Batch Type Pan Evaporator Video Lecture | Heat Transfer - Mechanical Engineering

in batch type pan evaporator the product
is either heated in a steam jacketed
vessel as shown in this photograph where
we have steam that is fed into an
outside jacket around the vessel or the
product is heated in a vessel that
contains steam coils a steam will then
condense inside the coils and the heat
will be transferred into the liquid food
typically the vessel is open to the
atmosphere or it may be connected to
vacuum as we see here in this animation
vacuum is used to boil the liquid at a
temperature below its boiling point this
allows concentrating products that are
heat sensitive also as we see in this
animation as the steam condenses in the
outside jacket it leaves as a condensate
and once the product has concentrated to
the required concentration values it is
then discharged we notice that the heat
transfer area is quite small the heating
of product is by natural convection that
means that the residence time that is
the time that the liquid food spends
inside the vessel is rather long and
therefore the processing capacity in
these types of evaporators is also low
sometimes paddles may be used inside the
vessel for agitation to improve the rate
of heat transfer also when coils are
used sometimes they may be rotated
inside the vessel again to increase the
of heat transfer