| Energy is an important fundamental materials for human survival and development,is also an important factor affecting sustainability and rapidity of economic development,is the focus of attention in today's society.With the rapid development of the world economy,energy demand is increasing day by day,the conventional oil and gas reserves are becoming less and less.Oil shale,as an unconventional energy source,has huge reserves more than half of the world's recoverable oil reserves.In China,oil shale resources are second only to those in the United States and have broad prospects for development and utilization.At present,the main methods of oil shale mining are open.pit mining and underground tunnel mining,which construction cycle is long and the mining cost is high,and cause serious pollution on the ecological environment of mining area.Hydraulic borehole mining technology utilizes boreholes drilling through seams and the matching drilling tools to realize ore mining without underground manual operation to increase the security.Moreover,the construction cycle of the mining area become shorter,and the impact on the ecological environment of the mining area become smaller,especially on the thin seam and low.grade ore deposits,the advantages become obvious.Hydraulic borehole mining technology uses high pressure water jet produced by drilling tools to crush the rock of hole wall.The drilling radius is the key factor affecting the cost of hydraulic borehole mining.The position of high.pressure nozzle of the traditional hydraulic drilling tools is relatively fixed,which is limited by rock breaking capacity of high.pressure water jet,therfore the mining radius is smaller,causing many preparation works and high cost in the early stage of hydraulic mining.Based on above,it is necessary to make a deep research on the hydraulic drilling tools.By analyzing the technical parameters of high pressure water jet,the requirement of ore pulp lifting,the design requirement of drilling tools and working environment,this paper designs and develops a retractable hydraulic mining drilling tool to carry out the experimental verification of the processed drilling tools,which provides an important support for the popularization and application of drilling hydraulic mining technology.The main research contents and conclusions are as follows:1.By analyzing the working principle and characteristics of crank.slider mechanism and pawl.rack mechanism,the design proposal of telescopic hydraulic drilling tool with pawl.rack as telescopic control mechanism is put forward,whose drilling tool model is established by using Auto CAD and Solid Works.2.By analyzing the structural characteristics of drilling tools for hydraulic drilling,the structural dimensions of each component of the drilling tools are confirmed by theoretical calculation and simulation analysis,detailed structural design and strength check are carried out on the important component of the telescopic control units,then make the simulation analysis of telescopic control unit.Based on the above research findings,the drawing of the parts processing drawings and the overall assembly drawings are come out.3.According to the design requirement,the experimental method statement of drilling tool is compiled,and the field experiment is carried out on the processed telescopic hydraulic drilling tool.The main performances of the drilling tool such as telescoping,positioning,unlocking and sealing of high pressure water passage are tested.The results show that the radial extension distance of the nozzle of the telescopic hydraulic drilling tool can reach 3 m,and the mechanism work safe and reliable with effective completion of the expansion,positioning and in.place unlocking work,high.pressure flow channel at pressure of 10 Mpa does not leak. |
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