Calender

Name:
Calender
Detailed information:
A machine in which material is passed between heated steel rolls for any of several purposes: (1) to convert it into a sheet of uniform thickness; (2) to cause it to impregnate a textile fabric; or (3) to increase its surface gloss and hardness. Calenders (i.e., cylinders) are composed of from three to as many as 10 or 12 hollow cast-iron rolls up to 84 in. in width, set vertically in a frame. The standard rubber or plastics calender has three steam-heated rolls that turn in opposing directions, either at the same speed or different speeds. When moving at the same speed they deliver the mixture fed between the top and center rolls in a smooth sheet that can be as thin as 0.005 inches, from between the center and bottom rolls. If fabric impregnation is desired, the center roll runs faster than the other two, thus pressing the soft and tacky mixture, called friction, into the textile material (tire carcasses, electrical tape, etc.). In paper manufacturing a high-speed calender “stack” imparts a smooth finish to the sheet as it leaves the drying unit. Smaller calenders are used to apply coating compositions. Laboratory sizes of all types are available.See Supercalender.