Jun 20, 2019
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New primary crusher in proven steel construction

The quarry Jakob Bauer Söhne GmbH & Co. KG has been processing rock near Esslingen, Germany since the 1920s. The demand for qualitative aggregates in Stuttgart area is very high as the large construction sites are practically on Jakob Bauer Söhne's doorstep.

Their gravel plant in Erkenbrechtsweiler produces chippings and gravel for road and road construction. Another focus is the production of concrete chips, i.e. for the manufacture of segments for tunnel construction. "Stuttgart 21, the Stuttgart-Ulm rapid-transit railway or the Bossler tunnel are just a few projects in which our concrete aggregates are used," says plant manager Siegfried Militsch. The most common grain sizes are on average 2/8, 8/16 and 16/22 mm.

Michael Silvester of Metso (left) next to plant manager Siegfried Militsch (right) of Jakob Bauer Söhne in the Erkenbrechtsweiler quarry

Rebuilding revealed the need for a new crusher

Just in time for the turn of the year, the management of the quarrying plant decided to rebuild the pre-crushing station - including the replacement of a stationary integrated excavator and the installation of a new monitoring cage for the pre-crushing operation. The original idea was to replace the stationary excavator with a mobile mini excavator equipped with hydraulic hammer to support the crushing operation with an improved and more flexible technology.

It came out during the renovation that the old jaw crusher had cracks around the inlet and below it for the coarse limestone. However, this was not a surprise as during the last decades, millions of tons of rock had already been fed to the crusher. This raised the issue to a totally new level. A repair would only have been possible if the crusher was removed from the steel construction and brought to the factory for the necessary welding work. This made Jakob Bauer Söhne to think about an alternative solution. 

Larger inlet, higher performance with Nordberg® C125™ jaw crusher

In this context, the desire was expressed to optimally design the inlet width of the new crusher in relation to the outlet width of the roller grate for the feed material. A crusher with 120-125 cm inlet width was looked for. Prior to this, however, it was necessary to examine whether the integration of a new crusher in the existing steel construction would be possible under the given circumstances. The best solution for their needs was a modularly designed Nordberg® C125™ jaw crusher. And luckily, it could easily be integrated into the existing steel structure after having simulated the integration with a template.

"From the beginning, we were looking for a particularly compact breaker unit that could easily be installed in our current steel construction and that could also start operating as quickly as possible," says Siegfried Militsch.

"From the beginning, we were looking for a particularly compact breaker unit that could easily be installed in our current steel construction and that could also start operating as quickly as possible," says Siegfried Militsch.

New hybrid excavator with hydraulic breaker and wider feed opening of the new jaw crusher. This point was previously the production’s bottleneck.

Fast and successful installation 

Just a week after the decision, the C125 jaw crusher was lifted into the steel structure with a large crane and moved into the right place. The commissioning went smoothly. The new jaw crusher is running continuously with a small gap opening due to its much higher possible performance. As a result, also the downstream impact crusher was relieved. This has led to a significantly lower parts wear.

For more information:

Michael Silvester, Sales Crushing and Screening Technology – Metso Germany GmbH

Tel.: +49 (0)177 6608 485; Mail: Michael.Silvester@metso.com

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