Impeller Corrosion on Asphalt Plant Extraction Fan

[AmbroseCP]

I am continuously experiencing the same damage to my dust closed extraction fan/impeller on asphalt plant, over and over. Currently installing 3rd new dust extraction fan.

1. Outside Diameter of the fan = 810mm (31.889 inches)
2. Motor and belt driven

The vanes are being eroded at the tip, at the side of the back shroud. I have a damper/variable inlet guide in front of the fan. The damage occurs at a very high rate and replacing the impeller after such a short lifespan, is expensive.

I am considering using Belzona 1321 on my replacement fan to prevent the erosion on the replacement fan. However Belzona 1321 is also quite expensive and I need advice on:

1. Is the Belzona 1321 the answer to my problem?
2. Is there a longer term solution to this problem?

P.S. I have set my variable inlet guide set to 25% open. Some images attached might help clarify my questions.

Ambrose

 

[gerhardl]

What kind of corrosion is this? The picture seems to show grooves made by abrasion, caused perhaps by small hard particles? I have no experience from your industry, but to protect from abrasion you have at least two ways to protect your equipment.

1. Use harder surface (your own suggestion)
or
2. Use softer surface, for instance rubber.

For the last suggestion I have had experience with a steel clad booth for sandblasting iron castings, where rubber coating spared the walls from beeing worn steadily down.

 

[AmbroseCP]

The damage is caused by dust particles.

In the manufacture of asphalt, we use aggregates, i.e. quarry dust, stone and bitumen to create asphalt (road tar).

During the manufacturing process, the fan is extracting the hot air and fine residual dust particles are reaching the fan during this extraction. See smokestack in picture.