In mining, tunneling, and geotechnical engineering, down-the-hole drills are core equipment, and their operating efficiency and stability are directly related to project progress and cost control. Rod connection and removal are crucial aspects of down-the-hole drill operations, directly impacting overall work efficiency and the service life of rock drilling tools. The traditional rod connection and unloading method relies on manual operation, which is not only cumbersome and labor-intensive but also easy to cause damage to the rock drilling tools. However, with the rapid development of automation technology, the rod connection and unloading method of down-the-hole drills is undergoing unprecedented changes. The emergence of proportional rod connection and unloading technology, with its high efficiency and intelligent characteristics, leads the down-the-hole drill technology to a new height.
Traditional hydraulic rod connection and unloading process and limitations
Rod connection process
- Preparation stage: first, open the clamps above the rod unloader seat. Then, position the drill rod to be connected to the rod unloader, ensuring that the upper and lower drill rods and the swivel head main shaft are all aligned concentrically with the drill rod to be connected.
- Docking stage: operate the swivel head motor on the guide rail to make a forward rotational motion, and operate the guide rail propulsion cylinder to move so that the swivel head motor slowly moves down to complete the docking of the drill rod and the drill rod, and the drill rod and the motor main shaft.
Unloading process
- Lifting stage: operate the propulsion cylinder to lift the swivel head motor to expose the drill rod to be disassembled from the blast hole until the connection surfaces of the two drill rods can be clamped by the upper and lower clamping cylinders of the rod unloader separately.
- Loosening stage: after clamping the two drill rods, drive the unloading rod cylinder to rotate the upper and lower clamping cylinders relative to each other by a certain angle to loosen the threaded connection between the two drill rods.
- Separation stage: release only the upper clamping cylinder and operate the rotary head motor to reverse the rotation until the threads of the two drill rods are completely disengaged to realize separation.
- Removal stage: operate the upper clamping cylinder, clamp the drill rod to be removed again, reverse the rotary head, loosen the connection thread with the main shaft, push the oil cylinder to lift the rotary head motor to the top of the guide rail, loosen the upper clamping cylinder, and remove the drill rod.
Limitations
- Complex operation: the traditional process of connecting and removing rods requires manual control of the push and turn handles, making the operation steps numerous and complicated.
- High labor intensity: different handles should be operated multiple times during the whole process, which increases the operator’s labor intensity.
- Fragile rock drilling tools: due to the manual operation’s error of manual operation, the push speed is difficult to control accurately, which causes the thread of the rock drilling tools to be damaged due to the rigid transmission force.
- Inefficiency: complex operation steps and uncertainty of manual control affect the operation efficiency.
The rise of proportional connecting and unloading rod technology
With the rapid development of PLC control technology, proportional connecting and unloading rod technology emerged at a historic moment. This technology achieves high automation and intelligence in the rock drilling tool loading and unloading process through the perfect combination of electrical and hydraulic technology. Compared with traditional methods, proportional connecting and unloading rod technology has the following significant advantages:
Improvement of operational efficiency
By precisely controlling the rotational speed and axial displacement of the rock drilling tools, the proportional connecting and unloading rod technology makes the rod handling process smoother and more efficient. The operator only needs to operate a handle to complete complex rod connecting and unloading operations, which reduces time and labor costs.
Reduce labor intensity
With increased automation, operators no longer need to frequently perform complex manual tasks. It reduces their labor intensity and effectively avoids the risk of occupational diseases caused by long-term repetitive work.
Reduce equipment wear and tear
The proportional connecting and unloading rod technology ensures that the threads of the rock drilling tool will not be unnecessarily damaged during the connecting and unloading process by accurately controlling the movement parameters of the drilling tool. It extends the service life of the rock drilling tool and enhances the equipment’s overall reliability.
Improve security
Automated operations reduce the uncertainty and risks caused by manual operations. At the same time, through real-time monitoring and adjustment of the hydraulic system, potential safety hazards can be discovered and eliminated in time to ensure safety during the operation.
The principle of proportional connecting and unloading rod technology
The proportional connecting and unloading rod technology relies on an advanced hydraulic control system and PLC programming control technology. The system uses a dual electro-hydraulic proportional load-sensitive variable pump to provide a power source for the drilling rig propulsion and rotation system. The oil flow is precisely controlled through the proportional directional valve to achieve synchronous adjustment of the rock drilling tool speed and axial displacement.
During the process of connecting and unloading the rod, the operator only needs to set relevant parameters (such as rotation speed and propulsion speed) through the LCD screen on the remote control console, and the system will automatically complete the rod connecting and unloading operation according to the preset parameters. At the same time, the display screen can also display the pressure of the hydraulic system and other critical data in real time, making it convenient for operators to monitor and adjust.
Conclusion
The innovation in rod connection and removal methods for down-the-hole drills is a significant advancement in mining machinery technology. The introduction of proportional connecting and unloading rod technology not only simplifies the complex operating process and reduces the labor intensity of operators but also significantly improves operating efficiency and the service life of rock drilling tools. The application of this technology marks the development of down-the-hole drills in a more intelligent and efficient direction. As technology continues to mature and advance, we have reason to believe that proportional connecting and unloading rod technology will be widely used in more fields and contribute more to the modernization process of mining and geotechnical engineering. At the same time, we also look forward to the emergence of more innovative technologies, injecting new vitality and power into the development of down-the-hole drills and even the entire mining machinery industry.
