Quarter-turn rotary plug valve with seats reciprocable during operation

摘要

A method and apparatus for controlling fluid flow with a quarter-turn plug valve with seats operated to lift off the sealing surface of the plug prior to plug rotation and to reseat upon completion of plug rotation. One embodiment shown relates to a quarter-turn rotary plug valve having a handle operable through a 90 ° angle and having both upstream and downstream seats which are operated to lift off from the sealing surface of the plug prior to initiation of plug rotation and then reseat upon completion of plug rotation.