Permanent Model
The ring bit will be left in the hole after drilling finished.
This system drills in any direction and in any type of ground condition.
It is, in fact, the most flexible and efficient overburden system on the markettoday.
The Symmetric components are made up of:
---A pilot bits with large internal flushing holes and external flushinggrooves
---Symmetrical ring bit (reamer) with internal bayonet coupling
---Casing shoe for driving of casing.
The Pilot bits is attached to any common DTH hammer shank.
The Prodrill 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.
Application Range: suitable for drilling water wells, geothermal wells, short mircopiles, medium mini-type grouting hole of building, dam and harbor project.
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. Hammer’s percussive energy is transferred through the pilot and ring bits, crushing rock . Part of impact energy advances casing.
3. On completion of drilling and casing , the drill string with 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 retrieved4. Drilling continues to the desired depth in the bedrock using a conventional drilling.
SOD-610-Retrievable Symmetric Casing System by DTH Hammer: