I was translating for a member of our local car club a specification for an inlet manifold for a Jaguar racing engine. The part was in the US and the spec. referred to a non-reversing ratchet. To me a ratchet is a gear with an asymmetric spring loaded pawl that only allows the gear to turn one way. What has that got to do with inlet manifolds? I translated that as 'cliquet' which is the French for my kind of ratchet and my friend was equally baffled.
So I searched the Net and found a US pump company that referred to a non return valve on their pump outlet, that preserved the prime when the pump stopped, as a non-reversing ratchet. It was the the ball and spring variety.
To me that is in French a "clapet", which my friend understood and we concluded that it was a non return valve in the manifold to prevent blowback as these highly tuned engines can do on the overrun.
Is this usage peculiarly American or have I missed out on by identifying the part as a non-return valve?