Loaded U-Cup Seals

Loaded U-Cup Seal 

The O-Ring loaded U-cup is a single direction piston seal, meaning it can only seal if the pressure is coming from one direction. Since the sealing method is single directional, two loaded U-cups must be installed for dual direction hydraulic piston applications.

The lip designed is a straight lip design, so the loaded U-cup has good seal ability but also proves to be excellent at contamination removal away from the sealing lip. Overall, the shape of the loaded U-cup is a large rectangle that greatly adds to the stability of the seal. Also like most polyurethane seals, the loaded U-cup features an O-Ring energizer, which is designed to activate the seal at lower pressures.

Loaded U-Cups Seals, commonly referred to as “PolyPaks” or “Style 850” seals, are used in hydraulic applications.