Sensor for Sheet Break on Paper Machine

[BearB]

I have used several types of Sensors to detect Sheet Break on Paper Machines without problems, both reflex and diffuse relective, also thru beam. I am wanting to install a sheet break device near a Coater where coating that gets applied to the paper surface. The Coater currently has a photocell sheet break device, Visolux RLK 6. This is a very old device and from time to time it gets Coating on its lens and it cannot see through it. I was interested in anyone having any feedback for this type of application to sense Sheet Break.

 

[djs]

You might try a low torque limit switch with an arm riding on the paper.

 

[BearB]

The Coater needs a Sheet Break Sensor close so if a break it will open the rolls to prevent wrapping. The paper would be too wet to have any contact, also any contact with the wet coating until it reaches the dryers will show up on the finished product.

 

[analogkid2digitalman]

I would go with a laser in reflective mode with a large standoff distance (from above, if possible).

-AK2DM

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"It's the questions that drive us"
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[hacksaw]

lens purges work if you have clean air, but they require a careful design to avoid drafting in the contaminant (simple air purges usually are not effective).

 

[BearB]

I will look into the laser.
We do not have clean air in this area. Thanks all, this is a great site.

 

[roydm]

What about an ultrasonic level transmitter, this could be as far away as needed to avoid any spray

 

[Skogsgurra]

I have used ultrasonic in that position in a board machine. Problem with ultrasonic are the nuisance trips. I used three sensors across the web and a voting circuit (majority wins) to cut the web. Actually won a nice trip to NYC on that one.

Gunnar Englund

http://www.gke.org

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