Reverse Circulation Hammer (RC Hammer)
Definition - What does Reverse Circulation Hammer (RC Hammer) mean?
The reverse circulation (RC) hammer is a simple non-electrical air motor that is driven by high-pressure air.
An RC hammer exhausts the air down the outside splines of the percussion bit and then up its holes through the internal diameter of the hammer and the drill string to the surface.
During the drilling operation, the percussion cycle is activated by the RC hammer into which air from the compressor is blown through the swivel inlet located between the outer and inner tubes.
When the percussion cycle ends, the cuttings are picked up by the same airflow and passed from the bit face through the inner tube to the surface where the RC cyclone collects it.
Trenchlesspedia explains Reverse Circulation Hammer (RC Hammer)
The reverse circulation hammer system works by feeding high-pressure air through an intake system that controls a piston which delivers the energy to the percussion bit.
The percussion bit and the air passages control the air exhaust system. The air that exhausts from the hammer also carries drill cuttings back to the surface. The power of the hammer will be restricted if the flow of exhaust air is limited by any obstruction.
When the RC hammer gets stuck downhole due to debris from cuttings, there can be costly delays and a reduction in the production rate. Blowback system is installed in rigs to clear sample blockages during the drilling operation and increases oil productivity.