The plate and frame heat exchanger is designed to provide maximum efficiency in transferring heat from one liquid to another, or from steam to liquid. The heat exchanger consists of a series of gasketed, embossed metal plates arranged alternately and bolted together between end frames to form channels through which hot and cold media flow. The hot fluid flows on one side of the plate while the cold fluid flows on the other, with the plate itself providing the most effective means to transfer heat from one fluid to the other. Gaskets mounted on the plates seal the channels and provide flow direction. As liquids flow counter-currently through the channels between the plates, the cold liquid becomes warmer and the hot liquid cooler.