Explain how a double acting pneumatic cylinder operates. - Leaving Cert Engineering - Question (v) - 2020

A double acting pneumatic cylinder functions by utilizing compressed air to produce motion in both directions: outward and inward.

Outward Stroke

When the cylinder is activated for an outward stroke, compressed air is supplied to one end of the cylinder. This air pressure pushes the piston away from the cylinder housing, creating the desired linear motion. As the piston moves, the air on the opposite side of the piston is vented out, referred to as exhaust.

Inward Stroke

For the inward stroke, the flow of compressed air is redirected to the opposite side of the piston. This action pushes the piston back into the cylinder. During this phase, the air that was previously on the side of the piston being compressed is expelled as exhaust.

In summary, a double acting pneumatic cylinder requires a compressed air supply to facilitate the outward movement of the piston and a separate supply to reverse the direction, allowing for efficient and controlled linear motion.