection with the rack.

Preferably, the screen printing device further comprises a ventilation assembly arranged above the screen printing assembly, wherein the ventilation assembly comprises an air suction cover, an exhaust pipe and a negative pressure fan; the back taper structure of the air suction cover is open at the bottom and faces the silk screen printing assembly, the top of the air suction cover is connected with the exhaust pipe, and the other end of the exhaust pipe is connected with the negative pressure fan.

Compared with the prior art, the beneficial effects of the utility model are that: the utility model discloses a unwinding mechanism carries a roll membrane, gets into leveling mechanism behind first baffle-box and rolls up the membrane arrangement, and reciprocating type silk-screen printing mechanism prints the processing to rolling up the membrane, gets into drying mechanism behind the second baffle-box and dries the operation, will roll up the membrane rolling through winding mechanism at last, and complete machine simple structure realizes easily that the silk screen printing efficiency of rolling up the membrane can be improved effectively, reduces artificial intensity of labour, has good application prospect.

Drawings

Fig. 1 is a structural diagram of a full-automatic screen printing machine according to an embodiment of the present invention;

in fig. 1, the corresponding relationship between the names of the components and the reference numbers is:

1-an unwinding mechanism, 11-an unwinding roller, 12-a dust removing roller, 2-a first buffer box, 3-a leveling mechanism, 31-a leveling frame, 32-a support frame, 33-a leveling component, 331-a support seat, 332-a clamping plate, 333-a rubber plate, 34-an adjusting roller set, 35-a centering roller, 4-a reciprocating silk screen printing mechanism, 41-a workbench, 42-a silk screen printing component, 421-a portal frame, 422-a bracket, 423-a silk screen printing plate, 424-a moving seat, 425-a first lifting part, 426-a second lifting part, 427-a ink pushing knife, 428-a scraping knife, 43-a detection component, a first buffer box, a second buffer box, a third buffer box, a fourth buffer box, a third buffer box, a fourth, a fifth, a fourth, a fifth, a, 44- -a film drawing component, 441- -a first rotating shaft, 442- -a second rotating shaft, 443- -a roller, 5- -a second buffer tank, 6- -a drying mechanism, 7- -a winding mechanism, 71- -a winding cabinet, 72- -a first roller, 73- -a second roller, 74- -a third roller, 75- -a fourth roller, 76- -a fifth roller, 77- -a sixth roller, 78- -a seventh roller, 79- -an eighth roller, 710- -a ninth roller, 711- -a winding roller and 8- -an air suction cover.

Detailed Description

The following describes embodiments of the present invention in further detail with reference to the accompanying drawings and examples. The following examples are intended to illustrate the invention, but are not intended to limit the scope of the invention.

In the description of the present invention, "a plurality" means two or more unless otherwise specified; the terms "upper", "lower", "left", "right", "inner", "outer", "front", "rear", "head", "tail", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are merely for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "connected" and "connected" are to be interpreted broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; may be directly connected or indirectly connected through an intermediate. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Referring to fig. 1, the utility model provides a full-automatic screen printing machine, which comprises an unwinding mechanism 1, a first buffer tank 2, a leveling mechanism 3, a reciprocating screen printing mechanism 4, a second buffer tank 5, a drying mechanism 6 and a winding mechanism 7, which are arranged in sequence;

the unwinding mechanism 1 comprises a transmission mechanism, two unwinding rollers 11 for unwinding the film, a dust removing roller 12 and a static removing assembly, wherein the transmission mechanism drives the unwinding rollers 11 and the dust removing roller 12 to rotate, and the static removing assembly is used for removing static on the film;

the first buffer box 2 and the second buffer box 5 are both rectangular box structures with open tops;

the leveling mechanism 3 comprises a leveling frame 31 and a support frame 32, wherein a leveling component 33 is arranged on the leveling frame 31, and an adjusting roller set 34 and a centering roller 35 are arranged on the support frame 32; the flattening assembly 33 comprises a pair of supporting seats 331, a clamping plate 332 is arranged on the pair of supporting seats 331, a rubber plate 333 is clamped and mounted in the clamping plate 332, and an arc chamfer convenient for a rolled film to enter is arranged at the front end of the rubber plate 333;

the reciprocating silk-screen printing mechanism 4 comprises a workbench 41, wherein a silk-screen printing component 42, a detection component 43 and a film pulling component 44 are arranged on the workbench 41, the film pulling component 44 is arranged at the rear end of the silk-screen printing component 42, and the detection component 43 is arranged between the silk-screen printing component 42 and the film pulling component 44; the silk-screen printing assembly 42 comprises a portal frame 421, a scraper frame, a bracket 422 and a silk-screen printing plate 423; the scraper frame is arranged on the portal frame 421 and can move on the portal frame 421, and comprises a moving seat 424 matched with the portal frame 421, and a first lifting part 425 and a second lifting part 426 which are arranged on the moving seat 424; an ink pushing blade 427 is arranged below the first lifting part 425, and an ink scraping blade 428 is arranged below the second lifting part 426; the bracket 422 is arranged on the working table 41, and the screen plate 423 is arranged on the bracket 422; the detection assembly 43 comprises a clamping arm and a photoelectric sensor, one end of the clamping arm is connected with the workbench 41, and the other end of the clamping arm is connected with the photoelectric sensor; the film drawing assembly 44 includes a driving mechanism, a first rotating shaft 441 and a second rotating shaft 442, and the driving mechanism drives the first rotating shaft 441 and the second rotating shaft 442 to rotate; a pair of rollers 443 attached to the film roll are respectively disposed on the first rotating shaft 441 and the second rotating shaft 442;

the drying mechanism 6 comprises a drying cabinet, and a heater and a plurality of guide rollers are arranged in the drying cabinet;

the winding mechanism 7 is in butt joint with the drying mechanism 6 and receives the film rolls output by the drying mechanism 6.

The embodiment of the utility model provides an in, be equipped with drive mechanism in unwinding mechanism 1's the back, drive mechanism mainly used drives the rotation that unreels roller 11 and dust removal roller 12, unreels roller 11 and is provided with two sets ofly, and a set of is last, and a set of is under, can install two membrane simultaneously and roll up, conveniently use up back quick replacement, dust removal roller 12 on generally can set up brush or other soft materials to clean the surface of rolling up the membrane to the process, get rid of dust or other impurity. The static electricity removing component is mainly used for removing static electricity on the roll film and avoiding the static electricity from influencing the conveying and printing operation. The first buffer box 2 and the second buffer box 5 are both of rectangular box structures with open tops, and the rolled film is not in a completely tensioned state in the conveying process but has certain margins, so that the margins can be placed in the boxes. The supporting part of leveling mechanism 3 mainly is leveling frame 31 and support frame 32, and adjusting roller set 34 above support frame 32 is used for the first buffer tank 2 of butt joint, introduces the book membrane in first buffer tank 2, and adjusting roller set 34's angle can be adjusted, conveniently will roll up the membrane and promote not co-altitude position. The centering roller 35 serves to keep the position of the film roll centered and to avoid deviations from affecting the printing effect. The leveling mechanism 3 is mainly realized by a clamping plate 332 and a rubber plate 333 which are arranged on a supporting seat 331, the clamping plate 332 clamps the rubber plate 333 and presses the rubber plate 333 downwards, the front end of the rubber plate 333 is provided with an arc chamfer so as to facilitate the entry of a rolled film, and the rubber plate 333 keeps pressing downwards the rolled film passing through and smooths the rolled film so as to enable the rolled film to enter a printing link in a leveling state. In the reciprocating silk-screen printing mechanism 4, the film drawing assembly 44 draws the roll film to enable the roll film to be conveyed at a certain speed, the detection assembly 43 is used for detecting the arrival condition of the roll film, the mark is aligned through a photoelectric sensor, when the roll film reaches a specified position, the silk-screen printing assembly 42 starts to work, the moving seat 424 on the portal frame 421 can move back and forth along the portal frame 421, the first lifting part 425 and the second lifting part 426 on the moving seat 424 can move up and down, the first lifting part 425 drives the ink pushing knife 427 to lift up and down, the second lifting part 426 drives the ink scraping knife 428 to lift up and down, the portal frame 421 and the moving seat 424 are matched to realize the reciprocating motion of the moving seat 424, through the cooperation of the above components, when the roll film arrives below the screen 423, the first lifting part 425 drives the ink pushing knife 427 to fall, the second lifting part 426 drives the ink scraping knife 428 to rise, then the moving seat 424 drives the first lifting part 425 and the second lifting part 426 to move from one end of the screen printing plate 423 to the other end of the screen printing plate 423, the ink pushing blade 427 pushes the ink away and spreads the screen plate 423; then the first lifting part 425 drives the ink pushing blade 427 to rise, the second lifting part 426 drives the ink scraping blade 428 to fall, the moving seat 424 drives the first lifting part 425 and the second lifting part 426 to return to the initial position, in the moving process, the ink scraping blade 428 applies certain pressure to ink on the screen printing plate 423, meanwhile, the ink moves towards the other end of the screen printing plate 423 at a constant speed, and the ink is extruded onto a roll film from meshes of an image-text part by the ink scraping blade 428 in the moving process, so that the printing operation of the roll film is realized. After the printing is finished, the coiled film is sent into the drying mechanism 6 for drying operation, the conveying direction is changed for many times after passing through the plurality of guide rollers, a longer conveying route is formed in the drying cabinet, and then drying is carried out through the heater. The dried film roll is rolled into a roll through the rolling mechanism 7, so that subsequent operation is facilitated.

Preferably, the winding mechanism 7 comprises a winding cabinet 71, and a first roller 72, a second roller 73, a third roller 74, a fourth roller 75, a fifth roller 76, a sixth roller 77, a seventh roller 78, an eighth roller 79, a ninth roller 710, a winding roller 711 and a winding motor which are arranged in the winding cabinet 71, wherein the first roller 72 is used for receiving the winding film conveyed by the drying mechanism 6; the second roller 73 is arranged below the first roller 72, the third roller 74 is arranged on the right of the second roller 73, the fourth roller 75 is arranged above the third roller 74, the fifth roller 76 is arranged on the left of the fourth roller 75, the sixth roller 77 is arranged on the left of the fifth roller 76, the seventh roller 78 is arranged below the sixth roller 77, the eighth roller 79 is arranged on the right of the seventh roller 78, and the ninth roller 710 is arranged above the eighth roller 79; the winding roller 711 is arranged in the center of the winding cabinet 71, and the winding motor is in transmission connection with the winding roller 711. Through the structural design, the rolled film is driven by the rolling roller 711 to sequentially pass through the first roller 72, the second roller 73, the third roller 74, the fourth roller 75, the fifth roller 76, the sixth roller 77, the seventh roller 78, the eighth roller 79 and the ninth roller 710, so that the rolled film is fully contacted with air in a limited space, and the dried rolled film is fully cooled.

Preferably, the adjusting roller set 34 includes an adjusting fixed roller and a rotating roller, the fixed roller is mounted on the supporting frame 32, and two ends of the rotating roller are respectively provided with a rotating arm; one end of the rotating arm is rotatably connected with the adjusting and fixing roller and is fastened on the adjusting and fixing roller through star-shaped handle bolts. Through the structural design, when the angle of the rotating roller needs to be adjusted, the rotating roller can be rotated along the adjusting fixing roller by loosening the star-shaped handle bolt, and after the rotating roller rotates to a position, the star-shaped handle bolt is screwed down, so that locking can be realized.

Preferably, the centering roller 35 comprises a centering fixing roller and two adjusting blocks, the two adjusting blocks are symmetrically arranged on the centering fixing roller, and the adjusting blocks can slide on the centering adjusting roller and are fastened on the centering fixing roller through star-shaped handle bolts. Through the structural design, when the position of the adjusting block needs to be moved, the adjusting block can slide along the centering fixing roller by loosening the star-shaped handle bolt, and after the adjusting block is moved in place, the star-shaped handle bolt is screwed down to realize locking.

Preferably, the material of the ink pushing blade 427 is rigid plastic, and the material of the ink scraping blade 428 is rubber.

Preferably, a guide rail and a rack are arranged on the portal frame 421, the moving seat 424 can slide on the guide rail, a translation motor is arranged on the moving seat 424, a speed reducer is connected to an output shaft of the translation motor, a gear is arranged at an output end of the speed reducer, and the gear is in meshing transmission connection with the rack. Through the above structural design, the moving seat 424 is driven by the meshing of the gear and the rack, and the running speed is fast and stable.

Preferably, the screen printing device further comprises a ventilation assembly arranged above the screen printing assembly 42, wherein the ventilation assembly comprises an air suction hood 8, an exhaust pipe and a negative pressure fan; the back taper structure of aspiration channel 8, its bottom opening and orientation silk screen printing subassembly 42, the top is connected the exhaust pipe, the other end of exhaust pipe with negative-pressure air fan connects. Through setting up the subassembly that ventilates, negative pressure fan starts and makes near 8 formation negative pressures of cover that induced drafts, can absorb near dust and the peculiar smell of silk screen printing mechanism rapidly, avoids polluting the operation environment.

The embodiments of the present invention have been presented for purposes of illustration and description, and are not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiment was chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.

Claims

1. A full-automatic screen printing machine is characterized by comprising an unwinding mechanism (1), a first buffer tank (2), a leveling mechanism (3), a reciprocating screen printing mechanism (4), a second buffer tank (5), a drying mechanism (6) and a winding mechanism (7) which are sequentially arranged;

the unwinding mechanism comprises a transmission mechanism, two unwinding rollers (11) for unwinding the film, a dust removing roller (12) and a static removing assembly, the transmission mechanism drives the unwinding rollers and the dust removing roller to rotate, and the static removing assembly is used for removing static on the film;

the leveling mechanism comprises a leveling rack (31) and a support frame (32), a leveling component (33) is arranged on the leveling rack, and an adjusting roller set (34) and a centering roller (35) are arranged on the support frame; the flattening assembly comprises a pair of supporting seats (331), clamping plates (332) are arranged on the supporting seats, rubber plates (333) are clamped and mounted in the clamping plates, and arc chamfers convenient for rolled films to enter are arranged at the front ends of the rubber plates;

the reciprocating type screen printing mechanism comprises a workbench (41), a screen printing assembly (42), a detection assembly (43) and a film pulling assembly (44) are arranged on the workbench, the film pulling assembly is arranged at the rear end of the screen printing assembly, and the detection assembly is arranged between the screen printing assembly and the film pulling assembly; the silk-screen printing assembly comprises a portal frame (421), a scraper frame, a bracket (422) and a silk screen printing plate (423); the scraper frame is arranged on the portal frame and can move on the portal frame, and the scraper frame comprises a moving seat (424) matched with the portal frame, and a first lifting part (425) and a second lifting part (426) which are arranged on the moving seat; an ink pushing blade (427) is arranged below the first lifting part, and a scraping blade (428) is arranged below the second lifting part; the bracket is arranged on the workbench, and the screen printing plate is arranged on the bracket; the detection assembly comprises a clamping arm and a photoelectric sensor, one end of the clamping arm is connected with the workbench, and the other end of the clamping arm is connected with the photoelectric sensor; the film drawing assembly comprises a driving mechanism, a first rotating shaft (441) and a second rotating shaft (442), and the driving mechanism drives the first rotating shaft and the second rotating shaft to rotate; a pair of rollers (443) attached to the film roll are respectively arranged on the first rotating shaft and the second rotating shaft;

2. The full-automatic screen printing machine according to claim 1, wherein the winding mechanism comprises a winding cabinet (71), and a first roller (72), a second roller (73), a third roller (74), a fourth roller (75), a fifth roller (76), a sixth roller (77), a seventh roller (78), an eighth roller (79), a ninth roller (710), a winding roller (711) and a winding motor which are arranged in the winding cabinet, wherein the first roller is used for receiving the winding film conveyed by the drying mechanism; the second roller is arranged below the first roller, the third roller is arranged on the right side of the second roller, the fourth roller is arranged above the third roller, the fifth roller is arranged on the left side of the fourth roller, the sixth roller is arranged on the left side of the fifth roller, the seventh roller is arranged below the sixth roller, the eighth roller is arranged on the right side of the seventh roller, and the ninth roller is arranged above the eighth roller; the winding roller is arranged in the center of the winding cabinet, and the winding motor is in transmission connection with the winding roller.

3. The full-automatic screen printing machine according to claim 1, wherein the adjusting roller set comprises an adjusting fixed roller and a rotating roller, the fixed roller is mounted on the support frame, and two ends of the rotating roller are respectively provided with a rotating arm; one end of the rotating arm is rotatably connected with the adjusting and fixing roller and is fastened on the adjusting and fixing roller through star-shaped handle bolts.

4. The full-automatic screen printing machine of claim 3, wherein the centering roller comprises a centering fixed roller and two adjusting blocks, the two adjusting blocks are symmetrically arranged on the centering fixed roller, and the adjusting blocks can slide on the centering adjusting roller and are fastened on the centering fixed roller through star-shaped handle bolts.

5. The automatic screen printing machine according to claim 1, wherein the ink pushing blade is made of rigid plastic, and the ink scraping blade is made of rubber.

6. The full-automatic screen printing machine according to claim 1, wherein the first elevating portion and the second elevating portion are both cylinder mechanisms or lead screw and nut mechanisms.

7. The full-automatic screen printing machine according to claim 1, wherein a guide rail and a rack are arranged on the gantry, the movable base can slide on the guide rail, a translation motor is arranged on the movable base, a reducer is connected to an output shaft of the translation motor, and an output end of the reducer is provided with a gear which is in meshed transmission connection with the rack.

8. The full-automatic screen printing machine according to any one of claims 1 to 7, further comprising a ventilation assembly arranged above the screen printing assembly, wherein the ventilation assembly comprises an air suction hood (8), an exhaust duct and a negative pressure fan; the back taper structure of the air suction cover is open at the bottom and faces the silk screen printing assembly, the top of the air suction cover is connected with the exhaust pipe, and the other end of the exhaust pipe is connected with the negative pressure fan.