Spiral Heat Exchangers – “The Problem Solver” A fully welded heat exchanger for tough process duties In Alfa Laval since the 1930s In total over 40 000 units sold in a variety of industries The largest of our welded products with a yearly sale of about 800 units 40 000 m2 in total 9/2003

Spiral Function Counter-current spiral flow One fluid from centre to periphery The other from periphery to center Co-current flow by reversing one of the sides Channel spacing is flexible between 1/4 to 1” “U” value 2-3 times that of a shell and tube Cover gasket Channel closure Channel closure by bending and welding one edge. Cover gasket seals on each side (prevent by-pass) 9/2003

Spiral - the “self-cleaning” HE Used for tough process fluids Sewage sludge PVC slurries Fermentation broth Heating of Mineral slurries Pulp and Paper Self-cleaning effect with Horizontal mounting Single channel Any deposit will increase the velocity locally and scrub it away Easy access for mechanical cleaning by removing the covers 9/2003

Spiral - deep vacuum condenser Spirals can be fitted as condensers directly on top of columns Able to handle deep vacuum (<6 psia) and large volumes with minimal pressure drop Connecting flange bolted directly to column Substantially lower installation and pumping costs than large S&T mounted on the ground Click on picture to run 9/2003

Spiral - deep vacuum condenser Bona Kemi, Malmö, Sweden Two spiral reflux condensers mounted in series on top of a polymerisation reactor. They perform the same duty as the S&T in the background Norsk Hydro, Bergen, Norway Spiral top condenser installed on the stripper in the cold liquid absorption system that recovers crude oil vaporising during the loading of tankers 9/2003

Spiral - slurry steam heaters Process fluid Process fluid Condensate Inerts Slurry in the horizontal single channel in spiral flow to achieve the self cleaning effect Steam in cross and spiral flow Örtofta sugar factory, Eslöv, Sweden. Two spirals perform as steam heaters of pre-limed sugar juice. In operation without problems since 1978 9/2003

Stud Welding 9/2003

Spiral - winding of the body The heat transfer is made by winding a plate sheet in a mandrill The sheet has spot-welded studs to ensure the channel spacing Studs Mandrill 9/2003

Spiral Channel Welding 9/2003

Channel Closure Each spiral channel welded closed - no intermixing ACW - Alternate Channel Welded is standard Flange or Bar closure 9/2003