The directional drilling technique of the Grundopit drill rigs comes into operation in topographically difficult terrains. For example, this is a possibility when installing a new private sewer connection leading to the transfer manhole. The Grundopit Type S can be started directly from an inspection chamber with a previously prepared core bore hole. For most application cases, this completely saves the bother preparing pits.

With Grundopit ‘Manhole’ fibre glass cables can be installed in protection pipes ND 50 (out of a pit and into a cellar) or in protection pipes ND 100 (from manhole to manhole) for the first time without trenches.

And this is the way it works: The bore rig is set up on a working platform, which has been positioned and anchored in the manhole beforehand. The working platform, driven out by hydraulics, adapts itself to the inner diameter of the manhole utilising the support given by the manhole walls. Holding ropes secure the working platform additionally.

First of all a core hole borer, connected by an adapter, bores a 150 mm hole through the manhole wall. After this the tool is exchanged, the standard bore head or the specially designed hammer bore head for heavy soils is screwed to the 50 cm long drill rods. Then the rods are thrusted forward swiftly, the bore course is constantly monitored and corrected, if required. Drilling fluid is usually necessary, it can be prepared in thedrilling fluid mixing unit belonging to the machine.After the drilling fluid has been used, it is collected in a facility and disposed. The bore head can "drive" via pre-drilled core hole bore, through the house wall intothe cellar. After the pilot bore the bore hole is expandedand the protection pipe is pulled in.