Automatic Shut Off Valve

automatic
(of a device or process) Working by itself with little or no direct human control
(of a firearm) Self-loading and able to fire continuously until the ammunition is exhausted or the pressure on the trigger is released
operating with minimal human intervention; independent of external control; "automatic transmission"; "a budget deficit that caused automatic spending cuts"
automatic rifle: light machine gun
(of a motor vehicle or its transmission) Using gears that shift by themselves according to speed and acceleration
automatic pistol: a pistol that will keep firing until the ammunition is gone or the trigger is released

shut off
block off the passage through; "We shut off the valve"
isolate or separate; "She was shut off from the friends"
A device used for stopping a supply or operation
The cessation of flow, supply, or activity
stem the flow of; "shut off the gas when you leave for a vacation"

valve
a structure in a hollow organ (like the heart) with a flap to insure one-way flow of fluid through it
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 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 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
control consisting of a mechanical device for controlling the flow of a fluid