Hydraulic solenoid valves are commonly similar to pneumatic solenoid valves apart from which they control the circulation of hydraulic fluid (oil). Hydraulic machines use solenoids to control the movement of oil. Removing the pneumatic pressure leads to the piston to maneuver downward due to the pressure in the spring. This https://pressure-gauge-wika60258.blogminds.com/everything-about-pneumatic-actuator-types-13235774