Counter-flow heat exchanger with helical tube bundle

Claim 1

In a counter-flow heat exchanger of the type comprising: at least one helical tube bundle arranged in an annular chamber between a core tube and a coaxial tubular shell and connected to a primary inlet and a primary outlet for flow of a primary fluid through said helical tube bundle; a plurality of contiguous helical tubes associated with said bundle and connected in parallel to said primary inlet and said primary outlet, said helical tubes being coiled in a corresponding helical plane with constant pitch around a common longitudinal axis and being closely arrayed without interruption between said core tube and said tubular shell so as to define therewith at least one closed helical channel connected to a secondary inlet and a secondary outlet so as to thereby provide for flow of a secondary fluid through said closed helical channel in countercurrent with the primary fluid flowing through said helical tube bundle, the improvements comprising; said helical tube bundle being equipped with two auxiliary connecting compartments lying within said annular chamber and each consisting of a perforated auxiliary connecting plate arranged perpendicular to said corresponding helical plane and a removable cover sealingly mounted on said auxiliary connecting plate and connected to said primary inlet or outlet; and said auxiliary connecting plate comprising staggered perforations arranged parallel to said corresponding helical plane and offset with respect thereto so that the ends of said contiguous helical tubes are accommodated in corresponding perforations and sealingly secured in said connecting plate without undergoing significant bending with respect to said corresponding helical plane.