Double rotary drilling

Two rotary drives are separately mounted on the sledge and independently drive the inner continuous flight auger and the casing.

During the drilling process the auger flights convey the drill cuttings to the surface inside the casing. Through an opening at the upper end of the auger the drill cuttings are ejected.

The compact design of the double rotary head allows operation very close to existing building structures, i.e. in front of building walls.

A protection cover encloses the casing so creating an annular space inside. Thus, the ejected drill cuttings fall to the ground in a controlled manner.

After their extraction, casing and auger are swung to the side and emptied by rotating the auger in the reverse direction.

After the final depth has been reached concrete is pumped through the auger’s hollow stem. During the extraction process the concrete exits at the lower end of casing and auger.

After concreting a reinforcement cage can be inserted in the column of fresh concrete. For this purpose the auxiliary winch of the carrier machine is used.