Fiber optic cable laying in gravelly underground in Austria - TERRA-JET TJ 3008 ES
Further development of the powerhouse TERRA-JET TJ 3008 ES The TERRA-JET TJ 3008 ES has been further developed in close cooperation with the customer requirements of GL Bau GmbH. The driving saddle was completely redesigned in order to ensure an even more reliable operation also under maximum load. The new power pack is driven from a 55 kW Hatz engine. The additional 11 kW are used for increased revolution speed at the drill rod. Particularly for the reaming and pipe pulling process, this brings a significant gain in productivity. Moreover, two gears for drilling are now available and the operator can choose between maximum revolution speed of 135 rpm (and reduced torque of 2‘000 Nm) and maximum torque of 3‘000 Nm (and reduced revolution speed of 90 rpm). That can be done through simple switching a hand lever. With 8 metric tons thrust- and pullback-force, as well as 3‘000 Nm torque, the TJ 3008 ES has the necessary power reserve for the normally smaller pipe dimensions in fiber optic projects to realize drilling distances of even 100 m in demanding gravelly underground. The TJ 3008 ES is designed with the approach of having driving components separate to the actual compact drilling rig. Although this requires a fix set up of the power pack and mixing and pumping unit including bentonite tank on the truck, that allows installation and working in job sites with confined space conditions. The truck only needs to be placed near the actual installation site, from which the pit launched rig is supplied with power and bentonite through hoses. This corresponds to exactly the requirements which GL Bau GmbH is facing in the area of Salzburg.
In Frankenburg / Upper Austria a new drinking water pipe with outer diameter 90 mm had to be installed. The course of the pipe was meant to follow the road, so that the later installed valves for house connections were to be laid at the road rim but still within the asphalt surface. The starting pit for the TJ 3008 ES was chosen in a way that it could be used to drill in both directions, road up- and downwards. With 1 m drill rods and a machine length of 2 m the compact pit launched HDD rig is ideal for urban areas with confined space conditions. The drill starts directly where the pipe needs to be installed, hence no additional drill meter and pipe length are needed. The TJ 3008 ES allows pulling the drilling tools and pipe into the machine at the end of the bore. As a result drilling tools can be dismounted within the drilling rig and the shortest possible starting pit size can be realized. The break-apart system is loosely supported for that purpose.
Pic 1: Creating the first pilot hole controlled over 42 m. Pic 2: The DJ 18-PIT can be installed in pits with a minimum length of 2.10 m. Pic 3: The DJ 18-PIT is lowered into a pit here. Pic 4: Locate with the DigiTrak F5. Pic 5: Accurate arrival of the pilot hole into the narrow target pit. Pic 6: The pressure water pipe 90 mm was quickly pulled in with the DJ 18-PIT.
