| 摘要 |
The mechanical seal for sealing off the shaft (2) of a rotary machine is used where the pressure difference between the inner fluid (10) acting on the seal and an outer fluid (11) varies from positive to negative or vice versa. In this arrangement, an axially non-displaceable ring (4) and a seat ring (3) secured on the shaft are provided with interacting sealing surfaces (5) which form a seal between the outer fluid and inner fluid situated respectively outside and inside a holder (6). The holder is axially movable but cannot be rotated about the shaft and is preloaded against the seat ring by means of a preloading spring (7) if the pressure of the outer fluid is higher than the pressure of the inner fluid. The holder is situated in a housing (1) and can likewise move axially but is non-rotatable. Such a seal ensures reliable sealing even when the pressure of the outer fluid exceeds the pressure of the inner fluid. It is used, in particular, in pumps and compressors. <IMAGE>
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