Abstract: A plate for a plate heat exchanger, the said plate including a principal heat exchange zone, a pattern of corrugations in the heat exchange zone, the said pattern of corrugations being adapted to cross and abut with a corresponding pattern of corrugations on a plate of a similar type to provide interplate support and turbulence in liquid flowing in a flow space formed by two said plates, in which the corrugations are locally increased in stiffness adjacent the intended points of abutment with the corrugations of an adjacent plate by varying the cross-section to increase the curvature at these locations.