For steam service
This type PRV is similar to the internally piloted piston-operated valve in that a pilot and main valve are utilized. However, double diaphragms replace the piston. This increased diaphragm area can open a larger main valve, allowing a greater capacity per line size than the internally piloted piston-operated valve. In addition, the diaphragms are more sensitive to pressure changes, which results in accuracy of +/-1%. This greater accuracy is due to the positioning of the sensing line downstream, where there is less turbulence. This valve also offers the flexibility to use different types of pilot valves (i.e., pressure, temperature, air-loaded, solenoid or combination).