OREANDA-NEWS. Even in harsh conditions involving a lot of dust and permanent vibrations, air actuators continue to work reliably. They isolate vibrations in construction machinery and are robust and resistant even in adverse environments. “With these properties, they offer added value compared with steel spring bearings or hydraulic cylinders, as disruptive vibrations are largely minimized,” said Verena Weiss, head of industry at ContiTech Air Spring Systems. At the bauma trade fair in Munich, ContiTech is presenting the advantages of air actuators for the construction industry based on a range of use cases. 

Fewer shocks from vibrating screens

Whether in the mining industry or at a gravel plant, vibrating screens are used in processing plants to separate raw materials according to size and to filter out unwanted elements. The vibrations that occur during this process are transmitted to the steel structure of the vibrating screen, with the result that all components are placed under additional load.

ContiTech air actuators help to significantly reduce vibrations in the steel structure of the processing plant. The company LuCoTec, which has specialized in vibration isolation of screening machines and processing plants, successfully uses ContiTech air actuators for this challenging task. Installed between the vibrating screen and the steel substructure, they decouple these two plant components and effectively prevent the transmission of vibrations.

Air actuators offers significant advantages over compression springs, leaf springs or rubber springs. The most striking feature is the low natural frequency in a range of between 1.5 and 3 Hertz. This allows the air actuators to achieve a strong isolating effect of up to 98%. In comparison, steel springs in screening machines usually have a natural frequency of 7 to 8 Hertz and an isolating effect between 65% and 75%. 

For use in vibrating screens in particular, the ability to regulate the internal pressure of the ContiTech air actuators is a significant advantage. This enables flexible adaptation to different load states. To this end, LuCoTec has developed a patented procedure with which the screening process is optimized using ContiTech air actuators.

More efficient decoupling means fewer neighboring parts are caused to vibrate and less energy is consumed – while the same throughput is maintained. The improved vibration isolation also reduces the noise level, resulting in a healthier working environment.

Greater productivity, less noise

Hydraulic hammers are used to break down rocks in quarries as well as in road and tunnel construction. They consist of a housing, a striking mechanism and a chisel, which fits in the housing. The principle of operation: the oil pressure provided by the supplying device – usually an excavator – is converted into kinetic energy through a hydraulic cylinder and then transmitted to the chisel.

If an air actuator is also used in this application, the impact of the striking mechanism on the chisel is cushioned. This means an increased frequency of 1,000 to 1,500 impacts per minute can be achieved at forces of between 30 to 80 metric tons. As a result, productivity increases by up to 80% compared with conventional hydraulic hammers.

In addition, air actuators in hydraulic hammers reduce the noise level by up to 25 dB and isolate vibrations, with the result that the machine operator is exposed to weaker vibrations – a plus point when it comes to occupational health and safety. Another advantage: Hydraulic hammers equipped with air actuators can also be used under water, for example in port or canal construction.