HÜDIG - Renewal of a mixed water channel
The company Hagemann and Knust has been awarded a contract in Burgdorf, near the capital city Hannover, to renovate mixed water sewers at the corner of Immenser Street and Dammgarten Street. The mission is to have a shaft located on a mixed water channel with a depth of approx. 4 m, into which currently two further mixed water channels flows, demolished and replaced by a new reinforced concrete shaft (-work in progress). The 4.5 m deep pit, which was excavated and built with sheet pile walls, has dimensions of approx. 10 x 8 m.
Specification: The groundwater in the excavation pit must be lowered by 1.5 m. For this purpose, a total of 24 jetting filters were jetting into the subsoil (consisting of coarse sand / sand).
The company Hagemann and Knust use two diesel vacuum aggregates of type HC 522 from the HÜDIG rental park for this purpose. With the help of HÜDIG diesel vacuum aggregates, 50 m³ of groundwater are pumped hourly and then fed through two discharge pipes, each about 50 m long, to reduce excess sand, first through a sand trap and then finally into the Gümmelchannel. A third HC 522 diesel vacuum aggregate from the HÜDIG rental park is located on the construction site in Immenser Street for the preparations for the second construction phase, in which further pipelines are to be renewed. In total, the HC 522 has been in continuous operation for four weeks without any complaints. Since the dry-running rotary vacuum generator has a maintenance interval of up to 3000 operating hours and only then a visual inspection of the wear parts is necessary and, according to the enginge manufacturer, an oil change only has to be carried out after 1000 operating hours, the work on the construction site, when using a HC 522, is in the foreground. Thanks to the optional equipment HC 522/07 longrun, with a tank volume of 511 liters, a maintenance-free continuous operation over a period of 12 days is possible.
The diesel-powered waste water pump und vacuum generator ensure for a continuous delivery of the water-air mixture. Using the air separator tank upstream of the water pump, any air present is separated from the water so that the water pump only pumps water. This combined system achieves a fast reliable suction as well as a powerful vacuum.