Water Check Valves

check valves
(Check valve) A check valve, clack valve, non-return valve or one-way valve is a mechanical device, a valve, which normally allows fluid (liquid or gas) to flow through it in only one direction.
(Check valve) used to provide flow through a pipe in one direction only. When installed between an external filter and the pond, it keeps the dirty water in the filter from flowing back into the pond if power is lost. They are also used to keep an external pump primed if power is lost.
A valve that closes to prevent backward flow of liquid
(Check valve) A device inserted into a moving liquid stream that allows flow of the stream in only one direction; most often used on the inlet and outlet sides of an HPLC pump.

water
binary compound that occurs at room temperature as a clear colorless odorless tasteless liquid; freezes into ice below 0 degrees centigrade and boils above 100 degrees centigrade; widely used as a solvent
A colorless, transparent, odorless, tasteless liquid that forms the seas, lakes, rivers, and rain and is the basis of the fluids of living organisms
supply with water, as with channels or ditches or streams; "Water the fields"
One of the four elements in ancient and medieval philosophy and in astrology (considered essential to the nature of the signs Cancer, Scorpio, and Pisces)
body of water: the part of the earth's surface covered with water (such as a river or lake or ocean); "they invaded our territorial waters"; "they were sitting by the water's edge"
This as supplied to houses or commercial establishments through pipes and taps