(under the class definition) Apparatus including structure by which a stream of fluid is directed to sweep across an opening of a heating or combustion chamber to hinder or prevent entry or discharge of gases through the opening.
SEE OR SEARCH CLASS
110, Furnaces,
179, for a solid fuel furnace having a fluid screen for one of its openings.
454, Ventilation,
188+, for a building having a door or window provided with a fluid curtain.
