The RHPS series PRV model proportional relief valves provide proportional venting of overpressures for piping systems up to 1-inch size. End connections include NPT female, BSPP female, and BSPP male in sizes 1/4, 1/2, 3/4 and 1 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. Choose fluorocarbon or nitrile seats and seals. Available set pressure ranges are: 145 to 580 psig, 580 to 1160 psig, 1160 to 2170 psig, 2170 to 4060 psig and 4060 to 5800 psig. Depending on body size selected, flow coefficients 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 to 176 degrees F.