Climbing and falling film evaporators cannot be adapted to evaporation
processes when the scaling tendency is high (the tubes have to be full of
liquid, with no boiling in them). This is the only reason why Kestner developed
forced circulation evaporators.
In these evaporators, the tube bundles simply serve to heat the processed
liquor, which then flashes in the separator. In this case, the tubular heater
can either be vertical or horizontal.
To circulate the liquor through the unit, Kestner use special pumps (axial
or mixed flow pumps), which ensure a large flow rate against a moderate head of
liquid.
A: Product
B: Vapor
C: Concentrate
D:
Heating Steam
E: Condensate
1: Calandria
2: Separator (Flash
Cooler)
3: Circulation Pump
4: Concentrate pump