Patent ID: 8180207

Claim:
A heat exchanger comprising: a case; and a substantially pillar heating element, said heating element being accommodated in said case such that a cylindrical space is formed between an outer peripheral surface of said heating element and an inner peripheral surface of said case, wherein said cylindrical space is closed at one end and another end, said case having a fluid inlet through which a fluid flows into a vicinity of said one end of said cylindrical space and a fluid outlet through which a fluid flows out of a vicinity of said other end of said cylindrical space, said heat exchanger further comprising a flow velocity converter that changes a flow velocity of the fluid within said cylindrical space, said flow velocity converter comprising a spiral member for forming a spiral flow path within said cylindrical space, wherein said spiral member is configured such that a clearance is formed between the inner peripheral surface of said case and at least part of an outer periphery of said spiral member and/or between the outer peripheral surface of said heating element and an inner periphery of said spiral member, and that the fluid flowing into said cylindrical space from said fluid inlet flows out of said fluid outlet through said spiral flow path and said clearance.