GB2081663A - Method of replacing dryer felts on papermakers machines - Google Patents

Abstract

A method is disclosed for replacing dryer felts which are mounted in the dryer section of a papermakers machine. The method comprises the use of a coupling component (32) which is attached to the trail end of the felt (10) to be replaced and the lead end of the replacement felt (22). The new felt (22) is drawn into position by traction of the old felt (10). The method is advantageous in that it obviates damage to the old felt, which may be rehabilitated and reused. <IMAGE>

Description

SPECIFICATION Method of replacing dryer felts on papermakers machines The invention relates to papermakers machine clothing and more particularly relates to methods of replacing such clothing including seamed endless dryer felts on the machines.

Prior hereto, the conventional procedure employed to replace dryer felts, particularly monofilament, monofilament/multifilament and spun fabric dryer felts, required cutting the old felt in several places. This of course damaged the old felt and was in many instances undesirable, precluding a rehabilitation and ultimate reuse of the old felt.

By a method of the invention, dryer felts may be replaced on papermarkers machines in a faster simpler manner and if desired without damaging the structure of the felt undergoing replacement.

This saves the replaced felt for rehabilitation and possible reuse.

The invention comprises a method of replacing a seamed endless dryer felt mounted on a papermakers machine and supported thereon by guide rollers, said felt comprising a fabric web having a first end and a second end, said ends being joined by a removable seam to make the felt endless, which comprises:: removing said seam whereby the first and second ends are disengaged each from the other; providing a coupling leader which comprises a fabric structure having a leading edge adapted to mate with and engage with the seam-half of one of the first and second ends of the felt and a trailing edge opposite to the leading edge, adapted to mate with and engage with the seamhalf of the new felt described below; engaging the leading edge of the coupling leader with the seam-half of the first unseamed end; securing the trailing edge of the coupling leader to the third end of a new felt for replacement of the mounted felt, said new flat having a free fourth end; moving the mounted felt over the guide rollers in a direction toward the second end whereby the new felt is pulled over the support rollers and assumes the position of the unseamed mounted felt on the papermakers felt;; disengaging the coupling leader from the new felt; and seaming the third and fourth ends of the new felt together whereby the new felt is mounted and seamed to be endless on the papermakers machine.

The method of the invention is advantageous in that it minimizes damage to the felt under replacement.

By way of example, an embodiment of the invention will now be described with reference to the accompanying drawings, of which: Fig. 1 is a schematic representation of a typical dryer section in a conventional papermakers machine, showing the replacement of an old, seamed endless dryer felt with a new felt.

Fig. 2 is an isometric view of a part of the end of a new dryer felt coupled to the end of an old felt being replaced on a papermakers machine, by the prior art technique.

Fig. 3 is a top view of the end of an old dryer felt, the end of a new dryer felt to replace the old felt on a papermakers machine and the coupling means according to a method embodying the invention.

Fig. 4 is an enlarged view of a portion of the coupling means shown in Fig. 3.

Fig. 5 is an enlarged view of a part of the coupling means of Fig. 3, shown coupled to the end of the old felt being replaced.

The prior art is replete with descriptions of fabrics useful as seamed endless belts in the dryer sections of papermakers machines. In general, such fabrics include a woven structure of weft and warp yarns. The yarns may be composed of monofilaments or multifilaments or may be spun from staple fibers. The fabrics may be made in simple, mono-layer weaves or they may be complex, multilayer weaves depending on the particular properties required. A method embodying the invention may be employed to replace any known dryer felt, in the dryer section of a papermakers machine.

Fig. 1 is a schematic representation of the dryer section of a papermakers machine and includes a plurality of support or guide rollers 12 arranged with a plurality of steam or heating cans 14. The rollers 12 and cans 14 are driven or carried in the direction indicated by the arrows as a seamed endless dryer felt 10 passes in the direction indicated by arrows over the cans 14 while supported and/or guided on the rollers 1 2. As shown in the Fig. 1, the seamed endless dryer felt 10 is about to be replaced by a new felt 22. This is accomplished by unseaming the ends 16, 18 of felt 10 (the seamed ends 1 6, 18 make felt 10 endless) and coupling the trailing end 18 to the lead end of new felt 22 through an intermediate coupling device 20.The lead end 16 of felt 10 is then tracted to pull the old felt 10 through the dryer section of the papermakers machine and off the rollers 12 and cans 14. Simultaneously, the new felt 22 is pulled into the dryer section onto the guide rollers 12 and cans 14 to replace the old felt 10 and mount in the dryer section. The free ends of the new felt 22 are then seamed to make an endless dryer felt in the dryer section, after disengaging the coupling device 20 from the lead end of the dryer felt 22.

Fig. 2 is an isometric view of a part of the leading edge of the new replacement felt 22, engaged with the trail end of the coupling device 20 through a pin seam 24. The coupling device 20 is in fact a leader having attached a plurality of ropes 28, spaced evenly across its width. The ropes 28 are secured to the trail end 1 8 of the old felt 10 through slits 26 cut into the end 1 8 of felt 10. The making of the slits 26 in the fabric of felt 10 to secure the felt 10 to the ropes 28 is in fact the prior art procedure, which results in physical damage to the old felt 10. If the replaced felt 10 was otherwise reusable after cleaning, etc., these damages require repair before the felt can ever be reused.

Referring now to Fig. 3, one may see a top view of the end 18 of the old dryer felt 10 and the leading edge of the replacement felt 22. By one method of the present invention, the end 18 of the old felt 10 need not be cut to accommodate the ropes 28 of coupling leader 32. Instead the loops 30 of felt 10 are pressed through the space between yarns 36 of zone 38 and a pin is inserted through the loops to establish the couple. The couple between felt 22 and coupling leader 32 is similarly fashioned. By another method used where the old felt may be discarded, slits are made in the old felt and the ropes are used to secure the union but the connection of the coupling leader to the new felt is as described above.

The coupling leader 32 may be a short length of dryer felt fabric woven in the conventional manner from a plurality of filter (cross-machine direction) and weft (machine direction) yarns. Along the lead and trail edges, parallel to the cross-machine direction of the fabric, is a zone 38 wherein a plurality of filler yarns have been removed, leaving machine direction yarns 36 which serve as a means for joining the coupling leader 32 to the seam-half or loops 30 and 40 respectively of the felts 10 and 22. The Fig. 4, an enlarged view of the zone 38 shows the remaining machine direction yarns 36 after removal of associated filler yarns.

A coupling leader may also be constructed by sewing pieces of webbing, which contain a zone having filler yarns removed, to each end of any piece of fabric. In this way any piece of fabric available may be easily made into a coupling leader by sewing the webbing across the fabric on each end.

Referring now to Fig. 5, one may see how the coupling leader 32 lead edge is joined to the trailing end 18 of the old felt 10. The zone 38 of coupling leader 32 is pressed over the loops 30 which constitute the seam-half of felt 10. The loops 30 interengage with the yarns 36 in zone 38 and a pin is inserted to provide sufficient joinder of the coupling leader 32 to felt 10 so that a direct horizontal pull along the axis of the felt 10 will not rupture the joinder. The joined felts 12, 22 may then be pulled through the papermaking machine as described above. In this way, the old dryer felt 10 is not damaged and after its removal from the papermakers machine it may be disengaged from the coupling leader 32 by removing the pin engaging the loops 30 from the coupling leader 32.

The coupling leader 32 may be discarded after its use or can be retained for reuse a number of times.

Claims (4)

1. A method of replacing a seamed endless dryer felt mounted on a papermakers machine and supported thereon by guide rollers, said felt comprising a fabric web having a first end and a second end, said ends being joined by a removable seam to make the felt endless, which comprises: removing said seam whereby the first and second ends are disengaged each from the other; providing a coupling leader which comprises a fabric sheet having a leading edge adapted to mate with and engage with the seam half of one of the first and second ends of the felt, and a - trailing edge opposite to the leading edge, - adapted to mate with and engage with the seamhalf of the new felt described below; engaging the leading edge of the coupling leader with the seam-half of the first unseamed end;; securing the trailing edge of the coupling leader to the third end of a new felt for replacement of the mounted felt, said new felt having a free fourth end; moving the mounted felt over the guide rollers in a direction toward the second end whereby the new felt is pulled over the support rollers and assumes the position of the unseamed mounted felt on the papermakers felt; disengaging the coupling leader from the new felt; and seaming the third and fourth ends of the new felt together whereby the new felt is mounted and endless on the papermakers machine.

2. A method of replacing a seamed endless dryer felt mounted on a papermakers machine and supported thereon by guide rollers, said felt comprising a fabric web having its ends joined by a removable seam, the method comprising: removing said seam of an old felt whereby the seamed ends are disengaged each from the other, providing a coupling leader which comprises a fabric sheet, engaging the leading edge of the coupling leader with the seam-half of the trailing unseamed end of the web of the old felt, without irrevocably; damaging the old felt, engaging the trailing edge of the coupling leader with a seam-half of a leading end of a new felt, moving the old felt over the guide rollers to pull the new felt into position, disengaging the coupling leader from the new felt, seaming the ends of the new felt together.

3. A method as claimed in claim 2 further including the step of disengaging the coupling leader from the old felt without damage to the old felt.

4. A method of replacing a seamed endless dryer felt mounted on a papermakers machine and supported thereon by guide rollers, the method being substantially as herein described with reference to and as illustrated by Figs. 1,3, 4, and 5 of the accompanying drawings.