The Automatic RecirculationValve (ARV) is known to be a multifunction valve whose main purpose is to ensure that the centrifugal pump always maintains a predetermined minimum flow rate. This is important because centrifugal pumps have excessive heating and cavitation and can be permanently destroyed.
The pump and the automatic recirculation valve automatically protect the centrifugal pump during low load operation. If the load on the pump is lower than the preset flow, the valve disc moves to the seat and the bypass port opens the bypass flow path. Therefore, the minimum flow rate of the pump can be reached and maintained.
Application of the automatic recirculation valve
A common application is a pump for treating hot water from the boiler feed water or cooling water, and the pump can dry due to partial evaporation of water. Even if the flow from the main valve to the boiler is completely interrupted, the minimum flow is always maintained.
Another application is to protect high performance pumps when starting. In this case, the pipes and fittings are used in parallel standby. The pump recirculation valve allows replacement without damaging the valve.
Centrifugal forcesinvolve in ARV
Due to the rotation of the wheel acting on the fluid in the pump, the centrifugal pump converts mechanical energy into pressure energy by centrifugal force. To prevent overheating, the pump requires the least amount of fluid. If the specified minimum flow rate is not reached, the pump may be permanently damaged. The following describes several different pump protection schemes.
- The RETURN SCENARIO pump does not prevent backflow and allows the product to flow back after shutdown. Therefore, a non-return valve (NRV) is usually placed behind the pump outlet. This container is used to recover the performance of the pump without processing the request.
- Constant Flow Scenario: You can add a manual bypass or leakage path and return the required minimum flow to the pump inlet. Although this system is simple and efficient, it is inefficient and expensive (energy costs) because it continues to work.
- Control Valve Scenario: This complete control valve solution is very effective. In this case, the flow control valve is connected to the flow meter and the flow of the main pipe can be measured. As the flow rate of the main line decreases, the control valve opens to allow the required minimum flow rate. However, this is a very expensive solution that requires flow meters, control valves and check valves. The tank is not required.
- Previous methods for ARV solutions included control of system integrity and associated costs. A safer system consists of combining check valves, bypass valves and control valves with interconnects called “automatic return valves”. The valve closes when there is no flow and automatically opens the bypass line. When the main line travels but is less than the minimum value, both the bypass line and the main line are partially open.
The advantages of automatic reciculation valve replacement
- Unique design
- Merge function and bypass function
- Original CV computer system
- Lightning protection minimum
- External work is not necessary
- 3 Compatible and high voltage changes available