Thermography provides important information on the condition of equipment components and the lubricants used without requiring stoppage or even slowdown of the production process. The role of thermography in component analysis is therefore on the rise. Untrained viewers, however, are at risk of drawing the wrong conclusions from thermographic images. For companies offering such services it is therefore essential to have appropriately skilled staff. A certified thermography specialist can correctly evaluate the material gained in order to show where there is potential for optimisation and propose specific measures.
We have been talking to Kurt Remde, certified thermography specialist at Klüber Lubrication.
What is thermography? How does it work?
Thermography is an imaging process measuring thermal radiation and then indicating the varying surface temperatures through colours in a graphic image. Infrared radiation, which is invisible to the human eye, is converted into electrical signals by means of a thermal imaging camera. The camera then generates an image from the temperature data that tells experts important things about the condition of the object under inspection. This is the valuable contribution thermography can make to machine failure analysis and a better understanding of what's going on in an application.
What benefits does thermography offer that other methods don't?
One benefit is that with thermography we can generate an infrared image while the machine is running, because we do not have to touch it. Any overheating, and its location, can be detected very quickly. For more conventional methods, by contrast, the machine has to be stopped and components may have to be removed to allow analysis of the oil or grease. This inevitably leads to downtime.
Where does Klüber Lubrication use thermography methods, and how do users benefit from these analyses?
Klüber Lubrication focuses on equipment failure analyses, i.e. in this case in rolling bearings, hydraulic systems, gearboxes and open gear drives. With the aid of thermography, the process concerned can be visualised. This gives our customers a better understanding of what's going on in their application, helping them with their decision-making. An image is often more telling than a long written account.
Thermography can, for example, be useful to demonstrate alternative solutions offered as part of our services aimed at increasing performance and energy efficiency. This method enables us to show where there is potential for optimisation at the customer's and make responsive suggestions which lubricants to use. By means of thermography can, for instance, the temperature drop following switchover to a more efficient speciality lubricant be visualised and documented.
What does that mean more specifically, and why is a lower temperature desirable?
High temperature in a component indicates a high degree of friction, and hence high wear as well. Moreover, overheating reduces lubricant life, leading to more frequent maintenance. And last, but not least, higher temperature always coincides with higher energy consumption. A temperature reduction in lubricants, as can be achieved by a switchover from mineral oils to synthetic oils, is therefore desirable. It enables longer lubricant life and helps significantly reduce component wear and energy consumption.
Can you give us examples from practice where thermography helped increase the efficiency of machines?
We measured the temperatures at two large conches in the plant of a well-known sweets manufacturers with activities worldwide. In this plant, two identical gearboxes were operated with two different speciality lubricants made by Klüber Lubrication: one was running with an NSF H1 PAO lubricant, the other with a Klübersynth UH1 6 oil of the same viscosity. Thermography showed a temperature difference of 30 kelvin. For the customer, this means that the use of polyglycol oil from Klüber Lubrication can lead to a temperature that is approx. 30 degrees lower than with a PAO. This reduces the thermal load acting on all components of the machine. The oil can be used longer, service life is extended.
What needs to be observed when performing thermography measurements?
Thermography analyses should only be performed by certified and experienced specialists using appropriate, professional equipment. This ensures correct measures and a meaningful interpretation of results. If not backed by sufficient training, the results gained are liable to highly misleading interpretation.
What is the target group of your services?
Basically, our services are of interest for anybody dealing with the issue of energy efficiency. Some companies have specifically assigned energy experts to this task. In other companies, this subject lies within the responsibility of production, plant or maintenance managers.