Rapid seal abrasion is inherent in the designs of most ball and gate valves. The double block-and-bleed (DBB) General Valve Twin Seal™ plug valve reduces this constant wear by using two seating slips mounted independently on a tapered plug by dovetails, which mechanically retract from the seating surface prior to rotating. This design provides a bubble-tight verifiable dual seal without seal abrasion.

The wide range of applications includes

• pipeline pumping stations and terminals
• refinery bulk loading terminals
• aviation and marine fueling systems
• crude oil and refined products metering and measurement systems
• pig launcher and receiver systems
• other specialty applications in industrial process plants
• renewable fuels and ammonia service.

• Frictionless operation reduces wear on the slip seals and extends seal life. 
• In addition to inline serviceability, the valve enables repairs from above or below.
• It provides bidirectional sealing and double block-and-bleed capability.

• The resilient seal is fully compressed into the slip seal groove, enabling secondary metal-to-metal seating between the slip and body.
• Mechanical sealing capability enhances performance.
• Slip seal bonding is done in house.
• Multiple elastomer options covering many different service conditions are available.
• Differential thermal relief (DTR)—an external thermal relief system is provided to relieve excess body pressure.
• Stem packing is low-emissions certified per API 622 and API 624.