FI105706B - Arrangements in connection with the heating device of the paper or cardboard machine web - Google Patents

Description

The invention relates to an arrangement of a paper or board machine 5 web heater having a heater arranged to heat the web by placing the heater in its working position. The heating device includes a heating surface which is facing the web during the manufacture of paper or board. The web may not need to run 10 horizontally at the heating point, but the web may also be inclined at this point ..._________

In a paper and board machine, web heating devices are used to heat the web to an optimum temperature for dewatering. The heaters are used particularly in the press section, but also elsewhere in the paper or board making line may be a heater. The most common heater is a steam box, but infra and high frequency heaters are also used. Generally, the heating device heats the web 20 in the transverse direction, either constant or profiled. Other directions of web heating are also used. In addition, heating may occur from the side or even from above.

When the web is heated substantially below the web, the paper heater tends to come to a surface on the surface of the web heater when a web is taken on a press section or the web is cut off. Removing a piece of paper from the top of the heater is difficult. This has been attempted with various water jets. However, for example, these feed the steam plate 30 extra water, which is difficult to remove.

'. It may also happen that steam flowing from the steam box causes water droplets to spill, making marks, holes in the web, or even causing the web to break.

The object of the present invention is to provide an arrangement by which. preventing the aforementioned problems with known heating devices. Characteristic features of the arrangement according to the invention are disclosed in the appended claims. The starting point of the invention is to prevent the paper shred from reaching the heating surface of the heater. This usually requires moving the heater from a working position to a protective space at a distance from the web. According to one of the 5 preferred embodiments, the heater is rotated about 90 ° to rotate the heater surface so that no paper shred is placed on it during the threading step. According to another embodiment, a special cover is used to cover the heating surface. The paper shred falls off the cover or the cover is cleaned with water or air jets after turning it off the heating surface.

Other advantages and embodiments of the invention will become apparent below in connection with the exemplary embodiments set forth below. 15 These are illustrated in the accompanying drawings, in which:

Figures 1a-Id show an embodiment of an arrangement according to the invention.

Figures 2a to 2d show another 20 embodiments of an arrangement according to the invention.

Figures 3a-3d show a third embodiment of an arrangement according to the invention.

Figures 4a-4c show a fourth embodiment of an arrangement according to the invention.

25

In the accompanying figures, all four embodiments are shown in the press section of a papermaking machine, which is the most common application for the arrangement of the invention. As such, the invention can be applied elsewhere in the paper or board manufacturing line. * · 30 In the pictures, functionally identical parts are identified by the same reference numerals.

With particular reference to Fig. 1, the heating device 1 is positioned below the press felt H above a blanket or suction box 7 which creates a vacuum. In the figures, the press section shows a section in which the web 3 105706 moves to the third press felt by means of pick-up rolls 4 and 6. The web is supported on the press felt by means of blow boxes -> or suction boxes 5 and 7.

»5 In Fig. 1a, the threading strap led to the press section is designated by the letter W. In the threading step of the web, the paper shred and the ribbon pass down and over the heater. During the threading phase, the heating device 1 is pulled down by a suitable transfer device (not shown) and protected by a shield 3. The transfer device provides at least a sufficient displacement which allows the shield 3 to be positioned and pivoted on and back of the heating surface 2.

In Fig. 1a, the heater is shown protected so that the cap 3 is on the heater surface 2 of the heater 1 and any paper shred of threading step falls on it. The cover 3 is hinged to the body of the clamping member by means of a fixed joint 9.

In Figure Ib, the threading is successfully completed and the actual continuous web W passes through the press portion, whereby the cover 3 can be pivoted off the heating surface 2 and the heating device raised at a suitable distance from the web as shown in Figure 1b. At the same time, as shown in FIG. These are used to inject water into the tilted cover 3, causing the paper shred to drain down. As shown in Fig. Id, other jet means 8b, which are located at the top of the screen, can be used, with a downward jet dropping * · 30 over the paper shield screen 3. In the embodiment of Fig. Le, it is necessary to be careful not to spray water into the web W so that it is not cut off or its quality otherwise impaired.

The spraying means may also operate on compressed air.

. · 35 4 105706

2a-2d, the arrangement is placed in a space 9 similar to the one above. Here again, the heating device 1 is provided with a transfer device for transferring it from the operating position to the protective mode and vice versa. Here, the heater 1 comprises a cover 3, similar to a lid 5, which is pivoted at its upper edge. According to Fig. 2b, after use of the cover, it is turned about 180 ° in the direction of travel of the web, whereby it can be safely cleaned from below by the spray means 8a and the heating device can be lifted onto the web W as shown in Fig.

10

Again, as shown in Figure 2d, the jet means 8b can be attached to the edge of the cover. The embodiment according to Figures 2a to 2d is disadvantageous in that it requires extra space in the direction of web travel.

15

The embodiment according to Figures 3a-3d can accommodate a narrower space if necessary. Here, the heating device 1 is moved to the protective space in the same manner as above, but here the heating device 1 is pivoted about 90 ° 20 with suitable turning devices (not shown), whereby the heating surface 2 is pivoted away from the web.

The other sides of the heating device 1 form a functional shield 3 'which collects the paper shred and the strips in the threading step as shown in Figure 3a. These can be washed as shown in Fig. 3b by the spray device 8 when the heating device 25 is turned back to the correct position by the spray device 8a. Finally, the heater is moved back to its working position as shown in Figure 3c.

In this embodiment as well, as shown in Fig. 3d, spray means 8b, which are attached to the heater itself, can be used to clean the functional shield 3 ', i.e. the side of the heater.

Figures 4a-4d show an automation with which the cover 3 is engaged. 35 can be turned over on the heater when it is moved from the working position to the shield. Here, the shield 3 is hinged to the paper machine by means of a joint 9 5 105706 and includes a shank 10 rigidly secured to the shield 3. This shank 10 is operated by a stop 11 on the heating device 1. The shelf 11 and shank 10 are arranged to rotate the shield 3 2 on * 5 le in protection mode. As shown in Fig. 4b, when the heating device 1 is raised, the stop 11 actuates the handle 10, whereby the cover 3 turns away from the heating surface 2. The cover 3 can then be washed with the spray means 8a as above and the heater (Fig. 4c) activated.

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Claims (8)

6 105706 An arrangement in connection with a paper or board machine web heating device (1), wherein the heater device (1) is arranged to heat the web (W) by positioning the heater device (1) in its working position close to the web (W), and wherein the heater device (1) 2) facing the web (W) during the manufacture of paper or cardboard, characterized in that the arrangement includes means (3) for keeping the heating surface (2) wet from the paper shred, if necessary, for example during the threading step of the web. Arrangement according to Claim 1, characterized in that the arrangement comprises a transfer device for the heating device (1) for moving it 15 away from the working position from the web (W) to the protective space. Arrangement according to Claim 2, characterized in that the arrangement comprises a pivoting means of the heating device (1) for pivoting the heating surface (2) away from the web (W) while the other sides functionally form the cover (3 ') of the heating surface (2). Arrangement according to Claim 2, characterized in that the arrangement comprises a cover (3) pivotable on the joint (9) and a pivoting device, which cover (3) is arranged to pivotally protect the heating surface (2) in the protective space. . Arrangement according to Claim 3 or 4, characterized in that the arrangement comprises water and / or air jets (8a, 8b) for cleaning the cover (3, 3 '). Arrangement according to Claim 5, characterized in that the spray devices (8a, 8b) are arranged such that they purge the cover (3, 3 ') when it is turned away from the heating surface (2). ..7 105706 Arrangement according to Claim 4, characterized in that the pivoting means of the shield comprises a pivoting arm (10) attached to the shield (3) and a stop (11) attached to the heating device (1) adapted to actuate the shield (3) ) when moving the heater from a working position to a protective position and back, Arrangement according to Claim 2, characterized in that the transfer of the shield (3) to the protective state of the heating device (1) and back to the operating state of the heating device is arranged to be carried out by the transfer movement of the heating device (1). * <«W ·« •. -. . 8 1CE7G6