What is Single Acting Hydraulic Cylinder

Single acting hydraulic cylinder only extends by pressure from a pump and then retracts by the weight of the load or by an inbuilt spring. A Double Acting cylinder uses hydraulic power to both extend and retract.

Hydraulic cylinders convert the hydraulic energy within its fluid into mechanical energy or hydraulic force. This results in a linear (uni-directional) movement. In the case of a single-acting cylinder, the fluid-driven force operates only along one side of the piston. Common in most reciprocating engines, a single acting hydraulic cylinder usually extends through hydraulic pressure but returns through one of two means: gravity or spring. 

A spring is often responsible for returning the top of the cylinder and the piston rod into its original, retracted position. However, gravity can perform the same function. A classic example of this is a vehicular hydraulic jack. Other common applications include material handling, reciprocal engines, pumps and hydraulic rams. You can purchase single acting telescopic cylinders. They are most effective in various heavy-duty construction equipment where space is tight, and it is essential the piston rod return to the same position repeatedly.