|
A Thin
Film Evaporator consists of a jacketed cylindrical heating
section, a top vapor section with an entrainment
separator, a top cover with mechanical seal housing and roller
bearings, and a bottom conical section housing the lower bearing.
An internally
revolving rotor equipped with either wipers or blades provides
internal distribution and rapid transport of the product film
over the heated area. Evaporation often takes place under
vacuum at pressures greater than 1 mmHg abs. The disengaged
vapors are either condensed externally in a tubular/spiral
condenser, or led to a column, or to another downstream process.
The type
of wiper or rotor design is a function of product behavior
and process requirements, for example fouling/deposit formation
tendencies, viscosity, residual moisture requirements, etc.
Three
basic types are available: Rigid blade rotor (fixed clearance
between blade tip and heating surface), rotor with radially
moving wipers (wiped film with either PTFE or graphite elements),
and rotor with hinged free-swinging wiper blades (wiped film
metal wipers or metal wipers with PTFE tips)
|
