Analysis on structural design and experimental effect of two kinds of hollow-through DTH hammer reverse circulation bits

Analysis on structural design and experimental effect of two kinds of hollow-through DTH hammer reverse circulation bits

Yanshun Zhao  Peng Li  Qilei Yin  Tong Wang 

College of Construction Engineering, Jilin University, Changchun 130026, China

Xian research institute of China Coal Research Institute, Xian 710043, China

Changchun Institute of Technology, Changchun 130026, China

Corresponding Author Email:
30 June 2017
| Citation



The good reverse circulation effect is the key to the reverse circulation drilling of the hollow-through DTH (Down-the-hole) hammer. For this reason, our research group has developed and designed two kinds of new type of reverse circulation bits. Hydrodynamic software is used to comparatively analyze the flow fields of the two kinds of bits. The simulation experiment shows that the slit-type inner nozzle structure has better pumping effect and the speed cloud chart shows that the wall effect of the slit structure is the best, and its flow field is evenly distributed, which greatly reduces the interference effect of the fluid. In Yuanjia Village Iron Mine in Lanxian County of Taiyuan Iron and Steel Group, a field test is conducted on the slit-type inner nozzle reverse circulation bit, indicating an accumulative footage of 43.2m, and drilling efficiency of 12.8m/h or more per hour. The field test shows that the newly developed slit-type reverse circulation bit has good reverse circulation effect, and realizes the highly efficient and fast drilling of hollow-through DTH hammer reverse circulation bit, which has greatly improved utilization performance


 reverse circulation bit, hollow-through dth hammer reverse circulation bit, slit-type inner nozzle structure, the double-row inner nozzle structure

1. Introduction
2. Principles of reverse circulation bit structure
3. Design and comparative analysis of two reverse circulation bits
4. Field test effect
5. Conclusions

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