The new valves can be adjusted and set externally during operation, for liquid and gaseous media, service friendly due to replacement cartridge. This overflow valve made of high-alloyed stainless steel combines all of these advantages. According to the sealing- and diaphragm materials employed, these valves can be used for neutral and non-neutral media. It can be used for protection of pumps against overloading in closed circuits for neutral / non-neutral, non-sticking liquids. And also for the control of systems under pressure for air, neutral / non-neutral gases and vapours, industrial plants, power plant technology, pump systems, mechanical engineering and secondary areas in the food-, beverage-, pharmaceutical- and cosmetics-industries.