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The Composition and Working Principle of The Hydraulic Rock Splitter
The main contents are: the fracture characteristics of stone; the structure and working principle of hydraulic splitter; the hydraulic system and control of splitter; the correct operation of hydraulic splitter.
The hydraulic splitter is a device that uses the common physical tipping principle and the hydraulic transmission principle to change the axial hydraulic thrust into the lateral splitting force. China is a country with abundant stone resources. Mining stone often encounters the problem of secondary disintegration when it encounters large blocks. The current secondary disintegration methods mainly include: manual hammer crushing method, drilling and expansion cement bursting method, explosive secondary blasting method, excavator plus hydraulic hammer impact crushing method. These methods have certain shortcomings. The first two methods are very inefficient. Although the fourth method is more efficient, it is difficult for SMEs to accept due to the high cost of equipment. At present, it is more common to use explosives for secondary disintegration. For the secondary blasting of large rocks, the danger is great. First, there are frequent personal injury and death accidents; secondly, due to the large number of explosives, fuses and detonators circulating and used in the civil society every year, the management is very difficult. It will bring hidden dangers to people's lives and property safety and social security; at the same time, there are problems such as environmental pollution and waste of resources. Therefore, some mines simply do not allow the use of explosives for secondary blasting. Exploring a safe, efficient, easy to operate, low-cost secondary disintegration method has always been a hot topic in the industry. The emergence of hydraulic splitters solves this problem. The use of hydraulic splitting machine for the secondary disintegration of large blocks has the advantages of high efficiency, low cost, simple operation, safety and reliability, and has good effect. It is an ideal secondary disintegration device. This paper briefly introduces the structure, working principle and operation method of the hydraulic splitter.
1. The Fracture Characteristics of Stone
Understanding the fracture characteristics of stone is the basis for mastering the splitting principle of hydraulic splitters and the proper design and use of equipment. The stress-strain curve for most rocks, approximate to a straight line, is shown in Figure 1-a and can be represented by F. Where: ε is the stress of the rock; δ is the strain of the rock; E is the Young's modulus of the rock. This line is broken by sudden breakage of the rock and terminates at point F, which is characterized by typical brittle failure.
The full stress-strain curve of rock used as building material, see Figure 1-b, although it is different, can be roughly divided into four sections: OA, AB, BC and CD. In the OA and AB sections, the stress and strain are close to elastic and accompanied by slight hysteresis. When loading or unloading, the structure and properties of the rock are irreversible. In the BC section, the slope of the stress-strain curve increases with stress. And gradually reduced to zero, when loading or unloading, although the rock will produce irreversible changes, that is, permanent deformation, but also does not lose the ability to resist the applied load, so the rock is in a ductile state in this segment; in the CD segment, rock resistance The capacity of the load decreases with the increase of the deformation. The stress gradually decreases from the maximum value of the C point, showing a negative stress-strain curve slope, but eventually terminates at the point D due to sudden fracture failure, and still exhibits the characteristics of brittle failure. .
Irregular longitudinal cracks occur under uniaxial compression of rock. The rupture is partly due to shear rupture and the other part is tensile rupture. That is, when the indenter invades the rock, shear fracture occurs at the contact, and radial tensile stress is caused at the edge thereof, resulting in longitudinal splitting of the brittle rock.
2 hydraulic strainer structure and working principle
2.1 Splitting principle of hydraulic splitter
Figure 2 shows the structure and working principle of the GD series hydraulic splitter. The machine is composed of a power supply system (pump station), a control element, a hydraulic line, a hydraulic cylinder, a wedge assembly, and the like. During operation, the pump supplies high-pressure oil to the system, enters the rodless cavity of the hydraulic cylinder through the control component and the hydraulic pipeline, pushes the piston to move downward, and converts the longitudinal thrust into the lateral splitting force by the amplification of the wedge assembly. To separate the ore.
Figure 3 is a force diagram of the cusp splitter and the cusps and wedges. As shown in Figure 3-a, the sharp point associated with the piston of the hydraulic splitter does not directly split the rock, but has a pair of wedges on both sides of the tip, that is, the two wedges sandwich the tip to form a 40mm A cylindrical splitter. Drill a number of 40mm holes in advance on the predetermined rock split line, and then insert the splitter into the holes respectively. When the hydraulic splitter passes the high-pressure oil, the splitting force can be generated simultaneously in the hole, causing the rock to press. The predetermined position and direction are split.
When the wedge-shaped indenter is pressed and invades the rock, the rock locally pulverizes or plastically deforms to form a pocket or a spherical core, which is usually called a dense core. During the pressing of the indenter, the intrusive depth does not increase in equilibrium with the increase of the load, but when it reaches a certain critical value, the levitating phenomenon occurs. At this time, the rock on the side of the compact core collapsed, the load temporarily fell, and the indenter continued to invade to a new depth.
The load rises again, and the invading and the load return to a certain proportional relationship. This cycle until the rock breaks. The load of the whole process is in a wave shape. The more brittle the rock, the more obvious the characteristics of the leap-forward intrusion, and the plastic material is more moderate. The slope of each rising section of the load-invasion curve is approximately the same, that is, the increase of the unit load is increased by the near-constant. The condition of the falling part of the curve is related to the rigidity of the rock and the loading mechanism.