US PATENT SUBCLASS 122 / 422
.~ Furnace gases and steam

Current as of: June, 1999
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122 /   HD   LIQUID HEATERS AND VAPORIZERS

412  DF  FEED HEATERS {17}
422.~ Furnace gases and steam

DEFINITION

Classification: 122/422

(under subclass 412) Feed water heaters heated by furnace gases and steam.

SEE OR SEARCH THIS CLASS, SUBCLASS:

403, 425, 432, and 434, for special types of heaters of this nature.