Mill Material Balance

The Roller Deflection X-1

CHAPTER X

THE ROLLER DEFLECTION

The no-void volume of bagasse has a higher value obtained by the calculation when compared

with its escribed volume of the respective work opening. This could happen when the rollers

slightly deflected, especially the top roller during the course of milling (supported by two top

halve metals). But of course it has a maximum value of deflection that could be maintained only

within a certain time by the rollers, which are made of cast iron / cast steel.

Different value of deflections occurred by the roller shell and the shaft made of forged steel, and

based on observation in practice a maximum value of 0.22% limits the deflection for the roller

shells. We have to prevent the deflection not to exceed the limit; otherwise cracks or breakage of

the shell might be occurred.

The calculation is very simple. We have already know the followings:

Vedo = the escribed volume of the delivery work opening, in dm3/hour unit, that is the volume

passed by the set / implemented work opening (h).

Vedo = p . Dk . L . n . h

While:

Ved = the escribed volume of the actual delivery work opening that passed by the actual gap or

work opening made during the course of milling, also in dm3/hour unit.

Ved = p . Dk . L . n . h

It means the different lies on the value of h and h.

So then, when the division of:

Ved Vedo

> 1, it is definitely the mill roller has deflected.

Or, when the deflection percentage calculated by:

(h-h) x 100 L

> 0.22%. The roller works in danger; it can be cracked or broken.

Where: h = the average height of delivery opening when working, in dm unit. h = the actual height of delivery opening when set, in dm. L = the roller shell length, in dm. Notes: The above condition refers for mills provided without hydraulic on its top rollers, or for mills with hydraulics but conditionally limits the top roller lifts.