Common faults of flow valve and their elimination methods

1. Adjust the flow valve flow without change

(1) Fault phenomenon: The flow rate of the regulating flow valve does not change (the pressure compensation valve operates abnormally).

Cause analysis: ①The spool of the flow valve cannot be moved; ②The fit gap between the valve body and the spool of the flow valve is too small. 

Elimination method: ① Overhaul or replace the flow valve spool; ② Increase the gap between the valve sleeve and the spool.

(2) Fault phenomenon: the flow rate of the regulating flow valve does not change (throttle valve fault).

Cause analysis: ①The throttle port of the throttle valve is blocked; ②The installation position of the throttle valve spool is not suitable; ③The fit clearance of the throttle valve spool is too small.

Elimination method: ① check the hydraulic oil quality; ② reinstall; ③ overhaul and make the fit clearance within a reasonable range. 

2. The movement speed of the actuator is unstable

(1) Fault phenomenon: the movement speed of the actuator is unstable (throttle valve fault).

Cause analysis: ① The external load changes; ② The throttle valve is sometimes open and sometimes blocked.

Elimination method: ① Replace the throttle valve with a speed regulating valve; ② Disassemble and overhaul the throttle valve.

(2) Fault phenomenon: the movement speed of the actuator is unstable (the quality of the hydraulic oil is poor).

Cause analysis:① The throttle valve throttle port is blocked; ② The oil temperature exceeds the reasonable range, and the flow rate of the throttle valve throttle port changes.

Elimination method: ①Remove and overhaul the throttle valve. If the oil quality does not meet the requirements, it should be replaced in time; ②Check the cause and control the hydraulic oil temperature within a reasonable range.

(3) Fault phenomenon: the movement speed of the actuator is unstable (pipeline vibration).

Cause analysis: ①The determined adjustment position is changed due to pipeline vibration; ②There is air in the hydraulic system.

Elimination method: ①After the adjustment position is determined, fix it; ②Exhaust the air in the hydraulic system.

(4) Fault phenomenon: the movement speed of the actuator is unstable (leakage).

Cause analysis: There is leakage in the flow valve, and the leakage is unstable.

Methods for Elimination: Minimize leakage.