High vibration in D.E.S bearing charging pump 1

[Shah g]

The bearing is 5 pads tilting pad journal bearing.clearance b/w shaft and bearing is 0.18 mm.crush is 0.02mm.(bump check method)
D.E.S bearing housing .
horizontal vib 28mm/sec
F.E.S bearing housing.
Horizontal vib 13 mm/sec.

 

[Shah g]

Only horizontal vibration is high

 

[JJPellin]

Not enough information. I could ask 20 questions but that feels like too much work. Instead, I will make a wild guess based on the last time I saw something similar.

Recently overhauled. Bearing cap was installed without dowel pins properly engaged. Bearing cap is installed off to one side resulting in much higher clearance in line with one probe and much tighter in line with the other probe. Probes are oriented at 45 degrees each side of true vertical. Horizontal probe us not oriented in the horizontal direction.

Johnny Pellin

 

[Strong]

Johnny mentioned "probes at 45-degrees of true vertical", but the OP "stated horizontal vib 28 mm/sec". I would interpret this as bearing housing measurement in Velocity units. There could be a bearing assembly issue, as mentioned by Johnny. Analyze spectrum for dominant frequency (probably 1x shaft speed) and focus on that. I suggest testing for resonant structure to identify cause of possible amplification in the horizontal direction. Also inspect for loose pump base bolts, foundation looseness, and excessive pipe motion.

Walt

 

[JJPellin]

Good points, Strong. If these are accelerometer readings, converted to velocity, I need a new theory. The vibration is probably at vane pass frequency (5 times run speed). It is a bearing bracket resonance being excited by vane pass. I have seen this several times. Add stiffness to the bearing bracket.

Johnny Pellin

 

[Shah g]

Bearing's oil feed pipe and its support have maximum vibration 200mm/s.when only loose pipe support the vib reduce to 11mm/s.but this value is in alarm one.

 

[electricpete]

High vibration in D.E.S bearing charging pump
The bearing is 5 pads tilting pad journal bearing.clearance b/w shaft and bearing is 0.18 mm.crush is 0.02mm.(bump check method

I don't understand the D.E.S. and F.E.S. Drive end and front end? What does the S stand for?
Is "charging pump" a description of the role of the pump that these bearings support? Or something different.
If you think the bearing clearance is important to the problem, can can you tell us shaft diameter? (bearing clearance seems meaningless without shaft diameter).
I've heard of "crush" in the context of sleeve bearings, bit I'm not familiar with what it would mean in the context of tilt pad bearings (if you can explain, I'd be curious to know)

Bearing's oil feed pipe and its support have maximum vibration 200mm/s.when only loose pipe support the vib reduce to 11mm/s.but this value is in alarm one.

Ok, that sounds significant.
Just to make sure I understand, would it be correct to say: "The vibration reduced from 28mm/sec to 11mm/sec on the pump when you loosened the pipe support of the attached oil feed pipe"?
If so that suggests there was a resonance on the oil pipe. Certainly a wildly swinging oil pipe is capable of causing the attached bearing housing to vibrate.
What is the frequency of the vibration on the oil pipe and on the pump? Have you tied those frequencies to likely excitation sources?
Where is the pump that provides the oil to this line (is it a shaft driven pump?). Does that oil pump have a characteristic pressure pulse frequency that matches the pipe vibration?


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(2B)+(2B)' ?