In hydraulic systems, seals are small but essential components. They reliably keep hydraulic fluid within the system, enable the required pressure build-up, protect the system from contamination and help reduce wear on moving components.

The poesia group offers more than 1,000 sizes and versions of hydraulic seals and supports customers in selecting the right solution – from piston and rod seals to wipers and guide strips.

Piston seals

Piston seals are fitted on the piston inside the cylinder. They prevent hydraulic fluid from flowing past the piston. This maintains the pressure in the respective cylinder chamber and ensures that force can be reliably transmitted to the piston.

Rod seals

Rod seals are fitted in the cylinder head and seal the moving piston rod to the outside. They prevent hydraulic fluid from leaking out of the cylinder. At the same time, they must withstand high loads and reliably cope with the repeated reciprocating movements of the piston rod.

Rod and piston seals

Depending on their design and installation arrangement, rod and piston seals can be used either as rod seals or as piston seals. In rod applications, they seal the moving piston rod to the outside. In piston applications, they prevent hydraulic fluid from flowing past the piston. This allows different sealing functions within a hydraulic cylinder to be covered by the same seal design.

U-cup seals

U-cup seals are dynamic sealing elements used, for example, to seal moving components. They are available in NBR (nitrile butadiene rubber) and PUR (polyurethane).

NBR offers good resistance to many mineral oil-based hydraulic fluids as well as good mechanical properties.

PUR provides high abrasion resistance and good mechanical properties. These U-cup seals are therefore particularly suitable for applications involving high mechanical loads and demanding requirements in terms of wear resistance.

Wipers

Wipers protect the inside of the hydraulic cylinder from the ingress of dirt, dust, moisture and other contaminants. They are fitted at the outer end of the cylinder and remove contaminants from the surface of the piston rod as it retracts into the cylinder.

This prevents dirt from reaching the rod seals and other sealing elements. It protects the sealing system and helps extend the service life of the hydraulic cylinder.

Guide strips

PTFE guide strips do not perform an actual sealing function. However, they guide the piston and piston rod within the hydraulic cylinder and absorb transverse forces. In doing so, they prevent direct metal-to-metal contact between moving and surrounding components. This contributes to smooth operation and helps extend the service life of seals and cylinder components.

Selecting the right hydraulic seals

The choice of the appropriate hydraulic seal depends on several factors: seal type and installation space, rod or cylinder diameter, operating pressure including possible pressure peaks, movement speed, temperature range, hydraulic fluid used, surface quality, operating conditions and type of movement.

A seal precisely matched to the application is essential for reliable operation and a long service life of the entire system.

Applications

Hydraulic seals are specialised products used in a wide range of applications. These include hydraulic cylinders, construction machinery, agricultural and forestry machinery, automotive engineering, production equipment such as lifting and conveying systems, as well as injection moulding machines and industrial automation.

Specialists at your side

The poesia group offers hydraulic seals and guiding elements in more than 1,000 sizes and versions. Depending on the seal type and application, materials including NBR, PUR and PTFE are used. If you have any questions about selecting the right solution, the poesia group’s specialists are available to assist you with their extensive expertise.

Easy online ordering

Once all technical specifications are known, seals can be conveniently ordered via the webshop, by phone or by e-mail. This ensures that customers receive the right products quickly and easily.