Eccentric Overburden Drilling System| Type | Hole Diameter(mm) | NO. Air Hole | Buttons | Casing Size
( Wall Thickness * Outerdiameter) | Size
(Diameter*L) | Weight
(KG) | Hole deep(m)
(f=4~6) | Match DTH Hammer | | DR108 | Φ108 | 3 | 10 | Φ108*(4.5~7) | Φ93X319 | 9.4 | 200~600 | DR90 | | DR127 | Φ127 | 3 | 11 | Φ127*(4.5~7.5) | Φ110X355 | 14 | 200~800 | DR110 | | DR146 | Φ146 | 3 | 14 | Φ146*(4.5~7.5) | Φ129X355 | 18 | 200~800 | DR110 |
Advantages:
It is Mainly made of ladder shaft shaped centralizer and using connecting pin installed in centralizer with eccentric bit, due to the connecting pin in full in the process of drilling torque, connecting pin put on eccentric drill bit and centralizer cylinder parts, it is very simple to use, driving ability outstanding ,slag discharge effect is excellent.
Working Principles: When drilling, the reamer swings out and drills a hole larger than the external diameter of the casing tube. When the required depth has been reached, the drill is reversed and the reamer swings in to its minimum diameter, allowing the bit to be lifted up through the casing, which is left in the hole. Drilling can continue with an ordinary DTH drill bit.
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