Basic Type Of Hydraulic Cylinder

Like traditional hydraulic cylinders, telescopic hydraulic cylinders are divided into single-acting and double-acting types. The single-acting telescopic cylinder extends under hydraulic pressure and contracts by gravity or some external mechanical force. Single-acting cylinders are always used in applications on cylinders for certain forms of load. The classic single-acting telescopic applications are dump trucks and dump trailers. Pressurized oil extends out of the telescopic cylinder in order to raise one end of the dump body. When the pressure is released, the weight of the dump body forces the oil to drain from the cylinders and then retract.
Double-acting telescopic cylinder is driven by two-way hydraulic pressure.
They can be used in applications where neither gravity nor external force can retract the cylinder. They are very suitable for non-critical positioning applications, and require a large amount of load expansion movement. Typical applications are packer ejector cylinders in garbage trucks and transfer trailers. The horizontally mounted cylinder pushes the pressure plate to compress the load, and then it must be retracted together with the pressure plate to add more materials. Gravity cannot help, so double-acting hydraulic cylinder is used.