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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
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