"More on the simple goal" Note: Emails are organized in the order received, with first received at the top. Jim, Perhaps one step toward making the paper machine lighter is to focus on making the dryer much smaller. It occupies the major amount of real estate and requires a major amount of iron, and concrete, and building superstructure. Diluting fiber suspensions to 0.2-0.5% consistencies, dewatering, then drying the web, is a very large unit operation that takes a lot of energy and hurts the carbon footprint. Just think of the major savings that would reward a design breakthrough. It is interesting to note the overall length of a tissue machine compared to a linerboard machine and the high speeds that are readily attainable with a simple machine configuration. With the advent of fabricated light weight steel Yankee dryers, the cast iron Yankee may become a thing of the past. Thought provoking! Don D. Toronto, Ontario Canada *** Jim, I have already reduced the weight of a paper machine by more than 50%. Please go to my web site (http://casacoco-llc.com/casacoco11.aspx). And you will find a side elevation of the PM or take a look at the attachments. I also attach some files for your info. I have offered it to IP, Metso and Andritz, but they do not get it! With my concept you can make paper by programming your paper machine to do what you want it to do. Kind regards, Cato Sandberg Sommers, Connecticut USA *** Hi Jim Excellent idea on the weight reduction. Especially in connection with your previous one on nomad paper-mills. Dave Bennett's suggestion on aluminum alloy for dryer cylinders reminded me of a suggestion from a metallurgist in the seventies that titanium would fit the bill even better, for the same reasons as aluminum but very much more so; due to better strength weight ratio and conductivity of the alloys and corrosion free. Of course, at the time titanium was a real exotic metal and the capital costs stopped it at the first calculation run-through. However, even then ROI did not seem that bad. So if anyone does the aluminum calculation just run it with titanium as well. Best regards Chris Bennett Peterborough United Kingdom *** Except that once more you've discriminated against those of us from the old empire given that we spell those things -correctly of course- "pyjamas" [And so could never understand the second part of the riddle!] I'm not too serious. All the best. John Reid Kinleith New Zealand *** Jim, My 1st paper project after leaving the steel business in 1984 was a big coated food board machine. Unlike tissue and towel machines with a Yankee or two and a few dryer cans, this one had ~100 dryer cans. If these puppies could be lightened, well ... a lot of energy could be saved. Another thing, besides the reduced electrification costs, being a control systems guy, I can tell you that you'd inherently have better speed regulation and thus better quality control and fewer sheet breaks. And it goes on ad infinitum. Larry Wells Atlanta, Georgia USA *** Jim, I enjoyed reading your articles on a simple goal. We are considering replacing some of our old dryer cans so I sent Dave Bennett's response to three papermachine vendors and I have not gotten one positive responses yet. The responses have been more along the line of "Why would you question cast iron, its worked so well for so long" The salesmen have copied the engineers on the responses so it will be interesting to see what, if any, further responses come through. It never hurts to get people thinking from time to time. Gerry Craig Carthage, New York USA --- Gerry, It is just like I demonstrate in this week's column with the turbine race car and the new yacht design. Someone will come along and blow these suppliers out of the water someday and they will be standing around saying, "what happened?" Jim *** Good Evening Jim, I thought very hard about your "be safe" admonition during my week at camp, and managed not to cut my fingers on the table saw, get mangled in the river, fall into poison [anything - I'm allergic to all that stuff], or be punctured by misdirected shots from the rifle range [not completely sure I was not shot at]. Then I came home and promptly had my daughter dragged off to the hospital...nothing too serious beyond being with her in the house of pain over night after she took a trip in the meat wagon...it never ends. Looked at your essay of the week, and have a few thoughts for you: 1. I am not completely sure what is driving your suggestion for redesign of machine components, though I really like the idea of parts doing double duty. If the objective is to reduce capital cost, I am not sure what component redesign is going to do. My sense [not backed up by data] is that the capital cost is only a small part of the life cycle cost of the machine. I believe that energy and fiber costs dominate the LC cost, and even labor costs are not that significant, really [though labor costs are most easily controlled by the mill]. I would like to prove that theory someday. 2. I agree that there is an opportunity to optimize component design, though I suspect that significant material changes are generally unlikely. The materials used for machinery, in general, is inexpensive, strong, easily fabricated and machined, and maintainable in a mill environment without exotic tools and personnel training. Component sizing is driven by mass [for vibration control], factor of safety and deflection. Greater use of advanced engineering tools, such as those used in aircraft design, could help to reduce rotating mass and thus reduce energy consumption to a small degree. A better understanding of required factor of safety [5 is the number generally used - because it works empirically] and optimization of component design to minimize deflection will require significant research. 3. You have written in the past about "right sizing" paper machinery. I think that there are too many huge specialized paper machines, not necessarily well sited with respect to the points of raw material supply and customer points of use/consumption. These machines typically do not have the flexibility to manufacture a range of products. Could development of machinery better able to meet local needs, utilizing appropriate automation to optimize labor costs, and able to make a wider range of products be a better goal? 4. Addressing operating cost issues, I think an important improvement would be to increase the amount of mechanical drying. This is vital to reducing drying energy costs by reducing the use of natural gas or steam. This would seem to be a technology area that deserves more research attention. I do not have enough knowledge to know what the practical limits of mechanical drying are, though. 5. One simple thing mills can do to reduce energy cost is to stop overdrying. Normally, as you know, this is done to get an even moisture profile. It would seem that the right thing to do is fix the moisture problem [which is tough, but if it were an easy job they would have asked somebody else]. This would have a side benefit of reducing fiber costs. An old saw, I know, but I still see this happening in essentially every mill I go into. 6. Again, being more focused on machinery, I don't know what can be done to reduce fiber costs. I hear all kinds of stuff about fiber, from eucalyptus to recycled fiber to hardwood, and know just enough to be dangerous. Could more blending of fibers and engineering of paper machine furnish, like is done for concrete or steel, help to optimize fiber cost? John Laswell Appleton, Wisconsin USA ### Have a comment? Send your email to jthompson@taii.com. Unless you tell us otherwise, we will assume we can use your name if we publish your letter.