Valves are used in the pipelines for controlling the flow of liquids and gases through them. The controlling action is done with the help of actuators which can be operated both manually and automatically.

1. Pneumatic Actuator Valves For Regulating The Flow Of Fluids In Pipelines
Valves are used in the pipelines for controlling the flow of liquids and gases through them. The
controlling action is done with the help of actuators which can be operated both manually and
automatically. When the valves are to be controlled automatically, we make use of actuators. Actuators
can be of several different types, depending on the power source it uses. They can be electric,
mechanical, electro mechanical, pneumatic, hydraulic or electro pneumatic actuators. These days
pneumatic actuators are being used extensively in oil & gas industry to regulate large valves.
Pneumatic actuators consist of piston and cylinder arrangement, very similar to the hydraulic actuators.
The only difference between the two is that they use gases instead of water or liquid. As the chances of
gases leaking from the cylinders is far more than that of liquids, a better and more efficient blowout
proof stem should be used in pneumatic actuators than what is required in their hydraulic counterparts.
The gas present in the cylinder is compressed or decompressed to exert force on the piston, and move it
up or down. This is done by forcing more gas into the cylinder to increase the pressure inside, and lift
the piston upwards. To move the piston downwards, pressure inside the cylinder is decreased by
allowing the gas to exit from the cylinder. Since, air is the most freely available gas mixture; most of the
pneumatic actuators use air.

2. The greatest advantage with pneumatic actuators is that they do not require any complex power source,
as only air is to be pumped inside the cylinder. Moreover, as air is easily available everywhere, all you
need to operate a pneumatic actuator is an air compressor. This allows such actuators to be used in
almost any mechanical activity and in any type of piping system. Also, pneumatic actuators can lift very
heavy loads, so they can be used to operate giant valves to efficiently regulate the flow of fluids in huge
piping systems. The controlling function of pneumatic actuator valves can be further enhanced by
incorporating some of the features of electric actuators. Such actuators are called electro-pneumatic
actuators, and they offer better valve regulation with the help microcontrollers. The biggest
disadvantage with such actuators is that the air compressor they require are usually very large and
bulky, which make them difficult to transport and install. Moreover, pneumatic actuators are also prone
to leakage, which would cause inefficient automation.