Furnace coiler

Abstract: To provide a furnace coiler facilitating maintenance work and improving the yield and the productivity of the associated rolling system. A furnace coiler(200) has a housing having an upper housing (210), a lower housing (220) and a bottom housing (230). The bottom housing (230) can be moved together with movable table rollers (170).

Description: BACKGROUND OF THE INVENTION The present invention relates to a furnace coiler for winding a strip to be rolled by a hot rolling mill, and keeping the strip hot or heating the strip. In a conventional hot rolling system, a furnace coiler takes up a strip rolled by a hot rolling mill and heats the strip. As mentioned in, for example, U.S. Pat. Nos. 5,269,166 and 5,009,092, and Japanese Patent Laid-open Nos. Hei. 7-47422 and Hei. 8-332503, a furnace coiler has a housing and a mandrel disposed in the housing, takes up a strip traveled through table rollers on the mandrel in a coil and heats the coil. Internal devices of the furnace coiler including the mandrel and strip guides, and furnace walls of the furnace coiler are exposed to severe thermal conditions. Therefore, those internal devices and the furnace walls have short lifetimes and require frequent maintenance work. For example, the interior of the furnace coiler needs inspection nearly once every week for maintenance. However, the maintenance of the conventional furnace coiler is difficult. The conventional furnace coiler has a lower housing, and an upper housing fixed to the lower housing with bolts or the like, and the lower housing is provided with an inlet opening to receive a strip therethrough into the furnace coiler. For example, suppose that the furnace coiler is 4 m in diameter and 2 m in width. Then, the inlet opening is as small as 2 m in width and only about 1 m in height. Therefore, it is impossible for a man to enter the housing for maintenance work. Therefore, when removing the internal devices including the mandrel and the strip guides from the housing, the upper housing of the furnace coiler must be removed. Since the upper housing is a heavyweight structure of about 30 tons, it takes two days for four men to remove the upper housing from and recombining the same with the lower housing. Since the housing is closed excluding the inlet opening, it takes a very long time of about 10 hours for the furnace coiler to cool down after the furnace coiler has been stopped. Accordingly, the conventional furnace coiler has problems that the furnace coiler requires difficult maintenance work and reduces the yield and the productivity of the associated rolling system. Accordingly, it is an object of the present invention to provide a furnace coiler not requiring difficult maintenance work and capable of improving the yield and the productivity of the associated rolling system. SUMMARY OF THE INVENTION With the foregoing object in view, the present invention provides a furnace coiler in accordance with claim 1. In this furnace coiler, the bottom housing can easily be moved sideways, an opening formed by moving the bottom housing can be used for cooling the interior of the housing to facilitate maintenance work and to improve the yield and the productivity of the associated rolling system. Table rollers are disposed below the furnace coiler to pass a strip to be worked through a rolling mill, and some of the table rollers are movable together with the bottom housing. The bottom housing can easily be moved together with the movable table rollers. In accordance with claim 2, it is preferable that a joint between the lower housing and the bottom housing has a heat insulating construction. The heat insulating joint prevents heat leakage and improves safety. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a front view of a hot rolling system including a furnace coiler in an embodiment according to the present invention. Fig. 2 is a sectional view taken on line A-A in Fig. 1, illustrating a bottom housing moving mechanism included in the furnace coiler in the embodiment according to the present invention. Fig. 3 is a front view of a hot rolling system including a furnace coiler in an example useful to understand the present invention. DETAILED DESSRIPTION OF THE PREFERRED EMBODIMENT A furnace coiler in an embodiment according to the present invention will be described with reference to Figs. 1 and 2. First, a hot rolling system including the furnace coiler in the embodiment will be described with reference to Fig. 1. Fig. 1 is a front view of a hot rolling system including the furnace coiler in the embodiment according to the present invention. A reversing rolling mill 100 presses a hot strip or a hot slab between an upper roll 110 and a lower roll 120 for rolling. Furnace coilers 200 for keeping the strip hot or heating the strip are installed on the front and the back side of the reversing rolling mill 100. Only one of the furnace coilers 200 is shown in Fig. 1. The two furnace coilers 200 are disposed in a symmetrical positional relation with respect to the reversing rolling mill 100. Table rollers 130 are disposed adjacent to the reversing rolling mill 100. The strip or the slab to be worked is carried by the table rollers 130 for forward and backward movement so that the strip or the slab is worked repeatedly for rolling by the reversing rolling mill 100. The strip to be worked is moved forward or backward by pinch rollers 140 driven by a motor. During a normal rolling operation, a lower guide 160 is set at its lower position where the lower guide 160 is included in a plane in contact with the upper parts of the table rollers 130 to avoid obstructing the movement of the strip. When taking up the rolled strip by the furnace coiler 200, the lower guide 160 is turned upward on a pivot pin 165 connected to one end thereof to guide the rolled strip delivered from the reversing rolling mill 100 toward. the inlet opening of the furnace coiler 200. The furnace coiler 200 in the embodiment has a housing having an upper housing 210, a lower housing 220 and a bottom housing 230. The embodiment is characterized by the housing provided with the bottom housing 230 in addition to the upper housing 210 and the lower housing 220. The upper housing 210 and the lower housing 220 are fastened together with bolts or the like. On the other hand, the bottom housing 230 is not fastened to the lower housing 220.and can be moved toward an operating side (in a direction out of the paper in Fig. 1). The bottom housing 230 is fixed to brackets 232 attached to a table roller base 172 supporting movable table rollers 170 for rotation. The movable table rollers 170 are separated from the adjacent stationary table rollers 130. Wheels 174 disposed under the movable table rollers 170 roll on rails 180 fixedly laid on a base. The bottom housing 230 fixedly held over the movable table rollers 170 can be pulled out toward the operating side by moving the movable table rollers 170 in a direction out of the paper in Fig. 1. A groove 222 is formed in an end part of the lower housing 220, a ridge 234 is formed in an end part of the bottom housing 230, and the ridge 234 of the bottom housing 230 is fitted in the groove 222 of the lower housing 220 in a tongue-and-groove joint to prevent flames produced in the heating furnace from leaking outside. The tongue-and-groove joint prevents the reduction of the ability of the heating furnace due to the leakage of heat generated in the heating furnace for keeping a strip hot or heating a strip through gaps between the lower housing 220 and the bottom housing 230, and improves safety by preventing high-temperature hot air from blowing out through the gaps. A clearance is formed between the bottom housing 230 and the lower housing 220 to prevent thermal deformation. The furnace coiler 200 is internally provided with a mandrel 240. The mandrel 240 is driven for rotation by a motor to take up the strip. The motor which drives to rotate the mandrel 240 is disposed on the other side of the furnace coiler 200 opposite the operating side and, therefore, the movable table rollers 170 can be pulled out toward the operating side. The furnace coiler 200 has an opening X, and an upper guide 250 is disposed in the opening X to guide the leading edge of the strip to the mandrel 240 at the start of a strip winding operation. The upper guide 250 turns on a pivot pin 252 placed at one end of the upper guide 250. At the start of the strip winding operation, the upper guide 250 is turned upwardly to guide the leading edge of the strip guided thereto by the lower guide 160 to a gripping slit 242 formed in the mandrel 240. Upon the start of a normal winding operation after the leading edge of the strip has been gripped by the mandrel 240, the upper guide 250 is turned downward on the pivot pin 252 so that the upper guide 250 may not interfere with the strip wound on the mandrel 240 during the normal winding operation. The furnace coiler 200 is provided with other devices including a heating device, not shown, for keeping the strip hot or for heating the strip. A bottom housing moving mechanism included in the furnace coiler 200 in the embodiment will be described with reference to Fig. 2. Fig. 2 is a sectional view taken on line A-A in Fig. 1, illustrating the bottom housing moving mechanism included in the furnace coiler in the embodiment according to the present invention. The movable table rollers 170 are supported for rotation in bearings 178 fixedly held on brackets 176 fixedly mounted on the table roller base 172 supporting the movable table rollers 170. The movable table rollers 170 are driven for rotation by motors 190. The bottom housing 230 is fixed to the brackets 232 fixedly mounted on the table roller base 172. The wheels 174 are attached to the lower surface of the table roller base 172, and the table roller base 172 can be moved along the rails 180 shown in Fig. 1 in the direction of the arrow Y (toward the operating side of the furnace coiler 200). The bottom housing 230 can be moved in the direction of the arrow Y together with the movable table rollers 170. The bottom housing 230 and the movable table rollers 170 are moved mechanically by a cylinder actuator, not shown, or the like. Thus, the bottom housing 230 can easily be moved, and an opening formed by moving the bottom housing 230 facilitates maintenance work. When removing the upper housing of the conventional furnace coiler, the bolts fastening the upper housing to the lower housing must be removed and the upper housing must be lifted up and carried away by a crane or the like, this upper housing removing steps must be reversed conventionally when assembling the upper housing and the lower housing. Thus, work for removing the upper housing from the lower housing and assembling the upper housing and the lower housing takes two days conventionally. On the other hand, work for moving the bottom housing can be accomplished in a half day in the resent invention. Whereas work for removing the upper housing needs four men conventionally, work for moving the bottom housing 230 needs two men in the present invention. The bottom housing 230 can be moved even while the interior of the furnace coiler 200 is hot. An opening formed in the housing after the bottom housing 230 has been removed may have a large area up to the sum of the area of an opening corresponding to the bottom housing 230 and the area of the opening X, and is, for example, 2 m in width and 2.5 m in height. Since such a large opening is formed in the housing, the interior of the furnace coiler 200 can cool down in a short time. Whereas it takes, for example, 10 hours for the interior of the furnace coiler 200 to cool down when an opening of 2 m in width and 1 m in height is formed in the housing conventionally, it takes only 5 hours for the interior of the furnace coiler 200 to cool down when an opening of 2 m in width and 2.5 m in height is formed in the housing. As shown in Fig. 2, heat-insulating sealing members 260 are placed in the contact surfaces between the lower housing 220 and the bottom housing 230 to prevent the leakage of heat through gaps between the lower housing 220 and the bottom housing 230. The heat-insulating sealing members 260 may be made of a material formed by covering a ceramic fiber bracket with a ceramic fiber cloth. The heat-insulating sealing members 260 serves also as cushioning members which relieve impact of collision between the lower housing 220 and the bottom housing 230 when the bottom housing 230 and the movable table rollers 170 pulled out toward the operating side for maintenance are returned to the furnace coiler 200 after the completion of maintenance. Maintenance work for the maintenance of the internal components of the furnace coiler 200 will be described below. After the operation of furnace coiler 200 has been stopped, the bottom housing 230 and the movable table rollers 170 are moved along the rails 180 toward the operating side, and the furnace coiler 200 is left to cool down naturally. After the furnace coiler 200 has cooled down, the operators enter a space formed after removing the bottom housing 230 and execute maintenance work for the maintenance of the furnace equipment including the mandrel 240, the upper guide 250, the furnace walls, the heating device and the like. After the maintenance work has been accomplished, the bottom housing 230 and the movable table rollers 170 are returned to the furnace coiler 200 side so that the bottom housing 230 is joined to the lower housing 220. Although the bottom housing 230 and the movable table rollers 170 are moved toward the operating side (in a direction out of the paper in Fig. 1) in this embodiment, the bottom housing 230 and the movable table rollers 170 may be moved down into and kept in a hollow formed under the movable table rollers 170. As is apparent from the foregoing description, in the embodiment, the upper housing need not be removed, the bottom housing and the movable table rollers can easily be moved, and hence the maintenance of the furnace coiler can easily be carried out. Since the large opening can be formed by moving the bottom housing, the interior of the furnace coiler is able to cool down in a short time, and thereby time necessary for maintenance can be reduced. Since the bottom housing and the lower housing are joined by the tongue-and-groove joint, the leakage of heat can be prevented and safety can be improved. A furnace coiler in an example useful to understand the present invention will be described with reference to Fig. 3. Fig. 3 is a front view of a hot rolling system including the furnace coiler in the example, in which parts like or corresponding to those shown in Fig. 1 are designated by the same reference characters. The hot rolling system shown in Fig. 3 is similar to that shown in Fig. 1, except that the furnace coiler 200A included in the hot rolling system shown in Fig. 3 is different from the furnace coiler 200 included in the hot rolling system shown in Fig. 3. Furnace coilers 200A for keeping a strip hot or heating the strip are installed on the front and the back side of a reversing rolling mill 100. Only one of the furnace coilers 200A is shown in Fig. 3. The two furnace coilers 200A are disposed in a symmetrical positional relation with respect to the reversing rolling mill 100. The furnace coiler 200A in the example has a housing having an upper housing 210, a lower housing 220 and a bottom housing 230A. The upper housing 210 and the lower housing 220 are fastened together with bolts or the like. The bottom housing 230A supported on the lower housing 220 by a pivot pin 236 so as to be rotatable on the pivot pin 236. Movable table rollers 170 are separated from adjacent fixed table rollers 130. Wheels 174 disposed under the movable table rollers 170 roll on rails 180 fixedly laid on a base to move the movable table rollers 170. The movable table rollers 170 can be pulled out toward the-operating side. The furnace coiler 200A is internally provided with a mandrel 240. The mandrel 240 is driven for rotation by a motor to take up the strip. The motor is disposed on the other side of the furnace coiler 200A opposite the operating side and, therefore, the movable table rollers 170 can be pulled out toward the operating side. The furnace coiler 200A has an opening X, and an upper guide 250 is disposed in the opening X to guide the leading edge of the strip to the mandrel 240 at the start of a strip winding operation. The upper guide 250 turns on a pivot pin 252 placed at one end of the upper guide 250. At the start of the strip winding operation, the upper guide 250 is turned upwardly to guide the leading edge of the strip guided thereto by a lower guide 160 to a strip gripping slit 242 formed in the mandrel 240. Upon the start of a normal winding operation after the leading edge of the strip has been gripped by the mandrel 240, the upper guide 250 is turned downward on the pivot pin 252 so that the upper guide 250 may not interfere with the strip wound on the mandrel 240 during the normal winding operation. The furnace coiler 200A is provided with other devices including a heating device, not shown, for keeping the strip hot or for heating the strip. The bottom housing 230A is operated and the movable table rollers 170 are moved mechanically by cylinder actuators, not shown. Thus, the bottom housing 230A can easily be turned, and an opening formed after opening the bottom housing 230A facilitates maintenance work. Maintenance work for the maintenance of the internal components of the furnace coiler 200A will be described below. After the operation of the furnace coiler 200A has been stopped, the movable table rollers 170 are moved along the rails 180 toward the operating side, the bottom housing 230A is opened and the furnace coiler 200A is left to cool down naturally. After the furnace coiler 200A has cooled down, the operators enter a space formed after removing the bottom housing 230A and execute maintenance work for the maintenance of the furnace equipment including the mandrel 240, the upper guide 250, the furnace walls, the heating device and the like. After the maintenance work has been accomplished, the bottom housing 230A is closed and the movable table rollers 170 are returned to the furnace coiler 200A side. As is apparent from the foregoing description, the upper housing needs not be removed, the bottom housing can easily be opened, the movable table rollers can easily be moved, and hence maintenance work is facilitated. Since a large opening can be formed by turning the bottom housing for opening, the interior of the furnace coiler can be cooled down in a short time and thereby time necessary for maintenance can be reduced. As is apparent from the foregoing description, according to the present invention, the maintenance of the furnace coiler can easily be carried out and the yield and the productivity of the rolling system can be improved.

Claims: A furnace coiler (200) comprising: a housing having an upper housing part (210), a lower housing part (220) fixed to the upper housing part, and a bottom housing part (230) separate from the lower housing part (220) and placed in a bottom part thereof; table rollers (130, 170) to pass a strip to be worked through a rolling mill (100); and a mandrel (240) disposed in the housing to take up the strip, characterised in that the bottom housing part (230) is fixed to at least some of the table rollers (170) and that both are movable sideways relative to the lower housing part (220). The furnace coiler of claim 1, wherein a joint (222, 234) between the lower housing part and the bottom housing part has a heat insulating construction.

Inventors: OBARA MAKOTO, SUGIMOTO OSAMU, YOSHIOKA TAKAHIRO, OBARA, MAKOTO, SUGIMOTO, OSAMU, YOSHIOKA, TAKAHIRO
Applicants: HITACHI LTD, HITACHI, LTD.
Application year: 1999
Main classification: C21D9
IPC codes: B21B39, C21D9, B21B45, B21C47, B21B1