STAUFF Connect: Pre-stressed O-Rings of FKM (Viton®)

Pre-stressed O-rings of defined tube fitting components of the STAUFF Connect product group – to date made as delivery standard from NBR (Buna-N®) – are changed to FKM (Viton®) as the standard material as announced. Directly affected by the change-over are all DKO-type tube fittings with  24° taper / O-ring:

  • Straight male stud fittings FI-EGED
  • Straight unions and reducers FI-SNV
  • Straight reducers for tube ends FI-REDSD
  • Adjustable elbows FI-EWD (90°) and FI-EVD (45°)
  • Adjustable T and L fittings FI-ETD and FI-ELD
  • Gauge fittings FI-EMAD
  • Blanking plugs FI-VD

Also changed are FI-BA flared cone adaptors which are used for the adaption of metric tube ends with a 37° flare according to DIN 3949 to fitting bodies with a 24° inner cone.

O-rings made from FKM (Viton®) convince with their outstanding media stability over all the commonly used hydraulic media and many other corrosive acids and alkalines. They are suitable for use at temperatures up to +200° C. In view of the combined metallic-elastomer sealing of all the tube fitting types mentioned above, these can also be used unreservedly at low temperatures down to -40° C – as it has been customary to date with NBR (Buna-N®).

The increased UV and ozone stability of FKM (Viton®) enables the maximum permitted storage time of non-installed tube fitting components with pre-stressed O-rings to be extended from 6 to 10 years, conditional upon the storage recommendations as per DIN 7716 are being followed. This effectively prevents any hardening, embrittlement, cracking and resulting leakage risks.

All the benefits at a glance:

  • Significant improvement of media and temperature stability
  • Halving both procurement effort and warehousing given that to date both versions – NBR (Buna-N®) and FKM (Viton®) – have been stocked
  • Increasing the level of UV and ozone stability and lengthening the permitted storage period of non-installed tube fitting components with pre-stressed O-rings
  • Minimizing leakage risks resulting from hardening, embrittlement and cracking of pre-stressed O­-rings

FKM (Viton®) is already the delivery standard for other components of the STAUFF Connect product group that are not directly affected by the change-over, such as Soft-Sealing Cutting Rings (type FI-WDDS) and STAUFF Form Adaptor Rings (type FI-AR).


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