Effects of pipe length on dynamic characteristics of port valves in a diaphragm pump for SCR urea dosing system

The motion of port valves is a primary aspect of achieving superior reliability and performance of a diaphragm pump. A simulation model coupled with the diaphragm pump and the piping system was built based on AMESim, and the influences of the pump speed and pipe length on the dynamic characteristics of port valves were analyzed. The flow rate and the working chamber pressure of a prototype pump were tested under different conditions on a test rig. Results show that the motion of discharge valve is more stable with the increase of pump speed, and that of the suction valve is independent on the pump speed. The oscillation amplitude and period of suction valve experience a severely increase as the suction pipe length increases, and these of discharge valve becomes larger with the increase of discharge pipe length. The simulation results show good agreement with the experimental data.