F22D—PREHEATING, OR ACCUMULATING PREHEATED, FEED-WATER FOR STEAM GENERATION; FEED-WATER SUPPLY FOR STEAM GENERATION; CONTROLLING WATER LEVEL FOR STEAM GENERATION; AUXILIARY DEVICES FOR PROMOTING WATER CIRCULATION WITHIN STEAM BOILERS
F22D1/00—Feed-water heaters, i.e. economisers or like preheaters
F22D1/32—Feed-water heaters, i.e. economisers or like preheaters arranged to be heated by steam, e.g. bled from turbines
Arrangement protecting flue tube against overheating because of water exhaustion with steam pressure actuated electric switch stopping the firing combined with fusing element