Simulation and validation of a wobble plate pump with a focus on check valve dynamics

Digital hydraulic piston pumps that use electrically controlled on/off valves to individually control the flow from each piston is a promising technique as these pumps are highly efficient at part displacement and respond quickly. However, digital pumps can still use check valves on the inlet, a fact that makes analysing wobble plate pumps (WPP) and their check valves interesting. Here, we measured the cylinder pressures of a WPP and compared these results with results from a simulation model we developed. In addition, we used linear analysis to investigate how different design parameters affect the valve’’s behaviour. From the measurements we found that the cylinder pressure is clearly affected the flow from other pistons and also that the system is not as stiff as expected. From the linear analysis, a criterion of how to design the valve to avoid instability was derived.