Experimental research on performance of water hydraulic internal gear pump

Internal gear pumps have significant advantages over other types of pump, such like high operating pressure, efficient transmission of energy, long service life, little pressure ripples and low noise emissions. Due to the nature of water, such as, low viscosity, poor lubricity and high vapour pressure, the performance of water hydraulic internal gear pumps is totally different from the oil ones. Using tap water as working medium, the experiments of internal gear pump are implemented and the performances are obtained. The results indicate the floating plates are the key components of water hydraulic internal gear pumps which decide the efficiency and service life of the pumps. Then, the pressing forces acting on the floating plates and the contact stresses are calculated. Finally, the causes of wear failure of floating plates are investigated and some design principles in water hydraulic internal gear pumps are also proposed.