Drill stem with internal powder discharging function

Abstract

The invention discloses a drill stem with an internal powder discharging function. The drill stem comprises a front segment, a rear segment and a drill bit, wherein the drill stem is hollow, a tapered internal thread is arranged at the head part of the front segment of the drill stem, a tapered external thread is arranged at the tail part of the front segment of the drill stem, nozzles are uniformly arranged in a center hole of the front segment of the drill stem, and the nozzles are inclined and are mounted corresponding to water holes formed in the drill stem; the rear segment of the drill stem comprise a plurality of short rods adopting the same structure, a tapered internal thread is arranged at the head part of each short rod, a tapered external thread is arranged at the tail part of each short rod, the short rods are connected with one another through the tapered threads, a sealing ring is arranged at the joint of every two adjacent short rods, and water holes are formed in the short rods, and communicate with those in the front segment of the drill stem; and the front segment of the drill stem is connected with the drill bit, the drill bit is shaped like a stepped taper, the water holes are just aligned after the front segment of the drill stem is fastened with the short rods of the rear segment of the drill stem, and high-pressure water is introduced into the end parts of the water holes of the rear segment of the drill stem. Through adoption of the drill stem with the internal powder discharging function, provided by the invention, the hole-forming rate can be improved, the hole-forming shape can be kept, and the incidence of such accidents as hole collapse and drill wedging can be reduced in a drilling process.

Description

technical field [0001] The invention relates to an internal powder-discharging drill pipe, which belongs to the field of drilling equipment for soft coal seams. Background technique [0002] Underground gas drainage in coal mines is mainly realized by drilling holes with coal seam horizontal drilling rigs. Soft outburst coal seams (hardness coefficient ≤ 1) have poor permeability and high gas content. During the drilling process, it is easy to produce collapsed holes, drill sticking, spray holes and other phenomena. Although there are records of drilling depths exceeding 150m in soft coal seams in my country, most of the drilling depths are below 100m, and the hole formation rate is low, and the cost of outburst prevention and gas drainage is high. In my country, soft coal seams account for a relatively large proportion of coal seams mined, so the problem of drilling holes in soft coal seams has always been a difficult problem that needs to be solved urgently. [0003] Wh...

AI Technical Summary

Problems solved by technology

At this time, if the drilling rig continues to give pressure, it will cause the rock dust to stay in the hole, which will lead to the cutting and powder discharge forms of accumulation and blockage of rock.

However, due to the special geological conditions and the soft texture of the coal seam, it is still very difficult to drill, especially the construction rate of advanced drilling is very low.

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