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What is a hydraulic cylinder?

Have you ever wondered about the secret behind the fluid, powerful movements of the machines that surround us? How is it possible to lift colossal loads with millimetre precision? Welcome to the world of hydraulic cylinders, the unsung heroes of modern engineering. In this article, after exploring the operation of a hydraulic cylinder, we'll be looking at the crucial role it plays in a number of areas, and highlighting the advantages it offers over other technologies.

What is a hydraulic jack ?

Définition du vérin hydraulique - Information technique | Hänchen

A hydraulic cylinder is a device used to convert hydraulic energy into linear mechanical movement. It works by using the pressure of a hydraulic fluid to move a piston in a cylinder, generating a force that can be used to lift, move or actuate heavy loads in a variety of industrial and mechanical applications.

What are the components of a hydraulic cylinder ?

Composants pour vérins hydrauliques - Eurobalt Engineering

La composition of a hydraulic cylinder consists of a cylinder, piston, piston rod, seals, hydraulic fluid and inlet/outlet ports.

- Cylinder

This is the main part of the hydraulic cylinder. It is a robust cylindrical tube, usually made of steel, which houses the other internal components. The cylinder is designed to withstand the high pressures generated by the hydraulic fluid.

- Piston

The piston is a movable element located inside the cylinder. It is usually a solid cylinder or rod that moves along the axis of the cylinder. The piston separates the cylinder into two distinct chambers: the chamber on the rod side (piston side) and the chamber on the head side (opposite the piston).

- Piston rod

This is a solid rod that extends from the piston through one end of the cylinder. It transmits the force generated by the movement of the piston to the load to be moved. The piston rod is usually chrome-plated to reduce friction and improve sealing.

- Sealing joints

Seals are essential elements in maintaining the tightness of the hydraulic fluid inside the cylinder. They are fitted around the piston and piston rod to prevent fluid leaks and ensure trouble-free operation. Seals can be made of rubber, polyurethane or similar materials.

- Input/output ports

These are the points where the hydraulic cylinder is connected to the hydraulic lines. They allow pressurised hydraulic fluid to enter the chamber on the rod side and fluid to escape from the chamber on the head side, or vice versa, depending on the desired movement.

- Hydraulic fluid

Hydraulic fluid is the liquid used to transmit pressure to the hydraulic cylinder. It fills the cylinder chambers and enables the piston to move. Hydraulic fluids must have appropriate properties, such as good viscosity and resistance to wear, to ensure optimum operation of the cylinder.

How do hydraulic cylinders work ?

Gamme de vérins hydrauliques 260 bar | Liebherr

When pressurised hydraulic fluid is introduced into one of the cylinder chambers, it pushes the piston in the opposite direction, resulting in a linear movement. The force generated by the movement of the piston is transmitted through a piston rod, which is connected to the load or mechanism to be moved. By controlling the pressure of the hydraulic fluid, it is possible to regulate the speed and force of the cylinder's movement, offering great flexibility and precision in a variety of industrial and mechanical applications.

How is a hydraulic cylinder sealed ?

The sealing of a hydraulic cylinder is achieved through the use of specific seals and sealing components. These components are designed to create a hermetic barrier between the different parts of the cylinder, preventing hydraulic fluid leaks.

Seals, usually made of rubber or polyurethane, are strategically placed around the piston and piston rod to prevent hydraulic fluid from escaping. They are designed to withstand high pressures and variable operating conditions.

In addition, guide rings can be used to maintain the correct alignment of the piston and piston rod, minimising friction and contributing to sealing.

In addition, the fitting a hydraulic jack is directly related to the way in which the seal is made. Correct installation of seals and other sealing components is essential to ensure optimum cylinder performance and avoid fluid leakage problems.

Accessories and options for hydraulic cylinders

Bien choisir un vérin hydraulique, pneumatique ou électrique ? - Nexa Industries - Matériel et équipements industriels

The accessories and options for hydraulic cylinders are designed to meet specific needs and improve performance in different applications. Here are a few examples:

- Position sensors

They enable the position of the cylinder to be measured accurately and provide real-time information on its position. This enables more precise control of cylinder movement and facilitates process automation.

- Pressure sensors

They are used to measure the pressure of the hydraulic fluid inside the cylinder. They enable the pressure to be monitored and controlled, ensuring that the cylinder operates safely and efficiently.

- Shock absorbers

These devices are used to reduce shock and vibration when the cylinder moves, which can extend its life and improve comfort of use. They absorb the kinetic energy generated during sudden stops of the cylinder.

- Discharge valve

A relief valve, also known as an overpressure valve, is used to protect the cylinder from potential overpressure. It diverts excess pressure back to the hydraulic reservoir, preventing damage to the cylinder.

How do you choose your hydraulic jack ?

To choose the right hydraulic cylinder, it is essential to consider a number of key factors.

First, assess the load and pressure requirements of your application, taking into account the forces needed and the working pressures.

Next, consider the required stroke of the cylinder, i.e. the distance the piston must travel.

Make sure you also consider the physical dimensions of the cylinder, including length, diameter and overall configuration. It's important to check the compatibility of the cylinder with your existing hydraulic system, particularly in terms of connections and fluid flow.

Finally, don't forget to consult the manufacturer's specifications to ensure that the cylinder is suitable for your specific application in terms of service life, working environment and safety standards.

How much does a hydraulic cylinder cost ?

Le price of a hydraulic jack can vary depending on the size and capacity of the cylinder, as well as its quality and brand. What's more, any additional accessories or options you choose to include with the cylinder will also have an impact on the total cost.

Ideally, you should consult specialist suppliers such as Au Comptoir Hydraulique for accurate, up-to-date quotes.

What are the common failures of a hydraulic cylinder?

The operation of hydraulic jacks can be affected by fluid leaks, seal wear, piston and rod wear, overheating problems.

It is important to note that regular maintenance, inspection and appropriate replacement of worn components can help to prevent these common failures and ensure that it operates smoothly.

How do I dismantle a hydraulic cylinder ?

Although it is essential to know how to dismantle a hydraulic cylinder, however, you should be aware that this can be a complex operation requiring specialist skills and knowledge.

For this reason, it is advisable to call in a qualified professional to avoid damaging the cylinder or compromising the safety of the operation.

How do I unblock a hydraulic cylinder ?

If you would like to know how to unblock a hydraulic cylinder, basically, you first need to check the hydraulic pressure and connections, bleed the air from the system, check the seals and lubricate the components.

However, if the problem persists, it is advisable to call in a professional for a precise diagnosis and resolution.

Still on the same theme

- Functional principle of a hydraulic cylinder

- Type of hydraulic cylinder

- Applications of hydraulic cylinders

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