Background

This case study is from a Food & Beverage plant located in Singapore, Asia. The Eastway Safeguard® online monitoring system was installed on critical production equipment in this newly built plant, between 2018 and 2020.

The Eastway Safeguard® continuous vibration monitoring system on this Turbo High Shear Mixer was installed as part of an initiative for best-in-class maintenance practices in this manufacturing site.  The plant adopted the 24/7 Safeguard® system to ensure maximum production output and reduced intrusive planned maintenance routine requirements.

The Eastway team brought their significant experience in this specialist high shear mixing equipment to the project planning and subsequent system commissioning. The Eastway team ensured the optimum sensors were selected, that the sensors were positioned to ensure early detection of all failure modes could be detected and that the machine sampling would match the on/off and varying load nature of this production equipment.  

Case Description

In March 2019 high vibration values, both Velocity (mm/s RMS) and Acceleration (g RMS), were detected above warning levels across the Mixer Turbo Shaft test points through the online vibration system. See Figure 1 for the Turbo Shaft DE Velocity Trend from 31 Dec 2018 to 01 July 2019 showing this increase in trend. Automatic alerts were sent to key personnel and the Eastway team.

Machine Name High Shear Mixer
Description Motor Belts Pulleys Turbo Shaft
kW 315
Motor Plate RPM 1488
NDE Bearing 6319C3
DE Bearing 6319C3

Figure 1 Turbo Shaft DE Velocity Trend from 31 Dec 2018 to 01 July 2019

After discussion with the plant maintenance team, it was decided to continue to monitor the machine trends for further changes.  In June 2019, an escalation of the vibration magnitudes on the Turbo Shaft, primarily at the NDE closest to the Mixer paddles, was detected. See Figure 2 for the Turbo Shaft NDE Velocity Trend from 31 Dec 2018 to 01 July 2019. On investigation the Eastway team found low frequency vibration dominant in the vibration spectra.

Figure 2 Turbo Shaft NDE Velocity Trend from 01 Dec 2018 to 01 July 2019

The plant maintenance team investigated the Mixer paddles and found a Scrapper to be damaged.

After replacement of the damaged Scrapper in Jul 2019, these low frequency vibration Velocity values seen in Figures 1 and 2 decreased significantly and remained low, see Figure 3.

Figure 3 Turbo Shaft NDE Velocity Trend from 31 Dec 2018 to 01 Oct 2019

However, despite an improvement in Velocity vibration (mm/s RMS), continued high frequency Acceleration (g RMS) values were observed through the Safeguard® Online Vibration System. Hence the condition of the High Shear Mixer remained a concern. See Figure 4 for the Turbo Shaft NDE Acceleration Trend for the same period as Figure 3.

Figure 4 Turbo Shaft NDE Acceleration Trend from 31 Dec 2018 to 01 Oct 2019

Automatic alerts continued to be sent to key personnel and the Eastway team on alarm breaches. Further analysis of the online vibration data was completed by Eastway’s remote analysis team. As an example of this the Acceleration FFT’s, enveloped demodulation spectra and the Time Waveform signatures were examined. See Figure 5 for the Acceleration FFT from 27 Sept 2019.  

Figure 5 Turbo Shaft NDE Acceleration (g RMS) FFT 27 Sept 2019

Recommendation:

Based on this analysis, it was recommended to lubricate the Turbo bearings to prolong their life and monitor closely until Nov 2019 when the maintenance team planned to complete the annual swop of the Turbo shafts.

Action Taken:

The Turbo shaft was lubricated and swopped out as planned in Nov 2019, resulting in no unplanned downtime for the plant. The plant was able to continue production to this planned downtime, confident that they would be notified in advance by the Eastway Safeguard® system of any further deterioration of the turbo shaft bearings.

Following the Turbo Shaft replacement in Nov 2019, vibration levels improved significantly, and no further works were required. See Figure 6, the Acceleration vibration trend from 31 Dec 2018 to 31 Dec 2019 (post maintenance).

Figure 6 Turbo Shaft NDE Acceleration Trend from 31 Dec 2018 to 31 Dec 2019

Figure 7 Turbo Shaft NDE Acceleration FFT Waterfall from 27 Sept 2019 (rear) to 22 Jan 2020 (front) post maintenance

Results: Estimated cost savings associated with avoidance of unplanned downtime, emergency repair costs & secondary damage:

Downtime avoided: 8 hours
Downtime cost per hour €5,000
Estimated equipment cost avoided: €30,000
Total Savings: €70,000