Seals
- Thread starter MolaKule
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Has Amsoil TSO had any seal compatiblity issues?
MolaKule
Staff member
Not that I am aware.
If you have bad seals already, a synthetic fluid will be more apt to clean the sludge and leak past a bad seal.
If you suspect sludge or poor seals, try Auto-RX.
If you have bad seals already, a synthetic fluid will be more apt to clean the sludge and leak past a bad seal.
If you suspect sludge or poor seals, try Auto-RX.
"Which of the following components has the potential to attack seals..?"
You forgot to list "Eskimos" and "wooden clubs."
You forgot to list "Eskimos" and "wooden clubs."
MolaKule
Staff member
Now back to the original question
Radial lip seals fit snug enough around the shaft so that only a very small controlled amount of lubricant or other fluid can seep past and lubricate the shaft to seal contact, I would think the surface tension of the fluid being sealed would play a role in how well the leakage would be controlled coupled with the clearance. But there has to be a small amount of leakage to lubricate the seal on the rotating shaft.
When we need seals from stock at the plant for rebuilds and such, I normally just go to the CR handbook and match the seal to the shaft size just to make sure the wrong seal wasn't previously installed.
The wedge facing the fluid being sealed I believe is to act as sort of a squeegee diverting fluid away from the opening.
When we need seals from stock at the plant for rebuilds and such, I normally just go to the CR handbook and match the seal to the shaft size just to make sure the wrong seal wasn't previously installed.
The wedge facing the fluid being sealed I believe is to act as sort of a squeegee diverting fluid away from the opening.
MolaKule
Staff member
OK, Mr RB Shannon is converging on the core of the question.
MolaKule
Staff member
Mr Shannon was very close.
Radial Lip Seals actually "pump" the oil from the outside to the sump by having a defined geometry of oil underneath the seal and between the seal and shaft.
Experiments have been done in which a few drops of oil had been placed on a rotating shaft just ouside of the seal. The seal actuallly moved the oil from the outside to the sump.
Radial Lip Seals actually "pump" the oil from the outside to the sump by having a defined geometry of oil underneath the seal and between the seal and shaft.
Experiments have been done in which a few drops of oil had been placed on a rotating shaft just ouside of the seal. The seal actuallly moved the oil from the outside to the sump.
I just got off work and I'm pretty tired,I'm not sure I understand.
The oil placed outside the seal(the flat side) gets pumped towards the cup side? Is my understanding correct on this?
The oil placed outside the seal(the flat side) gets pumped towards the cup side? Is my understanding correct on this?
I actually found some info on the net, but I wasn't sure how to word it.
http://www.eng-tips.com/gviewthread.cfm/pid/819/qid/83689
-T
MolaKule
Staff member
You are correct. This squeege or pumping action is due to a number of factors:
1. Lip tension (provided by garter spring)
2. Lip geometry,
3. Oil film geometry under seal lip.
This action is indicative of most lip seal designs.
In terms of seal cross section, think of the radial lip seal in terms of the arm and hammer guy on the box of soda. The arm supports the fist, where the fist's knuckles ride on the shaft with a film of oil underneath the knuckles. A slight back-and-forth motion of the knuckles on the shaft coupled with the actual geometry of the seal contact point AND the oil wedge underneath, give rise to a pumping action TOWARD the sump.
I previously worked for a seal manufacturer on the manufacturing engineering side, not the design side, but as I recall, the class of seals that pump oil have what is termed a radial helix lip design.
The helix is a series of minor spiral ribs that stop just short of the lip contact point. The ribs are slightly compressed & decompressed as the seal lip follows the eccentricity of the shaft. This effect is similar to a positive displacement pump & the film of oil between the shaft & sealing lip is pumped back to the fluid side.
As I remember, the helix was specific for shaft rotation direction. Bi-directional helix's would work in either direction, uni-directional designs would pump fluid out if used in the wrong application.
Radial lip seals actually require a thin film of the fluid on the shaft surface at the lip contact point. Highly polished shaft finishes will cause a seal lip to burn up as the oil in microscopic peaks & valleys of a 20-30 RMS shaft finish is necessary for lubricating the sealing lip.
The helix is a series of minor spiral ribs that stop just short of the lip contact point. The ribs are slightly compressed & decompressed as the seal lip follows the eccentricity of the shaft. This effect is similar to a positive displacement pump & the film of oil between the shaft & sealing lip is pumped back to the fluid side.
As I remember, the helix was specific for shaft rotation direction. Bi-directional helix's would work in either direction, uni-directional designs would pump fluid out if used in the wrong application.
Radial lip seals actually require a thin film of the fluid on the shaft surface at the lip contact point. Highly polished shaft finishes will cause a seal lip to burn up as the oil in microscopic peaks & valleys of a 20-30 RMS shaft finish is necessary for lubricating the sealing lip.
This makes sense to me now! At the plant we have a lot of gear and bearing boxes that get contaminated with water, I use to think it was mostly happening during sanitation but with this explanation I can see it happening during production time, maybe even more so. On our colloid mill bearing boxes they used to have stainless slingers in front of the oil seal on the shaft to protect it from the water cooled product seal, most of these were removed by request of processors because of the annoying ringing at shut down but I can see this was a big big mistake. I'll have to bring this up so that they can get the same glassy stare
as when I talk about oil and grease.
MolaKule
Staff member
Edemucate them RB, and don't let the the stares get to you.
It sounds like the slingers need to be reinstalled. They were put there for a purpose.
It sounds like the slingers need to be reinstalled. They were put there for a purpose.
MolaKule
Staff member
There a number of Dynamic Efects that can cause seal leakage of radial lip seals.
Of the 13 causes, one of them is Lubricant Degradation such as sludging.
Please name the other 12 causes.
[ May 22, 2004, 01:44 PM: Message edited by: MolaKule ]
Of the 13 causes, one of them is Lubricant Degradation such as sludging.
Please name the other 12 causes.
[ May 22, 2004, 01:44 PM: Message edited by: MolaKule ]
1, excessive clearances.
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