Telescopic hydraulic cylinders are structurally different from conventional hydraulic cylinders. A telescopic hydraulic cylinder consists of several sections. Each of the sections acts as a piston and a housing for the next inner section. When the hydraulic fluid is under pressure, the first piston with the largest diameter starts moving and extends until it stops. After that, the next section, which is inside the first one, begins to move. In this way, all subsequent sections are extended until the necessary total length of the telescopic cylinder is reached. This design ensures that a telescopic hydraulic cylinder is compact when retracted. The size of a retracted cylinder can be smaller by up to 40% of the extended size.
Application of Telescopic Hydraulic Cylinders
Such design advantage allows the use of telescopic hydraulic cylinders in places where the operating space is very limited for a hydraulic cylinder of conventional design both when retracted and extended. Due to their design, telescopic hydraulic cylinders are used in various road and construction machinery, oil production equipment, all kinds of lifting machines and manipulators.
Just like classic hydraulic cylinders, telescopic hydraulic cylinders are divided into two main types:
Single-acting telescopic hydraulic cylinders
In this type of cylinder, the hydraulic fluid is pressurized only to extend the pistons. In order to extend each section, different levels of pressure are used. The reverse movement of the pistons is initiated by the weight of equipment being lifted.
Double-acting telescopic hydraulic cylinders
To operate this type of hydraulic cylinders, the hydraulic fluid is fed under pressure in both directions of operation. This type of hydraulic cylinders is more complex and therefore more expensive to produce. That is why single-acting telescopic hydraulic cylinders are most commonly used.
There are also two different ways to supply hydraulic fluid. The first one is a direct-flow supply where the hydraulic fluid is fed into all rod cavities simultaneously. The second way is by using pressure valves which are located at the bottom of each section of a hydraulic cylinder. The valves open one by one after each section is fully extended.
The Eurobalt manufacturing group is ready to produce for you telescopic hydraulic cylinders of any design and complexity with any type of hydraulic fluid supply for different operating conditions.