FI95611B - Method and apparatus for collecting and removing dust released from a web by a paper machine or its finishing device - Google Patents

Description

95611

Method and apparatus for collecting and removing dust detached from a web on a paper machine or its finishing device For the production and removal of dust from a paper machine or for the subsequent handling of a paper for the same time as a blanket for a loss of banana

The invention relates to a method for collecting and removing dust and the like detached from a web by a paper machine or its post-processing device, in particular a slitter, in which method a blow is applied to the web to remove dust from the web and a suction effect is applied to the web.

The invention further relates to a device for collecting and removing dust and the like detached from a web on a paper machine or its post-processing device, in particular a slitter, the device comprising an overpressure chamber with a nozzle opening for blowing the web and a suction opening (s) for removing dust in connection with the web.

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Dust and dirt, for example debris and fibers from the drying section of the paper machine, are trapped on the surface of the paper web after papermaking. Another perhaps most significant source of dust is the slitting process itself. This dust and dirt cause problems in the further processing of the paper, especially in printing, because keeping the printing rollers 25 clean is essential for the quality of printing.

In addition, the dust spreads to the environment both at the paper mill and in further processing and may have occupational health hazards as it may contain various filler particles.

30 With regard to the prior art, reference is made to FI patent publications 78 944 and 82 105, which disclose in particular dust removal devices and methods used in the manufacture of tissue paper.

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F1 patent publication 78 944 discloses a method and apparatus for collecting and removing dust detached from a web on a paper machine, in which it is considered substantially new to apply blows to the web which both non-contactly support and remove dust from the moving paper web and at least partially transport the dust. to the collection. In order to implement the method, it is considered new that the device comprises one or more dust extraction boxes with two nozzle boxes separated by intermediate spaces, with coanda nozzles blowing in opposite directions on the sides or the like, that said space is connected to a vacuum suction space and that said vacuum extraction box is a rear suction space which opens against a passing web and is connected to a vacuum suction space.

F1 Patent Publication No. 82,105 discloses a method for discharging dust released during tissue stripping by a creping scraper from a Yankee cylinder, wherein some of the dust travels along a boundary layer of air which entrains and follows the track as the track travels from the Yankee cylinder to the reel. It has been considered new to the method that a dust extraction device with an inner space and a uniform level stabilizing the track is fitted immediately against the path for the creped track so that the track gets 20 defined positions tightly against a uniform plane and that at least substantially boundary layer. This patent also discloses an apparatus for carrying out the method, which is considered to be novel in that the apparatus comprises a track-wide passage with a front side edge and a rear side edge in the track conveying direction, a uniform flat cover plate arranged to close the passage substantially limiting the interior space and forming a gap between at least one of said side edges and the cover plate, means for applying a vacuum to the interior space by sucking air through the gap, the device being intended to be mounted so that the cover plate is directly against the creped track transport path, the flat cover plate providing a track stabilizing effect so that the track, when passing, acquires an exact position tightly against the cover plate and the gap will be located in the boundary layer containing dust.

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Referring to the prior art, reference is also made to U.S. Patent No. 4,715,078, which discloses a method and apparatus for cleaning the edges of a paper web used with a slitter and removing dust from the edges. The device uses two cleaning rollers strategically placed in the path of the paper web. The first cleaning roller 5 contacts the front edge of the paper web as the paper web advances from the slitter. As the paper web travels forward, its upper surface is also cleaned with the same roller. The second cleaning roller cleans the latter edge of the paper path as it travels forward. This roller also cleans the underside of the paper path. The vacuum system then removes the particles that are removed by the cleaning rollers and also cleans all four edges of the paper web. The pressure system removes the particles from the surface of the paper web so that they can be transported away by the vacuum system.

U.S. Patent No. 3,239,863 discloses a web cleaning apparatus using a chamber space formed with two air nozzles per track, the space between the nozzles 15 of which is closed so as to form an exhaust chamber for air from the nozzles and dust escaping from the track.

One problem with these known devices is to provide a sufficient air blowing speed to remove dust trapped in the track and the fact that the devices have had to be constructed quite far from the track, making them mainly suitable for general dust removal but not removing dust and dirt from the track.

The object of the invention is to provide a dust removal method and a device by means of which adhering dust and dirt can also be removed from the track, as well as to clean the environment from dust and / or to prevent the spread of dust to the environment.

It is also a further object of the invention to provide a dust removal device which can be used close to the web without risking damage to the paper web.

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It is a further object of the invention to provide such a device which can be moved out of the way of the track in the event of a track break and / or during the removal of the track.

In order to achieve the above and later objects, the method according to the invention is mainly characterized in that the method is subjected to a high-pressure blowing to remove dust from the web and that in the method in the web direction before and after said high-pressure blowing dust and the like are sucked from the web.

Furthermore, the device according to the invention is mainly characterized in that the air chamber of the device is high pressure, through which the nozzle opening of the air chamber is arranged to blow high pressure, and that the suction openings of the device are located before and after said nozzle opening in the web direction.

The device according to the invention makes it possible to remove dust and dirt adhering to the surface of the web, which cause problems in the further processing of paper. In addition, the dust load in the data center is reduced, which also improves the working environment.

According to a preferred embodiment of the invention, the device consists of two blowing nozzles, one of which is a high-pressure dust extraction nozzle and the other a low-pressure air curtain nozzle to prevent loose dust from entering the computer room and two suction zones for suction dust and dirt. The device is connected to an air system that transports dirty air to a wet separator or other similar filter, from which the air is led either out of the computer room or back to the computer room.

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In the nozzles according to the invention the distance of the blow to the track is very small, 2 ... 5 mm, preferably only about 2-3 mm and the air space pressure of the first nozzle is 20,000 ... 30,000 Pa, preferably 20,000 ... 25,000 Pa and the air space pressure of the latter nozzle 300 ... 1000 Pa, preferably 300 ... 500 Pa, e.g. about 30 400 Pa.

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In a preferred embodiment, the blow nozzle gap is 0.5 mm and a blow speed of 200 m / s is used. The suction nozzles use a high duct speed, about 25 ... 50 m / s, preferably about 30-40 m / s, so that the dirt in the air does not stick to the duct walls.

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The method and devices according to the invention can be used with a paper machine and its post-processing device, especially in connection with a slitter. In the slitter, the dust removal devices are placed as close as possible to the slitter itself on each side of the track after the slitter.

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In connection with the device, measuring and control devices are arranged, by means of which the distance of the device to the track is kept desired and by means of which, in the event of a track break or other disturbance, the device can be moved off the track. The device is movably attached to the frame structures of the machine.

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In the method according to the invention, the dust is removed from the track and the dust is removed and the track is kept far enough but at the same time close enough to the blowing device.

In the following, the invention will be described in more detail with reference to the figures of the accompanying drawing 20, the details of which, however, are not intended to be limited in any way.

Figure 1 shows a schematic vertical cross-section of a device according to the invention.

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Figure 2 shows a schematic vertical cross-section of a device according to the invention fitted to a slitter in the driving position.

Figure 3 shows the situation shown in Figure 2 in the track head position.

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Figure 4 shows a schematic view of a device according to the invention in the width direction of the track.

Figure 5 shows a schematic air diagram for a device according to the invention.

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Figure 6 shows a schematic application example of an arrangement according to the invention with a slitter.

In the schematic embodiment of the invention shown in Fig. 1, a dust removal device 10 is arranged above the web W. The web W advances in the direction S. The device 10 comprises an overpressure chamber 11 into which blowing air is introduced along the duct 14. A strong blow Pj is blown from the nozzle opening 12 of the chamber 11 towards the web so that the dirt and dust particles D attached to it are released from the web W. Before the blowing opening 12 there is a suction opening 13 which removes loose dust and dirt particles D through the suction opening 13 15 to the suction duct 15 16. The blow P1 to be blown from the nozzle opening 12 is high pressure, while the blow P2 leading from the chamber 21 to the blow opening 22 is low pressure and acts as an air curtain nozzle to prevent loose dust D from entering the computer room and further with the web W. Air is introduced into the blowing chamber 21 along the duct 24 20. Between the first blow nozzle 12 and the second blow nozzle 22 there is a second suction opening 23 which further sucks any intermediate dirt and dust particles D into the suction duct 25 and further into the outlet duct 16. The device also comprises a chamber 31 from which blowing air 32 used in the head export of the web W (Fig. 3).

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The blowing Pj removes dust from the web W and at the same time keeps the web W far enough away from the structures of the device 10. The nozzle openings 12,22 are continuous slit nozzles with a slit width of 0.2-1 mm, preferably e.g. 0.5 mm. The nozzle openings 12,22 extend in the width direction of the web W over the entire substantial width of the web W. The distance E of the device 10 from the track 30 is 2-6 mm, preferably 2-3 mm while driving. The blowing speed of the blowing Pj is e.g. 150 - 200 m / s and the pressure used in the chamber 11 is 20,000 ... 30,000 Pa, preferably 7,95611 20,000 - 25,000 Pa. The blowing speed of the blowing P2 is e.g. 30 ... 50 m / s and the pressure used in the chamber 21 is 500 ... 1500 Pa, preferably about 500 ... 750 Pa. The suction speed in the suction openings 13,23 is 25 to 50 m / s, preferably about 30 to 40 m / s. The slit width of the suction opening 13,23 is about 5-20 mm, preferably 10-15 mm. The basic starting point for dimensioning is that air is sucked in from the 5 suction openings 13,23 about twice as much as when blown through the nozzle openings 12,22. This ensures that the dust released from the web does not spread to the environment. The second blow nozzle 22 provides a blow P2, which, as described above, acts as an air curtain nozzle, which prevents any dust passing past the suction opening 23 from further passing with the web W and also the dust 10 from spreading into the environment.

The suction openings 13 and 23 are preferably provided with a torn plate / net 17, 27, which prevents, for example, the chipping caused by the rupture of the track W from entering the device 10.

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The device 10 is formed of plate structures shaped in the form of the necessary chambers and channels, which are connected to each other by fastening members 61, which allow the parts to be detached from each other for cleaning the device 10. The nozzle plates 18 of the first nozzle opening 12 are made by machining, whereby the accuracy of the nozzle opening 12 is made sufficient. The nozzle plates 18, 18 'are also fastened to each other by a fastening member 61, whereby the cleaning of the chamber 11, as well as the cleaning of the nozzle opening 12, is easy.

In Fig. 2, an application example of the device according to the invention is placed in connection with a web guide roll 49 after a longitudinal section. The device 10 is in the driving position, in which case it operates as described above in connection with Figure 1. The device 10 is attached to the other frame structures 100 of the machine in a manner known per se, and the passage of the web W is also controlled by an auxiliary roller 101 arranged in connection with the device 10.

In Figure 3, the device 10 has been moved away from the vicinity of the track W during the export of the end D of the track W. In this case, a nip N is formed between the auxiliary roll 101 and the web guide roll 49, through which the end D of the web W is guided. Blows P3 are blown from the blowing chamber 31 of the device 10, which assist in the export of the end of the track W.

Fig. 4 shows a schematic sectional view of a dust removal device 10 placed on the spread (bent) track W 5. The device 10 is divided into the required number of blocks 10 ', whereby the blows can be arranged according to the curvature of the track W. There are 3 ... 5 blocks, preferably 3, depending on the width W of the track. The distance E 'of the blocks 10' from the track W is measured by measuring devices 40 ', e.g. at the junction of the blocks 10', and the distance information is transmitted to the control device 50.

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Figure 5 shows a schematic air diagram. Dust is sucked from the track W through the suction zones 13,23 to an outlet duct 16, from which the air containing dust is led to a scrubber 53, to which water is introduced via a valve 54. After the scrubber 53, the air is led to the dust separator 55, after which the air is led out via the exhaust fan 56 or back to the computer room.

The clean filtered air is led through the blowing air blower 52 to the blowing air ducts 14,24 and further to the blowing chambers 11,21, from which a dust removal blow Pj is blown from the chamber 11 according to Fig. 1 towards the path W and an air curtain blowing P2 is formed from the chamber 21.

A measuring device 40 is arranged in connection with the device 10, which measures the distance E of the device 10 from the track W, e.g. by ultrasonic or laser measurement. The distance information from the measuring device 40 is transmitted to the control device 50, which adjusts the distance E of the device 10 from the paper web W 25 to the desired, 2-6 mm, preferably 2-3 mm. The position of the device 10 relative to the path W is continuously adjusted, because, for example, the spreading roller applied by the spreading rollers after the slitter can move up to 150 mm.

The control device 50 controls the movement of the device 10 in the machine frame structures 100. The transfer arrangements of the device 10 30 can be implemented with guide and / or 9 95611 other similar arrangements known per se to a person skilled in the art. The control device 50 also controls the operation of the device so that, for example, in the event of a track break, the device is moved out of the way of the track W.

Figure 6 shows devices according to the invention, fitted in connection with a slitter 45 5. The slitter 45 cuts partial tracks of the desired width from the full-width track W, which are rolled into customer rolls by the winder 48. One device according to the invention is placed at the track guide roller 49 after the slitter 45 on the opposite side of the track W, the next before the spreading rollers 46 on the same side of the track W, but on the opposite side from the previous device. Finally, the path W is fed 10 to the winder 48.

The invention has been described above only with reference to some of its preferred embodiments, the details of which, however, are not intended to be limited in any way. Many variations and modifications are possible within the scope of the inventive idea defined in the following claims 15.

Claims (16)

A method of a paper machine or a finishing machine for a seed, in particular a longitudinal cutting device, for collecting and removing dust (D) and the corresponding discharge from the web (W), in which method a blow (Pj) is directed towards the web. (W) releasing dust (D) from the web (W) and by which method a suction effect (Ij, I2) is directed towards the web (W), to remove dust (D) discharging from the web (W), characterized in that , in the process, a high pressure blow (Pj) is directed towards the web (W) to release dust (D) from the web (W), and in the running direction (S) of the web, before and after said blow (Pj ) under high pressure sucks dust and the equivalent that discharged from the web (W). 2. A method according to claim 1, characterized in that the process sucks two times as much air as one blows. 15 3. A method according to claim 2, characterized in that in the process after the blowing (Pj) under high pressure, a blowing (P2) under low pressure is directed towards the web (W) in the running direction (S) of the web with which the dust ( D) which is unloaded is transported further and spread out. 20 Method according to Claim 2 or 3, characterized in that in the process the blisters (Pj, P2) are blown against the web (W) from a distance (E) of 2 ... 6 mm, most preferably about 2 ... 3 mm. from the web (W). 25 5. A method according to any of claims 1-4, characterized in that the distance (E) of the blows (Pj P 2 from the web (W) and the distance (E) is continuously controlled during the running of the web (W)). . Method according to any of claims 1-5, characterized in that, for the time of the tip drawing of the web (W), the blow (Pj) for the dust release and the air slide blow (P2) are closed and a third blow (P3) is blown for to promote lace drawing. Process according to any of claims 1-6, characterized in that the dust release blow (Pj) is blown at a speed of about 150 ... 200 m / s. Method according to any of claims 1-7, characterized in that the air slide blow (P2) is blown at a speed of about 30 ... 50 m / s. Apparatus on a paper machine or post-processing device for a seed, in particular a longitudinal cutting device, for collecting and removing dust (D) and the corresponding discharge from the web (W), which device (10) comprises an overpressured chamber space (11). ), wherein there is a nozzle opening (12) for directing a blow (Pj) towards the web (W), and a suction opening / suction openings (13,23) for removing dust (D) in connection with the web (W), characterized in that the air chamber (11) of the device (10) is under high pressure, whereby through the nozzle opening (12) of the air chamber (11) a blow (Pj) can be blown under high pressure against the web (W), and that the suction openings (13, 23) of the device (10) are placed before and after said nozzle opening (12) in the running direction (S) of the web (W). 20 Device according to claim 9, characterized in that the second air chamber (21) of the device (10) is under low pressure, whereby a blow (P2) is directed towards the web (21) of the air chamber (21). W) acting as an air curtain. 25 Device according to claim 9 or 10, characterized in that the device comprises means (40, 50) for measuring the distance (E) of the web (W) from the device (10) and for controlling this in such a manner that the desired distance ( E) from the device (10) to the web (W) is maintained. 30 15 95611 Device according to any of claims 9-11, characterized in that the device further comprises a third air chamber (31), whereby a blow (P3) is arranged to blow a blow (P3) at the tip of the web (W). Device according to any of the preceding claims, characterized in that the device is formed of structures which are releasably attached to each other by means of fastening means (61) for detaching the structures from each other for cleaning of the device. Device according to any one of the preceding claims, characterized in that the nozzle openings (12, 22) for the dust release and air release blow (Pj P 2) extend over a substantial width of the web (W) and said nozzle openings (12, 22). ) are heel pieces. Device according to any one of the preceding claims, characterized in that the suction openings (13, 23) are provided with a heel plate (17, 27) to prevent paper or other tensioning of the device (10). Device according to any of the preceding claims, characterized in that the device (10) is formed by section (10 ') in such a way that the shape of it against. the surface (10) of the web (W) substantially follows the curvature of the web (W) in the width direction of the web (W).