| Popis: |
To achieve cutting transport with air reverse circulation in dry and shallow large-diameter holes of rock-socketed pile, and to solve the technical problem with airlift and pump reverse circulation, a large-diameter reverse circulation bit innovatively designed based on ejecting. Meanwhile, the orthogonal design method applied to explore the application feasibility of ejector theory in use of in air reverse circulation drilling. Through theory analysis, three key geometry parameters of air reverse circulation bit have proved to have direct affect on the function of cutting transport, including the diameter of nozzles (Dn), the number of nozzles (N), the angle of inclination (θs). The results have shown that reverse circulation effect of large-diameter bit designed based on ejecting is valid and stable. Further while the air volume of GQF-16 hammer bit goes to 90m3/min, a configuration of parameters with Dn=20mm, N=3, θs=35°are the most ideal parameter combinations. |
