Air Rotary Casing Hammer Technique (ARCH)
Definition - What does Air Rotary Casing Hammer Technique (ARCH) mean?
Air rotary casing hammer technique (ARCH) is an air rotary technique used for drilling in rock formations. Air rotary drilling utilizes air as the circulating medium instead of a fluid such as bentonite slurry. The air cools the drill bit and also brings the cuttings to the surface to keep the bore hole clean. Trenchless construction methods require boring a hole into the earth's surface from an entry point to the desired exit point without breaking the ground surface over the entire pipeline length.
These methods are non-disruptive to surface traffic and also to environmentally sensitive areas such as lakes, rivers and wetlands.
Trenchlesspedia explains Air Rotary Casing Hammer Technique (ARCH)
ARCH, also sometimes called top drive, a rotating drill head and an impact hammer above-hole provide the necessary impact force and rotational down force required for boring. The impact force provided by the hammer aids in the drilling process.
The borehole is advanced by the rapid rotation of the drill bit mounted at the end of the drill pipe. The formation is cut into small pieces called cuttings by the drill bit. The cuttings are removed using compressed air at high pressure from the center of the drill rod. The cuttings come out from the annular space between the drill rod and the borehole.
The removal of cuttings is a very important part of the drilling process in order to keep the hole clean to allow the bit to move freely.