Don B. Robertson

Summary of Detailed Steps for Knowledge Popularization and Daily Storage of Down-the-Hole Drilling Tools

Original Title: Summary of Detailed Steps for Knowledge Popularization and Daily Preservation of Down-the-Hole Drilling Tools Size selection of down-the-hole impactor, drill bit and drill pipe The size of the down-the-hole impactor depends mainly on the hole diameter and the rock type. For blasting holes, the hole diameter range of down-the-hole drilling is from 89mm to 252mm, the hole diameter less than 89mm is mainly the top hammer type, and the multi-purpose rotary drilling mode with a hole diameter greater than 252mm is mainly selected. Generally speaking, the smallest hole size that a down-the-hole impactor can fit is its nominal size, which means that the smallest hole size that a 4-inch impactor can fit is the 4-inch hole size. Generally speaking, in this case, there is enough annular space between the impactor and the hole wall, and between the drill pipe and the hole wall for slag discharge. The maximum size of the matching bit is the size of the impactor plus 1 inch. For example, the maximum bit size to match a 4-inch impactor is 5 inches. The outer diameter of the drill pipe and the outer diameter of the impactor are as close as possible, which can ensure better slag discharge and reduce the possibility of sticking. In terms of the processing technology of drill pipe, the surface finish and dimensional accuracy of cold-drawn pipe are superior to those of hot-rolled pipe. Good surface finish means that the surface of the steel pipe is not prone to peeling, and the metal chips caused by peeling will reduce the service life of the impactor. In addition, if the connection part of the thread of the drill pipe and the main body is welded by friction, the strength of the drill pipe can be increased, and meanwhile, if the heat treatment of the thread part is well done, the reliability and strength of the thread can be increased, so that the connecting and disconnecting rod is smoother, and the working efficiency and the total perforation speed are improved. Select the appropriate down-the-hole bit Looking at the drill bit, the main body of the drill bit is usually machined from cemented carbide, then heat treated to the specified hardness, so that the surface compressive stress has enough fatigue resistance,Tapered Rock Bit, and then embedded with cemented carbide drill teeth. The convex, sharp-tooth bit design provides the fastest drilling efficiency and is most suitable for medium-soft rocks with low grindability. For hard rock with high grindability, the flat drill bit can improve the life of the drill bit. If the outer edge of the button is large enough, the life of the drill bit can be improved and the use cost can be reduced by grinding the drill bit for many times. In addition, the concave button bit can also be applied to such hard rock with high grindability. Expand the full text As shown in the figure below, the concave drill bit is more suitable for medium hard rock with developed joints and many fissures, which can effectively reduce the probability of hole deviation, which is also mentioned in the previous article series. Practical application Drills in open pit mines and quarries usually require relatively durable down-the-hole impactors, because quarries are usually long-term operations,Mining Drilling Equipment, and it is not cost-effective to replace impactors frequently. Some of the better down-the-hole impactors can be repaired and used many times before they are completely replaced, such as changing the direction of the outer tube of the impactor. The straightness of the hole is more important for the drilling of building stone (marble, etc.). In the drilling of holes larger than 89mm, the straightness of the down-the-hole type is usually better than that of the top-hammer type. Exploration drilling needs to be carried out in remote sites with poor facilities. Therefore, the requirements of Dth impactor are simple design, high reliability, and to adapt to high wind pressure drilling. Reverse circulation percussion drilling is also commonly used, and this sampling method is relatively cost-effective for diamond core drilling. The reverse circulation impactor uses the same process as the common down-the-hole impactor, but the reverse circulation drill pipe is used. High-pressure air is blown through the gap between the inner wall and the outer wall of the drill pipe, and then the cuttings are discharged from the inner wall of the drill pipe, and then the cuttings are collected with a dust bag, as shown in the following figure. In actual use, there is always an important factor to consider, that is, the rig operator. An experienced driller can effectively adjust the drilling parameters to reduce the probability of impactor failure and improve the life of the impactor. There are a variety of impactor options on the market, both inexpensive and high-end. However, the value of impactor is not only measured by its material and design itself, mining dth bit ,dth button bits, but also by the balance between the efficiency brought to users and the cost of rock and rice. For example, an impactor is very cheap and durable, but the fuel consumption is very high, the result is that the cost of rock rice is very high, which can not be said to be a good impactor. Another impactor is very expensive, but the efficiency is also high, and the cost per rock meter is low, so this is a good impactor.
Of course, as a user, we also need to consider whether the impactor manufacturer can provide sufficient technical support and use guidance, which is also very important, and can effectively help our users improve drilling efficiency and reduce the use cost. Preservation of drill pipe First, blow to remove the water inside the drill pipe, and open the bit shank lubricating device at the same time. In principle, it is better to see the bit shank lubricating oil at the bottom of the drill pipe. Second, the outside of the drill pipe, including the threaded portion and the main body of the drill pipe, must be wiped clean. At the same time, a rubber cover (as shown in the figure below) should be added to the male and female joints to prevent pollutants from entering. Storage and reactivation of impactors For short-term storage, follow these steps: First, blowing to remove the water in the impactor; Condly, filling 1 liter of bit oil from the upper joint part; Third, turn on the air and blow for about 10 seconds, so as to fully lubricate the internal parts of the impactor; Fourthly, like the drill pipe, the upper joint and the lower joint are respectively covered with a rubber cover; Fifth, place the impactor horizontally in a dry environment. Long-term preservation, slightly different First, blowing to remove the water in the impactor; Second, loosen the upper joint and the lower joint, and disassemble the impactor; Third, check and wipe all the internal parts, preferably in a clean room; Fourth, properly lubricate all parts with proper lubricating oil; Fifthly, assemble the impactor and cover the upper and lower joints with a rubber cover; Sixth, place the impactor horizontally in a dry environment. Reactivating the impactor requires the following three step First, disassemble the impactor and inspect all the internal parts. If it is found that the surface of some parts is oxidized, it is necessary to polish the oxidized parts with sandpaper. If the impactor is put into use without testing, it is likely to cause premature failure of the impactor. Second, clean the parts, wipe them clean and lubricate them. Thirdly, the cleaned and lubricated parts are assembled into an impactor, which can be put into use. Read the above article, may be a lot of people think, we usually put casually, do not still use?! Many users will record the wear and tear of drilling tools, such as a hammer used for several months and so on. In today’s market depression and fierce competition, the price of rock drilling has been declining. Xiaobian suggests that our majority of down-the-hole drilling rig users can try to work hard on maintenance, such as using and preserving drilling tools according to our suggested methods, carrying out reasonable maintenance and lubrication in strict accordance with the requirements, and trying to see if the life of drilling tools can be longer than before, so as to help you save more money. Machines are more reliable than people. If you are good to machines, machines will be good to you. Reprinted from the network,Borehole Drill Bits, the copyright belongs to the original author, if there is infringement, please contact to delete! You see this article with · Return to Sohu to see more Responsible Editor:. wt-dthtools.com

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