The operating principle of HDD DTH drilling tools is similar to that of conventional down-the-hole systems. A pneumatic or hydraulic hammer is connected to the front end of the drill string, while the rear end is driven by a rotation unit. During drilling, the hammer advances to the bottom of the borehole, where compressed air or hydraulic oil flows through the drill rods into the hammer. The internal air or oil distributor activates the piston, delivering high-frequency impacts to the bit and fracturing the rock. At the same time, the rotation unit turns the drill bit, combining percussive action with cutting forces to achieve efficient rock breaking. The resulting cuttings are then flushed out of the hole by compressed air or circulating drilling fluid.
HDD Hammers (Horizontal Directional Drilling)
The HDD hammers operate at an impact frequency of 22-30 Hz and fracture rock primarily through percussive energy, significantly reducing rotational load on steering electronics and the drill rig. The HDD pilot hammers and reaming hammers deliver faster penetration even in extremely hard formations. All SPM’s HDD hammers are compatible with standard directional drilling rigs using DCI, Subsite, and U-Mag locator systems.
| Model | |
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| Drilling diameter, mm | 90-105 | 115-130 | 140-152 | 165-194 | 203-254 |
| Top sub thread | API 2 3/8 REG pin | API 2 3/8 REG pin | API 2 3/8 Reg pin | API 3 1/2 REG pin | API 4 1/2 REG pin |
| Hammer OD, mm | 80 | 98 | 124 | 146 | 185 |
| Effective hammer length, mm | 812 | 986 | 1094 | 1240 | 1346 |
| Hammer weight, kg | 25 | 39 | 70 | 108 | 193 |
| Air consumption, m³/min | 4.5@10bar 8.5@17bar | 5@10bar 9.5@17bar | 7@10bar 13.5@17bar | 9@10bar 17@17bar | 13@10bar 24@17bar |
| Reaming diameter, mm | 254-457 |
| Hammer OD, mm | 185 |
| Top sub thread | API 3 1/2 REG pin |
| Effective hammer length, mm | 1025 |
| Pilot bit diameter, mm | ≥140 |
| Air consumption, m³/min | 35@24bar |
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254 mm
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305 mm
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356 mm
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406 mm
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457 mm