External-gear hydraulic pump 0.25 - 0.5 series

high-pressuretransfer

This chapter describes Marzocchi external single gear micropumps, ¡heir operating features and hew to select the right pump for the required application. Miaopumps are small hydraulic machines converting mechanical pcwer into hydraulic power. This section deals with rotary positive-dispbeement micropumps. In this type of micropump, a given volume of fluid flows from inlet to outlet at each shaft rotation (theoretical displacement}. Pressure depends on delivery line resistance to fluid Sow. As gear miaopumps only transfer fluid, they are subject to pressure generated by the circuit. Therefore, if system Sow rate and motor rotation speed are known, it is easy to select the right micropump displacement and its model. The diagram indicating flow rate variations according to speed and pressure, shows hat not oH the theoretically available fluid is transferred from inlet to outlet because of pump internal dripping. Dripping can be remarkably reduced through pressure axial compensating systems (as described at the beginning of this catalogue) but never eliminated. Dripping increases as circuit pressure increases.