FI114403B - Threading Procedure - Google Patents

Description

114403 Threading method

The present invention relates to a method for implementing a fiber web threading in a fiber web processing apparatus 5 incorporated in a paper / board machine, wherein the processing device has a belt rotation arranged around the guiding means and at least one non-belt , in which, when starting the threading, a narrow threading strip is cut from the fibrous web, which is applied to the threading means for carrying the threading to the processing device.

In order to introduce the fibrous web to be processed into various structural groups of the paper / board machine, such as formed, press, dryer, coating machine, calender, by means of an adjacent closing threading strap inside and through the assembly before spreading the fibrous web to its full track width. The function of the closure thread is known in the art and one solution ': 20 for opening and closing the closure thread to allow insertion of the threading strip I is disclosed in FI patent 55882. For the purposes of this application, the term "closure thread" includes e.g.

In addition to the closable filament strap disclosed in U.S. Patent No. 5,5882, endless filament arrangements with endless rope, chain or ribbon means are known per se, in which the filament strap is compressed between two or more rope, chain or ribbon members.

It is an object of the present invention to provide an improved method for carrying out threading in a threaded fiber web processing; ] On 30 devices. In order to accomplish this object, the method of the invention * * * * '] is characterized in that the method involves threading

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at the side of the roll, by guiding the strap rotation to the side for normal threading, while the strap is routed back to the normal driving position.

The method of the invention provides an easy and secure threading 5, since the threading does not have to be done through a closed processing area (belt-matching member nip) and the break sensitive threading strip does not have to be displaced laterally but the threading can take place directly from the edge of the web. The method further has the advantage that the sensitive belts are not at risk of being damaged due to paper molding, and the method does not require any new equipment but can utilize known belt rotation control devices.

The invention will now be described in more detail with reference to the accompanying drawings, in which: Figure 1 schematically illustrates a known metal belt calender in which the method of the invention can be applied; with the strap being offset from the normal running position for head restraint.

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The invention can be applied to a variety of strap-on head assemblies with strap rotation, such as threading to devices of the type of metal belt calender of Fig. 1 as disclosed in patent application FI20020159. The metal belt calender 1 of Fig. 1 includes a calender belt 2 made from a stable, which rotates about the guide rollers 3, ...: at least some of which guide rolls are movable to adjust the tension of the belt 2 to the desired. The calendering belt 2 passes around a roll: · ·: 5 arranged outside it, whereby a calendering zone is formed between the belt 2 and the roll 5. The 3 114403 lantern material web W passes through the calendering region, whereby it is subjected to the desired pressure pulse and thermal effect as a function of time. Fig. 1 also shows a nip roll 4 acting as a press member arranged inside the calendering belt 2, which presses against the roll 5 to form a high pressure 5 inside the calendering area of the nip (the shape of the pressure pulse when using the nip roll is shown in line 9). The dashed line 8 illustrates the shape of the pressure pulse when the contact pressure acting in the calendering area is formed solely by the tension of the belt 2. 6 denotes heating elements such as an induction heater, an infra-10 red radiator, a gas burner or a capacitive heater.

Figure 2 is a schematic top plan view of the position of the belt 2 of the device of Figure 1 in the normal driving position. For threading, the strap 2 is deflected from its normal driving position to the position shown in Figure 3 15 where the original position of the strap 2 is indicated by dotted lines. The threading strip Wi, cut from the edge of the web W, can then be passed through the surface of the guiding means 3 via the threading means (not shown) through the device 1 so that the threading strip can pass substantially along the edge of the web W. ··. following the normal route, avoiding the usual · ·. 20 lateral displacement of the tapping strip and any associated tearing of the tapping strip.

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The above invention has been described in more detail as applied to a metal belt calender. for threading but it is also suitable for threading in other groups of paper / board machine belt rotation, e.g.

• 1: formed, clamp, dryer, coating machine and belt calender.

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Claims (5)

A method of realizing web feed of a fiber web in a processing device (1) incorporated in a paper / board machine for a fiber web, the processing device having a web orbit (2) arranged around a control member (3) and at least one outside the web orbit. arranged abutment means (5) such that between the web orbit and the abutment means is formed the treatment region of the fiber web, through which the fiber web (W) to be treated is passed, in which method when starting the web feed, a narrow web feed strip (Wi) is cut by the fiber web. , which is conveyed to the web feeding means by which the web feed to the processing device is performed, characterized in that in the method the web feed is performed on the side of the web orbit by controlling the web orbit during the feed St side from the normal driving position and where the web feed is controlled. to normal driving position. 2. A method according to claim 1, characterized in that in the method the fiber web (W) is propagated to its full width before the web is guided back to its normal driving position. 20 Method according to claim 1, characterized in that in the method: the fiber web (W) is extended to its full width after the web has been guided back [: to its normal driving position. 25 4. A method according to claim 1, characterized in that in the method - the fiber web (W) is spread to its full width while the web is guided back *; * * to its normal driving position. I t «tl · Method according to any of the preceding claims, characterized in that, in the method, the web feed strip (Wi) is passed through the device as follows:. ': The surface of the regulating body (3).