止回阀

[ noun ]
a simple valve with a hinge on one side; allows fluid to flow in only one direction
<noun.artifact>

Clack \Clack\, n. [Cf. F. claque a slap or smack, MHG. klac
crack, W. clec crack, gossip. See {Clack}, v. t.]
1. A sharp, abrupt noise, or succession of noises, made by
striking an object.

2. Anything that causes a clacking noise, as the clapper of a
mill, or a clack valve.

3. Continual or importunate talk; prattle; prating.

Whose chief intent is to vaunt his spiritual clack.
--South.

{Clack box} (Mach.), the box or chamber in which a clack
valve works.

{Clack dish}, a dish with a movable lid, formerly carried by
beggars, who clacked the lid to attract notice. --Shak.

{Clack door} (Mining), removable cover of the opening through
which access is had to a pump valve.

{Clack valve} (Mach.), a valve; esp. one hinged at one edge,
which, when raised from its seat, falls with a clacking
sound.