Armstrong Pumps Sigma Heat Exchanger
Armstrong Pumps Sigma Heat Exchanger
Armstrong Pumps Sigma Heat Exchanger
Instructions
for
SIGMA
Plate Heat
Exchangers
Operating Instructions
Content
1.
General Remarks
2.
3.
Frames
Connections
Plates
Gaskets
Accessories
Installation
3.1
3.2
3.3
4.
4.1
5.
Operation
6.
7.
List of Questions
Leakage
Product Mixture
Heat Transfer Performance Problems
Pressure-loss Problems
8.
Spare Parts
9.
Tools
10.
Documentation
11.
Addresses
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1. General Remarks
API Schmidt-Bretten GmbH & Co. KG is in the business of solving thermal problems since
1879, and is producing the SIGMA series of plate heat exchangers since well over six decades.
We produce a wide assortment of heat exchangers with gaskets for a broad range of heat
exchange applications.
Although our SIGMA heat exchangers are still being utilized in their traditional area of
application, that is the milk and beverage industry, our wide selection of units are employed in
nearly all industrial areas.
The wide scope of possible applications ranges from lubricating oil coolers on ships, to
refrigerant evaporators, to hot water preparators, all the way to fruit products pasteurizing units.
The wide variety of unit sizes, as well as of available plate structures, are the basis for API
Schmidt-Brettens optimum designed plate heat exchangers no matter for which application they
are intended.
In the following text, you will find information concerning the assembly, the functioning, and the
operating of a SIGMA plate heat exchanger.
If you still have questions concerning our products after having read the information, one of our
specialist will be happy to help you.
We wish you much success with the SIGMA plate heat exchangers.
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5 Plate Pack
2 First Plate
10 End Support
8 Movable Cover
Single corrugated heat exchanger plates are combined into a plate packet to form flow
channels, which are enclosed with gaskets.
These flow channels make it possible for the liquids that enter and exit through the connecting
holes consequently to undergo thermal treatment by conducting heat through the heat
exchanger plates.
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2.1 Frames
A variety of frames are available. Their differences consist in construction form, in the type of
material used for their construction, as well as in their strength.
The dimensioning of the standard plate heat exchangers is based on the rules of the German
AD-Merkbltter. The standard selection of materials refer to DIN.
The designation of the frames consists of the following information:
SIGMA 27 N B L
Line of products
Type
Construction Form
Pressure class
N, S, T
A, B, C, D
Construction Material
L
N
V
Lacquered steel
Solid stainless steel
Steel covered with
stainless steel
Construction Forms
N
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2.2 Connections
SIGMA plate heat exchangers come equipped with a range of different connection types
according DIN-Standard.
The choice of corrosion-proof material used for the connections depends on the medium that is
to undergo the thermal process. A higher alloyed and more resistant material is required for the
connections and the lining, if a more aggressive medium is to be treated.
A cost-effective variation would be to employ the same material utilized in the plate gaskets for
the lining of the connections.
Additional connections used for ventilation or draining usually have a smaller nominal width than
the product connections.
The diagram below shows the letters attributed to the position of the connections.
Moving Cover
2.3 Plates
One of the main components of the heat exchanger is the plate package. The number of plates
and the type of plate corrugation used in the heat exchanger unit depends on the type of
thermal process that is to take place.
The flow path through the plate package also depends on the thermodynamic requirements of
the plate heat exchanger.
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All heat exchanger plates are in principle composed of a single plate segments.
Inlet Port
Leakage Section
Distribution Segment
(Triangle)
Collecting Segment
Passing Port
Outlet Port
The composition and the temperature of the media, which are to take part in the thermodynamic
process, determine the type of materiel used for the manufacturing of the heat exchange plates.
As possible materials the following are used in general:
Stainless Steel:
AISI 304, AISI 316, AISI 316L, AISI 316TI, AISI 904L, SMO 254
Nickel Alloys:
Titanium / -alloys:
The thickness of the plate material is depending on the plate type and the required pressure
resistance. It ranges between 0.4 mm and 1.15 mm.
The flow-characteristics of the plate gaps are interlocked with the profile of the plate corrugation.
API Schmidt-Bretten disposes over a wide assortment of plates with varying corrugations. Each
has its own specific hydraulic and thermodynamic properties, as well as in product distribution
and cleaning behavior in relation to the product consistencies.
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Plate packages can consist of plates with varying plate corrugation patterns. The following
corrugation patterns are available for the optimizing of thermodynamic flow paths.
H-Corrugation
W- Corrugation
Y- Corrugation
Z- Corrugation
V- Corrugation
F- Corrugation
Each plate heat exchanger is optimized according to the specific use in mind. Consequently,
various heat exchanger units have different arrangements and flow paths through which the
product is fed.
A parallel or serial arrangement can be achieved by opening or closing the outlet ports.
The plates, which do not have four open inlet / outlet ports, are called turning plates. For a
clear identification of the turning plates, a nomenclature consisting of letters, which are attributed to the various inlet and outlet ports, is used (refer chapter 2.2).
When looking at a heat exchanger plate, with the plate side which holds the gasket facing
towards you, if the inlet and outlet port are situated on the left side then this is a left plate. When
the outlet ports are positioned on the right side this indicates that it is a right plate.
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Turning Plates
AR
BR
CR
DR
BL
AL
CL
DL
ER
FR
GR
HR
FL
EL
HL
GL
IR
JR
KR
LR
JL
IL
LL
KL
MR
NR
OR
PR
NL
PL
OL
ML
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Start Plates
AAR/EAR
ABR/EBR
ACR/ECR
ADR/EDR
ABL/EBL
AAL/EAL
ACL/ECL
ADL/EDL
AER/EER
AFR/EFR
AGR/EGR
AHR/EHR
AFL/EFL
AEL/EEL
AHL/EHL
AGL/EGL
AIR/EIR
AJR/EJR
AKR/EKR
ALR/ELR
AJL/EJL
AIL/EIL
ALL/ELL
AKL/EKL
AMR/EMR
ANR/ENR
AOR/EOR
APR/EPR
ANL/ENL
APL/EPL
AOL/EOL
AML/EML
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2.4 Gaskets
Every heat exchanger plate of a gasketed plate heat exchanger is fitted with a complete gasket.
The gaskets keep the fluids that flow through the heat exchanger separated from each other
and contained within the unit.
Each heat exchanger plate is fitted with two ring- and two field gaskets. The only exceptions are
the plates, which face the frame heads.
Diagonal Gasket
Field Gaskets
Leakage Groove
Ring Gasket
Fastening Clip
Within the gasket is a leakage area with a leakage groove. As soon as diagonal- or ring gasket
is defective this leakage groove makes the leak visible on the outside.
The functioning of these leakage grooves is guaranteed as long as the gasket has not lost its
original shape due to thermal influences, or that the leakage grooves have become congested
due to the impurities contained in the product, or that the plate packet was not tightened
properly below the given final clamping dimension.
In general, there are two ways of fixing the gaskets to the heat exchanger plates:
The fixing of a gasket to a plate by means of adhesives:
A special adhesive is placed as a complete layer into the heat exchanger plates gasket
groove. After the gasket has been fitted in and the adhesive has hardened, the gaskets and
plates are joined permanently.
This method of fixing the gasket to the plate is especially advantageous for systems, which
have to be opened for cleaning on a regular basis.
The gaskets loose their effectiveness with time and then have to be exchanged. When
gaskets are changed, they have to be removed carefully and new ones have to be fixed to
the plates.
Depending on the gasket material and quality, this procedure may be performed directly on
site.
It is however highly recommended that the plates be returned to the manufacturer, who will
then perform the gasket change.
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2.5 Accessories
2.5.1 Intermediate Frames and Intermediate Plates
For a range of applications several sections with varying thermodynamic functions can be
installed within a plate heat exchanger, as is the case within a food stuff pasteurizer with a
cooling, a heating, and a heat recovery section.
Nevertheless, each section requires its own inlet and outlet ports. Intermediate frames which
are built-in to serve as separation between two adjacent sections can be equipped with the
appropriate connections for the functioning of that section.
In contrast, intermediate plates without connections merely serve as separation between two
adjacent sections.
2.5.2 Protection Cover and Insulation
Heat exchangers with operating temperatures of over 50 C or under 10C should be fitted
with a protection cover in order to avoid any injuries through contact.
Direct contact with the heat source can be avoided through the mounting of protection covers.
These protection covers, which are made out of thin stainless steel, are fitted over the plate
pack.
Another safety feature of the protection cover is that it also serves as splash guard against the
mediums contained within the heat exchanger in case of a gasket leak due to aging of the
gasket.
Compared to the large internal heat exchange surface, the exterior of the heat exchangers is
relatively small. Although the exterior surface is not very extensive, for some applications it
would be advantageous to install an isolation barrier.
The plate heat exchange may be insulated using one of two methods. The unit can either be
completely insulated using a solid insulation which encases the whole unit and which can be
removed in one piece, or only the plate pack may be insulated so that any heat losses towards
the outside are avoided. In this case, the plate pack is covered with a protection cover, which
includes a layer of insulation on the inside.
It is the responsibility of the operator to ensure that the proper safety precautions are taken so
that no injuries to persons, or damage to the environment occur in case of heat exchanger
malfunction or damage leading to leakage.
2.5.3 Safety Precautions Against Outer Influences
In general, it is not possible to protect a heat exchanger from outside influences such as heat or
other atmospheric influences.
It is however necessary to foresee certain safety measures. In case of a fire the heat exchanger
unit must be depressurized through a built in automatic control system in order to avoid an
increased risk of damage caused by the pressurized mediums contained within the unit.
As a preventive measure against possible damage from aggressive substances contained in the
surrounding area, all parts of the heat exchange unit, such as the pressure frames, the heat
exchange plates, and the gaskets must be pre-treated accordingly.
When choosing the location of the heat exchanger unit it should be kept in mind that, UV or
other rays can have a negative effect on the gaskets and thus shortening the service life of the
seal.
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3. Installation
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5. Operation
Each plate heat exchanger is designed and built for specific thermodynamic operations with
processing, cleaning, and sterilization cycles taken into account.
Before the heat exchanger unit can be used for the processing of any media other than
originally planed, all parts of the unit which come into contact with the medium, such as gaskets,
heat exchange plates and connections, have to be tested for compatibility with the new medium.
The plate heat exchanger may only be put into operation after it has been verified that the unit is
capable of processing the new medium.
It is the responsibility of the units owner to ascertain that upon feeding a new product into the
unit no chemical or thermal reactions will occur due to reaction with previously treated fluids
which remained in the unit.
If the possibility of such a reaction exists then the heat exchange unit must be completely
drained before a new fluid is pumped in.
If during a thermal process the operating temperature, operating pressure or the flow rate of the
product feed has to be changed, the adjustment should be done slowly and over longer span of
time.
In general, a continuing operation cycle is best suited for a heat exchange unit.
If however the continuing operation of the heat exchange unit is not possible due the required
thermal treatment conditions, precautions have to be foreseen in order to avoid rough switch
over to a different thermal process function.
Often occurring pressure variations even in small amplitudes may have a negative effect on the
service life of the gaskets.
If possible it should be avoided that a plate heat exchanger constantly undergoes extreme temperature variations, from being hot to completely cold, since this process speeds up the aging of
the gaskets.
To minimize the stress and to extend the service life on the gaskets additional spring joint
packages can be built into the tie rods.
Not only, the variations in operation conditions can damage the heat exchanger unit, but
processes, which take place within other parts of the system. On- or off-switching of other
components may cause pressure shocks that are carried all the way through the system to the
heat exchanger unit.
In this case, the demands for the heat exchanger units rigidity should be compared with the
actual parameters given for the original function of the unit.
With a plate heat exchanger the risk exists that a plate cracks occurs. This problem may be
caused through the deposit of corrosive materials on the heat exchanger plates or due to
pressure variations that occur over longer operation periods.
In case of a plate crack the mixing of the products may occur.
If one of the products must be kept clean, and may not be contaminated by the other medium
taking part in the thermodynamic process, possible contamination in case of a plate crack can
be avoided by pumping this medium through the unit at a much higher pressure than the other
fluid.
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Concentration
[wg.-%]
Gasket
Material
up to 5
no limit
up to 90
NBR
EPDM
up to 5
up to 70
NBR
EPDM
up to 5
up to 90
NBR
EPDM
up to 2
0,5
up to 50
NBR
EPDM
up to 4
up to 40
NBR
EPDM
up to 1
up to 2
20
NBR
EPDM
no limit
120
NBR
EPDM
Hot water
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Take care not to tilt the cover to one side or bend it at any stage (max. inclination 10 mm).
The plate heat exchanger should not be tightened more than necessary so that the service life
of the gaskets is not reduced due to excessive pressure.
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Problem
Solution
Possible causes
Corrosion
of the plates
Replacement
of the plates
Chlorides
Deformation
of the plates
Replacement
of the plates
Pressure shocks
Over-pressing
of the plates
Plate cracks
Replacement
of the plates
Pressure changes,
Chemical attacks on
the plate material
Aging
of the gaskets
Replacement
of the gaskets
End of lifetime,
Temperature- or
pressure-changes
Change the
gasket material
Leakage
when cold
Replacement
of the gaskets
Installation of
spring packages
on the tie rods
Hardening
of the gaskets
Replacement
of the gaskets
Inadequate chemical
resistance,
Temperatures
too high
Change the
gasket material
Swelling
of the gaskets
Replacement
of the gaskets
Inadequate chemical
resistance,
Temperatures
too high
Change the
gasket material
Gasket cracks
Replacement
of the gaskets
Mechanical stress
Arrangements to avoid
mechanical stress
Problem
Solution
Possible cause
Corrosion
of the plates
Exchange
of the plates
Chlorides
Plate cracks
Exchange
of the plates
Pressure changes,
Chemical attacks on
the plate material
Braking of the
connections
Exchange
of the connections
Stresses in the
pipeline
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Problem
Solution
Possible cause
Fouling
in the plate gaps
Cleaning
of the plate heat
exchanger
Particles, Fibers,
Bacteria
Composition
of the product
Hard deposit due to
high temperature
Fouling
in the connections
Changing
of the
operating conditions
Cleaning
of the plate heat
exchanger
Particles, Fibers,
Bacteria
Switch back
to old operating
conditions,
if possible
Entrance
temperatures
Composition
of the product
Changing of the
plate arrangement
or plate type
Composition
of the product
Problem
Solution
Possible cause
Fouling
in the plate gaps
Cleaning of the
PHE
Particles, Fibers,
Bacteria
Consistency
of the product
Hard deposit due to
high temperature
Fouling
in the connections
Cleaning of the
PHE
Particles, Fibers,
Bacteria
Composition
of the product
Changes of
operating conditions
Entrance
temperatures
Flow rates
Changing of the
plate arrangement
or plate type
Composition
of the product
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8. Spare Parts
It is recommended to keep spare parts in stock at the production site, as far as the plate heat
exchanger is a necessary and urgent component of your production process.
Depending on the possible off-time the following variants of spare parts vary:
Spare gaskets
Single spare plates
Complete gasketed plate package
A complete stand-by PHE
Normally it is no necessary to keep spare parts for the frames or intermediate frames in stock at
the facility.
Keep the following conditions for the storage of the above mentioned spare parts:
Gaskets and gasketed plates should not be stored for more than two years
Dont store the parts outside
Storage is good at temperatures below room temperature
If possible store the parts in a dark room and avoid neon light
The atmosphere in the store has to be free of solvents or ozone
9. Tools
For best handling for mounting or maintenance work with the plate heat exchanger, several
tools should be available.
Spanner for smaller units
Wretch-spanner for larger units
Electric or hydraulic screwing machine for very large units
Lifting gears as fork lifter or a crane should be on site, if frame parts have to be changed
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10. Documentation
The standard documentation contains the following papers and pieces:
Name Plate
Dimensioned drawing of the unit
Parts List
Plate Diagram
Technical Datasheet
Operating Manual
Optional the documentation can be supplemented by:
Manufacturer Certificate
Declaration of conformity (where appropriate)
Material certificate
Approval drawings
Documentation of inspection by an inspection company (for example TV, GL)
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11. Addresses
Feel free to contact our stuff in the main facility in Bretten or in one of the subsidiaries outside
Germany, if you have any question or need any information about spare parts or other products
of API Schmidt-Bretten.
API Schmidt-Bretten GmbH & Co. KG
Langenmorgen 4
75015 Bretten
Germany
Phone +49 / 7252 / 53 - 0
Fax
+49 / 7272 / 53 200
Email info@apischmidt-bretten.de
Web www.apischmidt-bretten.de
Direct contact to our aftersales services:
Tel.: +49 (7252) 53-149
Fax: +49 (7252) 53-200
Email: service@apischmidt-bretten.de
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