Patent ID: 6585228
Filing Date: 2003-07-01
Classification: F16K

Abstract:
A valve actuator, comprising:an actuator housing; a bonnet secured to said actuator housing having a stem bore therethrough; a stem positioned within said stem bore of said bonnet, said stem configured for attachment to a valve closure member within a gate valve wherein movement of said stem moves said valve closure member within said gate valve between open and closed positions corresponding to operating and failsafe positions of said gate valve; a biasing module positioned within said actuator housing, connected to said stem and having a biasing member for urging said stem to a failsafe position; a transmission module moving said stem between said failsafe and operating positions, said movement opposed by said biasing member; a power module driving said transmission module; a control module to selectively release said stem from its operating position and allow said biasing member to move said stem to its failsafe position; and, a clutch assembly connected to said transmission module to control the movement of said stem at a preselected, linear rate as said stem is moved by said biasing member to said failsafe position.