Although the term"clack" is nowadays used to describe any sort of non return valve, its origins are in the 18th Century tin and lead mines of Cornwall (England.) Most mines tended to flood and enormous beam engines were erected to pump them out. The pump "rod" was actually wood bound with steel straps and typically had a movement of about 6 feet. At the bottom of the rod was a piston, which was little more than a planked platform which fitted the bottom of the shaft. It was a fitted with a trapdoor which lifted as the rod descended, to allow water through, and which closed with a loud "CLACK" as the rod lifted, carrying water with it.
Mike