|
Because of the
compressibility of air, speed control of large pneumatic actuator
may become difficult. In instances where the valve torque variation
is large, negative (overrunning torque) or the valve disc has high
moment of inertia, pneumatic actuator may exhibit jerky motion. When
the cost of a hydraulic power unit cannot be justified, and air is
readily available, Air over Oil System is a solution to this
problem. Additionally, the presence of oil reduces possible
leakage of air (or gas) from the system. Air over Oil System is
widely used in Gas Pipe Line Actuators where the gas from the
pipeline is used as the power source. The system can also be
designed to sense pipe line breakage and shut down the actuators on
such emergencies.
In Air over Oil
System, the air or gas is fed to two air over tanks where oil is
stored. The actuators are hydraulic type.
Several design
criteria should be met to obtain satisfactory performance for such a
system. Consult us with your specific requirements.
CLICK HERE FOR
PICTURES
|
