The cutting tool for core barrel can be either Bullet Teeth or Roller bit depending on the strength of the hard rock. It uses the same drilling principle of the core barrel. Before the stone core is lifted(took out), the method of the drill is the same. When the drilling is finished, the stone core will be taken out together by this tool.
The Structure of the Core barrel
1)With dual accident prevention function, the core barrel is equipped with a twist-off prevention device and an accident prevention cable. Once the rotary shaft breaks, the core barrel will not fall into the hole
2) Set limit height device, when drilling hard rock, it will not cause the core to wear and destroy the upper mechanism due to the long-time drilling (long stone core)
3)Compression spring device, This device ensures that the two bucket flaps are stretched to the maximum when the core barrel is drilled into the hole or during drilling, and it will not tremble due to the jitter of the drill rod, so that it can prevent the stone core from being squeezed between the bucket flap and the core barrel wall, and cause broken the bucket flaps
4)This Core barrel can be used not only in hard rock but also in pumice formations with gravel diameters greater than 250mm.
Core Barrel drill operating procedures
1)Before running the core barrel, the flexibility of the mechanism must be checked at the orifice.
2)Bucket flaps must enter the hole when fully stretched.
3)The initial drilling can not be pressurized, and then gradually pressurized after the backdrilling is stable. At this time, the core barrel should not appear to skip(move up and down).
4)If countersinking or stuck drilling occurs during drilling, stop pressurizing and do not use reverse drilling
5)During the drilling, it was found that the slewing resistance suddenly increased. At this time, it can be preliminarily judged that the core has been broken, and it can be reversed 2 to 3 times, and the core barrel can be lifted.
6)During the drilling process, a sudden pressure loss is found, that is, there is no resistance when turning. You need to stop drilling immediately and check to prevent the rotating shaft from breaking.
Post time: Nov-09-2022