The Xs RU (retrievable/reusable) system is used with any size casing that needs to be retrieved from the ground.
The rotating part of the crown has a larger diameter than that of the casing and has relief grooves on its periphery to help in the retrieval process. This system has a butt welded connection. The Xs RU system is used with any standard size DTH hammer.
The driver bit is the device that transfers impact and rotation to the crown bit for drilling. The driver bit locks into two or four flats on the casing crown and they act together as a standard drill bit, both the driver bit and the crown have tungsten carbide buttons.
The crown bit is a two-piece unit permanently connected together. The upper part is butt-welded to the casing, and the lower part, which has Tungsten Carbide is free to rotate with the driver bit.
- Impact zone: Direct energy from the hammer is transferred to the crown bit through four (4) recesses (Xs T version) or two (2) recesses plus a projection all around the periphery of the driver (Xs S version).
- Evacuation: Two (2) big air holes are drilled in the face of the bit (drilling end). Those holes are directly connected to two (2) large flushing air ways, these flushing grooves transfer the drill debris from the drilling end of the driver up to the hammer zone. To help keeping a good flow of debris, two (2) other smaller air holes in the flushing air ways, help give the cuttings some velocity.