Main page content
Entity view (Content)
The salad factory Eisberg in Gyál was planning to expand its production line with another shaker that fills the salad mix in plastic bags.
The existing shakers, in the adjacent dilatated part of the building cause noticeable vibrations in the building structure. Since the shakers work periodically, and the perceived vibrations don’t exceed the limit for structural risk, precautions were only taken during the installation of the new shaker.
One shaker vibrates for 5 to 10 seconds and then rest for about the same time. In order to provide decent isolation, the isolators are normally tuned below the excitation frequency, otherwise no isolation can be expected. Staying below the excitation frequency, however, means that the rotation of the machine will cross the resonant frequency of the system twice in a cycle: once while speeding up and then while slowing down. In this case energy transmission can be limited by the time of the coincidence and the relative high damping of the vibration isolation bearing. The first factor is luckily guaranteed by the operation of the machine, but for the second, natural rubber-based elastomer bearings were supplied in the 200 mm high Stravifloor Jackup-R boxes. The heavy machine base compared to the proportionately light machine is also an important factor to reach satisfactory vibration isolation for the complete system.