In dynamic pressure pump, work is transferred to fluid flowing over rotating blades of the impeller by changing direction of flow. This increases both pressure and velocity of fluid; mechanism of increase in pressure will be discussed later. Therefore fluid flows in the direction of increasing pressure and chances of separation and back flow are quite high, which results in decrease in efficiency and stable operation of the pump. For this reason their use is limited to those applications where moderate pressure rise is required. There are preferred as compared to reciprocating pump when required volume flow rate is high and/or pressure rise is not large. Dynamic pressure type system include both turbine and rotary pump, which can handle compressible as well as incompressible fluids. Further, fluid may flow from outer to inner side or vice versa, as in radial flow machines or along the shaft axis of such machines. Methods like multi-staging have been developed to use these for high-pressure applications also. It is a technique in which discharge of the first stage is fed to the next stage and so on. This way a high-pressure ratio can be obtained. Here pressure ratio is defined as ratio of discharge pressure to suction pressure