Rod Seals

Due to their importance in a hydraulic cylinder, rod seals should be mentioned first. A leak at this important point would lead to serious influences on the operating system and would cause damage to the environment. The rod seal must have a tight fit and make a perfect seal when in motion and motionless. For this reason, some types of seals include pre-loading elements (usually made out of NBR) to ensure a tight fit and seal even in a motionless or depressurized state. At higher operating pressures, additional support rings are used on the rod seal in order to avoid losing the seal.




Rod seals are mostly made out of PU, NBR or FPM, but a combination of elastomers and plastomers is also possible. The same applies here, PU rod seals are usually much more wear and tear resistant than those made from rubber materials. Depending on operating conditions, for example, at temperatures above 100°C (212°F), FPM seals are used. In pneumatic applications NBR is the preferred material for seals.