Instruction Manual - Brazed plate heat exchangers EN FR DE

EN
FR
Instruction Manual - Brazed plate heat exchangers
DE
Tantalum line TA30, TA60, TA112
SV
JA
34567071-01-EN 2014-07
Original manual
Table of contents
Description ...................................................................................................
Definitions ...............................................................................................
Main components ......................................................................................
Function .................................................................................................
Name plates .............................................................................................
5
5
6
7
8
Installation ...................................................................................................
Unpacking ...............................................................................................
Lifting .....................................................................................................
Requirements ...........................................................................................
Pipe spools and piping system .......................................................................
Installation in general ..................................................................................
10
10
10
11
11
13
Operation ....................................................................................................
Start-up ..................................................................................................
Unit in operation ........................................................................................
Shut-down ...............................................................................................
14
14
15
16
Maintenance .................................................................................................
General guidelines regarding maintenance .........................................................
Cleaning-In-Place ......................................................................................
Cleaning liquids .........................................................................................
17
17
18
19
Fault tracing .................................................................................................
Pressure drop problems ...............................................................................
Heat transfer problems ................................................................................
20
20
20
EN
How to contact Alfa Laval
Contact details for all countries are
continually updated on our website.
Please visit www.alfalaval.com to access the information directly.
© Alfa Laval Corporate AB
This document and its contents is owned by Alfa Laval Corporate AB and protected by laws governing intellectual property and
thereto related rights. It is the responsibility of the user of this document to comply with all applicable intellectual property laws.
Without limiting any rights related to this document, no part of this document may be copied, reproduced or transmitted in any
form or by any means (electronic, mechanical, photocopying, recording, or otherwise), or for any purpose, without the expressed
permission of Alfa Laval Corporate AB. Alfa Laval Corporate AB will enforce its rights related to this document to the fullest
extent of the law, including the seeking of criminal prosecution.
Document ID
Language
34567071-01 EN
Edition
2014-07
Instruction Manual - Brazed plate heat exchangers
3
Preface
Preface
This manual provides information needed to install, operate
and carry out the maintenance of the plate heat exchanger.
Intended use
The plate heat exchanger has been designed to perform
heat transfer to meet the requirements of a wide range of
applications within the process industry with exceptionally
aggressive media.
heat exchanger. Alternatively, the warranty conditions
are included in the sales offer documentation or with a
reference to the document specifying the valid conditions.
If faults occur during the specified warranty period, always
consult your local Alfa Laval Representative for advice.
Report the date when the plate heat exchanger was put into
operation to the local Alfa Laval Representative.
Safety considerations
Storage of the plate heat exchangers
The plate heat exchanger shall be used and maintained in
accordance with Alfa Laval’s instructions in this manual.
The faulty handling of the plate heat exchanger may result
in serious consequences with injuries to people and/or
property damage. Alfa Laval will not accept responsibility
for any damage or injury caused as a result of not following
the instructions in this manual.
Alfa Laval delivers the plate heat exchanger ready to be
put into operation upon arrival, unless agreed otherwise.
Keep the plate heat exchanger in the packing box until it is
ready to be installed.
Regarding storage for longer periods of time, one month or
more, certain precautions should be made to avoid any
unnecessary damage to the plate heat exchanger.
The plate heat exchanger shall be used in accordance
with the specified configuration of material, media types,
temperatures and pressure for the specific plate heat
exchangers.
Note!
Alfa Laval and its Representatives reserve the right
to inspect the storage space and/or equipment
whenever necessary until the expiry of the warranty
period stipulated in the contract. Notification will be
provided 10 days prior to the date of inspection.
Prior knowledge
The plate heat exchanger shall be operated by people
who have studied the instructions in this manual and have
knowledge of the process. This also includes knowledge
of the precautions regarding media type, pressures, the
temperatures in the plate heat exchanger as well as specific
precautions required for the process.
The maintenance and installation of the plate heat
exchanger shall be performed by people who have
knowledge and authorisation according to the local
regulations. This may include actions such as piping,
welding and other kinds of maintenance.
For maintenance actions not described in this manual,
please contact an Alfa Laval Representative for advice.
Definitions of expressions
Warning!
Type of hazard
WARNING indicates a potentially hazardous
situation that, if not avoided, may result in death or
serious injury.
If there is any uncertainty with regard to the storage of
the plate heat exchanger, please consult an Alfa Laval
Representative.
Environmental compliance
Alfa Laval endeavours to perform its own operations
as cleanly and efficiently as possible, and to take
environmental aspects into consideration when developing,
designing, manufacturing, servicing and marketing its
products.
All the plate heat exchangers in the Tantalum line use
recycled tantalum only.
Unpacking
Packing material consists of wood, plastics, cardboard
boxes and, in some cases, metal straps.
•
•
Caution!
Type of hazard
CAUTION indicates a potentially hazardous
situation that, if not avoided, may result in minor
or moderate injury.
Note!
NOTE indicates a potentially hazardous situation
that, if not avoided, may result in property damage.
Warranty conditions
•
Wood and cardboard boxes can be reused, recycled or
used for energy recovery.
Plastics should be recycled or burnt at a licensed waste
incineration plant.
Metal straps should be sent for material recycling.
Maintenance
• All metal parts should be sent for material recycling.
Scrapping
At the end of its service life, the equipment shall be recycled
according to the relevant, local regulations. Besides the
equipment itself, any hazardous residues from the process
liquid must be dealt with in a proper manner. If in doubt, or
in the absence of local regulations, please contact the local
Alfa Laval sales company.
The warranty conditions are usually included in the signed
sales contract prior to the order of the delivered plate
Document ID
4
Instruction Manual - Brazed plate heat exchangers
Language
34567071-01 EN
Edition
2014-07
Description
EN
Description
Definitions
Tantalum line
The basic construction is a copper brazed heat exchanger with one channel treated with
tantalum that is metallurgically bonded to all surfaces of the channel. The tantalum layer makes
it very resistant to highly corrosive media and it can withstand high temperatures. The other
channel is a regular copper brazed channel.
Heat transfer area
The area of one plate which is in contact with both fluids.
Total heat transfer area
The total surface area of all plates, which are in contact with both fluids.
Plate
A sheet of 100% stainless steel plate pressed into a corrugated pattern and equipped with
port holes for media inlet and outlet.
Plate pack
An assembly of plates brazed together to a plate pack with internal channels in which two fluids
can be handled. One of the channels is treated with tantalum.
Port
Inlet or outlet opening in the plates and in the cover plates. Most plates have four ports.
Connections
The plate heat exchanger is equipped with two connection plates. The pipe spools must be
mounted after delivery, refer to “Mounting of pipe spools” on page 12 for instructions on how
to attach the pipe spools to the connection plates with bolts. The two straight pipe spools are
tantalum treated and the bent pipe spools are made of stainless steel.
Document ID
Language
34567071-01 EN
Edition
2014-07
Instruction Manual - Brazed plate heat exchangers
5
Description
Main components
Bear in mind that the plate heat exchanger cannot be opened!
7
S4
S1
5
3
4
1
2
5
1
2
6
S3
S2
Figure 1. Plate heat exchanger components.
1
Pipe Spools
Process side
Connection S3 and S4. Equipped with stainless steel fittings with a
tantalum layer on all surfaces exposed to corrosive media, permitting
the media to enter into the plate heat exchanger.
2
Pipe Spools
Utility side
Connection S1 and S2. Equipped with stainless steel fittings,
permitting the media to enter into the plate heat exchanger.
3
Seal
Keeping the media within the unit
4
Cover plate
Front and rear cover plates to protect the channel plates and maintain
the design pressure.
5
Connection
plate
The connection plates are located between the pipe spools and the
plate heat exchanger. The pipe spools are not attached at delivery,
refer to “Mounting of pipe spools” on page 12 for instructions on how
to attach the pipe spools to the connection plates with bolts.
6
Support
Support for the plate heat exchanger for floor mounting. The design
can be different depending on the model.
7
Lifting device
Attachment used to lift the plate heat exchanger. The design can be
different depending on the model.
The pipe spools on the process side have a tantalum layer on the inside of the pipes, the contact
surface of the flange and the contact surface attached to the connection plate.
Caution!
Make sure that the tantalum layer in the connections is not damaged when attaching the
pipe spools to the connection plate, or when connecting or disconnecting the flanges to
or from the pipe system on the process side.
Document ID
6
Instruction Manual - Brazed plate heat exchangers
Language
34567071-01 EN
Edition
2014-07
Description
EN
Function
Plate heat exchangers consist of a pack of corrugated metal plates with ports for the passage of
the two fluids between which the heat transfer will take place.
The media in the heat transfer are led into the plate pack through portholes at the corners and
are distributed into the passages between the corrugated plates.
The heating surface consists of thin corrugated plates stacked on top of each other. In the
brazing process at high temperatures, channels are formed between the plates and corner ports
are arranged so that the two media flow through alternate channels, normally in counter-current
flow. The contact points are also brazed to withstand the pressure of the media handled.
The Tantalum line plate heat exchanger is typically used for hot and highly corrosive media.
A specific plate heat exchanger is dimensioned for a specific duty, set out in the product
documentation, and should not be used in any other way without consulting the supplier.
One of the channels in the plate heat exchanger has a tantalum layer to withstand different
aggressive solutions.
Warning!
If the plate heat exchanger is intended to be used for cyclic processes, please contact
an Alfa Laval Representative for advice.
1
4
3
2
Figure 2. Function: Cover plate (1), corrugated plates (2), seal (3) and ports (4).
Document ID
Language
34567071-01 EN
Edition
2014-07
Instruction Manual - Brazed plate heat exchangers
7
Description
Name plates
Warning!
For each unit, the mechanical design pressures and temperatures are marked on the
name plate. These must not be exceeded.
The type of unit, manufacturing number and manufacturing year can be found on the name plate.
Pressure vessel details in accordance with the applicable pressure vessel code are also stated.
The name plate is fixed to the cover plate (most often on the same side as the connections).
Note!
Other types of name plate may be used. For detailed information, please contact an
Alfa Laval Representative.
Some specifications are not used for all types of name plate
Different name plates exist depending on the type of pressure vessel approval.
A
B
10
10
1
2
3
13
4
8
17
18
5
6
7
19
9 & 12
1 & 12
15
16
13
14
3
11
9
11
Document ID
8
Instruction Manual - Brazed plate heat exchangers
Language
34567071-01 EN
Edition
2014-07
Description
EN
Name plate types
A. PED Stainless steel
B. ASME, Stainless steel
Descriptions of name plate fields
1. Manufacturer's name
2. Article number
3. Type
4. Date of manufacture
5. Max. allowed operating temperatures
6. Max. allowed operating pressures
7. Test pressure
8. Fluid group
9. Information unique to the customer
10. Space for logotype
11. Possible locations of connections (Sketch on name plate showing possible locations of
connections depending on heat exchanger execution).
12. Space for mark of approval
CE-409 BHE Manufacturing, Ronneby, Sweden
13. Serial number
14. Manufacturing year
15. Max. allowed working pressures at temperature
16. Max. allowed medium temperature at max. allowed working pressure
17. Reference to construction standard
18. Port combination for each channel
19. Total volume (Litre)
Identification plate for pipe spools
[INFO]
[NUMBER]
[CODE]
INFO
Pipe spools for the tantalum treated channel are marked TANTALUM SIDE.
NUMBER
Article number
CODE
Pressure Piping code
Document ID
Language
34567071-01 EN
Edition
2014-07
Instruction Manual - Brazed plate heat exchangers
9
Installation
Installation
Unpacking
Check that all items are included according to the
specifications and that all parts are undamaged.
Lifting
Warning!
Never lift by the connections or the studs around them. Straps should be used when
lifting. Place straps according to figure below.
0
Figure 3. The lifting of the plate heat exchanger.
Document ID
10
Instruction Manual - Brazed plate heat exchangers
Language
34567071-01 EN
Edition
2014-07
Installation
EN
Requirements
Warning!
The plate heat exchanger must be installed and operated in such a way that no risk of
injury to personnel or damage to property will be incurred.
Caution!
Protective gloves should always be worn when handling the plate heat exchanger to
avoid hand injuries caused by sharp edges.
Warning!
With two different kinds of channel, it is highly important to make sure that each channel
is connected to the correct media during installation.
Warning!
The Tantalum plate heat exchanger is intended to be used for highly corrosive fluids.
Safety rules for handling such fluids should be followed.
Foundation
Install on a flat foundation giving enough support to the unit.
Pipe spools and piping system
Note!
The plate heat exchanger is approved according to the specified pressure vessel code.
The pipe spools are attached as part of the piping system.
S4
S1
S2
S3
Figure 4. S3 and S4 are the connections for the channels with a tantalum layer.
Document ID
Language
34567071-01 EN
Edition
2014-07
Instruction Manual - Brazed plate heat exchangers
11
Installation
Mounting of pipe spools
The plate heat exchanger is delivered with pipe spools that need to be attached before the plate
heat exchanger is connected to the rest of the piping system. Follow the instruction below for
attaching the pipe spools to the plate heat exchanger.
Step 1
Four pipe spools are delivered with the plate heat exchanger.
Step 2
Identify the two straight pipe spools with the tantalum layer and
make sure that those connections are handled carefully without
damaging the tantalum layer on the flange surfaces or inside the
pipe. Refer to Identification plate for pipe spools on page 9 .
Step 3
It is extremely important to make sure that the straight pipe
spools are positioned at the tantalum treated channel at
connections S3 and S4 on the connection plate.
Step 4
The straight pipe spools are tantalum treated and are used for
position S3 and S4. Remove the protective material from all
connection surfaces. Also, make sure that all dust and other
particles are removed before attaching the pipe spools. Place
the gasket according to the picture at port S3 and attach the
pipe spool with the bolts. Repeat for the other straight pipe
spool at port S4.
Caution!
If the mounting of pipe spools is performed on a standing
plate heat exchanger, make sure that the plate heat
exchanger is well supported to stop it from tipping over.
Caution!
Make sure that the bolts are firmly and evenly tightened!
Step 5
The bent pipe spools are not tantalum treated and are used for
position S1 and S2. Remove the protective material from all
connection surfaces. Also, make sure that all dust and other
particles are removed before attaching the pipe spools. Place
the gasket according to the picture at port S2 and attach the
pipe spool with the bolts. Repeat for the other bent pipe spool
at port S1.
Step 6
Perform a leakage test before installing the plate heat exchanger
to the rest of the piping system.
Document ID
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Instruction Manual - Brazed plate heat exchangers
Language
34567071-01 EN
Edition
2014-07
Installation
EN
Connect to piping system
Caution!
One channel has a tantalum layer and it is extremely important to make sure that this
channel is used for the correct media.
Note!
Before connecting any piping, make sure all foreign objects have been flushed out
of the system.
When connecting the plate heat exchanger to the piping system, make sure that no tension
and loads are transferred to the plate heat exchanger. Also, make sure that vibrations are
eliminated or reduced to a minimum level.
Caution!
Make sure that the tantalum layer in the connections is not damaged when connecting
or disconnecting the flanges to or from the pipe system on the process side.
Warning!
Depending on which fluids are used, install proper equipment for the collection of
residuals from the vent valve and the drain, respectively.
Installation in general
Warning!
Safety valves should be installed according to pressure vessel regulations.
The installation must be provided with equipment that protects the plate heat exchanger against
pressures and temperatures outside the approved minimum and maximum values shown on
the name plate.
For the best possible heat transfer performance, the plate heat exchanger should be connected
so that the media flow through the plate heat exchanger in opposite directions (in counter-current
flow).
Document ID
Language
34567071-01 EN
Edition
2014-07
Instruction Manual - Brazed plate heat exchangers
13
Operation
Operation
Start-up
Warning!
Make sure that the installation has been properly carried out to ensure safe operation.
Refer to Installation on page 10.
Note!
If several pumps are included in the system, make sure you know which one should be
activated first.
Note!
Adjustments of flow rates should be made slowly in order to avoid the risk of water
hammer.
Water hammer is a short-lasting pressure peak that can appear during start-up or
shut-down of a system, causing liquids to travel along a pipe as a wave at the speed of
sound. This can cause considerable damage to the equipment.
Step 1
Check that the inlet valve (2) is closed between the pump and
the unit controlling the system flow rate.
Inlet valve (2, 3) for both fluids should be closed, the outlet
valves (1, 4) opened and the vent valve (5) closed.
1
5
1
2
3
42
Step 2
If there is a outlet valve (4), make sure that it is fully open
4
Step 3
Open the vent valve (5) and start the pump.
5
3
Step 4
Open the inlet valve (2) slowly.
2
3
Document ID
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Instruction Manual - Brazed plate heat exchangers
Language
34567071-01 EN
Edition
2014-07
Operation
Step 5
When all air is expelled, close the vent valve (5).
5
EN
4
Step 6
Repeat steps 1–5 for the second media.
Unit in operation
Note!
Adjustments of flow rates should be made slowly in order to protect the system against
sudden and extreme variations of temperature and pressure.
During operation, check that:
•
•
media temperatures and pressures are within the limits stated on the name plate
no leakages appear due to faulty tightening of the connections.
Protection against freezing
Bear in mind the risk of freezing at low temperatures. Plate heat exchangers that are not in
operation should be emptied and blown dry whenever there is a risk of freezing.
Protection against clogging
Use a filter as protection against the possible occurrence of foreign particles. If you have any
doubt concerning the maximum particle size, please consult your Alfa Laval Representative.
Document ID
Language
34567071-01 EN
Edition
2014-07
Instruction Manual - Brazed plate heat exchangers
15
Operation
Protection against thermal or/and pressure fatigue
Sudden temperature and pressure changes could cause fatigue damage to the heat exchanger.
Therefore, the following must be taken into consideration to ensure that the heat exchanger
operates without swinging pressures/temperatures.
•
•
•
•
Locate the temperature sensor as close as possible to the outlet from the heat exchanger
Choose valves and regulation equipment which give stable temperatures/pressures for
the heat exchanger.
To avoid water hammer, quick-closing valves must not be used, e.g. on/off valves.
In automated installations, the stopping and starting of pumps and actuation of valves should
be programmed so that the resulting amplitude and frequency of the pressure variation
will be as low as possible.
Protection against corrosion
The process side has a tantalum layer and is suitable for most strong acids, including, for
example, sulphuric acid and hydrochloric acid. The complete list of fluids that can be used
is available on www.alfalaval.com/tantalum or, alternatively, please contact your Alfa Laval
Representative.
The utility side consists of stainless steel and copper, and fluids that are aggressive to these
materials must not be used.
Shut-down
Note!
If several pumps are included in the system, make sure you know which one should be
stopped first.
1.
2.
3.
4.
Slowly reduce the flow rate in order to avoid water hammer.
When the valve is closed, stop the pump.
Repeat steps 1–2 for the other medium/media.
If the plate heat exchanger is shut down for a long period, it should be drained.
Draining should also be done if the process is shut down and the ambient temperature is
below the freezing temperature of the media.
Depending on the media processed, it is also recommended to rinse and dry the heat
exchanger and its connections.
Document ID
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Instruction Manual - Brazed plate heat exchangers
Language
34567071-01 EN
Edition
2014-07
Maintenance
EN
Maintenance
General guidelines regarding maintenance
Caution!
With two different kinds of channel, it is highly important to make sure that correct
cleaning methods and solutions are used for each channel.
If cleaning is required, the only chemical cleaning method that should be used is
Cleaning-In-Place (CIP).
Process side
When operating with strong acids, the cleaning of the tantalum treated side is normally not
required. Should cleaning be needed, then circulate with hot water. In case this is not sufficient,
please contact your Alfa Laval Representative for advice. Alkaline solutions should (normally)
not be used for the cleaning of the process side with the tantalum layer.
Caution!
Avoid alkaline cleaning solutions for the process side with the tantalum layer. If you are
considering using alkaline cleaning, please contact your Alfa Laval Representative.
Utility side
Depending on the media used on the utility side, different types of cleaning liquid may be
needed. Refer to “Cleaning liquids” on page 19 for detailed information.
Caution!
Under no circumstances should hydrochloric acid be used with stainless steel plates.
Note!
Rinse well!
Chlorine as a growth inhibitor
Note!
Chlorine, commonly used as a growth inhibitor in cooling water systems, reduces the
corrosion resistance of stainless steels.
Chlorine weakens the passive layer of these steels making them more susceptible to
corrosion attacks than they otherwise would be. It is a matter of the time of exposure
and the concentration.
In every case where the chlorination of the plate heat exchanger cannot be avoided, your local
Alfa Laval Representative must be consulted.
Caution!
Make sure that the handling of residuals after using cleaning liquids follows the local
environmental regulations.
Document ID
Language
34567071-01 EN
Edition
2014-07
Instruction Manual - Brazed plate heat exchangers
17
Maintenance
Cleaning-In-Place
The Cleaning-In-Place (CIP) equipment permits cleaning of the plate heat exchanger.
CIP performs:
•
•
•
cleaning of fouling and descaling of lime deposits
passivation of cleaned surfaces to reduce the susceptibility to corrosion after acid cleaning
neutralisation of cleaning liquids before draining.
Follow the instructions of the CIP equipment.
The following CIP models can be used: CIP20, CIP40 and CIP200L.
Warning!
Use proper protective equipment, such as safety boots, safety gloves and eye protection,
when using the cleaning agents.
Warning!
Corrosive cleaning liquids can cause serious injuries to skin and eyes!
Document ID
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Instruction Manual - Brazed plate heat exchangers
Language
34567071-01 EN
Edition
2014-07
Maintenance
EN
Cleaning liquids
A number of cleaning liquids are listed below and all can be used for both the process and
utility side.
AlfaPhos
An acid cleaning liquid for removing metallic oxides, calcium carbonate, lime and other inorganic
scale. Includes tensides as well as an inhibitor for passivation.
Kalklöser P
An acidic cleaning powder with a corrosion inhibitor effective for removing many types of
inorganic scale. The powder form makes this cleaner very user-friendly. It also has fewer
restrictions on transportation and storage.
AlfaAdd
A neutral cleaning strengthener to be used with AlfaPhos, AlfaCaus and Kalklöser P. Provides
better cleaning results on oily, fatty surfaces and where biological growth occurs. AlfaAdd
also reduces any foaming.
Alpacon Descalant II
An acidic, water-based, non-hazardous cleaning agent designed for the removal of scale,
magnetite, algae, humus, mussels, shellfish, lime and rust.
Alpacon Degreaser II
A neutral degreaser can be used with Alpacon Descalant to reduce possible foaming. Effectively
removes oil, fat or grease layers.
Caution!
The residuals after a cleaning procedure shall be handled according to the local
environmental regulations. After neutralisation, most cleaning solutions may be drained
to the waste water system under the condition that the fouling deposits do not contain
heavy metals, other toxic or environmentally dangerous compounds. It is recommended
that the neutralised chemicals be analysed for any type of hazardous compounds that
were removed from the system prior to disposal.
Document ID
Language
34567071-01 EN
Edition
2014-07
Instruction Manual - Brazed plate heat exchangers
19
Fault tracing
Fault tracing
Pressure drop problems
The pressure drop has increased.
Action
1.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 mm 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.
Correction
YES
NO
Action
2.Compare the pressure drop observed with the one specified for the actual flow rate (see
data printout). Is the pressure drop higher than specified?
Correction
YES
Check the temperature program, see step 3
NO
If the pressure drop corresponds to the specifications, there is no need for action.
If the pressure drop is lower than specified, the pump capacity is probably too
small or the observation may be wrong. See pump instruction manual.
Action
3.Check the thermometer readings. Do the readings correspond to those specified?
Correction
YES
The heat transfer surface is probably clean enough, but the inlet to the heat
exchanger may be clogged by some objects. Check the port area.
NO
Heat transfer is obviously dropping below specifications, because of deposits on
the heat transfer surface, which at the same time also increases the pressure
drop, since the passage becomes narrower.
If a Cleaning-In-Place (CIP) system is available, follow the instructions and use it
to wash out the deposits.
Heat transfer problems
The heat transfer capacity is dropping.
Action
1.Measure temperatures at inlets and outlets. Also measure flow rates on both media, if
possible. 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 °C, and also to use the best equipment available for flow measurement.
Has the heat transfer capacity of the unit dropped below specified values?
Correction
YES
Clean the heat transfer surface. Use the Cleaning-In-Place (CIP) system.
NO
Document ID
20
Instruction Manual - Brazed plate heat exchangers
Language
34567071-01 EN
Edition
2014-07