Negative pressure drilling system to prevent gas overrun

Abstract

The invention relates to a negative pressure drilling system preventing over-limit gas. The negative pressure drilling system comprises a hollow drill rod, a hollow bit, a hydraulic rig, a support, and a drainage system. Both the hollow bit and the hollow drill rod are provided with suction ports. The rear end of the hollow drill rod is connected with a dust suction pipeline through a rotary connector. The dust suction pipeline is connected ith an air inlet of a suction box. An air outlet of the suction box is connected with a suction mechanism. The suction mechanism is connected with an air inlet of an explosion-proof spray dedusting box. An explosion-proof spray air outlet is connected with the drainage system through an exhaust pipe. A sprayer is disposed in the explosion-proof spray dedusting box. The negative pressure drilling system is capable of sucking through a front central hole of the hollow bit and through the suction hole on the side wall of the hollow drill rod, and the suction hole on the side wall of the hollow drill rod discharges most of dust, so that suction and dedusting are improved greatly, dedusting flow is smoother and dedusting is more efficient. The explosion-proof spray dedusting box assists in further dedusting and spray explosion proofing and accordingly the drainage system can operate safely.

Description

technical field [0001] The invention relates to an auxiliary tool for mining coal mines, in particular to a special air suction drill for coal mines. Background technique [0002] Because gas threatens the safety of coal mining, it is an important link before coal mining to pump out the gas in the coal seam from the wall of the underground roadway of the coal mine. For some soft coal seams, only dry drilling can be used, and the compressed air blowing process is used to make the coal powder and compressed air generated during drilling spray out along the gap between the drill pipe and the hole wall. The compressed air used in the dust blowing process has a large impact energy (the impact force is too small to achieve the dust blowing effect), and the formed airflow has a strong impact force, and the dust content is as high as 3000mg / m 3 , leading to a very bad environment on the working face, which seriously threatens the health of the workers. Due to the lax management of...

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Problems solved by technology

At the same time, the gas concentration in the jet stream is high, and there is a danger of coal dust explosion in conditions such as high temperature, static electricity, and open flames.

In order to improve safety production requirements, the huge amount of dust generated by dust blowing must be treated with dust reduction, and fan extraction is prohibited during dust reduction, and dust reduction methods are limited, resulting in poor dust reduction effect

In order to improve the serious environmental pollution problem in dry drilling, the current method is to install a dust collector for the drill pipe casing at the hole of the dry drilling. The small casing goes deep into the coal seam, and the large casing is close to the wall of the roadway. The blowing dust of compressed air is sprayed out along the gap between the sliding drill pipe and the small casing into the large casing, and the dust is sprayed in the large casing to reduce the dust. The dust removal efficiency is between 50% and 60%. Although the dust reduction effect is obvious, it is difficult to achieve Hygienic Standards for Working Environment

Aiming at many problems existing in air-blowing drilling, the publication number is CN102168534A, a kind of exhaust drill, which intends to achieve the purpose of air suction and dust extraction, but there are many problems in this application and cannot be applied and implemented. One of the problems is: The drill pipe is integrated with the driving part, but in actual use, the drill pipe needs to continuously move forward automatically. In the field of coal mining, the drilling depth is tens of meters or even hundreds of meters, and the drill pipe needs to be continuously supplemented and extended to continue to move forward. , in this application, it is necessary to rely on manpower to push the entire driving box and the drill pipe forward together, which is not conducive to the replacement of the drill pipe. It is necessary to repeatedly push the drill pipe driving box during work, and the feasibility is very poor.

The second problem is: because the drill bit will push the dust particles backward during the drilling process, and the strength of the draft is different from that of the blower. When this application is implemented, the draft is limited to the dust particles in front of the hollow drill bit, and there are more holes in the side wall of the drill pipe. The dust particles cannot be pumped away, resulting in the frequent interruption of the drilling work, which cannot be effectively implemented, so that the inventor proposed a new improvement plan

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