| 摘要 |
<p>A screw drilling device has a rotatable unit (9) which forms a plate (10) having a first axial opening (12) and a cylindrical wall (11) having a first radial opening (19); the unit (9) is mounted on the lower portion (3a) of a central tubular element of the screw and can adopt a boring configuration in which the plate (10) is oriented so as to afford access for debris between the turns of the screw through the axial opening (12) whilst the cylindrical wall (11) is oriented so as to close a second radial opening (4b) formed in the tubular portion (3a) for discharging fluid from the duct (4), and a second, injection configuration in which the plate (10) closes the screw at the bottom and the cylindrical wall (11) is oriented so as to put the first and second radial openings (19, 4b) into communication. <IMAGE></p> |
