Does anyone have any experince with selecting/installing/using accelerometers for use inside of a suction roll (paper mill application)?

These rolls have an internal bearing which is difficult to effectively monitor externally. I want to monitor this bearing and would like to install a sensor inside the roll.

The operating speed is ~120 RPM (2Hz), high moisture/flooded application with about 20" vacuum.

Any input would be appreciated!

Den

We have since 15+ years delivered our velocity probe VT16.13 for that use as it is sealed with cable out. We also supply a accelerometer as OEM for a manufacturer that upgrades papermachines. Installation I have seen are axial as close as the inner bearing as possible as there is no space for any other mounting.
It is a major improvement compared to taking readings on the bearing house! www.vtab.se Olov

This message has been edited. Last edited by: OLI,

Something like the CTC AC220 or AC240 Series works well because it's sealed cable is part of the ACCEl. However, I'd replace them after a rebuild. Never use anything that requires connecting a cable. We tried all sorts of seal tight connectors, but they only works a couple of months before the wire starts getting attacked by the batch wash.

We just recently started attaching permenantly mounted transducers to the internal bearing on our Suction rolls.
We are using a Wilcoxen 797-L Transducer in the Axial position with a Wilcoxen cable running the length of the suction box coming out on the Tending side.

Later, Jason

Jason,
Thanks for the feedback!

How did you seal the penetration through the "bulkhead" at the front of the roll? Did you do the work yourselves ar was it done ba an outside vendor?

Dennis

We've been using a CTC AC122-1A which is a top exit accel with an integral cable.(I think that they've just changed the part number, and it's now something like AC102-2A/030-Z) and it seems to be going ok.

To penetrate the bulkhead, we just drilled a hole and put a cable gland on. Then we mount a BNC connector on a small switch box on the bulkhead. This gets the terminal connection external to the bulkhead.

Hope this makes sense....

Ian

Ian,
Sounds great....thanks for the feedback. I hoping we can some installed this year.
Den

The CMCP1100 series is a sealed, water proof sensor with integral cable that will work for your application. Frequency range is 0.3 Hz to 10KHz and offers high accuracy with small footprint.
http://www.reliabilitydirect.com/accelerometeraccessories/STIpdf/sti1100.pdf

http://www.reliabilitydirect.com/accelerometeraccessories/cmcp1100.htm

We have had good luck with IMI's 624A11, but I think any brand with a hermetically sealed cable will do the job.
We had an additional stainless steel tube run through the roll next to the grease line for the internal bearing and fed the cable through this then out the bulkhead.
Another thing to remember is to look for an internal bearing defect to show up in your axial reading on the tending side of the roll. I have seen the defect show up there before the internal probe showed anything.

Ken,
Thanks for the feedback. I like the tube idea. I have had some success detecting the bearing from the tending side (axial) although I thought a sensor mounted closer would be better. Maybe not!

Den

In Europe most suction roll have SPM transducers installed as attached. In earlier days an additional sealing tube was used but this has been abandoned by most users because of "difficulty to reseal after roll maintenance".

Suction_roll_monitoring.doc (246 Kb, 41 downloads) Suction roll

Roffe
Thanks for the feedback and info.
Denny

We have mounted the Accelerometer radially but from the inside of the shaft (right under the inner race) instead of axially, reading are quite low & steady but as we have not had problems yet with the bearing so I'm not sure if this is the best position.

Our Roll has the front side bearing & the rear Pilot bearing internally mounted.

Co.

Co,
Thanks for the info. I don't believe we can mount ours radially although it may be a possibility. I'll give it another look. Our operations personnel are very concerned about penetrating the front (tending side) bulkhead and potential loss of vacuum. They're questioning the ability to provide an effective seal for the cable penetration. We don't see this as being a problem although they're looking for reassurance.

Denny