Patent ID: 8028746

Claim:
A heat exchanger for a gas boiler for producing hot water; the heat exchanger ( 4 ) comprising a casing ( 13 ) extending along a first axis (A 1 ) and through which combustion fumes flow; a tube ( 11 ) along which water flows, and which is housed inside said casing ( 13 ) and coils about the first axis (A 1 ) to form a helix ( 16 ) comprising a succession of turns ( 17 ); and deflecting means ( 12 ) for directing the fumes between successive turns ( 17 ); said tube ( 11 ) comprising at least a first and a second fins ( 23 , 24 ) extending along the length of said tube ( 11 ) and facing one another; said heat exchanger being characterized in that said first and second fin ( 23 , 24 ) are tangent to said tube ( 11 ).