(under subclass 272) Apparatus which makes some provision for preventing freezing of water in the riser or around the valve, by providing for its removal from the hydrant, by arrangement of the connection to the water main or by means provided inside the flow path.
SEE OR SEARCH THIS CLASS, SUBCLASS:
59+, for freeze condition responsive safety systems, especially subclass 61 for low temperature responsive cut offs, and 62 for low temperature responsive drains.
68.11+, for system control by frangible means.
107, for systems where a waste or drain valve opens in response to stoppage of flow.
272, for arrangements for getting water out of frozen hydrants. 281, for prevention of freezing by providing an expansible chamber for draining water from the riser and retaining it below the frost line for later use.
297, for hydrant casings with heater.
338, for system installations providing for circulation of air from below to above ground for freeze protection purposes.
SEE OR SEARCH CLASS
138, Pipes and Tubular Conduits,
32+, for thawing and freeze protection for pipes and tubular conduits.
