The looper of continuous steel strip mill usually has the following forms: horizontal looper, vertical looper, looper pit and spiral looper. The following is a brief introduction to the characteristics of these loopers:
(1) Horizontal looper is generally set above the equipment or below the floor, with small floor area, large storage capacity and simple structure, which is suitable for the unit with limited length direction in the workshop.
(2) Vertical looper: also known as looper tower, most suitable for thin steel strip storage device. Its advantage is that it can get a large amount of sleeve filling in the case of small space occupation, and it is easy to control the operation and tension of the steel strip. When the strip is broken, the upper turning roll can be braked to keep the strip in good condition. The vertical looper can be divided into two forms: upper group moving, lower group fixing, long group fixing and lower group moving. The lower shoe group is fixed and the upper roller group moves. The advantage of the fixed lifting group is that it is convenient to wear and maintain the belt on the ground or in the pit.
(3) Looper pit: it is a steel strip storage method used earlier in continuous unit. There are many disadvantages in this way. The bending of each looper is easy to cause friction with the surface of the steel strip, which affects the surface quality of the steel strip. In addition, the mechanical load of the first pair of pinch rolls behind the looper pit is too large. On the one hand, it has to pull out the steel strip from the looper pit, and on the other hand, it has to adjust the sag in the cleaning tank of the process section through it, so the color coating unit hardly adopts this form.
(4) Spiral looper: this kind of looper is only suitable for narrow width and low speed continuous line. The friction between steel strips has a great influence on the quality of products, so it is rarely used in color coating line.
No matter what kind of looper, the operation of the steel strip in the looper should be stable, without torsion and tensile deformation