Dual Rotary Heads DDK

The characteristics of the patented DELMAG DDK-System (Double Rotary Head) compared to conventional double rotary head systems are that the upper rotary head (auger drive) can be moved independently from the lower rotary head (casing drive).

The DDK-System has received the award for the best innovation at the bauma show in 1998.

Therefore it is possible to drill down in one pass, retract the auger, install the re-bar cage and pour the concrete into a hole that is still protected by a casing. After pouring the concrete, the casing can be extracted using the lower rotary head, while the auger is still connected to the upper rotary head.

It is also possible to pump concrete through the center of the auger while pulling the auger. The casing can remain in the ground until the re-bar cage is installed and can be extracted afterwards by using the lower rotary head. Of course auger and casing could also be extracted simultaneously. For this method, any relative position of auger tip to casing shoe can be chosen, which allows an increased concrete head pressure, compared to a conventional Double Rotary Head system.
Using the DELMAG DDK-System higher daily production can be obtained compared to the conventional Kelly drilling method, if soil conditions, jobsite conditions and logistics allow the use of the DDK-System.