| 摘要 |
A fluid-assisted dust seal for a drill shaft includes a tubular housing, flexible seals spaced apart in the housing along its length in contact with a drill shaft therein, a fluid plenum between two adjacent seals in the housing, and a fluid inlet for admitting pressurized fluid into the plenum, to deflect the seals downwardly so as to cause fluid flow out the bottom of the seal and thereby limiting entry of dust into the housing.
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