The Si 9 Series safety valves ensure reliable overpressure protection in steam boilers, superheaters, and process steam systems. Designed to ASME I, III, and VIII standards, they feature a fixed overpressure and blowdown mechanism with no adjustment rings required, ensuring consistent performance. A full nozzle design and stellited disc and seat provide durability and tight shutoff, while a special disc spring design supports high pressures and large valve sizes. Available in sizes from NPS 1.5 to NPS 12 and handling pressures up to 330 bar g, the Si 9 Series is ideal for high-performance steam applications.

Key features

Sizes: NPS 1.5 to NPS 12

Set pressures: 3–330 bar g

Temp: up to 650°C

No adjustment rings needed

Full nozzle design

Stellited disc and seat

25% backpressure allowed