How to bring thermography in house

Thermal images from Fluke’s Ti30 show internal operating conditions of electrical components and other devices, such as the sludge catcher’s level, at BP’s Jayhawk natural gas plant.

IN ANOTHER case, we wanted to determine which valve in a faulty system needed to be replaced. Conventional troubleshooting was ineffective due to operating constraints, but replacing all of the valves would have cost $15,000. So, we used the thermal imager to locate temperature deviations in the system, found the faulty unit, and replaced just one valve.

The imager also saved a $100,000 project at the plant, which had been at risk due to faulty pump seals after the vendor’s engineers couldn’t solve the problem. Thermal imaging revealed that the seal failure stemmed from overheating caused by insufficient flow and cooling—not from a faulty unit. If the pump seal had simply been replaced and the real problem left uncorrected, the failure would have led to a spill.

Other Applications Find You
In the gas fields, Alltech’s electricians use the Ti30 Imager to monitor mechanical devices. Thermal images can detect alignment problems in rotating equipment, for example, between a motor and a compressor. With a thermal image, they can quickly discover when a bearing is heating up due to misalignment.

They also use thermography to monitor 24 V control circuits. On these low-voltage installations, the imager lets users pinpoint loose connections as potential problems, tighten them, and prevent future failures. Using its Ti30, Alltech found loose 24 V connections that weren’t problems yet because of their wire’s rating. However, they might have caused shutdowns later if those connections had kept vibrating until their screws and wires came out of their sockets.

Thermography, PdM and Teamwork
Because thermal imagers capture otherwise invisible images of infrared (IR) radiation, and show temperature ranges as color or tone variations, observers can easily pick out hot or cold spots that might signal electrical or mechanical changes and/or process flow problems. This is a natural ally for any predictive maintenance (PdM) effort to regularly collect measurements, track indicators to predict needed repairs, and reduce maintenance costs and production losses.

In addition, with basic imaging training and good plant-floor communications, many different facility teams can benefit from thermal imaging. For example, our plant uses extremely cold processes to remove unwanted gases from the natural gas. In one case, a nitrogen pump had a persistently leaky seal that had to be changed out regularly. The electricians took a thermal image of the pump, and an engineer immediately saw there was a restriction preventing the seal from receiving enough cooling airflow, which was causing the seal to overheat and melt. Another problem solved.

"Using thermal imaging, we determined that insufficient airflow and cooling were causing a particular pump seal to fail. Learning this saved a $100,000 project from experiencing ongoing seal failures."

Also, software included with the imager helps us set up inspection routes for regularly scheduled inspections at the plant and in the field, as well as adjust measurement parameters, such as emissivity, RTC, temperature level and gain for particular locations and pieces of equipment. We’ve used the same software to report inspection results. It uploads all the images we’ve taken, and allows us to add side-by-side digital photos, so the technicians can translate the hot spots on thermal images to locations on the digital photos. We add notes and analysis to each image, rate the inspected equipment, and designate which should get attention first. For example, if a wire is rated for a maximum temperature of 150 °F, and our scan shows that wire is fastened to a terminal lug that is more than 200 °F, then we know we’re looking at a meltdown fairly soon.

In general, we use “high,” “medium” and “low” designations for scanned equipment with problems. “Low” means it can be addressed sometime. “Medium” means it needs to be to taken care of relatively quickly. “High” signifies do something right away. Each year, we put together a book of our findings, and the facility keeps uses it to guide PdM activities.

Besides thermal imaging, the Jayhawk plant uses oil sampling analysis and vibration analysis on its compressors, VOC packing leak detection in valves and pumps, hi-pot insulation resistance testing, and regular switchgear cleaning and electrical maintenance. However, the only warning is to watch out for snowballing use of thermography. As this BP facility found out, once thermal imaging comes in house, applications for it appear everywhere, operation costs start to drop, and efficiency improves. So, what’s left for a plant manager to do?

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About the Authors

Barry Ungles is operations manager for Alltech Electrical Service, and Len Sisk is maintenance team leader at BP Jayhawk Gas Plant, Ulysses, Kan.