Design of smart magnetic plug

Abstract: Bosch Rexroth in Mellansel is manufacturing hydraulic motors and constantly trying to improve their products to reduce downtime for their customers. An important thing to get a reliable system is to know the condition. In a hydraulic motor, it is crucial to determine the particle contamination of the oil to determine the condition. To do so many particle sensors have been tested by Bosch Rexroth but also other related companies during the past years. To this point, no sensor has been performing good enough to replace the ordinary magnetic plug for the laboratory tests at Bosch Rexroth.  The ordinary magnetic plug is based on an openable lid that has a magnet attached to it. The lid is opened to review the particle contamination of the system. To open the lid the motor has to be stopped and a competent person needs to be present to review the particles.To ease the work for the laboratory personal and also getting one step closer to a reliable condition monitoring solution a new idea was coined by employees at Bosch Rexroth. The idea was to use a magnet outside a glass disc and by that be able to detect the particles from outside the motor. Initial testing of the idea had been performed with promising results but more development was needed. The idea has therefore been investigated and developed further in this project. This has been done in parallel with an investigation of state-of-the-art techniques available on the market. The testing showed that the new type of magnet/glass solution was performing well and was able to detect particles of different sizes. Some other interesting options were also found during the investigation of other techniques but the new magnet/glass idea was the most prominent.