MXPA99003755A

MXPA99003755A - Method and device in a paper machine or equivalent or in a finishing device of same for removal of dust

Info

Publication number: MXPA99003755A
Application number: MXPA/A/1999/003755A
Authority: MX
Inventors: Lindstrom Jan; Leimu Juha
Original assignee: Valmet Corporation
Priority date: 1996-10-25
Filing date: 1999-04-22
Publication date: 2000-04-24

Abstract

The invention concerns a method in a paper machine or equivalent or in a finishing device of same for removal of dust, in which method a blowing (P) is directed at the web (W), which blowing separates dust from the web (W), and in which method a suction effect is applied to the web (W) for removal of the dust that is separated out of connection with the web. In the method, before the dust separating blowing (P) in the running direction of the web (W), a vortex flow (P2) is produced so as to prevent carriage of the dust into the environment and to compensate for the suction effect. Further, the invention concerns a device in a paper machine or equivalent or in a finishing device of same for removal of dust, in which device (10) there are blow elements (11, 13, 20) for producing a blowing (P) that separates dust from the web (W) and suction elements (14, 16, 15) for producing a suction effect so as to remove the dust that is separated out of connection with the web. The device (10) comprises an arrangement (20, 17, 18) for producing a vortex flow (P2) before the dust separation blowing (P) in the running direction of the web (W) so as to prevent carriage of the dust into the environment and to compensate for the suction effect.

Description

METHOD AND DEVICE IN A MACHINE TO MANUFACTURE PAPER OR EQUIVALENT, OR IN A DEVICE FOR FINISHING THE PAPER, FOR THE DISPOSAL OF DUST FIELD OF THE INVENTION The invention relates to a method, in a papermaking machine or the like, or in a finishing device, thereof, for the removal of dust, the method in which a blow is directed in the web of continuous paper, and this puff separates the powder from the web of continuous paper, and in the method a suction effect is applied to the web of continuous paper to remove the dust that is separated from the contact with the web of continuous paper. Furthermore, the invention concerns a device, in a papermaking machine, or equivalent, or in a finishing device, thereof, for removing dust, a device in which blowing elements are found to produce a blow that separates the powder from the web of continuous paper and suction elements to produce a suction effect in order to REF .: 30059 remove the dust that is separated from the contact with the web of continuous paper.

BACKGROUND OF THE INVENTION In the papermaking machines, on both sides of the web of continuous paper, which usually moves at a rather high speed, a boundary layer of air is formed, which transports together with it dust that has been separated from the mesh. fibers of the web of continuous paper and of the filling materials that are in the web of continuous paper. The dust is scattered in the environment and is also transported, partially, to the continuous paper reel. In addition, after papermaking, dust and contaminants, such as debris and fibers, adhere to the face of the web of continuous paper, and those contaminants come from the dryer section, the machine for the paper manufacture An important source of dust is the cutting process, in which abundant dust is separated from the continuous paper web when it is cut into component webs, in the longitudinal direction. In the production of silk paper, problems also occur with the powder, in particular in relation to the pleating by means of a scraper blade, where the web of continuous paper is separated by a scraping blade, from the face of a cylinder "yanki" heated with steam , in relation to which a particularly large amount of powder is separated from the web of continuous paper, and this powder is entrained by the web of continuous paper and spread to the environment. Dust and contaminants cause problems in the additional processing, for example in printing, because it is of vital importance, from the point of view of the quality of the printing, that the printing rollers remain clean. Also, the dust is spread both in the paper mill and in subsequent processes, to the environment, and the dust may involve health hazards at work, because it may contain several particles of recycled materials. With respect to the prior art, reference is made to U.S. Patent No. 3,239,863, in which a device for cleaning a web of continuous paper is described, in which a chamber space is used, in which formed by two air nozzles directed towards the web of continuous paper, the space between the nozzles is closed in such a way as to form an exhaust chamber for the air exiting the nozzles and for the dust separated from the web of continuous paper. In this arrangement or arrangement of the prior art one of the problems is how to produce a sufficiently high air blowing speed to separate the powder adhering to the web from continuous paper, as well as that the device has had to be constructed in a manner such that it is placed quite far from the web of continuous paper, in which case it is mainly suitable for the general removal of dust but not for detaching or separating the powder or contaminants from the web of continuous paper. A solution of the prior art, for the problems described above, is described in Applicant's Fl Patent No. 95,611, in which method and dust removal equipment it has been considered novel that the web of continuous paper has been subjected to a high pressure blow at in order to separate the powder therefrom and, in the direction of movement of the web of continuous paper, before and after blowing at high pressure, the powder and equivalent material that has been separated from the web of continuous paper is absorbed.

DESCRIPTION OF THE INVENTION The aim of the present invention is the further development of that solution, so that a more efficient and simpler solution is obtained, the manufacturing cost of which is also lower and which is also suitable for cleaning the continuous paper web, for both sides and across the entire width of the same. A further object of the invention is to suggest a solution in which there are no problems of ease of operation, for example, arising from the vacuum necessary to suck the powder, and through which it is possible to prevent access of the powder as a leakage flow. back to the web of continuous paper and to the environment. In order to achieve the objectives set forth above and those which will be mentioned later, the method according to the invention is mainly characterized in that, in the method, before the blow for the separation of the powder, in the direction of movement of the web of continuous paper, A vortex flow occurs to prevent the transport of dust to the environment and to compensate for the suction effect. Furthermore, the device according to the invention is mainly characterized in that the device comprises an arrangement or arrangement for producing a vortex flow before the blowing for the separation of the powder, in the direction of the movement of the continuous paper web, in order to prevent the transport of dust to the environment and to compensate for the suction effect. In the arrangement according to the invention, the face of the blowing device, which is positioned facing the continuous paper web, has a shape such that part of the cleaning jet is returned towards the slot of the nozzle, which, through the formed vortex, it is possible to control the vacuum in the space and therefore it is possible to avoid problems of the ease of operation caused by an excessively high vacuum. In the arrangement according to the invention, the suction chamber has a shape and dimensions such that the high speed cleaning jet has a sufficient time and space to return to the exhaust air duct, therefore access is excluded of the dust as a leakage flow back to the web of continuous paper and into the environment. The arrangement according to the invention is suitable for cleaning the web of continuous paper, on both sides, and also, if necessary, in particular when passing a web of continuous paper wider than normal, in view of that the cleaning of the edges of the web of continuous paper, through the device for the elimination of dust, the ends of the device may be provided with lateral blowing nozzles. In the arrangement according to the invention, the exhaust air duct preferably has a shape such that an intensive vortex is formed in the duct, whereby the duct remains clean and, in addition, the bottom of the pressure chamber has a Such that, with an appropriate speed of jet cleaning, the adherence of the powder to the faces found in the device is prevented. In the arrangement according to the invention, the slot of the blow nozzle has been designed so that this slot can be adjusted, in which case the intensity of the blow for dust separation can be easily regulated. The blowing device, according to the invention, has also been placed so that it can be tilted in the direction of movement of the web of continuous paper according to the arrival angle of the web of continuous paper and with the kind of paper which is handled, to obtain an optimal cleaning result. The device according to the invention preferably extends across the entire width of the machine and, if necessary, for example when placed on the spreader rolls after a cutter, can be bent to the desired shape, for example up to the shape of deflected rollers, and bending can be controlled, for example, by measuring the distance from the face of the web of continuous paper. In the following, the invention will be described in greater detail with reference to the figures found in the accompanying drawing, and it is assumed, however, that the invention is in no way confined strictly to the details of those illustrations. Figure 1 is a schematic view, in vertical section, in the machine direction, of a device according to the invention.

Figure 2 is a schematic illustration of a device according to the invention, in the direction of the width of the web of continuous paper.

The Figure is a schematic illustration of an arrangement or arrangement of the device according to the invention, on both sides of the web of continuous paper.

Figure 4 is a schematic illustration of a further exemplary embodiment of the face or side of the suction chamber, in a device according to the invention.

Figure 5 shows a second exemplary embodiment, additional, of the face or side of the suction chamber, in a device according to the invention.

In the exemplary embodiment, which is shown in Figure 1, the air is passed to the dust removal device 10 along the inlet air duct 11, from which the air is passed into the air chamber 13 blowing air and from this through the opening 20 of the nozzle, such as a jet of air P at high pressure, towards the web of continuous paper or equivalent W. The direction of movement of the web W is denoted by the arrow of reference S, and the air flow traveling together with the web, is denoted by the reference arrow Pl. The exhaust air chamber of the dust removal device 10 is denoted by reference number 14, and within from that chamber a vortex chamber 16 has been formed which produces a concentrated vortex, in the exhaust air chamber 14, and the vortex keeps the exhaust air chamber 14 clean. From this chamber the air is passed to the exhaust air duct 15. The dust removing device 10 is placed near the web W so that a space 25 is formed, in which a vortex air flow P2 is formed by the combined effect of the P blow for dust separation. on the face or side 17 of the bottom of the device, and the air flow Pl carried along with the web, by means of the vortex P2 the access of the powder is prevented as a leakage flow back together with the web and, from this way, towards the environment. The vortex P2 is formed by the puff P for the separation of the powder, by the flow of air Pl traveling together with the continuous web W, by means of the shape of the face or side 17 of the suction chamber 1 of the di s pos i ?? The pressure of the powder positioned in the direction of the web W, and by the dimensioning of the vortex space 25, for example, by regulating the distance of the diameter from the continuous band W. The powder is separated from the bulb with inua when a stream of concentrated air, a puff P for dust separation is blown from the opening 20 of the nozzle into a stream, and this jet penetrates through the C. pe limit and separate the dust particles from the face of the web. The separated powder is removed in the suction chamber 14 and the air containing the dust particles is passed through the cleaning, for example, in a wet separator. The blowing pressure, of the blow for dust removal, is from 2 kPa to 50 kPa, preferably from 15 kP.a to 35 kPa, for example, when the device for eliminating pol or according to the invention is used, to remove the dust of paper 1 is / car tul inas for printing. The blowing speed that is used in the puff P for the separation of the powder is from 50 to 400 meters per second, preferably from 50 to 300 meters per second. Of course, the values used depend on the resistance of the continuous paper web that is handled, that is to say the intensity of blowing that supports the continuous band and the intensity of blowing that is necessary to separate the powder from the face of the continuous band. Of course, when handling softer paper classes, lower values are used. The vacuum in the suction chamber 14 is 0.5 to 6 kPa, preferably 1 to 3 kPa, but, of course, the vacuum values that will be used in the suction chamber also depend on the kind of paper handled. The distance of the blowing device, from the face of the web, is from 1 to 40 mm, preferably from 2 to 10 mm. The slot 20 of the nozzle can preferably be adjusted in such a way that the intensity and direction of the puff P for dust separation can be adjusted by adjusting the opening 20 of the nozzle. If necessary, the device 10 for dust removal can also be tilted, which is indicated by the arrow R, in accordance with the angle of arrival of the web W and according to the class of the web W that is handle, in such a way that an optimal cleaning result is obtained. As shown in Figure 2, the dust removal device extends substantially across the full width of the web, and, if necessary, can be bent to the desired offset shape, for example, of the rollers. spreaders, after a cutter. The bending can be controlled, for example, by measurements of the distance E 'from the face of the web, and the regulating members 40 are controlled based on the results of the measurement and based on the control 50, so that the device 10 for dust removal is bent to the desired shape. For cleaning the edges of the web it is possible to provide the ends of the device 10 for dust removal, lateral blowing nozzles, from which the blow PS is blown. This arrangement is particularly advantageous when handling a web W wider than normal. In the exemplary embodiment shown in Figure 1, the vortex P2 has been produced in such a way that the face or side 17 of the device 10 for the removal of dust that is placed with orientation towards the web and that starts from the camera of suction 14, has first taken the convex form towards the web W, in the direction of arrival of the web, after which a linear portion that ends at the opening 20 of the nozzle follows. The vortex P2 can also be intensified by giving a curved shape to the face 18 of the device 10 for dust removal defining the inlet opening 21 of the air flow Pl which arrives together with the web W, as shown, for example , in Figure 1. The guide face 18 can also be formed in another way, and, for example, Figures 4 and 5 can be compared. In the figures, generally, the air flows passing in the device 10. for the elimination of dust, they are denoted with arrows. Figure 3 is a schematic illustration of an exemplary embodiment in which the dust removal devices 10 are placed on both sides of the web W. This preferably takes place in such a way that the blow openings 20 are placed in front of the other, in which case the vortex spaces 25, in which the vortex flow P2 is produced by the effect of the lower face 17 of the device 10 of the puff P for dust separation, and of the air flow P2, they are placed substantially one opposite the other. Figure 4 shows an exemplary embodiment of the shape of the lower face 17 of the air chamber 13 in the device 10 for dust removal, in order to produce a vortex in the space 25. In this exemplary embodiment, the underside 17 has a concave shape with respect to the face of the web W from the suction chamber 14 to the blow opening 20. In this exemplary embodiment, the guide face 18 defining the inlet opening 21 for the air flow Pi has been bent such that it has substantially an L-shape with respect to the direction of movement of the web W. Figure 5 shows a second exemplary embodiment for producing a vortex air flow P2 in space 20, and in this exemplary embodiment, the vortex flow P2 is produced, in addition by the blowing P for dust separation, the flow of air Pl traveling along with the web W, and the shape of the bottom face 17, also by a blow P3 through the opening 27 of the nozzle, blown P3 which is parallel to the lower face 17 and conforms to the direction of movement S of the continuous band and is of a direction substantially opposite to the direction of the blow P for the separation of dust. In this exemplary embodiment the lower face 17 is substantially linear, and the guide face 18 is curved but is bent towards the direction of arrival S of the continuous web W. The scope of the invention, of course also includes embodiments in which the Modes are connected with the guide faces 18 and / or with the lower faces 17 of different types and shapes. In the foregoing the invention has been described with reference to some preferred exemplifying embodiments thereof, only, however, it is assumed that the invention is in no way confined strictly to the details of those embodiments. For example, a vortex flow can be produced in several different ways, in addition to the exemplary embodiments illustrated in the figures, and from the point of view of the invention it is essential to produce this vortex flow to increase the dust removal efficiency of the device. and, at the same time, to control any void areas that may possibly impair the ease of operation. Many variations and modifications are possible within the scope of the inventive idea defined in the following patent claims. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention. Having described the invention as above, property is claimed as contained in the following:

Claims

1. A method in a papermaking machine, or equivalent, or in a finishing device, thereof, for the removal of dust, in the method a blow (P) is directed to the web (W), and the blow separates the powder from the web (W), and in the method a suction effect is applied to the web (W) for the removal of dust that is separated from contact with the web, the method is characterized in that, in the same, before the puff (P) to separate the powder, in the direction of the movement of the continuous band (W), a vortex flow (P2) is produced in order to prevent the transport of the dust to the environment and compensate for the effect of suction.

2. A method according to claim 1, characterized in that, in the method, the vortex air flow (P2) is produced by a combined effect of the blow for the separation of the powder (P), from the face or side (17) of the device for removing dust (10) placed in position facing the web (W) and the air flow (Pl) traveling together with the web.

3. A method according to claim 1 or 2, characterized in that, therein, the vortex flow (P2) is produced by a joint effect of the powder separation blow (P), of the face or side of the device for the removal of the powder (10) placed with orientation towards the continuous band (W), of the air flow (Pl) traveling together with the continuous band, and of an additional blow (P3) produced by the device for the elimination of dust ( 10).

4. A method according to any of the preceding claims, characterized in that, in it, the vortex flow (P2) occurs on both sides of the web (W).

5. A method according to any of the preceding claims, characterized in that, in the same, the distance of the device for the removal of dust (10) from the web (W) is regulated based on the measurements of the distance (E '). ).

6. A method according to any of the preceding claims, characterized in that, in the same, the device for dust removal (10) is inclined in the direction of movement of the web (W) based on the angle of arrival of the continuous band and based on the class of the continuous band that will be handled.

7. A device, in a papermaking machine, or equivalent, or in a finishing device, thereof, for the removal of dust, device in which there are blowing elements (11, 13, 20) to produce a blow ( P) which separates the powder from the web (W) and suction elements (14, 16, 15) to produce a suction effect in order to remove the dust that is separated from the contact of the web, the device is characterized because it comprises an arrangement or arrangement for producing a vortex flow (P2) before the blow for dust separation (P) in the direction of movement of the web (W) in order to prevent the transport of dust to the environment and compensate the effect of suction.

8. A device according to claim 7, characterized in that the arrangement or arrangement in the device for producing the vortex air flow (P2) comprises an opening of the nozzle to produce the blow (P) that separates the powder, a side or side of the device for dust removal is oriented towards the web, and a guide face (18) for directing the air flow (Pl) traveling together with the web.

9. A device according to claim 7 or 8, characterized in that the device further comprises an opening of the nozzle, to produce an additional blow (P3) before the opening of the nozzle of the blow (P) for the separation of dust in the direction of movement of the continuous band (W).

10. A device according to any of the preceding claims, characterized in that the device is formed as two units, placed on opposite sides of the web (W).

11. A device according to any of the preceding claims, characterized in that the device comprises an arrangement or arrangement for measuring the distance of the device (10) for dust removal, from the web (W) and to regulate the distance in based on the measurements (E ') of the distance.

12. A device according to any of the preceding claims, characterized in that it extends substantially over the entire width of the continuous band (). SUMMARY OF THE INVENTION The invention concerns a method, in a papermaking machine, or equivalent, or in a finishing device thereof, for the removal of dust, the method in which a blow (P) is directed to the web of continuous paper ( W), and the blow separates the powder from the web of continuous paper (W), and in the method a suction effect is applied to the web of continuous paper (W) for the removal of the dust that separates from the contact with the paper. band. In the method, before the blow (P) for the separation of the powder in the direction of the movement of the web of continuous paper (P), a vortex flow (P2) is produced in order to prevent the transport of the dust towards the environment and to compensate for the suction effect. Furthermore, the invention relates to a device, in a papermaking machine, or equivalent, or in a device for finishing thereof, for dust removal, device (10) in which there are blowing elements (11, 13, 20) to produce a breath (P) that separates the powder from the web of continuous paper (W) and the suction elements (14, 16, 15) to produce a suction effect in order to eliminate dust that is separated from contact with the paper web continuous. The device (10) comprises an arrangement or arrangement (20, 17, 18) to produce a vortex flow (P2) before the puff (P) for dust separation, in the direction of movement of the web of continuous paper (W). ) in order to prevent the transport of dust to the environment and to compensate for the suction effect.