GB361028A - Improvements relating to steam generators - Google Patents

Abstract

361,028. Indirectly heated steam boilers. STUBBS, A., 390, Wilbraham Road, Chorlton - cum - Hardy, Manchester. Sept. 6, 1930, No. 26678. [Classes] 123 (ii) and 123 (iii).] Boilers having combined direct and indirect steam generating means of the kind which include surface type evaporators heated by steam and connected to the steam and water drum on both steam and water sides have means for controlling the level in the drum by throttling the steam connection between drum and evaporator and for regulating the rate of feed by the temperature of the outgoing steam. A boiler comprising furnace wall tubes 1, 2 and a drum 4 has an evaporator 9 having its water and steam spaces connected to the drum by pipes 16, 12. A throttle valve 13 at the end of pipe 12 within the drum is operated in accordance with water level by means of a float 15. If the level falls the valve tends to close and increased pressure in the evaporator displaces water therefrom into the drum until equilibrium is maintained. The boiler feed valve 18 is operated through the agency of a thermostat 19 influenced by the outgoing steam temperature. If this becomes excessive water is admitted and rises in the evaporator until the steam passing through the more fully immersed heating element 8 is sufficiently reduced in temperature. The throttle valve may be located within the evaporator.