O-ring seal GD1000K series

profiledNBRPTFE

The HUNGER slide ring piston seal type GD1000K is used to seal and guide pistons on double-acting hydraulic cylinders. The seal design and materials used make it particularly suitable for the most vigorous applications e.g. construction machine cylinders. Depending on material version all kinds of hydraulic fluids can be sealed. The seal can be used in standard form with mineral oils and water based fluids. Modified versions are available for use with other fluids. The GD1000K consists of 6 parts, a special shaped elastic ring of a modified NBR, a slide ring of abrasion resistant PTFE-Bronze-Compound which acts as the sealing ring, two lateral support rings of modified PUR and two bearing rings of pressure-resistant POM-Compound. The elastic ring energises the slide ring to press it against the cylinder wall, providing a sealing function at zero working pressure. The onset of pressure compresses the elastic ring which increases the radial force pressing the slide ring against the cylinder wall, thereby increasing the sealing effect. The two support rings prevent gap extrusion of the slide ring at high pressures. The special profile of the support rings encourages uniform fluid and pressure distribution to the elastic inner ring. The bearing rings positioned on the support rings, make contact with the cylinder wall; there is no metallic contact between the piston and the cylinder tube. When combined with a surface roughness of Ra 0.1 - 0.3 μm of the cylinder, minimum friction is achieved. The seal has excellent efficiency. Even at low speeds there is no stick-slip effect allowing good positioning control.