A heat exchanger is a piece of equipment built for efficient heat
transfer from one medium to another.
They are widely used in space heating, refrigeration, air
conditioning, power plants, chemical plants, petrochemical plants,
petroleum refineries, natural gas processing and sewage
In heat exchangers, there are usually no external heat and work
Common examples of heat exchangers are shell-and-
tube exchangers, automobile radiators, condensers,
evaporators, air preheaters, and cooling towers.
Types Of Heat Exchangers
Double pipe heat exchanger
Shell and tube heat exchanger
Plate heat exchanger
Plate and shell heat exchanger
Plate fin heat exchanger
Spiral heat exchangers
What is a plate type heat exchanger?
It’s a type of Heat Exchanger which consists of many corrugated stainless-
steel sheets separated by polymer gaskets and clamped into a steel frame
•Plate heat exchangers transfer heat by placing thin, corrugated metal sheets
side by side and connecting them by gaskets.
•Flow of the substances to be heated and cooled takes place between
alternating sheets allowing heat to transfer through the metal sheets.
Parts & Their Function
The frame is made up of thick steel
pressure retaining parts, the fixed
cover and the movable cover,
that when pulled together with the
tightening bolts form the pressure
retaining structure for the plates /
plate pack .
The carrying bar and guide bar act
as a carrier and guide to both the
plates and the movable cover
The heat exchanger plates, which make up the heat
transfer surface, are clamped between two plates of
steel with the use of the tightening bolts.
The heat exchanger construction allows a plate heat
exchanger to be easily opened for inspection and
Each plate has a gasket that produces a sealing and
channel system through the entire plate pack in
which the two heat exchanging media flow in a
The circular portion of the gasket stops the fluid from
going across the heat transfer plate and sends it to
the next open channel.
The remaining portion or field gasket directs the
opposing fluid across the heat transfer surface.
4. Flow Arrangement
The heat transfer plates with
gaskets are arranged in an
alternating pattern of left hand
flow and right hand flow to direct
the fluids in an opposing direction
within the heat exchanger.
The completed assembly of all the
plates and gaskets is called the
Why Plate Heat Exchanger?
High heat transfer area
High heat transfer coefficient
Compact and has lower floor space requirements.
By increasing the number of plates the area of heat
exchange can be increased
Most suitable type heat exchangers for lower flow
rates and heat sensitive substances.
Multiple duties can be performed by a single unit
Plate and Frame Heat Exchanger
Most common type of PHE
Consists of plates and gaskets
Materials: stainless steel, titanium and non-metallic
- temperatures from -35°C to 220°C
- pressures up to 25 bar
- flow rate up to 5000 m3/h
Brazed Plate Heat Exchanger
Operates at higher pressures than gasketed units
Materials: stainless steel, copper contained braze
- From -195°C to 200°C
- Pressures up to 30 bar
It is impossible to clean. The only way is by applying chemicals.
Welded Plate Heat Exchanger
Plates welded together to increase pressure and temperature limits
Materials: stainless steal and nickel based alloys. Can be made
with copper , titanium or graphite
- temperature limits depend on the material
- can tolerate pressures in excess of 60 bar
BENEFITS OFFERED BY PLATE HEAT EXCHANGERS
Lightweight: The PHE unit is lighter in total weight than other types of heat exchangers
because of reduced liquid volume space and less surface area for a given application.
High-viscosity applications: Because the PHE induces turbulence at low fluid
velocities, it has practical application for high-viscosity fluids
Saves space and servicing time: The PHE fits into an area one-fifth to one-half of that
required for a comparable shell and tube heat exchanger. The PHE can be opened for
inspection, mainte- nance.
Lower liquid volume: Since the gap between the heat transfer plates is relatively small,
a PHE contains only low quantities of process fluids. The benefit is reduced
cost due to lower volume
Lower cost: PHEs are generally more economical than other types of
equivalent duty heat exchangers due to the higher thermal efficiency and lower
Quick process control: Owing to the thin channels created between the two adjacent
plates, the volume of fluid contained in PHE is small; it quickly reacts to the new
process condition and is thereby easier to control.
LIMITATIONS OF PLATE HEAT EXCHANGERS
The maximum allowable working pressure is also limited by the
frame strength and plate deformation resistance. Commonly stated
limits have been 300°F (149°C) and 300 psi
Because of the narrow gap between the plates, high liquid rates
will involve excessive pressure drops, thus limiting the capacity.
Large differences in fluid flow rates of two streams cannot be
The gaskets cannot handle corrosive or aggressive media.
Gaskets always increase the leakage risk
The standard PHEs cannot handle particulates that are larger than
Particulate fouling or silting
Solid particles are deposited on the heat transfer
Deposition and growth of organism on surfaces
Chemical reaction fouling
Arises from reactions between constituents in the
Freezing or solidification fouling
Occurs when the temperature of a fluid passing
through a heat exchanger becomes too low
Plate heat exchangers are available in a wide variety of
configurations to suit most processes heat transfer
The advantages of PHEs, and associated heat transfer
enhancement techniques, extend far beyond energy efficiency.
Lower capital cost, reduced plant size, and increased safety are
typical of the benefits arising from the use of PHEs.
Plate heat exchangers can replace some normal size heat
exchangers bringing advantages and performance.