METHOD AND MEANS FOR RENEWAL OF THE INNER FACE OF THE ROLL MANTLE OF A SUCTION ROLL OF A PAPER MACHINE AND EQUIPMENT USED IN THE METHOD

Abstract: The invention concerns a method for renewal of the inner face of the roll mantle of a suction roll. The suction box (12) of the suction roll is provided with at least one grinding rib (20 and/or 21) and/or with means (17′,18′,19′) for the supply of grinding material, by means of which the inner face (11′) of the roll mantle (11) is renewed by grinding while rotating the roll mantle (11). The invention also concerns the equipment used in the method.

Description: The invention concerns a method for renewal of the inner face of the roll mantle of a suction roll of a paper machine as well as an equipment used in the method. From time to time, the inner faces of the mantles of suction rolls require surface processing as the seals placed at the contact points between the suction box of the suction roll and the roll mantle abrade the inner face of the mantle during operation. In a paper mill, said reconditioning and regrinding of the mantle has required detaching of the mantle portion of the suction roll from the suction box and transportation of said suction roll to be reconditioned out of the paper mill for separate machining. The transfer of heavy rolls for regrinding of the inner faces has involved high transfer cost, and the machining of the inner face of the roll has also been a time-consuming and costly operation. The object of the invention is a method for renewal of the inner face of a suction roll of a paper machine, in which method it has been possible to renew the inner face at the paper mill itself and by means of constructively simple arrangements of equipment. According to the invention, it has been realized that the inner face of the suction roll can be ground by making use of existing arrangements of equipment already present at the paper mill and existing arrange­ ments of equipment present at the suction roll. The method in accordance with the invention is mainly characterized in that the suction box of the suction roll is provided with at least one grinding rib and/or with means for the supply of grinding material, by means of which the inner face of the roll mantle is renewed by grinding while rotating the roll mantle. The equipment in accordance with the invention for renewal of the inner face of a suction roll is mainly characterized in that the equipment comprises at least one grinding rib grinding the inner face of the mantle of the suction roll and to be fitted in the suction box of the suction roll of the paper machine. According to the invention, it has been realized to use the seal sockets for the axial seals of the suction box in a suction roll as fastening means for separate grinding ribs. Further, according to the invention, it has been realized to make use of the equipment of posi­ tioning of the end seals for accomplishing a back-and-forth movement of the grinding ribs. Such an embodiment of the invention is also possible wherein grinding material is passed through the pressure medium ducts onto the face to be ground. Thereat, such an embodiment of the inven­ tion is possible wherein the grinding material is passed directly onto the axial seals, said seals being used for the grinding together with the grinding material. In the following, the invention will be de­ scribed with reference to some preferred embodiments of the invention illustrated in the figures in the accompany­ ing drawings, the invention being, however, not supposed to be confined to said embodiments alone. Figure 1 is an axonometric and partial illustra­ tion of a prior-art suction roll. Figure 2 illustrates the removal of the mantle part of the suction roll from around the suction box, and the figure shows the removal of the axial seals by means of arrows and the fitting of grinding ribs in accordance with the invention in place of the axial seals by means of dashed lines. Figure 3A shows an equipment in accordance with the invention as fitted in a conventional suction-roll construction. The illustration is a partial view of the suction roll and a sectional view taken along the longi­ tudinal axis of the suction roll. Figure 3B is a sectional view of the suction roll shown in Fig. 3A, taken along the section line B-B in Fig. 3A. Fig. 1 is an axonometric view of a conventional suction roll 10. The suction roll 10 comprises a roll mantle 11, and a suction box 12 inside the roll mantle. The suction box 12 defines a suction space 13 in its interior, and said suction space 13 can be subjected to negative pressure so as to produce suction into the space defined by the suction box in its interior and to suck liquid out of the paper web. The upper longitudinal edges 14a and 14b of the suction box 12 are provided with sealing means 15 and 16, i.e. with axial seals. The sealing means 15 and 16 are fitted in seal sockets 15a and 16a provided for the sealing means. In view of lowering the friction between the seals 15,16 and the inner face 11′ of the roll mantle 11, liquid is sprayed through inlet pipes 17,18,19 into the spaces of the sockets 15a and 16a defined by the seals 15 and 16, out of which said spaces the liquid is carried further along the seal faces to lubricate the contact faces between the seals and the mantle. In the way shown in Fig. 2, the suction box of the suction roll is provided with separate grinding ribs or equivalent which can be positioned. In the way shown in Fig. 2, the roll mantle 11 of the suction roll is removed from around the suction box 12, and the upper edges of the suction box 12 are provided with grinding ribs 20 and 21. Thereat, the axial seals 15 and 16 are removed and grinding ribs 20 and 21 are placed,in accordance with the invention, into the places of the seals into their seal sockets 15a and 16a, as is illustrated by the dashed lines. Figures 3A and 3B give a more detailed illus­ tration of the construction of a suction roll in accord­ ance with the invention. According to the invention, it has been realized to use the conventional liquid lubrica­ tion system fitted in connection with the seals 15 and 16 for passing the grinding fluid or grinding material to the point to be ground. Thus, the pressure-medium supply ducts 17,18 and 19 shown in Fig. 1 have been con­ verted to grinding-fluid supply ducts 17′,18′ and 19′. According to the invention, it has also been realized to accomplish an arrangement for displacing the grinding ribs in the direction of the longitudinal axis of the cylinder partly by means of existing constructions of equipment. Thereat, the adjustment-rod mechanism for the end seals is utilized for displacing the grinding ribs. The arms 24 and 25 related to the adjustment rods 22 and 23 are connected to an intermediate rod 28. The arms 24 and 25 obtain their control from the slide opening 27 in the support plate 26, to which said slide opening 27 the guide parts 24′ and 25′ for the arms 24 and 25 are coupled. The intermediate rod 28 is further connected to the grinding ribs 20 and 21. Thus, by displacing the adjustment rods 22 and 23, the grinding ribs 20 and 21 are also displaced. The grinding ribs 20 and 21 are fitted to move in their sockets 15a and 16a. The adjustment rods are passed out through the end plate, and, outside the end plate, they may be con­ nected to a joint displacing member in the way shown schematically in Fig. 3A, said displacing member being advantageously the displacing mechanism 29 for a doctor, already existing at a paper mill. When the inner face of the cylinder mantle is being ground, the roll is rotated on its original bearings by means of a rotating device (not shown in the figure). The mantle 11 (arrow L₁) is rotated slowly, and at the same time the grinding ribs are displaced in an oscil­ lating way (arrow L₂) and grinding paste or grinding fluid is possibly supplied through the ducts 17′,18′ and 19′ to the contact and grinding face between the grinding ribs 20,21 and the inner face 11′ of the mantle 11. The grinding ribs are favourably made of poly­ styrene plastic into which aluminium oxide particles have been mixed to constitute grinding material. Generally speaking, it is possible to use amide plastics into which ceramic oxides have been mixed, for example silicon carbide oxide or silicon nitrite oxide. The suction roll is shifted from the paper machine into the roll warehouse of the paper mill, and the seals are substituted for by grinding ribs in accord­ ance with the invention. The grinding is preferably carried out at the storage site for spare rolls at the paper mill, said site being provided with a rotating de­ vice for rotating the roll mantle. The devices that produce the longitudinal movement of the seals may con­ sist of a doctor displacing mechanism present at the paper mill as a spare part. An advantageous length of displacing of the grinding ribs is 50 mm, and together with the rotating of the roll mantle and the supply of grinding fluid the mantle face can be ground smooth and clear of the grooves formed into it by the seals. Such an embodiment of the invention is also possible in which, in stead of grinding ribs, exclusively grinding paste or grinding fluid supplied through the lubricant supply chamber 17′,18′,19′ is used, said grinding material being carried further onto the face between the axial seals and the mantle.

Claims: 1. Method for renewal of the inner face of the roll mantle of a suction roll, characterized in that the suction box (12) of the suction roll is pro­ vided with at least one grinding rib (20 and/or 21) and/or with means (17′,18′,19′) for the supply of grinding mate­ rial, by means of which the inner face (11′) of the roll mantle (11) is renewed by grinding while rotating the roll mantle (11). 2. Method as claimed in claim 1, char­ acterized in that the axial seals of the suction box (12) are removed and grinding ribs (20,21) are placed in their place. 3. Method as claimed in claim 1 or 2, characterized in that the pressure medium ducts passing to the axial seals (15,16) of the suction box (12) are connected to a source of grinding material for the supply of grinding material to the face (11′) to be ground. 4. Method as claimed in any of the preceding claims, characterized in that during the grinding the grinding ribs (20,21) are displaced in the direction of their longitudinal axis (arrow L₂) while the roll mantle (11) is, at the same time, rotated (arrow L₁) by means of the rotating device on its original bearings. 5. Equipment used in the method as claimed in any of the claims 1 to 4, characterized in that the equipment comprises at least one grinding rib (20 and/or 21) grinding the inner face (11′) of the mantle (11) of the suction roll and to be fitted in the suction box (12) of the suction roll of the paper machine. 6. Equipment as claimed in claim 5, characterized in that the grinding rib (20, 21) contains amide plastic into which ceramic oxides have been mixed as grinding material. 7. Equipment as claimed in any of the preceding claims 5 or 6, characterized in that the grinding rib (20,21) is made of polystyrene plastic into which aluminium oxide particles have been mixed as grinding material. 8. Equipment as claimed in any of the preceding claims 5 to 7, characterized in that the equipment includes a grinding-material supply duct passing to the suction box (12) in the suction roll of the paper machine. 9. Equipment as claimed in claim 8, char­ acterized in that the grinding-material supply duct (17′,18′,19′) is fitted to end in the pressure-medium supply duct (17,18,19) at the axial seals (15,16) of the suction box (12). 10. Equipment as claimed in any of the pre­ ceding claims 5 to 9, characterizedin that there is an equipment (29) that produces a reciprocating longitudinal movement (L₂) of the grinding ribs (20,21) placed in the suction box (12) of the suction roll. 11. Equipment as claimed in the preceding claim, characterized in that the equipment that produces the longitudinal movement (L₂) of the grinding ribs (20,21) comprises a lever arrangement (22, 23,24,25,26,27,28) or equivalent, which is passed through the end plate of the suction roll out of the suction roll (11) and connected to a displacing mechanism (29). 12. Equipment as claimed in any of the pre­ ceding claims 5 to 11, characterized in that the equipment for renewal of the inner face (11′) of the roll mantle (11) of a suction roll includes a roll-mantle (11) rotating device.

Inventors: SAVOLAINEN, EERO
Applicants: VALMET PAPER MACHINERY INC.
Application year: 1988
Main classification: D21F3
IPC codes: D21F3