The Hunger compact slide ring seal type GKD is used
to seal and guide pistons on double-acting hydraulic
cylinders. In standard form it is suitable for use with all
The GKD consists of 4 parts, an elastic inner ring of
PUR, a slide ring of abrasion-resistant PTFE-Bronze
compound and two bearing rings of a pressure-resistant
The Hunger bearing rings make contact with the cylinder
wall; there is no metallic contact between the piston
and the cylinder body.
The internal elastic ring energises the slide ring to press
it against the cylinder wall providing a sealing function
at zero pressure. The onset of pressure compresses
the elastic ring increasing the radial forces acting on
the slide ring, thereby increasing the sealing effect.
Uke the slxJe ring, me two beanng rings aiso s« on the
olastic ring The pressure-mduced compression ot the internai
ring forces the two beanng rings, and the slide ring, agamst
the cylinder wall so that there is zéro clearance befween
bearing rings and cylinder wal Even rf me cylnder tube expands
undec pressure the seal will adapt to the radiai deformation
maintaining both zéro gap and the seatng functon.
When combmed wtth a surface finish Rt 0.1 - 0.3 pm of the cylinder tube, minimum friction is achieved The seal has an excellent efficiency with no stick-slip effect due to stiction.