(under the class definition) Apparatus which stop reverse flow of a liquid in a distribution system by preventing or eliminating the vacuum condition which would cause the reverse flow, such as a condition which would start siphoning.
(1) Note. The normal flow in these systems is not of the siphon type.
SEE OR SEARCH THIS CLASS, SUBCLASS:
143, for breakers in flow devices which are intended to act as siphons.
441, for refill pipes which may act as vacuum breakers.
526, for vacuum relief valves, per se.
583+, for distribution systems having plural openings, one of which is a gas vent, and see the search notes to subclasses 583 and 587. SEE OR SEARCH CLASS
251, Valves and Valve Actuation,
34, for reverse flow prevention in choked pressure type servo motors which actuate valves.
399, Electrophotography,
237+, for liquid developer applied to a latent image within an electrophotos:graphic device.
