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In a previous location, we changed out our mineral oil in cooling tower gear boxes annually until we started doing oil analysis. With the analysis program, we got at least two years out of the oil. What is the condition of the gearboxes you are having overhauled? Is this a circulating system? What kind of filtration is fitted (if any)? If you are getting significant wear in the gears, then change oil to something besides an R&O oil.

Ken Culverson
RM
Actually condition of oil is not consistent in all the G.BS. Some have only discolouration, while others have high moisture (upto 740ppm)and deposits.

Condition of bearings is also varing. Though we can run them upto 3 years or even more (Amarillo Says to replace after 5 years), but we change them every 2 years. I mean half of the gearboxes are overhauled one year and rest in the next year.

Whats your experience with mineral oil Morilna150 and bearings replacement.

One maint manager told me that he doesn't change their G.Bs bearings until they start producing noise.
RM
Yahoo,

I worked in a Petrochemical Plant for 6 years, during that time our Gearbox (Amarillo)overhauls were based on Oil & Vibration analysis. We had some 18 Cells in total and operated these without routine O/H or oil Change. If memory serves me right, we replaced bearings on a couple of G/B but, we had fan blade lamination peeling off after 2 years.

Regards...Rajan
RM
Hi guys
I am currently working in a fertilizer plant. We have 1o cooling tower cells. The fan gearboxs installed are amarillo 1713A.

The problem is that we have to change oil every 2500hrs (the oil is contaminated) and overhaul gearbox every 1.5yrs due to poor condition of the gear boxs.

We are considering using syntheic oil. Currently we are using shell morlina 220.

I need your experienced advised on the matter.

Regards
Ahmed
RM
Some tips based on being with a cooling tower manufacturer for many years.

Water in the oil is a common issue and use of synthetic oil is a potential remedy for extending oil change intervals. Having said that I know of many people that take the cap off the lowest bearing on the vertical shaft (check your cross section) and run a small line "outside" the tower (see attached). Very often a drain plug even exists but if not, use care in removal of the cap as it may control a bearing setting. After a unit has been shut down for several hours or more, a small sample of liquid is drained off, and of course replaced as needed. You will often find this liquid sample to be high in water and even debris. Pulling some of this off on a regular basis will help extend the life of the bearing.

That particular bearing, usually the bottom bearing of the intermediate shaft or the first reduction gear shaft, is very often the first to go allowing the gearing to run "off axis" and cause severe secondary damage to the gearing.

Attachments

RM
What is the contamination?[/QUOTE]

Hi Mark usually Dirt and water but dirt is the major player, there are about 40 cells on one of the sites we look after but only 3 cells are being oil sampled, usually it's VA that notifys of abnormal wear but by the time VA can "see" it damage is already occurred, most tower drives are a spiral bevel drive so gear mesh frequency will elevate because of fine hard particles being pulled through the gears, we'll see the dirt ingress on the microscope and change the lubricant and the gear mesh frequency will slowly return to normal as the drive polishes out the fine hard particle damage, we are installing a unidirectional breather system that will lightly pressurise the drives @ 2" of water pressure (0.1 PSI)which should keep the water and dirt out, Regards
Rob S
RM
quote:
Originally posted by rttech:
What is the contamination?


Hi Mark usually Dirt and water but dirt is the major player, there are about 40 cells on one of the sites we look after but only 3 cells are being oil sampled, usually it's VA that notifys of abnormal wear but by the time VA can "see" it damage is already occurred, most tower drives are a spiral bevel drive so gear mesh frequency will elevate because of fine hard particles being pulled through the gears, we'll see the dirt ingress on the microscope and change the lubricant and the gear mesh frequency will slowly return to normal as the drive polishes out the fine hard particle damage, we are installing a unidirectional breather system that will lightly pressurise the drives @ 2" of water pressure (0.1 PSI)which should keep the water and dirt out, Regards
Rob S[/QUOTE]

I was going to suggest a Air Sentry Breather
RM
Hi All,

Interesting to see the time frame this thread covers... In any case, one solution for oil contamination is offline filtration. We (C.C.JENSEN) supply kidney loop filtration units for gearboxes which remove water, particles, sludge, and varnish. Filtration is to 3 micron absolute and we have seen good results with this specific application for cooling tower gearboxes. If anyone is interested in additional information feel free to drop me a line.

See below links of case studies:
https://docs.google.com/file/d...ZkE/edit?usp=sharing

https://docs.google.com/file/d...ZFU/edit?usp=sharing

-Perry

perry@klassenhydraulics.com
RM
We have 20 Amarillo double-reduction gearboxes on cooling tower fans. All were originally equipped with a drain line extended outside the fan cell to the oil level gauge, and a vent line off the top of the gearbox, also extended outside of the fan cell. We've added a "fill" line to the top of the gearbox, as well as desiccant breathers on the vent line. Desiccant breathers should have check valves to help extend the life of the desiccant. Twice per year we are using filter carts to circulate oil via drian/fill lines for about 25-30 minutes per gearbox with 10 micron filters and water removal filters. We pull oil samples at this time. Oil is SHC 630.

Thus far we've ran the oil in most of our gearboxes for about two years. Oil samples results indicate good oil condition; although the oil typically does appear dark. I plan to begin having oil replaced in most gearboxes next year due to high particle counts in the 4 and 6 micron ranges. There was some speculation about whether to use filters under 10 micron due to possibility of stripping out defoamant; therefore, we haven't gone below 10 micron filtration yet. We may try using 3 micron filters on a few. I was told by Noria that there is a risk of stripping out defoamant, but a 10 micron filter will do about as much damage as a 5 micron filter. I guess we'll see.
RM
Hi bsparks,

I would be interested in hearing what Noria's basis is for saying fine filtration will strip out defoamant. There are many Amarillo gearboxes out there currently running with CJC 3 micron filtration. Outside of the Amarillo brand we have continuous filtration on thousands of gearboxes and don't have a problem with removing additives.

The smallest particles are the most damaging that is why CJC has implemented 3 micron (absolute) for filter elements. Also you will see much better results by installing permanent filtration on the gearboxes rather than performing sporadic filtration with filter carts.

Let us know how things progress.
RM
Here are some comments from Amarillo regarding CJC filtration:

Does the filter blindly strip out the additives in my oil?

No. Some additives exist in the oil and are considered sacrificial. That is they attach themselves to very small particulates to enhance their size so that they can be removed by filtration. Once filtration begins, the particle is removed from the oil causing a reduction in particle count and additive concentration. The additive has done its job, as well as the filter. In most cases some additives will decline slightly and level off. This is expected. A different form of additive, additives in solution, cannot be filtered out simply because they are so small. Furthermore, the majority of additives are submicron and cannot be filtered out.

http://www.amarillogear.com/gearbox_service_unit.php

Amarillo's Gearbox Service Unit (GSU) is a CJC filter mounted on a cart for portable servicing.
RM
quote:
Originally posted by John from PA:
Some tips based on being with a cooling tower manufacturer for many years.

Water in the oil is a common issue and use of synthetic oil is a potential remedy for extending oil change intervals. Having said that I know of many people that take the cap off the lowest bearing on the vertical shaft (check your cross section) and run a small line "outside" the tower (see attached). Very often a drain plug even exists but if not, use care in removal of the cap as it may control a bearing setting. After a unit has been shut down for several hours or more, a small sample of liquid is drained off, and of course replaced as needed. You will often find this liquid sample to be high in water and even debris. Pulling some of this off on a regular basis will help extend the life of the bearing.

That particular bearing, usually the bottom bearing of the intermediate shaft or the first reduction gear shaft, is very often the first to go allowing the gearing to run "off axis" and cause severe secondary damage to the gearing.



Our plant is Power plant where we use 14 Cells Cooling tower. All 14 cells cooling tower gearbox lubrication oil is Servo system 100(Mineral oil). Now i would like to go for synthetic oil, will i conserve energy of Motor., Will i able to reduce my Auxillary power consumption by adapting synthetic oil. Can any one comment on this if they experience.
RM

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