T&S BRASS BL-5550-09

VACUUM BREAKER ANTI-SIPHON 3/8 NPT MAL

American National Standard Pipe Thread standards, often called National Pipe Thread ("NPT") standards for short, are U.S. national technical standards for screw threads used on threaded pipes and pipe fittings. They include both tapered and straight thread series for various purposes including rigidity, pressure-tight sealing, or both. The various types are each named with a symbol and a full name; examples of the symbols include NPT, NPS, NPTF, NPSC, and others.

A siphon is any of a wide variety of devices that involve the flow of liquids through tubes. In a narrower sense, the word refers particularly to a tube in an inverted "U" shape, which causes a liquid to flow upward, above the surface of a reservoir, with no pump, but powered by the fall of the liquid as it flows down the tube under the pull of gravity, then discharging at a level lower than the surface of the reservoir from which it came.

A vacuum breaker is an attachment commonly placed on a bibcock valve or toilet or urinalflushvalve, that prevents water from being siphoned backward into the public drinking water system. This prevents contamination should the public drinking water
system's pressure drop.