reduced from the heat treatment and processing technology of the material of the
cylindrical teeth.
(2) Unmatched design of bottom lip and rock properties
As shown in Fig. 11.47, the spherical teeth on the most central arc top have less
contact with rock and soil, which means that these spherical teeth do not work
under the same working conditions as other teeth. This not only wastes energy but
also affects the drilling efficiency of DTH bit. On the one hand, this problem is due
to the too large radian of concave surface in bit design. On the other hand, it is also
related to the geotechnical properties of drilling. It can be seen that the arc of the
drill should be reduced appropriately in the design of the drill bit, and the appropriate type of drill bit can be selected according to the specific geotechnical
properties in the construction.
Bibliography
1. Yin Y, Shuai H, Hongjuan L (2013) Analysis of sealing characteristics of pneumatic check
valve used for down-the-hole hammer. Fluid Power Trans Control 5:1–4
2. Yin Y (2013) R&D and industrialization of key equipment for construction of underground
diaphragm wall and pile foundation of complex stratum. National science and technology
support plan, 2012 The report
3. Yin Y-B,Yu L, Zhang H. Hydraulic pneumatic pilehammer: 201020676102.2, 23 Dec 2010
4. Yin Y-B, Wu J, Yue Y. Hydraulic pile extractor device: 200810201704.X, 24 Oct 2008
5. Yin Y-B, Yaobao C. Fundamental research on aerodynamic asymmetry mechanism and
high-speed aerodynamic control of gas resistance and gas capacity. Project supported by
national natural science foundation of China, Annual report 2012,2013
Fig. 11.47 Central spherical
tooth unequal working
conditions
266
11 Pneumatic Down-the-Hole Hammer
cylindrical teeth.
(2) Unmatched design of bottom lip and rock properties
As shown in Fig. 11.47, the spherical teeth on the most central arc top have less
contact with rock and soil, which means that these spherical teeth do not work
under the same working conditions as other teeth. This not only wastes energy but
also affects the drilling efficiency of DTH bit. On the one hand, this problem is due
to the too large radian of concave surface in bit design. On the other hand, it is also
related to the geotechnical properties of drilling. It can be seen that the arc of the
drill should be reduced appropriately in the design of the drill bit, and the appropriate type of drill bit can be selected according to the specific geotechnical
properties in the construction.
Bibliography
1. Yin Y, Shuai H, Hongjuan L (2013) Analysis of sealing characteristics of pneumatic check
valve used for down-the-hole hammer. Fluid Power Trans Control 5:1–4
2. Yin Y (2013) R&D and industrialization of key equipment for construction of underground
diaphragm wall and pile foundation of complex stratum. National science and technology
support plan, 2012 The report
3. Yin Y-B,Yu L, Zhang H. Hydraulic pneumatic pilehammer: 201020676102.2, 23 Dec 2010
4. Yin Y-B, Wu J, Yue Y. Hydraulic pile extractor device: 200810201704.X, 24 Oct 2008
5. Yin Y-B, Yaobao C. Fundamental research on aerodynamic asymmetry mechanism and
high-speed aerodynamic control of gas resistance and gas capacity. Project supported by
national natural science foundation of China, Annual report 2012,2013
Fig. 11.47 Central spherical
tooth unequal working
conditions
266
11 Pneumatic Down-the-Hole Hammer