| 摘要 |
1. An annular seal of the double lip type for use with a pressure generator having a cylinder (2), the bore (30) of which is formed with a pressure compensating port (36), and having a piston (4) being formed with a groove (6) adapted to receive the seal (10) ; the seal (10) together with the piston (4) starting from an idle position being first moved by a short distance called dead travel to a position, wherein the pressure compensating port (36) will be closed and being thereafter moved through an extended pressure rise zone corresponding to the active phase ; wherein the exterior lip (14) of the seal (10) has a slightly convex outer profile (20) of revolution ; and wherein the sole (28) of the body (12) of the seal (10) slopes from its largest diameter to its smallest diameter in unstressed condition, characterized in that the seal (10) is arranged in the groove (6) such that the sole (28) of the seal (10) in the idle position and during the dead travel slopes from its largest diameter towards its smallest diameter in such manner that it makes circular contact with the wall (32) of the groove (6) and the sole (28) is in engagement with the wall (32) of the groove (6) throughout its surface during the active phase such that a slight tilting movement of the exterior lip (14) is optained, the exterior lip (14) having such cross-sectional shape that in the idle position and throughout the dead travel a fluid tight contact to the bore (30) of the cylinder (2) is established only along the edge of the end (22) of its exterior surface (20) being remote from the sole (28), and that throughout the active phase the edge of the end (22) is slightly spaced from the bore (30).
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