Thermal imaging has been around for nearly one hundred years now and the technology has been used in nearly every type of industry. From search and rescue, to electrical diagnostics, medical and wildlife management, thermal imagery can be a valuable tool in problem-solving situations. Just as thermal imaging has found its place in the aforementioned industries, there are also several applications that prove it beneficial to abrasive blasting operations, for both maintenance and safety.
Blast Pattern (Hot Spot) – Most abrasive blast operators and maintenance staff members already utilize some form of checking the blast pattern regularly. However, some methods are more effective and accurate than others. Using a painted plate (or empty drum in the case of many tumble-blast machines) will give you a decent indication of where the abrasive is hitting, but it is subject to some error by way of abrasive ricochet. The more accurate method would be to use a plate in front of the wheel, run the wheels and abrasive for a certain amount of time, then look for the hottest point and the subsequent leading and tailing edges, using thermal imagery. Only then can you be sure where the abrasive is focused and the abrasive is hitting parts where you wish. See the imagery (Image 1) below showing the perfect “oval” pattern of a typical wheel hot spot along with the leading and tailing edges.
Machine Diagnostics – There are areas on a machine that will normally register hot on thermal imagery, such as motors, gear reducers and the blast cabinet exterior walls. The blasting process alone causes heat buildup in these areas. With that being said, there are also areas of the machine that should not heat up during normal operation. Using thermal imagery, one can identify and correct issues with these areas before they become a large problem. For instance, the housing of the reclaim elevator should be fairly cool, save for the boot section where the motor and pulley sits, and warm abrasive is pushed into this section waiting to be picked up by the elevator buckets. Sometimes, the thermal imaging will show higher temperature spots along the sides of the elevator housing, indicating that the elevator belt itself is off-track and rubbing against the sides of the housing (See image 2). This is a non-invasive way to monitor the elevator belt tracking. Left too long, the sides of the housing will begin to wear through.
To be continued in the next
Written by chris prouty, Contributing Editor for MFN and Technical Advisor at Winoa