Vibration Screens

Vibration screens are used for separation of matter according to their sizes, and they’re especially important in mining processes. The machinery is basically formed by a motor, exciter mechanisms, bearings, sieve screen mesh and vibration attenuators. The functioning happens with a precise vibration movement on an adequate inclination angle, which provides benefits like energy economy and reduction of costs in screening processes.

Various components of a vibration screen can present faults, that can lead to repairs, downtime and various costs. The implementation of a continuous monitoring system for fault detection and other predictive maintenance strategies are fundamental for increasing the safety and reliability of this machinery.

Although the whole system has several vibration loads, which are inherent to the process and its components, still it is possible to relate those loads to specific parts of the machinery or process that the machinery goes through. For example, harmonic loads are related to vibrational isolation present in vibration sieves or even transient vibrations can appear because of an impact/impulse of charging over the sieve.

In this sense, an assertive monitoring of vibrational behavior from the installation of vibration sensors can play a role in the reliability of these assets . However, wired systems, when they’re installed at this type of machinery, usually result in high costs of maintenance in cables and infrastructure. Thus, there are huge advantages in the application of wireless sensors, with low or without maintenance costs, easy installation, automated (with gateway assistance) and continuous monitoring, among others.

In order to obtain good results with wireless vibration sensors, some care must be taken, like choosing the right sensor, correctly positioning (mounting) it at the components to be monitored and doing an adequate operation configuration.

At the vibration screen monitoring, two Dynamox sensor models are most used: DynaLogger TcA+ and DynaLogger HF. DynaLoggers TcA+ are recommended for springs or suspension system monitoring. For the DynaLogger HF it is recommended the installation at two points on the electric motor (i.e. drive end and non-drive end) and on  the bearing casings at the eccentric shaft. The figure below shows an example of a screen model, where the white dots represent the DynaLogger TcA+ model, and the blue dots the DynaLogger HF model. 

It is important to mount DynaLoggers on all bearing housings or rigid parts for effective monitoring. Avoid mounting sensors on flexible surfaces, on curves or that have localized resonance such as protective covers and fins.

(It is recommended to install on both sides of the vibrating screen, placing TcA+ sensors in all the fixing points of the suspension)