Plate-type heat-exchange apparatus

A plate-type heat-exchange apparatus in which two heat exchanging media flow counter-current, comprising a stack of rectangular plates which, when joined together in pairs, define an element having an internal channel for the flow of one heat-exchanging media and when a second similar element is joined together with the first element, the first and second elements coact to provide a channel therebetween for the other heat-exchanging media, each plate having end parts and a middle part therebetween, the middle part having alternate crests and troughs extending transversely thereof, every other crest of one plate having a plurality of plane surfaces at spaced intervals along said crest providing passageways across said crest leading to the troughs on each side of said crest, the crest on each side of said troughs having a row of spaced outwardly extending projections, every other trough of the other plate having a row of spaced outwardly extending projections, so that when said plates are stacked together to define the element, the plane surfaces of one plate adjoin the crests of the other plate to provide the internal channel with a corrugated shape in longitudinal section and a substantially slotted shape in cross-section, and upon said second similar element being positioned on the first element, the projections of said one plate of the first element adjoin the projections of said other plate to provide the channel therebetween of corrugated shape in longitudinal section and substantially slotted shape in cross-section, a distributing zone at each end part for the heat exchanging media, means providing communication between one distributing zone and one of the channels, and further means providing communication between the other distributing zone and the other channel.