PHE Mannual

Plate heat exchanger

Types M3–M20

Table of contents

Chapter Page

Warning 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

To the owner 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

The data plate – and the identification of the apparatus 5. . . . . . . . . . . .

General 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Storage 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Packing list, unpacking and lifting 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lifting 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Raising of PHE 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Foundations 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Installation 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pipes 15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Shut off valves 15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Connections on the pressure plate 15. . . . . . . . . . . . . . . . . . . . . . . . . . . .

The main components and their functions 16. . . . . . . . . . . . . . . . . . . . . . . . Function 16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Marking of plates 17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Plates 19. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Drawing 21. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Platage specification 22. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gaskets 23. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . How it works 25. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Heat transfer 26. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pressure drop 27. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The double–wall plate heat exchanger 28. . . . . . . . . . . . . . . . . . . . . . . . .

Operation 29. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Starting up 29. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Unit in operation 31. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Shut–down 31. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The risks of not complying with the start–up and shut–down procedures 32. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Opening and closing of the plate package 33. . . . . . . . . . . . . . . . . . . . . . . . Opening 33. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Closing 38. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Removal and insertion of plates 43. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Table of contents

Chapter Page

Maintenance 45. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Chlorine as growth inhibitor 45. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cleaning 46. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Regasketing 51. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Regasketing of Clip–on gaskets 52. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Fault detection 53. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Leakage between plate pack and frame 53. . . . . . . . . . . . . . . . . . . . . . . Leakage between flange and frame 54. . . . . . . . . . . . . . . . . . . . . . . . . . . Leakage between plates to the outside 55. . . . . . . . . . . . . . . . . . . . . . . . Mixing of media 57. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pressure drop problems 58. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Heat transfer problems 59. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Supplementary parts 60. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Instrument ring 60. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The partition plate – for special cases only 61. . . . . . . . . . . . . . . . . . . . .

Spare parts 62. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Identification and ordering of spare parts 62. . . . . . . . . . . . . . . . . . . . . . .

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Warning!

CAUTION!

To avoid hand injuries owing to sharp edges,protective gloves should always be wornwhen handling plates and protective sheets.

PROTECTIVE SHEETS Ref: chapter 9

To avoid injuries and damages, follow the in-structions in this manual. Also comply withapplicable local safety regulations.

To prevent from injuries or damages in case ofleakage and spouting liquid or steam, whennecessary we can supply protective sheet forall plate heat exchangers.

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To the owner

Dear owne r,

This Instruction Manual is your instant guide,when dealing with your Alfa Laval Plate HeatExchanger in various situations. Alfa Laval ad-vises you to study it carefully, and – above all– to ensure its availability to those who install,maintain and operate the apparatus on a dailybasis. This manual will be of no value to you ifit is not available at a time when your person-nel needs it.

Alfa Laval will not be responsible for anybreakdown of the equipment caused by the

owner’s failure to follow the instructions of thismanual.

If you nevertheless should have a problemwith your Alfa Laval Plate Heat Exchangerwhich is beyond the scope of this manual, donot hesitate to turn to your Alfa Laval repre-sentative. We can help you, wherever you arein the world.

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The data plate – and the identification of the apparatus

Type and manufacturingnumber

A data plate is fixed to the apparatus and gives the following information

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2 The data plate – and the identification of the apparatus

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This instruction manual has been issued forone particular apparatus and carries themanufacturing number of that apparatus onthe upper line on the front cover.

A design drawing of the apparatus is located inthe inside pocket of the back cover of thismanual.

• Whenever using the manual, check first thatthe manufacturing number on the front cov-er is identical to that on the data plate of theapparatus.

• In all correspondence with Alfa Laval,please refer to the manufacturing number,for true identification of the apparatus.

• All parts of the plate heat exchanger areidentified by a part number. Whenever con-tacting Alfa Laval about a part, be sure tostate its identification number (from partslist in this manual).

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General

Storage

In this section, names of heat exchanger partsare mentioned for the first time. For your infor-mation, see the first paragraph of Section 4.

A

Unless otherwise agreed, Alfa Laval deliversthe plate heat exchanger ready to be put inservice upon arrival. This means that the platepackage is tightened to its correct measure-ment A.

Should it be necessary, however, to store theapparatus for a longer period (1 month ormore) before, certain precautions should bemade in order to prevent unnecessary dam-ages of the equipment:

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

NOTE!There should absolutely not be any ozone–producing equipment in the room, like elec-tric motors or arc–welding equipment, sinceozone destroys many rubber materials(cracking).

Do not store organic solvents or acids in theroom and avoid heat– or ultraviolet radiation.These may destroy the rubber materials.

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The best solution is often to leave the heat ex-changer in the packing case until it is time for installation.In this case Alfa Laval should be informed, inorder that proper preparation can be done prior to packing.

To wrap the plate package with a non–tran-sparent plastic film is a good precaution.

The tightening bolts should be well coveredwith a good rust preventing coasting, like EssoRustban 326 or similar, and if not connected tothe pipe system, the connections should becovered.

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.

Also, if for any reason the heat exchanger isclosed down and taken out of service for along period, it is recommended to follow theadvice above, even if the apparatus is notmoved from the location.The heat exchanger should be drained anddepending on the media processed, it is re–commended to rinse and dry it, before it is leftfor storage.

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3General

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Packing list, unpacking and lifting

Packing list and unpacking

The packing list is attached to the goods.

For safe transport it is necessary to deliver in-struments, valves etc. unmounted. Pleasecheck all parts against packing list, handlefragile parts with care.

Lifting

When lifting the unopened packing case (orskid) please observe the markings on the caseindicating where to place lifting hooks.The centre of gravity of the lead is importantand is marked on the topside of the case; theactual centre of gravity is located on a verticalline directly below this mark.Alfa Laval generally advises customers in ad-vance on how the heat exchanger has beenplaced inside the crate.

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Lifting

If you are to lift the heat exchangeritself, straps should be used.They should be placed as shown onthe picture.

WARNING!Never lift by the connectionsor the studs around them.

PHE–Types M3, M6, M10, M15, A15, AK20, AM20, M20 and A20

3 General

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Raising of PHE

Remove the support feet.

Place two timber beams on the floor.

Lift the heat exchanger off pallet using e.g.strops.

Place the heat exchanger on timber beams.

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Place strops round one bolt on each side.

Lift the heat exchanger from the timber beams.

Bolt on the support feet.

Lower the heat exchanger to horizontal andplace on floor.

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3 General

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Foundations

All information necessary for the preparation ofthe foundation appears from the data sheetprovided by Alfa Laval.

In some cases it may be practical to place theheat exchanger in a drainage box , with ca-pacity for the total volume of the heat ex-changer (installation onboard a ship, whenprocessing corrosive liquids etc.). The outlet ofthe drainage box should be generously dimen-sioned, not less than 50 mm (2¨) diameter.

Installation

Before connecting any piping to the heat ex-changer, make sure that all foreign objectshave been rinsed out of the system!

Recommended free space for openingand closing.

As will appear from the dimension drawingprovided by Alfa Laval, and from the pictureabove, it is necessary to leave free spacearound the apparatus, to give access andmake future service possible. Except for aplace to put the plates, if removed from theheat exchanger, no further space is requiredfor servicing the apparatus.

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This field should be kept freefrom fixed installations.

NOTE!The measurements given in the picture arerecommended by Alfa Laval, to provide rea-sonably good working conditions, during in-stallation of the heat exchanger as well as forfuture maintenance and service. If floorspace is restricted then the dimensions sug-gested can be reduced, and it is left to thepurchaser to decide just how much accessspace can be left.

3 General

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Pipes

When connecting the pipe system to the heatexchanger make sure that no stress or strainis imposed, by the pipe system, on to the heatexchanger.

Shut off valves

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

Connections on the pressure plate

Some plate heat exchangers may have con-nections also in the pressure plate. In suchcases, it is important to check against thedrawing or the data print that the plate packhas been tightened to the right measurementbefore the pipe is connected.

An elbow should be flanged to the connectionin the pressure plate, directed upwards orsidewards, and with an other flange locatedjust outside the contour of the heat exchanger.It is then convenient to disconnect this secondflange – and not the one attached to the pres-sure plate – when the heat exchanger is to beopened.

Venting of both sides of the heat exchangermust be provided. This is important and en-ables air to be drawn from the system duringcommissioning. It also enables air or gas to beremoved during operation.

Frame plate

Support columnThe two bars are sus-pended between the frameplate – to which in mostcases the piping is con-nected, and a support col-umn .

Carrying bar

Guiding barThe plates hang from acarrying bar and arekept in line by a guid-ing bar at the lowerend.

ConnectionsHoles matching the piping leadthrough the frame plate, permittingthe media to enter into the heat ex-changer.Threaded studs around the holes se-cure the pipes to the apparatus.Depending on the application, metal-lic or rubber–type linings may pro-tect the edges of the holes againstcorrosion.

Tightening boltsWith the package of thin plates hang-ing between the frame plate and thepressure plate, a number of tighten-ing bolts are used to press the thin-plates together, to bring them into me-tallic contact, and to pressure the gas-kets, enough to seal off the narrowpassages which have now beenformed between the plates

Channel plates

GasketThese plates are called channelplates . A groove along the rim of theplate and around the ports hold a gasket , usually made of a rubber–type material.

Heat is transferred through the sur-face which is contained by the gasket,except for some small areas near thecorners.

The number of plates in the packageof your heat exchanger is determinedby the size of the heat transfer surfacerequired.

Pressure plateA steel plate called the pressureplate is also hung on the carrier barand is moveable, as are the heattransfer plates. In some cases pipemay be connected to the pressureplate.

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The main components and their functions

Function

In Alfa Laval Plate Heat Exchangers, heat istransferred from one medium to anotherthrough thin metal plates which have beenpressed into a very special pattern.

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The main components and their functions4

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Marking of plates

Plate types: M3, M6–M, M10–M, M10–B, M15–B

Seen as A–plate from the gasket side.

Metallic article number only on– Variant holed plates– All end plates– Transition plate

– Marking charge– Coil number

– Plate type– A–Side / Manufacture year

The main components and their functions 4

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Marking of plates

Plate type: M20-M

Seen as A–plate from the gasket side.

– Complete article number– A–Side– Manufacture year

– Marking charge– Coil number

– Nation – Plate type


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Plates

A B–plate is a platehanging with thechevron pointing up-wards.

Studying the pictures, you will observe that on a plate hanging vertically, the gasket rests in a groove which includes the heat transfer area

or two corners onthe right side.

We decide that we will name the plates afterthese two situations.

An A–plate is aplate hanging withthe chevron pointingdownwards.

Smaller rings surround the two remainingcorners.

and two cornerson the left side.


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PlatesIt also appears that if we turn an A–plate upsidedown we will have a B–plate:


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Drawing

The drawing is in the inside pocket of the back cover.It gives specific informations about the plate heat exchanger.

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1. Manufacturing number

2. Type of PHE

3. Customer

4. Alfa Laval representative through whom the heat exchanger was purchased

5. Media according to the order

6. Location of inlet connections

7. Inlet temperatures

8. Location of outlet connections

9. Outlet temperatures

10. Liquide volume in the PHE

11. Type of materials used for plates and gaskets

12. – Size of heat transfer surface area– Plate grouping

13. Type of materials used for connections

14. The plate packet length A

15. – Max. test and design pressure – Max. temperature


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Platage specificationOn the following page – or pages – is a listingof the plate package, specifying for each platein sequence from the frame plate to the pres-sure plate:

The flow direction along the plate

The plate identification number

The identification number is also the SPAREPART ORDERING NUMBER

The corners where holes have been punched

See also chapter 6 Removal and insertion ofplates.


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Gaskets

The GASKET is moulded in one piece. Thematerial is normally an elastomer, selected tosuit the actual combination of temperature,chemical environment and possible other con-ditions to be considered.

3 Links

1 One field gasket

2 Two ring gaskets

Gasket types:– Glued– Clip–On

The one–piece gasket is described asconsisting of:

The field gasket is by far the larger part con-taining the whole heat transfer area and thetwo corners connected to it, while the ringgaskets seal off the remaining two corners.

These three pieces are held together by afew short links, which have no sealing func-tion at all – their purpose is simply to tie thepieces together, and to add some support incertain areas.


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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 opening the area between thefield and ring gaskets to atmosphere. Anyleakage of media across either gasket there-fore escapes from the heat exchanger throughthe slots.

It is important that these openings are not per-mitted to plug. If that should happen, there is arisk that in case of a leakage in that region ofthe plate, there might be a local pressurebuild–up, which could let one medium leakover and mix with the other.

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


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How it works

When a package of plates are pressed togeth-er, the holes at the corners form continuoustunnels or manifolds, leading the media (whichparticipate in the heat transfer process) fromthe inlets into the plate package, where theyare distributed into the narrow passagesbetween the plates.

Because of the gasket arrangement on theplates, and the placing of A and B plates alter-nately, the two liquids enter alternate pas-sages, e.g. the warm liquid between odd num-ber passages, and cold liquid between evennumber passages.

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

During the passage through the apparatus, thewarmer medium will give some of its heat en-ergy to the thin wall, which instantly looses itagain to 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.


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Heat transfer

The purpose of the apparatus is to transferheat from one medium to an other, and heatpasses very easily through the thin wall sepa-rating the two media from each other. The novel pattern into which the plate materialhas been formed not only gives strength andrigidity, but greatly increases the rate of heattransfer from the warmer medium to the metalwall and from the wall to the other medium. This high heat flow through the walls can beseriously reduced by the formation of depositsof various kinds on the wall surfaces. The pattern of corrugation on Alfa Laval platesmentioned above induces highly turbulent flow.The turbulence gives strong resistance to theformation of deposits on the plate surface; itcannot always eliminate fouling. The deposits may increase the total ”wall thick-ness” substantially, and they consists of mate-rials that have a much lower thermal conduc-tivity than the metal plate. Consequently alayer of deposits can severely reduce the over-all heat transfer rate. The deposits will be considered under thechapter of Maintenance and Cleaning .At this point we will only establish that this foul-ing is unwanted and can under certain circum-stances, be harmful to the heat exchanger,because corrosion may occur under the de-posits.


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Pressure drop

Pressure drops are wasted energy.

All pipe–systems – and equipment included inthem – offer resistance to media flowingthrough them.

Some pressure drop is unavoidable, but for agiven apparatus it should be kept as close aspossible 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 apparatus.

It is clear that the fouling of the surfaces is un-desirable.Larger particles and fibres may also be drawninto the heat exchanger and clog it, if strainersor other means of protection have not beenprovided for.

A reduced ability by the heat exchanger tohold the desired temperatures, in combination

with an increased pressure drop on any of themedia, indicates that fouling or clogging is tak-ing place.

For corrective action, study Maintenance andCleaning .

In the unlikely event of leakage of any cause,one of the two media will appear externally.Should a failure occur, whether it is related tothe plate, gasket or seal weld, the ensuing leakwill be easily visible on the outside of the heatexchanger. For example:

1 A hole in one of the double plates will result in ex-ternal leakage from between the double–plate

pair

2 A gasket defect will cause an external leak, eitherdirectly from the peripheral gasket or from the

gasket vents open to the atmosphere

3 A defect weld will cause external leakage to ap-pear either from the gasket vents or from between the plates at the site of the failure.


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The double–wall plate heat exchanger

External leakage if hole occurs in one plate

External leakage ifweld is defect

Welded porthole

Design and construction

The Double–wall plate heat exchanger workson the same principle as a conventional plateheat exchanger but differs in that the singleplates between the two media are replaced byplate pairs consisting of two identical plates

stacked on top of each other and weldedaround the portholes. The channels thenformed by assembling welded plate pairs in aplate pack are conventional channels sealedby gaskets in the traditional manner.

In the unlikely event of leakage of any cause,one of the two media will appear externally.Should a failure occur, whether it is related tothe plate, gasket or seal weld, the ensuing leakwill be easily visible on the outside of the heatexchanger. For example:

1 A hole in one of the double plates will result in ex-ternal leakage from between the double–platepair

2 A gasket defect will cause an external leak, eitherdirectly from the peripheral gasket or from thegasket vents open to the atmosphere

3 A defect weld will cause external leakage to ap-pear either from the gasket vents or from between the plates at the site of the failure.

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Operation

Starting up

A

Before starting up for the first time or aftera long time of close–down: Make sure thatthe plate pack is compressed to the rightmeasurement A! Check with the Data–Print,which is located in the inside pocket of theback cover.

NOTE!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 to avoiddamages.This applies not only for the heat exchangerbut also for the pipe system itself and everypiece of equipment included in it.

This should be kept in mind whenever a ma-noeuvre is to be carried out, including startingup of the pumps in the system.

Before starting any pump, check whether in-structions exist, telling you which pump shouldbe started first.

Check that the valve between the pump andthe apparatus, controlling the flow rate of thesystem which you are about to start up isclosed.

Check that the valve at the exit – if there is one – isfully open.

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Open the vent.

Start the pump.

Open the valve slowly.

When all air is out, close the vent.

Repeat the procedure for the other media.

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Unit in operation

Any adjustment of the flow rates 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 a

change of some of the temperature conditions,the heat load or by fouling.

As long as the apparatus is operating to satis-faction, it should be left without any interfer-ence.

Shut–down

If the heat exchanger is going to be shut down– or if for any reason at all the pumps are to bestopped – the following procedure should befollowed:

First establish whether instructions exist as towhich side should be stopped first.

Slowly close the valve controlling the flowrate of the pump you are about to stop.

When the valve is closed, stop the pump.

Repeat the procedure for the other side.

Poor quality cooling water may be hazardousto metallic materials. Typical examples are cor-rosion of stainless steels and nickel alloys.

If for any reason the heat exchanger is shutdown for a longer period (more than a numberof days), it should be drained, and dependingon the media processed, it is recommendableto rinse and dry it.

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The risks of not complying with the start–up and shut–down procedures

A liquid in motion in a pipe system representsa lot of energy, and it must be very carefullydealt with.

Particularly when the fluid is stopped it is im-perative that this is done smoothly.

NOTE!For this reason fast–closing valves shouldnot be used unless the pipes of the systemare very short.

Valves must be operated gradually. The longerthe pipes and the higher the flow rate, themore important this becomes.

WATER HAMMER is the name given to ashort–lasting pressure peak, travelling alongthe pipe as a wave at the speed of sound, andresulting from a sudden deceleration of the mo-tion of the fluid in a closed system.

Thus, it is usually related to the shutting downof a system. However, when starting up a sys-tem with open valves and empty pipes, the fluidmay burst into some obstacle, like a fine–meshstrainer, a flow meter or a heat exchanger,causing a sudden reduction of the flow velocity– if not a complete halt –, and so we may havethe conditions of a Water Hammer.

In the worst case, the pressure surge causedby such a sudden stop of the motion of a fluid,can be several times the normal pressure ofthe system.

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

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Opening and closing of the plate package

Opening

Slowly close the valves on the inlets. Shut offthe inlet side, closing the highest pressure first.

Switch off pumps.

Close the valves on both outlets.

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6 Opening and closing of the plate package

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Opening

If the heat exchanger is hot, wait until it hascooled down to about 40°C

Drain.

Dismantle any pipe bends connected to thepressure plate, so that it can be moved freelyalong the carrying bar.

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6Opening and closing of the plate package

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Opening

Inspect the sliding surfaces of the carrying barand wipe clean.

Inspect pressure plate roller.

Pull back the plastic covers on the tighteningbolts; brush the threads clean with a steel wirebrush.

Lubricate the threads with a thin layer ofgrease, e.g. Gleitmo 800 or equivalent.

7

8

9

10


36

Opening

Mark the plate assembly on the outside by adiagonal line, or number the plates in se-quence.

A

Measure and note down the dimension A.

11

12


37

Opening (PHE–Types M3, M6, M10, M15, AM20, A15–BFM, M20, AK20)

Order Bolt No. To dimension

12

1–2–3–41–2 or 3–4

1.05 AOpening

Bolts which are not fitted with bearing boxesare loosened and removed.

The pairs of bolts that are fitted with bearingboxes are opened alternately and diagonally,as shown in the figure above.

Skewing of the pressure plate during openingmust not exceed 10 mm (2 turns per bolt)across the width and 25 mm (5 turns per bolt)vertically.

13

14


38

Closing

Check that all the sealing surfaces (i.e. sur-faces in contact with the heat transfer medium)are clean.

Check that the ring gaskets, when fitted in con-nections, are in position and are in good condi-tion.

Clean and lubricate the sliding surfaces of thecarrying bar.

1

2

3


39

Closing

Inspect the pressure plate roller.

Check against the data printout (located in theinside pocket of the back cover) to make surethat the plates are hanging in the correct order.

Press the plate assembly together.

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

If the plate pack has been marked on the out-side (fig.6) check this.

45

6

7


40

Closing (PHE–Types M3, M6, M10, M15, AM20, A15–BFM, M20, AK20)

Order Bolt No. To dimension

12

1–2 or 3–41–2–3–4

1.10 AA

Place the bolts that are fitted with bearingboxes in position.

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

Lubricate the threads with a thin layer ofgrease, e.g. Gleitmo 800 or equivalent.

Tightening is carried out alternately and diagonally, as shown on the figure above.

8

9

10

11


41

Closing

A

A

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

Nominal plate pack length A can be exceededin exceptional cases, the tightening can bestopped at the following dimensions:

Plate pack length/plate Plate pack length

>4 mm A + 1 %

>3 mm, <4 mm A + 1,5 %

<3 mm A + 2 %

NOTE!When a pneumatic tightening device is used,it should be set at the maximum torque ac-cording to table at the next page. DimensionA must, however, still be measured duringtightening.

12


42

Closing

Max tightening torque

Boltsize

Bolt with bearing box

Bolt with washers

M24

M30

M39

M48

1300

2100

130

210

450

900

2000

3300

45

90

200

330

Nm Kpm Nm Kpm

When the bolts are tightened by hand using awrench, the tightening moment is estimated.

Place the other bolts in position.

• Inspect the washers.

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

• The difference between the plate packlengths measured at adjacent bolts shouldnot exceed:

2 mm when dimension A is <1000 mm

4 mm when dimension A is >1000 mm

• The plate pack length at all bolts must notdiffer with more than 1%.

• If the unit does not seal fully, it can be tight-ened to give dimension A–1%. The maxi-mum tightening torque must not, however,be exceeded.

If dimension A is not reached with application of maximum tighteningtorque

• Check the number of plates and dimensionA.

• Check that all the nuts and bearing boxesare running freely. If not, clean and lubricateor replace.

• Fit all the bolts, and tighten alternately.

13


43

Removal and insertion of plates

Removal of plates

Push the pressure plate against the supportcolumn.

Remove the plates.

1

2


44

Insertion of plates

Hang the plates with their backs towards thepressure plate (the side without gasket).

Read the table of plates from the bottom andup, since in fact you are starting at the end ofthe plate pack, instead of the beginning, whendoing this.

3

4

45

Maintenance

! Caution!

Chlorine as growth inhibitor

Chlorine, commonly used as growth inhibitor incooling water systems, reduces the corrosionresistance of stainless steels (including Hastel-loy, Incoloy, Inconel and SMO).

Chlorine weakens the protection layer of thesesteels making them more susceptible to corro-sion attacks than they otherwise should be. Itis a matter of time of exposure and concentra-tion.

In every case where chlorination of non–tita-nium equipment cannot be avoided, Alfa Laval Thermal AB must be consulted.

Contact the following address:

Alfa Laval Thermal ABDepartment TPI-RMBox 74S–221 00 LUND, Sweden

NOTE!Titanium is not effected by chlorine.

7

7 Maintenance

46

Cleaning

Gross fouling

• Seaweeds

• Wood chips/fibres

• Mussels

• Barnacles

Mechanical cleaning after opening

Soft brush and running water.

NOTE!Avoid gasket damage.

High pressure hose.

Back–flushing of the unopened heat exchang-er can sometimes be sufficiently effective.

NOTE!Under no circumstances should hydrochloricacid be used with Stainless steel plates.Water of more than 300 ppm Cl may not beused for the preparation of cleaning solu-tions.

It is very important that carrying bars andsupport columns in aluminium are protectedagainst chemicals.

1

23

7 Maintenance

47

Cleaning

Biological growth – slime

• Bacteria

• Nematodes

• Protozoa




High pressure hose.

Chemical cleaning using alkaline cleaningagents:

• Sodium hydroxide• Sodium carbonate• Cleaning effect can be considerably in-

creased by the addition of small quantitiesof hypochlorite or agents for the formationof complexes and surfactants.

Concentration max 4%.Temperature max 80°C.

NOTE!Under no circumstances should hydrochloricacid be used with Stainless steel plates. Water of more than 300 ppm Cl may not beused for the preparation of cleaning solutions.

It is very important that carrying bars and sup-port columns in aluminium are protectedagainst chemicals.

1

23

7 Maintenance

48

Cleaning

Incrustation – scaling

• Calcium carbonate

• Calcium sulphate

• Silicates




High pressure hose.

Chemical cleaning on opened unit by using:

• Nitric acid• Sulfamic acid• Citric acid• Phosphoric acid• Complexing agents (EDTA, NTA)• Sodium polyphosphates


NOTE!Under no circumstances should hydrochloricacid be used with Stainless steel plates.Water of more than 300 ppm Cl may not beused for the preparation of cleaning solutions.


1

23

7 Maintenance

49

Cleaning

Sediment

• Corrosion products

• Metal oxides

• Silt

• Alumina

• Diatomic organisms and their excrement ofvarious colours.




High pressure hose.

Chemical cleaning on opened unit by using:

• Nitric acid• Sulfamic acid• Citric acid• Phosphoric acid• Complexing agents (EDTA, NTA)• Sodium polyphosphates


NOTE!Under no circumstances should hydrochloricacid be used with Stainless steel plates.Water of more than 300 ppm Cl may not beused for the preparation of cleaning solutions.


1

23

7Maintenance

50

Cleaning

Oil residues, asphalt and fats

• Oil residues

• Asphalt

• Fats


Hydrocarbon–based deposits may be removedby using a soft brush and a PARAFFINIC orNAPHTA–BASED solvent (e.g. KEROSINE).

NOTE!Gaskets in natural, butyl and EPDM rubberswell in these media.

Contact time should be limited to 0.5 hour.

The following solvents should not be used:

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

• Esters (e.g. Ethylacetate, Butylacetate)

• Halogenated hydrocarbons (e.g. Chloro-thene, Carbon tetrachloride, Freons)

• Aromatics (e.g. Benzene, Toluene)

Dry with a cloth or rinse with water.

1

2

NOTE!Separate gluing instructions will be deliveredtogether with the glue

7 Maintenance

51

Regasketing

Alfa Laval has two types of glue – GC11 andGC8 for repairs and exchange of gaskets inplates. A special glue, is recommended for vi-ton and silicone gaskets.

GC11

• A two–component, cold curing epoxy gluewhich gives a strong joint for higher temperatures.

• Future removal of gaskets usually requiresheating or freezing of the joint.

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

GC8

• A single–component rubber–based solventadhesive.

• Is normally used for repair work in an un-cured condition.

• Can be used for operating temperaturesbelow 95°C.

• For operating temperatures above 95°Cand oil coolers/heaters, the glued jointsshould be cured at 120°C for one hour.

• Future removal of the gasket can usually becarried out without heating of the cementjoint.

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

Alfa Laval regasketing service

In addition to supplying gaskets for your plateheat exchangers, we are able to provide aSpecialised Regasket Service to fulfil yourservice requirements quickly and efficiently.

Our regasketing service includes a liquid nitro-gen debonding process with chemical clea-ning, crack detection and regasketing using aspecial epoxy/phenolic resin adhesive.

This regasketing process requires specialoven curing of the cement to ensure the

strongest possible bond strength betweenplate and gasket, similar to the process usedduring manufacture.This is one reason whyour service is guaranteed.

In most cases our regasketing service has pro-ved more economical and much faster whencompared with on–site regasketing methods.

For further details please contact your localAlfa Laval Representative.

7Maintenance

52

Regasketing

The Clip–on gasket a glue–free gasket system

The Clip–on gasket in the gasketgroove.

The Clip–on gasket is attached to the plate bytwo gasket prongs which slip under the edgeof the plate to hold the gasket securely inalignment in the gasket groove.

The prongs are situated at regular intervalsaround the periphery of the plate.

When the plate heat exchanger is then as-sembled and tightened, the gasket provides atight seal around the plate.

NOTE!Before closing of the apparatus: Check thatthe two gasket prongs are in correct position.

53

Fault detection

Leakage between plate pack and frame

Action Correction

Mark with a felt tip marker or similar the areawere the leakage seems to be, and open theheat exchanger.

1 Investigate the gasket condition of theend plate and the connection if applica-ble, look for dislocation, foreign objects,scars and other damage to the gasketsurfaces.

1 • Relocate the gasket.• Remove foreign matter.• Replace damaged gasket.• Replace connection lining if applicable.

2 Check the surface of the pressure platefor unevenness, foreign objects stickingto it, etc., that might spoil the joint be-tween the gasket and the adjacent sur-face.

2 Remove anything disturbing the joint be-tween gasket and pressure plate surface.

3 Check the plate itself for cracks or holes. 3 A perforated end plate must be replaced.

8

Fault detection8

54

Leakage between flange and frame

Action Correction

1 Disconnect the flange, and look for misa-lignment between flange and connection,dislocation or damaged gasket, foreignobjects on the surface of the gasket or theflange.

1 • Rearrange the pipe in order to eliminate stress and to correct align-

ment.• Relocate gasket.• Replace damaged gasket.• Replace connection lining if applicable.• Remove foreign matter from flange and

gasket.• Reassemble, taking care to avoid

misalignment.

Fault detection 8

55

Leakage between plates to the outside

NOTE!On a Plate Heat Exchanger specially de-signed for high temperature duties, extremeand sudden temperature drops may some-times cause a temporary leakage. A typicalexample is a sudden shutting–off of the hotmedium flow. The heat exchanger will nor-mally seal again, as soon as the tempera-tures of the apparatus have stabilized.

Action Correction

Mark the leakage area with a felt tip markeron the two plates next to the leakage, checkand note the length of the plate pack betwe-en inside frame plate and inside pressureplate, and then open the heat exchanger.

1 Check for loose, dislocated or damagedgasket.

1 • Relocate gasket.• Recement loose gasket.• Replace damaged gasket.

2 Check for plate damage in the area, andalso check plate pack length againstdrawing to see if possible plate or gasketdamage could be caused by over–tigh-tening of the plate pack, or the leakage it-self simply be caused by insufficient tight-ening.

2 A damaged plate must in most cases be tak-en out for repair or replacement. If it is a reg-ular plate with 4holes: take the damagedplate and the 4–hole plate just in front or justbehind it out of the plate pack. The heat ex-changer can now be reassembled and putback in service PROVIDED THE PLATEPACK IS TIGHTENED TO A NEW MEA-SUREMENT, WHICH IS EQUAL TO THEONE ON THE DRAWING, REDUCED BYTWO TIMES THE SPACE REQUIRED PERPLATE.The small reduction of the heat transfer areais normally of no importance, at least not fora short period of time.

• Insufficient tightening must be corrected– see the drawing.

Fault detection8

56

Action Correction

3 Check hanger recess at both plate endsfor deformations, which could cause mis-alignment between the plates.

3 Damaged hanger recesses must be re-paired if possible, or the plate replaced. Fortemporary arrangement with reduced num-ber of plates – see paragraph 2 above.

4 Make sure that the plates are hangingcorrectly as A–B–A– (see SECTION 4).

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

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

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

Fault detection 8

57

Mixing of media

Action Correction

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

1 Relocate piping to correct connections.

2 Open the lower connection on one side,raise pressure on the other side and bylooking into the open connection try to de-tect any liquid from the pressurized sideleaking in, and if so approximately howfar into the plate pack the leakage is lo-cated.If no leakage is detected, the reason forthe mixing of media must be sought else-where. (See paragraph 5).

3 If a leakage was detected, note the posi-tion of the leakage along the plate packand then open the plate heat exchanger.

4 Before starting on the plates themselves,check that the corner areas between thering and the field gaskets are clear, thatthe leakage slots are open. This ensuresthat any leakage is out of the plate heatexchanger and is to atmosphere. There-fore no pressure can build up to force themedia across the gasket sealing off theother liquid.

4 All deposits or material which can block thefree exit from the area must be removed. Ifthe leak channels of the gasket have beendestroyed, they must be reopened with asuitable tool, or the gasket replaced.

5 If it has not been possible to locate theleakage as described in paragraph 2above, it will be necessary to check eachsingle plate for possible perforations, us-ing any of the following methods:

– put a strong light behind the plate andwatch for light coming through fine holes or cracks

– use a magnifying glass to check suspect area

– use a chemical penetrant, after havingcleaned the plates well.

5 Plates with holes are generally speaking de-stroyed and to be replaced. For temporarysolution with reduced number of plates, see”LEAKAGE between plates to the outside”.

Fault detection8

58

Pressur e drop problems

Pressure drop has increased.

Action Correction

Check that all valves are open including nonreturn valves.

Measure the pressure just before and justafter the heat exchanger, and the flow rate.For viscous media a membrane manometerwith a diameter of at least 30 millimetersshould be used. Measure or estimate theflow rate if possible. A bucket and a watchshowing seconds may be sufficient for smallflow rates. For larger flow rates, some typeof flowmeter is required.

Compare the pressure drop observed withthe one specified for the actual flow rate.(See data print out).

1 If the pressure drop is higher than speci-fied, the temperature program shouldalso be checked:

1 See next paragraph.

1.1 If the thermometer readings correspondto those specified, the heat transfer sur-face is probably clean enough, but theinlet to the heat exchanger may beclogged by some objects.

1.1 Open the apparatus and take out whateveris clogging the passage, or use the back–flush system if there is one to rinse out thecloggings.

1.2 If the thermometer readings are NOTcorresponding to the specified, heattransfer is obviously dropping belowspecifications, because of deposits onthe heat transfer surface, which at thesame time also increase the pressuredrop, since the passage becomes nar-rower.

1.2 If a ”cleaning–in–place system” is avail-able, follow the instruction and use it towash out the deposits. If not, open the ap-paratus and clean the plates.

2 If the pressure drop is corresponding tothe specifications, there is no need forany action.

3 If the pressure drop is lower than speci-fied, the pump capacity is too small orthe observation is wrong.

3 See pump instruction manual.

Fault detection 8

59

Heat transfer problems

The heat transfer capacity is dropping.

Action Correction

Measure temperatures at in– and outletsand – also flow rates – on both media, if pos-sible. At least on one of the media, both tem-peratures and the flow rate must be mea-sured.Check to see if the transferred amount ofheat energy corresponds to the specifica-tions.

If the heat transfer capacity of the appara-tus has dropped below specified values,the heat transfer surface, must becleaned. Either use the ”cleaning–in–place” arrangement provided or open theheat exchanger for visual inspection andmanual cleaning.

If great precision is important, it will be nec-essary to use laboratory thermometers withan accuracy of 0.1 degree Celsius, and alsoto use the best equipment available for flowmeasurement.

60

Supplementary parts

Instrument ring

An instrument ring is sometimes provided tofacilitate the location of, for instance, an instru-ment, a connection for remote monitoring or adrain, next to the heat exchanger rather thanon the piping.

The ring is clamped between the frame orpressure plate and the flange of the pipe. Itrequires longer studs around the connection.

The instrument ring has two nipples pointingradially, with 90 degrees between them. Thelining may be metallic (A) or made of an elas-tomer (B).

An elastomer lining can be replaced with aspare part, while in case of a metallic lining,the whole instrument ring will have to be re-placed.

9

Supplementary parts9

61

The partition plate – for special cases only

If for instance the thermal programme requiresthat at least one of the media is lead in morethan one group through the plate package,there will be heat transfer plates with fewerthan 4 holes.

In order to prevent the thin metal collapsingunder the differential pressure, unpunched cor-ners on larger plates require extra strong sup-port, while the smaller plates are sufficientlystrong as pressed.

The extra support is provided by a partitionplate – approximately the size of a channelplate – made of about 15 millimeters (5/8¨)thick carbon steel, solid at the corners in needof support, and with lined holes at those wherea free passage is required.

The partition plate is suspended from the car-rying bar. Where partition plates are required,there will be one at every turning point in amulti–grouped plate package.

NOTE!

Protection sheets

Depending on the nature of your process orcircumstances related to it, you may be re-sponsible under the law or other regulationsfor adequate protective measures at yourplant.Alfa Laval provides protection sheets for allof our Plate heat exchangers, for the preven-tion of possible harmful effects causes by asudden leakage from the plate package.

62

Spare parts

Identification and ordering of spare parts

As the next sheet in this manual you will find alisting of spare parts for this type of plate heatexchanger. It includes a complete listing ofparts that can be used to build any size or ver-sion of it. Therefore, for some items you willfind a number of options. As an example, car-rying bars are available in various lengths, butin your apparatus only one length is used.

Also, several illustrations show you what thevarious parts look like, and to each partshown, a reference number has been as-signed. These reference numbers are alsorepresented in the second column from the leftin the spare parts listing, and in a chronolog-ical order.

To identify the ORDERING NUMBER, proceed as follows:

Find the illustration of the part for which youneed a replacement and read its referencenumber.

Find this number in the second column of thelisting, and if more than one option is offered,select the line with the one representing yourcase.

Note the long number in the extreme righthand column, which is then your ORDERINGNUMBER for the spare part.

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