Integrated Technical Solutions
PLATE HEAT EXCHANGERS / SERVICE MANUAL
SERVICE MANUAL # 2
TABLE OF CONTENTS
1. Plate Heat Exchanger Basics.............................................................3
2. Construction and Function...............................................................4
3. Gasket Characteristics......................................................................5
4. Flow Patterns and Plates..................................................................6
Diagonal Flow Units.................................................................... 6
Parallel Flow Units....................................................................... 7
5. Opening & Closing of the Unit........................................................8
Opening / Dismantling................................................................. 8
Closing / Re-Assembly.................................................................. 9
Plate Sequencing.......................................................................... 9
Tightening................................................................................. 10
Re-gasketing.............................................................................. 11
6.Maintenance................................................................................. 12
7.Troubleshooting........................................................................... 13
Leakage between plate pack and frame........................................ 13
Leakage between flange and frame.............................................. 14
Leakage between plate pack and frame........................................ 15
Mixing of media......................................................................... 16
Pressure drop problems............................................................... 17
Heat transfer problems............................................................... 18
8. Spare Parts & Support................................................................... 19
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SERVICE MANUAL # 3
1. Plate Heat Exchanger Basics
Heat is transferred from one medium to another through thin metal plates;
having different pattern and design according to maker.
Frame plate
Support column
The two bars are
suspended between
the frame plate –
to which in most cases
the piping is connected
–and a support column.
Carrying bar
Guiding bar
The plates hang from a
carrying bar and are kept
in line by a guiding bar
at the lower end.
Pressure plate
A steel plate called
the pressure plate is also
hung on the carrier bar
and is moveable, as are
the heat transfer plates.
In some cases pipe may
be connected to the
pressure plate.
Connections
Holes matching the piping
lead through the frame plate,
permitting the media to enter
into the heat exchanger.
Threaded studs around the
holes secure the pipes to
the apparatus. Depending
on the application, metallic
or rubber-type linings may
protect the edges of the
holes against corrosion.
Tightening bolts
With the package of thin
plates hanging between the
frame plate and the pressure
plate, a number of tightening
bolts are used to press the
thin plates together, to bring
them into metallic contact,
and to pressure the gaskets,
enough to seal off the
narrow passages which have
now been formed between
the plates.
Channel plates
Gasket
These plates are called
channel plates. A groove
along the rim of the plate
and around the ports hold
a gasket, usually made of
a rubber-type material.
Heat is transferred through
the surface which is
contained by the gasket,
except for some small
areas near the corners.
The number of plates in
the package of your heat
exchanger is determined
by the size of the heat
transfer surface required.
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SERVICE MANUAL # 4
2. Construction & Function
Plates are manufactured in standard sizes in various materials such as stainless steel (304 and 316),
titanium, C276, and SMO-254. The gaskets serve to seal the fluids in the plate-pack and also to
direct the hot and cold media into the proper flow channels. The space between the port gasket
and the perimeter gasket is vented to atmosphere. This ensures that the fluids will never intermix,
and that any leaks will be to the outside of the heat exchanger.
The fluids enter the PHE through connection on the frame. A single pass arrangement has all four
connections on the fixed head. This design is preferred since unit is possible to open for maintenance
or expansion without breaking the pipe connections. For “close-approach” applications, a multipass unit may be required. This arrangement puts connections on both the fixed head and the
moveable follower.
The most common flow pattern is called countercurrent, where the fluid inlets are opposite ends
of the fixed head. The co-current flow pattern is rarely used, but may be a good solution in some
special cases.
Plate Material
• Plate thickness has a variation in the range 0.4-1.0 mm depending from maker/model/application.
• Several alloys are available although, most common is Stainless Steel and Titanium.
• Plates are pressed to form corrugations which increase the surface area and strength of the plates.
• The plate has up to four connection holes for fluid transfer, with gaskets fitted to confine the liquids.
• Maritech engineers can assist you in selecting the proper material for your application.
Thermal Styles
Most makers have designed plates in two thermal styles classified as Type “A” and Type “B”. These
different thermal styles may be used alone or together to tailor the heat transfer and pressure drop
characteristics of the heat exchanger to your specific application.
Different Chevron Αngles
Chevron angles change the fluid dynamics through the heat exchanger.
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SERVICE MANUAL # 5
3. Gasket Design
The Gasket is molded in one piece. The material is normally an elastomer, selected to suit the actual
combination of temperature, chemical environment and possible other conditions that may be present.
2
2
3
The one-piece gasket is composed by:
1. One field gasket
2. Two ring gaskets
3. Links
3
1
The field gasket is by far the larger part containing
the whole heat transfer area and the two corners
connected to it. The ring gaskets seal off the
remaining two corners.
1
3
3
2
2
Diagonal Flow Gasket
These three pieces are held together by a few
short links, which have no sealing function at all.
Their purpose is simply to tie the pieces together
and to add some support in certain areas.
On some plate heat exchangers, the gasket is
held in place on the plate by means of a suitable
cement or glue.
Parallel Flow Gasket
TABLE WITH ELASTOMER TYPES
Elastomer
FDA
NF
1994
3-A
PZH
Colour
Colour
Mark
NBR
































































black
2 yellow
10-25
black
1 yellow
10-25
NBR
EPDM
HNBR
HNBR
FKM A
FKM A
FKM B
FKM GF
IIR
IIR
CSM
CR
NAT
PUM
SIC
DRC 24h at 150°C DRC 36h at 150°C
on gaskets
on gaskets
Shore A
hardness
T °C
70% max
73 ± 5
-10/ +130
70% max (at 100°)
80 ± 5
-10/ +110
black
1 blue
10-20
55% max
80 ± 5
-5/ +140
black
1 green
10-20
55% max
80 ± 5
-10/ +155
noir
2 green
10-20
55% max
75 ± 5
-10/ +150
noir
2 purple
10-20
30% max
75 ± 5
-5/ +200
black
1 purple
10-20
20% max
80 ± 5
-5/ +200
black
2 brown
10-20
30% max
80 ± 5
-5/ +200
black
2 beige
10-20
35% max
80 ± 5
-5/ +200
black
1 white
10-30
80% max
80 ± 5
-5/ +110
black
2 white
10-30
55% max
75 ± 5
-5/ +150
1 red
35% max (at 70°)
55% max (at 70°)
80 ± 5
-5/ +125
black
1 dark green 15% max (at 100°) 40% max (at 100°)
80 ± 5
-20/ +100
black
Small pieces
60 ± 5
-50/ +70
black
Small pieces
95 ± 5
-30/ +120
red
Small pieces
80 ± 5
-80/ +250
black
Gaskets are available in all common elastomers including Nitrile, EPDM, RCB, Viton®, etc.
Maritech engineers can assist you selecting the right material for your application.
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SERVICE MANUAL # 6
4. Flow Patterns
In heat exchanger design, there are three types of flow arrangements: counter-flow, parallel-flow,
and cross-flow. In the counter-flow heat exchanger, both fluids entered the exchanger from opposite
sides. In the parallel-flow heat exchanger, the fluids come in from the same end and move parallel to
each other
as they flow to the other side. The cross-flow heat exchanger moves the fluids in a perpendicular
fashion. Compare to other flow arrangements counter –flow is the most efficient design because
it transfers the greatest amount of heat.
Diagonal Flow Units
A-plate
B-plate
An A-plate
is a plate hanging
with the chevron
pointing downwards
A B-plate
is a plate hanging
with the chevron
pointing upwards
If we change the gasket and turn an A-plate upside down we will have a B-plate.
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SERVICE MANUAL # 7
Parallel Flow Units
A-plate
B-plate
An A-plate
is a plate hanging
with the chevron
pointing downwards
A B-plate
is a plate hanging
with the chevron
pointing upwards
If we turn an A-plate upside down we will have a B-plate.
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SERVICE MANUAL # 8
5. Opening & Closing of the unit
Opening / Dismantling
• Before dismantling the unit, verify and record the compressed tightening dimension of
the plate pack.
• Before opening the heat exchanger, make sure that both sides are gradually lowered to
atmospheric pressure.
• The temperature should be allowed to fall to ambient to avoid loosening the gaskets.
• Loosen the tightening bolts. The moving frame can now be pulled back towards the column,
thus exposing the plate pack.
• The plates should be removed one by one, if required.
• Dismantling of the plate pack must be carried out with great care. If not already done, number
the plates before taking them out. To remove a plate from the frame, lift and tilt to an angle
until it can be removed. If desired, the plates can be cleaned or inspected one by one while
separated in the frame, and need not be removed.
• Before re-assembly, make sure that all plates and gaskets are wiped clean and free from dirt.
Solid particles adhering to the gaskets can cause damage and may also result in leakage when
the unit is put back in operation.
• Upon completion of cleaning and final inspection of each plate, the unit may be closed
and tightened.
• Never allow the pressure plate to be at an angle to the plate pack as the plates maybe
distorted, due to excessive loading.
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SERVICE MANUAL # 9
Closing / Re-Assembly
The first plate is the “A” plate followed by a “B” plate, until all plates are hanging in the frame.
Re-assemble the unit in the opposite sequence of disassembling see bolt tightening sequence below.
Hang the plates with their backs towards
the pressure plate (the side without gasket)
Plate Sequencing
• Always refer to the production drawing when assembling the plate pack. All plates must go back in
the same order they came out.
• If plates are alternated properly, a honeycomb pattern should be evident on the sides of the plates.
CORRECT
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INCORRECT
SERVICE MANUAL # 10
Tightening
• Push moveable follower to contact rear of plate pack.
• Install tightening bolts and nuts.
• Starting with the center bolts, tighten using hand tools. It is important to keep the follower
parallel to the fixed head during the entire tightening operation.
• When the required measurement has been reached at the center of the pack, continue tightening
the bolts out from the center. Do not tighten any particular bolt more than ½” at a time. Continue
until frame is parallel and tightened to no more that the recommended tightening measurement.
The recommended tightening measurement is
a minimum value which should not be exceeded.
Permanent plate deformation may occur if
the pack is over tightened.
Check the dimensions A during tightening at
the positions of the bolts which are being used.
Skewing of the pressure plate during tightening
must not exceed 10 mm (2 turns per bolt) across
the width and 25 mm (5 turns per bolt) vertically.
STOP IMMEDIATELY if you notice that the plates
are shifting, the gaskets are not sealing properly,
or the follower and terminals are not moving
freely. Open the unit and correct the problem
Nominal plate pack length A can be exceeded in
exceptional cases, the tightening can be stopped
at the following dimensions:
NOTE!
When a pneumatic device is used, it
should be set at the maximum torque
according to below table. Dimension A,
still to be measured during tightening.
Plate pack length/plate
Plate pack length/plate
>4 mm
A + 1%
>3 mm, <4 mm
A + 1,5%
<3 mm
A + 2%
If unit does not fully seal, it can be tightened
to give dimensions A -1%. However, the max
tightening torque must not be exceeded.
If dimension A is not reached with application
of maximum tightening torque:
Bolt size
Bolt with bearing box
Bolt with washers
Nm
Kpm
Nm
Nm
M24
–
–
450
45
M30
–
–
900
90
M39
1300
130
2000
200
M48
2100
210
3300
330
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• Check the number of plates and dimension A.
• Check that all the nuts and bearing boxes
are running freely. If not, clean and lubricate
or replace.
If you encounter any problems, please contact
Maritech service engineers.
SERVICE MANUAL # 11
Re-gasketing
For Glued-type elastomers
• Remove the old gasket from the gasket groove.
• If the gasket does not come out easily, use mild heat on the back of the plate.
• Remove with care all of the old glue in the gasket groove.
• Apply a thin coat of glue in the gasket groove.(Recommended adhesives are 3M1099, or
factory-approved equal)
• Press gasket into place, starting at the ends and working towards the middle of the plate.
• Stack the plates horizontally and put a heavy weight on top of the stack.
• Leave staked for a approximately 12 hours before reinstating.
For Clip–on type elastomers (glue–free)
• The Clip–on gasket is attached to the plate by two gasket prongs which slip under the edge
of the plate to hold the gasket securely in alignment in the gasket groove.
• The prongs are situated at regular intervals around the periphery of the plate.
• When the plate heat exchanger is then assembled and tightened, the gasket provides a tight
seal around the plate.
Tips
Gaskets should be replaced immediately if found to hard and shiny, brittle, or are eroding away.
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SERVICE MANUAL # 12
6. Maintenance Services
Depending on the operating conditions of the heat exchanger, plates will need to be re-gasketed
and/or replaced. The maintenance of plate heat exchangers requires a complete and deep experience
and expertise.
Maritech service engineers follow a strict process to ensure accuracy, quality and warrant the highest
service level offering complete services for cleaning, leak testing, regasketing, or repairing your
entire unit.
Maritech in-situ Recondition Cycle:
•Inspection
• Removal of Gaskets
• Chemical Cleaning
• Deformation Maintenance
• Crack Detection by UV
• Re-gasketing
• Hydraulic Testing
NOTE!
If any signs of liquid to liquid crossover are observed, or if any plates
are suspected to leak, they should
be professionally inspected for leaks.
Most leaks occur at small pinholes
or cracks that are almost always
impossible to see with the naked eye.
Maritech Re-gasketing services
We are a specialized company dedicated to manufacture, supply and maintenance of plate heat exchangers.
Our service includes removal of old gaskets and chemical cleaning of plate’s groove, Crack detection
by UV and, regasketing using a proven adhesive.
Maritech Rotation / Service Plate Packs
If the majority of the plates in your heat exchanger need to be serviced, it may be advantageous for you
to get benefitted through a rotation plate pack. With this option, you receive new or reconditioned plates
ready for plug & play installation elimination any downtimes.
The replacement plates are installed and old plates are returned back to our service station.
If any plate found heavy damaged and beyond repair then, will be excluded from further process.
At the end of the process, your repaired plates will be ready to cover your next fleet inquiry.
Through our Rotation scheme of plate packs within fleet, owners are enabled to:
• Reduce significally costs
• Minimize downtimes
• Obtain a true view on unit’s condition
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SERVICE MANUAL # 13
7. Troubleshoot
Troubleshooting is an abstract based on best practices of various makers.
Leakage between plate pack and frame
Action
Correction
Mark the area were the leakage seems to be,
and open the heat exchanger.
• Relocate the gasket.
• Remove foreign matter.
• Replace damaged gasket.
• Replace connection lining if applicable.
1. Investigate the gasket condition of the end
plate and the connection if applica- ble, look
for dislocation, foreign objects, scars and other
damage to the gasket surfaces.
2. Check the surface of the pressure plate for
unevenness, foreign objects sticking to it, etc.,
which might spoil the joint between the gasket
and the adjacent surface.
3. Check the plate itself for cracks or holes.
4. A perforated end plate must be replaced.
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Remove anything disturbing the joint between
gasket and pressure plate surface.
SERVICE MANUAL # 14
Leakage between flange and frame
Action
Correction
Disconnect the flange, and look for misalignment
between flange and connection, dislocation or
damaged gasket, foreign objects on the surface
of the gasket or the flange.
• Rearrange the pipe in order to eliminate
stress and to correct alignment.
• Relocate gasket.
• Replace damaged gasket.
• Replace connection lining if applicable.
• Remove foreign matter from flange
and gasket.
• Reassemble, taking care to avoid
misalignment.
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SERVICE MANUAL # 15
Leakage between plate pack and frame
NOTE!
On a Plate Heat Exchanger specially
designed for high temperature duties,
extreme and sudden temperature drops
may sometimes cause a temporary
leakage. A typical example is a sudden
shutting–off of the hot medium flow.
The heat exchanger will normally seal
again, as soon as the temperatures of
the apparatus have stabilized.
Action
Correction
Mark the leakage area on the two plates next to
the leakage, check and note the length of the plate
pack between inside frame plate and inside pressure
plate, and then open the heat exchanger.
1. • Relocate the gasket.
• Re-cement loose gasket.
• Replace damaged gasket.
1. Check for loose, dislocated or damaged gasket.
2. Check for plate damage in the area, and also
check plate pack length against drawing to see
if possible plate or gasket damage could be
caused by over–tightening of the plate pack, or
the leakage itelf simply be caused by insufficient
tightening.
3. Check hanger recess at both plate ends for
deformations, which could cause misalignment
between the plates.
4. Make sure that the plates are hanging correctly.
5. Check plates for corrosion.
2. A damaged plate must in most cases be taken out
for repair or replacement. If it is a reg-ular plate
with 4holes: take the damaged plate and the 4–hole
plate just in front or just behind it out of the plate
pack. The heat ex- changer can now be reassembled
and put back in service Provided the plate pack is
tightened to a new measurement, which is equal
to the one on the drawing, reduced by two times
the space required per plate.
The small reduction of the heat transfer area is
normally of no importance, at least not for a short
period of time.
Insufficient tightening must be corrected
(see the drawing).
3. Damaged hanger recesses must be repaired if
possible, or the plate replaced. For temporary
arrangement with reduced number of plates
(see paragraph 2 above).
4. Incorrect sequence of plates must be corrected.
Make sure that no plate has been damaged, before
re-assembling the plate pack.
5. Corroded plates must be replaced.
For temporary solution, see paragraph 2.
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SERVICE MANUAL # 16
Mixing of media
Action
Correction
1.Check that the piping is connected to the heat
exchanger at correct locations.
1.Relocate piping to correct connections.
2.Open the lower connection on one side, raise
pressure on the other side and by looking into
the open connection try to detect any liquid
from the pressurized side leaking in, and if so
approximately how far into the plate pack
the leakage is located.
If no leakage is detected, the reason for the
mixing of media must be sought else- where.
(See paragraph 5).
3.If a leakage was detected, note the position of
the leakage along the plate pack and then open
the plate heat exchanger.
4.Before starting on the plates themselves, check
that the corner areas between the ring and the
field gaskets are clear, that the leakage slots
are open. This ensures that any leakage is out of
the plate heat exchanger and is to atmosphere.
Therefore no pressure can build up to force
the media across the gasket sealing off the
other liquid.
4.All deposits or material which can block the free
exit from the area must be removed. If the leak
channels of the gasket have been destroyed, they
must be reopened with a suitable tool, or the gasket
replaced.
5.If it has not been possible to locate the leakage
as described in paragraph 2 above, it will
be necessary to check each single plate for
possible perforations, using any of the following
methods:
– put a strong light behind the plate and watch for
light coming through fine holes or cracks
– use a magnifying glass to check suspect area
– use a chemical penetrant, after having cleaned
the plates well.
5.Plates found with holes should be replaced.
For temporary solution with reduced number of
plates, see “Leakage between plates to the outside”.
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SERVICE MANUAL # 17
Pressure drop problems
Pressure drop has increased.
Action
Correction
Check that all valves are open including non
return valves.
Measure the pressure just before and just after
the heat exchanger, and the flow rate. For viscous
media a membrane manometer with a diameter of
at least 30 millimeters should be used. Measure
or estimate the flow rate if possible. A bucket and
a watch showing seconds may be sufficient for
small flow rates. For larger flow rates, some type
of flowmeter is required.
Compare the pressure drop observed with the one
specified for the actual flow rate.
(See data print out).
1.If the pressure drop is higher than specified, the
temperature program should also be checked:
1.1. If the thermometer readings correspond to
those specified, the heat transfer sur- face is
probably clean enough, but the inlet to the heat
exchanger may be clogged by some objects.
1.2. If the thermometer readings are NOT
corresponding to the specified, heat transfer
is obviously dropping below specifications,
because of deposits on the heat transfer surface,
which at the same time also increase the pressure
drop, since the passage becomes nar- rower.
1.See next paragraph.
1.1. Open the apparatus and take out whatever is
clogging the passage, or use the back– flush system
if there is one to rinse out the clogging.
1.2. If not, open the apparatus and clean the plates.
2.If the pressure drop is corresponding to the
specifications, there is no need for any action.
3.If the pressure drop is lower than specified, the
pump capacity is too small or the observation
is wrong.
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3.See pump instruction manual.
SERVICE MANUAL # 18
Heat transfer problems
The heat transfer capacity is dropping.
Action
Correction
Measure temperatures at inlet/outlet and – also
flow rates – on both media, if pos- sible. At least
on one of the media, both temperatures and the
flow rate must be measured.
Check to see if the transferred amount of heat
energy corresponds to the specifications.
If great precision is important, it will be necessary
to use laboratory thermometers with an accuracy
of 0.1 degree Celsius, and also to use the best
equipment available for flow measurement.
If the heat transfer capacity of the apparatus has
dropped below specified values, the heat transfer
surface, must be cleaned. Either use the “cleaning–
in– place” arrangement provided or open the heat
exchanger for visual inspection and manual cleaning.
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SERVICE MANUAL # 19
8. Spare Parts & Support
Having a deep knowledge of heat exchangers, we maintain an accurate database to support
and ensure accuracy of our deliveries.
Ask your plate heat exchanger representative for detailed part numbers for your particular unit.
Support
Maritech team is aparted from experienced stuff, who can understand and meet each specific needs,
providing promptly a reliable solution.
Support Overview
• Preventative Maintenance
• Spare Parts and Consumables
• Troubleshooting
• Technical Support
Additional Services
Maritech designs the right solutions to fit different needs with focus on developing “how to” guides
that help crew diagnose, prevent and resolve several issues independently onboard.
• Assy instructions
• Tightening measurements
• Operational tips
• In-situ / Onboard technical support
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