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[example needed] A typical backflow assembly has test cocks and shut-off valves, and must be tested when installed, if relocated or repaired, and also on a periodic basis. [citation needed] In the US, the Environmental Protection Agency (EPA) holds local water suppliers responsible for maintaining a certain amount of purity in potable water ...
An anti-siphon valve is also required here to prevent pressure drops in the water supply line from suctioning water out of the toilet tank (which may contain additives such as "toilet blue" [53]) and contaminating the water system. Anti-siphon valves function as a one-direction check valve. Anti-siphon valves are also used medically.
A recent introduction to the UK has been the Reduced Pressure Zone (RPZ) valve, a form of double check valve where the intervening zone is drained and normally kept empty. [1] If the downstream valve leaks and permits backflow, this will drain out through the vent rather than building up pressure against the upstream valve.
This arrangement prevents any contaminants in the sink from entering into the potable water system by siphonage; this is the simplest form of backflow prevention. A common use of the term "air gap" in domestic plumbing refers to a specialized fixture that provides backflow prevention for an installed dishwasher .
Toward the end of the discharge process, the ballcock responds to the drop in water level and refills the tank. Should the float or valve fail and allow the water level to exceed the fill line, the water will pour into the overflow tube and out to the bowl (in the flapper valve type) or to an outside drain (in the siphon type).
A science fair or engineering fair is an event hosted by a school that offers students the opportunity to experience the practices of science and engineering for themselves. In the United States, the Next Generation Science Standards makes experiencing the practices of science and engineering one of the three pillars of science education.
A siphon spillway uses the difference in height between the intake and the outlet to create the pressure difference required to remove excess water. Siphons require priming to remove air in the bend for them to function, and most siphon spillways are designed to use water to automatically prime the siphon.
Vacuum valve may refer to: Trickle valve, a type of airlock; Vacuum breaker, an anti-siphon valve; Vacuum delay valve, an automobile component; Vacuum tube, an electron tube or thermionic valve; Vacuum interrupter, an electrical device acting similar to a circuit breaker, used in higher voltage applications