Water Stop Valve

water stop
A water stop or water station on a railroad is a place where trains stop to replenish water. The stopping of the train itself is also referred to as "water stop". The term originates from the times of steam engines, when large amounts of water were essential.
A water stop is a break and a place to break for drinking water in sports events (sports competitions or training) for some types of sports, such as various long distance types of running (e.g., marathon), cycling, etc.
Pausing to lose some water.

valve
device in a brass wind instrument for varying the length of the air column to alter the pitch of a tone
A device for controlling the passage of fluid through a pipe or duct, esp. an automatic device allowing movement in one direction only
A membranous fold in a hollow organ or tubular structure, such as a blood vessel or the digestive tract, that maintains the flow of the contents in one direction by closing in response to any pressure from reverse flow
A cylindrical mechanism in a brass instrument that, when depressed or turned, admits air into different sections of tubing and so extends the range of available notes
a structure in a hollow organ (like the heart) with a flap to insure one-way flow of fluid through it
control consisting of a mechanical device for controlling the flow of a fluid