Large-pitch special-shaped spiral drill rod

Abstract

The invention relates to a large-pitch special-shaped helical drill rod, which includes a drill rod body provided with a medium conveying channel inside. The two ends of the drill rod body are respectively provided with external threads and internal threads. Composed of arc segments, the straight segment and the arc segment are arranged at intervals, the head and tail are connected with each other and the number is equal, the arc segment is not less than two, the outer wall of the drill rod is provided with a spiral groove, the A helical blade is arranged in the helical groove. The purpose of the present invention is to increase the slag discharge capacity by setting the spiral blade in the spiral groove on the outer wall of the drill pipe, and prevent the coal dust from being blocked in the gap between the drill pipe and the coal wall to cause gas accumulation, difficult drilling, and even drill sticking , Drill drop and other accidents in the hole, improve the hole formation rate and drilling efficiency; by nitriding, high-frequency quenching, phosphating or nickel-phosphorus treatment on the internal and external threads of the drill pipe body, avoid The internal and external threads are bonded together, which makes the removal of the drill pipe easier.

Description

technical field [0001] The invention belongs to the technical field of underground gas drainage drilling in coal mines, and relates to a special-shaped helical drill rod with a large pitch. Background technique [0002] The problem of drilling in broken and soft coal seams has always been a difficult problem in the drilling construction of coal seam gas drainage in mines at home and abroad, especially in soft and outburst mines with high ground stress and high gas. The rod has been unable to meet the construction requirements of the gas drainage hole. At present, in the mining and utilization process of soft and outburst coal seams, drilling rigs and negative pressure suction are still used for gas control, and ordinary auger drill pipes or triangular drill pipes are mostly used as drill pipes. Among them, the blades of ordinary auger pipes are relatively high, and there are more coal chips in the broken soft coal seam, which causes the friction force of the coal chips on t...

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Problems solved by technology

[0002] The problem of drilling in broken and soft coal seams has always been a difficult problem in the drilling construction of coal seam gas drainage in mines at home and abroad, especially in soft and outburst mines with high ground stress and high gas. The rod can no longer meet the construction requirements of the gas drainage hole

Among them, the blades of ordinary auger pipes are relatively high, and there are more coal chips in the broken soft coal seam, which causes the friction force of the coal chips on the helical blades and the drill pipe body to be relatively large, so it is easy to cause slag discharge and blockage during the drilling process In some cases, when the friction torque of coal cuttings on the drill pipe exceeds the rated torque of the drilling rig, accidents such as drill sticking, drilling or even drill drop will occur; the slag discharge of the triangular drill pipe is better than that of the ordinary helical drill pipe, because its The special cross-sectional shape of the drill pipe provides more discharge space for the coal dust, and because the outer surface of the drill pipe is prism-shaped, the prism can prevent the coal dust from settling, but there is no power to transport the coal dust out of the hole. The compressed air is blown out of the hole, so the drilling depth is greatly restricted, and there is a great potential safety hazard

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