Hydraulic cylinders can be used to push, pull, or to lift loads. They are most commonly seen on heavy equipment, such as dump trucks, cranes, loaders or excavators, but they are also used throughout automated processing and manufacturing systems.
There are two basic options in how hydraulic cylinders work, but there are different types and design options. The two basic types of cylinders are the single acting and the double acting. A single acting cylinder has one port for hydraulic fluid to enter the cylinder to extend the rod. The cylinder is retracted through the weight of the load bearing down on the rod once the pressure from the hydraulic pump is removed. A spring inside the cylinder can assist with the retraction of the rod once the pressure is removed.
A double acting cylinder has two ports, one which is used to apply pressure to extend the rod and the load, and one that is used to push down on the rod to cause it to retract.
A welded single acting cylinder has a very streamlined design. Welding attaches the caps to the body of the cylinder without the need for the use of external tie rods. By choosing the single acting style, there is only one port and one hydraulic hose assembly required, simplifying design and installation while also taking up less space.
A correctly sized, built and installed single acting cylinder is a very durable and reliable cylinder in any type of application. With only one port and hydraulic hose, there is less maintenance on the cylinder.
It is important to keep in mind, ensuring the cylinder is in good condition and maintaining the hydraulic fluid is always essential in maximizing the life cycle and the performance of any hydraulic cylinder.