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10 Dec 14: Agitation (and Aluminum) continue...

If you readers want to continue to show the energy to write this newsletter, who am I to stand in your way?




I'm really disappointed that no one has pointed out the superior thermal conductivity of aluminium versus cast iron.  At 125C, cast iron= 50 W/m2M, steel is at 51 W/m2K  and  Alu=215 W/m2K or at least 4 times more efficient.  This could mean lower pressures and thinner walls for the same heat transfer number.




Bryan Creagan

KSH Consulting

Montreal, PQ, Canada


to which I said,


Or, one could use fewer dryers, shorten the machine and building and really save money.


and Bryan responded,


This is true but to a point, I'm not sure what the higher surface temperatures would do to the sheet.  Flashing or case hardening might happen particularly with LW sheets.  A combination of lighter cylinders and fewer dryers would be a nice way to reduce operating energy costs and capital cost for the building. 


I wonder what a 72" diameter 330 face cast thin wall aluminium cylinder would cost compared to a 175 psi cast dryer for linerboard.




Bryan promised to go off and look at prices. We await his results.


Then, this popped in:


Paraphrasing Brian, "high-caliber forward thinking costs time and money".

Really?  I submit it depends on which line of the final project cost summary you are looking at, instead of the bottom one.

Let's say engineering is ten percent (10%) of total project cost.  That's usually a point of discussion in itself, but it's a nice round number so we'll use it here. 

I also submit that whereas it may be true that "high-caliber forward thinking costs time and money", that doesn't necessarily translate to greatly increased total project management/engineering costs. Some, yes, but probably not a lot.  Would you agree on a really high outside number of 5%?


What project have we ever looked back on after completion and said that with better project management and engineering we couldn't have saved at least 10%?  i.e., twice the added engineering?


Point made.


Laurence Coulson

Knoxville, Tennessee


and Bryan responded:


Hi Lauri, it's been a while. 


You're right, the comment was directed to the true front end cost of the +/-20% study where concepts are put forward.  Right now detailed project engineering is around 5-6% of the total capital cost and the +/-20% study is 0.1% or less of the total CAPEX.   This little piece of work is what defines the whole project so if we spent a little more time on it we would for sure save CAPEX in the long run.  The unfortunate thing is that poor planning, compressed study phases and low expenditures for engineering up front, forces everyone into the same old, same old approach.


Innovation and risk taking are just not rewarded in our industry.




Bryan Creagan



But a final comment from me (at least for this week) on aluminum dryers.  Given the weight saving aluminum dryers bring, we can seriously consider cantilevering dryers.  The weight of the supporting structure and bearings on the drive side, while of a different design than today, should weigh no more than all of the backside machinery of today used to support cast iron dryers.  Light weight aluminum dryers with no front frames, no front lube systems and no front bearings would be a dream to keep clean.  We can do this folks.    Jim


Comments? Please send an email to
with "LGMI Frontiers" in the subject line.   

LGMI Design Practices
As always, your comments will be appreciated.
Think light!


Brian Brogdon, Ph.D.
Executive Director




Jim Thompson

Send us your comments by emailing Brian Brogdon
or Jim Thompson!




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