Butterfly valves, like ball valves, operate with a 1/4 turn. They are generally used for handling large flows of gases or liquids, including slurries, but should not be used for throttling for extended periods of time. They are also very compact relative to flanged gate and ball valves saving in both space and typically the overall cost of the valve. The butterfly valve controls flow by using a circular disc or vane with its pivot axis at right angles to the direction of flow in the pipe. The butterfly valve is used both for on-off and throttling services