Abstract: Apparatus for forming corrugated sheet material includes coacting rolls (10,11) by which material having corrugations with crests and intervening flanks is formed. The crests are closed up to one another by a first pair of rollers (22) which run at relatively high speed followed by a second pair of rollers (27) which run at a relatively low speed. The rollers engage the crests or the side edges of the material to control the rate of feed of the material between each pair of rollers.The invention finds application in forming corrugated metal sheet for heat exchangers.

Abstract: Apparatus for making corrugated sheet material, primarily intended for use in heat exchangers as secondary heat exchange surfaces, includes a pair of rolls rotatable in opposite directions to draw sheet between the rolls.The rolls are made up of laminae each with the same corrugated profile having teeth circumferentially spaced around the laminae. The teeth of each lamina are spaced from the teeth of adjacent laminae so that the sheet is sheared into interconnected strips each of corrugated form, the corrugations being displaced from one another in the longitudinal direction of the strips.The corrugated material produced by the apparatus has improved heat exchange characteristics by virtue of the presentation to a flow of fluid over the material of a plurality of free edges of the material.