Edited by Stephen J. Mraz

Plate exchangers from Alfa Laval, a company based in Sweden (www.alfalaval.com), use corrugated plates which provide the greatest surface area for heat transfer. The number of plates can be adjusted to meet the application, as can the plate material. The corrugations also ensure maximum turbulence for liquids passing through, further increasing heat transfer. The plates are gasketed, welded together, or both, depending on the liquids or gases passing through and whether there’s a need for separating the plates in the future. (Welded plates can handle temperatures to 650°F, and pressures to 625 psig.) The plates are then compressed in a rigid frame to create a series of parallel flow channels. One fluid (or gas), the one being heated for example, travels in odd-numbered channels, the other fluid (or gas) in even-numbered channels.