Jet Grouting

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In Cologne, Germany a new subway was built near the city centre. Before construction with a tunnel boring machine could even begin, the surrounding buildings had to be stabilized by a injection of a cement suspension. This process is called jet grouting. Two shafts were installed. From here, work was carried out to stabilise the foundations of the adjacent residential buildings. Depending on the shaft, different numbers of transverse boreholes with a depth of up to 50m were drilled. The boreholes were then grouted with a cement suspension.

Contractor
Biergans Pumpen Vertrieb

Tsurumi support
Density assessment of the liquid that had to be pumped, as well as dewatering process development including slurry removal.

The problem

The liquid that needed to be removed/pumped from the construction site contained high levels of abrasive cement. The contractor was using pumps made of aluminium or heavy sewage pumps beforehand which caused a lot of maintenance in the process, as well as downtime. Additionally, air pressure inisde of the pipes developed, once the pump stopped working. This phenomenom would create an air bag inside of the pump. If the pumps started operating again, they were effectively not moving any liquid or substances as they were literally puming air.

The solution

The Tsurumi engineering team proposed NKZ3-100H (11kW) for heavy duty applications. It is especially designed for abrasive applications providing additional protection for the mechanical seal while preventing the development of air pockets inside the casing of the pump. Therefore, stop and go operation with Tsurumi in this heavy applicaiton is no problem! 2 years of continous operation with no maintenance and no failure!

Specifications NKZ

In the event of abrasive and corrosive utilization, stronger wear and tear will take place naturally in certain components. With regards to the above application wear and tear can take place mainly in impeller, agitator, suction plate, shaft sleeve, oil ring, mechanical seal, pump casing, strainer, motor casing and discharge coupling. Depending on the working conditions the lifetime of those parts might vary significantly and can be shorter than the legal warranty period.

In this regard, please pay attention to our general terms and conditions that we also send to you by mail on request.