GB799060A - Improvements in or relating to steam generators - Google Patents

Abstract

799,060. Water-tube steam boilers; regulating superheat temperature. VORKAUF, H. June 27, 1956 [June 29, 1955], No. 19896/56. Classes 123(2) and 123(3) In a water-tube steam boiler the steam generating tubes 4 lining the furnace front and rear walls discharge into an intermediate header 2 whence tubes 6, 5 lead to the steam and water spaces respectively of the boiler drum 1. A tube coil 3 is disposed in the header 2 and is connected between superheater sections 14, 19. The amount of superheated steam flowing through the coil 3 and thereby attemperated by indirect contact with the steam-water mixture in the header, is controlled by a by-pass valve 21 adjustment of which enables the final steam temperature to be regulated. The valve 21 may be replaced, as shown in Fig. 4, by a rotary valve 28 mounted in the cover of the header 2. In a modification, Fig. 5, the riser tubes 4 discharge into a header 32 which is connected to the drum 1 by a pipe 5 and to an upper header 31 containing the coil 3 by a short vertical pipe. The header 31 is connected to the steam space of the drum 1 by a pipe 6. At lower loads the pipe 5 conducts all of the steam-water mixture to the drum 1 and there is substantially no superheat attemperation. At higher loads, the tendency for the superheat temperature to rise is automatically counteracted by the increased carry-over of water into the header 31. Valves may also be fitted in the pipes 5 to give direct control of the water flow through the header 31.