Can sludge levels in insulated piping be detected.

[Paulx1]

Can sludge levels in insulated piping with aluminum jacketing be successfully determined with IR Thermography? If so is there any tips I can use or is it more straight forward then I thought.

 

[creg41]

I have scanned pipes before insulated and non insulated. You get a more accurate reading without the insulation, with the insulation there are too many varialbles even if you were to get some kind of reading the internal pipe temperature would have to be extremly hot and the insulation could give false readings if there were moisture between the insulation jacket and the pipe. the insulation thickness, moisture content of the insulation, emissivity of the aluminum jacket etc. would all be contributing factors to false readings.

 

[IRJohn]

The insulation is usually not the limiting factor; rather it is the aluminum jacket which results in drastically reduced emissions of energy.

If you suffer chronic sludge build-up in several areas, I strongly suggest you paint the jacket a light color. You should then be able to have a chance at finding the sludge levels. Sometimes they can be enhanced by briefly heating or chilling the surface of the pipe and waiting for the thermal signature to bloom. Much, of course, depends on the temperature difference and insulation levels.

If you'd like to talk further, drop me a note.

Thermally yours,
John Snell
jsnell@snellinfrared.com

http://www.snellinfrared.com

http://www.thermal-solutions.org

 

[keymal]

i do have the same problem as Paulx1. we intended to detect the sludge/sand level in pressure vessel. Core material is SA 516 Gr 70, insulation mat is fibreglass and jacket made of ss 316. tried it once, but image came out black!

vessels are in shaded area, therefore presumably no sun-loading mechanism which is vital to inspect the vessel during the transition period. Temperature inside is only at 50 degrees celsius.

Looking at the thermal conductivity of common fibreglass (~ 1-2 W/mK), which is very low, is it really possible to detect any difference in thermal radiation on the surface (assuming that the only heat source is from the liquid inside)?

John: what do you mean by painting with light color? is there any reason for that other than enhancing the jacket's emissivity value?

 

[eyec]

emissivity tip/trick

place a strip of black electricians tape on the area you are measuring and take your reading from that. the emissivity should be close to .98 and you will not have to worry about false or misleading readings. just make sure the tape is in place long enought to stabilize the temp.

this also takes care of reflectivity problems.

as pointed out above there are other factors to take into consideration when you are shooting anything insulated; recommend removing section of insulation in area you suspect.