SUREFLO AUTOMATIC
RECIRCULATION VALVE

The SureFlo Automatic Recirculation Valve protects centrifugal pumps during low load operation and is available in sizes up to 16 inches and pressure class to ASME 2500#. The SureFlo AR Valve encompasses all of the hardware required in a conventional bypass system in a single housing.

Operation

Main Flow Only - Bypass closed (Figure 1)

When the process associated with the pump is in the normal operating condition, the main line is open.

The pressure created by the media (through the pump) is sufficient to compress the spring in the check valve disc part of the AR valve and lift itt from it's seat to the fully open position.

As the connected disc stem rises, the bypass exit in the in the stem funnel is closed. The bypass flow is therefore inversely proportional to the main pump flow. When the check valve is fully opened, the bypass is fully closed.

Combined Flow (Figure 2)

As the flow requested by the process is reduced the pressure on the disc spring is lowered and the disc moves towards its seat. The check valve part of the automatic recirculation valve moves first to a partially open position. In this position, there is partial flow to the main line outlet and a minimum flow to the bypass is maintained.

Bypass Only - No main Flow (Figure 3))

When no product is required by the process the valve disk returns to the seated position. There is insufficient flow to compress the spring and allow the disc to rise.

In this position, the curved part of the hollow stem is now flush with the entrance to the bypass funnel. A predefined minimum flow can now move from the pump through the bypass section of the AR valve and be recirculated to the front end of the pump. The pump is thereby protected from overheating or cavitation.