The Si 4 Series high-flow safety valves provide efficient overpressure protection for pressure vessels, heat exchangers, and piping systems. Designed for vapours, gases, and liquids, these state-of-the-art valves feature a cost-effective semi-nozzle body and press-fitted seat bushing for long-term reliability. The modular design ensures easy maintenance with standardised spare parts, while a safe spring unloading system allows disassembly without affecting set pressure. Built from carbon steel (1.0619) and stainless steel (1.4408), the Si 4 Series is available in DN 20 to DN 200 sizes with set pressures from 0.1 to 40 bar g, ensuring optimal safety performance.

Key features

Set pressures: 0.1 to 40 bar g

Sizes: DN 20 to DN 200

Carbon & stainless steel

Semi-nozzle body design

Unloaded spring for safe disassembly

Modular design