Type of heat exchanger. Which is mainly used in food industries, like dairy plant, for the pasturization, heat treatment of the beavrages or liquid raw material.

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SAM HIGGINBOTTEM INSTITUTE OF
AGRICULTURE, TECHNOLOGY &
SCIENCES
ASSIGNMENT
APFE 303
ID NO: 15BTFT087
COURSE : B.TECH. FOOD TECH. [2nd
SEM]
SUBMITTED TO: ER. A.A.MISHRA

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INDEX
1) PLATE HEAT EXCHANGER
2) DOUBLE PIPE HEAT EXCHANGER
3) SHELL & TUBE HEAT EXCHANGER

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HEAT EXCHANGER
A device used to transfer heat from one fluid to another
without direct contact of
fluid. Heat exchanger contain a hot fluid that flows through one part
of the exchanger & transfer
it’s heat either to a cool fluid.
example: car radiator etc.
 IN THIS TYPE HEAT EXCHENGER HEAT IS :
[ Q = UAFt(^T lm) ]
HERE
Ft – correction factor ( most of the time 0.85 to 0.9 )
(^Tlm) – LMTD (log mean temp. diff)
 Value of LMTD is

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[ LMTD =
( )
]
1) PLATE TYPE HEAT EXCHANGER
 INTRODUCTION:-
Plate and frame exchangers offer
the highest efficiency mechanism for heat
transfer available in industry today. Some of
the applications where this high efficiency is
evident when using the Graham Brazed or
Gasketed Plate Heat Exchangers are:
Water heaters
Cooling tower isolation
Waste heat recovery
Heat pump isolation

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Thermal (ice) storage systems
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CONSTRUCTION:-
The WCR Plate Heat Exchanger consists of a
specific number of gasketed plates which are
fixed between a top carrying bar and a lower
guide bar.
The plates are compressed by means of tie
bars between a stationary frame plate (the
head) and a moveable frame (the follower).
 Fluids enter the plate heat exchanger through
frame connections and are distributed in
between the plates.
The flow through alternate passages between
the plates is controlled by the placement of
gaskets.
 These are available in single and multi-pass
arrangements, depending upon the
application.
All plate heat exchangers look similar on the
outside. The difference lies on the inside, in
the details of the plate design and the sealing
technologies used.
WORKING:-
Design calculations of a plate heat exchanger
include flow distribution and pressure drop and
heat transfer. The former is an issue of flow

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distribution in manifolds A layout configuration of
plate heat exchanger can be usually simplified into
a manifold system with two manifold headers for
dividing and combining fluids, which can be
categorized into U-type and Z-type arrangement
according to flow direction in the headers, as
shown in manifold arrangement. Bassiouny and
Martin developed previous theory of design. In the
recent years Wang unified all the main existing
models and developed a most completed theory
and design tool.
APPLICATION:-
o In a heat exchanger, heat energy is
transferred from one body or fluid stream
to another.
o In the design of heat exchange
equipment, heat transfer equations are
applied to calculate this transfer of
energy so as to carry it out efficiently and
under controlled conditions.
o The equipment goes under many names,
such as boilers, pasteurizers, jacketed
pans, freezers, air heaters, cookers,
ovens and so on.
o The range is too great to list completely.
Heat exchangers are found widely
scattered throughout the food process
industry.

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2) DOUBLE PIPE HEAT EXCHANGER
INTRODUCTION:-
In double pipe heat exchanger design, an important
factor is the type of flow pattern in the heat
exchanger. A double pipe heat exchanger will
typically be either counter flow or parallel flow.
Cross flow just doesn't work for a double pipe heat
exchanger. The flow pattern and the required heat
exchange duty allows calculation of the log mean
temperature difference. That together with an
estimated overall heat transfer coefficient allows
calculation of the required heat transfer surface

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area. Then pipe sizes, pipe lengths and number of
bends can be determined.
COSTRUCTION:-
The double pipe heat exchanger is constructed by using
metals or alloys that have good heat resistance and
corrosive resistance properties. Normally the size of
double pipe heat exchanger is between 100-200 ft sq.
Following is a list of all pieces of equipment for the
double-pipe heat exchanger.
 Gate valves
 Disk blow valves
 Ball valves
 Computer controlled valves
WORKING AND APPLICATION:-
o Double pipe heat exchanger utilizes true
counter-current flow to which maximizes
the temperature differences between the
shell side and the tube side fluids,
resulting in less surface area required for a
given duty.
o Double Pipe exchangers are especially
suitable for extreme temperature crossing,
high pressure, high temperature, and low
to moderate surface area requirements.

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o So when your process calls for a
temperature cross when the hot fluid
outlet temperature is below the cold fluid
outlet temperature, a hairpin heat
exchanger is the most efficient design and
will result in fewer sections and less
surface area.
o Double-pipe heat exchangers use a single
pipe within a pipe design and are
commonly used for high fouling services
such as slurries, where abrasive materials
are present, and for smaller duties.
Standard shell diameters typically range
from 2” to 6”.
3) SHELL & TUBE HEAT EXCHANGER

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INTRODUCTION:-
A shell and tube heat exchanger is a class of
heat exchanger designs. It is the most common
type of heat exchanger in oil refineries and other
large chemical processes, and is suited for higher-
pressure applications. As its name implies, this
type of heat exchanger consists of a shell (a large
pressure vessel) with a bundle of tubes inside it.
One fluid runs through the tubes, and another fluid
flows over the tubes (through the shell) to transfer
heat between the two fluids. The set of tubes is
called a tube bundle, and may be composed of
several types of tubes: plain, longitudinally finned,
etc.
CONSTRUCTION:-
o There can be many variations on the shell
and tube design.
o Typically, the ends of each tube are
connected to plenums (sometimes called
water boxes) through holes in tubesheets.
The tubes may be straight or bent in the
shape of a U, called U-tubes.
o In nuclear power plants called pressurized
water reactors, large heat exchangers called
stea generators are two-phase, shell-and-tube
heat exchangers which typically have U-
tubes.

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o They are used to boil water recycled from a
surface condenser into steam to drive a
turbine to produce power.
o Most shell-and-tube heat exchangers are
either 1, 2, or 4 pass designs on the tube
side. This refers to the number of times the
fluid in the tubes passes through the fluid in
the shell. In a single pass heat exchanger, the
fluid goes in one end of each tube and out the
other.
APPLICATION:-
o Two fluids, of different starting temperatures,
flow through the heat exchanger.
o One flows through the tubes (the tube side)
and the other flows outside the tubes but
inside the shell (the shell side).
o Heat is transferred from one fluid to the other
through the tube walls, either from tube side to
shell side or vice versa.
o The fluids can be either liquids orgases on
either the shell or the tube side. In order to
transfer heat efficiently, a large heat transfer
area should be used, leading to the use of
many tubes. In this way, waste heat can be
put to use. This is an efficient way to conserve
energy.

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o Heat exchangers with only one phase (liquid
or gas) on each side can be called one-phase
or single-phase heat exchangers.
o Two-phase heat exchangers can be used to
heat a liquid to boil it into a gas (vapor),
sometimes called boilers, or cool a vapor to
condense it into a liquid (called condensers),
with the phase change usually occurring on
the shell side.
o Boilers in steam engine locomotives are
typically large, usually cylindrically-shaped
shell-and-tube heat exchangers.