| 摘要 |
<p>A device and the relative procedure are described, for the insertion of a new drilling string-element into a drilling-string essentially consisting of a short pipe-shaped body (C) having, at its ends, means suitable for screwing it onto drill pipes, in which two valves are housed, of which one (A) is radial to said short body, interceptable from the outside by means of an adaptor and equipped with a suitable safety plug, the other (B) axial to said body.</p> |
