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Plate Heat ExchangerOperational and Maintenance Manual

Alfa Laval5400 International Trade DriveRichmond, VA 23231(804) 222-5300 FAX (804) 236-3276

Model Type

Mfg. No(s).

REV. 0401

CASE16

Text Box

Mahan's Thermal Products, Inc. 30 Juniper Court Covington, GA 30016 (770)786-5555 Fax (770)786-3020

TO AVOID HAND INJURIES, PROTECTIVE GLOVESSHOULD ALWAYS BE WORNWHEN HANDLING PLATES.

NOTICE

PROTECTIVE SHROUDS

IT IS THE RESPONSIBILITY OF EACH PERSON OPERATING ORREPAIRING EQUIPMENT TO TAKE THE NECESSARYPRECAUTIONS TO COMPLY WITH ALL APPLICABLE SAFETYREGULATIONS.

ALFA LAVAL PROVIDES PROTECTIVE SHROUDS FOR ALLOUR PLATE HEAT EXCHANGERS. THESE SHROUDS WILL PRE-VENTPOSSIBLE INJURIES AND/OR DAMAGE AS A RESULT OF SUDDENLEAKAGE FROM THE PLATE PACKAGE.

List of contents

TO OUR VALUED CUSTOMER 1

• Alfa Laval Locations 1.1

THE NAME PLATE - AND THE 2

IDENTIFICATION OF THE EQUIPMENT

• Code Plate & Identification Number Locations 2.1, 2.2

GENERAL 3

• Storage 3.1, 3.2

• Lifting 3.2

• Foundation 3.3

• Installation 3.3, 3.4

• Special Loose Flange Connections 3.5

THE MAIN COMPONENTS AND THEIR FUNCTIONS 4A

FOR PARALLEL FLOW UNITS

• List of Parallel Flow Units 4A.1

• Function 4A.2

• How It Works 4A.3

• Heat Transfer 4A.4

• Pressure Drop 4A.4

• Plates 4A.5

• Gaskets 4A.6, 4A.7

THE MAIN COMPONENTS AND THEIR FUNCTIONS 4B

FOR DIAGONAL FLOW UNITS

• List of Diagonal Flow Units 4B.1

• Function 4B.2

• How It Works 4B.3

• Heat Transfer 4B.4

• Pressure Drop 4B.4

• Plates 4B.5, 4B.6

• Gaskets 4B7, 4B.8, 4B.9, 4B.10

CHAPTER

List of contents

OPERATION 5

• Starting Up 5.1, 5.2

• Unit in Operation 5.3

• Shut Down 5.3

• The Risks of Not Complying With 5.4

The Start-Up and Shut-Down Procedures

OPENING AND CLOSING OF THE PLATE PACKAGE 6

• Opening 6.1, 6.2, 6.3, 6.4, 6.5

• Removal and Insertion of plates 6.6

• Closing 6.7, 6.8, 6.9, 6.10, 6.11

MAINTENANCE 7

• Cleaning 7.1, 7.2, 7.3, 7.4, 7.5

• Regasketing 7.6, 7.7, 7.8, 7.9

• End Plate II Gaskets For Parallel Flow Units 7.10

• End Plate II Gaskets For Diagonal Flow Units 7.11

FAULT DETECTION 8

• Leakage at Connections or Plates 8.1, 8.2

• Internal Mixing of Media 8.3

• Pressure Drop Problems 8.4

• Heat Transfer Problems 8.5

SUPPLEMENTARY PARTS 9

• Partition Plate 9.1

• Instrument Ring 9.2

CHAPTER

To our valued customer:

Thank you for purchasing an Alfa Laval Plate Heat Exchanger. As the world's largest manufac-turer of Heat Exchangers, we are very proud of our products and services. We value youas our customer and wish to assure your satisfaction. We have prepared this Instruction Manual toassist you with your Alfa Laval Plate Heat Exchanger in various situations. We suggest thatyou look through it carefully, and, above all, make it readily available to any personnel whomay need it for reference.

We would appreciate any comments you have about our products and/or services. Please con-tact our local Representative who is listed in your local telephone directory or any of the Alfa Lavallocations listed below. We do stand behind our products and services, and wish to thank youagain for your confidence in Alfa Laval.

1.1

1

Alfa Laval101 Milner AvenueScarborough, Ontario M1S 4S6Canada(416) 299-6101FAX (416) 297-8690

Alfa LavalHeat Transfer Center5400 International Trade DriveRichmond, VA 23231(804) 222-5300FAX (804) 236-3276

2 The name plate - and the identification of the equipment

Model type and manufacturing numbers(s)

A name plate like the one shown below is fixed to the apparatus as shown above andit gives the following information

2.1

2

2.2

2The name plate - and theidentification of the equipment

WHENEVER USING THE MANUAL, CHECK FIRST THAT THESERIAL NUMBER ON THE FRONT COVER IS IDEN-TICAL TO THAT ON THE NAME PLATE OF THE EQUIPMENT.

IN ALL CORRESPONDENCE WITH ALFA LAVAL, PLEASE REFER TO THE MANUFACTURING SERIAL NUMBER, FORTRUE IDENTIFICATION OF THE EQUIPMENT.

WHENEVER CONTACTING ALFA LAVAL ABOUT A PART FORYOUR PLATE HEAT EXCHANGER, BE SURE TO STATE THEMANUFACTURING SERIAL NO(S), AND MODEL TYPE.

This instruction manual has been issued for many differentmodels of Alfa Laval industrial PHEs. There are separatemanuals for industrial, sanitary, spiral, alfa rex, brazed & evaporator/condensor heat exchanges.

•

•

•

2.2

Genera l3

3.1

STORAGE

In this section, names of heat exchanger parts are mentioned forthe first time. For your information, see Chapters 4A or 4BFUNCTION.

1. Unless otherwise agreed, ALFA LAVAL delivers the plate heat exchanger ready to be put in service upon arrival. This means that theplate package is tightened to its correct measurement A.

Should it be necessary, however, to store the equipment for alonger period (1 month or more) before, certain precautions shouldbe made in order to prevent unnecessary wear of the equipment:

Preferably, the heat exchanger should bestored inside, in a room with a temperaturearound 15 to 20 degrees Celsius (60 to 70degrees Fahrenheit) and humidity around 70%

2.

There should ABSOLUTELY NOT be anyOZONE-PRODUCING equipment in the room,like electric motors or arc-welding equipment,since ozone destroys many rubber materials(cracking).

Do not store organic solvents or acids in theroom.

Avoid heat or ultraviolet radiation.

Wrapping the PHE with a non-transparent plas-tic film is a good precaution. Use of transparentfilm can alter paint color if unit is stored in directsunlight.

3.

A

3

STORAGE

General

The tightening bolts should be well coveredwith good rust preventing coating, suitabletypes (LUBRIPLATE FGL-2 or Equivalent) andif not connected to the pipe system, the con-nections should be covered.

If the heat exchanger must be stored outdoors,the precautions mentioned above should betaken as far as practical. The need for protec-tion against the climate etc. is of course evenmore important in this case.

If for any reason the heat exchanger isremoved from service for a long period, it isadvantageous to follow the advice above, evenif the equipment is not moved from the location.

The heat exchanger should be VENTED ANDDRAINED, and depending on the media pro-cessed, it is recommended to RINSE ANDDRY it, before it is stored.

Whenever the heat exchanger is lifted, strapsshould be placed around tightening bolts onboth sides of the unit, as shown in picture. If lift-ing lugs or lifting eyes are provided, always usechains or lifting cables rated above the pub-lished weight of the heat exchanger.

4.

5.

1.

LIFTING

NEVER LIFT BY THE CONNECTIONS OR THE STUDS AROUND THEM!

3.2

Genera l

3.2

LIFTING CONTINUED

If Lifting Lugs are provided

If you are to lift the heat exchanger itself, strapsshould be used. They should be placed asshown on the picture.

On smaller units (4” connected size smaller)typically two lifting lugs are required instead offour.

WARNING!Never lift by the connections or the studsaround them.

3 GeneralFOUNDATIONS.

All information necessary for the preparation of the foundationappears on the data sheet provided by ALFA LAVAL.

In some cases (installation on board a ship,when processing corrosive liquids, etc.) it maybe practical to place the heat exchanger in aDRAINAGE BOX (with capacity for the totalvolume of the heat exchanger). The outlet ofthe drainage box should be generously dimen-sioned, not less than (2”) 50 mm diameter.

INSTALLATION.

BEFORE connecting any piping to the heat exchanger, MAKE SURE THAT ALLFOREIGN OBJECTS HAVE BEEN FLUSHED OUT OF THE SYSTEM!

PLEASE OBSERVE THATThe measurements given in the picture aboveare recommended by ALFA LAVAL, it is nec-essary to leave free space around the equip-ment, to provide access and make future serv-ice possible. Except for a place to put theplates, if removed from the heat exchanger,NO FURTHER SPACE is required for servic-ing the PHE.

PLEASE OBSERVE THATThe measurements given in the picture arerecommended by ALFA LAVAL, to provide rea-sonably good working conditions during instal-lation of the heat exchanger as well as forfuture maintenance and service. If floor spaceis restricted, the dimensions suggested can bereduced. It is left to the purchaser to decidejust how much access space is required.

Recommended free space foropening and closing.

This field should be kept freefrom fixed installations.

3.3

4” (100mm)

2” (50mm)

Wx1.5 Wx1.5 Wx1.5

3General

PIPES

Always ensure that no measurable stress isplaced on the heat exchanger by the pipingsystem.

SHUT OFF VALVES

To enable the heat exchanger to be openedwhen necessary shut off valves should be pro-vided on all connections.

PRESSURE RELIEF DEVICES

It is the responsibility of the user to ensure thatthe required pressure relief devices are proper-ly installed prior to initial operation. Refer to theapplicable Code(s) and correspondingStandard(s) for proper size requirements ofthese pressure relief devices.

CONNECTIONS ON THE PRESSURE PLATE(REAR COVER)

Some plate heat exchangers may also haveconnections on the pressure plate. In suchcases, it is important to check against thedrawing or the name plate that the plate packhas been tightened to the right measurementbefore the piping is connected.

Whenever piping is connected to the pressureplate, a short 90o spool piece shall be installedbetween the heat exchanger and the piping.These should be directed upwards or side-ways. This simplifies pressure plate removalduring servicing.

Venting of both sides of the heat exchangermust be provided. This is important andenables air to be drawn from the system duringstart-up. It also enables air or gas to beremoved during operation, and it enables fasterdrainage.

3.4

3General

Loose Flanges are provided on certain modeltypes due to interference. When provided theseflanges shall be incorporated into the piping.

MODELS WITH BOTH "S" AND "T" PORTCONNECTIONS

M6-FD, M6-MFD, M6-MWFD, M10-BFD, M10-MFD, M10-BWFD, M10-BDFD, M20-MFD*,M20-MWFD*

MODEL TYPES WITH LOOSE FLANGE ON T PORT CONNECTIONS ONLY:

M6-FG, M6-MFG, M6-MWFG, M10-BFG, M10-MFG, M10-BWFG, M10-BDFG, V28-FD*, V45-FD*, M20-MFG, M20-MWFG

* Loose flange only when design pressuresabove 230 psi.

Notes: 1) Sports connections on these model typesutilized industry standard flanges.2) Not all exchangers require T port connections.

PIPING CONNECTION

The loose flange is connected to piping by useof a commercially available stub end of samematerial as the piping.

The stub end is installed as shown and then buttweld to the piping.

3.5

Special Loose Flange Connections

"M" SERIES UNITS:

M3-VG

M6-FG; M6-FD; M6-MFG; M6-MFD; M6-MWFD/FG/FDR/FGR

M10-BFM; M10-BFG; M10-BFD; M10-MFG; M10-MFD;

M10-BWFG; M10-BWFD; M10-BWFGR, M10-BWFDR

M15-BFG; M15-BFD; M15-BFS; M15-MFG;

M15-MFD; M15-MFS; MK15-BWFD; MK15-BWFG

M20-MFG; M20-MFM; M20-MFD; M20-MWFG; M20-MWFD

M30-FM; M30-FG; M30-FD

MA30-FD; MA30-FG; MA30-WFG; MA30-WFD

MX25-BFG; MX25-BFD; MX25-BFS

EC500-WTFE; EC500-WTFL

"V" SERIES UNITS:

V8-VG, V13-FG, V13-FD, V20-FG, V20-FD

4A LIST OF PARALLEL FLOW UNITS

4A.1

"A" SERIES UNITS:

AM10-FG; AM10-FS

A15-BFL; A15-BFG; A15-BFD; A15-BWFG; A15-BWFD

A20-BFL; A20-BFG; A20-BFD

AM20-FG; AM20-BFG; AM20-WFG; AM20-SFG; AM20-DWFG

AK20-FG; AK20-FD; T200-FG; T200-FD

AX30-BFG; AX30-BFD; AX30-BWFG; AX30-BWFD

A35-HA

4APARALLEL FLOW UNITS

FunctionTHE MAIN COMPONENTS OF THE PLATE HEAT EXCHANGER AND THEIR FUNCTIONS.

In ALFA LAVAL Plate Heat Exchangers, heat is transferred from one medium to another throughthin metal plates which have been pressed into a special pattern.

3. CONNECTIONSHoles matching the piping leadthrough the frame plate, permittingthe media to enter into the heatexchanger. Threaded studs aroundthe holes secure the pipes to theequipment. Depending on the appli-cation, metallic or rubber-type LIN-INGS may protect the edges of theholes against corrosion.

6. TIGHTENING BOLTSWith the package of thin plateshanging between the frame plateand the pressure plate, a number ofTIGHTENING BOLTS are used topress the thin plates together, bring-ing them into metallic contact, and tocompress the gaskets, enough toseal off the narrowpassages which have now been formed between the plates.

8. CHANNEL PLATES

9. GASKETThese plates are called CHANNELPLATES. A groove along the rim ofthe plate and around the ports hold aGASKET, usually made of a rubber-type material.

Heat is transferred through the sur-face which is contained by the gas-ket, except for some small areasnear the corners.

The number of plates in your heat exchanger is determined by the sizeof the heat transfer surface required.

1. FRAME PLATE

2. SUPPORT COLUMNThe two bars are suspended be-tweenthe FRAME PLATE, to which in mostcases the piping is connected, and aSUPPORT COLUMN.

4. CARRYING BAR

5. GUIDING BARThe plates hang from a CARRYINGBAR at the top and are kept in line bya GUIDING BAR at the bottom.

7. PRESSURE PLATEThe pressure plate is hung on thecarrying bar and is moveable, as arethe heat transfer plates. In somecases piping may be connected tothe pressure plate.

4A.2

1.2. 3.

4.

5.

6.

7. 8.

9.

4A PARALLEL FLOW UNITS

How it works

When a package of plates are pressed together,the holes at the corners form continuous tunnelsor manifolds, leading the media (which partici-pate in the heat transfer process) from the inletsinto the plate pack, where they are distributed inthe narrow passages between the plates.

Because of the gasket arrangement on theplates, and the placing of “A” and “B” platesalternately, the two liquids enter alternate pas-sages, e.g. the warm liquid between even num-ber passages, and cold liquid between oddnumber passages.

Thus the media are separated by a thin metalwall. In most cases the liquids flow in oppositedirections.

During the passage through the equipment, thewarmer medium will give some of its heat ener-gy to the thin wall, which instantly looses it againto the colder medium on the other side.

The warmer medium drops in temperature,while the colder one is heated up.

Finally, the media are led into similar hole-tun-nels at the other end of the plates and dis-charged from the heat exchanger.

4A.3

AB

B

B

A

A

A

S1

B

S2S31

S4

2

3

4

5

A

B

PARALLEL FLOW UNITS 4AHeat transfer

The purpose of the equipment is to transfer heatfrom one medium to another. Heat passes veryeasily through the thin wall separating the twomedia.

The novel pattern into which the plate materialhas been formed not only gives strength and rigid-ity, but greatly increases the rate of heat transferfrom the warmer medium to the metal wall andfrom the wall to the other medium.

This high heat flow through the walls can be seri-ously reduced by the formation of deposits of var-ious kinds on the wall surfaces.

The pattern of corrugation on Alfa Laval platesmentioned above induces highly turbulent flow.The turbulence gives strong resistance to the for-mation of deposits on the plate surface; however,it cannot always eliminate fouling.

The deposits may increase the total “wall thick-ness” substantially, and they consist of materialsthat have a much lower thermal conductivity thanthe metal plate. Consequently a layer of depositscan severely reduce the overall heat transfer rate.

The deposits will be considered in the chapter onMAINTENANCE and CLEANING. At this pointwe will only establish that this fouling is unwantedand can under certain circumstances, be harmfulto the heat exchanger because corrosion mayoccur under the deposits.

Pressure dropPressure drops are wasted energy.

All pipe systems and equipment included inthem offer resistance to media flowing throughthem.

Some pressure drop is unavoidable, but for agiven PHE it should be kept as close as possi-ble to the designed value.

The formation of deposits on the heat transfersurfaces instantly leads to a reduction of thefree space between the plates. This meansthat more energy is needed to get the desiredflow through the equipment.

It is clear that the fouling of the surfaces is unde-sirable.

Larger particles and fibers may also be drawninto the heat exchanger and clog the passageways if strainers or other means of protectionhave not been provided for.

A reduced ability by the heat exchanger to holdthe desired temperatures, in combination withan increased pressure drop on any of themedia, indicates that fouling or clogging is tak-ing place.

For corrective action, see MAINTENANCE andCLEANING.

4A.4

PARALLEL FLOW UNITS 4A

4A.6

Studying the pictures, you will observe that on a plate hangingvertically, the gasket rests in a groove which includes the heattransfer area

and two corners on theleft side.

OR two corners on theright side.

Smaller rings surround thetwo remaining corners.

We decide that we will name the plates after these two situations.

An A-plate is aplate hanging withthe chevron pointingdownwards.

A B-plate is aplate hanging withthe chevron pointingupwards.

If we turn an A-plate upside down we will have a B-plate:

A B

PARALLEL FLOW UNITS

4A.7

4AGaskets

The GASKET is molded in one piece. The material is normally anelastomer, selected to suit the actual combination of temperature,chemical environment and possible other conditions that may bepresent.

The one-piece gasket consists of:1. One field gasket2. Two ring gaskets3. Links

The field gasket is by far the larger part contain-ing the whole heat transfer area and the two cor-ners connected to it. The ring gaskets seal off theremaining two corners.

These three pieces are held together by a fewshort links, which have no sealing function at all.Their purpose is simply to tie the pieces togetherand to add some support in certain areas. Onsome plate heat exchangers, the gasket is held inplace on the plate by means of a suitable cementor glue.

2

2

1

3

3


4A.8

Gaskets

As already demonstrated, the two media areeffectively kept apart by the ring and field gas-kets. To prevent intermixing of the media in thecorner areas where field and ring gaskets arevery close to each other, the link pieces have anumber of slots which opens the area betweenthe field and ring gaskets to atmosphere. Anyleakage of media across either gasket willescape from the heat exchanger through theslots.

It is important that these openings are keptclear. If they are not, there is a risk that should aleak occur in that region of the plate, there mightbe a local pressure build-up, which could allowone medium to mix with the other.

Care should be taken not to cut or scratch thegaskets while handling plates.

PARALLEL FLOW UNITS4A

4A.9

TRANSITION PLATEM30, MX25, A20-B, AM20, AK20, T200, A15-B, M15, M10, M6

Ring Gaskets

Collars (Metal)

Channel Plate Gaskets

Pressure Plate

“A” SERIES UNITS:A10-BFG; A10-BFDAX35-FGA45-FG

"P" SERIES UNITS:P2-FG; P2-VLCH; P2-DWFGP3-E;P3-EH

"M" SERIES UNITS:M3-XVG

"V" SERIES UNITS:V28-FG, V28-FD, V45-FG, V45-FD, V110-FG, V110-FD,V170-FG, V170-FD, V280-FG, V280-FD

4B List of Diagonal Flow Units

4B.1

4BDIAGONAL FLOW UNITS

4B.2

THE MAIN COMPONENTS OF THE PLATE HEAT EXCHANGER AND THEIR FUNCTIONS.

In ALFA LAVAL Plate Heat Exchangers, heat is transferred from one medium to another through thinmetal plates which have been pressed into a special pattern.

3. CONNECTIONSHoles matching the piping leadthrough the frame plate, permittingthe media to enter into the heatexchanger. Threaded studs aroundthe holes secure the pipes to theequipment. Depending on the appli-cation, metallic or rubber-type LIN-INGS may protect the edges of theholes against corrosion.

6. TIGHTENING BOLTSWith the package of thin plates hang-ing between the frame plate and thepressure plate, a number of TIGHT-ENING BOLTS are used to press thethin plates together bringing them intometallic contact, and to compress thegaskets enough to seal off the narrowpassages which have now beenformed between the plates.

8. CHANNEL PLATES

9. GASKETThese plates are called CHANNELPLATES. A groove along the rim ofthe plate and around the ports hold aGASKET, usually made of a rubber-type material.

Heat is transferred through the sur-face which is contained by the gas-ket, except for some small areas nearthe corners.

The number of plates in your heatexchanger is determined by the sizeof the heat transfer surface required.

1. FRAME PLATE

2. SUPPORT COLUMNThe two bars are suspended be-tweenthe FRAME PLATE, to which in mostcases the piping is connected, and aSUPPORT COLUMN.

4. CARRYING BAR

5. GUIDING BARThe plates hang from a CARRYINGBAR at the top and are kept in line bya GUIDING BAR at the bottom.

7. PRESSURE PLATEThe pressure plate is hung on thecarrying bar and is moveable, as arethe heat transfer plates. In some cas-es piping may be connected to thepressure plate.

1.2. 3.

4.

5.

6.

7. 8.

9.

Function

4B DIAGONAL FLOW UNITS

How it works

When a package of plates are pressed together,the holes at the corners form continuous tunnelsor manifolds, leading the media (which partici-pate in the heat transfer process) from the inletsinto the plate pack, where they are distributed inthe narrow passages between the plates.

Because of the gasket arrangement on theplates, and the placing of “A” and “B” platesalternately, the two liquids enter alternate pas-sages, e.g. the warm liquid between even num-ber passages, and cold liquid between oddnumber passages.

Thus the media are separated by a thin metalwall. In most cases the liquids flow in oppositedirections.

During the passage through the PHE, thewarmer medium will give some of its heat ener-gy to the thin wall, which instantly looses it againto the colder medium on the other side.

The warmer medium drops in temperature,while the colder one is heated up.

Finally, the media are led into similar hole-tun-nels at the other end of the plates and dis-charged from the heat exchanger.

4B.3

B

B

B

A

A1

2

3

4

5A

S1

B

S2S3

S4

B

A

A

DIAGONAL FLOW UNITS 4BHeat transfer

The purpose of the equipment is to transfer heatfrom one medium to another, and heat passesvery easily through the thin wall separating thetwo media.

The novel pattern into which the plate materialhas been formed not only gives strength and rigid-ity, but greatly increases the rate of heat transferfrom the warmer medium to the metal wall andfrom the wall to the other medium.

This high heat flow through the walls can be seri-ously reduced by the formation of deposits of var-ious kinds on the wall surfaces.

The pattern of corrugation on Alfa Laval platesmentioned above induces highly turbulent flow.The turbulence gives strong resistance to the for-mation of deposits on the plate surface; however,it cannot always eliminate fouling.

The deposits may increase the total “wall thick-ness” substantially, and they consist of materialsthat have a much lower thermal conductivity thanthe metal plate. Consequently a layer of depositscan severely reduce the overall heat transfer rate.

The deposits will be considered in the chapter onMAINTENANCE and CLEANING. At this pointwe will only establish that this fouling is unwantedand can under certain circumstances, be harmfulto the heat exchanger because corrosion mayoccur under the deposits.

Pressure drop

Pressure drops are wasted energy.

All pipe systems and equipment included inthem offer resistance to media flowing throughthem.

Some pressure drop is unavoidable, but for agiven PHE it should be kept as close as possi-ble to the designed value.

The formation of deposits on the heat transfersurfaces instantly leads to a reduction of thefree space between the plates. This meansthat more energy is needed to get the desiredflow through the equipment.

It is clear that the fouling of the surfaces isundesirable.

Larger particles and fibers may also be drawninto the heat exchanger and clog the passageways if strainers or other means of protectionhave not been provided for.

A reduced ability by the heat exchanger to holdthe desired temperatures, in combination withan increased pressure drop on any of themedia, indicates that fouling or clogging is tak-ing place.

For corrective action, see MAINTENANCE andCLEANING.

4B.4

4B DIAGONAL FLOW UNITSPlates

4B.5

Studying the pictures, you will observe that on a plate hangingvertically, the gasket rests in a groove which includes the heattransfer area

rings surroundthe remaining corners

and two corners (theupper left-hand cornerand the lower right-hand corner.

OR two corners (the upperright-hand corner andthe lower left-handcorner.

rings surround thetwo remaining corners

Depending on which two corners are included with the heattransfer area, the plate is called an A- or a B-Plate.

An A-plate is aplate hanging with the chevron pointingdownwards.

A B-plate is aplate hanging withthe chevron pointingupwards.A B

DIAGONAL FLOW UNITS 4BPlates

We can make a B-Plate from an A-plate or the opposite,by changing the gasket and turning the plate upside down.

4B.6

A

B

1. 2. 3.

4. 5.

DIAGONAL FLOW UNITS

4B.7

4BGaskets

The GASKET is molded in one piece. The material is normally anelastomer, selected to suit the actual combination of temperature,chemical environment and possible other conditions that may bepresent.

The one-piece gasket consists of:1. One field gasket2. Two ring gaskets3. Links

The field gasket is by far the larger part contain-ing the whole heat transfer area and the two cor-ners connected to it. The ring gaskets seal off theremaining two corners.

These three pieces are held together by a fewshort links, which have no sealing function at all.Their purpose is simply to tie the pieces togetherand to add some support in certain areas. Onsome plate heat exchangers, the gasket is held inplace on the plate by means of a suitable cementor glue.

2

2

1

3

3

DIAGONAL FLOW UNITS 4B

As already demonstrated, the two media areeffectively kept apart by the ring and field gas-kets. To prevent intermixing of the media in thecorner areas where field and ring gaskets arevery close to each other, the link pieces have anumber of slots which open the area betweenthe field and ring gaskets to atmosphere. Anyleakage of media across either gasket willescape from the heat exchanger through theseslots.

It is important that these openings are keptclear. If they are not, there is a risk that shoulda leak occur in that region of the plate, theremight be a local pressure build-up, which couldallow one medium to mix with the other.

Care should be taken not to cut or scratch thegaskets while handling plates.

Gaskets

4B.8

PARALLEL FLOW UNITS4ATRANSITION PLATEM30, MX25, A20-B, AM20, AK20, T200, A15-B, M15, M10, M6

4A.9

Ring gaskets

Collars (Metal)

Pressure plate

Channel plate gaskets

NON MACHINED PRESSURE PLATE

Sheet Lining

Pressed Collar

Ring Gasket

End Plate

Transition Plate

Rubber Gasket

Sheet Lining, samematerial in metal ring

Metal Ring


4A.10

MACHINED PRESSURE PLATE (AX30, AM20 AND OBSOLETE FRAMES)

Weld

5 Operation

BEFORE STARTING UP FOR THE FIRSTTIME OR AFTER A LONG TIME IN STOR-AGE: MAKE SURE THAT THE PLATEPACK IS COMPRESSED TO THE COR-RECT MEASUREMENT A! Check with theDrawing or Nameplate, which is providedwith each heat exchanger.

It is very important that the system to whichthe heat exchanger is connected, is pro-tected against sudden and extreme varia-tions of temperature and pressure. This isnot only for the heat exchanger but also forthe pipe system itself and every piece ofequipment included in it.

This should be kept in mind whenever amaneuver is to be carried out, includingstarting up of the pumps in the system.

Before starting any pump, check whetherinstructions exist, telling you which pumpshould be started first.

Check that the valve between the pumpand the equipment, controlling the flow rate ofthe system which you are about to start upis closed.

Check that the valve at the exit, if there isone, is fully open.

START UP

1.

2.

3.

4.

5.1

1.

2.

3.

4.

5.2

Operation 55. Open the vent.

6. Start the Pump.

7. Open the valve slowly.

8. When all air is out, close the vent.

9. Repeat the procedure for the other media.

5.

6.

7.

8.

5 Operation

5.3

UNIT IN OPERATION

Any adjustment of the flowrates required tomaintain correct temperatures or pressuredrops should be made slowly, in order to pre-vent shocks to the system.

Problems in keeping up the performance ofthe heat exchanger may be caused by achange

SHUT-DOWN

If the heat exchanger is going to be shut down - or if for any reasonthe pumps are to be stopped - the following procedure should befollowed:

in some of the temperature conditions, theheat load or by fouling.

As long as the PHE is operating to satisfaction,it should be left without any interference.

1. First establish whether instructions exist that specify which side should be stopped first.

2. SLOWLY CLOSE THE VALVE controlling the flowrate of the pump you are about to stop.

3. When the valve is closed, stop the pump.

4. Repeat the procedure for the other side.

5. Poor quality cooling water may be hazardous to metallic materials. Typical examples are corrosion of stainless steels and nickel alloys.

If for any reason the heat exchangeris shut down for a longer period (more than a number of days), it should be drained, and depending onthe media processed, it is recommendable to rinse and dry it.

1.

2.

3.

5.4

Operation 5

THE RISKS OF NOT COMPLYING WITH THE START-UPAND SHUT-DOWN PROCEDURES.

Valves must be operated gradually. The longerthe pipes and the higher the flowrate, the moreimportant this becomes.

WATER HAMMER is the name given to a shortduration pressure peak, traveling along the pipeas a wave at the speed of sound, and resultingfrom a sudden deceleration of the motion of thefluid in a closed system.

Thus, it is usually related to the shutting down ofa system. However, when starting up a systemwith open valves and empty pipes, the fluid mayburst into some obstacle, like a fine mesh strain-er, a flow meter or a heat exchanger, causing asudden reduction of the flow velocity - if not acomplete halt, and so we may have the conditionsof a Water Hammer.

In the worst case, the pressure surge caused bysuch a sudden stop of the motion of a fluid, canbe several times the normal pressure of thesystem.

Therefore it is very important for the protectionof the whole installation that start-ups and close-downs are carried out with great care.

A liquid in motion in a pipe system represents alot of energy, and it must be very carefully dealtwith.

Particularly when the fluid is stopped it is imper-ative that this is done smoothly.

NOTE!For this reason fast-closing valves should not beused unless the pipes of the system are veryshort.

6 Opening

Slowly close the valves on the in-lets. Shut off the inlet side, closingthe highest pressure first.

Switch off pumps.

Close the valves on both outlets.

If the heat exchanger is hot, waituntil it has cooled down to about40oC (100oF).

Drain

Dismantle any pipe bends connect-ed to the pressure plate, so that itcan be moved freely along the car-rying bar.

6.1

1.

2.

3.

4.

5.

6.

1. 4.

5.2.

3. 6.

(100oF)

6Opening

Inspect the sliding surfaces of thecarrying bar and wipe clean

Inspect pressure plate roller.

Pull back the plastic covers on thetightening bolts; brush the threadsclean with a steel wire brush.

Lubricate the threads with a thinlayer of grease, e.g LUBRIPLATEFGL-2 or equivalent.

Mark the plate assembly on theouside by a diagonal line, or numberthe plates in sequence.

Measure and note the dimension A.Compare with code plate and PHEdocumentation for this same serialnumber.

6.2

7.,

8.

9.

10.

11.

12.

6 Opening

6.3

13 14(See page 6.5)

13 14(See page 6.5)

13 14(See page 6.5)

13 14(See page 6.5)

3

3

3

2

2

2

1

4

1

4

1

4

3

2

1

4

M6/M6-MFG & MX25-BFM ONLY HAS ONEBOLT TOP AND BOTTOM

P2 A10B TS6-M AM10 M10BM10M

FG X X X X

FM X

FD X

V8 P3 V13 V28 M10B M10BW M20-MV20 M10M M10DW

E X

FD X

FG X X X X

FM X

VG X

M3 P2 P3 V28 V45

EH XVG X

VLCH XFGFD X X

AM20AM20BAM20WAM20S M6

MX25B A15BWA 15B TS20-M AM20DW M6M M15M

FG X X X X X XFD X X XFL XFM X X XFS X

6Opening

6.4

M20-M

X

M20-MFG ONLY HAS ONE BOLTTOP AND BOTTOM

FG

M6/M6-MFG ONLY HAS ONE BOLT TOPAND BOTTOM

FGFDFMFS X

X XX

X

M10B

FD

M10BWM10M

X X

A20B

FD

AK20T200

X X

MX25B

XFLFG

M6M15B AK20 M6MM15F A20B T200 M6DW M30

V110

X X

6 Opening

6.5

NOTE: M30-FD, MA30-FG/FD, MX25-BFS, V280-FG/FDand V170-FD have a twenty bolt or larger pattern, use thispicture only as a guide. Start sequence numbers 5 and 6at the fourth bolt down on both sides.

FGFDHAFS

XX

XX X

MX25B

X

X

X

AX35 A35

AX30BW V110

X

X

FGFD

AX30B

ORDER BOLT NO. TO DIM.

1 1-2-3-4-5-6 1.05A2 1-2-3-4 1.10A3 1-2 OR 3-4 OPENING

If bolts are fitted with bearing boxes loosen andremove them. If not fitted with bearing boxes, thenfollow the pictures above.

Loosen the remaining bolts, alternately and diagonally, to bring length to 1.05A.

Remove bolts 5 and 6 completely.

Continue opening, alternately and diagonally.

Note: Skewing of the Pressure Plate during opening must not exceed 10 mm (2 turns per bolts) across the width and 25 mm (5 turns per bolts) vertically.

13

14

15

16

1615

13 14

13 14

1

4

3

2

1

4

3

2

15

4

36

27 8

AX30B M20M M30AX30BW A45

V170V280

XX

6Removal and insertion of plates

6.6

Brush the threads of the bolts clean, using asteel wire brush

Lubricate the threads with a thin layer ofgrease, e.g. LUBRIPLATE FGL-2 or equivalent.

3. 4.

Push the pressure plate against thesupport column.

Remove the plates. Stack them neatlyon a skid or pallet for easy transporting.

Hang the plates with their backs towardsthe pressure plate (the side without gas-ket).

REMOVAL OF PLATES

INSERTION OF PLATES

3.

4.

5.5.

1.

2.

6 Closing

Check that all the sealing surfaces (i.e.surfaces in contact with the heat trans-fer medium) are clean.

Check that the ring gaskets or liners,when fitted in connections, are in posi-tion and are in good condition.

Clean and lubricate the sliding surfacesof the carrying bar.

Inspect the pressure plate roller.Remove any debris from top surfaceof carrying bar.

Check against the drawing or flowsheet (provided with each heatexchanger) to make sure that theplates are hanging in the correct order.

Press the plate assembly together.

If the plates are correctly assembled,the edges form a “honeycomb” pattern.

If the plate pack has been marked onthe outside (fig. 6) check this.

6.7

1.

2.

3.

4.

5.

6.

7.

1. 4.

2.

7.3.

6.

6Closing

6.8

8 11(See page 6.11)

3

3

3

2

2

2

1

4

1

4

1

4

3

2

1

4

M6/M6-MFG & MX25-BFM ONLY HAS ONEBOLT TOP AND BOTTOM

1

4 2

3

5

6

14 (See page 6.11)

8 11(See page 6.11) 14 (See page 6.11)

14 (See page 6.11)8 11(See page 6.11)

8 11(See page 6.11)

V8 P3 V13 V28 M10B M10BW M20-MV20 M10M M10DW

E X

FD X

FG X X X X

FM X

VG X

M3 P2 P3 V28 V45

EH XVG X

VLCH XFG XFD X X

P2 A10B TS6-M AM10 M10BM10M

FG X X X X

FM X

FD X

AM20AM20BAM20WAM20S M6

MX25B A15BW A15B TS20-M AM20DW M6M M15M

FG X X X X X XFD X X XFL XFM X X XFS X

6 Closing

6.9

M20-M

X

M20-MFG ONLY HAS ONE BOLTTOP AND BOTTOM

FG

M6/M6-MFG ONLY HAS ONE BOLT TOPAND BOTTOM

FGFDFMFS X

X XX

X

M10B

FD

M10BWM10M

X X

A20B

FD

AK20T200

X X

MX25B

XFL

8 (See page 6.11) 11

4

31

3

2

2

1

4

3

24

1

3

2

1

4

3

24

1

3

24

1

5

6

1

4 2

3

6

5

8 (See page 6.11) 11

8 (See page 6.11) 11

8 (See page 6.11) 11

6

5 14 (See page 6.11)

14 (See page 6.11)

14 (See page 6.11)

14 (See page 6.11)

FG

M6M15B AK20 M6MM15F A20B T200 M6DW M30

V110

X X

6Closing

6.10

Note: See next page for closing instructions for all the models

14

8 11

118

14

1

4

3

2

1

7

3

6

2

5

4

8

1

7

36

2

5

4

1

4

3

28

NOTE: M30-FD, MA30-FG/FD, MX25-BFS, V280-FG/FDand V170-FD have a twenty bolt or larger pattern, use thispicture only as a guide. Start sequence numbers 5 and 6at the fourth bolt down on both sides.

FGFDHAFS

XX

XX X

MX25B

X

X

X

AX35 A35

AX30BW V110

X

X

FGFD

AX30B

ORDER BOLT NO. TO DIM.

1 1-2-3-4-5-6 1.05A2 1-2-3-4 1.10A3 1-2 OR 3-4 OPENING

AX30B M20M M30AX30BW A45

V170V280

XX

8. Place all the bolts that are fitted with bearingboxes in position. If not fitted with bearing boxesthen follow the pictures for your specific model.

9. Brush the threads of the bolts clean, using a steelwire brush.

10. Lubricate the threads with a thin layer of grease,e.g. LUBRIPLATE FGL-2 or equivalent.

11. Tightening is carried out alternately and diago-nally, as shown on the figure above.

12. Check the dimension A during tightening at thepositions of the bolts that are being used.Skewing of the pressure plate during tighteningmust not exceed 10mm (2 turns per bolt) acrossthe width and 25 mm (5 turns per bolt) vertically.

13. Nominal plate pack length A can be exceeded inexceptional cases, the tightening can be stoppedat the following dimensions

Plate pack length/plat Plate pack length

> 4 mm A + 1%> 3mm, < 4mm A + 1.5%

14. Place the other bolts in position.• Inspect the washers.

• When fully tightened, the bolts should all beequally tensioned.

• The difference between the plate pack lengthsmeasured at adjacent bolts should not exceed:

2mm when dimension A is < 1000mm

4mm when dimension A is > 1000mm

• The plate pack length at all bolts must not dif-fer by more than 1%

• If the unit does not seal fully, it can be tight-ened to the dimension A-1%.

IF DIMENSION A IS NOT REACHED WITH APPLI-CATION OF THE ABOVE STEPS:

• Check the number of plates and dimension A.

• Check that all the nuts and bearing boxes arerunning freely. If not, clean and lubricate orreplace.

• Fit all the bolts, and tighten alternately.

Closing6

6.11

Chlorine as growth inhibitor

Chlorine, commonly used as growth inhibitor in coolingwater systems, reduces the corrosion resistance ofstainless steels (including Hastelloy, Incoloy, Inconeland SMO).

Chlorine weakens the protection layer of these steelsmaking them more susceptible to corrosion attacksthan they otherwise should be. It is a matter of time ofexposure and concentration.

In every case where chlorination of non-titanium equip-ment cannot be avoided, ALFA LAVAL must be con-sulted.

Contact the following address:ALFA LAVALHeat Transfer Center5400 International Trade DriveRichmond, VA 23231Phone (804) 222-5300Fax (804) 236-3276

NOTE! Titanium is not affected by chlorine.

Mechanical cleaning after opening.

Soft brush and running water.NOTE! Avoid gasket damage.

Chemical cleaning of opened unit byusing:

• Nitric acid

• Sulfamic acid

• Citric Acid

• Phosphoric acid

• Complexing agents (EDTA, NTA)

• Sodium polyphosphates

CLEANING

INCRUSTATION - SCALING

• Calcium carbonate

• Calcium sulphate

• Silicates

High pressure hose.1. 2.

3.

Cleaning 7

7.1

Concentration max 4% by wt%Temperature max 140 Fo

2.1.

NOTE!Under no circumstances shouldHYDROCHLORIC ACID be usedwith STAINLESS STEEL PLATESand under no circumstancesshould HYDROFLUORIC ACID beused with TITANIUM PLATES.Water of more than 300 ppmChlorine may not be used for thepreparation of cleaning solutions.

It is very important that carryingbars and support columns made ofaluminum are protected againstchemicals.




• Nitric acid

• Sulfamic acid

• Citric Acid

• Phosphoric acid



CLEANING

SEDIMENT

• Corrosion products

• Metal Oxides

• Silt

• Alumina

• Diatomic organisms and their excriment of various colors.


3.

Cleaning7

7.2


The addition of surfactants can improvecleaning effect.

4.

1. 2.

NOTE!Under no circumstances shouldHYDROCHLORIC ACID be usedwith STAINLESS STEEL PLATESand under no circumstances shouldHYDROFLUORIC ACID be used withTITANIUM PLATES. Water of morethan 300 ppm Chlorine may not beused for the preparation of cleaningsolutions.

It is very important that carrying barsand support columns made of alu-minum are protected against chemi-cals.



CLEANING:

GROSS FOULING

• Seaweeds

• Wood chips/fibres

• Mussels

• Barnacles


Cleaning 7

7.3

NOTE: BACKFLUSHING OF THE UNOPENED HEAT EXCHANGERCAN SOMETIMES BE SUFFICIENTLY EFFECTIVE.

1. 2.






• Nitric acid

• Sulfamic acid

• Citric Acid

• Phosphoric acid



CLEANING

BIOLOGICAL GROWTH - SLIME

• Bacteria

• Nematodes

• Protozoa


3.

Cleaning7

7.4


1. 2.



7.5

Cleaning 7

• Oil residues

• Asphalt

• Fats

CLEANING


Hydrocarbon-based deposits may beremoved by using a soft brush and aPARAFFINIC or NAPHTHA-BASEDsolvent (e.g. KEROSENE).

Dry with a cloth or rinse with water.

NOTE!Gaskets in natural, butyl and EPDMrubber swell in these media.

Contact time should be limited to 0.5hour.

THE FOLLOWING SOLVENTS SHOULD NOT BE USED

• Ketones (e.g. Acetone, Methyletylketone, Methylisobutylketone)

• Esters (e.g. Ethylacetate, Butylacetate)

• Halogenated hydrocarbons (e.g. Chlorothene, Carbon tetrachloride, Freons)

• Aromatics (e.g. Benzene, Toluene)

1. 2.

7.6

7 Regasketing

ALFA LAVAL has two types of glue for field repairs - GC11 andGC8 for repairs and exchange of gaskets in plates. A specialglue is recommended for viton and silicone gaskets.

GC11

• A two-component, cold curing epoxy gluewhich gives a strong joint for higher temper-atures.

• Future removal of gaskets usuallyrequires heating or freezing of the joint.

• The shelf life is limited to approx. 1 yearwhen stored at room temperature but can beprolonged when kept in a refrigerator.

GC8

• A single-component rubber-based sol-vent adhesive.

• Is normally used for repair work in anuncured condition.

• Can be used for operating temperaturesbelow 200 F

• For operating temperatures above 200 Fand oil coolers/heaters, the glued jointsshould be cured at 200 F for one hour.

• Future removal of the gasket can usuallybe carried out without heating of the cementjoint.

• The storage life at room temperature isabout two years. This period can be extend-ed after checking the glue.

SEPARATE GLUING INSTRUCTIONS WILL BEDELIVERED TOGETHER WITH THE GLUE.

ALFA LAVAL RECONDITIONING SERVICE

In addition to supplying genuine gaskets for yourplate heat exchangers, we are able to provide a“SPECIALIZED PLATE RECONDITIONINGSERVICE” to quickly and efficiently meet yourservice requirements.

Our reconditioning service includes a liquid nitro-gen debonding process with chemical cleaning,crack detection and regasketing usinga special epoxy/phenolic resin adhesive.

This regasketing process requires special ovencuring of the cement to ensure the strongest

possible bond strength between plate and gas-ket, similar to the process used during manu-facture. This is one reason why our service isguaranteed.

In most cases our reconditioning service hasproved more economical and much fasterwhen compared with on-site regasketing meth-ods.

For further details, please contact your localALFA LAVAL REPRESENTATIVE.(See Section 1)

7.7

7Regasketing

The Clip-on gasket -a glue-free gasket system

The Clip-on gasket is attached to the plate by twogasket prongs which slip under the edge of the plateto hold the gasket securely in alignment in the gas-ket groove.

The prongs are situated at regular intervals aroundthe periphery of the plate.

When the plate heat exchanger is then assembledand tightened, the gasket provides a tight sealaround the plate.

The Clip-on gasket in the gasket groove.

NOTE!

Before closing of the equipment:Check that the two gasket prongsare in correct position.

7.8

7 Regasketing of Snap-On GasketsTHE PROCEDURES (2-7) ARE NOT NECESSARY FOR DOING A SMALL QUANTITY OF PLATES.THESE PROCEDURES WILL INCREASE SPEED OF REGASKETING OF LARGE QUANTITIES OF PLATES.

PREPARATORY PROCEDURES

Pull the old gasket off the plate andclean the groove, if necessary.

Place a flat sheet of plywood (somewhatlarger than the PHE plate) on the table.

Place the PHE plate on the boardwith gasket groove upwards and fixfirmly. Placing cylindrical pins in theplank at the carrying bar slots.

Make marks in the plank at all loca-tions for gasket “snap-on”.

Remove the plate.

Drill holes approx. 7mm dia and 10mm deep in the plank at the markedspots. The plank is now a practicaltool for regasketing of larger numbersof plates.

Replace PHE plate on the board inexactly the same location as at 3above.

1.

2.

3.

4.

5.

6.

7.

5.

6.

1.

2.

3.

7.

4.

7.9

7Regasketing of Snap-On Gaskets

FASTENING OF THE “SNAP-ON” GASKET

Place the gasket, with the “snap-on” pro-jections downwards, in the gasketgroove.

Place the ring gaskets in the groove andfix them with the T-flap.

Insert the tool point into the recess in theprojection.

Push the projection through the hole in the plate.

Remove the tool point, and the projec-tion is now “snapped on”.

Repeat for all projections, and the gas-ket is “snapped on”.

8.

9.

10.

11.

12.

13.

NOTE!BEFORE CLOSING OF THE EQUIP-MENT: CHECK THAT THE T-FLAPSARE IN CORRECT POSITION.

10.

13.

12.

11.

7.10

7 PARALLEL FLOW UNITS

The End Plate II Gasket is formed by cutting (2) channel gaskets(as shown below) and gluing the gaskets to the first plate.

The (2) half channel gaskets should be glued to the end plate withGC-8 glue: or double sided tape (GC-1). The (4) port gasket areasare critical because these gaskets will be in contact with the processfluids.

+ =

7.11

7DIAGONAL FLOW UNITS

The End Plate II Gasket is formed by cutting (2) channel gaskets(as shown below) and gluing the gaskets to the first plate.

The (4) parts of the channel gaskets should be glued to the end plate with GC-8 glue: or double sided tape (GC-1). The (4) port gasket areas are critical because these gaskets will be in contact with the process fluids.

+ =

8 Fault detection

SYMPTOM

LEAKAGE between plates and frame.

• Relocate gasket.

• remove foreign matter.

• replace connection lining if applicable.

Remove anything disturbing the jointbetween gasket and pressure plate surface.

A perforated end plate must be replaced.

ACTION CORRECTIONS

1.

2.

3.

Mark with a felt tip or similar marker, mark thearea here the leakage seems to be, and openthe heat exchanger

Investigate the gasket condition of the endplate and the connection if applicable, lookfor dislocation, foreign objects, scars andother damage to the gasket surfaces.

Check the plate itself for cracks or holes.

Check the surface of the pressure plate forunevenness, foreign objects sticking to it,etc. that might spoil the joint between thegasket and the adjacent surface.

SYMPTOM

LEAKAGE between flange and frame.

ACTION CORRECTIONS

Disconnect the flange, and look for mis-alignment between flange and connec-tion, dislocated or damaged gasket, for-eign objects on the surface of the gasketor 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

1. 1.

1.

8.1

• Relocate gasket.• Re-cement loose gasket, if applicable.• Replace damaged gasket.

A damaged plate must in most cases betaken out for repair or replacement. If it isa regular plate with 4 holes: take the dam-aged plate and the 4-hole plate just in frontor just behind it out of the plate pack. Theheat exchanger can now be reassembledand put back in service PROVIDED THEPLATE PACK IS TIGHTENED TO A NEWMEASUREMENT, WHICH IS EQUAL TOTHE ONE ON THE DRAWING, REDUCEDBY TWO TIMES THE SPACE REQUIREDPER PLATE. CONTACT ALFA LAVAL FORASSISTANCE IN THE RECALCULATIONIF NECESSARY.The small reduction of the heat transferarea is normally of no importance, at leastnot for a short period of time.• Insufficient tightening must be corrected

- see the drawing.

Damaged hanger recesses must berepaired if possible, or the plate replaced.For temporary arrangement with reducednumber of plates - see paragraph 2 above.

Incorrect sequence of plates must be cor-rected (A-B-A-B-..). MAKE SURE THATNO PLATE HAS BEEN DAMAGED,BEFORE REASSEMBLING THE PLATEPACK!

Perforated plates must be replaced. Fortemporary solution, see paragraph 2.

8Fault detection

8.2

On a Plate Heat Exchanger specially designed for high temperature duties, extremeand sudden temperature drops may sometimes cause a temporary leakage. A typicalexample is a sudden shutting-off of the hot medium flow. The heat exchanger willnormally seal again, as soon as the temperatures of the equipment have stabilized.

NOTE:

Mark the leakage area with a felt tip marker onthe two plates next to the leakage, check andnote the length of the plate pack betweeninside frame plate and inside pressure plate,and then open the heat exchanger.

Check for loose, dislocated or damagedgasket.

Check for plate damage in the area, andalso check plate pack length against thedrawing to see if possible plate or gasketdamage could be caused by overtighteningof the plate pack, or if the leakage itself maysimply be caused by insufficient tightening.

Check hanger recess at both plate ends fordeformations, which could cause misalign-ment between the plates.

Make sure that the plates are hanging cor-rectly as A-B-A (see SECTION 4A or 4B).

Check for perforation of the plate (corro-sion).

ACTION CORRECTIONS

1.

1.

2.

2.

3.

3.

4.

4.

5.

5.

SYMPTOM

LEAKAGE between plates tothe outside.

8 Fault detection

8.3

ACTION CORRECTIONS

1. 1.

2.

3.

4.4.

5.5.

SYMPTOM

LEAKAGE between plates.

Check that the piping is connected to theheat exchanger at correct locations.

Open the lower connection on one side, raisepressure on the other side and by lookinginto the open connection try to detect any liq-uid from the pressurized side leaking in, andif so - approximately how far into the platepack the leakage is located. If no leakage isdetected, the reason for the mixing of mediamust be sought elsewhere. (see paragraph5).

If a leakage was detected, note the positionof the leakage along the plate pack and thenopen the plate heat exchanger.

Before starting on the plates themselves,check that the corner areas between the ringand the field gaskets are clear, that the leak-age slots are open. This ensures that anyleakage is out of the plate heat exchangerand is to atmosphere. Therefore no pressurecan build up to force the media across thegasket sealing off the other liquid.

If it has not been possible to locate the leak-age as described in par. 2 above, it will benecessary to check each single plate for pos-sible perforations, using any of the followingmethods:

• put a strong light behind the plate andwatch

for light coming through fine holes orcracks.• use a magnifying glass to check suspect

area.• use a chemical penetrant, after having

cleaned the plates well.

Relocate piping to correct connections.

All deposits or material which can blockthe free exit from the area must beremoved. If the leak channels of the gas-ket have been destroyed, they must bereopened with a suitable tool, or the gas-ket replaced.

Plates with holes must be replaced. ThePHE may be temporarily operated with areduced number of plates. See “LEAK-AGE between plates to the outside”.

8Fault detection

8.4

ACTION CORRECTIONS

1. 1.

1.1

1.2

3.

2.

SYMPTOM

PRESSURE DROP PROBLEMS,

Pressure drop has increased

Check that all valves are open includingnon return valves.

Measure the pressure just before andjust after the heat exchanger, and theflow rate. For viscous media a mem-brane manometer with a diameter of atleast 30 millimeters should be used.Measure or estimate the flow rate if pos-sible. A bucket and a watch showingseconds may be sufficient for small flowrates. For larger flow rates, some type offlowmeter is required. Compare thepressure drop observed with the onespecified for the actual flow rate. (seeplate print out)

If the pressure drop is higher thanspecified, the temperature programshould also be checked:

If the thermometer readings corre-spond to those specified, the heattransfer surface is probably cleanenough, but the inlet to the heatexchanger may be clogged bysome objects.

If the thermometer readings areNOTcorresponding to those specified,heat transfer is obviously droppingbelow specifications, because ofdeposits on the heat transfer sur-face, which at the same time alsoincrease the pressure drop, sincethe passage becomes narrower.

If the pressure drop corresponds tothe specifications, there is no needfor any action.

If the pressure drop is lower thanspecified, the pump capacity is toosmall or the observation is wrong.

See next paragraph.

Open the PHE and take outwhatever is clogging the pas-sage, or use the back-flush sys-tem - if there is one - to rinse outthe cloggings.

If a “cleaning-in-place” systemisavailable, follow the instructionand use it to wash out thedeposits. If not, open the PHEand clean the plates.

See pump instruction manual.

1.1

1.2

2.

8 Fault detection

8.5

ACTION CORRECTIONS

SYMPTOM: HEAT TRANSFER PROBLEMS

The heat transfer capacity is dropping

Measure temperatures at inlet and outletsand also flow rates on both media, if possi-ble.At least on one of the media, both tempera-tures and the flow rate must be measured.Check to see if the transferred amount ofheat energy corresponds to the specifica-tions.

If great precision is important, it will be nec-essary to use laboratory thermometers withan accuracy of 0.2 degrees Fahrenheit, andalso to use the best equipment available forflow measurements.

If the heat transfer capacity of the equipmenthas dropped below specified values, the heattransfer surface must be cleaned. Either usethe “cleaning-in-place” arrangement if provid-edor open the heat exchanger for visual inspec-tion and manual cleaning.

NOTE: Contact the Alfa Laval Sales &Service Division for CIP recommendations(See Section 1).

9Supplementary Parts

9.1

THE PARTITION PLATE - for special cases only.

If for instance, the thermal program requires that atleast one of the media is to flow in more than onegroup through the plate package, there will be heattransfer plates with fewer than 4 holes.

To prevent the thin metal collapsing under the dif-ferential pressure, un-punched corners requireextra support.

The extra support is provided by a partition plate -approximately the size of a channel plate - made ofabout 1/4” - 3/4” thick plate material with lined holeswhere a free passage is required.

The partition plate is suspended from the carryingbar. Where partition plates are required, in unitswith 8” ports or larger, there will be one at everyturning point in a multi-grouped plate package.

Example only

plate heat exchanger - mahan's thermal products,...

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