Mechanical Dimple
A mechanical dimple jacket is a sheet of metal which has a uniform array of depressions or dimples pressed into the metal. Each of the dimples typically has a center hole which is fillet welded to the base metal. The dimpled sheet is formed to the contour of the shell or head, and the edges are welded around the circumference of the jacket. The thickness and pitch of the dimple layout determine the pressure rating. Depending on the application, the flow path of the media can be routed for optimal efficiency, or to clear manways, fittings or other discontinuities. Mechanical dimpled jackets typically give high pressure ratings, have a low to moderate pressure drop, and are moderate in cost.
Inflated RSW Dimple
An inflated RSW jacket is manufactured by resistance spot welding an array of spots on a thin sheet of metal to the thicker base metal. The edges are welded solid and all other forming operations are performed. The jacket is inflated, under high pressure, until the thin jacket material deforms to form a pattern of dimples. Like mechanical dimples, the flow path can be altered as needed. Inflated RSW dimple jackets have moderate pressure ratings, a high to moderate pressure drop, and low cost.
