Rod Seals

Rod seals are used in hydraulic and pneumatic cylinders and are one of the most critical seals on any type of fluid power equipment. The seals help prevent pressurised hydraulic fluid within the cylinder from leaking out, and prevent dirt and contaminants getting into the cylinder.

Function of a hydraulic rod seal

Rod Seals are typically single acting/uni-directional but can also be provided in a double acting/bi-directional configuration if the application demands. Installed inside the cylinder gland or housing, they provide a tight seal against the piston rod.

Rod seals perform the difficult balancing act of creating a seal at both high and low pressure, often in combination with alternating high and low temperatures. Therefore, it is important to select the correct material and profile of the rod seal to align with the application’s requirement.

Rod seals paired with wiper seals

Contamination is the most common reason for hydraulic system failure. To prevent this, and to give the best sealing performance, a rod seal is paired with an appropriate wiper/scraper. This creates a second layer of protection, which protects a hydraulic system against external contaminants such as dirt and outside weather conditions.

Particular attention should be paid when pairing the rod seal and the wiper seal. For example, if a rod seal is paired with an aggressive wiper, the wiper can scrape off the thin film of oil that remains on the rod during the return stroke after the rod passes through the rod seal, resulting in system leakage.

In heavier duty applications, a rod seal can be combined with a secondary buffer seal for a more robust sealing effect.

Speak to our technical team for advice.