| 摘要 |
A valve ( 30 ), a drill string valve assembly ( 10 ) and a method of drilling using compressed fluid as a drill drilling fluid are described. The valve and valve assembly ( 10 ) may be used in order to prevent escape of compressed fluid during the time that a connection is being made into the drill string. The valve ( 10 ) can be insertable into a drill string inner diameter to seal against fluid passage past the body except through the valve ( 30 ) and can be selected to maintain fluid pressure in the drill string when the upper end of the drill string is open to atmosphere. The valve can also be capable of being releasably engaged to a drive mechanism, such as a top drive ( 40 ) which is handling the drill string ( 12 ) to be slidably moved within the drill string, as driven by the drive mechanism, but releasable from the drive mechanism, when the drive mechanism is removed from the drill string.
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