Metallic surface coating of workpieces and objects is generally performed to protect them from corrosion or wear. However, coatings can also be used to achieve certain functional characteristics, such as electrical conductivity, or may also be applied with the aim of producing visually attractive surfaces. In electroplating plants, workpieces are dipped into various process baths for this purpose. The different stages of the process consist of pre-treatment, metallisation and posttreatment. Ion exchangers are often used in electroplating plants to treat raw water for production purposes or to bind the substances contained in the various types of rinse water so that clean water can be fed back into the process. However, ion exchangers are also used in waste water treatment as the last stage of cleaning before the cleaned waste water can be fed into the local sewerage system. Flow optimised GEMÜ R690 diaphragm valves and robust GEMÜ 800 fl owmeters are used both in the upstream gravel filtration plants and in the ion exchangers operated by PWM Service GmbH.