Relationship Between Oil Leaks and Contamination

FIRST - NOT AN EXPERT
ANY FLUID LEAKS REQUIRE THE ADDITION OF MAKE UP OIL. NEW OIL IS DIRTY - EVEN IF FILTERED THE ADDITION OF NEW OIL MAY REQUIRE THE RESERVOIR TO BE OPENED - SUBJECT TO MORE CONTAMINATION. DIRT PARTICLES CAN SCORE CYLINDER RODS, VALVE SPOOLS, CAUSE EXCESSIVE WEAR TO PUMPING COMPONENTS, RELIEF VALVES TO STICK ETC. THEREBY
INCREASING CONTAMINATION, POWER CONSUMPTION AND POSSIBLY CREATING NEW LEAKAGE PATHS. KEEPING YOUR OIL CLEAN TO A SET ISO STANDARD AND TRYING TO CONTINUALLY IMPROVE ON THAT STANDARD WILL REDUCE LEAKAGE, REDUCE COMPONENT WEAR, REDUCE OIL CONSUMPTION, REDUCE FILTRATION COSTS (NOT INITIALLY), AND MOST IMPORTANLY REDUCED DOWNTIME AND INCREASED PROFITS. (MANAGEMENT INITIALLY UN-HAPPY SOON TAKING CREDIT FOR THE SAVINGS)

Just from experience when relating to Hydraulic oils and contamination
Three major points
contamination may be classified as
solids/liqids or gases
internal or externals
leaks may be internal or external internal leaks are more dengarous than external as they increase oil temperature significantly.
Now coming to relation between contamination and leaks following can be added
If its a liquid contimnation bringing down the viscosity internal leaks will increase between clearance of hydraulic mebers.
solid contaminations also increase clearnces and wear outs and hence increase internal leaks
Internal leaks in turn increase oil temperature effecting seals to harden and leak reduces oil life by oxidation and forms acidic products which attacks hydraulic members/actuators.
The oxidation rate is ctalysed by presence of water as liquid contaminents and solida like iron and copper.
SO THE RELATION IS NOT ONLY DIRECT but may be geometic progression.
The failure of hydralic system is contributrd to contamination(90%) and leaks are just one of them hopefully I could contribute .

Arupanjan Mukherji

The extreem hot and cold cycling of your hydraulic system will cause the seals to at first leak allowing ingress of contaminents which further degrade the system leading to failure. A quality water/glycol hydraulic has cooling properties sufficient to prevent the high heat and in addition the Viscosity does not change through the temperature range. The drawback in the past has been lack of lubricity in the fluid. There are more than a couple available on the market now.

I know its not much of a problem in cold countries but in hot and dry climate water glycol is difficult to maintain as water evaporates and viscosity changes and has no been successful in tropical countries. Also question of compatibility and quality of water being added.
I know of a company who sell more water than the fluid to maintain water glycol.
Any comments on this
regards
Arupanjan

Rolly,

I must agree with Arupanjan, leak and contamination are directly linked. We have several large press hydraulic systems. The systems that are closed up tight show very little signs of contamination. Those with leaks require extra care and attention to maintain. Remember, if oil can get out, contamination can get in. As far as cooling, we have three 5000 gallon reservoirs. They operate on both three different types of oil. We maintain the operating temperatures with the use of heat exchangers. While the change in temperature can cause problems, maintaining the temperature at a constant during running will minimize these problems. You can also use desiccant breathers which will minimize this effect. Just remember, the cleaner and more leak free your system, the longer life and more effeciently it will operate. Hope this helps.

Yap Marty
Nicely summarised. Maitain the fluid cleanliness and Temperature - no problem
Get into oil analysis for filter effectiveness
100% reliability
regards
Arupanjan

Rolly,

One thing that we all forget is the seals and gaskets. Many of the rubberised seals age more due to the ozone in the environment than anything else. This will result in hardening, cracking and brittleness which in turn will permit ingress of air, water, dirt and other contamination prevailing in the environment at that location. On the other side, it will allow fluids to leak out.

Hussam Adeni

Misalignment,unbalance of seal-shaft interface
is also the factor for oil leaks.Heat is the
major culprit for seal deterioration,ofcourse
oil doesn't have adequate lubricity to protect
seals.Deformation of seals due to lack of strength causes oil leaks,eventual contamination
ingression.

Bala.

First of all we are trying to find solutions to a problem of heating up of hydraulic system which may or may not be related to leakages ( internal)

Today systems are sized smaller allowing no room for ventilation and thus reducing the retention time of the fluid in the system.Increased pressures could also take the toll on seals. Therefore better seal chemistry should be adopted along with contamination prevention measures.

I would suggest better design of hydraulic power packs with good return line filtration in order to ease this problem.

There has been a very lively discussion till now on this topic, almost all the contributors agreeing on the point that leakages are the results of keeping the oil contaminated,more leakages mean more contamination in the oil.
Due to contamination, the oxidation of oil is accelerated and these oxidation products combine with moisture to form acid which affect the seals adversaly. Of course excessive heating of the seals is another reason which can be also related to contaminants.
So it is advisable to keep the oil superclean and free from moisture by installing some purifying system.But it has been observed that most of the users do not keep the oil tankclean, you may find a thick layer of mud at the bottom of the tank, sometimes they get their oil cleaned, sometimes they change the oil, but nothing is done to remove that layer. Some of them neglect to keep the breather caps tight at its place, some others keep the tank top cover itself open. All this leads to heavy quantity of contamination entering into the tank.They first need some education of keeping the tank closed at every point and to get it cleaned thoroughly after certain periods, specially the mud layer at the bottom. I agree that contaminants increase the leakage in geometric progression.All the oil seals and gaskets have limited life, so they must be changed periodically to reduce leakage, Yes, the contaminants reduce their life drastically and they need premature changing.

I agree with you that system integrety is a key to keeping your oil clean and reducing leakage. You didn't mention that the contaminants also act as an abrasive to cut away the tolerances around the seals contributing to rapid failure and leakage. As far as the mud in the bottom of the tank if an aggressive approach is taken from the outset and the system is never allowed to get that dirty then the sludge should not accumulate to that degree. Periodic inspections of the interior of the tank should be conducted at each oil change and if necessary the tank should be cleaned of any sludge that has accumulated. However, most of the time the sludge on the tank bottom is there to stay and will not have much of an effect once a poorly maintained system has been cleaned up. If you are able to maintain your target cleanliness levels then intrusive cleaning methods may cause more problems as far as stirring up the past so to speak.

Excellent responses and comments in this forum. The only addition that I wanted to make is that there have been some recent studies and STLE publications demonstrating that polymerized oil oxidation products will accelerate seal deterioration and may lower seal elasticity. This means that oxidized oil will shorten seal life, increase hydraulic oil leakage and indirectly cause a host of other problems. Please contact me for more information on these studies.