Hydraulicspneumatics 2220 Sample5
Hydraulicspneumatics 2220 Sample5
Hydraulicspneumatics 2220 Sample5
Hydraulicspneumatics 2220 Sample5
Hydraulicspneumatics 2220 Sample5

Why You Should KNOW Your Hydraulic Oil's 'A.N.'

June 15, 2015
A hydraulic oil's oxidative condition is determined by an absolute measure of its total acid concentration. When oxygen combines with hydrocarbon molecules a chain reaction occurs, which results in the formation of organic acids. These substances darken the oil, increase viscosity, reduce foaming resistance and air release, and form varnish and sludge. In other words, the oil becomes unserviceable.

There are generally two conditions which necessitate an oil change. One of these is oxidative degradation. And the only way to know if the oil's life has expired based on this condition is to do regular oil analysis.

A hydraulic oil's oxidative condition is determined by an absolute measure of its total acid concentration. When oxygen combines with hydrocarbon molecules a chain reaction occurs, which results in the formation of organic acids. These substances darken the oil, increase viscosity, reduce foaming resistance and air release, and form varnish and sludge. In other words, the oil becomes unserviceable.

The total acid number (AN) test result is expressed by the volume of the alkaline, potassium hydroxide (KOH) in milligrams (mg), required to neutralize the acidic components contained in one gram (gm) of used oil.

Due to their additive composition, new zinc-based, mineral hydraulic oils can have a rather high initial AN of 1 to 1.5 mg KOH/gm. This number initially decreases as additives deplete. But as the oil starts to age and oxidize, the formation of acidic by-products reverses this trend and causes AN to rise.

For mineral hydraulic oils, AN of 2.0 mg KOH/gm is the typical trigger value for an oil change. But for synthetic esters and some triglycerides (vegetable based oils) AN can be as high as 5.0 mg KOH/gm before an oil change is required.

With the above in mind here's your mission, should you chose to accept it:

  1. If you don't know the AN value which should trigger an oil change for each of the hydraulic oils you are using - contact your oil supplier to find out.

  2. If you don't know the current AN of the hydraulic oils you have in service, isn't it time you found out? This is one reason why failing to regular oil analysis can be a costly mistake. And to discover six other costly mistakes you want to be sure to avoid with your hydraulic equipment, get "Six Costly Mistakes Most Hydraulics Users Make... And How You Can Avoid Them!" available for FREE download here.
About the Author

Brendan Casey Blog | Author

Brendan Casey is a war-weary and battle-scarred veteran of the hydraulics industry. He's the author of The Hydraulic Troubleshooting Handbook, Insider Secrets to Hydraulics, Preventing Hydraulic Failures, The Definitive Guide to Hydraulic Troubleshooting, The Hydraulic Breakdown Prevention Blueprint and co-author of Hydraulics Made Easy and Advanced Hydraulic Control. And when he's not writing about hydraulics or teaching it, Brendan is flat-out helping consulting clients from a diverse range of industries solve their hydraulic problems. To contact him visit his company's Website:
www.HydraulicSupermarket.com

Continue Reading

Motor leakage variations

Oct. 18, 2006
affect low-speed performance

The Impacts of Electrification on Fluid Power Systems

May 15, 2023
Electrification presents challenges as well as opportunities to re-evaluate and improve upon the design of hydraulics and pneumatics.

Sponsored Recommendations

7 Key Considerations for Selecting a Medical Pump

Feb. 6, 2024
Newcomers to medical device design may think pressure and flow rate are sufficient parameters whenselecting a pump. While this may be true in some industrial applications, medical...

How Variable Volume Pumps Work

Feb. 6, 2024
Variable volume pumps, also known as precision dispense pumps, are a positive displacement pump that operates by retracting a piston to aspirate a fluid and then extending the...

What is a Check Valve and How Does it Work?

Feb. 6, 2024
Acheck valve, a non-return or one-way valve, is a mechanical device that allows a gas or liquid to flow freely in one direction while preventing reverse flow in the opposite ...

The Difference Between Calibrated Orifices and Holes

Feb. 6, 2024
Engineers tasked with managing fluid flow talk about both holes and calibrated orifices, but they are two distinct entities. A hole can be any opening, but a calibrated orifice...