Swagelok”s RHPS Series PRV model proportional relief valves are designed to provide proportional venting of over-pressures for piping systems up to one inch. End connections include NPT female, BSPP female, and BSPP male in sizes 1/4″, 1/2″, 3/4″, and one inch. Available Swagelok threaded adapters convert from BSPP to NPT to allow for easy product installation. Valve operation is smooth, opening gradually and reseating accurately in proportion to the increase and decrease in pressure over the set opening pressure. The PRV’s balanced valve design is unaffected by system back pressure up to 50 percent of the valve’s set pressure. PRV proportional relief valves feature 316L stainless steel construction of the body, trim and spring housing. Fluorocarbon or nitrile seats and seals are available. Available set pressure ranges are 145 PSIG to 580 PSIG (10 bar to 40 bar), 580 PSIG to 1160 PSIG (40 bar to 80 bar), 1160 PSIG to 2170 PSIG (80 bar to 150 bar), 2170 PSIG to 4060 PSIG (150 bar to 280 bar), and 4060 PSIG to 5800 PSIG (280 bar to 400 bar). Depending on the body size selected, flow coefficients (Cv) range from 0.49 to 4.36. All valves are factory-tested, set, and secured with a lock-wire to the pressure range desired. Each valve is tested for specified reseating and shipped with a test certificate. Operating temperature range is -4 F to 176 F (-20 C to 80 C).