sanitary plate heat exchangers working principle of a plate heat exchanger

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Sanitary Plate Heat Exchangers

Working Principle of a Plate Heat Exchanger

© Alfa Laval Slide 2 www.alfalaval.com

PHE - Main ComponentsCarrying bar

Pressureplate

Plate packTightening bolts

Frame plate

© Alfa Laval Slide 3 www.alfalaval.com

PHE - Dismantling

Click on animation to play again

© Alfa Laval Slide 4 www.alfalaval.com

Plate Heat Exchanger

360˚ turn

© Alfa Laval Slide 5 www.alfalaval.com

Plate Heat Exchanger

inside

© Alfa Laval Slide 6 www.alfalaval.com

Cold in

Hot out

Hot in

Cold out

Plate Pack - Example Single Pass

End

Pla

te I

I

End

Pla

te I

Cha

nnel

pla

tes

Only 2 plates that do not transfer heat - the end plates

© Alfa Laval Slide 7 www.alfalaval.com

Pass/Channel: Hot Side 2 x 4

Cold Side 2 x 4

Cold in

Hot outHot in

Cold out

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Plate Pack – Example Multipass

© Alfa Laval Slide 8 www.alfalaval.com

In the Dairy

• Milk pasteurization

• Cream pasteurization

• Cultured milk treatment

• UHT

• Cheese milk heat treatment

• Ice cream mix heat treatment

Applications

© Alfa Laval Slide 9 www.alfalaval.com

Pasteurization

ApplicationsIP

© Alfa Laval Slide 10 www.alfalaval.com

Frame - purposeFrame - purpose

• Holds the plates together

• Supports the plates (load / pressure)

• Base for connections (inlet / outlet for media)

© Alfa Laval Slide 11 www.alfalaval.com

Frame - TypesFrame - Types

• Industrial types (mild steel, painted):

FM, FG, FD

Only used for utility (water heaters/coolers)

• Hygienic types (stainless steel):

Base, FMC, FHC, FRM, FRH, FRD, RM

Normally used in the Food industry

© Alfa Laval Slide 12 www.alfalaval.com

• Unique 5-point alignment system

– Provides exact positioning of the plates horizontally and vertically

– Ensures good sealing throughout the plate pack

Carrying bar

Guiding bar

Plate

Frame - > M15 and FrontLine™

© Alfa Laval Slide 13 www.alfalaval.com

FrontLine™FrontLine™

• Solid stainless steel frame and pressure plates

• Cleaner since there is no risk of cracks in cladding allowing dirt and bacteria build-up

• More durable since there is no internal mild steel structure that can corrode

© Alfa Laval Slide 14 www.alfalaval.com

• Stainless steel bolts with ball bearing washers

• Reduces service time

FrontLine™FrontLine™

© Alfa Laval Slide 15 www.alfalaval.com

• Bolt-in corners at connection plates

• Easy to modify for new duties and applications

FrontLine™FrontLine™

© Alfa Laval Slide 16 www.alfalaval.com

Other Options• 3A polished fittings

• Connections in Titanium

• High legs

• Protection sheets

• Stainless steel bolt covers

FrontLine™FrontLine™

© Alfa Laval Slide 17 www.alfalaval.com

Hygienic Frame - CHygienic Frame - Connection Plate

• Connection plates are used in multi–section units when one or more fluid must enter or leave the PHE at a location other than the frame or pressure plate.

• Available as standard for types with hygienic frames – Front 10, Front 8, Front 6, Clip 3, M15, M10, M6, TL10B

© Alfa Laval Slide 18 www.alfalaval.com

Plates - Plates - Purpose

• Create channels for the liquids (corrugation).

• Create turbulence for the flow

• Provides the heat transfer from one media to the other media.

© Alfa Laval Slide 19 www.alfalaval.com

• Plate pattern (L , M and H )

• Pressing depth

• Clip and M plates

B plates

• Physical length and width of plate

• Increase the number of passes

The Channel Plate Construction

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© Alfa Laval Slide 20 www.alfalaval.com

PlatesPlates

Distribution area

Inlet / outlet Media 1

Heat transfer area

Distribution area

Inlet / outlet Media 1Inlet / outlet Media 2

Inlet / outlet Media 2

Fully supported gasket groove

© Alfa Laval Slide 21 www.alfalaval.com

Plate - Distribution Area

• Chocolate pattern

– Distributes flow evenly over the plate

– Same P for distance A and B

– Uses a minimum of P for distribution

– Gives more P for efficient heat transfer

– Avoids dead spots in the far corner

A

B

© Alfa Laval Slide 22 www.alfalaval.com

Corner Guidance

• First alignment made by the carrying & guiding bar

• Corner guidance locks the plates in position and fine-tunes the alignment

© Alfa Laval Slide 23 www.alfalaval.com

Plate - Corrugation and Channels

L: Low theta H: High theta

• We have two plate corrugations (L and H)

L + L = L channels L + H = M channels H + H = H channels

• These form three different channels (L, M and H)

• We choose between L, M and H channels

• Tailor-made for the specific duty

© Alfa Laval Slide 24 www.alfalaval.com

Plate - corrugation and channels

Advantages

• Efficient heat transfer

• High wall shear stress

• Variable thermal length

• Strong construction

Benefits

• Increased heat recovery

• Low fouling

• Optimal design

• Insensitive to vibration

Low turbulence& pressure drop

L + L = L channels

Medium turbulence& pressure drop

L + H = M channels

High turbulence & pressure drop

H + H = H channels

© Alfa Laval Slide 25 www.alfalaval.com

The Plate Corrugation hastwo Functions:

Mechanical – to make the plate rigid and provide interplate support points.

Flow dynamic – to promote interplate fluid turbulence for high efficiency.

Compact

© Alfa Laval Slide 26 www.alfalaval.com

• Herring bone

• Contact points

– Mechanical Strength

• Flow pattern

– Cork screw

– High turbulence

Plate Pattern

© Alfa Laval Slide 27 www.alfalaval.com

The Front Standard Plate

• High and Low theta plates

• Optimize the design for both thermal and product considerations

© Alfa Laval Slide 28 www.alfalaval.com

The Front Standard Plate

• Deeper pressing depthDeeper pressing depth

• Ability to handle small Ability to handle small particulatesparticulates

© Alfa Laval Slide 29 www.alfalaval.com

The Front Standard Plate • Wide corrugationsWide corrugations

• Longer run times at same rate Longer run times at same rate of foulingof fouling

Other unit

Clip plate

© Alfa Laval Slide 30 www.alfalaval.com

The Front Standard Plate

• Five point alignment systemFive point alignment system

• Ensures plate and gasket are Ensures plate and gasket are aligned during take-upaligned during take-up

• Reinforced for frequent Reinforced for frequent opening and closingopening and closing

© Alfa Laval Slide 31 www.alfalaval.com

The Front Standard Plate

• Long & narrow geometryLong & narrow geometry

• Even flow & heat transfer Even flow & heat transfer across plate surfaceacross plate surface

• Low CIP flow ratesLow CIP flow rates

© Alfa Laval Slide 32 www.alfalaval.com

The Front Standard Plate

• Flow distribution areaFlow distribution area

• No “dead spots” for better No “dead spots” for better hygienehygiene

• Promotes even flow across Promotes even flow across plate surfaceplate surface

© Alfa Laval Slide 33 www.alfalaval.com

The Front Standard Plate

• Smaller port holes, tubing Smaller port holes, tubing dimensionsdimensions

• Lower CIP flow rates, better Lower CIP flow rates, better hygienehygiene

© Alfa Laval Slide 34 www.alfalaval.com

The Front Standard Plate

• Bright annealed finish

• Easier to clean

• Easier to inspect

• Higher corrosion resistance

© Alfa Laval Slide 35 www.alfalaval.com

Sanitary PHE Plate DesignSanitary PHE Plate DesignSanitary PHE Plate DesignSanitary PHE Plate Design

• Plate geometry (long & narrow)Plate geometry (long & narrow)

• Port holesPort holes

• Distribution areaDistribution area

• Stagnant areasStagnant areas

• Pressing depth and corrugationPressing depth and corrugation

• Plate surfacePlate surface

•……to eliminate any risk for to eliminate any risk for infection in pasteurisersinfection in pasteurisers

• Plate geometry (long & narrow)Plate geometry (long & narrow)

• Port holesPort holes

• Distribution areaDistribution area

• Stagnant areasStagnant areas

• Pressing depth and corrugationPressing depth and corrugation

• Plate surfacePlate surface

•……to eliminate any risk for to eliminate any risk for infection in pasteurisersinfection in pasteurisers

Front standard plate

Other plate

© Alfa Laval Slide 36 www.alfalaval.com

Plate Pack Assembly

• Channel Plate

• End Plate II(gasket against frame)

• End plate I(metal against frame)

• Turn Plate

• Transition Plate

• Partition Plate

• Connection PlateEnd plate II

End plate I

© Alfa Laval Slide 37 www.alfalaval.com

Plate Pack - Channel Plates

• Channel Plates are the heat transfer plates

• They dominate the plate pack

• Most frequently with 4 holes punched

• Alternating A / B (turned 180 degrees)

© Alfa Laval Slide 38 www.alfalaval.com

Plate Pack - End Plate I• In single pass,

– Stops fluid at the end of the plate pack

– Last plate at carbon steel pressure plate

– No port holes are punched

Sin

gle

pass

Exa

mpl

e,

Mul

ti pa

ss• In multi-pass,

– Stops one fluid as it reaches the end

– Allows other to flow into the plate pack

– 2nd last plate in the plate pack (transition plate behind it)

– Hole combination as per pass arrangement

• Normal gasket as on channel plates

• Usually in 0.6 mm with high-theta pattern

© Alfa Laval Slide 39 www.alfalaval.com

Plate Pack - Turning Plate

• Used in multi-pass

• 1, 2 or 3 port can be un-punched

• Change the flow direction of one or both fluids in between the passes

• Normal channel plate gasket

© Alfa Laval Slide 40 www.alfalaval.com

Number of plates depends on:

• Flow rates

• Permitted pressure drops

• Temperature program

• Size & design of plates

• Heat recovery

• Material & thickness of plates

• Physical properties

The Construction

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© Alfa Laval Slide 41 www.alfalaval.com

• Plates are totally uniform

• Uniform metal-to-metal contacts points

• Stronger plates that can handle

– High pressure

– High differential pressure

– Vibrations

Single Step Pressing

Plate Pressing

© Alfa Laval Slide 42 www.alfalaval.com

Plate - Pressing Depth

Performance

Pressing depth

• pressure drop• heat recovery• compact design

• gentle product treatment• special products• clogging problems

Thermal Product

• Alfa Laval has a range of pressing depths from 1.5 mm to 11 mm for optimal solution to any duty

There is no good and no bad pressing depth. Just different ones to fit various duties

© Alfa Laval Slide 43 www.alfalaval.com

Plate - Parallel vs. Diagonal Flow

Parallel flow advantages

• One plate & one gasket

– Identical plates in plate pack

– Rotated 180º to achieve both sides

• Less spares required

• Fully supported diagonal

– Higher design pressure or thinner plate material

• No crossing of nozzles

180º

© Alfa Laval Slide 44 www.alfalaval.com

Plate - Materials• Standard materials and thicknesses

• AISI 304 (stainless steel)

- Usually 0.4 or 0.5 mm thick

- Cheapest possible solution

• AISI 316 (stainless steel) - 0.5 and 0.6 mm thick

- Some with thicker plates (high-pressure applications)

• 254 SMO (high-alloy stainless steel)

- Usually in 0.6 mm to allow stock-keeping

• Titanium - 0.5 and 0.6 mm thick

- Some with thicker plates (high-pressure applications)

- Some with 0.4 mm (low-pressure applications)

• Alloy C-276 (Nickel alloy)

- Usually in 0.6 mm to allow stock-keeping

100%

115%

250%

300%

600%

RelativePrice

© Alfa Laval Slide 45 www.alfalaval.com

Gaskets - PurposeGaskets - Purpose

• The purpose of the gaskets is to seal between the channel plates and between plates and the frame parts (connecting plate).

• Are the only wear part (the ageing of rubber).

© Alfa Laval Slide 46 www.alfalaval.com

The Front Standard Plate

• Glueless gasket

• Gasket & plate work together as a system to replace adhesives

• Less downtime, plates can be re-gasketed in frame

© Alfa Laval Slide 47 www.alfalaval.com

The Front Standard Plate

• Deep gasket groove

• Protection of gasket from elements

• Higher pressure ratings

• Ensures gasket remains on plate during opening

© Alfa Laval Slide 48 www.alfalaval.com

The Front Standard Plate

• Thicker Gasket

• Better resistance to thermal, pressure and CIP cycles

• Longer gasket life

© Alfa Laval Slide 49 www.alfalaval.com

The Front Standard Plate

• Twin gasket w/ leak detect ports

• No chance for cross contamination across gaskets at port holes

© Alfa Laval Slide 50 www.alfalaval.com

Gasket - double sealing system

Special venting ports are an integral part of the gasket design to prevent cross contamination

If the gasket fails Leakage is detected on the outside

© Alfa Laval Slide 51 www.alfalaval.com

Gaskets - StandardGaskets - Standard

Nitrile:

• NBRP = (performance) up to 110°C, Food grade

• NBRB = (base) inexpensive, lower temperature, Food grade

• NBRHTF = (high temperature) Food grade

• NBRFF = upgrade of NBRHTF Food grade

Ethylene Propylene rubber:

• EPDMC = clip-on/non-glued. High temperature (non food)

• EPDMF = Food grade (FDA)

• EPDFF = upgrade of EPDMF Food grade (FDA)

(Not resistant to oil and fat)

© Alfa Laval Slide 52 www.alfalaval.com

Gasket - Profile and Groove

Profile

OtherAlfa Laval

Groove

Higher sealing pressure

Risk of leakage.

Full support to gasket

Openings. Risk of gasket blow-out.

The difference is lifetime and reliability

© Alfa Laval Slide 53 www.alfalaval.com

Gasket - Sealing Lifetime

Product

• Gasket material

• Fastening

– Glue or glue-free

– Type of glue

• Gasket geometry

• Gasket groove

• Alignment of plate pack

Duty

• Operating temperature

• Operating pressure

• Media

• Type of operation continuous / cyclic

• Cleaning methods & chemicals

• Opening frequency

Life time!

© Alfa Laval Slide 54 www.alfalaval.com

Gasket - Sealing Lifetime

• Maximum temperature in CAS and product manual (PMP), for example,

– NBR up to 130ºC

– EPDM up to 160ºC

Gives about 1 year lifetime When no chemical attack takes place

• Rule of thumb:

– 10ºC lower than max temperature 2 years lifetime

– 10ºC above the max temperature 6 months lifetime

© Alfa Laval Slide 55 www.alfalaval.com

PMP - Pressure/Temperature

• A P/T graph can be made from data sheet information showing the expected performance of the plate & gasket– The design P/T should be inside the performance area– If P/T is on the line 1 year gasket lifetime– If P/T is outside Cannot guarantee the performance– If the gasket is chemically attacked more aspects to be added

0

5

10

15

20

25

0 50 100 150

Temperature (°C)

Pre

ssu

re (

bar

g)

Performance area

Limited by the max design pressure for the plate

Gasket lifetime limited by the max temperature

Gasket lifetime limited by a combination of pressure and temperature

© Alfa Laval Slide 56 www.alfalaval.com

PMP - Pressure/Temperature

• The data is found in the data sheet

– In the gasket performance table

• T(T) = The maximum allowed operating temperature. Above this temperature the gasket will last less than one year.

• T(P) = Recommended temperature at max pressure. Higher pressure More strain on the gasket We cannot allow the max temperature

– In the plate performance table

• P(P) = Maximum design pressure for the plate.Above this pressure the plate will deform.

• P(T) = Recommended max operating pressure at max operating temperature.

Higher pressure Softer gasket We cannot allow the max pressure

© Alfa Laval Slide 57 www.alfalaval.com

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