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• A fully welded heat A fully welded heat exchanger for tough exchanger for tough process duties process duties

• In Alfa Laval since the In Alfa Laval since the 1930s 1930s

• In total over 40 000 units In total over 40 000 units sold in a variety of sold in a variety of industriesindustries

• The largest of our welded The largest of our welded products with a yearly sale products with a yearly sale of aboutof about– 800 units 800 units – 40 000 m40 000 m22 in total in total

Spiral Heat Exchangers – “The Problem Solver”Spiral Heat Exchangers – “The Problem Solver”

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• Counter-current spiral flowCounter-current spiral flow

– One fluid from centre to peripheryOne fluid from centre to periphery

– The other from periphery to centerThe other from periphery to center

• Co-current flow by reversing Co-current flow by reversing one of the sidesone of the sides

• Channel spacing is flexible between 1/4 to 1”Channel spacing is flexible between 1/4 to 1”

• ““U” value 2-3 times that of a shell and tubeU” value 2-3 times that of a shell and tube

Cover gasket

Channelclosure

• Channel closure by bending and welding Channel closure by bending and welding one edge.one edge.

• Cover gasket seals on each side (prevent Cover gasket seals on each side (prevent by-pass)by-pass)

Spiral Function

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• Used for tough process fluidsUsed for tough process fluids– Sewage sludgeSewage sludge– PVC slurriesPVC slurries– Fermentation brothFermentation broth– Heating of Mineral slurriesHeating of Mineral slurries– Pulp and PaperPulp and Paper

• Self-cleaning effect withSelf-cleaning effect with

– Horizontal mountingHorizontal mounting

– Single channelSingle channel

• Any deposit will increase the Any deposit will increase the velocity locally and scrub it awayvelocity locally and scrub it away

• Easy access for mechanical cleaning Easy access for mechanical cleaning by removing the coversby removing the covers

Spiral - the “self-cleaning” HESpiral - the “self-cleaning” HE

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• Spirals can be fitted as condensers directly on top of columnsSpirals can be fitted as condensers directly on top of columns• Able to handle deep vacuum (<6 psia) and large volumes with minimal pressure dropAble to handle deep vacuum (<6 psia) and large volumes with minimal pressure drop• Connecting flange bolted directly to columnConnecting flange bolted directly to column• Substantially lower installation and pumping costs than large S&T mounted on the groundSubstantially lower installation and pumping costs than large S&T mounted on the ground

Click on picture to run

Spiral - deep vacuum condenserSpiral - deep vacuum condenser

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Norsk Hydro, Bergen, NorwayNorsk Hydro, Bergen, NorwaySpiral top condenser installed on the Spiral top condenser installed on the stripper in the cold liquid absorption stripper in the cold liquid absorption system that recovers crude oil system that recovers crude oil vaporising during the loading of vaporising during the loading of tankerstankers

Bona Kemi, Malmö, SwedenBona Kemi, Malmö, SwedenTwo spiral reflux condensers Two spiral reflux condensers mounted in series on top of a mounted in series on top of a polymerisation reactor. They polymerisation reactor. They perform the same duty as the perform the same duty as the S&T in the backgroundS&T in the background

Spiral - deep vacuum condenserSpiral - deep vacuum condenser

9/2003

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• Slurry in the horizontal Slurry in the horizontal single channel in spiral flow single channel in spiral flow to achieve the self cleaning to achieve the self cleaning effecteffect

• Steam in cross and spiral Steam in cross and spiral flowflow

Steam Process fluid

Processfluid

Condensate

Inerts

• Örtofta sugar factory, Eslöv, Örtofta sugar factory, Eslöv, Sweden. Two spirals Sweden. Two spirals perform as steam heaters of perform as steam heaters of pre-limed sugar juice. In pre-limed sugar juice. In operation without problems operation without problems since 1978since 1978

Spiral - slurry steam heatersSpiral - slurry steam heaters

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Stud WeldingStud Welding

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• The heat transfer is made by winding a plate sheet in a mandrillThe heat transfer is made by winding a plate sheet in a mandrill• The sheet has spot-welded studs to ensure the channel spacingThe sheet has spot-welded studs to ensure the channel spacing

Mandrill

Studs

Spiral - winding of the bodySpiral - winding of the body

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Spiral Channel WeldingSpiral Channel Welding

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Channel ClosureChannel Closure

• Each spiral channel welded closed - no intermixing

• ACW - Alternate Channel Welded is standard

• Flange or Bar closure