Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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
F22D1/16—Feed-water heaters, i.e. economisers or like preheaters with water tubes arranged otherwise than in the boiler furnace, fire tubes, or flue ways
F22D1/18—Feed-water heaters, i.e. economisers or like preheaters with water tubes arranged otherwise than in the boiler furnace, fire tubes, or flue ways and heated indirectly