Opportunities in Wet-End Chemistry: Feature Essay, Posted Nov. 2003

"Troubleshooting"

Martin A. Hubbe
Dept. Wood & Paper Sci., N.C. State Univ., Box 8005, Raleigh, NC 27695-8005
Citation (public domain): http://www4.ncsu.edu/~hubbe/new

Polite people would not be calling at three in the morning. Tell me that it is a dream. Tell me, please, that you're sorry; you got the wrong number. It's a dream, right?

Paper machines are not polite. And Murphy had it right; often things go wrong when its… my bedtime, for instance.

A voice coming through the little openings in the phone handset says something about opacity. Or was it something about winding? Come on, now, this must be a dream. How could someone at the mill think that opacity and winding issues deserve to be included in the same sentence? And if you have to wake me up, please give me just one thing to worry about, not two. Drainage, you say? Three problems?

Coffee, that's the answer. Hmmm. That's better.

"Trouble doesn't just happen." Will Rogers said that, right? Or was it Abraham Lincoln? Anyway, it sounds good. Trouble doesn't know it's my bedtime. It just seems that way. I hope that the tour foreman has a clue about what's going on.

Gosh, it's damp! Maybe it's damp all the time like this at this hour. Maybe I just didn't notice. I wonder if the opacity has been getting low for a while and nobody noticed. Then this shift comes back from their long weekend and Wham! The problem is staring them in the face. Hmmm, I wonder if I could observe things better, too, if I were coming back from a vacation? Dream on, self!

"Trouble doesn't just happen…" There must be a second part to that rule. Like when this car fails to start, there has to be a cause. Like the damp. Like damp points. You will start, won't you. (This car is starting to smell not so new anymore, but I'd better keep my thoughts to myself. I do want it to start.) Good. That's better. Turn key. Car starts. Cause and effect.

Winding. Let's see. They said the rolls aren't building evenly. Could be anything. How did we get out of it last time? Let me see. Slowed down. Hmm. Hate to have to be the one to break the news, if that's the news. But at least it's something. Something to look for. I wonder what the profiles look like.

Drainage, eh? Wonder what they're looking at. Dry-line position? I wonder if they're running too wet off of the couch. I know a cure, but I don't want to know about the cure. Slow down. (No, car, I didn't mean you, I meant the paper machine.) Wait. Maybe there's a connection. The winder's saying it wants to slow down. The table's saying it wants to slow down. Gee, I can't wait to have a good look at those moisture profiles.

Horizon's getting light. Morning? No, it's still much too early. Moon? The Mill? Oh, whatever.

Opacity. Hope someone's run an ash tonight. Wet sheet and low opacity. I wonder if the filler is staying in the sheet. Edwards would have checked that right away. She's no dummy. They aren't gonna wake me up so that I can discover a failed calcium carbonate pump. Are they?

Pump. Well, maybe it could be a different pump. Wet sheet. Low opacity. A loss of retention aid would cause a loss of drainage, right? Gosh, I'm sure that they've been measuring retention. Bet it's low. Bet they didn't want to tell me about low retention, waking me up out of bed and all.

But Edwards would check that. She'd send Stuart down to do a drawdown to check the retention aid flow. They'd take a look at the stuff. Maybe they'd even measure the viscosity to check that it was made down right. That it wasn't mostly water. These anionic polyacrylamide systems need to be watched all the time anyway, so let's say that they already know the retention aid itself is not the problem.

Anionic. I wonder if the system is too anionic. That might explain why the retention aid doesn't seem to be working. I mean, it could explain why the retention aid doesn't seem to be producing the drainage benefits we're used to. Too much refining increases the amount of exposed fiber surface right? Makes the system more anionic, right? Or maybe the same could be eplained by a failure of the alum pump? Or a problem at the bleach plant?

Honey, are you all right? Huh? All right? You mean it was a dream? A dream. Yes, a dream. Go back to sleep! Good thing! If this were real and I had made it to the mill, then you can be very sure that there would be another piece of evidence that still wouldn't fit. Murphy was right. Or was it Lincoln? Trouble doesn't just happen. It has a cause. And it takes more than one sleepy person to figure it out.


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