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Xracer

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Reply with quote  #1 
Sorry if this question is posted in the wrong area.
I'm trying to find/locate a standard classification of oil seal (lip seal) leakage. In general for gearboxes. If there a "standard" Guide line etc?

Thanks,

X
Walt Strong

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Reply with quote  #2 
Did you try a search like this:

https://www.bing.com/search?q=classifying+lip+seal+oil+leakage&form=EDGEAR&qs=PF&cvid=accff72dd215472882d65bb8fa29a76a&cc=US&setlang=en-US&elv=AY3%21uAY7tbNNZGZ2yiGNjfMen3X6RQpRuScmgVSFsvglve9OuUy9wRdxni0y5yzGSaUGbejuBs58fSGKOoSgf8o14oUf*zL0DI7tzkqE5MbR

Sorry no specific help.

Walt
MarkL

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Reply with quote  #3 
Seriously I am not being a smart ass here but surely its simple as 
'Leaking'..or 'Isn't leaking' 

Especially in the case of gearboxes, it would suggest shaft movement, dirt ingress dislodging the seal or also the wrong oil being added, a Polyglycol wont play nice with most other oils and sometimes can also eat away seals. I've also heard that Pao oils can cause shrinkage of seals that were formerly in contact with mineral oil., both occurrences undesirable. when I conduct inspections on machines as part of my route I emphasize this heavily.
Walt Strong

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Reply with quote  #4 
I thought perhaps there would be some Golden Nugget in the link I provided. Perhaps John PA will have better information for OP.

Walt
MarkL

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Reply with quote  #5 
John Probably will he’s good at that sort of thing he’s an endless resource.

I wasn’t being disparaging earlier just there are Certain hings I question the requirement of standards on some things.
Xracer

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Reply with quote  #6 
Quote:
Originally Posted by MarkL
Seriously I am not being a smart ass here but surely its simple as 
'Leaking'..or 'Isn't leaking' 

Especially in the case of gearboxes, it would suggest shaft movement, dirt ingress dislodging the seal or also the wrong oil being added, a Polyglycol wont play nice with most other oils and sometimes can also eat away seals. I've also heard that Pao oils can cause shrinkage of seals that were formerly in contact with mineral oil., both occurrences undesirable. when I conduct inspections on machines as part of my route I emphasize this heavily.


Mark,

I know what your saying.. As I consider is leak.. no leak.. as simple as that..

But, to others, one has to further define what is considered a "leak".

To me, if there is oil in the area of the seal, but hard to see due to guarding, then its likely leaking from the seal. If seal is dry, or no traces of oil exiting from seal, then its not leaking..

X
electricpete

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Reply with quote  #7 

I don’t think it matters what you call it (where between one drop per second and one drop per year does it stop being a leak), but you have to decide if you want to fix it or not. 

 

The different ways to attack the question of whether or not you will fix it:

1 – What are the potential negative effects of the leak?  (will it drop on any sensitive components inside the component like the motor winding, will it drop on sensitive components outside like wiring/electronics, will it create a slip hazard for personnel, will it create a fire or explosive hazard, does it create a burden for cleaning up the external oil, will it empty the reservoir in so short a time that it creates an excess burden refilling the oil... or worse yet we don’t refill it in time to prevent equipment damage, do we have confidence the leakage rate is stable).

2 – How difficult would it be to fix the leak?

3 – Is this type of leakage more than the seal was “designed” for?

4 – What do standards say about leakage?

 

Comparison of 1 (potential negative impact) vs 2 (cost to fix) really should have the most practical influence on any decision. But there may be some unknowns involved, so we might resort to 3 and 4 to help tip the scales of the decision.


So yes I can see asking about standards as a relevant question.

No, I don’t have any standards handy. Haha, all those words to say I don't know.

John from PA

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Reply with quote  #8 
With respect to gearboxes are you dealing with a machine having rolling element bearings or fluid film bearings?  A gearbox with rolling element bearing will most likely have some lip seal or mechanical seal arrangement.  Gearboxes with fluid film bearings will generally have labyrinth seals.

I don't have any personal experience with API 682 but based on the link https://www.flowserve.com/sites/default/files/2016-07/API682.pdf you might be able to find something worthwhile in terms of general information (lip seals) within that specification.  You might also check http://fluidsealing.com/sealingsense/may08.pdf, again general info.  See page 2, the Leakage Rates section in particular.
John from PA

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Reply with quote  #9 
Quote:
Originally Posted by MarkL
John Probably will he’s good at that sort of thing he’s an endless resource.


Perhaps I should add my address to my signature or open a "go fund me" account.  [biggrin]
Xracer

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Reply with quote  #10 
Quote:
Originally Posted by John from PA
With respect to gearboxes are you dealing with a machine having rolling element bearings or fluid film bearings?  A gearbox with rolling element bearing will most likely have some lip seal or mechanical seal arrangement.  Gearboxes with fluid film bearings will generally have labyrinth seals.

I don't have any personal experience with API 682 but based on the link https://www.flowserve.com/sites/default/files/2016-07/API682.pdf you might be able to find something worthwhile in terms of general information (lip seals) within that specification.  You might also check http://fluidsealing.com/sealingsense/may08.pdf, again general info.  See page 2, the Leakage Rates section in particular.


These would be gearboxes with rolling element bearings..
John from PA

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Reply with quote  #11 
Seals are a critical part of the machine; if oil can get out then external contaminants can get in.  In my experience seals are much like bearings in that a high number of failures are due to incorrect installation practices; not necessarily from the factory build but later on when overhauled.  One excellent reference on seals can be found at http://www.rlhudson.com/media/RLHudson-Shaft-Seal-Guide.pdf.  The document is a wealth of seal information but I would suggest you especially look at page 197+ as it addresses gearbox seal design.
Xracer

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Reply with quote  #12 
Thanks for the replies. The info will help in setting up classifications of "leaks"


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