Self-acting back pressure regulators are simple control valves offering accurate control while being easy to install and maintain. They control the pressure upstream of the valve without requiring pneumatic or electrical control elements.
The RP 116 overflow valve is a pilot-controlled control valve consisting of main valve with position indicator, control unit, pilot valve, pressure gauge, stop valves and connecting pipes. The main valve cone is fitted with a soft seal. This valve which has been specially developed for drinking water applications, features an electrostatically deposited coating on internal and external surfaces and meets the KTW recommendation of the German Ministry for Health.
When the pipeline is depressurised or inlet and outlet pressures are equal, the main valve is kept closed by its spring.
When the inlet pressure rises above the set pressure the control medium flows towards the valve outlet via the open pilot valve. A restrictor in the control unit produces a pressure drop upstream of the diaphragm causing the inlet pressure to overcome the control pressure and spring force and open the main valve.
As soon as the inlet pressure has reached the set pressure, the pilot valve restricts the flow. This causes the pilot pressure to rise and push the main valve cone into a controlling position. When the inlet pressure falls below the set pressure the pilot valve closes. The pilot pressure continues to rise and the main valve also closes.
The pressure difference between inlet pressure and outlet pressure must be at least 0.5 bar!
The control unit contains adjustable restrictors which allow the control characteristics of the pressure reducer to be matched to the system (closing, opening and response speeds).
The overflow valve is completely piped. It does not require any additional pilot lines.
These valves are no shut-off elements ensuring a tight closing of the valve. In accordance with DIN EN 60534-4 and/or ANSI FCI 70-2 they may feature a leakage rate in closed position in compliance with the leakage classes V (soft seal cone = 1.8 x 10-5 x ?p x D* [l/h], *D=seat diameter).