Closed center system

  The closed center system means that when the reversing valve is in the middle position, the oil path is closed, the hydraulic oil does not return directly to the oil tank, and the hydraulic pump only provides the flow required for the internal leakage of the system. When the spool is reversed, the hydraulic oil flows to the actuator, thus avoiding the bypass return oil loss inherent in the open center system. The advantage of the closed center system is that the speed of each actuator is only related to the valve core displacement, independent of the load and the flow rate of the hydraulic pump, and there is no interference between the multiple actuators.