Piston seals

Piston seals (fig. 1) maintain sealing contact between the piston and the cylinder bore. Differential pressures acting on the piston to extend or retract the piston rod can be in excess of 400 bar (5 800 psi). The pressure acting on the piston seal increases contact forces between the piston seal and cylinder surface. Therefore, the surface properties of the sealing surfaces are critical to proper seal performance (→ Counter-surface finish properties).

Piston seals are typically classified into single-acting (pressure acting on one side only) and double-acting (pressure acting on both sides) seals.

Double-acting piston seals

Single-acting piston seals

ProfileDescription
UNP

Polyurethane U-cup profile; single-acting; may be used in double-acting cylinders when using two seals in back-to-back arrangement; suitable for medium duty applications
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Size list metric [pdf]
Size list inch [pdf]

Rod seals that can be used as piston seals

These rod seal profiles are designed with similar inside and outside sealing geometry. Therefore, they can also be used as piston seals (→ Rod seals used as single-acting piston seals).

ProfileDescription
PTB

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Size list metric [pdf]
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STD

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Size list inch [pdf]
DZ

Additional information
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Size list metric [pdf]
Size list inch [pdf]
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