At a refrigerated food storage warehouse in California, employees were unaware that a critically-loaded disconnect switch had overheated. If it had not identified by infrared scan and repaired, the mechanism would have failed. Nearly $5 million worth of food might have been spoiled.

At a Miller Brewery, also in California, infrared detected a bad starter on a pump motor in the mixing room. Unchecked, its failure could have spoiled an entire brew-- 33,000 gallons--and affected production for months. There would have been no product available for packaging.

At a starch and gelatin manufacturing facility in the mid-West, the timely repair of hot spots found as part of a twice-annual infrared inspection saved nearly $800,000 in lost production and wages of idled employees by unplanned shutdowns.

Those are three examples of how infrared imaging is helping food processors maximize profits and productivity. Because food processing and storage operations run continuously--24 hours a day, 7 days a week--the failure of a electrical or other component can cause an unplanned shutdown or a shift in temperature that simply cannot be tolerated.
 

The equipment in a food plant that infrared is able to monitor is not limited to electrical apparatus. At the Miller Brewery, for example, since temperature control is a vital element of the brewing process, the motors in the nine 700-horsepower ammonia compressors, and associated equipment used to cool down entire building interiors to 34 degrees F during aging are high on the list for infrared inspection. Also, they use infrared inspection on the roof and doorway insulation that surround the buildings. In southern California temperature average 70 to 105 degrees F.

Miller uses its infrared camera to spot hot spots on the surface of the boiler that provides process steam. They can determine if the refractory lining is worn. When worn spots are found, even though they may present no immediate problem, they are monitored to trend their condition until repairs can be made.

Miller uses infrared to check the many pumps and valves that are critical to the brewing process. In one instance, Miller found a hot spot on one of the malt mills that showed up when it was returned to service after an overhaul. The hot spot proved to be on a special bearing that was corrected without disruption of production.

Before the product gets to the packaging area, it travels through miles of piping as it it transformed from wort to beer, at temperatures ranging from 170 down to 34 degrees F--each critical to its final quality. With infrared, Miller can scan every inch of the line if they wish, or simply certain areas if they suspect a problem.

On the brewery's seven packaging lines the cans and bottles travel over conveyors as they are received at the loading dock, cleaned, filled with product, pasteurized--or heated and filtered in the case of draft beer--sealed or capped, cartoned, placed on skids, and returned to the loading dock for shipment.

With seven lines, Miller has a little more breathing room than it does in processing, but not much. The threat to product quality of a problem on even a three-foot section of conveyor is just as great. Additionally, there are hundreds of pump motors, valves and switches that operate the brewery's filling, pasteurization, warming, closure, labeling, cartoning and palletizing stations that must be monitored to ensure quality.

So each is subject to infrared inspection, as are the jetters in the bottle filling area that shoot hot water into the bottles as they pass by at the rate of 1,100 per minute. The jetter water must be 180 degrees F for it to perform its job effectively of foaming the beer and forcing air out of the bottles. With infrared, Miller monitors the jetter heater, the heat exchanger used to prepare the water, its electrical system, and its valves for clogging.

An image is usually worth a thousand words or curves on an oscilloscope screen.

Miller monitors the equipment that maintains the temperature-critical environment in the pasteurization area. In the case of draft beers, it monitors the warming room and filtering systems that replace pasteurization. Finally,it monitors there are the motors that operate bottle labelers, the cartoons, and the palletizers.

All hot spots that infrared monitoring detects are repaired on the spot whenever possible--as a loose electrical connection that can be deenergized with minimal effort or complication. If not, it is recorded on the camera's built-in disk. The thermographic and real images accompany a work order which is issued for the part's repair or replacement.

The seriousness of the hot spot, and the urgency of repairs is determined using a prioritization that accounts for such factors as safety, importance of the part or component to production, and the availability of a back-up part or component.

The thermographic image has a true advantage over some of the other inspection techniques Miller uses, such as laser alignment and vibration analysis. It is useful to Miller operating personnel unfamiliar with these technologies, but who often must okay the decision to shut down for a repair that can't wait for planned corrective maintenance. An image is usually worth a thousand words or a curve on an oscilloscope screen. According to Miller, they have only scratched the surface with infrared, and are discovering new ways to use it every day.

They found a hot spot on the elbow of a pipeline feeding grain from a silo to a malting room, indicating probable wear due to friction. Now they intend to add this and similar pipelines to the infrared inspection route

Miller believes it can use infrared to spot potential problems on the crowner elements in the plungers on the bottling lines. There, even a 2 or 3 degree temperature rise indicates friction wear that results in improper torque and an unacceptable cap crimp.

At the starch and gelatin plant, prior to infrared they were doing a bit of preventive maintenance--visual and touch and feel inspection. However, this was after-the-fact maintenance. After attending a seminar on steam traps and being sensitized to their importance of maintaining them properly, they asked a consultant who was performing an annual infrared survey in the plant to take a look at a few of the nearly 500 steam traps they had. They were so impressed at what he found, the efficiency with which he found it, and the energy savings that they bought their own infrared camera system.

The camera paid dividends for the food processor. It not simply detected faulty steam traps--that ironically, are being phased out of the plant's production process as equipment is switched to gas--but also detects hot spots in electrical apparatus and other critical components of the plant's continuous processing system.

For example, it detected a single phasing motor on a separator pump at the end of the milling section. Electricians had changed the motor but the pump continued to run at half speed--taking down one of the milling departments. Thanks to infrared technology, they were able to determine that the problem was a bad contact invisible to the naked eye.

In the other milling department, infrared showed a cold phase that led identified a broken wire connection that also was causing single phasing--a primary feed pump motor.

A scan of one of the plant's 17 substation breaker cubicles revealed a solder wire connection to a bus bar had melted causing a short. An unplanned outage would shut down one grind building and the administrative building housing the engineering, shipping, and receiving departments.

Were it not for infrared, the maintenance group would have fixed or replaced the steam trap and still not licked the problem. Infrared turned a probably fruitless exercise into a successful 30 minute repair.

At one of the food processor's other facilities, infrared found four failing electrical disconnects on two of four flash dryers. Undetected, they would have failed and taken down the dryer at a cost of $2,663 an hour, not including replacement or repair costs of components.

At yet another plant, where management had recently replaced their transformers, the infrared unit detected a bad connection to a main in-feed transformer, that could have shut down that facility for a day, at a minimum cost of $20,000. Instead, the installation contractor made a temporary repair then fixed it permanently at the next planned shutdown, all under warranty.

On one recent infrared inspection of an overseas plant, the infrared found a hot ground in one of the plant's electrical motor control center buss bars and potentially dangerous loading on several lighting panel circuits.

Despite the list of accomplishments, like Miller, the starch manufacturer sees greater potential for infrared ahead, as the severity of the hot spots they find decreases. If that trend continues they expect to start finding fewer hot spots, allowing them to reduce the frequency with which they scan some components. When that happens, there are dozens of other things they intend to look at with infrared such as:
 

•  tank levels to confirm gauge readings and recalibrate if necessary,
•  refractory lining in their gas dryers, and
•  temperature loss around steam lines to determine if insulation repair or retrofit is cost justified.

Also, they have some small Dorr Clone units that separate the starch by swirling it around in hundreds of tubes. Infrared should be able to spot clogging in those tubes too small to show up on pressure gauges but significant enough to reduce output and affect product quality and make treatments more difficult.

Finally, they would like to scan the fans in the dryer section, applying the engineering principle that says if you have anything less than a 25 degree temperature difference between the inlet and the outlet you have a leak.