Hot liquid generator with condensation and installation incorporating this generator

In an installation incorporating a hot liquid generator with steam condensation including a pair of spaced parallel metal sheets spirally wound with spaced turns about a vertical central axis to define hollow spiral wall means;

• a pair of continuous planar end closure members cooperating with opposite ends of said spiral wall means to define a first spiral passage between successive spaced turns of the wall means and a central combustion chamber communicating with said first spiral passage, said sheets being sealed together at their upper and lower ends to define a second spiral passage, and said first and second spiral passages extending continuously between said end closure members, the outer portion of said second passage being adapted for connection with a fluid inlet and the inner portion of said second passage being adapted for connection with a fluid outlet;
• burner means including a plurality of burner elements axially arranged within said combustion chamber for heating said chamber along the vertical dimension thereof;
• blower means connected with the outer portion of said first passage for drawing combustion gases from said combustion chamber through said first spiral passage;
• and means for removing condensed steam from said first spiral passage, the improvement wherein said installation comprises
• (a) suction pump means connected with the inner portion of said second passage for circulating a liquid through said second passage from the fluid inlet to the fluid outlet, said liquid being heated by heat exchange from said combustion gases through said spiral wall means;
• (b) a spacing between successive turns of said spiral wall means which decreases in the direction from the inner portion toward the outer portion of said spiral wall;
• and
• (c) the surfaces of said spiral wall means defining said first passage containing a plurality of local deformations evenly distributed thereon.