EG-GRV Butterfly valves - Seat Design Options
EG-GRV offers a wide variety of seat design options which are cost-effective and provide solutions to your service requirements. The Double Offset disc construction minimizes the friction between seat & disc allowing longer seat life even under frequent valve opera-tions. Seats are available in both rigid & flexible construction to suit specific requirements.
The seats are held rigidly by the seat retainer which is inserted within the body per API 609 design requirements. This construction allows use of Gasket conforming to ASME B16.20 Standard and eliminates the possibility of joint leakage from body to atmosphere.
Flexible PTFE Seat
Virgin PTFE seat having a flexi-lip provides bubble-tight shut-off in both directions and suits a wide range of applications. Maximum working Temperature 260°C.
► Flow from seat retainer side
The lip-shaped PTFE Seat moves axially in the direction of flow with the assistance of media pressure. Due to the spherical structure of the disc, as the disc moves more into the seat, the tightness between seat and disc increases with increasing in line pressure. Excessive movement of the seat is limited by the flexible lip which contacts the bot-tom of the groove in the insert ring.
► Flow from shaft side
With the media pressure acting on the disc, it tries to move towards the seat which is supported by the seat retainer. Seat does not move giving simple leak tight seal.
Flexible Metal Seat
Most suitable for high consistency fluids having suspended hard particles, for erosive services, for high temperature services >200°C to 550°C.
Die pressed stainless steel seats with inbuilt flexible properties give Class IV leakage with minimal torque requirements.
Fire Safe Design
The fireproof valve seat is specially designed for urgent shut-down of the system in case of fire. The fireproof valve seat is made of a metal seat ring with a built-in PTFE tape on top that acts as an primary sealing material. In the case if the PTFE is de-stroyed, the secondary metal seat provides effective shut-off.
The Fireproof seat is also ideal for operations of critical important or severe service applications. The wafer sphere butterfly valves combined with fireproof seats have been tested and also ap-proved in accordance with API 607 (4th Edition) and BS 6755 Part II.
