O-rings: isntallation guidelines

O-ring installation guidelines

General guidelines

O-rings must be laid into purpose-made grooves in order to seal properly.

To avoid damage during installation, the housing groove edges should be canted at an angle of 15 - 20⁰ (see picture below).

It is advisable to use lubricating oil suitable to the type of elastomer.

Make sure there is no dirt or residue left in the housing seat or on the opposite surface being sealed by the O-ring.

Avoid extensive twisting or rolling of the O-rings.

O-rings can be easily damaged by sharp objects, therefore all sharp edges, traces of mechanical processing, threads or drilling should be taken care of prior to installation.

Installation dimensions

For the correct installation of O-rings, it is necessary to be determine the proper installation dimensions depending on the cross section. A selection of these dimensions is shown in the table below. All values are based on the technical guidelines offered in part 5 of DIN 3771. Strictly speaking, the table values only apply to O-rings made of NBR with a standard hardness of 70 Shore A. However, experience shows that this data can be applied to other materials and hardnesses, even though the groove depth may need some adjusting. The values are calculated based on a possible swelling of up to 15%. For materials exhibiting less than 15% swelling, the groove width can be reduced accordingly.

Please note that the values provided in the table are only intended as approximate guidelines. Users are strongly advised to check these values for every specific situation (e. g. by repeated testing). In particular, the contact with the media to be sealed, the temperature at the time of use and the installation conditions may lead to deviations from the values given above.