What should be the maximum permissible limit for TAN (Total Acid Number) if tested by KOH neutralization method, for any Industrial Lubricant.

Xi’an TianHou Electronic-Technology Co., Ltd is the leading supplier and manufacturer of oil quality analyzers in China. After established in 1992, THY series oil quality analyzers won praised by insiders in lubrication management.
THY series oil quality analyzers have realized lubricant replacement according to quality. In 2000, THY-20C passed technology achievement appraisal by Lanzhou Military Command. In 2001, it won the second prize for technology progress in the military system of China and national patents which including one invention patent and three design patents. It introduced CIS in the same year. In 2002, the company passed Hi-tech Enterprise Authentication.
Oil quality analyzer detects and measures the dielectric constant of oil. By measuring the complex dielectric constant of oil, it is able to determine the degree of change in the dielectric constant of the oil. Dielectric change is directly related to the degradation and contamination level of the oil and helps the user to optimize intervals between oil changes and to detect increased mechanical wear and loss of the oils lubricating properties.

To guarantee the quality, we have established and perfected quality guaranty system. In 2001, we got ISO9001:2000 certificate. We sticks to firm and standard quality control in production process and carries out modern management. It attaches much attention to employee education and comprehensive enterprise character.

Contact us:
Company：Xi'an Tianhou Electronic-Technology Co., Ltd
Address ：A 1506 Room, Shuangyu Building, West Yanta Road, Xi'an City, China
Zip code：710061
Tel ：86-29-86691978 Fax ：86-29-85215296
Website : http://www.english.oil8.com E-mail：sales@oil8.com

quote:

Originally posted by Davis:
... Dielectric change is directly related to the degradation and contamination level of the oil and helps the user to optimize intervals between oil changes and to detect increased mechanical wear and loss of the oils lubricating properties...

Baloney or hogwash, whichever you like better! Your test results points to nothing. There is absolutely no way to identify with any degree of certainty which parameter caused dielectric change. Is it wear, or ingressed contaminants, or loss of additives, or something entirely different. And BTW, you did not even try to answer the posed question. Shame on you, cheap peddler!

A.S. Pal, in order to get an answer to you inquiry, you need to be more specific; e.g. which oil is of you interest? Is it motor oil, turbine oil, hydraulic oil, gear oil, transformer oil, or something else? There are no universal limits that would apply to all oils. However, there are some role-of-thumbs out there, but eventually, end-users set their own limits for a particular oil.

A.S. Pal, in order to get an answer to you inquiry, you need to be more specific; e.g. which oil is of you interest? Is it motor oil, turbine oil, hydraulic oil, gear oil, transformer oil, or something else? There are no universal limits that would apply to all oils. However, there are some role-of-thumbs out there, but eventually, end-users set their own limits for a particular oil.[/QUOTE]

Mr. John Micetic
I am interested for, in service, Industrial and Automotive Lubricants.
Somebody told me that, if you want to get the max. permissible limit for TAN, for any lubricant, then, I first find out the TAN value of fresh lubricant. Whatever is result, just add 1 or 1.5 depending on the criticallity of the equipment and its component. The end result will be the max. permissible limit.
Is it true ??

Dear Mr. pal,

To add 1 and 1.5 to the basic TAN is a general thub rule.
However,TAN of the fresh oil is due to some additives,will decrease initially due to the depletion and then the original TAN due to oxidation will start to increase and this TAN will be dangerous for the equipments and the system.
To my knowledge,for industrial lubricants,the above values are critical.But for engine oils,the limits are different.

K. M.'s post elaborating on TAN issues is correct. You can use the suggested rule of thumb (for setting your TAN limits for industrial oils). However, my advice is to at least yearly run ASTM D 2112, Oxidation Stability Test. Then you would see clear pattern; antioxidant reserve dropping and TAN slowly climbing. It is not advisable to continue to use oil which antioxidant's reserve depleted more than 80% from its original value, because at any point after that, TAN number would start rising more rapidly.
With automotive lubricants, TBN depreciation is the parameter to check and track, and replace the oil when before it approaches zero. Consequently, you are not supposed to see TAN number in those oils, as acid would start being very active (corroding) at those high operating temperatures