Development of a specially designed drill bit for down-the-hole air hammer to reduce dust production in the drilling process
Development of a specially designed drill bit for down-the-hole air hammer to reduce dust production in the drilling process
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DOI：
10.1016/j.jclepro.2015.08.014
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发表时间：
2016-01
影响因子：
11.1
通讯作者：
L. Yongjiang;Jianming Peng;Lijia Li;He Jiangfu;Xin Gan;K. Yin;Z. Zhao
中科院分区：
文献类型：
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作者：
L. Yongjiang;Jianming Peng;Lijia Li;He Jiangfu;Xin Gan;K. Yin;Z. Zhao
针对反循环潜孔空气锤设计了一种特殊结构的钻头，以减少作业过程中钻井现场附近的局部粉尘产生。进行了计算流体力学和实验研究。结果表明，吸嘴的喷雾速度对除尘钻头的性能有重要影响。为GQ-89型反循环潜孔空气锤研制了3台优化钻头，并在小秦岭金矿区进行了垂直向下钻孔现场试验。这些钻头有两个直径为8毫米的中压恢复槽，两个对称放置的直径为3毫米的冲洗喷嘴，以及六个均匀分布的吸嘴，每层直径为6毫米。现场试验表明，采用反循环潜孔空气锤配合特殊设计的钻头，在钻井过程中具有良好的防尘效果。特殊设计的钻头不需要额外的密封装置，可提供高达99%的防尘效率，高于湿法钻进和干法钻进，关闭钻探区域。目前设计的钻头采用反循环潜孔空气锤能有效地保护钻井工人和设备免受钻井粉尘的威胁。专门设计的钻头的使用也大大简化了井下空气锤钻进法的防尘装置。
A specially structured drill bit is designed for a reverse circulation down-the-hole air hammer to reduce dust production in the local vicinity of the drilling site during operation. Computational fluid dynamics and experimental studies were conducted. Results show that the spray velocity of suction nozzles has an important effect on the performance of the drill bit for dust control. Three optimized drill bits were built for a GQ-89 reverse circulation down-the-hole air hammer and field-tested by drilling vertically downward boreholes in Xiao Qinling gold ore district. These drill bits have two mid-pressure restoring grooves with a diameter of 8 mm, two symmetrically placed flushing nozzles with diameter of 3 mm, and six uniformly distributed suction nozzles with diameter of 6 mm for each layer. Field tests show that employing the reverse circulation down-the-hole air hammer with specially designed drill bit has good dust control performance in the drilling processes. The specially designed drill bit can provide dust control efficiency of up to 99% with no need for additional sealing device, which is higher than both wet drilling and dry drilling by closing the drilling area. And employing reverse circulation down-the-hole air hammer with the current designed drill bit can efficiently protect drilling workers and equipment from threats of drilling dust. The usage of the specially designed drill bit has also significantly simplified the dust control apparatus for down-the-hole air hammer drilling method.