Multi-pass heat exchanger circuit

A plate and fin heat exchanger in which a flowing fluid is compelled to make plural passes through the heat exchanger at least at one level thereof, including

• (a) superposing plates at said one level;
• (b) marginal plate spacer means defining an internal flow area between said plates having an inlet and an outlet;
• (c) at least one divider member positioning intermediately of said spacer means to have an inner end terminating within said flow area and defining with said spacer means and with one another a circuitous flow path between said inlet and said outlet including plural passes paralleling said divider member, said flow path further including a portion of transverse extent around the inner end of said divider member;
• (d) and a single continuous layer of a secondary heat transfer material occupying the entirety of said flow area including said flow passes and said portion of transverse extent of said flow path and providing fin-like corrugations approximately parallel to said divider member and extending beyond the said inner end of said divider member to and through said portion of transverse extent of said flow path, said layer being slotted to accommodate said divider member;
• (e) and corrugations of said layer being slit at least in the location of said flow path portion of transverse extent to provide for fluid flow transversely of said corrugations in said portion.