A hole protection drill pipe for pressure relief and internal slag discharge

Abstract

The invention discloses a drill rod with functions of hole protecting, pressure relief and internal slag discharging. The drill rod comprises hollow rod bodies, flow injecting pipes coaxially arrangedin the rod bodies, and supporting pieces connecting the rod bodies with the flow injecting pipes; slag discharging channels are formed between the inner walls of the rod bodies and the outer walls ofthe flow injecting pipes; the flow injecting pipes are internally provided with air inlet and water inlet channels; and with the direction opposite to the rotating direction during drilling of the drill rod bodies as the reverse direction, the outer cylindrical surfaces of the rod bodies are provided with spiral grooves rising in the reverse direction and in cylindrical spiral shapes, and a plurality of pressure relief holes communicating with inner cavities in the rod bodies are formed in the spiral grooves. During drilling of a soft coal seam and an outburst coal seam, the drill rod has theadvantages that the hole protecting ability is high, the slag discharging channels are not prone to being plugged, the hole forming effect is good, the slag discharging and temperature reducing abilities are high, and the hole collapse area is automatically dredged.

Description

technical field [0001] The invention belongs to the technical field of gas drainage drilling in coal mines, and in particular relates to a spiral groove protection hole pressure relief internal slag discharge drill pipe suitable for gas drainage drilling in soft coal seams and outburst coal seams. Background technique [0002] Drilling in soft coal seams and outburst coal seams has problems such as difficult slag removal, low drilling efficiency, shallow drilling depth, low hole formation rate, and poor hole formation effect, which directly affect the quality of drilling hole sealing and gas drainage efficiency. [0003] At present, in the drilling of soft and outburst coal seams in China, the commonly used drill pipes are spiral (low spiral) drill pipes and triangular drill pipes. Since the diameter of the helical grooved drill pipe is much smaller than the diameter of the drilled hole, the drill pipe does not have the ability to protect the hole, causing the coal mass on t...

AI Technical Summary

Problems solved by technology

Since the diameter of the helical grooved drill pipe is much smaller than the diameter of the drilled hole, the drill pipe does not have the ability to protect the hole, resulting in instability and deformation of the coal mass on the hole wall or even hole collapse; The rotation diameter of the triangular drill pipe is close to the drilling diameter, but the contact area is small and the hole protection ability is weak. When the triangular drill pipe uses hydraulic slag discharge, the slag discharge effect is not ideal

Moreover, the slag discharge channels of the above two kinds of drill pipes are located between the outer wall of the drill pipe and the hole wall, the shrinkage of the hole diameter or the collapse of the hole has a great influence on the cross section of the slag discharge channel, and the phenomenon of drill sticking is prone to occur during the drilling process

[0004] The published Chinese patent invention "dual-channel porous turbulent flow pressure relief drilling tool for soft coal rock drilling", the patent publication number is: CN203584298U, uses a dual-channel porous turbulent flow pressure relief drill pipe to protect holes and protect slag discharge The channel has a good effect, but the drill pipe does not have the ability to cut the coal protruding from the hole wall, and it is prone to drill sticking and sticking; the number of pressure relief holes is too large, the strength of the drill pipe is low, and the drill pipe is prone to breakage

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