Analysis of the Effect of Four Types of Rubber-Covered Pressure Rollers Providing Uniform Load Distribution to a Mangle

Abstract

There are many types of rubber-covered pressure rollers which provide nip uniformity by making the load distribution of a mangle uniform. In this paper, four types of rubber-covered pressure rollers are dealt with analytically. The first one is the pressure rollers supported at their central zone. The second one is a combination of a pressure roller mentioned above and a conventional roller supported at both ends. The third one is the so-called aqua-roller. The last one is rubbercovered rollers with a cambered covering, or with a cambered mandrel.
Flexural behavior of these four types of rubber-covered pressure rollers is analysed using the mathematical theory derived in an earier paper. The following are conclusions obtained from the analytical investigations :
(1) The shape of the mandrel of rubber-covered pressure rollers providing a mangle with a uniform load distribution are found to be independent of the size and the elasticity of the rubber covering.
(2) Some factors of the mandrel shape must be determined with a sufficient accuracy.Otherwise, uniformity of load distribution is degraded considerably.
(3) The uniformity indexes of load distribution of four types of pressure rollers discussed in this paper and two types of covered rollers previously analysed by the authors are compared.They are listed below in a descending order of the uniformity index :
1) Rubber-covered rollers with a cambered covering or with a cambered mandrel,
2) an aqua-roller and a conventional covered pressure roller pressed together,
3) pressure rollers supported intermediately,
4) pressure rollers supported at the central zone,
5) moment compensation pressure rollers, and
6) a combination of pressure rollers of different supporting positions.
(4) There exist an amount and a shape of the surface camber of coverings and mandrels which provide a mangle with a rigorously uniform load distribution for any combination of rubbercovered pressure rollers.