1. When drilling starts, the reamer swings out and reams the pilot-hole wide enough for the casing tube to slide down behind the drill bit assembly.
2. When the required depth is reached, rotation is reversed carefully, whereupon the reamer swings in , allowing the drill bit assembly to be pulled up through the casing.
3. Casing tubes that are to be left in the drill hole should be sealed at the bottom of the hole by means of cement grout or some other sealing agent.
4. Drilling continues to the desired depth in the bedrock using a conventional drill string.
This product is made of alloy of high quality and apply for advanced high-frequency welding technology and maturity of heat treatment process, greatly improving the intensity, wear resistance and impact toughness of cutter head, increasingly prolonging the working life, enhancing the drilling efficiency.
It is recommended to drill in rock formation where contains some ovals and fractures.
Make the casing follow easy and the equipment and operation simple
The stable and reliable working performance and the less vibration of drill rig and flexible to open and close.