Hydraulic Control Valve is operated hydraulically, designed to move by driving pressure difference beeween upside chamber and downside chamber which are caused by diaphragm or piston in valve. The diaphragm or piston divides the actuator into two distinct pressure chambers, and the control system list are also including disc, cock, tube, spring, needle valve and pilot valve. Whenever the upside diaphragm chamber exceeds to the downside chamber in force（caused by pipeline pressure）,the disc is enforced to close. Otherwise the disc is opened by pressure of downside chamber, pipeline system maintainers are able to operate the valve by driving the pilot valve and setting pressure balance of both pressure chambers, which could make the valve to be used in a wide range of applications.
水力型控制閥主要是藉由隔膜或活塞所形成的壓力室、閥盤、控制管路、針閥、響導閥所建構成的水力動態平衡系統 ，以達到設計之控制目的。 當壓力室所形成之推力大於管線動水對閥盤的推力則閥盤關閉；當壓力室所形成之推力小於管線動水對閥盤的推力則 閥盤開啟；當壓力室所形成之推力等於管線動水對閥盤的推力則閥盤處於平衡的浮動調節狀態，而此平衡位置操作人 員可藉由響導閥設定。