Over Pressure Shut Off Valve

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

pressure
The continuous physical force exerted on or against an object by something in contact with it
The force exerted per unit area
a force that compels; "the public brought pressure to bear on the government"
the force applied to a unit area of surface; measured in pascals (SI unit) or in dynes (cgs unit); "the compressed gas exerts an increased pressure"
coerce: to cause to do through pressure or necessity, by physical, moral or intellectual means :"She forced him to take a job in the city"; "He squeezed her for information"
The use of persuasion, influence, or intimidation to make someone do something

valve
A device for controlling the passage of fluid through a pipe or duct, esp. an automatic device allowing movement in one direction only
device in a brass wind instrument for varying the length of the air column to alter the pitch of a tone
control consisting of a mechanical device for controlling the flow of a fluid
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