Cylinders are the means to deliver “work” from the fluid power system. They convert the pressure energy into force and linear movement by means of a piston running in the bore of a sealed tube. The piston is attached to a piston rod which exits the cylinder through a sealed gland to allow the motion to be transmitted to external machine elements.

For the piston to move, pressure is applied to one side of it whilst pressure is reduced or removed from the opposing side. The resulting differential in force across the piston causes it to move towards the direction of lower force. To return the piston back in the opposite direction the pressure across it is reversed.

The fluid control to the cylinder is by means of a directional control valve which in turn is actuated by electrical, fluid or spring inputs or a combination of these.