Updates on replacement brass oil rings in overhung pumps with alternate material
Updates on replacement brass oil rings in overhung pumps with alternate material
(OP)
Pump users are familiar with problems of brass oil rings on overhung pumps.
http://turbolab.tamu.edu/proc/pumpproc/P22/11.pdf
We are fighting some that give us discolored oils with brass particles on some older Flowserve overhung pumps - 3600rpm, 65-70mm shaft size.
We recently found out the Trico flexible flinger line has just been discontinued this month. Apparently there was not enough demand.
There was some interesting discussion of alternative fiber reinforced composite oil rings here:
http://www.eng-tips.com/viewthread.cfm?qid=163919
As I understand the OEM now uses stainless steel oil rings in new pumps.
Not sure if installing stainless steel would create potentially worse problems (now we have brass particles in oil... but if steel o-ring should degrade it could put much more damaging particles into oil)
I'm interested in any further thoughts and experience using alternate oil rings for this type of pumps.
http://turbolab.tamu.edu/proc/pumpproc/P22/11.pdf
We are fighting some that give us discolored oils with brass particles on some older Flowserve overhung pumps - 3600rpm, 65-70mm shaft size.
We recently found out the Trico flexible flinger line has just been discontinued this month. Apparently there was not enough demand.
There was some interesting discussion of alternative fiber reinforced composite oil rings here:
http://www.eng-tips.com/viewthread.cfm?qid=163919
As I understand the OEM now uses stainless steel oil rings in new pumps.
Not sure if installing stainless steel would create potentially worse problems (now we have brass particles in oil... but if steel o-ring should degrade it could put much more damaging particles into oil)
I'm interested in any further thoughts and experience using alternate oil rings for this type of pumps.
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(2B)+(2B)' ?





RE: Updates on replacement brass oil rings in overhung pumps with alternate material
So, my preference for oil rings would be as follows (in order from best to worst):
1. Pure oil mist with no oil rings.
2. Non-metallic oil rings
3. Fixed disk flingers for bearing housings that were designed for flingers.
4. Stainless steel oil rings.
5. Brass oil rings.
Johnny Pellin
RE: Updates on replacement brass oil rings in overhung pumps with alternate material
Fixed flinger is what Floserve had recommended to us. However the flinger has to be so small (to be installable in that housing) that the oil level needs to be raised (and new seals to accommodate higher oil level). We estimate the new proposed oil level is close to middle of the lowest ball of the back-back angle contact bearings (lower on the radial bearing). Do you think that would cause problems for this application (3600rpm, 65-70mm shaft size)
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(2B)+(2B)' ?
RE: Updates on replacement brass oil rings in overhung pumps with alternate material
I don’t have any bearing housings of this arrangement running at 3600 rpm with only the fixed disks. But, I would feel comfortable installing this configuration if it was the manufacturer’s standard design. We have run into more trouble when we try to force to OEM to deviate from their standard design to satisfy our standards.
Johnny Pellin
RE: Updates on replacement brass oil rings in overhung pumps with alternate material
That said it can work as long as you have enough cooling on hand. I'd say a DE fan is a must. What are your maximum ambient and pumpage temperatures ? Also is the pump outside or not ?
A couple of other papers that might be worthy of review:
1. The original paper on non metallic oil rings that prompted Sulzer to switch http://turbolab.tamu.edu/proc/pumpproc/P17/P179-16.pdf
2. An update on testing metallic oil rings vs non metallic oil rings vs Slinger discs, that was presented at the 2014 Pump Symposium. This paper is not available online but I have a copy so if there is interest I will upload it. One takeaway from it is that slinger discs are extremely sensitive to submergence depth (to approximately the 6th power), as speed increases. If you don't achieve sufficient submergence they end up delivering very little oil.
RE: Updates on replacement brass oil rings in overhung pumps with alternate material
Valuable advice from a professor many years ago: First, design for graceful failure. Everything we build will eventually fail, so we must strive to avoid injuries or secondary damage when that failure occurs. Only then can practicality and economics be properly considered.
RE: Updates on replacement brass oil rings in overhung pumps with alternate material
It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)