The SIP Automatic Recirculation Valve (AR Valve) protects pumps during minimum flow conditions and is ideal for applications with pressures between 120 and 250 bar in systems with continuous operation, even at load points below the pump minimum flow requirements. Ideally suited for high pressure multi-stage feedwater pumps at Eskom Power Stations.

“Reliable Pump Protection”

Scope

The most relevant application for this valve type is the boiler feed water cycle of combined cycle power plants (CCPP). In these power plants the bfw-pumps operate frequently at minimum flow conditions with pressures of 100–250 bar. The reason is the technical concept of a CCPP – for example gas turbine cooling with bfw – as well as its purpose to cover load peaks or the natural load fluctuation of renewables in the energy grid.

Operating Principle

The bypass of the SIP valve is controlled by a multistage piston providing a near cavitation-free operation at any time thanks to the multistage pressure reduction at all flow rates. The piston also ensures a modulating flow control from 100 %–10 % bypass flow rate. An accelerated shut-off (1–2 sec.) at <10 % opening avoids most wear critical operation range.

Our Valve Repair Centres in Secunda and Durban provide a full valve repair and reconditioning service.

The wear-intensive extreme partial load range is deliberately overridden. The piston seat is separated from the pressure reduction and located at the high-pressure side. Thus, the shut-off function is optimally protected against cavitation attack. Even if cavitation would occur in the last throttle stages, the shut-off function would not be affected leaving the valve fully functional.

Contact one of our technical specialists for a quote today or download the brochure to learn more.