New safety system for the HUBER Sludge Turner SOLSTICE®

The new redesign machine SOLSTICE® 11 in operation for the first time

Redesign reduces the hazard potential

Whether we develop new products or redesign existing machines, we always do this considering also the safety aspects that are important to minimise the hazard potentials when handling our products as required by the Machinery Directive.

How important it is to pay special attention to product safety could be seen only last year on a competitor’s solar sewage sludge dryer installation in Bavaria where a tragic accident happened. This was even more reason for us to once again look very thoroughly at our safety systems and further improve them.

When we recently redesigned the HUBER Sludge Turner SOLSTICE®, we completely revised the safety system of the entire sewage sludge drying plant.

The HUBER Sludge Turner SOLSTICE® is the innovative heart of the solar sewage sludge dryer and operates in a greenhouse both as a sludge turning and sludge transporting system for the sludge to be dried. Depending on the different specific conditions on site (throughput, air moisture, inside and outside temperature, ...), the especially developed control unit controls the travel and rotation of the HUBER Sludge Turner SOLSTICE®.

The new feature of the safety concept is that the access to the operating area of the automatically operating machine is consistently monitored electronically. Whenever somebody walks into this area, the machine will be shut down by the emergency circuit. This prevents severe injury. It was further of great importance for us to ensure that the safety devices cannot be bypassed and will not be perceived as uncomfortable or disturbing. Their new design is therefore still very functional and user-friendly.

The new SOLSTICE® 11 turning sludge at Zhenjiang, China

The entrance area where the wet sludge is fed is equipped with a 3-beam light grid that allows the operator to directly inspect the machine any time without interrupting the operation cycle of the HUBER Sludge Turner SOLSTICE®. Feeding the sludge with a wheel loader is safe and easy. The interface between the man-operated machine (wheel loader) and the automated movement of the sludge turner is controlled by the light grid. The wheel loader can drive directly into the operating area and bring in sludge without having to remove fences or similar installations before. It is at the same time ensured that the HUBER Sludge Turner SOLSTICE ® does not start to move.

The rear gates and the maintenance doors are equipped with monitoring sensors. When the doors or gates are opened, the emergency circuit will be interrupted. Signs are additionally mounted at all mechanical entrances to warn of potential hazards.

The new safety system will be applied for the first time in the project Denizli in Turkey, the biggest solar sewage sludge drying project by now that will be equipped with HUBER machines. An annual amount of 25,000 t press sludge will be dried on the Denizli site in the future by 8 HUBER Sludge Turner SOLSTICE® units, size 11. The second project where the new safety system will be used is not 2,000 km away like Denizli but only 10 km from the HUBER headquarters, on STP Freystadt. A solar sewage sludge drying plant will be built there for which HUBER will supply a complete solution.