Wiper Seals

Wiper seals, also known as scraper seals or rod wipers, are specialized sealing elements installed at the external end of hydraulic or pneumatic cylinder rod glands in linear motion systems. Their primary function is to mechanically scrape off dust, dirt, moisture, and other external contaminants from the rod surface as it retracts into the cylinder, preventing these particles from entering the internal sealing system. This protective action preserves the integrity of primary seals, reduces wear on rod surfaces, extends component lifespan, and maintains system efficiency by minimizing friction and preventing fluid contamination.

Wiper seals operate on a mechanical scraping principle combined with elastic sealing contact. As the rod retracts into the cylinder, the seal's lip (typically made of flexible material like polyurethane or rubber) maintains constant contact with the rod surface. This contact creates a wiping action that physically removes contaminants adhering to the rod. The seal's geometry includes a scraping edge that directs contaminants outward, while its elastic properties ensure consistent contact pressure across varying rod positions and temperatures. Some designs incorporate secondary lips or exclusionary features to handle different contaminant types.