(under the class definition) Subject matter relating to closures for openings in furnace-walls.
SEE OR SEARCH THIS CLASS, SUBCLASS:
172, for doors in front structure.
192, for devices which feed air or steam to the furnace for a limited time.
SEE OR SEARCH CLASS
48, Gas: Heating and Illuminating,
124, for lids for retorts. 49, Movable or Removable Closures, appropriate subclasses for closures of the type provided for and see the search notes in section IV of Class 49 for the loci of closures in other classes.
122, Liquid Heaters and Vaporizers,
498, for doors with water circulation connected with the boiler.
