Infrared Technology is one of the most important tools that can be used in a successful PDM program. This technology is not just for finding abnormalities with electrical components and equipment that is "hot" - it can also find potential problems that are not "hot".

The capabilities of an Infrared imager are limited to the imagination of the Thermographer. There are many potential problems that can be identified with IR that some may not be aware.

Locating material build-up in baghouse hoppers, coke gas lines and flue gas ducts are a few instances where you are not looking for the hottest temperature, but instead, the coolest. As long as there is a differential in temperature between the build-up of material and the gas passing through the equipment, you will be able to visually see the material through the lens of the IR camera. If the differential in temperature is small, avoid sunny days when the selected equipment is located outdoors to avoid errors from reflections and solar gain.

The example above is a baghouse in a Steel Mill. It is collecting the emissions from a Ladle Refining Unit. There is a 20 Deg. F. differential temperature between (Sp1) purple, (the material build-up) and (Sp2) white, (the gas stream.) The solid materials presence is quite noticeable.

This example represents a large diameter duct elbow transferring gas and metal particulates from an EAF Furnace to a Baghouse. There is a 30 Deg. F. differential temperature between (Sp1) purple, (the material build-up) and (Sp2) white, (the gas stream).  There is considerable accumulation in the duct.   

The two examples clearly show that solid material is present in both. This not only restricts the air flow through the equipment and can affect production, it also adds considerable weight to the structure that it may not be designed to withstand.

Click here to view a more comprehensive tutorial on using IR to detect build-up.

Tip provided by: Chuck Landsettle
Timken Reliability Solutions