Device for reconditioning of a sealing face on a drying cylinder of a paper machine

Abstract: The invention concerns a method for reconditioning of the sealing face (11) at the opening of the manhole (10) of a drying cylinder (K) of a paper machine when the cylinder (K) is in its operating position in the paper machine. In the method a separate frame part (13) is attached to the cylinder end. The frame part (13) comprises guides (15a,15b), along which a machining unit (16) is displaced which is fitted to machine the sealing faces. The invention also concerns a device for use in the method.

Description: Device for reconditioning of the sealing face on a drying cylinder of a paper machine The invention concerns a device for reconditioning of the sealing face on a drying cylinder of a paper machine. In ageing paper machines, a problem has been the sealing faces of the manholes at the drying cylinders being corroded such that it has not been possible to guarantee good sealing by means of the currently available seal materials. The reconditioning of the sealing face placed at the end of a cylinder has proved particularly laborious. The reconditioning of the manhole of the door itself is no problem, because it can be carried easily to the machine tool. In stead, the conditioning of the sealing face on the roll end, to be fitted against the door, has caused problems. Disassembly of the construction has required a considerable amount of time and, thus, the cost of reconditioning has become high as a paper machine comprises a number of seal faces to be reconditioned. The document US-A-4 513 542 discloses a portable grinding device for reconditioning a sealing surface of a rim of an opening such as a manhole in an object, i.e. a boiler. The device comprises a machining unit and a frame part which is attached to the opening of the object to be machined and which has guides for guiding the machining unit. This machining unit is movable along said guide for grinding the sealing surface. Furthermore, this device has a motor which is, additionally to the machining unit, disposed inside the object to be machined. Thus, the device as a whole has a high weight and applies high load to the frame. Furthermore, the rotational movement of the machining unit in order to machine the whole sealing surface is transmitted by the spindle causing an additional moment thereto. It is the object of the invention to provide a device for reconditioning of sealing surfaces of a manhole without the necessity of dismantling the object to be machined, while the device has low weight and good handling and operating characteristics. This object is achieved by an apparatus comprising the features according to claim 1. A low-weight structure which can be easy handled is achieved in that the motor is situated outside the object to be machined and in that there is provided a hollow shaft attached to the motor through which a driving shaft extends inside the object to be machined for driving the grinding tool. Further advantageously improvements of the present invention are claimed in the subclaims 2 and 3. According to the invention, it has been realized to provide a low-weight portable device, which is supported by its frame on the constructions of the end flange of the roll and in which method the device comprises guides which comply with the shape of the manhole opening and along which the reconditioning device is passed. The invention will be described in the following with reference to some preferred embodiments of the invention illustrated in the figures in the accompanying drawings, the invention being, however, not supposed to be confined to said embodiments alone. Figure 1 shows the object of reconditioning, a drying cylinder of a paper machine. Figure 2 shows a device in accordance with the invention as installed at the end of the cylinder. Figure 3 is a sectional view taken along the line I-I in Fig. 2. Figure 4 is a more detailed illustration in part of the embodiment of Fig. 2. Figure 5 shows a second preferred embodiment of the device of the invention. Fig. 1 shows a drying cylinder K of a paper machine. The manhole passing into the interior of the drying cylinder K of a paper machine is denoted with the reference numeral 10. The sealing faces 11 are fitted so that they can be reconditioned by means of the device in accordance with the invention, which device will be described in more detail in the following and which device is attached to the inner faces T₁ of the opening of the manhole 10. Fig. 2 is a sectional view of a device in accordance with the invention. The reconditioning device 12 includes a frame 13, which is attached to the cylinder end by means of locking pins 14, preferably screws. The frame 13 includes guides 15a and 15b of oval shape. The equipment includes a displaceable machining unit 16 to be passed along the guides. The machining unit 16 comprises guide sledges 17a and 17b, to which rollers 18a,18b,18c,18d are attached correspondingly to both sledge portions 17a and 17b (Fig. 3). The rollers 18a and 18b; 18c and 18d, placed one above the other, are fitted to be supported on the guide parts 15a so that they are in engagement with opposite sides of the guide part. In a corresponding way, the rollers 18 are placed in engagement with the second guide part 15b similarly. The sledges 17a and 17b themselves are connected to the motor 23 shaft 19 so that the sledges can slide on the shaft in the direction of the central axis x of the shaft 19. At its end placed at the side of the motor 23, the shaft 19 has a threading 20 on its outer face, to which threading the nut 21 is attached, whose end face is supported on the sledge 17a. The threading 22 on the nut 21 is compatible with the threading 20 on the shaft 19. A motor 23, preferably a pneumatic motor, is placed at the end of the shaft 19. The output shaft 24 of the motor 23 passes through the shaft 19, and its end is coupled with the drive shaft 27 of the machining tool 26 by means of a belt transmission 25. Also, the shaft 27 is supported on the shaft 19 by means of an auxiliary frame 28. A disk 29 is fixed permanently to the shaft 19, and a compression spring 30 is fitted between the disk 29 and the outer face of the sledge 17b. Thus, the position of the shaft 19 and of the shaft 24 placed in its interior is adjustable by rotating the nut 21 in the threading 20 on the shaft 19 against the spring 30 force. Rotation of the shaft 19 in relation to the sledge 17a,17b is prevented by means of a key between the shaft 19 and the sledge 17b (Fig. 4). On the contrary, the key permits movement of the shaft 19 in the direction of the normal of the face to be machined. Thus, the machining tool can be displaced in the direction of the normal of the face when the machining proceeds. Fig. 2 shows the grinding disk at the stage before machining of the face 11. By rotating the nut 21, the grinding disk 26 can be brought into contact with the face 11 to be machined. The motor itself with the related means is displaced manually along the guides 15a and 15b of oval shape. Fig. 3 is a sectional view taken along the line I-I in Fig. 2. In the figure, the guide 15a of oval shape is seen, along which the equipment is displaced manually. From the figure it is seen further that the shaft 24 which rotates the tool runs inside the shaft 19. Fig. 4 is a more detailed illustration in part of an embodiment of the invention similar to that shown in Fig. 2. The motor 23 is not shown in the illustration in part. From the shaft 24 the movement of rotation is transferred to the belt pulley 31 and from the belt pulley 31, by the intermediate of the belt 32, to the driven belt pulley 33, which is fitted further to rotate the shaft 27 of the grinding disk 26. As is shown in the figure, the shaft 27 of the grinding disk 26 is mounted on an auxiliary frame 28 by bearing means 34. The shaft 19 is fixed to the sledges 17a and 17b so that rotation between the parts is prevented by means of the key 35. Fig. 5 shows a second embodiment of the device in accordance with the invention, in which the motor 23 is fitted to rotate the drive shaft 24 fitted inside the shaft 19, the grinding disk 26, preferably a cup wheel, being connected directly to said shaft 24. The cup wheel 26 is in a position from which it is fed into contact with the face 11 to be machined by rotating the nut 21.

Claims: Device for reconditioning a sealing face to be machined, in particular the sealing face (11) at the opening of a manhole (10) of a drying cylinder (K) of a paper machine, said device comprising a frame part (13) to be attached to the end of the cylinder, which frame part (13) includes guides (15a, 15b) and locking pins (14) or equivalent, by means of which said frame (13) can be coupled to the end of the cylinder of the paper machine and positioned in relation to said cylinder end, and a machining unit (16) moved along said guides (15a, 15b), said unit (16) including a motor (23) for rotating a tool (26), and a nut (21) which is provided in a threading (20) of the outer face of said hollow shaft (19) and, by rotating said nut (21), said shaft (19) and said tool (26) connected thereto are fed in a direction away from or towards the surface to be machined. characterized in that said machining unit (16) comprises guide sledges (17a, 17b) provided with sledge rollers (18) or equivalent which move with said guides (15a, 15b), that said guide sledges (17a, 17b) are attached to said hollow shaft (19) connected to said motor (23), that said motor (23) is situated outside the object to be machined during the machining operation, while an output shaft (24) of said motor (23) has been mounted in said hollow shaft (19) by bearing means, and that a spring means is provided between said hollow shaft (19) and said guide sledge (17a, 17b). Device according to claim 1, characterized in that one end of said output shaft (24) is provided with a belt pulley (31), which operates a belt (32), and a related drive wheel (33), to which a shaft (27) of said tool (26) is connected, said shaft (27) being rotatably supported in bearings (34) fitted in an auxiliary frame (28). Device according to any of claims 1 or 2, characterized in that said spring (30) is fitted between said second sledge (17b) and a disk (29) fitted on said shaft (19), said spring (30) providing the counter-force for the feed movement when said nut (21) is rotated in said threading (20) on said shaft (19).

Inventors: HARINEN PEKKA, RAJALA KARI, HARINEN, PEKKA, RAJALA, KARI
Applicants: VALMET PAPER MACHINERY INC, VALMET PAPER MACHINERY INC.
Application year: 1990
Main classification: D21F5
IPC codes: D21F5