Patent ID: 8596343

Claim:
A plate heat exchanger comprising a plurality of heat exchanger plates, which are formed from a metal sheet and are provided beside each other, a first end plate provided beside an outermost one of the heat exchanger plates and a second end plate beside another outermost heat exchanger plate, wherein the end plates and the heat exchanger plates are permanently joined to each other by a braze material to form a plate package having first plate interspaces and second plate interspaces, wherein each heat exchanger plate has a pattern forming a heat transfer area and a plurality of porthole areas, each porthole area surrounding a respective porthole defined by a porthole edge, wherein the plate heat exchanger comprises a plurality of flat elements joined to the plate package and having a bottom surface turned towards the plate package, and wherein at least one of the flat elements comprises: (i) a hole possessing an inner surface; and (ii) an annular protrusion extending from the bottom surface and tightly abutting one of the porthole areas of at least one of the outermost heat exchanger plates, the annular protrusion possessing an inner surface offset from the inner surface of the hole.