seen for the disposal of water out of the borrhal during the core drilling, and device for implementation of the set

摘要

A method for removal of water from drill holes during deep drilling, with use of drilling air conveyed via the tubular drill stem, whereby the drill stem (3) is provided with a number of mutually spaced apart blowing valves (5), which are arranged automatically to open and close said valves in relation to the ratio between the pressure of the drilling air in the drill stem (3) and external forces acting upon a valve body (13) forming part of said blowing valve, whereby said valves (5) are arranged directly in the material of the drill stem (3) or in the material of a separate tube section (6) concentric with the drill stem and having the same outer diameter as the drill stem resp., and which valves are arranged successively in a direction from above and downwards at their positions in the drill stem to emit jets of said drilling air to the space between the drill stem (3) and the wall of the hole for causing the water to be blown up layer by layer from the top and downwards. The valve incorporates a valve body (13), which is axially movable in a through bore (8) in the material (6) of the drill stem between an outer and an inner valve seat (11 and 12 resp.), each such valve being adapted during influence of the drilling air pressure at one hand and the water pressure outside the drill stem on the other hand, to be moved axially in a guide (16) in order automatically to be moved between a position closing the valve against the inner seat (12), an intermediary position opening the valve and a position closing the valve against the outer seat (11) due to the pressure difference between air pressure and liquid pressure.