The forced circulation evaporator uses a pump to circulate liquid through steam-jacketed tubes at high pressure, preventing boiling. This superheated liquid exits the tubes into a flash chamber where the sudden pressure drop causes flashing to vapor. A deflector separates the vapor from the concentrated liquid, which returns to the pump for further evaporation. Forced circulation provides efficient heat transfer, separation of phases, and suitability for concentrating thermolabile or high viscosity substances, though the equipment has higher costs due to powering the pump.

1. FORCED
CIRCULATION
EVAPORATOR

2. PRINCIPLE
• Liquid circulated through the steam jacketed
tubes at high pressure by means of a pump
• Hence boiling does not take place because boiling
point is elevated
• Forced circulation of liquid also creates some
form of agitation
• This hot liquid leaves the tubes and enters the
vapor head, pressure falls suddenly
• Thus flashing of super heated liquor occurs
• Then vapor and liquid separated effectively

4. CONSTRUCTION
• The steam jacketed tubes are held between two
tube sheets
• Inside diameter – 0.1 m
• Length – 2.5m
• The part of tubes projected in to the vapor head
(flash chamber)
• Deflector
• Vapor head connected to a return pipe which
runs downward and enters in to the inlet of a
pump

5. WORKING
• Steam introduced in to the calendria
• Pump sent the liquid to the tubes with a high
positive velocity
• As the liquid moves up through the tubes ,the
liquid absorb heat from the calandria and get
heated and it starts to produce vapor
• Vapor and liquid mixture rushes out of the
tubes at a high velocity

6. • This mixture strikes the deflector which
throws the liquid downward
• This result in an effective separation of liquid
and vapor
• The vapor enters the cyclone separator and
leaves the equipment
• The concentrated liquid returns to the pump
for further evaporation
• Finally the concentrated product is collected

7. USES
• If evaporation conducted under reduced
pressure forced circulation evaporator is
suitable for thermolabile substances
• Used for concentration of insulin and liver
extracts

8. ADVANTAGES
• Heat transfer coefficient is high due to rapid
liquid movement
• Salting, scaling and fouling are not possible
due to forced circulation

9. ADVANTAGES
• This evaporator is suitable for thermolabile
substances because of rapid evaporation
• Suitable for high viscous preparations because
pumping mechanism

10. DISADVANTAGES
• Equipment is expensive because power is
required for circulating the liquid

11. THANK YOU