Typical Failures of Pilot Relief Valve

With the development of construction machinery hydraulic system towards the direction of medium, high and ultra-high pressure, pilot relief valve is widely used in the oil control pipelines of construction machinery hydraulic systems. In practice, in order to maximize its efficacy and protect the control system, accurate and timely diagnosis and troubleshooting of sanitary relief valve is a key link.

1. Control failure, so that the host doesn’t run
Failure of pilot relief valve will cause the host to stop running. Possible reasons include: the valve core spring of pilot valve is broken; damping hole is blocked; poor sealing of valve opening of pilot valve; the main valve core is stuck. The corresponding solutions are: replacement or adding a flattened pad at the broken place for emergency use; cleaning and dredging; grinding or cutting off the oil pipeline for emergency use; grinding and cleaning.

2. Instable limit pressure
Instable limit pressure of pilot relief valve is demonstrated as lower or higher hydraulic system pressure, weakness of hydraulic actuator or burst of oil tube, pump and valve body.

The causes of this failure include: improper pressure regulation; bending or softening of pilot valve core spring; overly dirty oil or unsmooth flow of the oil. The corresponding solutions are: readjustment; recalibrating, pad-adding or replacement; replacement and cleaning.

Limit pressure instability of pilot relief valve is a gradual failure. It mostly occurs in construction machinery with more motorcycle hour reserve. Limit pressure failure of pilot relief valve is a sudden failure. It mostly occurs in construction machinery with less motorcycle hour reserve. After troubleshooting, we should readjust the pressure of pilot relief valve according to the pressure defined by the system.