Solenoid valves are used mostly for clean media such as liquids or gases. For the solenoid valves we distinguish between pilot solenoid valves and process solenoid valves. Pilot valves are used for piloting pneumatic valve actuators. For this purpose media such as filtered, lubricated or oil-free compressed air and inert, gaseous fluids can be used. Process solenoid valves are used directly in the process, e.g. as in dosing.