Air actuators isolate disruptive vibrations in screening machines
05 May 2017
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.
In general, vibrating screens are powered by shafts with unbalanced weights, unbalanced motors, or exciters and are thus caused to move in a defined manner. The vibrations that occur during this process are transmitted to the structure of the screening system as well. This has considerable consequences as the steel structure and the add-on parts start vibrating and, as a result, 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 specialised in the mounting 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 prevent the transmission of vibrations. Air actuators offer significant advantages over compression springs, leaf springs, or rubber springs. Their most striking feature is a very strong isolating effect, which – at up to 99 percent – is much higher than that of conventional spring types.
Lower energy consumption and less noise
More efficient decoupling means fewer add-on parts are caused to vibrate and thus less energy is consumed. This means lower power consumption with the same throughput, and thus a cost advantage for the operator. The improved vibration isolation also reduces the noise level, resulting in a healthier working environment. There is also a reduction in structure-borne noise, which can be transmitted over a number of miles. This increases the general public's acceptance of the system.
Control element balances out differences in height
Another major benefit of air actuators is that their internal pressure can be regulated. For use in screening machines in particular, this characteristic offers new opportunities to further optimise the screening process. ContiTech and LuCoTec therefore joined forces with partner company CFM Schiller to develop a new patented control unit. This product enables fully automatic regulation of internal spring pressure, which allows the screening system to adapt flexibly to different load states and balance out differences in height.
Nicolas Morr, development engineer at LuCoTec, said the dewatering of sand is a typical practical example that illustrates how important this function is in practice. During processing, sand can sometimes be drier and sometimes wetter. The following rule applies here: the wetter the sand, the greater the weight on the screening system's input side. By coupling the input and output sides and automatically regulating the internal pressure in the air actuators, the control unit balances out this difference in height.
Morr explains that no matter what material the screening system is loaded with, it achieves comparable throughput thanks to the new control unit. This constitutes a milestone in screening technology – one that would not have been so easy to achieve with fixed steel springs.
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