The Keystone 129 and 139 are resilient seated, heavy duty Butterfly Valves. The Keystone F129 and F139 are designed for use in seawater service in the commercial marine and offshore markets.
Features
Primary stem seal, formed by preloaded contact of disc hub with flatted seat surfaces, completely isolates stem and body from the line media
Secondary stem seal, formed by an engineered interference fit of the stem through the seat, provides additional sealing integrity
Rounded, polished disc edge provides full 360 degree concentric seating, minimum flow restriction, lower seating and unseating torques and maximum seat life
Superior, one-piece thru-shaft design provides high-strength and positive disc control. Shaft ends are standardized for operator interchangeability
Self-locking disc screws allow quick and easy disassembly and provide a positive connection.
Self-adjusting, bi-directional stem seal is suitable for full industrial vacuum and pressure, preventing external contamination of the stem area
Heavy-duty, corrosion-resistant top bushing absorbs actuator side thrust loads
Replaceable, metal-reinforced seat, completely encapsulated by rubber, isolates the stem and body from the media and eliminates seat distortion due to high vacuum or turbulence
Each Valve is factory tested to 110 percent of specified pressure rating assures drop-tight shut-off
Cast-in top plate is an integral part of the body and is standardized to allow direct mounting of all Keystone Actuators.
