Rotary globe valves help customers meet environmental emissions standards
April 13, 2009
Featuring a specially developed Emissions Free (EF) Seal and many other innovative design characteristics, the valve reduces equipment emissions that can occur at the valve shaft sealing, or packing, particularly after long-term operation. In control valve construction, a delicate balance must be maintained between a tight seal that prevents potentially hazardous emissions and excessive friction between the seal and the valve stem. High friction can affect a valve’s ability to provide the desired control accuracy, which can pose a costly hazard. It can also wear the packing material over time causing leakage and increasing maintenance costs and downtime. Standard on most of the manufacturer’s rotary valves, the EF Seal® is efficiently engineered with few components for ideal sealing functionality. It combines a double O-ring sealed packing follower with low-friction TFE-based packing materials for reliable, long-term service that complies with low-emissions standards. Additionally, the small-range rotary motion of the valve shaft provides many benefits such as preventing contaminants from entering the packing system and causing damage. By rotating in one place, the motion also protects the stem from atmospheric exposure that can accelerate corrosion. Another standard feature of the valve is an integrated extension bonnet that enables the standard TFE packing material to withstand its full temperature range — up to 750°F (400°C).