Can NLGI NUMBER impact grease performance againts high temp.

What kind of bearings and what's the application?

quote:

Originally posted by micbial:
What kind of bearings and what's the application?

Dear Micbial
Roller Bearing in Palm Oil Pressing Machine.

quote:

Originally posted by Simon.:

quote:

Originally posted by micbial:
What kind of bearings and what's the application?

Dear Micbial
Roller Bearing in Palm Oil Pressing Machine.

Dear all, additional information regarding bearing type and application, TYPE timken h-414249 - h414210 for roller shaft in palm oil pressing machine. Operation temperature 180 - 220 C. Thank you.

Simon,

That could be a problem due to the fact that a 2.5 will have more solid lubricants than a NLGI 2 will, specially when you're talking about High temps and Lithium complex base. do you have access to any Calcium Sulfonate bases? They will handle much higher temps. The one from Certified Laboratories has a 70 timken load and 1000+ kg on 4ball weld. It also handles 550deg(f)

www.certifiedlabs.com

also, mixing greases with different thickeners can cause a problem if the thickeners are not compatible. You could do a worked penetration test of the two to see if they are in fact compatible. Also of course it would be helpful to examine the failed bearing including remaining grease.

Hello Simon,

Is your bearing the one in the screw press? I doubt the percentage of thickener will make such a big difference.

We've been to most of the Palm Oil Mill in thailand and had in fact consolidated and came out with a brochure specific for this industry. If it is on interest to you, drop me an email and I can forward a copy to you.

Regards,
Kai

quote:

Originally posted by Simon.:
Dear All,
My customer uses NLGI 2.5 (worked penetration 255) lithium complex grease to lubricate their high temp bearing grease about 180 C operating temperature. The lubrication interval is about 2 - 3 days for 24 hours running. Accidentally my office sent NLGI 2 (worked penetration 265 - 280), from the same brand and same type grease (only the nlgi is different).

Bearing failure was reported for 1.5 days operation. Is it possible because of using the lighter NLGI? and how to determine the causes of the bearing failure in this case? Please advise. Thank you.

Dear All

Thank you for all replies. The last update from the end-user, NLGI 2 seems work well. They are forced to use this NLGI because the new stocks will be arrived on august : )

Honestly, I still don't understand whether the failure due to NLGI or other causes.

Regards,

Simon,

Was the base oil viscosity (normally rated at 40C) the same for both the greases?

Grease is mainly made up of base oil (anywhere from 85% and upwards), soap or thickener and additives (including solid additives).

Being mainly made up of base oil, it's the base oil that does most of the lubrication, therefore, just like lube oil application, base oil viscosity is very important.

quote:

Originally posted by LumSK:
Hello Simon,

Is your bearing the one in the screw press? I doubt the percentage of thickener will make such a big difference.

We've been to most of the Palm Oil Mill in thailand and had in fact consolidated and came out with a brochure specific for this industry. If it is on interest to you, drop me an email and I can forward a copy to you.

Regards,
Kai

quote:

Originally posted by Simon.:
Dear All,
My customer uses NLGI 2.5 (worked penetration 255) lithium complex grease to lubricate their high temp bearing grease about 180 C operating temperature. The lubrication interval is about 2 - 3 days for 24 hours running. Accidentally my office sent NLGI 2 (worked penetration 265 - 280), from the same brand and same type grease (only the nlgi is different).

Bearing failure was reported for 1.5 days operation. Is it possible because of using the lighter NLGI? and how to determine the causes of the bearing failure in this case? Please advise. Thank you.

Dear Kai, I am glad to have your reply and your offering to share your experience in PALM OIL MILL by forwarding the information you have. You may email me to simon.mybusiness@yahoo.com Thank you very much.

quote:

Originally posted by ReneWA:
Simon,

Was the base oil viscosity (normally rated at 40C) the same for both the greases?

Grease is mainly made up of base oil (anywhere from 85% and upwards), soap or thickener and additives (including solid additives).

Being mainly made up of base oil, it's the base oil that does most of the lubrication, therefore, just like lube oil application, base oil viscosity is very important.

Hi ReneWA, the base oil viscosity 40C is 116, both are the same. How come the base oil viscosity 40C can impact the performance of the grease againts the high temperature? Based on my knowledge, the base oil viscosity will influence the grease performance againts speed. Higher speed, lower base oil viscosity. Am i right? Please advise. Happy today

Simon,

You are right regarding matching the viscosity of base oil in grease and the operational temperature. Personally, I don't think that the failure is caused by grease of 0.5 lower NLGI grade than what was used before. It may affect the overall longevity of bearing but not to shorten its life so drastically. I would rather look at possible grease delivery issues– lack of it (possible air pockets?) or even over greasing which could be deadly even more deadly for this bearing. However, I have been wrong before, and therefore, you might send failed bearing to Timken. They have an excellent database of failure studies and can tell you with great certainty what caused the failure.

Hi Simon,

Try this principle, smaller amounts of lubricant applied more often results in better lubrication and lower overall maintenance cost.

Suggest to relubricate daily with smaller volume.

Or suggest to use Memolub lubricator.

MEMOLUB prevent bearing failure by providing the right amount of lubricant (cartridge - clean/fresh) at the right frequency to the right place all the time. By keeping the grease in optimum level the bearing is sealed from contaminants, there`s no overheating, no under / over lubrication.

"Bearing failure was reported for 1.5 days operation. Is it possible because of using the lighter NLGI? and how to determine the causes of the bearing failure in this case? Please advise. Thank you."


Hi Simon

As you can see from the replies before the general thoughts are that a failure should not have happened,
what happened to the bearing?,
have you seen the bearing?
was the failure root caused?
Always the lube gets blamed and often with out checking the actual failure mode.

Regards

Rob S

Hello everyone.

Reading all the answers has been a very educative experience. I do say thanks for all the answers.

May I, or may We suppose that the difference in the thickener amounts between these 2 greases with the same oil and the same additivation level is enough to lead to a failure?

Why?, The tridimensional structure provided by the thickener was weaker? Was not able to handle the amounts of heat presented? Was not able to hold in a proper way the lubricant? Was not able to recapture it once it had released it? If the thickener was not able to retain the lubricant, in that temperature, total losing of the lube was enpough to let the bearings unlubricated and then lead to total failure?

On the other hand, It seems to me that operation temperature is extremely high for a lithium complex grease, (You should take a look to clay thickener) bearing in mind that dropping point is aroud 260 C and you must take near 80 C degrees to get a reliable performance, it is possible that the problen arise long before this "mistake".

Dear Simon,

You need specialty Hi-Temp grease with synthetic thickener.

Dear All,


I would like to say thank you for your input response and answer. The problem already solve, and I have new contacts and friends from this forums.

I wish u all the best. Good luck.

My best regards.

Interesting, how was the problem solved? Also in view of the many suggestions I would like to add my two cents.

First, while there is no official NLGI Grade 2.5 some companies offer it when they do not have a Grade 3. Typically you want a stiffer grease at high speed when you want the grease to stay out of the way of the rolling elements. A Grade 3 can also be used with vertical arrangments to stop the grease from slumping too much, otherwise you have to put in an antislumping plate or shield (not a seal) on one side. Given that the Grade 2 was the same type then the thickener, baseoil and additive issues are not relevant.
However, you did not provide the operating speed, the arrangement (vertical or horizontal, the load or how long the bearings last normally. More importantly there was no info on how the bearing failed.
If it was a new bearing perhaps there was just no grease before installation or not enough grease was pumped in intially or if an existing bearing did they pump in too much grease and not allow the excess to escape.
So to make relevant comments we need more info. But a stiffer grease does not make it a high temperature grease. And a thicker base oil does not make it a high temperature grease either. You have to take into account the base oil viscosity index, oxidative stability, volatility, oil separation and because this might be heavily loaded, the EP and antiwear characteristics. Given that it was a lithium complex the dropping point should not be an issue but because of this thickener a stiffer grease might not be better. With calcium sulphonate thickeners some of the EP characteristics are imparted by the thickener so stiffer might be better.

Ken

I like the answer about reducing re-greasing quantities. The bearing should be about 1/3 full. Over-filling the bearing can prevent heat dissipation.

quote:

Originally posted by Simon.:
Dear All,


I would like to say thank you for your input response and answer. The problem already solve, and I have new contacts and friends from this forums.

I wish u all the best. Good luck.

My best regards.

Dear Simon,

Can you share how the problem was solved? curious, I once faced the wheel bearing problem of a truck, used NLGI 2 grease, the grease all became very liquidity after few days, still don't know what happened.

Thanks.

ah hao:
Your problem sounds like a compatibility issue. There are two basic aspects to grease, NLGI grade & soap chemistry. (Yes, base oil vis, type & additive chemistry matter, but the wrong base oil or adpak is more likely to result in reduced bearing life than catastrophic failure.)
If you mix two greases with incompatible soaps, usually the soaps break down and won't hold the oil, which makes your NLGI 2 act like an NLGI 0 or 00. (Sometimes they stiffen up and act like a 4 or a 5, but that's much less common.)
Always re-grease with the same soap-type. If you're not sure what was in there, you need to get every last blob of the old grease out of the bearing before re-greasing. If you can't do either, you just have to keep re-greasing until you've displaced all of the old grease (not much fun on a wheel bearing). Good Luck!

I don`t believed that the problem was solved, in the first place, it uses the wrong product and wrong frequency for the application. If your bearing does not reach at least 2 years you have problem.

This thread https://forums.noria.com/eve/fo...5/m/752107841/inc/-1
is related to this topic

quote:

Honestly, I still don't understand whether the failure due to NLGI or other causes.

I think my previous comments still apply (see above). There is a difference between using NLGI2 and mixing NLGI2 with a grease that has another thickener. The results of mixing are unpredictable unless you have tested them.