Working principle of coiler
2024/08/07 14:03
The coiler with tension reel is applied to reversible or irreversible cold rolled steel plate or strip steel rolling line. This coiling machine is not only used for coiling (unrolling) rolled pieces, but also to produce tension in the rolled pieces. This is to keep the rolling process stable, to make the plate coil tighter, and to make the rolled pieces in the correct direction when feeding into and out of the roll. During the rolling process, it is generally necessary to maintain a front tension and a back tension. Relying on these tensions, the pressure acting on the roll during rolling can be reduced, and the warping of the strip can be reduced, which is beneficial to improve the surface quality of the strip.
On a single stand reversible cold mill, coilers with tension drums are installed before and after the mill, which alternately become active or driven; that is, one coiling and the other unwinding. On the continuous or irreversible single stand cold rolling mill, only the coiler is installed at the rear of the rolling mill, and the uncoiler is installed in front of the rolling mill.
When the first pass is rolled, the strip is fed from the uncoiler to the back of the mill work roll. Press the strip steel with a pressure plate or a roller guide plate to produce a small post-tension for rolling; then, the strip steel enters the jaw of the coiler drum, clamps the strip steel head for coiling, and produces a pre-tension. The disadvantage of reversible cold rolling is that the strip cannot be rolled at both ends. In order to reduce the consumption of scrap at both ends, large diameter steel coils are often used or welded at both ends of the strip.
In the process of coiling strip steel, the diameter of the steel coil is changing, which causes the continuous change of the coiling speed. In order to adapt the coiling speed to the rolling speed and keep the tension constant when the strip is rolled, the speed of the coiler is required to be adjustable, and the speed range should be adapted to the change of rolling speed and the diameter of the steel coil. Therefore, the adjustable speed DC motor is generally used.
At the end of the rolling, the steel coil is to be unloaded from the reel, therefore, the coiler reel must be made of cantilever type. However, the drum is under a lot of tension to take the strip steel, so that the drum shaft will bear a lot of load (including the weight of the drum, the weight of the strip steel coil, bending strip steel and tension caused by the moment, etc.). In order to ensure the rigidity and strength of the reel shaft and reduce the bending of the reel shaft, in addition to increasing the size of the reel shaft, a rotatable bracket is generally installed at the free end of the reel. When coiling strip steel, the support supports the free end of the reel. However, when unloading the coil, the bracket turns to the side without hindering the unloading of the coil. When unloading the coil, use the pusher or the pusher with the roll unloading trolley to push the steel coil out of the reel and then transport it away. Figure 9-2 is a schematic diagram of the coiler. It consists of a hydraulic cylinder 1 and a push plate 3. The coiler is generally located below the reel, and its stroke is controlled by a limit switch. The pushing plate itself is a trolley, which can run back and forth along the track parallel to the drum to realize the pushing work.
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