Valves are devices used to close outlets, openings and to regulate fluid flow and pressure. There are two types of valves, namely piston and ball. Depending on the purpose, the valves are divided into: check, control, closing, safety, distributing, butterfly, tap, diaphragm, needle, gate and screen. The task of the servo valve is to control the flow of hydraulic fluid to the actuator. It allows very precise regulation of speed, position, strength and pressure.