Fig. 17.1 Standard test setup for airflow coefficients. Flow meter may be placed upstream or downstream. (Courtesy of the National Fluid Power Association, Milwaukee, WI.) Also see Fig. 17.6.
One easy answer-unfortunately practiced widely-is to make all the valves and piping the same size as the port on the final power element. For example, if the air cylinder port is 1.0 in. , make all the control valves 1.0 in. It's a conservative solution if you don't mind an occasional valve 10 times larger than needed or a pipeline so large in diameter that it acts as a plenum and slows down response to a pressure change.