| 摘要 |
A sealing device affording a moderate leakage for the passage of a rotary shaft extending through the wall of a casing in which the internal fluid pressure differs from the external pressure, this device comprising in combination a tubular socket surrounding said rotary shaft, the inner surface of said socket having a small annular clearance with respect to the outer surface of said rotary shaft, so that these two surfaces provide therebetween an annular passage permitting a limited fluid flow between said casing and the surrounding atmosphere. At least one of the two registering cylindrical surfaces, namely the inner surface of said socket and the outer surface of the corresponding portion of said shaft, is provided with a lining of a material having a low coefficient of friction. A bellows-forming sleeve of flexible material connects said socket to the wall of said casing through which said rotary shaft extends and said socket is restrained against movement in longitudinal direction.
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