safety valve
relief valve
escape valve
escape cock
escape **

This caused the relief valve for the pressurizer to stick open.

This often means that the relief valve will not re-seat once the set pressure is reached.

For these systems often so called "differential" relief valves are used.

It was only about ten years too late, Kelly estimated, looking up from his notes at the relief valve.

Why, for example, is America the "relief valve" for all the political and economic problems of the world?

Sometimes you have to replace a little that has escaped through relief valves.

He'll have a relief valve like a tight end or a running back.

Without the relief valve to the north I don't know what would have happened to Mexico.

It is also felt to offer a humorous relief valve from the university's rigorous academic program.

He didn't want to blow out the relief valve.