3. CLIMBING FILM EVAPORATOR
• RISING FILM EVAPORATOR
PRINCIPLE
• The preheated feed enters from the bottom
and flows up through the heated tubes
• The liquid gets heated rapidly due to overall
heat transfer coefficient
• The liquid near the wall become vapor and
forms small bubbles
4. • These bubbles fuse to form larger bubbles and
it entrap liquid slug and travel up in the tubes
• As more vapor formed this bubbles are blown
up from the top of tubes and strike the
deflector
• This throws the liquid concentrate downward
• Vapor escape through the vapor outlet
5. CONSTRUCTION
• The heating unit consists of steam jacketed tubes
• This long narrow tubes are held between two
plates
• An entrainment separator is placed at the top to
the vapor head
• Steam inlet
• Vent
• Condensate outlet
• Feed inlet- at the bottom of the steam
compartment
6. WORKING
• The preheated liquid feed introduced from the
bottom of the unit
• Steam introduced through the steam inlet in
to the space outside the tubes
• Heat is transferred to the liquor through the
walls of the tubes
• The liquid becomes vapor and forms smaller
bubbles
7. • This bubbles tend to fuse to larger bubbles
• The bubbles formed having the same
diameter as that of tubes
• So this bubbles trap a part of liquid on its way
up in the tubes
• As more vapor is formed the slug of liquid
blown up from the top of the tubes and it
spread as a liquid film over the walls
8. • This liquid film continues to vaporize rapidly
• Finally the mixture of liquid concentrate and
vapor eject at a high velocity from the top of
the tubes
• The entrainment separator act as a foam
breaker , it separate the entrained liquid slugs
from the vapor
• The vapor leaves from the top while
concentrate is collected from the bottom
9. USES
• Thermolabile substances –insulin, liver
extracts, vitamins
• Clear liquids, foaming liquids and corrosive
solutions in large quantities can operated
10. ADVANTAGES
• Long and narrow tubes provide large heating
area
• The time of contact between the liquor and
the heating surface is very short. Suitable for
thermolabile materials
• Suitable for foam forming liquids, because
foam can be broken by an entrainment
separator
• Small flour space
