Our Style PSU piston seal, or uniring, is a laminated one piece double acting seal made of cast polyurethane. The tough outer layer is highly resistant to abrasion and is impregnated with molybdenum disulfide to reduce friction. The softer inner layer acts as a static seal and also energizes the OD to make full contact with the bore. This seal may be used to replace an existing Uniring or other seals of the same dimensions - O-rings, O-rings with back-ups, T-seals, U-seals, etc. NOTE: Piston diameter 'I' dimensions are given for pistons without wear rings.

IRON PISTON RINGS
When using iron piston rings, it is crucial to use the correct groove design for proper performance of the cylinder. Please use the following guidelines when cutting an iron piston ring groove

GROOVE WIDTH:

To permit the ring to slide freely into the groove, the groove must be at least 0.001 in. wider than the maximum piston ring width with a tolerance of +0.003 in./-0.000 in.

GROOVE DEPTH:

Grooves must be at least 0.015 in. deeper than the maximum radial wall thickness of the piston ring with a tolerance of +0.003 in./-0.000 in. This is to avoid any possibility of the ring bottoming in the groove when the ring is compressed to its working diameter.

RADIAL CLEARANCE:

The radial clearance between the cylinder bore and piston should be less than 1/3 of the radial wall thickness of the piston ring to ensure sealing effectiveness.

END CLEARANCE
End clearance on piston rings depends on ring design, material and application. The following end clearances are provided as a standard for hydraulic cylinder applications.

Style ST wiper rings are precision molded from 90A durometer urethane. Flexible enough to easily snap into a groove yet tough enough to handle difficult rod wiping applications. 'V' tagged wipers are constructed of fluorocarbon.

Product Codes ending in SH are designed with a Slotted Heel. The slots in the heel allow excess hydraulic fluid to bypass the wiper, preventing wiper blowout.

Style ST-E is a light to medium duty urethane wiper ring with a square shoulder, similar to our standard ST style wipers but with different dimensions.

QR, BUNA-N QUAD RINGS
The four-lobed design of these seals provides twice the sealing surface of ordinary o-rings. They can be used in a variety of static and dynamic sealing applications including rotary, reciprocating or oscillating motion.
NOTE: Last three digits of part number corresponds to standard o-ring dash numbers (568-218 = QR-4218)
V = FLUOROCARBON

SFS SPLIT FLANGE SEALS
FOR 4-BOLT SPLIT FLANGE CONNECTORS
Flange seals are a one piece dual durometer urethane static seal. The black outer part is a tough, extrusion resistant 95 Durometer and the yellow inner layer is 57 Durometer that has low compression set and excellent sealing properties. These seals are a direct replacement for o-rings and do not require modification to any split flange groove.