Problem solving

Motor vehicle construction: Precautions against highly flammable dusts

Wet separator makes flammable aluminium and magnesium dusts harmless

Pierburg GmbH has installed an Ex-protection extraction plant with a wet separator at its works in Nettetal. The company is part of Kolbenschmidt Pierburg AG, a group with over 11,000 employees worldwide and makers of modules and systems for motor vehicle engines. At Nettetal the company produces a magnesium suction pipe. Manufacturing is highly automated at Pierburg but some pre-series and prototype parts made from magnesium are worked by hand. This is done at a special workstation where the fine and very reactive (i.e. inflammable) magnesium dust is extracted at source by extraction nozzles. The job of extraction in this case is entrusted to a mobile Ruwac Type NA 35 wet separator.

The very compact NA 35 is one of the latest developments from Ruwac. Waste material is vacuumed into the wet separator module where it is bound to a fluid medium. There is a filter system downstream from the wet separator. The Ex-proof NA 35 is also fitted with a gas venting valve as specified in safety directives.

The NA 35 provides Pierburg with a particularly flexible machine. The vacuum unit can be used as a mobile unit away from the workstation and is ideal for cleaning floors and machines.

Pierburg is very satisfied with the new vacuums. Performance and safety features meet company expectations to the full. This comes as no surprise to the Ruwac users in Pierburg's model workshop in Neuss. For years they have been using a Ruwac extraction unit for an identical application.

In Neuss a fixed extraction unit is used. Here, the Pierburg workshop processes a wide range of materials and has therefore opted for a "two-way" solution developed in collaboration with Ruwac. The system has two extractor arms each painted a different colour. When the machine operator is working with non-explosive materials, the blue extractor arm is swung into position and the process dust is vacuumed directly into a Ruwac type DS 2720 B1 vacuum. If, on the other hand, magnesium is being machined, the operator will switch in the red extractor arm using a three-way valve. In this case the dust is drawn into a Ruwac wet separator. In the separator, the extracted material is fed through a submerged pipe into a fluid. Any particles which are not trapped in the separator are stopped by a fine filter located downstream.

The vacuum unit is in a neighbouring room. The vacuum unit, the wet separator and the NA 35 are certified for use in Type 1 explosion zones and certified to German regulations BGR 204 ("Handling Magnesium") and BGR 109 ("Directives for preventing dust explosions when sanding, brushing and polishing aluminium and aluminium alloys). All system components are suitable for separating magnesium and aluminium. The DS 2720 B1 is a powerful AC vacuum ideal for continuous operation. The very large filter gives it a long service life. Ruwac's long experience in the development and construction of industrial vacuums for use in explosion hazards zones is a sure guarantee that the company can always provide practical, cost-effective and safe solutions. Ruwac's experience and expertise are built into the NA 35.