MXPA00011340A - Method and device for removing dust from a moving paper web - Google Patents

Abstract

To separate and extract dust from a moving web, especially of tissue paper, the layer of air carried by the moving web is deflected away from the web surface and extracted by suction. It is passed through a separation box which extracts the air evenly across the web width. At the same time, the air carried by the web is separated from its under side by suction. When the dust-laden air is removed, it is replaced by ambient air to prevent the formation of eddies. The web is stabilized before the carried air is separated, and air carried by the stabilizer is led away. An Independent claim is included for an assembly to free the moving tissue paper web of dust with an initial separation box (9) as a stabilizer across the web width, with a curved guide surface (18) for the web (4). A surface air deflector is at the entry side of the separation box (9), to direct the air into a collection channel (21) at the separation box (9). The collection channel (21) has an expanding cross section towa rds the drive side of the papermaking machine. An adjustable suction slit (19) is at the entry side (18') of the separation box (9). The separation box can be opened across the whole width. A second separation box (10) is under the web (4), where the web runs into it at a small angle pref. of 1-5 degrees and such as 1-2 degrees. The second separation box (10) has a deflection plate (23), pref. with a swing movement, and the box is divided into at least two chambers. A stabilizer (8) is in front of the leading separation box (9), which spreads the paper web (4) across its width, pref. with a swing movement. A funnel-shaped suction hood is at the zone of the scraper (6), on the machine drive side. A further separation box (12) is over the paper web (4).

Description

PROCEDURE AND DEVICE FOR THE REMOVAL OF DUST FROM A PAPER TRACK IN MOTION. FIELD OF THE INVENTION The invention relates to a method for removing dust from a moving track or paper web, particularly a tissue or crepe paper track, where the air moving along the fabric and having a high content of dust is removed from the boundary layer. Furthermore, the invention relates to a device for carrying out the process with a first separator box mounted through the direction in which it runs. BACKGROUND OF THE INVENTION When making tissue or tissue, 1 to 2% of the production, depending on the starting material, the final dry product and the introduction of chemical agents, is collected as a powder in the crepe sector. On the other hand, this dust has a negative effect on production and also produces a risk to health and safety for the working group. Due to the tendency toward softer tissue grades and the use of more mechanical pulp, the dust problem continues to increase. The powder comprises fine particles, and fragments of fiber that are removed from the paper web, especially from the crepe and / or curly sector, some of the dust falls on the fourth floor of the machine and remains It is dragged along with the limiting air layer on both sides of the ditch track in Lanto which is transported from the curling sector by the winding coil. Part of the dust remains on the surface of the paper tray, which causes greater difficulties in the finishing process. SUMMARY OF THE INVENTION The invention aims to create a procedure and a device where the dust generated on a paper track with high speed, particularly a woven track, is removed in such a way that the permissible limit values for the powder are not exceeded. - at the same time, - the performance of the papermaking machine is increased, particularly the weaving machine or the manufacturer of ~ t ± ssue. The invention is characterized in that the paper track runs tangent to and outside the curved surface of a separator box, designed as a stabilizer, and by air deflects off of the boundary layer and is removed by the separating box. Since the separator box is designed as a stabilizer ± a-ist is accurately guided and the susceptibility to tearing of the sheet is substantially reduced because the track runs on and away from the curved guide surface as a tangent. This effect is further improved, because "the air is diverted from the border layer, towards the separating box and removed from there, so the eddies and the overpressure of another tear of the paper track are conducted in those places. air of the dust-free environment, and with this the corresponding pressure is re-established.Another favorable conformation of the invention is characterized in that the paper track is stabilized before air separation, where the air entrained by the stabilizer can deviating, the stabilization of the paper track, before the air separation facilitates the conduction of the runway and thus reduces the risk of tearing in the runway, if the entrained air is diverted by the stabilizer, even before the air separation itself can be removed a part of the powder.In addition, the invention considers a device for the separation of dust from a moving paper track especially b walk or track Tissue or woven with a first separation box that runs transversely to the paper track. It is characterized in that, the first separation box is constructed as a stabilizer with a curved guide surface for the paper track and has a device for deflecting the powder boundary layer in an accumulation channel of the separation box. Due to the shape of the separation box as a stabilizer with a curved guide surface, a good conduction of the track is achieved and with this the danger of tearing the paper web decreases. The simultaneous removal of the boundary layer or 5 border of the air in an accumulation channel, allows a good dust removal from the paper track that moves quickly. Another embodiment of the invention is characterized in that the accumulation channel has a cross section that widens towards the drive side of the machine. This achieves that the air is removed from the width of the track uniformly, and this does not produce any pressure or local sub-pressure that could lead to a tear of the track. Another advantageous embodiment of the invention is characterized in that, on the paper running side of the first separation box, a suction groove is provided, which is preferably made to be adjustable. Through the suction slot provided, the air with the powder can be removed in a planned manner, where the adjustment capacity allows the amount corresponding to the precipitation to be removed. Another favorable conformation of the invention is characterized in that, the separation box is wide-open. By means of this embodiment a convenient cleaning is possible, which is of particular importance in the air charged with dust in a humid environment. Another advantageous embodiment of the invention is characterized in that another separation box is provided on the lower side of the paper track, wherein the paper track runs at a very small angle, preferably from 1 to 5 °, for example from 1 to 2 °. By another box of separation in the inferior side of paper, allows an additional dust removal, where the march with a very small angle allows a better guidance of the track, and with that less tears in the sharp edges. Another advantageous embodiment of the invention is characterized in that the additional separation boxes have a deflection sheet, which is preferably made incunably. With this deflection sheet air can be conducted directly to the separation boxes, where the incunable embodiment allows adjusting the amount of air to be separated. Another favorable conformation of the invention is characterized in that, the lower separation box is divided into at least two chambers, by this embodiment the air can be separated before and after the separation box in a manner and the amount diverted, so that a stable driving of the track is guaranteed without tearing. A favorable conformation of the invention is characterized in that a stabilizer is provided in front of the first separation box that exerts a stretching effect across the paper track, where the stabilizer can be made to be tiltable. By 7 this additional stabilizer is achieved a still more stable track driving. Thanks to the pivotable design, the ideal web tension is guaranteed, and even in the tearing of the web, this stabilizer can be removed before continuing with the guidance of the paper track. Another advantageous embodiment of the invention is characterized in that a funnel-shaped suction hood is provided in the scraper area of the paper machine. Because of such a possibility of suction also during a tear of the strip and a new conduction of the paper track, the powder produced in the scraper can be removed more surely and thereby reduce the dust load. An advantageous embodiment of the present invention is characterized in that another separation box is provided on the upper side of the paper. By this measure the last remnants of the powder still adhering to the upper side of the paper track can be removed before the paper track is wound up. BRIEF DESCRIPTION OF THE DRAWINGS Next will be described by way of example with reference to the drawings, where it shows: FIGURE 1, the scheme of a dust removal system in a crepe paper machine; FIGURE 2, a detailed representation of the 8 individual elements of the system; FIGURE 3, a view of a top separation box; FIGURES 4A and 4B, cuts through FIG. 3; FIGURE 5, a view of a lower separation box; FIGURES 6A AND 6B, cuts through FIG. 5. DETAILED DESCRIPTION OF THE INVENTION FIG. 1, shows the scheme of a dust removal from a paper track, at the end of the papermaking process is found the paper dryer 1, with a dryer cylinder 2, and a dryer hood 3, from which the hot air is blown on the paper track 4, which is conducted around the dryer cylinder 2. The paper track is conducted in the still on the pressing rollers 5, 5 '. After the paper drying is performed, the paper track 4 is scraped off by means of a scraper 6 from the drying cylinder 2. This results in a large amount of dust on the one hand, and on the other hand fibers are easily separated. the paper surface. But in the event of a tear of the paper track accumulating the paper and still being able to use it again, it is located under the scraper 6, a so-called scrap container 7. To improve the driving of the track, after the scraper 6, a scraper 6 is provided. stabilizer 8. A part of the air entrained and charged with 9 dust collides in the stabilizer and is conducted to the waste container 7, from which this air is sucked. In case of a tear of the paper track, this stabilizer can be moved downwards, so that later the paper track can be driven again without any problem. In connection with this stabilizer 8, an air separator box is located on the upper side of the paper track, which performs another additional stabilization of the track and separates the air from the upper side of the paper track. There, another separating box 10 is connected, on the underside of the paper track, where the air dragged by the lower side and loaded with dust deviates, only by the dynamic pressure of the entrained air, which is already removed and hardly Suction may be necessary. Next to the lower separation box 10, there is a measuring apparatus 11, traversed to measure the properties of the paper track. Another separation box 12, is provided on the upper side of the track to remove more dust before the track is fed onto a work roll 13, and wound onto the coil 14. All the air streams charged with air are They are removed through a dust collector 15, where the dust is removed by introducing water. The air is finally sucked by a fan 16, and the water charged with dust is drained to a tank 17, and from there it is discharged as waste water.

Fig. 2, now shows the dust suction part in detail. Here the drying cylinder 2 is recognized, from which the paper track 4 is scraped by a scraper 6. A part of the dust-laden air is diverted by means of the stabilizer 8, made incunable downwards towards the waste tank 7. From here on, the paper is fed to the separation box 9, which has a curved guide surface 18 for the stable guidance of the paper track. The paper track runs here at the inlet 18, tangential to this separation box. 9, and leaves the separation box by the exit 18", also tangentially. By means of this curved guide surface 18, the necessary track tension is produced, so that a stable guide band is always guaranteed, at the inlet 18 'the air conveyed by the paper web is deflected and guided into a groove. suction 19. The wall 20, of the suction groove 19, is made in an articulated manner, with which the suction groove 19 is made adjustable. For cleaning the separation box this wall 20 can be completely folded upwards and With this, the suction channel 21 is free to carry out cleaning. The internal surfaces of the separation box are smooth and do not have any edge, corner or special place where dust can accumulate. Also in that way a cleaning of the separation box is facilitated. After the paper track has passed 11 through the outlet 18"of the separation box 19, the paper track 4 is led to a lower separation box 10. Here, the paper track is located at a small angle preferably from 1 to 5o, for example from the 2nd, which again leads to good track guidance. The entrained air is led here by means of a suction groove 22, to the case 10. This suction groove 22 has an incunable foil 23, which is designed to be adjusted and thus achieve an optimum air separation. At the outlet of the paper path of the separation box 10, air can be supplied to prevent swirling and with this a new generation of dust upon sub-pressure. After the passage of the paper track through a crossed measuring device 11, the track is guided by means of another separation box 12, which is made analogously to the lower separation box 10. The track of paper 4, by rollers 13, is wound on the drum 14. Fig. 3, shows a view of a separation box 9, where the drive side is marked here to the left (indicated with TS), and to the right the so-called guide side (indicated with FS) of the paper machine, the air by means of a suction tube 25, is taken out from the discharge side from the separation box 9. Figs. 4a and 4b, show a cross section 12 of the separation box 9, in the vicinity of the guide side according to the line A-A, or in the vicinity of the drive side according to the line B-B. Here it is recognizable that the section of the suction channel 21 grows from the introduction side or the driven delivery guide. This achieves that the speeds at all points remain approximately constant over the width of the track. With this there is no difference in air suction and the danger of tearing on the track is reduced. In Figs. 4a and 4b, the guidance or guidance of the paper track 4, which is realized by means of the guide surface 18, of the separation box 9 is clearly recognized. At the entrance 18 'or at the exit 18", it runs the paper track entering or exiting tangentially and it is ensured by the conformation of the entrance 18 'or of the exit 18' 'that no other generation of dust is reached by the deviation. The air from the boundary or border layer is guided through the suction groove 19 to the accumulation channel 21. The chamber wall 20 is made incunable, so that on the one hand the suction groove 19 can be adjusted., and on the other hand, the separation box 9 is also opened for cleaning. Fig. 5, now shows the view of a lower separation box 10, again the drive side is to the left and to the right the guidance of the paper machine 13, where the suction is carried out on the side of the machine. driving through a conduit 26, 27. Fig. 6a, shows the cross section of the separation box 10, on the guide rail according to the line CC. Here the course is well recognized approximately in a plane of the paper track 4, on the separating box 10. The air is conducted by means of the deflection sheet 23, to the separating box 10. more air can in the passage of the paper track 4, sucked from the separation box 10, by means of an opening 28. In Fig. 6, the cross section of the separation box 10 is shown, on the drive side by means of a line DD, here also the suction cross sections 26 and 27 are recognized. The invention is not limited to the embodiments shown.

Claims (14)

14 NOVELTY OF THE INVENTION Having described the invention as above, the content of the following claims is claimed as property: CLAIMS 1. - Procedure for separation of dust from a paper track in movimieiiLu, especially crepe runway, where air entrained and charged with powder with the paper web separates from the boundary r, characterized in that, it runs tangentially in and out of a separation box built with stabilizer and curved surfaces and the air is diverted from the boundary r. and it is conducted through the separation box.

2. Method according to claim 1, characterized in that the air is sucked from the boundary r. 3. - Method according to claim 1, 2, characterized in that the air is conducted uniformly over the width of the track. 4. Method according to one of claims 1 to 3, characterized in that, additionally, the air is conveyed and separated from the underside of the paper track. 5. Method according to claim 4, characterized in that the air separated from the paper path is sucked. 6. - Procedure according to the claim 4, 5, characterized in that, after separation of the air charged with dust, ambient air is supplied to prevent the formation of eddies. 7. - Method according to one of claims 1 to 6, characterized in that the paper track is stabilized before air separation. 8. - Method according to claim 7, characterized in that the entrained air deviates from the stabilizer. 9. Device for separating the powder from a moving paper track, especially crepe paper, with a first separation box that runs transversally to the paper track, characterized in that, the first separation box is formed as a stabilizer with guide surfaces curves for the paper track and presents a device for the deviation of the air limit r to an accumulation channel of the separation box. 10. Device according to the claim 9, characterized in that, the accumulation channel has a cross section that widens towards the discharge side of the paper machine. 11. Device according to claim 9, characterized in that, on the running side of the paper 16 of the first separation box, a suction slot is provided, which is preferably made adjustable. 12. - Device according to one of claims 9 to 11, characterized in that the separation box is open wide. 13. - Device according to one of claims 9 to 12, characterized in that another separation box is provided on the lower side of the paper track on which runs the paper track with a very small angle preferably of the 5th , for example of the 2nd. Device according to claim 13, characterized in that the other or second separation box has a deflection plate that is preferably made incunable. 15. - Device according to one of claims 13, 14, characterized porcnae, the lower separation box is divided into at least two chambers. 16. Device according to one of claims 9 to 15, characterized in that a stabilizer is provided before the first separation box, which exerts a stretching effect across the paper track. 17. Device according to claim 16, characterized in that the stabilizer is incunable. 18. Device according to one of claims 9 to 17, characterized in that a suction hood in the form of a funnel is provided in the area of the scraper of the paper machine. 19. Device according to one of claims 9 to 18, characterized in that, a further separation box is provided on the upper side of the paper.