The role of the drill rod is to send the impactor to the bottom of the hole, transmit torque and shaft pressure, and deliver compressed air to the impactor through its central hole. The drill pipe is subjected to complex loads such as impact vibration, torque, and axial pressure, and is subjected to sandblasting abrasion on the surface of the slag discharged from the hole wall and the drill pipe. Therefore, the drill rod is required to have sufficient strength, rigidity and impact toughness. The drill pipe is generally made of seamless steel pipe with a hollow thick arm. The size of the drill pipe diameter should meet the requirements of slag discharge.
The two ends of the drill rod have connecting threads, one end is connected with the rotary air supply mechanism, and the other end is connected with the impactor. A drill bit is installed at the front end of the impactor. When drilling, the rotary air supply mechanism drives the drill tool to rotate and supplies compressed air to the hollow drill rod. The impactor impacts the drill bit to drill the rock. The compressed air discharges the rock ballast out of the hole. The propulsion mechanism keeps the rotary air supply mechanism and drilling tool forward. Advance.
The size of the drill pipe diameter should meet the requirements for ballast removal. Since the air supply volume is constant, the return air velocity of the discharge of the rock ballast depends on the size of the annular cross-sectional area between the hole wall and the drill pipe. For a hole with a certain diameter, the larger the outer diameter of the drill pipe, the greater the return air velocity.
Post time: Nov-17-2021