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Participant

Join Date: Aug 2012
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Thickness of Roll from Drying Can

08/23/2012 7:25 PM

How can I control the thickness of paper roll ( recycled paper for toilet tissue) coming out of the drying can? The inputs are pulp (from recycled paper) and dispersant. I was thinking of controlling through a conductivity meter measuring the pulp. Will this work? I also don't know the correct formula for mixing dispersant. The writings on the bags are in Chinese, and nobody can read them here.

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#1

Re: Thickness of Roll from Drying Can

08/23/2012 8:02 PM

<sigh>

First it would be a good idea to get instructions you can read for the dispersant from the supplier otherwise your trial and error approach is unlikely to produce an acceptable product.

Second, without detailed knowledge of the equipment you are using to make your recycled toilet paper product we can only offer vague production suggestions, most of which will be unsuitable for your particular situation.

Please consider hiring someone experienced to assist you in this manufacturing setup.

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#2

Re: Thickness of Roll from Drying Can

08/23/2012 8:04 PM

Sensing the conductivity of the pulp could trigger some chemical injection with a metering pump.

Take a picture of the "writings on the bags" and have it translated.

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#3
In reply to #2

Re: Thickness of Roll from Drying Can

08/23/2012 8:32 PM

what instruments are actually used to control paper thickness? The hired expert here is doing a lot of trial and error. what we do is manually throttle the pulp valve, and it is working. Based on that, I want an instrument that will control that pulp valve. But my problem is I don't know what actually needs to be measured for this control. Whether its the pulp concentration or the pulp flow? Are there instruments available for these two?

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#4
In reply to #3

Re: Thickness of Roll from Drying Can

08/23/2012 8:40 PM

Sorry, I have a literal mind.

I would control the thickness of paper with a nip roll.

If you mean viscosity, that's different.

If you mean thixotropy, that's different, too.

There are instruments, in any case.

What are you trying to do?

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#5
In reply to #4

Re: Thickness of Roll from Drying Can

08/23/2012 8:51 PM

what will be the best in my case?

something to do with pulp property.

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#6
In reply to #5

Re: Thickness of Roll from Drying Can

08/23/2012 8:58 PM

"The best in your case" would be to hire someone who knows the process and instrumentation needed for paper processing.

Not here!

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#7
In reply to #6

Re: Thickness of Roll from Drying Can

08/24/2012 12:51 AM

Lyn:

Please play nice.

Apisai;

Not much description of the process. Perhaps you could have your hired expert describe the types of measurements and controls you need and then ask the instrumentation group?

It sounds like a pretty specialized application.

Paper is big business - they have trade magazines I'm sure. Ask your hired expert how many he subscribes to.

Have him bring some of his copies to you and check out all of the advertisers when you have time.

Poop paper sounds like a pretty competitive business - hopefully you've done a good job cleaning up your business plan. Big corporations get sloppy sometimes, especially when there isn't any competition; but I would think they would be on the throne with that kind of process technologies. Unless you've got a really remote market and are close too it; the big guys may hold the door closed on you. I'd hate to imagine what would happen then.

Gav

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#8
In reply to #7

Re: Thickness of Roll from Drying Can

08/24/2012 8:57 AM

That is my nice.

We are obviously dealing with someone who knows nothing about chemical processes nor their sensing or control.

My advice to hire a engineer to set up the process seems the only course here, unless you want to hold the OP by the hand until he has attained the chemical, instrumentation and process knowledge necessary to do his job.

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#9
In reply to #8

Re: Thickness of Roll from Drying Can

08/24/2012 1:44 PM

What strikes me is "The hired expert here is doing a lot of trial and error." This is acceptable to you? Why? Brother-in-law? You obviously have a belief that he is incapable of providing the service for which he collects a fee.

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#10
In reply to #9

Re: Thickness of Roll from Drying Can

08/24/2012 2:19 PM

Ooops! I see I responded to lyn. My comments and questions were intended to be for our original poster, Apisai.

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#11
In reply to #10

Re: Thickness of Roll from Drying Can

08/24/2012 2:37 PM

This sounds more like a viscosity/thixotropy problem than a chemistry feed control problem.

Maybe it's time for a NEW "hired expert".

I can't quite see what the problem is from here. And of course, we don't know where, "there" is, nor what OP really wants to control.

Maybe an in-line viscometer to control the valve?? Probably not. Maybe it is a chemical dosing exercise, but who knows?

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#12

Re: Thickness of Roll from Drying Can

08/25/2012 5:16 AM

Control Thickness? Blade on the rolls ? (two short planks?)

jt.

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#13

Re: Thickness of Roll from Drying Can

08/25/2012 9:54 AM

"Something to do with the pulp" might be bulk, which is desireable in absorbant papers; don't kill this. Tension ("draw") also plays a role, but can just as easily lead to lost production if not controlled instantly and properly. You need someone who knows the industry and has done this before. Don't do this by trial and error.

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#14

Re: Thickness of Roll from Drying Can

08/27/2012 8:58 AM

Paper thickness can be measured, but the pulp density which is what you deposit you need to measure inferentially, I would suggest you hire a company specializing in pulp and paper industry technology.

The advice given here is good, but may not apply to your case directly, since you have additional components as dispersants that will affect the deposition rate, thickness, effective drying of the paper, etc.

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#15

Re: Thickness of Roll from Drying Can

08/27/2012 11:15 AM

On a tissue machine the paper usually comes off a large drying can called a Yankee dryer. There is usually a doctor blade that helps scrape it off and helps crepe the tissue. The primary thickness control comes well before this drying step, in the formation of the sheet in the head box and forming section including the Fourdrinier and press sections.

After the Yankee Dryer there is often a Calender section that can help "iron out" some of the bumps and compresses the sheet. This can be anything from two rolls nipped together to a stack of rolls the paper runs through. In general, tissue uses just the two rolls. The paper coming out of the dryer section is usually less than 2% moisture and feels bone dry (just like the paper in the roll you use). Thickness on the dry product can be measured with laser micrometers, but is often measured with fancy equipment in a "O" frame that scans many properties of the paper including moisture content and thickness. It uses a radio active source and requires licenses to operate.

There are many courses available for learning paper making.

Go to the trade shows for paper makers. There is much equipment and many vendors there

WWW.tappi.org is the world standard on paper making. Feel free to search their data. When new or modified machines are designed the "Tappi Standards" are used for sanity checking the design.

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Users who posted comments:

Apisai (2); Doorman (2); Gavilan (1); GW (1); jack of all trades (1); jt (1); lyn (5); Mag (1); vargaalex (1)

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