High-pressure drilling compressor
A 14 to 21 bar machine built to supply down-the-hole drilling tools and hammers, where pressure does the work and delivery clears the cuttings. A different machine from a 7 bar site compressor, not a setting on one.
Features
- Down-the-hole hammers convert air pressure directly into impact energy, so penetration rate tracks supply pressure closely.
- Delivery has to clear cuttings up the annulus as well as drive the hammer, and an undersized machine leaves the hole full.
- Two-stage compression is normal above about 14 bar, with interstage cooling, which is why these machines are heavier for the same delivery.
- Air line lubricators feed rock-drill oil into the supply, and consumption is a real consumable cost per drilled metre.
- Hoses, couplings and whipchecks have to be rated for the full pressure class, and 7 bar site fittings must not be used.
Specifications
| Figure | Typical range | Unit | Why it matters |
|---|---|---|---|
| Free air delivery | 7 000 - 21 000 | l/min | Determines hole diameter and depth that can be cleared. |
| Working pressure | 14 / 17 / 21 | bar | Directly sets hammer penetration rate. |
| Compression stages | 2 | Explains weight and interstage cooling requirement. | |
| Drive power | 100 - 250 | kW | Indicates fuel burn per drilled metre. |
| Discharge temperature | < 110 | °C | High values point to cooler or oil problems. |