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Header X-ring

Static Seals X-ring

A X-ring is a double-action sealing element for either static or dynamic applications and has an x-shaped profile with four sealing lips.
  • radial - dynamic applications
  • axial/radial - static applications
Due to the large variety of elastomeric compounds, virtually all solvent and gaseous media can be applicable. The advantage of this sealing cross section is that the parting line of the tool lies outside of the sealing area. Furthermore, a lubricant reservoir can build up in between the sealing lips and this development is of great benefit during dynamic applications. X-rings are installed using similar groove dimensions as those of standard O-rings and are available in a variety of common elastomer materials. The most common of these are NBR, HNBR, FKM, EPDM, CR, VMQ and FVMQ. Dimensions are available according to AS 568 (inch sizes).

X-ring

Fields of application
static
dynamic
single acting
double acting
Linear
Rotating
oszilating
Main use for static and dynamic applications, its design prevents a twisting of the cord
Materials elastomers
Advantages
  • extremely versatile, also in dynamic applications 
  • greater stability as O-rings
  • no twisting in the groove 
  • long service life
  • lubricant reservoir between the sealing lips
  • lower friction compared to the O-ring 
  • parting line outside the sealing area

Fields of application
X-rings are used in a wide variety of technical application fields. Compared to the O-ring, the X-ring can be used better for dynamic sealing. Its range of application is limited by the respective pressure and speed.

Main fields of application:

  • radial-dynamic sealing 
  • axial-static sealing
  • radial-static sealing 

 

Technical values

Materials
Pressure static up to 40 MPa (from 5 MPa with Back-up ring)
linear up to 30 MPa (from 5 MPa with Back-up ring)
rotatory up to 15 MPa (from 5 MPa with Back-up ring)
Temperature -30°C / +80°C (material dependent)
Speed linear up to 0,5 m/s
rotary up to 2 m/s
Pressure static up to 40 MPa (from 5 MPa with Back-up ring)
linear up to 30 MPa (from 5 MPa with Back-up ring)
rotatory up to 15 MPa (from 5 MPa with Back-up ring)
Temperature -30°C / +150°C (material dependent)
Speed linear up to 0,5 m/s
rotary up to 2 m/s
Pressure static up to 40 MPa (from 5 MPa with Back-up ring)
linear up to 30 MPa (from 5 MPa with Back-up ring)
rotatory up to 15 MPa (from 5 MPa with Back-up ring)
Temperature -20°C / +200°C (material dependent)
Speed linear up to 0,5 m/s
rotary up to 2 m/s
Pressure static up to 40 MPa (from 5 MPa with Back-up ring)
linear up to 30 MPa (from 5 MPa with Back-up ring)
rotatory up to 15 MPa (from 5 MPa with Back-up ring)
Temperature -40°C / 130°C (material dependent)
Speed linear up to 0,5 m/s
rotary up to 2 m/s
Maximum values temperature, speed and pressure are simultaneously not applicable! The values vary in dependence of material and media. For technical queries please contact our application consultants – we have the right solution for you. 
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X-ring

X-Ring

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Square Ring
Further to Square Ring
2-X-Ring Definition_EN

Definition of X-ring dimensions and ordering sizes

  • inside diameter d1 from approx. 0,74 mm to 600 mm 
  • Cross section w  from approx. 1,02 mm to 6,99 mm


Sealing effect

The sealing effect of the X-ring is the result of the axial or radial compression of the rings cross section when it is installed. Due to its profile and better distribution of the pressure, a high sealing effect is achieved. The system pressure additionally increases the pressure on the sealing surfaces.

3-X-Ring Pressungsverlauf_EN

Design Information

In general
For all applications, we recommend selecting the largest possible cross section in relation to the inner diameter d1 when selecting the cross section "w". If the tolerance is unfavorable, the next largest cross section should always be used. This applies in particular to dynamic applications.


Stretching/compression:
In dependence of the given application at a radial installation, X-rings can be:

  • expanded by max. 6%
  • compressed by max. 3%

Installation precompaction
Depending upon the application, the following values should be achieved: 

  • dynamic sealing 6 – 18%
  • static sealing 8 - 25% 
Surface quality:
In order to achieve an optimum sealing effect, the contact surfaces must meet minimum requirements. The permissible roughness values must be adhered to, especially in dynamic applications.
4-X-Ring Spaltextrusion_EN

Gap widths: 
The permissible gap "S" is determined by the system pressure, the cross section and the hardness of the X-ring. If the sealing gap is too large, gap extrusion can damage the X-ring. The use of Back-up rings is generally recommended from a pressure of approx. 5 MPa. It should be noted that the groove width for the X-ring back-up ring combination must be enlarged.

X-ring as rotatory seal:
The X-ring can be used to seal rotating shafts in applications with short switch-on times. It should be noted that the inner diameter of the X-ring should be approx. 2% - 5% larger than the shaft diameter to be sealed.

X-Ring Montage

Installation instructions

To exclude possible sources of error, ensure that the following points are observed for the sealing function when installing X-rings:

  • defined insert inclinations, burr free, rounded-off transition,
  • surface quality Ra < 0,4µm, Rz < 1,6 µm 
  • burr-free rounded-off holes and slits  
  • lubrication (without any solid additives) 
  • installation tools to pass over sharp edges and corners (e.g. threads) 
  • dirt-free sealing surface 
  • the X-ring must not be overstretched 
  • the X-ring must not be warped or twisted
Mr. Andreas Raidt
Your contact person for

Technology - General sealing topics, special constructions

Mr. Andreas Raidt
Head of Engineering
Do you have any questions, ideas, or suggestions? We are more than happy to assist you with advice. In person, over the phone, or digitally.

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