In the 21st century, the world economy is developing rapidly, and science strength continues to strengthen. It has directly promoted the rapid development of railways, highways, hydropower, and other industries. With the development of these industries, the amount of geotechnical engineering during construction began to increase, which promoted the development of rock drilling equipment.
Because of the superiority of hydraulic rock drills in terms of technical performance and perforation efficiency, companies in various countries have set off the climax of developing hydraulic rock drills and related equipment. After decades of development, hydraulic rock drills have formed different model series with hundreds of specifications and are used in many fields such as mining, hydropower, and tunnel traffic. With the development of hydraulic rock drilling rigs, hydraulic rock drills have a broader use space, especially in large-scale rock excavation projects such as large-scale hydropower and mines.
What is a hydraulic rock drill?
The hydraulic rock drill is a new type of rock drilling machine powered by hydraulic pressure. Through the oil distribution mechanism, the high-pressure oil acts alternately on both ends of the piston and forms a pressure difference, forcing the piston to make reciprocating movement in the cylinder to complete the function of impacting the brazier to break the rock.
It has the advantages of stable performance, unique structure, small size, lightweight, fast drilling speed, low vibration, low noise, low energy consumption, and low operating intensity of personnel.
Its basis is in two types: a hand-held rock drill and a large airborne rock drill.
1. Small hand-held rock drill: its impact energy is small, it is mainly used to replace traditional air picks, and most of them are used in conjunction with loaders and hydraulic engineering vehicles during small excavation;
2. Large airborne rock drill: Most of these hydraulic rock drills are based on the backhoe operation device of the hydraulic excavator, and the backhoe bucket is replaced with a rock drill for work, and the excavator driver operates in the cab. The energy of this type of rock drill is high.
Features of hydraulic rock drill
- Efficiency: the hydraulic rock drill uses high-pressure oil to transmit pressure, consumes less power, has high energy utilization, and has a high rock drilling speed, thus improving work efficiency.
- Flexibility: hydraulic rock drills are compact and lightweight, making them easy to transport and install. At the same time, its control valve is reasonably designed, convenient to operate, and easy to master.
- Safety: the hydraulic rock drill has an overload protection function to ensure that the equipment can automatically shut down under abnormal circumstances to avoid equipment damage and casualties.
- Adaptability: hydraulic rock drills are suitable for rock drilling operations with various rock hardnesses, including soft rock, medium hard rock, and hard rock. By adjusting the pressure and flow of the hydraulic system, it can adapt to different rock drilling needs.
- Environmental protection: hydraulic rock drills use hydraulic oil as the power medium. Compared with traditional pneumatic rock drills, they reduce noise and dust pollution and are more environmentally friendly.
Structure of hydraulic rock drill
The hydraulic rock drill mainly consisted of an impact mechanism, a rotary mechanism, a water supply and powder discharge device, and a dust-proof system. Its rock drilling operation integrates the functions of impact, rotation, propulsion, and rock hole flushing. These structures have their characteristics. For example, there are those with or without stroke adjustment devices, some with a central water supply, and some with a side water supply. There are cylinder liners with or without cylinder liners in the cylinder. To prevent the drill rod from being stuck in the rock hole and cannot be pulled out during deep-hole rock drilling, several hydraulic rock drills are equipped with a backflush device in front of the water supply unit.
Working principle of hydraulic rock drill
The working principle of hydraulic rock drill is based on Pascal and the hydraulic impact principle. Specifically:
Pascal’s principle: hydraulic rock drills use pressure changes in the hydraulic system to achieve piston movement. In this system, the valve controls the reciprocating motion of the piston, allowing the piston to move back and forth in the cylinder.
Principle of hydraulic impact: during the impact process, the piston is motivated by high-pressure oil and moves toward the shank adapter direction at a certain speed. When the piston reaches the predetermined position, it will open the stroke reversal signal orifice so that the high-pressure oil will act on the flow distribution valve core through the push valve oil circuit so that it will move to the right and complete the stroke reversal. Subsequently, the piston immediately switches to the return motion, also driven by high-pressure oil, and the flow distribution valve core moves to the left to prepare for the next cycle.
During this process, the high-frequency reciprocating motion of the piston continuously impacts the shank adapter, causing the rock to be crushed and dug into the hole. As the piston retracts, the shank adapter will turn to a certain angle so that it can impact the drill tail again and form a new dent. This action is repeated several times, resulting in a circular drill hole with a certain depth.
Types of hydraulic rock drills
The hydraulic rock drills that entered the market in the 20th century had rail type, outrigger type, and hand-held type. Due to the weight limitation, the output power of the outrigger and hand-held hydraulic rock drill is almost the same as that of a pneumatic rock drill at the same level, ecause the drilling speed and other reasons can not reflect the superiority of hydraulic rock drill, the development is not fast. Therefore, the general hydraulic rock drills we mentioned belong to the rail-type hydraulic rock drills.
Application scenarios of hydraulic rock drills
Different grades of hydraulic rock drills have different machine weights, technical performances such as impact power and torque, and different applications.
In short, there are generally two categories:
1. Engineering: earthwork engineering, removal engineering, road and bridge engineering, tunnel excavation engineering, (non-) excavation engineering, water conservancy engineering, etc.
2. Mining: stone mining (marble, granite, sandstone, limestone, etc.), metal mining, coal mining, sandstone mining, etc.
Development of Hydraulic Rock Drills
The hydraulic rock drill originated in the early 1970s. In 1970, the French Montabert Company developed the world’s first hydraulic rock drill H50, which was mounted on a hydraulic drilling rig for mine drilling. Then there was the American Ingersoll-Rand Company, Gardner-Denver Company, Atlas Copco Company of Sweden, Linden-Almak Company, Tamock Company of Finland, Emco-Secoma Company of France, Krupp Company of Germany and FU RU KAWA Company of Japan invested in the development of hydraulic rock drills and related supporting drilling rigs. Among them, the hydraulic rock drills and related drilling rigs produced by AtlasCopco of Sweden and Tamock of Finland are the most representative, accounting for more than 60% of the market share. Whether it is underground or open-pit excavation or mining, there are corresponding hydraulic rock drills for selection. For example, in Tamock of Finland in the early 1980s, the company only had three series of hydraulic rock drills, and then gradually developed more series of products, ranging from small hand-held to super-heavy, with complete varieties and specifications.
While developing rotary-impact products, pure rotary hydraulic rock drills for drilling on soft rocks have also been developed accordingly. In particular, Atlas Copco of Sweden can flexibly assemble products for special purposes with a slight improvement on some base-type products according to some special requirements of users. The mating parts can be changed with different environments in different areas. In the development of light products, plastic parts are used in large quantities to reduce the weight of the whole machine. The shell of the hydraulic rock drill is mostly made of precision casting, which makes the structure of the machine compact, the layout reasonable and the appearance more beautiful.
With the continuous advancement of science and technology and the continuous improvement of engineering needs, hydraulic rock drills are also constantly developing and innovating. In the future, the development trend of hydraulic rock drills will primarily focus on the following aspects:
- Intelligence: intelligence is an essential direction for the future development of hydraulic rock drills. The future of hydraulic rock drills will likely involve integrating intelligent control systems and sensor technology to enable remote monitoring and automated control. This advancement aims to enhance equipment efficiency and safety during operation.
- High efficiency and energy saving: as environmental awareness grows, the development of hydraulic rock drills is increasingly focused on high efficiency and energy conservation. Through the optimization of hydraulic systems and transmission mechanism design, energy consumption and emissions of equipment are minimized, leading to the adoption of greener and low-carbon production methods.
- Modular design: modular design helps improve the versatility and maintainability of hydraulic rock drills. By decomposing the equipment into multiple independent modules, it is convenient to disassemble, repair, and replace the equipment, reduce maintenance costs, and increase the service life of the equipment.
- Multi-function integration: multi-function integration is another trend in the future development of hydraulic rock drills. By integrating various functional modules into a single piece of equipment, it can realize the multi-purpose of various rock drilling operations and improve the adaptability and flexibility of the equipment.
In conclusion
Hydraulic rock drills have not been on the market for a long time. However, its research, development, manufacture, and application are inseparable from the joint efforts of all regions of the world, which are inseparable from the need for efficient rock drilling equipment in the development of nature. After all, taking advantage of efficient and economical hydraulic rock drilling opportunities can increase people’s work efficiency. Of course, with changes in the ecological environment, people may face more construction problems in rock drilling. It requires that the development of hydraulic rock drills needs constantly adapt to new needs, combined with the development of science and technology to continuously improve the technical performance to adapt to different objective conditions. It is bound to make the hydraulic rock drill a broader space for future development.
