Seal with pressure relief function

摘要

The sealing has a sealing ring (40a) made of resilient material in contact to a movable machine part (3). A pre-tensioning device (50a) is arranged between a fixed machine part and the sealing ring to exert a bias force on the sealing ring so that the pre-tensioning device is pressed with a normal pressure layer against a low pressure-side groove edge (22) of a groove (20) and against the movable machine part. The pre-tensioning device is not sealed with an inverted pressure layer between a high pressure side (H) and a low pressure side (N). The pre-tensioning device is made of metal and comprises electrical insulating and/or wear reducing coating designed as a metallic spring such as spiral spring or a V-shaped spring.