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
F22D5/00—Controlling water feed or water level; Automatic water feeding or water-level regulators
F22D5/08—Controlling water feed or water level; Automatic water feeding or water-level regulators with float-actuated valves
F22D5/10—Controlling water feed or water level; Automatic water feeding or water-level regulators with float-actuated valves and with pistons or membranes unitary with the feed inlet valves