The Series 300 safety valves are conventional spring-loaded relief valves with a balanced metal bellows design. They operate by maintaining a predetermined pressure using a calibrated spring. When the system pressure exceeds the set pressure, the fluid force overcomes the spring force, opening the valve to release the excess pressure. Once the pressure returns to normal, the spring automatically closes the valve.

The balanced metal bellows design (in 316Ti or Inconel) offers exceptional set pressure stability by compensating for the effects of upstream pressure. This technology eliminates the influence of backpressure on valve performance, ensuring precise opening and closing at the predetermined set pressure, even under varying pressure conditions.

The body is made of WCC 1.0619 carbon steel for high mechanical strength. Internals are available in 1.4404 stainless steel, Inconel®, or Monel® depending on the application. The choice depends on the fluid, temperature, and service conditions: 1.4404 stainless steel for most general applications, Inconel for high temperatures and severe corrosive environments, and Monel for marine applications and certain specific chemicals.

The Series 300 safety valves comply with API 520/526 standards for calculations and selection. They are certified to PED 2014/68/EU for pressure equipment and ATEX 2014/34/EU for explosive environments. The long 316L stainless steel nozzle is NACE compliant for enhanced corrosion protection in sulfurous environments.

The sizing must comply with API 520/526 standards and take into account several parameters: the flow rate to be discharged, the set pressure, the permissible overpressure, the backpressure, the temperature, and the nature of the fluid. The range of available orifices is from D to R (6R10 available) with diameters from DN20 to DN150 mm. Correct selection ensures adequate protection while preventing accidental openings or malfunctions.