The difference between hydraulic valves and pneumatic valves

 Both the pressure valve and the pneumatic valve can realize the opening and closing of the valve door. The pneumatic valve is mainly used to move the two pistons toward the two ends of the cylinder separately when the air source enters the cavity between the two pistons of the cylinder. The air in the two air chambers is discharged through the other air port, and the two piston racks simultaneously drive the output shaft ( Gear) rotate counterclockwise. Make the valve door open and close. The hydraulic valve gate passes through the hydraulic oil principle as above.
What is the difference between pneumatic valves and hydraulic valves? The following Dalan Hydraulics editor gives us an analysis: the working pressure scale of pneumatic valves with different pressure scales is lower than that of hydraulic valves. The working pressure of pneumatic valves is usually within 10bar, and a few can reach within 40bar. But the working pressure of hydraulic valves is very high (usually within 50Mpa). If the pneumatic valve is used at a pressure exceeding the maximum allowable pressure. Serious accidents often occur.

Requirements for leakage: Different hydraulic valves have strict requirements for external leakage, but allow for a small number of leakage inside the components. For pneumatic control valves, except for gap-sealed valves, internal leakage is not allowed in principle. The internal leakage of the pneumatic valve has the risk of causing an accident. For pneumatic pipelines, a small amount of leakage is allowed; and the leakage of hydraulic pipelines will cause a drop in system pressure and pollution to the environment.