Self sealing shaft seal.

[Grizzly]

Hi Guys.
I recently assisted another Engineer to change a STAL shaft seal (Mini screw).
3 weeks later the customer phones advising that the seal is leaking!!!
4 days later shaft seal not leaking!!
Any ideas?
Grizzly

[RANGER1]

Grizzly ,
When you say leaking how much exactly?
Was it just leaking oil , or gas .

Maybe in a couple more weeks it will also tell the tale !

In Howden litrature is claims they have a break in leakage rate of 200 hrs , then an acceptable leakage rate .

[That's too cold]

Compressors that are off for along period of time, the oil will partly drain from the shaft seal causing a small leak to occur. This can apply to screws and recipes shaft seals. Oil plays a critical role in keeping a shaft seal from leaking. I have seen recipes with closed suction and discharge valves with excess pressure blow ***** out the shaft seal.

[Quality]

Hi Guys.
I recently assisted another Engineer to change a STAL shaft seal (Mini screw).
3 weeks later the customer phones advising that the seal is leaking!!!
4 days later shaft seal not leaking!!
Any ideas?
Grizzly

Bloody whats its name I want to buy a self sealing shaft seal

On serious not I have not worked with stal comps to much but a shaft seal is a shaft seal and do require a bedding in period as I am sure you know, keep us posted

I have done 4 seals on one compressor in less than a year recently on newish kit.Then managed only just to convince the customer that a strong smell is a small amount if they are able to bear it. After 8 - 10 weeks they have either got used to it its not leaking

I Hope

[Grizzly]

OK Guys!
As has been said a shaft seal is a shaft seal.
All the usual points were fastidiously adhered to.
Like ultra cleanliness and copious amounts of oil even down to wet and drying any shaft defects.
Which is why when told last week that the Shaft Seal was leaking. I was amazed.

All I could advise at the time was for the site engineers to call the shots as to whether they shut down or isolate the compressor.

Anyway as said on Monday morning I get a call direct from the Site Engineer.
Whereas last week I was not contactable by phone. (One of those sites where a phone is not allowed!!)

He informs me that despite the shaft seal leaking Ammonia Vapour and oil badly last week it had now stopped and there was no need for me to schedule a site visit?

I don't have any more details as of yet, when I next get the chance I will ask more questions.

Maybe the viscous seal did dry out and restarting resealed it?

If that is the case I would expect it to start leaking again at some point?
Maybe it is a case of time will tell.

I have experience seals that flat spot but not when the lateral tolerances where acceptable and the seal was so new.

I told the Engineer that I was not sure as of yet, maybe the seal picked up a bit of crud or something.

Grizzly
Cheers Grizzly