Modern real-time monitoring allowed this plant to drastically improve its reliability strategy.
by Matt Cowen

Motor-driven roots blowers are a critical part of everyday operations for one of the nation’s leading chemical companies, which creates chemical components for vehicle tires. Unexpected failures in the roots blower parts have cost the plant up to $80,000 in lost productivity for one specific incident.

When a leaky seal on one of the plant’s 10 roots blowers was causing shutdowns, the reliability manager ramped up monitoring. The seal was expensive to fix, so he wanted to wait until the problem worsened to perform a total fix.

The manager placed a bucket under the roots blower’s seal to monitor for complete seal breakage—the failure would be indicated if the bucket filled up quickly rather than a drop at a time.

Monitoring Software with Health IndicatorsFigure 1. The monitoring software shows a photo of the roots blower and motor with health indicators overlaid. Reliability managers can select the health indicators on the image to access a dropdown menu of indicators to show a variety of vibration, temperature, pressure or battery voltage readings. (Graphics courtesy of KCF Technologies)

Before installing wireless sensors and securing the accompanying data analysis, the only other monitoring that supplemented the bucket method was a quarterly or monthly read with a handheld stethoscope. This method gave the reliability manager a limited snapshot of his plant’s operations—like seeing two minutes of a 90-minute movie.

The plant upgraded to wireless sensors in December 2015. During the reliability manager’s vacation, he received immediate notification through email and text messages that the blower was experiencing failure.

He was able to quickly reach the reliability team member he had appointed to check the bucket while he was on vacation. A large amount of grease in the bucket confirmed that the seal had broken.

This quick catch enabled the reliability team to quickly fix the seal on the 150- to 200-horsepower motor driving the roots blower and change the parts to avoid a costly failure and lengthy downtime.

The company invested around $25,000 for a wireless system, which included 28 sensors that were installed on 14 assets. The company estimates that the discovery on the roots blower saved $80,000. The investment paid for itself three times within the first month of the wireless sensor system’s installation.

Using vibration monitoring to detect problems in machines and equipment has been part of the industrial predictive maintenance (PdM) strategy for decades, but it has been limited to two methods: wired systems and high-end stethoscopes.

Wired systems are expensive and complicated to install. With high-end stethoscopes, maintenance teams can take occasional readings, but this monitoring takes place for only a few seconds once every 30 to 90 days. With this method, reliability team members spend 90 percent of their time searching for problems and only 10 percent fixing them—an extremely inefficient approach.

Now, wireless monitoring systems can bridge the gap between wired systems and stethoscopes. Using wireless technology, industrial plants and mills are monitoring more of their equipment on a 24/7 basis. Advancements in wireless monitoring have made observing machine behavior and eliminating downtime easier than ever.

When this chemical company installed wireless sensors to track both vibrations and temperature, its reliability team was able to identify potential failures sooner.

As shown in Figure 2, the sensors’ PdM hardware, software and remote monitoring revealed that the roots blower had reached a warning threshold—an issue that likely would not have been caught by a wired or route-based system. Sentry engineers monitoring the sensors noted the increased levels and immediately alerted the plant’s reliability manager and team. The team then corroborated these results with handheld readings (and with the full bucket of grease) and changed the motor seal on the roots blower before a catastrophic failure occurred.

Monitoring Software for Vibration AnalysisFigure 2. This monitoring software graph shows the indicator level for analysis of the vibration. The top image shows a drastic increase in the vibration trend over the period of a month.

Wireless sensors are just one piece of the PdM puzzle. The secret to an effective PdM strategy is real-time data analysis. Qualified mechanical engineers can conduct comprehensive data interpretation to help chemical companies address why potential failures occur rather than simply addressing the symptoms.

Identifying this roots blower failure allowed the chemical plant to extend the part’s life cycle by 50 to 100 percent. A standard two-year life span for the roots blower may have been extended to three to four years.

Questions to Ask When Installing Wireless Sensors

When considering installing wireless sensors on machinery, make sure to ask potential vendors these questions:

  • What is your installation support process?
  • Do you provide on-site installation?
    • Are the alarm thresholds appropriate?
    • Is ongoing, cloud-based monitoring available to help us catch failures?
  • Who owns the data?
  • For cloud-based data, how long do you store it?
  • How much training is included in your packages?
  • Is the training on-site or virtual?
  • Are in-house, certified vibration analysts available to help with remote monitoring and machine diagnostics?
  • Is the data full-spectrum or trend-line only?
    • What is the frequency of full-spectrum readings?
  • Is the battery proprietary or Duracell?
  • What is the battery life?
  • Is the system a true wireless or an “octopus” system?
  • How large is the footprint of the wireless signal?
  • How will the wireless signal impact my mill’s other wireless signals?
  • Is there a cell modem option, or am I forced to ask my IT department for bandwidth?
  • What is the price (sensors, collection servers, software licensing, troubleshooting, training and ongoing analysis)?