Visual experimental investigation on the stability of pressure regulating poppet valve

Abstract

The unstable vibration of a poppet valve drastically fluctuates pressure which directly affects the stability, reliability and safety of a hydraulic system. The unstable vibration of the poppet and cavitation is studied using visual experiments. Experimental results show that for a poppet valve, an orifice at the front of the valve cavity, the compressibility of oil in the sensitive cavity will lead poppet to unstable vibrations. For poppet valve without orifice, the instable vibration appears as three states: impact valve seat, transition (impact or non-impact valve seat occurs randomly) and does not impact valve seat. When poppet impacts valve seat, there will be severe cavitation phenomenon at the valve port. Although poppet does not impact valve seat, the cavitation come up is affected by the pressure difference at the port or vibration amplitude of the poppet. In addition, both of the flow pulsation of the hydraulic pump and the coupling between the poppet and pipeline system will lead the poppet to be unstable.

Modeling and Design of the Automatic Pressure Regulating Valve in the Foam Firefighting System

“…96µL . There exists a minimum value of b 3 (or d 2 ) to ensure the valid solution of P X ∈ (P 2 , P 0 ) satisfying Equation (14). Figure 8a indicates that the critical diameter of diversion holes is found to be 7~7.5 mm;…”

“…There exists a minimum value of 𝑏 (or 𝑑 ) to ensure the valid solution of 𝑃 ∈ (𝑃 , 𝑃 ) satisfying Equation (14). Figure 8a indicates that the critical diameter of diversion holes is found to be 7~7.5 mm; at 𝑑 ≥ 7.5 mm, 𝑃 is very stable with a constant equilibrium value of 𝑃 ≈ 1.61 MPa, which is almost unaffected by the change in 𝑑 ; at 𝑑 = 7 mm, however, 𝑃 experiences a sudden decrease at 𝑡 = 0.015 s, attaining a lower equilibrium value of 𝑃 = 1.59 MPa.…”

“…Processes 2020, 8, x FOR PEER REVIEW 3 of 14 computational fluid dynamics (CFD) tool to simulate the dynamic behavior of poppet valves (e.g., Gomez et al [12]) and using the experimental visualization method to directly capture the valve vibrations [13,14]. Instability is an inherent issue for the spring-loaded poppet valves, which cannot be eliminated completely.…”

Numerical Experiments on Performance Comparisons of Conical Type Direct-Acting Relief Valve—With or without Conical Angle in Valve Element and Valve Seat

“…Fornaciari et al [5] dealt with experimental tests and numerical simulations (3D and 0D fluid-dynamic modeling) of a conical poppet pressure relief valve with flow force compensation. Min et al [6] studied the unstable vibration of the poppet and cavitation using visual experiments. Filo et al [7] used CFD to analyze an innovative directional control valve consisting of four poppet seat valves and two electromagnets enclosed inside a single body.…”

Effect of the balanced piston on the stability of hydraulic pilot-operated relief valve

“…4 Besides, many studies show that the spool motion damping coefficient, orifice size, spool half cone angle, pre-compression of the adjusting spring, and valve chamber volume all affect relief valve stability. [5][6][7][8][9][10][11][12][13][14] The other direction focuses on increasing the relief valve's stability. Many measures have been proposed to achieve this goal.…”