Electric impactor - innovative at a depth of 700 metres

Impactors are used in bulk material handling to support the material flow, to loosen residues, to destroy bridging and for product jams. This user report
shows how flow problems on conveyor belts during the removal of salts in underground mining were efficiently resolved.

A knock is required as an impulse to knock off hard-to-remove adhesions on conveyor pipes and chutes. In many companies, this is still done using the tried and tested manual hammer blow. This is not only imprecise, but can also lead to damage to the systems and conveyor belts.

Technicians and maintenance staff at K+S were also faced with this challenge. This is a well-known challenge in unfavourable constellations of the bulk material, such as the tendency to stick or jam, combined with problematic surface properties of the conveyed medium.

The pneumatic impactors of the PKL series from Netter Vibration have been providing K+S with reliable and effective, but at the same time gentle cleaning for a long time, without deformed, constricted systems additionally impairing the conveying of salts. Strongly adhering, hygroscopic salts are dissolved quickly and reliably by the impact of the PKL on its impact surface.

ELECTRIC INSTEAD OF COMPRESSED AIR ADVANTAGEOUS

There is now a new version of the PKL pneumatic impactor, the ePKL. This triggers an impact by means of an electrical pulse and can therefore be used practically anywhere. In extreme cases, it can even be used in remote operating areas without a power supply, using a rechargeable battery. A compact control unit triggers one-off or regular pulses as required. In the K+S Hera mine, conveyor belts ensure that the extracted salts are transported away. Due to their hygroscopic properties, clumping and caking occurs in many places. These repeatedly lead to a variety of faults in the conveyor technology, to restrictions in the material flow and consequently to a reduction in the performance of the entire conveyor system.

K+S therefore launched a joint project with Netter Vibration to solve the problem at particularly critical points, the so-called ‘dust chutes’, a special type of hoppers for the directed transport of salts.

MECHANICALLY HIGHLY STRESSED

NCR22 pneumatic roller vibrators have been used for a long time to knock off salt deposits and to support the material flow. The very high mechanical stress unfortunately led to increased wear and costly maintenance. The use 700 metres underground with the correspondingly long distances involved resulted in corresponding maintenance costs, and in some cases there was no compressed air supply to such distant, affected parts of the system.

After careful analysis and detailed planning, K+S decided in favour of using the electric impactor, initially as part of an endurance test in comparison to the pneumatic PKL model. The primary aim was to save on the installation and maintenance of a compressed air supply, especially as electrical connections were already present on the chutes anyway.

Thanks to its robust design, the ePKL and its control unit proved to be ideally equipped for demanding underground use. It was easy to install and reliable to operate purely electrically. The directed impulse from the impact of the piston protects the chute mechanics.

An advantage is the low maintenance requirement of the device, which in this specific case is installed at transfer stations (an intersection of conveyor belts) where employees cannot be on site every day for inspection or maintenance.

According to K+S, the ePKL has been working satisfactorily since installation when removing crude salt and is only subject to general monitoring and visual inspection of the transfer station by maintenance staff at longer periodic intervals. In this way, the ePKL perfectly complements its pneumatic variants.

Read the complete article (in German) including practical examples here, published in VERFAHRENSTECHNIK 12/2024.

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