Inspecting Seals with IR Thermography
James Gambrell Predictive Maintenance Technician Hercules Inc. Pinova div.
In today’s industry, practices that were once acceptable are no longer even tolerated. Environmental concerns and EPA mandates are applying more and more pressure on businesses like the chemical industry to improve the manufacturing processes being used, to the point that not only is a slight drip from a pump seal not acceptable, but in 2004 the MACT will be enacted and only 500 – 1,000 parts per million vapor will be allowed and, eventually, no vapor at all.
Thus mechanical seals and packing for pumps that were once acceptable at a cost of $50.00 to $1,500.00 will have to be replaced with seals costing $3,500.00 to $7,000.00. For a plant with at least 100 or more pumps with seals, that’s a cost difference of up to $700,000 a year IF you can get your MTBF on seals to go a year.
Hence the condition monitoring technologies in use today include infrared, vibration analysis, ultrasound, and vapor detecting equipment. My particular expertise is in the thermography and vibration analysis condition monitoring techniques. My company has already started implementation of advanced mechanical sealing, where a great deal of the seals being used are the double mechanical kind with some type of barrier fluid being used between them, i.e. (water, process fluid, or synthetic oil).
Thermograms before and after seal correction and a visible photo, note the dramatic temperature drop.
The infrared technology can be a great tool if used in a route circuit, check your seals for temperature increases and you will be surprised to find out just how many seals either do not have proper flow of barrier fluid or none at all! Not only will you save and/or increase the life of the seal, but the savings in maintenance and seal replacement can be tracked and documented. The possible bonus at the end of the year isn’t bad either.
In closing; check, track, and document your seals with your infrared equipment, if you do not have thermal equipment it’s time to invest; it’ll be worth the cost. For some strange reason, for the officials in charge, a picture is worth a thousand words, and the IR camera is the only device that can provide it.
Any time you use dual seals (two seals) in an application, you should have a fluid circulating between them to prevent the generation of unwanted heat.
Maximum achievable control technology (MACT) standards are technology-based air emission standards authorized by the Clean Air Act of 1990 and monitored by the Environmental Protection Agency (EPA). The nearly 100 MACT standards are found in 40 CFR Part 63. Each standard regulates a specific source category such as dry cleaners, petroleum refineries, or vegetable oil production.
Mean Time Between Failure (MTBF), a measure of reliability. The longer the time span between failures, the more reliable the device.
Editor’s note: James receives an InfraMation Executive Attaché for his article contribution.