Sign up Calendar Latest Topics Donate
 
 
 


Reply
  Author   Comment   Page 1 of 2      1   2   Next
fburgos

Sr. Member
Registered:
Posts: 463
Reply with quote  #1 
This is pump had a leaking seal, a seal and bearing replacement on pump was done on 16/june/19, what could be wrong right, i will add watter fall plot on highest vibration point of motor and pump

Pump.jpg 

this are the overall trends

Motor

img00006.png 

Pump Overall

img00007.png 


img00005.png 
img00008.png 

electricpete

Sr. Member
Registered:
Posts: 528
Reply with quote  #2 

Just some simple thoughts, probably nothing you haven’t already thought of:

It operated with fairly high vib for awhile, could have had a variety of effects in the pump.  Did they notice anything unusual when they went into the pump? 

It could have enlarged the housings. Did they check the bearing housing dimensions during bearing swap? 

It could’ve been something done during coupling/alignment.  Also I assume they would have had to remove/reinstall the hub for bearing replacement.  I'd talk to the craftsmen and ask if the hub came off and went on easy and if there was anything else unusual during these evolutions. 

Sorry, I'm not narrowing anything down. 

By the way, what kind of coupling? 

fburgos

Sr. Member
Registered:
Posts: 463
Reply with quote  #3 
Afaik it operated fairly low and steady until repair, pump impeller was in good shape, no evident cavitation.

They didn't check bearing housing dimensions.

They did remove the hub using a torch, hammer and a jack.

On June 18 misalignment was reported but supervisor sait it's not possible because they did remove the motor to make space to remove the hub but marked the position on the baseplate and it's the same as it was.

Days gone by and alignment was corrected on June 27.

it uses this "pin and bush coupling"

0_09e36d93.jpg 

MarkL

Avatar / Picture

Sr. Member
Registered:
Posts: 935
Reply with quote  #4 
Not Throwing shade on the craftsmen..but any statement including 'torch, hammer and a jack.' normally isn't good.
Did they laser align it? or am I reading wrong when the supervisor said they went by the marks they left on the back plate? Am I right in saying I see 1x and 2 x decending in the waterfall? angular misalignment? 
fburgos

Sr. Member
Registered:
Posts: 463
Reply with quote  #5 
laser alignment was carried out on june 27, you can see the drop of the 2X
electricpete

Sr. Member
Registered:
Posts: 528
Reply with quote  #6 
I apologize, I didn't read the title carefully enough to notice it's a quiz.  But looks like an interesting one.  

They thought they could make a mark and use that mark to get the motor back in alignment without actually checking alignment.   Wow. 

Does the coupling fit have a key/keyway?  (if not, it might not be unusual to have to heat it and maybe jack it although the hammer is never good).  Did the shaft or coupling bore end up scored when they pulled off this hub?  Did they remove the coupling pins and bushings during heating? Did they inspect the bushings to make sure they weren't damaged and the pins to make sure they weren't bent?  I guess they put the other end of the jack on that inboard bearing housing?  Did they check shaft TIR where the hub sits while it was off? If not did they at least check TIR during alignment   Did they measure difference the shaft to hub fit clearance/interference and the roundness before reassembling the coupling (and what was it)?   How did the hub go back on?  



vogel

Sr. Member
Registered:
Posts: 75
Reply with quote  #7 
Levels have increased all over the machine train, mainly the pump. It's all 1X, once you've already clarified the 2X appearance and disappearance.

Some posibilities:
  • Something wrong with the coupling/hub, as electricpete has mentioned.
  • Wrong bearing installation ... bearings type?
  • Reverse rotation, although I'd expect that head/flow/efficiency would decrease too clearly as to miss it for two weeks.
fburgos

Sr. Member
Registered:
Posts: 463
Reply with quote  #8 
you guys are very clever, congrats we have a coupling problem...

https://drive.google.com/open?id=1-3CwSZyCdug2Voto5s7NxK2zIacyXXyQ

MarkL

Avatar / Picture

Sr. Member
Registered:
Posts: 935
Reply with quote  #9 
I didnt realise we were being tested either!
Thats fairly dicing looking that coupling.

electricpete

Sr. Member
Registered:
Posts: 528
Reply with quote  #10 
Wow, great video!  That's not something you see every day! 

Our guys willl never pull a coupling guard off with the machine running when I ask them.  Because they don't want to get too close to rotating equipment.  Not that it makes much difference if the coupling ejects pieces like this one looks ready to do  - that flimsy guard isn't going to stop much. At least you were standing off to the pump side when taking the video, away from the likely line-of-fire of the coupling. 

Did you use the slow-mo feature of a Samsung phone?

Do you have an idea what is going on with that coupling? (other than it's obviously not good).  I can't figure out what those big flaps are.   If I had to guess I'd say it' looks like some kind of rubber sheet material coming out of what looks like a bolted flange within a two-piece hub.  Why would a coupling hub have anything like that?  Maybe for an electrically insulated coupling,  although assuming the two hubs aren't touching they are already insulated by the bushings.  Beats me. The pin and bush couplings I've seen are smaller and look like the earlier photo (one-piece hub).
fburgos

Sr. Member
Registered:
Posts: 463
Reply with quote  #11 
Yes it's slow motion videos from Samsung s9,

This is a homemade adaptation, they remove the pin bush and drill holes on the side to attach rubber bands (apparently this is a common practice on the supervisor's Homeland), I had an interesting conversation with the area supervisor on how this coupling it's better and doesn't require alignment because it's rubber, I just and said ok and align the thing 2x gone, then a lot of unbalance added a mass to partially balanced and now I'm writing a report to see if I can get the guy buy the spare bush...

What happens is this thing is not balanced at all, the rubber bends and who knows what the forces are transmitted to the hubs

Attached Images
jpeg SmartSelect_20190703-064032_QuickPic.jpg (218.31 KB, 23 views)

electricpete

Sr. Member
Registered:
Posts: 528
Reply with quote  #12 

Wow.   

Just…. Wow!!


Danny Harvey

Sr. Member / Moderator / Supporter
Registered:
Posts: 1,244
Reply with quote  #13 
I've seen something similar done with rope but on a low speed coupling. I'm betting that the flaps are conveyor belting scraps.  Ingenious but unsafe, imo.

The phrase about hammer, jack and torch told me to look at the coupling right away.  That wouldn't be done in many places in the US.
ivibr8

Sr. Member
Registered:
Posts: 133
Reply with quote  #14 
Just when I thought I had seen it all........


Can I use that picture as a part of a lesson plan on how to fabricate a flexible coupling when you are desperate?
fburgos

Sr. Member
Registered:
Posts: 463
Reply with quote  #15 
Quote:
Originally Posted by ivibr8
Just when I thought I had seen it all........


Can I use that picture as a part of a lesson plan on how to fabricate a flexible coupling when you are desperate?


only if you dont quote the source.

or if it's not patented we could be in to something.

Danny, yes its built with scrapped material, agree with you it could work flawless on low speed machines.


Previous Topic | Next Topic
Print
Reply

Quick Navigation:

Easily create a Forum Website with Website Toolbox.