Dished Ends

Dished ends, also known as dished heads or end caps, are hemispherical or elliptical components that form the closure at the ends of cylindrical pressure vessels like evaporator bodies. They are engineered to distribute stress evenly under internal pressure, preventing flat surfaces that would require excessive thickness. Common types include torispherical (with a knuckle radius), elliptical (2:1 ratio), and hemispherical designs, each offering different strength-to-weight ratios and manufacturing complexities. They are critical for maintaining vessel integrity, facilitating cleaning, and allowing for nozzle attachments.

Dished ends work by converting internal pressure loads into tensile stresses distributed across their curved surface, following the principle that a curved structure is stronger than a flat plate under pressure. The curvature reduces stress concentrations, allowing thinner material usage while maintaining safety. In evaporators, they help contain steam or process fluids, with the shape promoting efficient fluid flow and minimizing dead zones. The knuckle region (in torispherical designs) transitions stress smoothly from the cylindrical shell to the crown.