Troubleshooting and Repair of Flow Control Valves

The flow control valve is used to control the flow of liquid in the hydraulic system, so as to control the movement speed of the actuator. Flow valves include throttle valve, speed control valve, overflow throttle valve, diverter collector valve and single steady flow valve, etc.

Common faults of flow control valve
The characteristic of the flow control valve is to control the flow of oil by changing the size of the orifice (throttle gap) under a certain pressure difference, and to ensure smooth operation. This type of valve generally has a higher failure rate in the low-speed and small-flow adjustment section, because the low-speed section has a small orifice, is sensitive to the cleanliness of the oil, and has strict requirements on the internal structure and base sealing. And the speed adjustment is required to be stable. The common faults of flow control valve mainly include flow regulation failure, unstable flow and too large internal leakage. The main reason is that the radial clamping of the spool and the failure of the adjusting device, the oil is not clean, the installation is improper, the tightening of the screws is uneven or the valve body is deformed by excessive tightening, which may cause the radial clamping of the spool and the adjustment failure. . Loose locking device, blocked orifice and reverse connection of oil inlet and outlet may cause unstable production flow. The spool valve sealed by the gap wears too much, which increases the internal leakage and also causes the flow to be unstable.

Repair of flow control valve
According to the failure phenomenon of the flow control valve, after identifying the cause of the failure, repair it. Check the geometric accuracy of the spool and sleeve. If the gap is too small, grinding and trimming should be carried out to avoid jamming. If the gap is too large, brush plating technology can be used to repair the valve core. If the valve core and seat are not well sealed, they should be ground. The spring is deformed or broken and should be corrected or replaced.