Hollow-out inner cutting discharge alloy drill bit

Abstract

The invention belongs to the coal mine gas extraction technical field and relates to a hollow-out inner cutting discharge alloy drill bit for underground coal mine gas extraction drilling construction. The hollow-out inner cutting discharge alloy drill bit comprises a drill bit matrix, a main alloy sheet group, an auxiliary alloy sheet group, lateral side alloy sheet groups, lateral side main flow guide grooves, lateral side auxiliary flow guide grooves, a front portion flow guide groove, a drill bit hollow-out inner chamber, a flow guide opening and drill bit internal threads; the front end of the drill bit is formed by the main alloy sheet group, the auxiliary alloy sheet group and the front portion flow guide groove and is of a hollow-out structure with the hollow middle; the lateral side main flow guide grooves, the lateral side auxiliary flow guide grooves, the front portion flow guide groove, the flow guide opening and the drill bit hollow-out inner chamber form a discharge channel of the gas and drilling cuttings. According to the hollow-out inner cutting discharge alloy drill bit, the current cutting discharge way is changed, the negative pressure air is utilized as a fluid medium, the outer drilling cutting discharge is changed into the inner discharge to enable the drilling cuttings to be discharged from the inside of a closed drill pipe, and accordingly the dust-free construction is implemented and the fixed-point sampling can be performed at any time during drilling construction; the ultra-limit prevention and blowout prevention effect is achieved; the significant innovation is brought to the gas treatment process.

Description

technical field [0001] The invention relates to the technical field of underground gas drainage in coal mines, in particular to an alloy drill bit for removing chips in hollowed-out drilling holes for construction of underground gas drainage in coal mines. Background technique [0002] At present, the gas control technology mainly adopts coal seam pre-extraction of gas, and the construction of gas extraction boreholes is the key link of gas control. The hardness coefficient of the coal seams mined in high gas outburst mines is mostly below 0.5, especially the third soft coal seam affected by sliding structure, the hardness coefficient is less than 0.3. The construction method of the existing gas drainage drilling is to adopt the outer chip removal type drill bit to cooperate with the triangular arc drill pipe to drill, and the compressed air to remove the chips. This construction method has a lot of debris and dust, which affects the working environment; a large amount of c...

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Problems solved by technology

This construction method has a lot of debris and dust, which affects the working environment; a large amount of coal debris remains in the borehole, which affects the drainage effect; the triangular arc drill pipe impacts and damages the hole wall during the rotation process, resulting in low construction hole formation rate; prior art The source of drilling cuttings cannot be determined during drilling and sampling, and fixed-point sampling cannot be realized, which reduces the reliability of the evaluation report; the gas gushing out during the construction process is difficult to control, resulting in gas injection holes, over-limit

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