a disk-shaped valve turning on an axis along its diameter, serving esp. as a damper in a pipe or as a choke or throttle in a carburetor
- A disk turning on a diametrical axis inside a pipe, used as a throttle valve or damper.
- A valve composed of two semicircular plates hinged on a common spindle, used to permit flow in one direction only.
top: open valve
bottom: closed valve