The Importance of Checking the Amplitude of a Vibrating Screen
| October 23rd, 2018
Was there ever a time when mining equipment was primitive? Presumably so, but that time has long since vanished into the past. Take vibrating screens as one example of the modern era. The screens don’t simply quiver and shake at random. On the contrary, the technologically advanced vibrational mechanisms oscillate in a precisely controlled manner. There are even oscillating waveforms attached to the vibrating decks, which have special operational signatures.
Exploring Sinusoidal Curves
Every engineering branch recognizes waveform science. In mining equipment applications, it’s the vibrational oscillations utilized by the aggregate-vibrating decks that we associate with this science. Wave frequency, the speed at which the vibrations are generated, is an easy enough property to discern. For pure dynamic effect, however, it’s the amplitude, the peak height of each oscillating wave that concerns an engineer. High and narrow, the amplitude of the equipment generates an elliptical screening effect. Moderated and averaged, smaller peak amplitudes produce circular sieving action while a near flat waveform results in motion that is used to yield linear screening motion.
Checking Screening Amplitude
Away from the theoretical point of view, the site engineering team inspects the screening equipment. The speed or frequency of the deck is set just-so, but the dynamic action seems off somehow. The rotational energy thrown out by powerful motors will require checking, but that’s a purely circular energy constant, not one that generates wave amplitude. Next, before going further, the inclination of the deck is measured. Deck angles transform plain circular waveforms into elliptical action, so this stage of the proceedings is important. Finally, the counterweights and any coupled assemblies receive an in-depth maintenance check.
Assessing the Adjustable Counterweights
The motors and deck inclination are easily determined. It’s a little harder to inspect the counterweights, though. They’re adjustable, which makes sense when different aggregate types and sizes are expected to challenge the mining equipment. Inspect system bearings here, plus all adjustable fasteners and hinged or spring-loaded components. Moreover, do closely examine the mechanical components, for these parts are exposed to significant quantities of kinetic stress. They age and experience wear. When that happens, their amplitude regulating features can and often do go awry.
Last of all, to really measure screening amplitude properly, there are tools and kits available. They attach to the equipment at a predetermined point, usually on the side of the deck, where they’re then configured. From here, the amplitude, displacement metrics, and vibratory stroke length can all be observed and manually regulated. Remember, it’s the characteristics of the aggregate that decide amplitude strength. Set too high, this value could shake the machinery apart. Even as a best-case scenario, a higher than average waveform amplitude will severely shorten the lifespan of the screening deck.