Valve
VALVE (Lat. valna, a leaf of a double or folding door, allied to where, to roll, as of a door on its hinges) , a term applied to many mechanical appliances, devices or natural features, which control, by opening and shutting, the flow of air,. liquids, vapour, gas, etc., through a passage, tube, pipe or other vessel.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)
