Demonstration of the Keyhole method in Lennestadt and Hamburg / Germany

09.01.20 - With the minimally invasive Keyhole-Technology, house connections for gas and water can be installed in an especially gentle and economical way. With this innovative method, a steerable bore starts from a circular launch pit of maximally Ø 65 cm directly above the main service line. In order to produce these “Keyholes” a concrete or asphalt core is bored out of the road surface and after completion of the work, re-fitted exactly back into place. This way surfaces are only minimally utilised, therefore no need for any asphalting or subsequent repair work. For this reason, the “Keyhole-Technology” is especially suitable for serial applications. Representatives of renowned service companies were able to convince themselves, within the framework of several exclusive demonstrations during the past few months.

Keyhole Day in Lennestadt

In July of this year, TRACTO-TECHNIK invited representatives of network operators, who have been entrusted with the new planning, or the sanitation of house connections, to a special “Keyhole-Day” in Lennestadt with practical demonstrations. Werner Weßing, Head of Application Engineering, Research and Development at E.ON Ruhrgas, presented the event, together with Philipp Schumacher, the responsible product manager at TRACTO-TECHNIK.
The day started with a lecture under the title, „Keyhole – The starting pit of the future is small and round“. With a comparison of the Keyhole-Technology, comprising the trenchless and open-trench installation methods the procedure, the functionality and advantages of the method were outlined. Afterwards, the theory was further illustrated by a practical demonstration at TRACTO-TECHNIK’s test-site, adjacent to the technology centre in Lennestadt-Langenei, where all the single components were presented. They included a coring unit, which cuts open the asphalt core, a suction excavator, which vacuums the keyhole right up to the main line, the steerable bore rig GRUNDOPIT KS50 and special telescopic tools, which can carry out all necessary connection work above the surface. These tools, also called Long-Handling-Tooling (LHT), were developed for numerous tasks. The visitors from Avacon, Gas Networks Hamburg, SH Networks, the Bayernwerk and Stadtwerke Hamburg were shown an example on how to assemble a weld-on saddle and how simple a bubble can be set through the keyhole. In the subsequent discussion, all the participants were in agreement, that the complex method is a caring and cost-effective solution, especially for serial applications. This is especially the case, if the Keyhole-Technology is also applied, not only for the installation of house connections, but also for inspection and maintenance work, repair work and also link-ups and re-clamping of house connections.

Application of the Keyhole technology for Hamburg Water Services

After the Berlin Water Companies‚ the ‘Hamburg Water Services‘, is the second largest communal water supply and disposal company in Germany. After the Hanseatic city’s municipal gas supplier had successfully tested the Keyhole-Technology last year (see report in Tractuell 55), the management of the drinking water supply company now wanted to apply the method for the renewal of several water-house connection pipelines in the Northern and Central regions. TRACTO-TECHNIK provided the equipment and the operating crew and the suction excavation work was carried out by the company Max Huss.
On the first day, the task was to remove an old house connection in Hamburg-Reinsbeck, as the adjacent house was going to be demolished. In doing so, the old connection had to be clipped off by boring a keyhole with the telescopic tools at the appropriate spot, the old fitting made of 110 mm ductile cast iron removed and the connection separated from the main line by inserting a blind cap. This was all completed in, believe it or not, 3 hours. Then two pushing rods were exchanged through the keyhole, which also only took 2 hours.
On the second day the complete renewal of three house connections lines, including fittings, were scheduled in Großmannsdorf. The distance of the old lead or steel pipes with 30 mm Ø from the main line to the property border was 2 m, 5 m and 11 m, respectively. They were replaced completely underground, within a new bore path with Ø 65 cm PE pipes and equipped with new fittings from the surface with special tools. Only for the handover “from old to new”, small pits on the properties were necessary. In total the water only had to be switched off for 20 minutes, which meant that not only a complete house water connection was newly installed, but also the pipeline capacity was increased in one go.
The managers in charge were extremely satisfied with the Keyhole-Technology and its safe application. Even the CEO from Hamburg Waterworks was on site, to convince himself about the results. Now the water supplier is checking, whether the Keyhole-Method can be applied for an uncomplicated and gentle exchange of hydrants. A training session for the crew for the handling of the LHT-special tools is already being planned.

Special offer for suppliers and network operators

To suppliers or network operators who are interested in a demonstration of the keyhole technology in their area, we offer a special introductory package at attractive conditions. The 'House Connection Technology' package includes supply, transport and set-up of the equipment, execution of the bores and installation of the lines as well as the connection works by qualified personnel. Documentation and analysis of the measure as well as a presentation of the method are also included. If you are interested in a demonstration, please contact our sales department or Philipp Schumacher (product manager) philipp.schumacher@tracto-technik.de



You can reach us by phone




Do you have any product or
services related questions?

Please contact us:

+61 7 3420 5455