Two-stage or multi-stage water-level control for steam generators

摘要

In order to achieve, in steam generators with two-stage or multi-stage control of the water level, a simultaneous throughflow of feed water and flue gas in the feed-water preheater, the feed pump is only switched on when the furnace is working, and the highest water level is not reached, or when the lowest water level is reached. Furthermore, the feed-water flow or the furnace capacity is limited in such a manner that the feed-water flow corresponds to a great extent to the quantity of steam generated at the respective furnace capacity. The limitation of the feed-water flow can take place by means of a throttle with bypass lines, which can be connected in a stepped manner, in the feed-water line, by means of a speed control of the feed pump or other means.