Definition
Pneumatics is the field of compressed air technology which deals with doing work using compressed air (typically in pneumatic cylinders) and controlling machines used to work with this technology (via valves). This can be divided into the following areas:
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Compressed air generation delivers normal ambient air in a compressed form. This is achieved using compressors, which suction in air, then compress it in a pump and deliver it to compressed air lines (tubes or pipes). Low pressure pneumatics works within a range of approx. 100 mbar to 1 bar overpressure; at least around 6 bar overpressure is generally used to generate higher forces.
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For
compressed air preparation, air is cleaned (e.g. filtered) and may have a fine oil mist added by atomizers, to ensure continuous lubrication of movable components like valves and cylinders.
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Compressed air distribution is handled by tubes, pipes, T-connectors and similar components.
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Controlling is handled by valves, which may be actuated manually (by an operator), mechanically (by a moving machine component) or pneumatically (by the compressed air signal of another valve). There are many different kinds of valves used to switch a signal on or off (i.e. to apply compressed air to it or vent compressed air from it), for time delay and for signal storage. Throttles regulate the air flow (causing a cylinder to retract or extend slowly).
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The
actuators used in pneumatic systems are usually pneumatic cylinders. They consist primarily of a closed tube, which is divided by a tightly fitting disc inside. The cylinder rod (piston) sits on the disc. When compressed air is fed into one of the two halves of the cylinder (and air is vented out of the other), the disc and thus the cylinder piston will move. There are many different cylinder types, as well as other actuators, such as pneumatically activated counters.
Another interesting sub-field of pneumatics is fluidics: Switching and controlling systems using flowing media (gases, air or liquids). The unique thing about this type of pneumatics is that fluidic valves do not require any moving parts for logic circuits; instead, they function solely through the targeted shaping of flow channels. The pressure is not the key signal, but rather the flow of the medium. Pneumatic fluidic systems work with a pressure of just 100mbar, require no oil for lubrication, and result in valves that are self-cleaning thanks to the high flow speed. Fluidic signals are only converted into standard pneumatics or electrical systems if the controller ultimately requires a large force.
Pneumatics is related to the physics fields of mechanics, kinematics and thermodynamics (compressed air becomes warm), and fluid mechanics, as well as the mathematical field of logics for logistics circuits in pneumatic controllers, and therefore Boolean algebra.
