GB240192A - Improvements in and relating to superheaters and the like - Google Patents

Abstract

240,192. Akt.-Ges. Brown, Boveri, et Cie. Sept. 22, 1924, [Convention date]. Combustion products, returning to furnaces.- In superheaters, feed-water heaters, tubular boilers, &c. which have the temperature reduced by returning smoke gases to the furnace, these gases are introduced at the point of lowest pressure in a restricted nozzle through which the furnace gases pass prior to use. As shown applied to a superheater the tubes D are shielded from the direct flame of the furnace A with the travelling grate B by a nozzle-shaped part C built of refractory bricks. Waste gases taken off at H are conveyed by a fan J through a pipe K and forced at a high velocity through jet nozzles L at the throat of the nozzle-shaped part C so that a suction is caused acting on the furnace gases. Soot or dust may be removed through the door M. The superheater tubes D comprise nests of coils in which the steam travels in counterflow to the waste gases, but at high superheat temperatures the steam may travel partly in the same direction as the gases so that the tubes conveying the hottest steam are in the region of the cooler gases. Air is fed to the grate B through an air heater F and a pipe G. The central return pipe K forces the gases to sweep over the tubes D in a uniform manner but when the superheater tubes are differently arranged the return pipe for the gases may be situated outside the setting. To protect the nozzle-shaped part C from the flame, the waste gases may issue through an annular nozzle arranged below it, through the centre of which the furnace gases are drawn. Additional blowers may be provided, and the invention is stated to be applicable also to coal-dust, oil or gas furnaces.