A pneumatic machine is one that is driven by compressed air. If no other forces are acting on them, the molecules in gases, such as air, spread out to fill the space that is available to them. If the space is sealed and then reduced, the air is compressed — the molecules are pushed closer together. This means that the pressure that the compressed air exerts on the inside of its container is greater than the atmospheric pressure pushing down on the outside of the container. A pneumatic drill, also known as an air-hammer or jack-hammer, uses compressed air to push its bit forcefully against the ground being broken up. The compressed air is supplied to the drill through a hose by a machine called a compressor.
A pneumatic system is a collection of interconnected components using compressed air to do work for automated equipment. Examples can be found in industrial manufacturing, a home garage or a dentist office. This work is produced in the form of linear or rotary motion. The compressed air or pressurized gas is usually filtered and dried to protect the cylinders, actuators, tools and bladders performing the work. Some applications require a lubrication device that adds an oil mist to the closed pressurized system.
Pneumatics is an application of fluid power—in this case the use of a gaseous media under pressure to generate, transmit and control power; typically using compressed gas such as air at a pressure of 60 to 120 pounds per square inch (PSI). Hydraulics is another form of fluid power, which uses a liquid media such as oil but at a much higher pressure with a typical range of 800 to 5000 PSI.
A big reason pneumatics are used is due to simplicity. With little experience, on-off control of machines and equipment can be designed and assembled quickly using pneumatic components such as valves and cylinders. With proper air preparation, pneumatics systems are also reliable, providing a long service life with little maintenance needed.
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