DTH impactor is an integral part of DTH drilling rig and belongs to the working device of DTH rig. DTH impactors are divided into low wind pressure DTH impactor, medium pressure DTH impactor and high wind pressure DTH impactor.
It is widely used in the mine where metallurgy, coal, chemical industry and building materials are not busy, as well as water conservancy, hydropower, highway, railway, construction and other projects. It is suitable for dry type, wind water mixing and water gushing from blast hole. It has reliable working performance and is an ideal drilling and blasting hole equipment.
Working principle of the impactor: at the beginning of the impact stroke, the piston and the valve plate are in the extreme position. The compressed air enters the upper chamber of the cylinder through the radial holes of the valve cover and valve seat, and pushes the piston to move downward at high speed to impact the drill bit. When the spline groove from the piston to the bushing is closed, the pressure in the lower chamber begins to rise, so the central hole at the upper end of the piston leaves the valve rod, so that the upper chamber is ventilated with air, the pressure is reduced and the working stroke is finished. When the piston impacts the bit tail, the valve plate reverses due to the pressure difference between up and down, and the piston repeatedly returns to the stroke.
DTH impactor, like pneumatic percussion drill, belongs to rock drilling tools and has a wide range of uses. The following describes the use and maintenance of DTH impactor.
1. Since the joint and joint of the impactor are all right-hand threads, the right-hand rotation of the impactor should always be maintained during drilling.
2. When drilling, the DTH impactor should use a small impact and propulsion force to make the bit enter the rock stratum smoothly.
3. It is very important to match the propulsive force with the weight of the drilling tool, and the thrust of the propeller must change with the weight of the drilling tool.
4. The rotary speed of DTH impactor is usually 15-25rpm. The faster the speed is, the faster the drilling speed will be. However, in hard rock, the rotational speed should be reduced to ensure that the bit will not be excessively worn.
5. Because the block and cavity may cause sticking, the percussion device should be used to blow hard and the bottom of the hole should be cleaned regularly.
6. In the process of rod extension, rock debris and various impurities will fall into the DTH impactor. Therefore, the end of the loose drill pipe thread must be covered to ensure that the drill pipe does not stick to rock debris and dust.
7. The reasonable lubrication of impactor can never be ignored, otherwise, it will accelerate the wear of impactor and even cause damage.
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