This new automatic valve performs multiple functions in a piping system, including pressure relief, backpressure control, pump bypass and anti-siphon protection. The lug-mounted Series RVDT uses an adjustable, non-wetted spring to control backpressure in a piping system. The set point is adjustable, and once the set pressure is reached, the valve begins to open. All wetted materials are thermoplastic; the metal spring is isolated from the process fluid by a PTFE diaphragm. Pressures can be set from 5 to 150 psi. — Plast-O-Matic Valves, Cedar Grove, N.J.