Question: A pneumatic cylinder is used for an "accept-reject" circuit. Parts pass the station on a conveyor at the rate of two parts per second. Approximately 10% have to be recycled, because the finish is not acceptable. Average number of strokes per minute is then 0.10 (2)(60) = 12.
The cylinder has a 3-in. bore and 1-in. rod. Stroke length is 8 in. Operating pressure is 100 psi. You may neglect any temperature rise.
1. Calculate the average free air intake (cfm) required for this cylinder.
2. Suppose the part size can be represented by a 5-in. cube, and they are spaced 2-in. apart on the conveyor. The cylinder must extend 8 in., push the part into the reject bin, and retract 8 in. to clear the conveyor before the next part reaches the acceptreject station. Calculate the maximum free air intake to meet this requirement when the conveyor speed is 840 in/min.