ABSTRACT

The flow-pressure relationship is an important external characteristic of the pilot operated pressure relief valve. Many research efforts have been put on this topic for its significant impact on the overall hydraulic system. Some of the researches focused on the influences of the hydraulic bridge to the main stage, while the others attempted to analyze the influence of difference pressure measurement (direct or indirect) of the system pressure using control theories. In this project, a novel method
has been adopted. The basic idea is to find out the correlation between the pilot flow and the overflow of the main valve, and use this relative function as a criterion to compensate for the force bore on the valve poppet. The flow-pressure curve of the relief valve can be bent upwards(under-compensated), flat, or downwards(over- compensated). The above scheme has been utilized in the manufacture’s product catalogs.