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I have a Guide roll on a paper machine. The front side that is Bolted solid has very low vibration. The backside that sits on 2 air bellows the vibration goes up and down from .3 to .5 ips. All at 1X. The speed is approx 7 HZ. I don't really see an issue with this. The bellows are small and flimsy. The only thing I can suggest is to try adjusting the air pressure, and wire tension. Otherwise if still a concern pull the roll and do a very precision balance job. Any comments on this.
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I have wondered if the bellows type guide rolls don't get some indication of looseness if the lower pressure bellows does not have enough back pressure on it. If the lower side had no pressure and the roll was not against a solid stop, would the pressurized bellows act as a trampoline? The roll might not be actually loose but not having any support from one side may make it look loose.

Our guide rolls are not the bellows type so I can't be of any help there. We have several different types of guide rolls, one of them has a double ended air cylinder that moves the roll and is actuated by a linkage from a tracking paddle. The wire mesh belt we use gets ragged on the edge sometimes and causes the cylinder to do some crazy jerking back and forth which really causes vibration readings on the guide roll bearing to look strange.
Sounds like normal behaviour. I suspect the "up & down" will be at wire tracking frequency, ie one cycle of edge as it tracks from tender side to drive side and back again. I believe this loads the bearing races in that direction as well as effecting the 1x.

One thing to check - and this depends on the bearings fitted - if there is an outrigger bearing then it could have a problem. But you might have Timken tapered rollers. High 1x on Guide and stretch rolls is normal in my experience. Often relates to poorly adjusted spherical brackets which do need slight clearance to allow bearing housing to move but not too much. rgds.

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