X-Rings

Description
X-rings are twin-action 4-lipped seals with an almost square cross-section profile. The X-rings achieves its sealing effect by being installed and compressed within an axial or radial installation housing. Under operating conditions, the pressure of the medium reinforces the sealing function.

Hardness
X-ring hardness is usually in Shore A, or IRHD.

Benefits

• A high degree of stability for dynamic application, as the X-ring is not susceptible to rolling within the groove (twisting) due to its almost square cross-section.
• X-rings require a lower degree of radial pretensioning. This gives rise to less abrasion due to the lower contact pressures in play.
• It is possible for a lubricant reservoir to be created between the sealing lips.
• Optimised sealing effect due to superior distribution of pressure over the almost square cross-section.
• No adverse effect created by the mould-separation ridge as unlike the O-ring, this is not located at the outer diameter but between the actual sealing lip

Fields of application

X-rings are comparable with the O-ring in their handling and use. For example, they are used for the radial and axial sealing of flanges, sleeves and covers (static application) and for sealing pistons and rod seals, rotating shafts and helical movements (dynamic). X-rings are used primarily for dynamic applications, as they require less pretensioning than O-rings and therefore give rise to less abrasion.

Materials
NBR -  Good chemical resistance to mineral oils and greases, hydraulic oils H, HL, HLP, non-inflammable hydraulic pressure fluids HFA, HFB, HFC to approx. +50°C and water to max. +80°C 
FPM – Good chemical resistance to mineral oils and greases, synthetic oils and greases, engine, transmission and ATF oils to approx. +150°C, fuels, non-flammable hydraulic pressure fluids HFD, aliphatic, aromatic and chlorinated hydrocarbons, water to max. +80°C, excellent resistance to weathering, ozone and ageing, very low gas permeability (and therefore excellent for vacuum application) and resistance to a wide range of chemicals.

Housing
The installation housings (grooves) for O-rings should if possible be produced with right angles and should be processed with care. Burrs, scratches and notches should be avoided. The dimensions for the required depth and width of the groove depend on the particular application and cross-section.