The double-acting K84 is composed of an highly extrusion resistant TPU sealing element, which is prestressed by a rectangular NBR ring. The K84 is distinguished by its extraordinary sealing function under both dynamic and static loads. If there is pressure on both sides, two sealing edges establish a secure media separation.



  • Thermoplastic polyurethane (TPU) stands out for its very high resistance to wear and extrusion resistance as well as its low compression set
  • Nitrile butadiene rubber (NBR) and TPU are resistant to hydraulic oils in accordance with DIN 51524 (Part 1–3) and flame-resistant hydraulic fluids (HFA, HFB, HFC) as well as lubricating oils and greases based on petroleum oil
  • Channels on the facing surface ensure a rapid pressure build-up
  • A special geometry allows a hydrodynamic lubricating film while reducing friction and minimizing the stick-slip effect
  • During operation, the rectangular ring provides an uniform pressure distribution and twist-protection
  • Accidental twisting during installation can be controlled by means of a built-in marking in the inner surface of the rectangular ring