NBR + PTFE Bronze compound

K840B , K840G



FKM (Viton) + PTFE


NBR + PTFE + Graphite + Glass



K840 is an O-ring energized double lip wiper, which is designed to exclude dirt from entering the

cylinder and to collect traces of fluid passing the rod seal.

 K840 combines low friction double lip PTFE ring and rubber o-ring energizer to perform a high speed, efficiency and stable dust wiper.

 The K840 is a double acting wiper for use in low to medium duty hydraulic cylinders. It is a two piece design comprised of a filled PTFE cap that is energized by a standard size O-ring.

 The wiper and seal design of the K840 profile assists the primary rod seal in preventing leakage by helping seal fluid in the cylinder when the rod extends. When the cylinder rod retracts, the outside sealing edge prevents contamination from entering the system. K840 profile will retrofit non-Parker wipers of similar design.

 It has a special filled PTFE ring with a pre-loaded lip energized by an O ring. The lip is designed to have a contact area with the rod adequate to retain the media at low pressure. As high pressure acts on the O ring it compresses the lip against the rod increasing the contact area and the effectiveness of the seal.


Standard material: medium nitrile (NBR) elastomer.

Special materials: other elastomers to suit operating conditions, including fluoroelastomer (FKM) for high

temperature duties.

 PTFE sleeve

Standard material: bronze loaded PTFE.

Special materials: alternative grades of PTFE to suit specific applications.

 The special PTFE ring has the low frictional properties normally associated with this material but is strengthened by additives to reduce creep. It has a low breakout friction so stick-slip is eliminated.

Special features


Ø  High performance single-acting seal providing low wear and maintenance.

Ø  Low dynamic and breakout friction for instant response, smooth operation and reduced power consumption.

Ø  Protects primary seal from contamination

Ø  Extends seal life

Ø  Low friction no stick-slip

Ø  High strength machined PTFE wiper

Ø  Wide range of other materials and dimensions available for special applications 


Operating Conditions