A diaphragm regulator/valve uses a flexible diaphragm as the sealing and regulating element, separated from the moving parts. This construction completely isolates the process fluid from the actuator and all moving mechanical parts, eliminating the risk of contamination and making the valve particularly suitable for sterile and hygiene-critical applications. The diaphragm regulator is a standard component in single-use systems and pharmaceutical process equipment, just as it is widely used in food and beverage production, where strict hygiene requirements apply.