In a double acting hydraulic cylinder the working fluid acts on both sides of the piston of the cylinder in an alternative manner. For connecting the piston of the double acting hydraulic cylinder with the external mechanism there is a hole at one end of the cylinder. Through this hole the piston rod is connected and to prevent the leakage of the working fluid from the cylinder a stuffing box is fitted with the cylinder. The basic objective of using double-acting hydraulic cylinder is produce force in both directions of the piston of the cylinder. These cylinders have ports at both the ends for retraction and extraction of the piston. This is the biggest advantage of the double-acting hydraulic cylinder as there is no need of external force to moving the piston in both directions for retracting or extracting.
In case of a single acting hydraulic cylinder the plunger extends when hydraulic fluid is pumped in high pressure into the cylinder. For retracting the cylinder back to the reset position, the plunger is either retracted by a return spring or by load or simply by gravity. But in double acting hydraulic cylinder the plunger is retracted when the hydraulic fluid is pumped in high pressure into the top port of the cylinder and that forces the plunger back to its reset position. While using the double acting hydraulic cylinder this process can be done quickly and gradually with high precision, if required.
Though the mechanism of double acting hydraulic cylinder is more complex than single acting hydraulic cylinder, it is preferred option if the job demands more precise operation. The faster retracting mechanism of double acting hydraulic cylinder is another advantage that is of great advantage in jobs where repetitive actions like Jack and Crib are required. If you need a controlled retraction the double acting hydraulic cylinders are indispensable.