Piston guide ring type kf

The piston guide ring type KF prevents metal parts from contacting each other and additionally absorbs occurring shear forces. As standard, it is made of the compound PTFE + carbon or PTFE + bronze; other materials are available.

Given its good media resistance, the piston guide ring can be used in several media ranging from mineral oil-based hydraulic liquids, environment-friendly hydraulic liquids and water-oil emulsions to flame-resistant hydraulic liquids.

Piston guide rings offer very good gliding behavior, good emergency running properties and also a high wear resistance. Additionally, they help to attenuate mechanical vibrations.

Application media

  • Mineral oil-based hydraulic liquids
  • Water-oil emulsions
  • environment-friendly hydraulic liquids
  • Flame-resistant hydraulic liquids

Application range

Pressure resistance: max. 15 N/mm² at 25 °C, max. 12 N/mm² at 80 °C, max. 8 N/mm² at 120 °C

Speed: approx. up to 15 m/s

Temperature: – 30 °C to +200 °C

Surface finish

Roughness depth Ra Rt
Running surface ≤ 0,3 µm ≤ 3,0 µm
Groove base ≤ 1,6 µm ≤ 16,0 µm
Groove flank ≤ 1,6 µm ≤ 16,0 µm

Installation dimensions

Cylinder ø D Gap Z Gap size S Radius R max.
< 40,0 1,0 – 3,0 0,25 – 0,4 0,2 für ø D ≤ 250,0
0,4 für ø D ≤ 250,0
< 80,0 3,0 – 6,0 0,25 – 0,5
< 140,0 5,0 – 10,0 0,3 – 0,6
< 340,0 7,0 – 14,0 0,4 – 0,6

PTFE profile ring material

PTFE + bronze

Used preferably for hard counter running surfaces; is a standard material in hydraulics

PTFE + carbon/graphite

Used with softer counter running surfaces such as stainless steels, aluminum and bronze, also preferably where the media water and steam play a role.

For other possible materials see our overview of PTFE materials in the technical information section.

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