Abstract: A plate heat exchanger having a first set of plate assemblies arranged alternately with a second set of plate assemblies in a stack. Each plate assembly has first and second plates which are spaced apart to define a flow path for fluid. The flow paths of the first set of plate assemblies extend in crossing relationship to the flow paths of the second set of plate assemblies. Because of the double wall design of the plate assemblies, any leakage will be vented before being able to corrode through to the other fluid. The plate assemblies have enlarged inlet and outlet openings for fluid to reduce pressure drop and pumping cost. One plate of each plate assembly has a first set of dimples to establish the space between plates and produce turbulence for good heat transfer, and a second set of dimples of reduced height to produce less pressure drop but still produce turbulence.

Abstract: A plate heat exchanger having a stack of plates with spaces between the plates defining passages for hot and cold fluids. The ends of the plates define inlet and outlet openings for the fluid passages. The openings are enlarged by bending the end of one of the two plates for each flow path away from the corresponding end of the other of these plates and welding it to an adjacent plate. Preferably the ends of the plates are triangular, or V-shaped, to lengthen the openings along each edge of the V.