Wiper seals
Hydraulic cylinders operate in a variety of applications and environmental conditions, including exposure to dust, debris or outside weather conditions. To prevent these contaminants from entering the cylinder assembly and hydraulic system, wiper seals (also known as scrapers, excluders or dust seals) are fitted on the external side of the cylinder head (fig. 1).
Wiper seals maintain sealing contact to the piston rod when the equipment is stationary (static, no reciprocating motion of rod) and in use (dynamic, reciprocating rod), whereas the tolerance for the rod diameter d is determined by the rod seal. Without a wiper seal, the retracting piston rod could transport contaminants into the cylinder.
The outside static sealing of the wiper seal within the housing is also important to avoid moisture or particles from entering around the outside of the wiper seal.
Press-in wiper seals
| Profile | Description |
PA
 | Polyurethane press-in wiper seal; steel retaining ring; single-lip design; lip protrudes from head; small radial cross section
→ Additional information → Profile data → Size list metric [pdf] |
MCW
 | Polyurethane press-in wiper seal; steel retaining ring; effective single lip design that sits flush with head; suitable for heavy duty applications
→ Additional information → Profile data → Size list metric [pdf] → Size list inch [pdf] |
PAD
 | Polyurethane press-in wiper seal; steel retaining ring; double-lip design improves rod sealing system performance
→ Additional information → Profile data → Size list metric [pdf] |
PADV
 | PAD design with a vent hole in the inside-facing lip
→ Additional information → Profile data → Size list metric [pdf] |
Snap-in wiper seals
| Profile | Description |
DTW
 | Polyurethane snap-in wiper seal; singlelip design; static seal lips on the outside surface and outside face; notches on inside edge of heel
→ Additional information → Profile data → Size list metric [pdf] → Size list inch [pdf] |
DX
 | Polyurethane snap-in wiper seal with nitrile rubber O-ring; single-lip design; patented profile for heavy duty applications; notches on inside edge of heel
→ Additional information → Profile data → Size list inch [pdf] |
HW
 | Polyurethane snap-in wiper seal; double- lip design improves rod sealing system performance
→ Additional information → Profile data → Size list metric [pdf] → Size list inch [pdf] |
