Reverse circulation drilling is also called central sample collection or double-wall drilling. This type of drilling usually uses a double-wall drill pipe. Drilling force is high wind pressure gas, which enters into the hammer through the gap between the outer pipe and the inner pipe. The hammer hit the drill bit to break rock, and the broken rock is collected into the pores on the drill bit surface, and then the rock samples are collected through the sample collection pipe and the drill pipe.
1. No pollution, the reverse-circulation DTH hammer can quickly pick up samples on the drill bit surface at the moment of rock fragmentation. The sample does not need to pass through the hammer length, thus avoiding sample contamination and loss.
2. High productivity. In broken and fractured rock, the penetration speed is superior to the ordinary hammer.
3. Dry samples can be collected even in water condition, because drilling cuttings are collected as soon as they produced on the drill bit surface.
4. High sample recovery. Samples are collected from the drill bit surface, so samples loss can be avoided in broken and fractured rock formations. Since the bit diameter is almost equal to the external diameter of the wear sleeve, the sample collection recovery rate can reach 98%.
- 1Simple internal structure, good rigidity of parts, ensuring the long service life and convenient maintenance.
- 2Collection tube is an integral type, which can be replaced without removing the hammer. After carburizing treatment, the collection tube is good in wear resistance.
- 3With the patented design of the drill bit, it only needs to replace the drill bit. The same hammer can be used for holes of different sizes, and the samples can be guaranteed to be free from contamination.
- 4The sampling work can be done well, even under various difficult conditions such as loose soil, hard rock and large amount of water.
|Length (bit excluded)||Weight (bit excluded)||External diameter||Hole Range||Working pressure||Impact Frequency||Recommended rotation speed||Air Consumption|