The Hard Life of an Ash Auger

My stoker has automatic ash removal via an auger and elevator. After burning a lot of coal (around 150 tons), I noticed ash no longer was coming out of the boiler as fast as it was being created, causing some problems. Further investigation revealed significant wear in the flighting of the ash auger (see pic; the one on the right is an original one).

While nowadays it's often reasonable to question the quality of materials, AFAIK that's 400-series tempered stainless. My takeaway from this is that life can be tough for ash augers. Even at lower burn rates, people who use or plan to use standard grain augers, flex augers, etc. for ash removal probably should include periodic inspections for auger wear in their maintenance schedules.

Mike

Are you producing clinkers that are being ground up in the auger? Burning run of the mine or dirty coal that contains alot of bone? Thats alot of wear!

Why is the series 400 tempered stainless all rusty?

Because even stainless stuff can get rust, and I can't vouch for what that auger has been doing for the past 60 years, but it does not appear to have been doing any of the work that has left the other one so shiny.

Scott, I thought you would be coming forward here to blame it on the half-ton of Newport I ran through this unit a couple of years ago.

Mike

NJJoe wrote:Are you producing clinkers that are being ground up in the auger? Burning run of the mine or dirty coal that contains alot of bone? Thats alot of wear!

One of the functions of the auger in this unit is to chew up the clinkers (so they can be handled by the elevator), and the most pronounced wear on the auger is at the point where that occurs. All of the coal run through it has been clean and properly processed. There was a fair amount of bone in the small batch of Newport I mentioned above, but I don't think that was the cause.

Mike

Series 400 is typically cheaper then series 300. Series 400 is usually a little harder, depending on grade, and even magnetic, but its corrosion properties are not as good as 300, and I believe that is because of the lack of nickel. So its not uncommon for 400 series to have surface rust.

I would think that typically un-burnt coal is "softer" and therefore doesn't wear the input auger like the ashing auger would. Because the ash is typically rock or harder then the pieces of un-burnt coal. But that's my opinion.

Mikeeg02 wrote:I would think that typically un-burnt coal is "softer" and therefore doesn't wear the input auger like the ashing auger would. Because the ash is typically rock or harder then the pieces of un-burnt coal. But that's my opinion.

Yes, the last time I checked the input auger it didn't show significant wear.

Mike

Pacowy wrote:
Scott, I thought you would be coming forward here to blame it on the half-ton of Newport I ran through this unit a couple of years ago.

Mike

I try so hard to forget about that crap

I think the ash wears the auger faster because there are more edges to the ash that would cut. Instead of one big edge going thru every half inch, like on a piece of buck, there is thousands of little edges, like polishing compound.

Man, that is one nicely whittled way piece of stainless!

I guess that's what I have to look forward to. It would seem that the thing to do when putting to gether your own ash auger system is use tube and fighting that is easily replaceable and not expensive.

Mike, how many years, or tons did that ash auger run?

-Don

I've put about 150 tons through it. The unit was reconditioned before I got it. At that time, the exposed portion of the ash auger looked reasonable.

Mike

That's not bad realy. At my rate of 6 ton a year, it's 25 years. But, if you have one of those R85's, you might use a bit more than 6 ton a year.

-Don

Are you going to have new flighting put on the auger?

Yes, that currently is the plan. To buy some time the worn areas were partially built back up by my welder. I also have some similar augers in the garage and am expecting to take possession of a parts unit, so I'm not sure how it will end up.

Mike