When does a plate and frame heat exchanger need to be cleaned?
These units are designed to handle clean, clear liquid and are considered as self-cleaning in view of the relative high turbulence between the plates and the constant “scrubbing” by the flowing liquid. The plates will eventually get coated with a film of minerals deposited by the flowing liquid. The rate of deposit/film formation is dependent on the nature of the fluid pumped through the units, flow rates, temperatures and pressures. The obvious sign is increased pressure drop. Thus, if the differential pressure across the unit is still within acceptable limits, there should be no need to open-up the unit. Back-flushing of the Plate & Frame as well as CIP (clean-in-place) are good options to investigate before the decision to tear the unit apart is finalized.
