FI88060B - Device for the cutting off the threading strip of a paper web - Google Patents

Abstract

The invention relates to a device for cutting and inclined drawing of the threading strip of a paper web R. In the device the paper web R is cut by directing a jet S of medium from a cutting nozzle 13 against the paper web R. In the device according to the solution the cutting nozzle 13 is placed in contact with the web W that is to be cut in conjunction with the roll surface 10'. The jet S of medium is directed from the cutting nozzle 13 against the web R and via this over the zone surface 10a of the roll/cylinder surface 10', which surface 10a is made more wear-resistant than the rest of the roll/cylinder surface. <IMAGE>

Description

88060

Arrangement of equipment in the cutting of a paper web headband Anordningsarrangemang vid skäming av spetsdragningsbandet av en pappersbana 5

The invention relates to an arrangement of devices for cutting a paper web headband.

Several different so-called bevel pullers arranged on the drying section of the paper machine, in particular at the end of the drying section. In the known oblique drawing devices, a spike attached to a mechanical traverse, which acts against the drying cylinder and with which the oblique drawing is performed, is used as the cutting part of the web. The disadvantage of this device is that the spike scratches the cylinder and becomes dull quickly, thus deteriorating the cut.

15

It is also previously known to use a circular-like device placed in the traversing carriage as an oblique traction device or to perform oblique traction manually, e.g. with a knife.

It is also known to use a pressurized water jet to cut a paper web. The water jet 20 is adapted to cut the paper web against the roll surface. During cutting of the paper web, the cutting jet is applied to the same point on the roll surface for a long time. High pressure water causes wear on the roll surface.

This application discloses a device solution which avoids the above-mentioned wear of the roll 25.

In order to prevent wear of the cylinder / roll, the cylinder / roll is provided at a certain point with a separate surface area that is more resistant to wear than the rest of the cylinder surface.

According to the invention, a medium jet (S), e.g. a water jet, is used as the web cutting member, which is directed to the web surface in a position where the web is located against a cylinder or 2 88060 rolls. The medium jet (S) meets the web surface and then the cylinder or roll surface.

In the device arrangement according to the invention, the surface of the cylinder or roll is formed from the impact area of the medium jet more wear-resistant than the other surface of the cylinder / roll. Said surface is formed e.g. by spraying the collected on the area of the surface of the cylinder / roll to which the medium jet is directed. The wear-resistant surface can also be obtained by hard chrome plating or hard welding, e.g. stellite welding. The surface can also be hardened from a certain area by heating, e.g. by induction heating. This is possible if the material of the roll / cylinder is, for example, gray cast iron or spheroidal graphite cast iron.

In the method and device arrangement according to the invention, the headband is cut against the rotated roller / cylinder surface. During cutting, the paper web is well supported against the cylinder surface / roll surface and no other separate abutment surfaces are required. The cylinder / roll surface also acts as a conveyor for the paper web and headband. The support of the paper web at the cutting station is good. Since the cutting surface is a cylindrical surface, the distance is always constant. The medium jet (S) can thus be precisely aligned at the optimum angle and at the correct k <x>, e.g. in droplet size, on the paper web.

20

The device arrangement according to the invention for cutting the paper web headband is mainly characterized in that a jet of medium is applied from the cutting nozzle to the web and through it to the roll / cylinder surface on a zone surface which is made more resistant to wear than the other roll / cylinder surface.

25

The invention will now be described with reference to some preferred embodiments of the invention shown in the figures of the accompanying drawings, to which, however, the invention is not intended to be exclusively limited.

Figure 1 shows a cutting operation of a headband according to the invention in connection with a cylinder / roll. The presentation is principled.

I: 3 88060

Figure 2 shows a shear arrangement of a headband in a drying cylinder array of a paper web finishing machine.

Figure 3 shows the arrangement of the device according to the invention and the arrangement 5 of the bevel cutter in the two-wire region of the drying cylinders in connection with the lower cylinder in position A2.

Figure 4 shows an arrangement of devices according to the invention in a drying cylinder group of a paper web finishing machine in connection with the upper cylinders in positions A3 and A4 and in connection with the lower cylinder in position A5.

10

Figure 1 illustrates a cutting operation of a paper web headband Rt according to the invention. A beam 11 is placed at a distance of the width L of the cylinder / roll at a certain distance from the roll surface, along the guides of which the cutting device 12 of the paper web R is moved, from the cutting nozzle 13 a jet of medium S is applied to the surface of the paper web 15. Preferably water is used as the medium. The water pressure is 1000-1500 bar. The cutting nozzle 13 is kept at a small constant distance from the surface 10 'of the cylinder / roll 10. The cylinder / roll surface 10 'is provided with a width travel Lj on a more wear-resistant surface than the other roll surface, and said surface area 10a, the zone surface, is located near the cutting nozzle 13 in the area of the roll surface 10' where the medium jet 20 falls.

The headband Rt is further passed through a paper web surface treatment line or other similar web treatment line or passed directly to a winder and a portion of the web R2 is passed to a wreck. The cutting nozzle 13 is guided in the beam 11 by means of a guide device 14 so that when the web R is spread again, the cutting nozzle 13 is moved by the guide device 14 in the beam 11 in the transverse direction (direction D]) (direction D2). However, during the head removal, the cutting nozzle 13 is in position C in the edge region of the cylinder / roll. If the roll surface 10 'is not separately surface treated from the area 10a to withstand the pressure of the medium jet S, the intermediate jet S 30 would rapidly consume a groove in the roll surface 10'. According to the invention, the roll 10 is provided with a surface 10 'in the area 10a, i.e. from the area where the medium jet S hits the roll surface, with a surface layer more resistant to 4,88060 or heat-treated said area 10a. This gives an area 10 'on the roll surface which can withstand the surface load caused by the medium jet S.

In this application, when referring to the medium jet S, the medium most preferably means pressurized water. The medium of the medium jet S can also be pressurized air or the medium jet S can be formed by a laser beam.

The wear-resistant surface area 10a of the roll 10 can also be provided e.g. by spraying-10a collected on the roll surface 10 'in the width area L1. The injected ceramic may be an oxide ceramic, e.g. Zr, Al, Si, Ti, Y, Cr oxide, or a carbide ceramic, e.g. Cr, W, Ti, Nb carbide or boride, e.g. Fe , Cr, Ti boride or a mixture or compound thereof. Among the above-mentioned ceramics, metals, e.g. Al, Cr, Ni, Co, may be doped. Em. under the ceramic or cermet coating, one or more so-called adhesive layers can also be used against the frame to ensure good adhesion of the ceramic or cermet layer. The adhesive layer is preferably a thin, thermally sprayed, minimally porous metal layer. The thickness of the ceramic or cermet coating is 0.05-4 mm, most preferably 0.5-2 mm.

A wear-resistant surface can also be provided in the area 10a by hard-chroming the surface 10 'from the area 10a. The wear-resistant surface can also be obtained by brazing, e.g. by stellite welding.

The surface area 10a can also be heated and hardened by induction. In this case, the material of the roll / cylinder 25 is hardened, for example gray iron or spheroidal graphite cast iron.

Figure 2 shows an arrangement of devices according to the invention in a drying cylinder group of a paper web finishing machine in the area of a two-wire outlet. The paper web R is passed from the drying cylinder K1 to the drying cylinder K2 above and from the drying cylinder K2 30 to the drying cylinder K3 below and from the drying cylinder K3 to the drying cylinder K4 above and onwards to the calender F. The upper wire Hj 5 through the wire guide rollers C4 and C5 and the drying cylinders K! and K3 along the surface. The paper web R is cut at position Aj near the surface 10 'of the drying cylinder K3 before the point Ej of the junction of the wire H2 and the web R. The cutting nozzle 13 is located in position A, at a distance from the cylinder surface 10 ', and the cutting strip Rt is passed through the entire line after cutting. Once the headband has been obtained through the line, the cutting nozzle 13 can be moved in the width direction of the web (direction D1 # in Fig. 1), whereby the web is spread to a normal width. The figure shows fan boxes for supporting the export of the headband 10 through the line. The fan boxes are indicated by the letters G1, G2, G3, G4, G5, G6, G7 and

gs ·

FIG.

Figure 4 shows the arrangement of the cutting nozzles 13 in the positions A3, A4 and A5 of the drying cylinder group K2, K3, K4. As shown in Fig. 4, the cutting nozzle 12 is located in position A3 20 on the cylinder K2 of the web R in the inlet region before the junction E1 of the wire H and the web R.

A4 cutting nozzle is located at position 13 of the drying cylinder K3 the web running direction with respect to the downstream region. The cutting nozzle cuts the wire H and the surface 10 'of the drying cylinder K3, the wire H being located in said position A4 against the cylinder surface 10' 25 and the web R being outer.

The figure further shows the cutting nozzle 12 in position A5 in connection with the drying cylinder K4 above. In said position A5, the wire H is led away from the web R by means of the wire guide rollers Nj and N2 before the web comes to the cylinder K4 so that the web can be cut against the cylindrical surface 10 'alone with the wire H being led out of the web Wire H and web R

6 88060 merge at point E4. Thus, in said icing arrangement, a free space is formed between the web R and the wire H, in which the cutting arrangement 11,12,13 of the paper web is placed.

Claims (9)

Apparatus solution for cutting and skewing the tip drawing tape of a paper web (R), in which device solution the paper web (R) is cut by directing a medium jet (S) from a cutting nozzle (13) to the paper web (R) and in which device solution (cutting) 13) is placed in contact with the web (W) to be cut and is in connection with the rolling surface (10 '), characterized in that the medium jet (S) is directed from the cutting nozzle (13) towards the web (R) and via this over the surface ( 10a) of the roller / cylinder surface (10 '), which surface (10a) is made more durable than the other roller / cylinder surface. Device solution according to the preceding claim, characterized in that the durable surface (10a) is a ceramic surface (10 '). Device solution according to the preceding claim, characterized in that the ceramic is oxide ceramic, advantageously Zr, AI, Si, Ti, Y, Ti-boride or a mixture or compound thereof. Device solution according to claim 1, characterized in that the wear-resistant surface (10a) is a surface of hardened chrome. Device solution according to claim 1, characterized in that the wear-resistant surface (10a) is a hardening weld, advantageously a frame surface. Device solution according to claim 1, characterized in that the wear-resistant surface (10a) is a hardened surface. Device solution according to any of the preceding claims, characterized in that the medium in the medium stream (S) is pressurized water. - 30 10 88060 Device solution according to any of the preceding claims 1-6, characterized in that the medium in the medium stream (S) is pressurized air. Device solution according to any of the preceding claims 1-6, characterized in that the medium in the medium stream (S) is laser light. IN: