Why fretting corrosion happens in particular seals only?
Why fretting corrosion happens in particular seals only?
(OP)
Dear All,
Why fretting happens in particular seals only? For example, In a process industry, if we have a hundred seal almost 80% of the seal's secondary seals contacts the shaft/sleeve. But only in particular seals failure happens due to fretting at the shaft/sleeve.
One more intresting thing is, If it is a double seal, I/B seal fails due to fretting but the O/B does not?
How to avoid fretting? Is fretting associated with the pumping fluid? Is the fretting vulnerable in high pressure application?
Please drop your valuable answers.
Thanks to all.
Why fretting happens in particular seals only? For example, In a process industry, if we have a hundred seal almost 80% of the seal's secondary seals contacts the shaft/sleeve. But only in particular seals failure happens due to fretting at the shaft/sleeve.
One more intresting thing is, If it is a double seal, I/B seal fails due to fretting but the O/B does not?
How to avoid fretting? Is fretting associated with the pumping fluid? Is the fretting vulnerable in high pressure application?
Please drop your valuable answers.
Thanks to all.





RE: Why fretting corrosion happens in particular seals only?
RE: Why fretting corrosion happens in particular seals only?
How to avoid? Consider seals that do not use dynamic elastomers such as a bellows type seal or maybe a seal with a spring mounted stationary face.
RE: Why fretting corrosion happens in particular seals only?
Thanks for your Post. As Mr.JJ mentioned, it was happened on the ApI 53 plan seal. The Pump has two Seals. On Drive end we find heavy fretting at I/B seal (diametrically,deep groove for 60% and relatively lesser at another 40%)and no fretting at O/B.
On NDE O/B seal got heavy fretting compared to I/B seal.
On all of these, DE's I/B seal got deepest and uneven grooving.
Really,we hadn't check the Stuffing box run out / face out due to urgency of the pump. Next time, sure I will check it.
As Mr.Bin said, I will discuss with my superior about the ceramic coating.
I wish you all have a Merry Christmas and Happy New Year.
RE: Why fretting corrosion happens in particular seals only?
I also also seen this happen on seals where the shaft is whirling or bent due to the hydrodynamic loads inflicted on the pump.
More movement on the inboard seals than the outboard seals and this is what you are witnessing on the fretting front.
It is also advisable to go for stationary seals and have the O rings on top of the faces rather than underneath them.
I have a drawing of a typical seal you could use if you want me to PM it.
RE: Why fretting corrosion happens in particular seals only?
Yes, it is vertical split liquid ring vacuum pump.
It will be definitely helpful to me if you could send me that drawing. How could I contact you? please give me the details. Sincere thanks to you.