Your flexible friend in the food factory

28 August 2017

Suzanne Gill finds out where thermal imaging technology can help around the factory.

To achieve the goal of faster, better and more efficient food production at ever lower costs requires engineers to maximise plant uptime. To do this requires the ability to predict when components or electrical connections are verging on failure.

Thermal imaging has an important role to play in any predictive maintenance programme. Essentially, it can make the invisible, visible to provide clear evidence of a fault via an abnormal heat signature. It can be applied to many applications – from high voltage equipment, low voltage cabinets, motors, pumps and heating elements to monitoring systems for energy loss or missing insulation

But why choose a thermal imager as a temperature monitoring solution over other options? Anders Andreasson, director global business development - Automation & Industrial Safety at FLIR said: “Thermal images can measure temperature without contact so the technology offers a quick and easy to use solution.”

 Andreasson goes on to explain that, while this is also true for other solutions, such as spot pyrometers, for example, he argues that thermal images can offer more. “We also offer an image so you know where you are measuring. This makes it easier to align the sensor and to evaluate exactly where the measurement is being taken. Another benefit is that we can measure on an area, not only on a spot. Thanks to built-in analysis we can then find the warmest, coldest or average temperature of an area. The sensor can then transfer only the measurement or alarm signal over standard industrial protocols like ModbusTCP or Ethernet/IP. This saves bandwidth and simplifies installation.”

Thermal imaging is widely used within the food industry. For example, to monitor conveyor ovens, where it can even form part of a feedback loop to help control temperature. It can monitor temperature uniformity across the width of the cooking belt and can raise the alarm if the heating element inside an electric oven fails, or there is uneven heating across an air impingement oven.

Thermal imagers can also help ensure packaging integrity. For example, a thermal imaging camera employed to inspect heat-sealed cellophane covers over microwaveable meals would be able to see heat radiating from the lip of the container where the heat seal is formed. The temperature along the perimeter of the pack can be checked by the thermal imaging camera partnered with machine vision software.

This type of programme matches the geometric pattern of the image and its temperatures against a comparative, computer stored template. An added function in such a system could be laser marking of a poorly sealed package so it can be removed at the inspection station.

An issue that indirectly affects product safety is the integrity of cartons that overwrap and protect food containers. One of the most popular ways of sealing the pack is to use heated glue spots on the carton flaps. Checking the efficiency of this process is another task to which thermal imaging technology can turn its hand. 

Cold and hot
While higher-than-normal temperatures are common indicators of impending problems in electrical connections and components such as bearings, lower-than-normal temperatures can also demonstrate a problem.  

Infrared cameras can be used to visualise sub-zero temperature patterns so are equally suited to ensuring industrial freezers are working optimally. In a single pass, the camera can provide a thermal image showing any failure in insulation that might compromise performance or lead to downtime.

Averting fire
A small electro-mechanical fault can have far-reaching consequences and the effects of a fire are often underestimated. Indeed, around 35% of all industrial fires are caused by electrical faults. With thermal imaging included in the preventative maintenance regime, the majority of problems that could cause an outbreak of fire can be detected before they have an opportunity to damage the efficient running of an operation.

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