Spiral convex rib cutting hole pressure relief internal slag discharge drill pipe

Abstract

The invention discloses an internal slag discharging drill rod provided with spiral convex ribs for cutting and holes for pressure relief. The internal slag discharging drill rod comprises a hollow rod body, a flow injecting pipe coaxially arranged in the rod body, and a supporting piece for connecting the rod body with the flow injecting pipe. A slag discharging channel is formed between the inner wall of the rod body and the outer wall of the flow injecting pipe; an air inlet and water inlet channel is formed in the flow injecting pipe; with the direction opposite to the rotating direction of the drill rod body during drilling as the reverse direction, the spiral convex ribs ascending in a cylindrical spiral shape in the reverse direction are arranged on the outer cylindrical face of therod body; and the multiple pressure relief holes are formed in the outer cylindrical face of the rod body along one sides of the spiral convex ribs. If hole collapse occurs during drilling, coal slagcan enter the slag discharging channel through the pressure relief holes, the acting force of the coal slag on the drill rod is released, meanwhile, the spiral convex ribs have the hole raking capability, and thus the coal slag is in a loose state and enters the slag discharging channel through the pressure relief holes till the hole collapse area is smooth.

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 convex rib cutting hole for pressure relief and internal slag discharge drill pipe suitable for drilling in high-stress coal seams. Background technique [0002] The gas control of most mines in China mainly relies on underground gas drainage. With the continuous increase of mining depth, the problem of gas drainage faced by high-stress coal seam mining has been paid more and more attention. Under high stress conditions, the deformation of the borehole is large and the deformation speed is fast. During the drilling process, the phenomenon of drill sticking and drill breakage is prone to occur. [0003] At present, there are two kinds of drill pipes commonly used in high-stress coal seam drilling in China: one is the helical (rib, blade) drill pipe based on the principle of mechanical and wind double slag discharge and heat dissipat...

AI Technical Summary

Problems solved by technology

Under high stress conditions, the deformation of the drilled hole is large and the deformation speed is fast. During the drilling process, the phenomenon of drill sticking and drill breakage is easy to occur

[0003] At present, there are two kinds of drill pipes commonly used in high-stress coal seam drilling in China: one is the helical (rib, blade) drill pipe based on the principle of mechanical and wind double slag discharge and heat dissipation; the other is based on eddy current loosening and wind force Due to the small rotation radius of the triangular drill pipe for slag discharge, the auger drill pipe cannot effectively cut the coal body that creeps and shrinks or protrudes from the hole wall.

The triangular drill pipe uses the principle of eddy current to form a slagging channel, and the slagging effect is very good when using the wind slagging method, but the slagging effect is not ideal when the hydraulic slagging method is used.

[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 protruding coal body of the hole wall, and it is easy to get stuck and stuck; there are too many pressure relief holes, the strength of the drill pipe is low, and it is easy to break the drill ;The setting of the pressure relief hole is unreasonable. During the rotation of the drill pipe, there is a pressure relief blind area, which is prone to drill sticking

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