Problem solving

Recycling lubricants

Oil extraction and treatment during chain production

For a long time it has seemed that belt drives are about to replace good old-fashioned chain drives. But it is not to be. Car engine manufacturers, among others, seem to prefer chain drives more than ever. This is good news for IWIS J. Winklhofer & Söhne GmbH & Co. KG in Munich, a leading manufacturer of high-performance roller chains.

For IWIS, RUWAC has developed an oil mist extraction unit tailored to the precise requirements of the chain manufacturing process.

In the last stage of the production cycle before packing and despatch, IWIS immerses its chains in an ultrasound oil bath. The oil is warmed beforehand to 75°C to ensure that the lubricant reaches all the awkward places in the chain links and stays there.

When the chains leave the bath, the surplus hot oil has to be removed. Not the easiest of jobs in terms of process technology.
After a lot of development work and practical tests, RUWAC proposed the following solution. When the chain leaves the bath, the surplus oil is blown off with compressed air and a suction unit extracts the oily air. The extracted oil mist is cooled in an oil bath to remove some of the oil.

The air pre-cleaned in this way still contains a lot of oil and must be passed through the demister mat of another pre-separator to remove remaining oil particles. In the third step of the treatment process, the air is passed through a Class C bag filter whose filter surfaces are coated with an oil repellent.

These three treatment steps serve mainly to separate out as much oil as possible before the air reaches the oil separator and the oil mist filter cartridges downstream. This design reduces the load on the filter cartridges; the cartridges have a total filter surface area of 10 m².

At the end of filtering, the air is so clean that it can be fed out without further treatment. The separation cycle produces 6 to 7 litres of oil per hour. A submersible pump installed in the collection tank, pumps the separated oil back into the original oil bath.

RUWAC invested a lot of its expertise in this customised project. However, the project required more than just a good knowledge of the separation methods involved. These methods are, after all, widely known and used with success. What the project did require was a lot of engineering experience and expertise. The experience and expertise to choose the right stepwise treatment procedure and to decide the specifications and dimensions of the individual extraction system components to be used. Cost-effectiveness was a decisive factor in choosing this particular solution. Much detailed work went into ensuring that the service times between filter changes in all the process steps were as long as possible.

Fine tuning the solution adopted has been well worth it. After a long test period with the first unit, IWIS is so satisfied with results that it has already ordered another RUWAC extraction system.