This paper describes a theoretical and experimental investigation of the impedance characteristics of a cartridge relief valve, which showed high-frequency instability under certain conditions.
Impedance was measured and modelled up to about 4000Hz, and the theoretical model showed good correlation with measurements. Acoustic resonance in the internal chamber is shown to have a very important effect. It is also shown that the spring cannot adequately be modelled by a simple lumped parameter stiffness, and wave effects in the spring become important at high frequencies.
Pressure relief valve, Cartridge valve, Hydraulic impedance, stability