For almost 160 years, D. La Porte Söhne GmbH has been manufacturing high-precision locks and fittings for the commercial vehicle and automotive industries. In the die casting foundry, 7 casting machines work simultaneously in 2-shift operation. To prevent the parts from sticking in the tools, they are wetted with a fine spray of cooling lubricants or release oil. Fine aerosols and oil mist are released and remain in the hall air until they are deposited on floors, walls and surfaces as a fine oil film.

The challenge

In a hall, the released oil vapors and aerosols from 4 casting machines, which work simultaneously and in 2-shift operation, are to be extracted. In order to comply with the applicable workplace regulations, these harmful particles must also be reliably filtered out of the hall air.

As is typical for the industry, die casting machines generate a lot of heat. Therefore, the hall is to be continuously supplied with fresh air and the extraction unit is to run in exhaust air mode instead of recirculation mode. DLP had already installed another extraction unit with an electrostatic filter in recirculation mode and was still dissatisfied with the separation performance and air quality. The filters were quickly clogged and had to be cleaned frequently, which was something that had to be prevented during the technical planning of the new solution.

The extraction solution

An E 4000 series oil mist separator with an air flow rate of 7,200 m³/h captures the fine oil particles and aerosols via 8 slotted hoods and filters the emissions from the production air via 3 filter stages.

The oily air is extracted from the hoods, flows into the extraction unit via a piping system and first passes through two filter stages made of stainless steel mesh, where a large part of the release agent is already separated. These drip off the knitted fabric and collect in a discharge container. The process air is then finally cleaned via 4 class E11 cassette filters.

Filter stage 1
2 Stainless steel mesh filter

Filter stage 2
2 Stainless steel mesh filter

Filter stage 3
4 Cassette filter

The cleaned process air is then led outside as clean exhaust air via a piping system. The separated lubricants are collected in a discharge tank, which is connected to the system via a ball valve incl. a drain valve. Siphon has and can be drained and reused if necessary.

1 year without filter cleaning?
Even the first filter stage is so effective that our customer has not had to clean the metal mesh filters even after one year of operation, and the cassette filters are still absolutely as good as new. The filter performance is continuously monitored by a differential pressure sensor and has only decreased by approx. 2% after one year.

In general, all metal mesh filters from ABSAUGWERK are made of stainless steel and can be washed out with a conventional high-pressure cleaner and used again and again.

Fresh breeze in production
To significantly improve the air quality and cool the hall, the hall air should also be enriched with fresh air. These fresh air systems are usually separate and are placed next to the extraction unit. To save space and costs, our technical manager Martin Prokisch has created a customized solution and integrated the fresh air box into the extraction unit – 2 in 1.