织物轧光机的辊筒设计
2013-09-11 16:38:43   来源：   评论：0 点击：

It is well-known that calender machines have hard metal bowls and soft fibre, viz, cotton bowls, woollen paper bowls, cotton paper bowls and many more.

Metal bowls are known as heating bowls and fibre bowls as cushion rolls. When metal bowl is engaged with fibre bowl then the nip formation takes place.

The most important factor in a calender is -- DESIGNING THE COTTON BOWL OR ANY OTHER FIBRE BOWL.

A. For a certain nip pressure, the specific pressure on the material to be calendered depends upon the diameter of bowls. Larger the bowl diameter, more will be the contact area on which the nip pressure is acting. Hence specific pressure is less.

B. Dwell-time under specific pressure is also important from the point of view of rate of loading under nip. Low rpm bowls give better loading effects.

Selection of diameter of bowls again depends upon the rpm.

C. Designing of diameter of calender bowl depends upon the width of roll and requirement of nip pressure.

Crown/camber at the centre of bowl depends upon the bowl material and deflection at the required nip pressure.

To be true, same calender bowl may not be useful for varied nip pressures. However, they are suitable for close range adjustments up to + [ - ] 50 kg/cm. No doubt, the hardness too plays an important role in designing and manufacturing of the bowl.

In diagram 1, one observes how larger dia bowls and smaller dia bowls behave. Similarly in diagram 2, the rate of loading is slow in larger bowls and the rate of loading is fast in smaller bowls. So for perfect finish, designing of cotton bowls play an important role in calender stack.