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The Light Green Machine Institute
Weekly
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Check out Nip Impressions weekly
|  | Nip Impressions® is Paperitalo Publications' flagship publication. Published every Thursday afternoon (US Eastern Time), Nip Impressions® is eagerly read by pulp and paper professionals around the world and is ranked the No. 1 website in the industry by Alexa.
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27 March 2013:
Faster versus wider
|  As we have stated previously, we are going to be taking the ideas developed in this column over the last couple of years and developing them into design practices. This is how it works. We will provide the basic narrative here for one design practice each week. We will keep it open for comments for one month. After that, we will finish it in formal form and offer it for sale at a modest price. Here is where you come in. If you make a substantive contribution to a standard, the organization for which you work will be granted a pro bono license to use that standard with its current issue number for as long as you like. We have had good response so far! Contribute, please
This week's:
Faster versus wider (LGM 2013.012.01
when issued)
Reference:
Conventional paper machines were built as wide as possible with the objective to increase production output. The width of a paper machine is a dynamic issue, and what one is really interested in is optimizing the total area of paper or paperboard produced within a given period of time.
Objective:
To optimize the width and speed of the paper machine.
Consideration:
The question is, "What is the optimum narrowest width to produce the maximum amount of product?" Beyond a certain width, the size of motors, bearings framework and so forth becomes uneconomically large. Building a narrower paper machine has certain advantages, namely: It requires less horsepower and is easier to balance at higher speeds.
However, all must be considered when sizing the machine width. The product output capacity of a paper machine is relative to its size. The larger, that is wider the machine, the greater the amount of product. Therefore, in the past paper machines were designed as wide as possible. At higher speeds, wider machines require a bulkier framework, the motor sizes are larger and an increase in the number of mechanical components including bearings, often lead to increased downtime, maintenance and vibration problems. Alternatively, operating the paper machine at a faster speed will increase the rate of production, but may also result in an increase in the number of web breaks, thereby reducing the output capacity. Ultimately, the optimum performance of a paper machine depends strongly on Speed Efficiency.
Still open for comments: Planetary Gearboxes (Open until 2 April 13) |
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As always, your comments will be appreciated.
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Think light!
Brian Brogdon, Ph.D.
Executive Director
or
Jim Thompson
Founder
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LGMI Feedback
Jim,
A prime example of transition to steel from cast iron exists in the tissue industry. Over 150 examples are in operation today in the form of Yankee dryers with diameters ranging from 10 to 22 ft and pressures up to 150 psi. Today, for a new tissue machine, the question "is why should I buy a cast Yankee?" not the other way around. Steel Yankees are cheaper, more efficient and safer than cast cylinders. As usual, the tissue industry leads in innovation while the rest of the industry lags behind.
Regards,
Bryan Creagan
Send us your comments!
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Disclaimer
LGMI Weekly Ideas are presented for your consideration and inspiration only. It is solely your responsibility to check for engineering correctness, applicability, standards, insurance policy and local, national or any other legal compliance required before implementing. Neither The Light Green Machine (TM) Institute, Paperitalo Publications, Talo Analytic International, Inc., nor any individual associated with these entities accepts any responsibility for your application or compliance issues.
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