An experimental study on the stability of a direct spring loaded poppet relief valve

This paper presents detailed experimental results on the static and dynamic behaviour of a hydraulic pressure relief valve with poppet valve body, with a special emphasis on the parameters influencing the valve instability. The first part of the paper presents the static measurements; sonic velocity in the hydraulic hose, discharge coefficient and fluid flow forces. The results are compared to the data found in the literature and a reasonable agreement was found. The second part presents dynamic measurements of valve chatter. While varying the feed flow rate, pressure and displacement time histories were recorded for a wide range of set pressure. It is shown that the spectra of both signals have similar frequency content, moreover, the frequency of chatter is fairly constant for a wide parameter range, both in terms of flow rate and set pressure. The regimes of qualitatively different motion forms (stable operation, free, impacting and chaotic oscillations) are shown in the flow rate–set pressure parameter plane.