Typically milk fats are maintained between 40 and 60 degrees Celsius. The critical difference between this and caustic - from a heating stand point - is that this will be frequently CIP cleaned. Because of this cleaning we must use a different heat trace cable.
Remember that self-regulating (heat cable, heat tape) heat trace is set out in families and they can maintain and with stand different temperatures. So we need to choose a heat trace that can maintain the temperature required but also the extremities that the heat tracing could be exposed to.
In this case the CIP cleaning high temperature could be in excess of 80-85deg. C. This puts it outside the limits of the BSX type cable, and into the HTSX or KSX heat trace cable.
When using HTSX or KSX the following factors need to be considered:
What is the maximum temperatures that this (heat tape) heat trace could get the product to?
It has a maximum maintain temp of 121 deg.c this is typically much hotter than needed so the use of a controller is necessary.
We still design to maintain the AMF line at the temperature required, plus a safety factor for the worst conditions (rain wind snow freezing).
But in the best, optimal conditions the temperature will swing a long way above the temperature required. In this case the temperature controller is not for heat tracing protection, but for product protection.
For more info on heating milk fats using heat trace cable, call Vaughan on 021 401 444.