Magnetic filters in cooling water circuits
A large automobile manufacturer uses die-casting machines to produce engine and transmission components. Due to the size of the molds and the machines, up to three temperature control units are used per die casting machine. The cooling water flow is controlled in the temperature control units using small flow meters with turbine impellers.
Problem
During operation, there were repeated error messages due to a lack of cooling water, resulting in production stoppages. A detailed inspection revealed that the cooling water flow was completely fine.
The cause of the error messages was very fine dirt particles that had become lodged in the area of the flow meter turbine. This prevented the turbine from running freely and the measurement result was incorrect. For this reason, the flowmeters had to be replaced after only approx. 2000 operating hours.
The turbines usually have a service life of over ten years. In total, the annual costs for repairing and replacing the flow meters amounted to around €40,000.00 per year.
Due to the high operating costs, the maintenance department, together with the manufacturer of the temperature control units, looked for a way to reduce these costs. Due to the dirt deposits, they quickly became convinced that effective filtration of the cooling water could reduce the running costs.
Solution: FMF 240/1 HT magnetic filter
FMF 240/1 HT magnetic filter
The manufacturer of the temperature control units came into contact with Friess GmbH following an internet search.
After an initial analysis of the situation, two FMF 240/1 HT (high temperature) magnetic filters were installed in the internal machine cooling circuit of a die casting machine.
After approx. 2 weeks of operation, the magnetic filters were opened for the first time. Although the cooling water did not look particularly dirty at first glance, the magnetic filter rods were clearly contaminated with ferritic particles.
After a further two weeks of use, the magnetic filter rods were again contaminated with particles.
Although it is a closed circuit, it is obvious that new particles were constantly entering the cooling water.
The cause of the particle contamination turned out to be corrosion in the cooling channels of the molds used.
By continuously removing the ferritic particles, the cooling water is significantly cleaner. The turbines in the flow meters are now in use for well over 2000 hours.
As the particles removed by the magnetic filters had not been captured by the filters installed in the temperature control unit, it is planned to retrofit the individual cooling water circuits with magnetic filters in a temperature-resistant design.
Results of magnetic filters in cooling water circuits summarized:
- the cooling water is less contaminated due to the continuous removal of ferritic particles
- the turbines in the flow meters are now in use for well over 2000 hours
- annual costs for repair and replacement of the flow meters have been significantly reduced