146-DHD340 Symmetric drill bits with casing tube

Concentric Casing System

Working Principle of Drill:

1. Ring bit and casing shoe assembly is welded to casing prior to drilling. Lock the assembly into pilot bit with hammer. The pilot bit' shoulder engages the shoulder of the casing shoe.

2. Hammer's percussive energy is transferred through the pilot and ring bit, crusing rock. Part of impact energy advances casing.

3. On completion of drilling and casing, the drill string wit pilot bit is retrieved by a slight reverse rotation to unlock the bayonet coupling. The ring bit stays in the hole, and can be recovered only if the casing is retrieved.

4. If further drilling is required on the bedrock, the pilot bit is simply replaced by an appropriate size of standard DTH bit.

Advantages of Concentric Drilling:

1. Drilling straight and fast.

2.The torque for Concentric drilling is much less than for eccentric drilling

3. Easily unlocking-relocking.

4. Drilling in any angle.

5. Effective cuttings discharge.

6. Easy-to-operate and system security.

7. Economical and cost-effective.

---------------------------------------------------FAQ-------------------------------------------------------

Q2: Do you have the inspection procedures?
A:100% strict inspection and testing for every order before packing.

Q.Why choose us as your long-term business supplier?

A. High-quality products, reasonable price, professional team work.

Q. Do you have different type for different kind of stone?

A.Yes,according hardness of stone and stone's feature, we have different type respectively.

Q: How long is your delivery time?

A: Generally speaking, 5-10 days if have stock.Regular order delivery in 20~30 days if without stock.Otherwise it depends on your order Quantity.