Waste heat boiler

Claim 1

Heat exchange apparatus for high temperature gases comprising an upright shell including a top and bottom closure, an upright liquid tube disposed within the shell in radially spaced relation to the shell and defining therewith a vertically elongated annular cooling space, a plurality of concentrically arranged helically wound cooling pipe sections surrounding the liquid tube and disposed in the annular cooling space for a high temperature gas, the cooling pipe sections having gas inlet means communicating therewith disposed near the bottom of the shell, means for supplying coolant disposed near the bottom of the shell, said helically wound gas cooling pipe sections at their upper ends being transformed into substantially straight pipe members disposed between the helical pipe sections and the liquid tube, which pipe members extend to and are connected near the bottom of the shell with gas outlet means, and means defining a plurality of coolant recirculation channels located, respectively, in the spaces between said helical pipe sections, said pipe members and said upright liquid tube.