A single acting hydraulic cylinder is, at first glance, a relatively simple piece of machinery. It’s essentially a cylinder on a rod. The function of the cylinder, however, is vitally important and can be rather complex. They are useful in a variety of applications and have certain advantages over other types of cylinders.
The Function of a Hydraulic Cylinder
A hydraulic cylinder is a cylinder that gets pushed by fluid (often a type of oil) to lift something or move a part in a machine. The hydraulic fluid can create considerable pressure, meaning that the cylinder can provide equally considerable force to move heavy objects. In a double acting cylinder, there is fluid on both sides of the cylinder, allowing pressure to be increased on either side to move the cylinder back and forth. In a single acting cylinder, the fluid pushes the cylinder in one direction, but gravity, a spring or some other force is relied upon to push the cylinder back when the fluid pressure is reduced.
Advantages of Single Acting Hydraulic Cylinders
Single acting cylinders are a simpler design than other cylinders, which in turn makes them cheaper and less likely to break down, and also a little easier to repair or replace. There is usually less fluid required in the system for a single vs. a double acting cylinder. These single acting cylinders do not require electricity and require less energy in general than other cylinders. They also tend to be smaller in installation length.
Applications for Single Acting Hydraulic Cylinders
A single acting hydraulic cylinder is best suited for applications that involve lifting heavy objects, since gravity can then supply the force to return the cylinder to its starting point. Some examples would be a hydraulic jack, a scale or a bucket lifting mechanism on a piece of construction equipment. Similarly, these cylinders can be used as part of a hydraulic suspension system.
Hydraulic cylinders with single action are also handy for devices that do not require a return or have a manual return, such as doors, flaps, breeches and ejection devices. The introduction of a spring allows easier lateral movement for other hydraulic functions in vehicles and construction equipment, such as steering or rotation.
