Here we will give the high level introduction on how to select the DTH drilling tools, due to they are the key components for borehole drilling.
Hammers and bits
- Generally the hammer should be selected to match the maximum operating conditions for the compressor
- The recommendation is that the hammer shall use about 85% of the compressor air delivery capacity
- The bit should be selected to give best possible drilling rate and service life in present rock conditions
- Bit face and head design
- Flushing holes
- Button shape and carbide grade
Drill pipes
- Drill pipes should be selected to meet high demands on:
- Wear resistance
- Long thread life
- Strong and reliable tool joints
- Easy coupling and uncoupling
- Low weight
Hammer Type
- There is a vast array of DTH hammers on the market
- Apart from standard there are three other hammer types available:
- Heavy duty
- Deep hole
- Reversable
- Heavy duty (Hardrock H-line)
- Robust and more wear resistant hammer casing for drilling in abrasive rock
- Deep hole (Hardrock W-line)
- For water-well drilling or oil and gas drilling Designed to maintain performance where high back pressure is encountered.
Also allows more air to pass through the hammer to boost flushing
- Reversable (Hardrock R-line)
- Reversable piston casing to better cope with steel wash in the forward section of the hammer
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