8 Jun 16: Should we be thinking about weight in terms of production-part 2
Faithful contributor Brian Creagan responded to last week's column with this:
"Jim as you said, 'assuming Fourdrinier technology' and assuming that dryer section length is proportional to output speed, the rest of the machine is not proportional to output for a couple of reasons. The first is cantilevering requirements imposed on the Fourdrinier by added components for dewatering. The proportional increase in mass for the cantilever beams is far less than the increase in output capacity. The same applies to press sections. Now if both sections used seamed wires, then the increase in mass would be close to proportional but the initial weights would be far lower to start with. Same thing for the press section. The reason weight increase is the higher mass of the rotating components due to critical speeds.
"It's a simple calculation to check this out."
Well, Brian, I would agree with you, but for the following. I have seen with my own two eyes a new machine that uses seamless wires and felts and is not cantilevered! It uses a special set of shoes built into the columns on the tending side. Powered by water pressure to lift the machine, it has small belts in these shoes that "suck" the wire or felt (depending on location) into the machine much like a dollar bill changer works. So, there is no proportional weight savings or gain based on unit operations design in either the forming section or press section.
with "LGMI Frontiers" in the subject line.
As always, your comments will be appreciated.
Brian Brogdon, Ph.D.
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