Vibration analysis online is the natural evolution of vibration analysis. Vibration analysis was first applied by the use of portable data collectors and data recording gathered from the route. Depending on the condition monitoring program, the manual data was collected periodically from 2 weeks to 6 months. With technology changes, the need to monitor machine status more closely and even to get data continuously is increasingly common.
Online vibration monitoring systems were developed for this need. Their performance is at least equivalent or superior to portable systems. However their main advantage is the ability to access data at any time. Wireless vibration monitoring removes some of the major drawbacks of previous systems such as time and installation costs associated with a wired system. A wireless online condition monitoring system offers the possibility to extend your predictive maintenance strategy to the complete plant where wired systems typically protect production assets.
The following case study describes and explains a typical remote analysis application of continuous friction/lubrication monitoring on a fan assembly. The continuous surveillance was set up in a very effective way for the customer and analyst.
Equipment, plant overview, Context
The Chemical site is a Phosphoric Acid Plant operating 24 Hours 7 days a week, established for many years in Africa. The Equipment in question is a large mixer involved in the acid production and a very large fan for production air treatment.
Routine measurement performed with portable data collector indicated friction on both of these machines bearings. Cage frequency issues were detected, indicating higher than normal levels of friction. These raised levels would not warrant an immediate replacement but the next planned shutdown was in 10 months time.
I-Care suggested the installation of Wi-care wireless vibration/temperature monitoring system and the analysis/trending by its remote team to ensure no premature escalation in the evolution of the defect.
The Wi-care system is set up with two sensors, one on the bearing supporting the coupling disc and one on the fan bearing wheel side.
Displayed below is the standard spectrum collected with the Wi-care wireless monitoring system on vertical direction on fan bearing. Display in acceleration unit G PK.
The spectrum shows a random noise vibration indicating friction inside the bearing. Some peaks (including the dominant one at 375 Hz) are related to ball frequency. The level of friction is low (3 times lower than 6 months before).
Wi-care data from May 2014.
Below is the spectrum in acceleration and analysis collected and analysed 6 months prior (at the time the friction issue was discovered). Levels of friction in the spectrum are high. Following on from this measurement it was decided to regrease the bearing and to install a Wi-care wireless sensor to follow the evolution of bearing friction.
Portable analyzer data collection- October 2013
Analyst observations :
Similar spectrum behavior in 2014 with Wi-care and in 2013 with portable collector although the level of friction has been divided by 3 by improved lubrication monitoring.
The friction issue is easily identified with the portable data collector and the Wi-care wireless (even though the levels are 3 times lower after lubrication.) The close trending of bearing lubrication (greasing) based on Wi-care monitoring vastly reduced the level of vibration and ensured a much more effective trending of the friction issue.