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Buildup on duct walls

by khalednasr
Tags: buildup, duct, walls
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Jan17-14, 05:42 AM
P: 2
during a manufacturing process, hot air flows through a duct carrying fine particles of a glutinous substance. With time, those particles stick to the walls of the duct and create a thick layer on them. This layer reduces the cross-section area of the duct, changing the velocity of the flow. To remove this layer, the flow has to be stopped.

Any ideas of how to remove the layer without having to stop the flow? Or to prevent the buildup of the layer?

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Jan18-14, 06:06 PM
Sci Advisor
P: 1,910
If the material is knocked off the walls while the system is operating, can the debris be allowed to flow on through the system or is it then a contaminant ?

Is this a building material or a foodstuff with safety related implications ?

Possible solutions are;

1. Introduce a laminar flow clean air layer onto the wall that would keep the main flow away from contact. That would significantly reduce build-up.

2. Use mechanical blades or air knives that cyclically move along the internal walls to shave the build-up.

3. Attach vibrators to the outside of the duct to shake off any build-up.

4. Use a loop curtain like a conveyor belt. It could have a roller at each end with a fixed insulated wall inside. Powering the roller would move material around the roller where it might be knocked, peeled or cut off. Once the inner surface was outside it could be washed without any need for a shut-down.
Jan19-14, 03:11 AM
P: 2
Great answer, thank you very much!

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