The steam circulate
s through a series of small longitudinal holes near the surface of the rolls. The holes are matched in pairs so that the first pass carries steam from the inlet and the second pass returns the steam to the outlet. Since the steam moves faster, the condensate does not get trapped within the rolls. The major advantages of the peripheral heating system are as follows:
- Higher roll surface temperature given steam pressure.
- Homogeneous temperature distribution across the rolls
- No condensate accumulation in the rolls, and no banana shape at the start up.