FI90503C - Procedure for repairing a roller to a paper machine - Google Patents

Description

90503

Method for repairing a paper machine roll Forfarande vid iståndsåttning av en Rolls till en pappersmaskin 5

The invention relates to a method for repairing a roll of a paper machine.

FI publication 71 508, EP publication 0 397 993, US patent publication 4 548 064 and EP publication 0 154 319 disclose the refurbishment of a paper machine roll by grinding. 10 Measurement during grinding is used for grinding control.

The rolls of the paper machine wear most strongly from the area of the web, leaving the outside of the web to carry. This is the case, for example, for press groove rollers, center rollers and calender rolls. The paper web is accompanied by abrasive particles and the roll wears hardest from the area of the paper web and from the edge of the roll outside the web the part carrying the roll remains on the roll, whereby the roll pressing becomes incomplete and inaccurate. Since the worst roll profile defect occurs at the edge of the track, the aforementioned wear defect is often the first reason why the roll should be removed from the press and re-ground.

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The invention has realized an improvement on the above-mentioned problem. In the invention, it is realized to grind the rollers forming the press nip from the edge areas with a separate grinding device.

Grinding is done from the side of the roller with the rollers in place on the machine. Grinding is done with either a wheeled or non-wheeled sanding stone / sanding belt. Said spacer 25 can be moved in a longitudinal direction of the roll to a suitable position. Roll radius control:; that is, the grinding depth is obtained, for example, by means of rollers, slippers or other similar control means adjacent to the grinding point.

The method according to the invention for repairing a paper machine roll is mainly characterized in that the method measures the roll surface wear from the roll edge area and when the edge error exceeds a certain maximum permissible error, removing said edge error by grinding the roll from the roll edge in the area in contact with the fabric passing through the paper web or the press nip, and that the method performs grinding of the press nip forming roll by means of a device arranged as standard on the roll edge area, thereby significantly

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.

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Figures 1A and IB illustrate a problem area of the invention. Figure 1A shows the ground rolls with the nip open.

Fig. 1B shows the rolls nip of Figs. 1A with the nip open at the stage when the track has worn the surface of the rolls and an off-track bearing area has formed on the edge areas of the rolls.

Figure 2 shows the measurement result from a roll that has elapsed after four months of use to the measured profile shape shown in the figure.

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Figure 3 shows a press roll assembly in which alternative grinding device arrangements at the edge areas of the roll are placed in connection with the press rolls.

Fig. 4A shows an arrangement of the grinding devices of the press roll, in which by means of a subframe 25 connected to the load arm, the grinding wheel can be rotated to a position in the edge area of the roll for performing edge grinding of the roll.

Figure 4B shows the Figure 4A apparatus 4A, the image seen in the direction of arrow D.

Figure 5 shows the position of the device according to the invention in different positions in the press section of the paper machine.

3 90503

Figure 1A shows an opened press nip formed by ground rolls. As used herein, a press nip refers to a nip formed by rolls of a paper machine, either groove rolls or smooth rolls, which may be located in a press or calender. As shown in the figure, the paper path W is between the felts Hj and H2. There may be only one blanket 5 (e.g., Hj) or no blankets at all, in which case the paper web is directly between the roll surfaces. As shown in Fig. 1A, the rollers Tt and T2 are ground and the pressing in the nip between the rollers takes place evenly over the entire width of the paper web W.

Fig. 1B shows the rolls of Fig. 1A at a stage where the surfaces of the rolls T1, T2 are worn from the area of the paper web W and a bearing area K1, K2 is formed on the rolls T1, K2 immediately outside the paper web W. The nip between the rollers TL, T2 is shown open.

Figure 2 shows an experimentally measured profile of the press roll along the entire length of the roll. As shown in the figure, a bearing region K is formed on the edges of the roll before the edge area E, where the roll surface has a shape error of about 0.25 mm and which represents the largest profile error along the entire length of the roll. The grinding of the roll is performed on the basis of said maximum error when the error exceeds a certain value. Thus, if the above-mentioned edge defect K can be eliminated e.g. by grinding the edge area E according to the invention, it is possible to considerably lengthen the grinding and maintenance interval of the entire roll.

Fig. 3 shows a press nip assembly formed by the rolls Τ1, Τ2, Τ3, Τ4 of a paper machine, in which the press nips NltN2 and N3 are passed through a wire-web combination R, ... whose configuration in different nips may be different. In the edge region of the rollers, due to the occurrence of 25 edge defects K, the edge protrusion K is removed by using the rotating grinding stone shown at 10 in Fig. 3 and / or the stationary grinding piece shown at 11. As shown in Fig. 3, in the lateral position of the roll Tj, there is a belt grinding device 12, the function of which is to eliminate the edge error K. The grinding is performed when the edge error K exceeds the maximum allowed value. Abrasives 10,11,12 are set / 30 can be set on both edge areas of the roll. The edge of the roll is ground to the profile level, 4 90503 which the rolls have in the area of the paper web W. In the arrangement, both or only one of the rollers forming the press nip N is ground.

Figure 4A shows a grinding device 13 mounted in the lateral position of the roll T. The grinding device 5 13 comprises a load arm 14 already inherent in the press and an actuator 15, preferably a cylinder device, articulated from the joint strip 16 and 17 so that the articulation point 16 The subframe 18 is articulated from the articulation point C to the load arm 14. A slider body 20 is placed in the guides 19 of the subframe 18, which comprises a grinding wheel 21 and a rotating motor 10 therein. has adjustable grinding depth.

Figure 4B shows the view of Figure 4A, Figure 4A viewed in the direction of arrow D. The slide frame 20 comprises a drive motor 22, the drive shaft 25 of the output shaft 24 of which engages the drive wheel 27 of the rotating shaft 26 of the grinding wheel 21. In connection with the slide frame 20 there are guides 23 on which the device can be supported on the grinding surface Tj. The guides 23 are preferably rotating rollers.

Figure 5 shows the press section of a paper machine. Figure 5 shows the position of the roll edge grinding device according to the invention at positions Aj, A2, A3. The grinding device is located as standard near the press nip in the edge area of the rollers to be ground, or the grinding device arrangement comprises coupling means in which the grinding device can be easily installed when performing edge grinding of the roll.

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Claims (1)

90503 Claim A method for repairing a roll (T) of a paper machine, which roll (T) is adapted to be stationary during use in the paper machine application and is adapted to form a press nip with the counter roll, and which method grinds the roll to reduce wear using abrasive grinding. 11 u in that the method measures the wear of the roll surface from the roll edge area and when the edge error (K) exceeds a certain maximum permissible error, removing said edge error (K) by grinding the roll (T) from the roll edge area to the profile level on the roll (T) is in the area 10 in contact with the fabric passing through the paper web or the press nip, and that the method comprises grinding the press nip forming roll with a device arrangement fitted as standard on the edge area of the roll (T), thereby considerably extending the edge defect (K) ) grinding the entire length profile LIAA and thereby reduce maintenance costs. 15 _______ - ττ. 6 90503 Forfarande for iståndsåttning av en Vals (T) i en pappersmaskin, vilken Vals (T) аr anordnad att under iståndsåttningen vara belågen pā plats i pappersmaskinen vid sitt 5 driftstalle ocar år anordnad att bilda ett pressnyp vid en mot slipar valsen for corrigation av slitaget och utnyttjar märtresultetet vid slipningen, kånnetecknat davar, att man vid forfarandet mater slitaget av valtytan iamminmin vid kantomradd av valsen och a kantfelet (K) overslider ett Givet tillåtet valsen (T) 10 pa kantområdet av valsen till en sådan profilnivå som valsen (T) har på det område som år i contact med vvnaden som Loper via pappersbanan eller pressnypet, och att man vid forfarandet utfor en slipning av valsen som bildar pressnypet med ett anord-ningsarrangemang som år anordnat som standardutrustning på kantområdet av valsen (T), varvid man i och med att detta kantfel (K) avlågsnas avsevårt forlånger slipmellan-15 rummet av hela långdprilen av valsen (T) och sålunda minskar servicekostnadema.