Heads (Dished Ends)

Dished ends, also known as heads or dished heads, are specialized components used as closures for cylindrical pressure vessels like feedwater tanks. They feature a curved geometry (typically hemispherical, ellipsoidal, or torispherical) that distributes internal pressure more evenly than flat ends, reducing stress concentrations. In industrial applications, they provide structural integrity, facilitate pressure containment, and often include openings for nozzles, manways, or instrumentation.

Dished ends work by converting internal pressure loads into membrane stresses distributed across their curved surface. The geometry (radius of curvature) determines stress distribution: hemispherical heads have uniform stress, ellipsoidal heads balance depth and stress, and torispherical heads offer cost-effective pressure resistance. They seal the vessel ends while allowing for thermal expansion and pressure cycling without failure.