Automatic Recirculation Valve Centrifugal Pump Protection Scenarios 
Centrifugal pumps transform mechanical energy into pressure energy by means of centrifugal force resulting from impeller rotation acting on the fluid within the pump. The pump requires a minimum liquid flow in order to avoid overheating. If a predefined minimum flow is not maintained, the pump can be permanently damaged. A number of different pump protection scenarios are reviewed below.

  • NON RETURN SCENARIO The pump has no back-flow prevention and therefore product will flow back through it once it has stopped. A non return valve (NRV) is therefore usually placed after the outlet of the pump. A reservoir is used to take the pumps output when there is no process demand.
  • CONTINUOUS FLOW SCENARIO A manual bypass or leakage path can be added to allow the required minimum flow back to the pump inlet. This system is simple and effective, but is in constant operation and therefore is inefficient and costly (energy costs).
  • CONTROL VALVE SCENARIO This comprehensive control valve solution is highly effective. In this scenario, a flow control valve is connected to a flow meter and allows the main line flow to be metered. As main line flow decreases the control valve opens to allow the correct minimum flow required. However, it is a highly capital intensive solution that requires flow metering equipment, control and non return valves. No reservoir is required.
  • ARV SOLUTION The previous approach stands and falls with the integrity of the control system and its associated cost. A safer system is to combine the non return valve, the bypass valve and the control valve into an interconnected unit, the so called "automatic recirculation valve". This valve closes when there is no flow, automatically opening the bypass line, which is sized for minimum flow. When the main line takes flow but less than minimum, the bypass line and the main line are both partially open.
ZDL Series Automatic Recirculation Control Valve automatic recirculation valve

 ZDL Series

  • Multi-orifice cage bypass, low noise, suitable for middle and low-pressure conditions.
  • Forged steel body, material: carbon steel or Stainless steel, etc.
  • Non-return valve function is standard, Maximum pressure differential up to 6 MPa.
  • With venturi port main flow check valve structure, be applicable for complicated working conditions.
  • Pressure CL150# - 600#, size1’’ - 20’’.
  • Manual bypass operation is optional.

Modern industrial equipment and Technology require centrifugal pumps to basically work under variable flow conditions.
The automatic recirculation valve (ARC valve) is a multifunctional valve whose main purpose is to ensure that the predetermined minimum flow through the centrifugal pump is always ensured. This is important because centrifugal pumps will overheat and cavitation, and will be permanently damaged if idling.


  • Automatic pump recirculation valve is driven by its own medium, minimum flow protection device of centrifugal pump
  • Casting steel, Forged steel valve body
  • Pipe connection: flange
  • Completely mechanical structure, relying on its own medium to control the valve, energy-saving, and low cost
  • The main circuit has a check valve function
  • With flow sensor function
  • The bypass is a multi-stage eddy current decompression structure, which is resistant to cavitation and erosion
  • Leakage level: ANSI V
  • DN25~DN250, PN6.4~32MPa, Class 300 ~ 2500LB

Three protection ways for pump

  • Continuous circulating system
Continuous Circulating System

The minimum requirements of the continuous circulation system pump have nothing to do with the discharge of the process flow change system. After setting the minimum flow rate, it flows directly back to the storage tank through the orifice. Although continuous minimum flow circulation can well protect the pump, the pump must provide greater power output to ensure the system process flow and circulation flow, which will cause additional energy waste.

  • Control circulating system

The control circulation system is composed of a check valve, a flow meter, a minimum flow control valve, and a control circulation system. The control circulation system can provide minimum flow protection. When the process flow is greater than the minimum flow of the pump, the loop is closed and no extra Of energy loss. However, the system is complex, and the control components, purchase, installation, and maintenance costs are relatively high.


  • Automatic recirculation control valve
Automatic Recirculation Control Valve

The automatic circulation valve is equipped with a check valve, a flow sensor, a bypass control valve, and a combination of multi-stage pressure reduction. It does not require power, control systems, and wiring, and is essential for safety. It occupies a small space, minimizes the possibility of high-speed fluid failure, and reduces installation and maintenance costs. It is the first way to protect the pump in modern industrial processes.