Humidity, extreme heat or cold cannot stop corrosion-protected pneumatic components – they are unaffected by temperatures between -20 and +80°C, while special low-temperature variants can even operate down to -40°C  and high-temperature variants up to +120°C. All stainless-steel component variants are extremely resistant to corrosion.

Simply uncomplicated
Pneumatics is an uncomplicated technology which is easy to install, since it requires no monitoring or sensing functions apart from end-position sensing and monitoring of the compressed air supply. Totally true to the motto “Fit and forget”.

Energy-efficient: Pneumatic actuators operate directly on a shut-off device while electric drives convert part of the energy into heat. (Photo: Festo).

Pneumatic drives have proved to be vibration-resistant and long-lasting. In contrast to electric drives, they consist of only a few components and are thus less susceptible to breakdowns. What is more, pneumatic drives are able to withstand continuous load and require no maintenance throughout their working life. There is no need for oil changes or lubrication top-ups.

Down with costs
Thanks to the lower costs, it is even worthwhile to automate manually operated valves retrospectively. Particularly in comparison with electric drive technology, the broad-based use of decentral automation concepts with valve terminals results in considerable cost advantages: savings of more than 50 % are possible in some cases.

Energy-efficient solutions
Pneumatic drives require electricity only for control functions and to generate compressed air, while their actual motion is created by compressed air. While with electric drives part of the energy with which they are supplied is converted into heat and lost in gear units, pneumatic actuators operate directly on a shut-off device. They only require a piston and a drive shaft to convert the “linear” energy of compressed air into a swivel motion.

As pneumatic drives are overload-tolerant and allow higher drive forces to be achieved simply by increasing the supply pressure, it is often possible to use smaller drives with lower weight than would be possible with electric drives. Provided that the tubing connections are leak-free and components are correctly dimensioned, the result is energy-efficient solutions. Pneumatic systems from Festo can deliver high forces of up to 50,000 N and torques of up to 10,000 Nm.

Emphasis on safety
Pneumatic drives have three emergency functions in the event of a power failure – open, close and stop – and allow low operating pressures. They are ideal for use in areas with a potentially explosive atmosphere, in particular when explosion-proof valves, such as NAMUR valves with appropriate coils, are used and the valves or valve terminals are located outside the explosion-hazard zone.

In these cases, the pneumatic drives in the explosion-hazard zone are supplied with compressed air via tubing, while the electrical control components can be installed in a non-hazardous zone. Pneumatic drives are ATEX-approved as standard up to zone 1.

Indestructible: With of more than 1 million operating cycles, pneumatic actuators will outlive any process valve.
(Photo: Festo)

Overload tolerance
Deposits or baked-on residues of foreign material can lead to considerably higher breakaway forces of pneumatic drives. This happens particularly when valves are actuated irregularly or not for long periods, as is the case, for example, in sewage treatment plants. The overload tolerance of pneumatic drives is a great advantage, as with pneumatics it is not a problem to increase the operating pressure and thus obtain higher forces. They will not suffer damage even if overloaded to the point where they come to a standstill and have large reserves of force for cases where high breakaway torque is required.

Competent and relevant advice
Festo experts can help with the calculation of compressed air consumption and the optimum dimensioning of compressed air supply networks; they can also provide assistance during the tendering phase if required. Customers can obtain everything they need from a single source and with just one part number – this ensures a simple ordering process and means that projects can be completed more quickly.

This article is part one of a three-part monthly series on Process Automation, to be continued next month. It was contributed by Festo Canada (www.festo.ca).