Pneumatic and Electropneumatic Controls

Advantages and Disadvantages of using Pneumatic Systems

Compared to other drive technologies (electro)pneumatic systems demonstrate a series of advantages as well as some disadvantages:

Availability: air is available for compression almost anywhere in a practically unlimited supply.

Transport: compressed air can be easily transported in pipes over long distances. No return pipe is needed.

Storage: compressed air can be stored in a container. Even transport in bottles is possible.

Temperature: compressed air is insensitive to temperature fluctuations. Thus its use can be guaranteed in even under the most extreme conditions.

Explosion-proof: compressed air can also be used in areas where there is a risk of explosion .

Cleanliness: leaking pipes, hoses or pneumatic elements do not cause any contamination due to the escaping air. An important plus in such areas as the food or textile industry.

Speed: with compressed air relatively high operating speeds of up to 2 m/s can be achieved in pneumatic cylinders.

Controllability: the forces exerted by pneumatic actuators and their speed can be continuously adjusted.

Very good load capacity: compressed air tools and actuators can be loaded up to standstill and are thus extremely capable of handling  heavy loads.

Preparation: compressed air requires good preparation. Dirt and damp must be kept out of the systems as otherwise this subjects the pneumatic elements to undue depreciation.

Compressibility: it is impossible to attain uniform and constant piston speeds using  compressed air.

Forces: compressed air is only economically viable up to a certain expenditure of force. The traditional operating pressure is normally around approx. 7 bars.

Air exhaust: the air exhaust that is generated causes relatively loud noise. This problem can be mitigated to a large extent using sound insulation.

Costs: compressed air is a relatively expensive energy source. However, these costs can be somewhat offset by the relatively low cost of the pneumatic components and their high performance (timing rates).

Differences between Pneumatic and Electropneumatic controls

Pneumatic and electropneumatic controls both feature a pneumatic power component which is comprised of the following components

Actuators (directional control valves, which are electrically actuated in the case of electropneumatic controls)

Working elements (cylinders, pneumatic motors, optical displays)

The signal control component (consisting of signal inputs and processing elements) is designed differently:

In a pneumatic control system, control is achieved by pneumatic components such as various types of valve, air-distribution routers, sequencers etc.

In an electropneumatic control system, the signal control element is designed with electrical components like electrical pushbuttons and switches, proximity switches or programmable logic controls (PLC), for example.

In both cases the directional control valves constitute the link between the power control and the signalling control elements.