The Light Green Machine Institute

Weekly

Quick Links

The Light Green Machine Institute

LGMI Ideas on Nip Impressions

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.

29 Jan 14: Computerization 1--Not reliable

I'll have to be a bit circumspect about this situation to avoid revealing the mill's identity, but I think I can get the point across, even with this limit.

This particular situation arose when a set of valves controlling oil pressure to some vital cylinders on a paper machine inexplicably opened. This allowed an over pressure condition to exist for one second. Yes, one second. The monitoring data shows it very clearly.

The result was five (5) days of downtime plus equipment damage.

Why did this happen? It appears a USD 500 mechanical pressure relief valve could have prevented the entire episode.

I was talking to a mature friend (old man) about this. He asked why the designers had not specified the pressure relief valve. I calmly pointed out that the designers, even if they were in their forties, have never worked on the old mechanical equipment we grew up operating. They have always done it by computer.

So, despite your standby generators, back up algorithms and so forth, sometimes you need protection that just works. A lesson well worth remembering.

Any comments? Let us know by sending an email to jthompson@taii.com with "LGMI Frontiers" in the subject line.

LGMI DESIGN PRACTICES ARE NOW AVAILABLE!

CLICK HERE

As always, your comments will be appreciated.

Think light!

Brian Brogdon, Ph.D.

Executive Director

brian.brogdon@gmail.com

Jim Thompson

Founder

jthompson@taii.com

_____

Send us your comments by emailing Brian Brogdon
or Jim Thompson!

Available for download: 2013 LGMI Conference Presentations.
On Nip Impressions and the Light Green Machine (TM) Institute.

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.