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       Address: Unit 8001, Part A, Minnan Culture Town, 

       No.350, Changle Road, Huli, Xiamen China.361006


Symmetric Overburden Drilling System

Symmetric Overburden Drilling System

The symmetric drilling system is designed to drill and case a hole simultaneously through unstabled ground conditions. The driver bit incorporated with a satisficial ring or reusable ring makes a full face head design which significantly improves the penetration rate and hole straightness of drilling. The internal flushing grooves together with the built-in casing shoes gives a good seal to the button of the drilling hole, and thus minimising the disruption of the surronding of the drill hole.

Concentric/symmetric overburden system
In the projects of drilling,drillers often meet with problems due to the loose land formation.These may cause troubles such as difficulty in drilling down,collapse of holes,damage of drilling tools,etc.To solve the problems,the best way is to use (ODEX)Overburden Drilling System which can prevent holes and drilling tools from damage,and support the holes by casing tubes.

General Introduction 
1.drill in overburden unstable rock step to drill and follow casing 
3.flexible to open or close 
4.effecient below 300mm 
Design Principles:
Make the casing follow easy and the equipment and operation simple 
Outstanding Advantages 
Simple structure,simple operation,reliable quality,retrievable drilling tools,long service life.
Raw Material 
first class special alloy steel with high strength, heat resistance and wearable
The best tungsten carbides from China are commonly applied.
Tungsten carbide from European is also available.

Working Process:
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's upper shoulder engages the shoulder of the casing shoe.
2. On completion of drilling and casing, the drill string with pilot bit is retrived 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.
3. Hammer's percussive energy is transferred through the pilot and ring bits, crushing rock. Part of impact energy advances casing.
4. Drilling continues to the desired depth in the bedrock using a convertional drilling.

Product typeCasing ODCasing wall max.Ring bit IDRing bit ODPilot bit ODHammer

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