Calculate the size of a gas filled accumulator needed to supply a hydraulic system with 25 litres of fluid from a pressure of 20 mpa to a pressure of 12 mpa. the accumulator is initially charged to a pressure of 8 mpa. the expansion and compression takes place rapidly and the gas is nitrogen with an adiabatic process exponent of 1,4. 8.1 an internal gear pump delivers 45 litres of hydraulic fluid per minute at a pressure of 20 mpa when driven at 1430 r/min. calculate the input power to the pump shaft and the displacement volume per revolution if the mechanical efficiency of the pump is 90% and its volumetric efficiency is 85%. 8.2