ball valve

a valve controlling flow by means of a ball pierced with an opening in one direction and fixed to rotate on a spindle at right angles to the opening.

any valve that checks flow by the seating of a ball.

Origin of ball valve

First recorded in 1830–40

At o is a delivery valve, opening outwards, which is often a ball-valve but sometimes a flap-valve.

Encyclopaedia Britannica, 11th Edition, Volume 14, Slice 1 |Various
The ball-valve is supported by a suspension thread (T) from the roof of the bell (B).

Encyclopaedia Britannica, 11th Edition, Volume 14, Slice 3 |Various
Should the pressure increase, the bell (B) is raised and with it the ball-valve (V).

Encyclopaedia Britannica, 11th Edition, Volume 14, Slice 3 |Various
The communication between the train-pipe and the cylinder is controlled by a ball-valve, one form of which is shown in fig. 2.

Encyclopaedia Britannica, 11th Edition, Volume 4, Slice 4 |Various

When the pressure falls again, the ball-valve is lowered and more gas passes through.

Encyclopaedia Britannica, 11th Edition, Volume 14, Slice 3 |Various

ball valve

a one-way valve consisting of a metal ball with a cylindrical hole fitting into a concave seat over an opening

ball valve

A valve regulated by the position of a free-floating ball that moves in response to fluid or mechanical pressure.