Water-Tube Boiler

a steam boiler with a heating sur-face of steel tubes whose exterior surfaces are exposed to the gaseous end products of fuel combustion (flue gases). Water and a steam-and-water mixture circulate within the tubes, which are connected by drums and headers to form a single system. Vertical water-tube boilers with a steam-generating capacity of 2.5 to 640 tons an hour and single-pass boilers with a steam-generating capacity of 250 to 2,500 tons an hour are manufactured in the USSR for use in various types of boiler plants. The production of horizontal water-tube boilers has been discontinued.