Patent ID: 7083170

Claim:
A rod or piston primary seal, comprising: a primary seal ( 2 ) facing space ( 1 ) to be sealed and a secondary seal ( 3 ) facing away from it, in which the primary seal ( 2 ) is fitted into a groove ( 4 ) of a holding element ( 5 ), open in a direction of the relatively movable machine part ( 11 ) which is bounded, on a side facing away from the space ( 1 ) to be sealed, by a first side surface ( 7 ) which extends essentially at right angles to sealing axis ( 6 ), and contains a sealing edge ring ( 8 ) made of tough, hard plastic which has a sealing edge ( 9 ) lying adjacent to the machine part ( 11 ), and is pressed against the machine part ( 11 ) with its sealing edge ( 9 ) by a profile ring ( 10 ), made of elastomeric material, which is supported on the bottom surface ( 12 ) of the groove ( 4 ) and lies adjacent to the sealing edge ring ( 8 ) with its inner surface ( 13 ), wherein the sealing edge ring ( 8 ) has a profile bounded essentially by a right angle between the sealing edge ( 9 ) and a bounding surface ( 14 ) facing the first side surface ( 7 ); and, in a relieved state of the seal ( 2 ), a surface ( 15 ) bounding the sealing edge ( 9 ) on the side facing away from the pressure subtends an angle (β) of at most 8° with the sealing axis ( 6 ); and the sealing edge ring ( 8 ) is penetrated by at least one discharge opening ( 16 ) positioned between the sealing edge ( 9 ) and the outer surface of the sealing edge ring ( 8 ) and opens out onto the bounding surface ( 14 ) wherein the discharge opening directly contacts the bounding surface and the discharge opening directly contacts the first side surface during a pressure difference between a higher pressure side and a lower pressure side of the primary seal, the higher pressure side facing space ( 1 ) to be sealed.