I'm getting ready to measure some differential temps on some equipment I have been aligning for a while and guessing at the thermal growth, since no one else could/would enlighten me (manufactures, and repair shops).
One question I have though, is what is the material that was (and is) used for things such as motors, compressors, and pumps. Is it cast steel? Some of the equipment is of vintage origin (say 1950) and some is newer (from 1990 up to today).

What does everyone else use?

Dave

Dave,

Cast Iron (0.0059 Mils/in/deg F) and Carbon Steel (0.0063 Mils/in/deg F) are fairly common. However, I have come across aluminum motors (0.0125 Mils/in/deg F) and pump housings that are Stainless (0.0095-0.0098 Mils/in/deg F) at times. Concrete is somewhere between Carbon and Stainless, but I don't remember what the exact number is.

I suggest a hot alignment verification afterwards, just to double-check yourself.

Take Care,

Hot alignments would be nice, I know Chris. However, that is not possible in some of these instances. I get one shot at it. Then they put Gods vibration meter on it (their hand) when it starts up. Hard to explain Thermal to some folks.
Thanks for the info.

Dave

Using a laser pin pointer to get temps or an IR camera? Take temps at multiple points from center of shaft to base and make mean calculations.

If you have 'Hot' alignment tools such as Acculign or ?????? Use them if it is cost justifible. A word of caution about across the coupling methods using laser. Use laser only on small rigid frame machines. The across-the-coupling method is invalid on large turbo machinery with pedestal bearings or large mass machines. That system doesn't measure all bearings or axial positions, etc...

<<The across-the-coupling method is invalid on large turbo machinery with pedestal bearings or large mass machines. That system doesn't measure all bearings or axial positions, etc...>>

Sam,

Could you elaborate on the above or point me in the direction where I can find more info? I'm working with a group right now that has written laser alignments into all of their aligmnent procedures. I've objected but didn't have any solid evidence to give them.

Thanks,

Bob

I'm surprised no one suggested Essinger Rods or Benchmark Gauges as manufactured by Acculign
http://www.acculign.com/
The results from these fixtures is used directly by the "thermal growth" program CSI's Ultraspec alignment set uses or free software is available from acculign.

VibrAlign has "Off Line To Run" (OL2R) fixtures for it's laser alignment system.
http://www.vibralign.com/products.html

Jon made excellent points: Essinger bars or the Acculign system can and will measure all bearings for horizontal and vertical growths and can also measure axial and piping, plus foundation if necessary. Most laser systems use only the across-the-coupling method which is poor and/or can mislead you to make false evaluations. Note: the across-the-coupling method is OK on rigid frame machine generally small machines only. We all know lasers are good and also we know that no one method fits all jobs. A laser system to measure all bearing positions and all movement is complex and expensive plus difficult although it can be done.

From a previous post; someone eluded to water cooled stands and maybe invar trusses such as used by Ray Dodd way back. The Dodd bars were across-the-coupling w/invar trusses and eddy current probes. Some have used lead-weighted stand w/water cooled legs and eddy current probes around the machines but the Acculin system is hard to beat and is economical and I think covers a very high percentage of machines that require hot monitoring.

Optics is another approach.

quote:

Originally posted by Sam Pickens:
Using a laser pin pointer to get temps or an IR camera? Take temps at multiple points from center of shaft to base and make mean calculations.

If you have 'Hot' alignment tools such as Acculign or ?????? Use them if it is cost justifible. A word of caution about across the coupling methods using laser. Use laser only on small rigid frame machines. The across-the-coupling method is invalid on large turbo machinery with pedestal bearings or large mass machines. That system doesn't measure all bearings or axial positions, etc...

Sam,

I use a Raytek gun, and measure various different points from feet to center of shaft, and take the mean. I do it both drive side and opp drive side of both machines.
However, I too would like for you to expound on the statement you continually make about a laser system not being any good for large mass machines. Why?

Dave

One end of a machine doesn't necessarily move the same as the other. In fact it may even move opposite in three planes. A long number of years ago I was talking with Charlie Jackson and he iterated to me of one machines they did had very gross numbers moving very differently from the laser's numbers - It's been a while and I'm wanting to say the difference from laser to optics (it was either optics or the Acculign system) was ~100+ mils.

Again these are fairly large machines with pedestal bearings. Naturally it's easy to see why an across-the-coupling method won't be valid unless you just got lucky but there are also machines like propane compressors that may be of one large mass but grossly different thermals from one end to the other. With their bearing housing configurations and piping configurations very different or only existing on one end; again easy to see why the machine won't respond symeterically or linearly.

And; nothing like experience - do it and see. I can recommend the Acculign system as being a very good system and affordable. It is easily plotted and can be performed as a PdM program to monitor alignment or make a quick check with the machines running to see if all is OK thus eliminating alignment as a possible cause. Jack Essigner was an Icon in the world of alignment and I hope his son will faithfully carry on the business as it is greatly needed in the process industry. Take a look at their site; the price is right!

BTW Dave; I'm in Mayretta O on a regular basis! Just in fun......long standing term about Marietta, GA home of the Kingfish.

Thanks Sam. I am going to have to gnaw on that for a while.

Dave

Remember the Amos & Andy show. Althoug Amos lived in NYC, he was from Marietta, GA. Little tidbit.

quote:

Originally posted by RRS_Dave:
Hot alignments would be nice, I know Chris. However, that is not possible in some of these instances. I get one shot at it. Then they put Gods vibration meter on it (their hand) when it starts up. Hard to explain Thermal to some folks.
Thanks for the info.

Dave

The "Gods" vibration meter... sounds alot like what I have heard also.. Others.. torque.. whats that.. good-n-tight...

Dave, been trying to a hold of you. Please email me at mikedoc at vibeassist dot com