I need to be enlightened somewhat on water contamination for an industial lubrication system. This is in a rolling mill facility-we use EP 320. Several large gearboxes are on this system-low speed but heavy duty. Due to the design it is not possible to keep this water free. Sometimes it will seperate and you are able to drain off a large portion of the water but as often happens its mixes and we have2500-3000 gallon of oil water mix. What about the biological growth or is this a myth. Thanks for any input. Maytag This is a circulating system-dry sump gearboxes and large tank with low pressure /high volume pumps ,spray bars and metering orfices control the flow of oil to the various gears,bearings,screws,etc

Hi Wilson

I have also worked with rolling mills for a decade with dry sump gearboxes ,but I don't understand how the water enters the gear sump ? does it enter near the mill drive end or thro heat exchangers ? It will be better to attack the source rather than looking for solution.Does the gear sump have proper breathers? Looking forward to hear more details?

Desiccant breathers may help but filtering the oil sounds like the best bet for salvaging the 2500 gallons. Make sure though that it is a high viscosity cart designed for higher viscosity oils and that it has a water filter. Also make sure it has sample ports incorporated so you can sample and trend the success of the cart.

This is a large breakdown mill-it has a set of entry and exit manipulators(reversing mill-the manipulators move the bar to different positions in relation to the rolls. This is hot rolled and all water cooled-some of the drains for a rack and pinion drive are located where they can take in water,dirt etc. This has been an ongoing problem for 16 years and not much way to prevent all the water leaks-downtime is figured at $1100/min-nobody wants any unscheduled downtime. Maytag

Tom
Firstly, bacteria will grow in oil and can create many problems ranging from the obvious, particulate contamination through to causing demititis to people who may come in contact with the bacteria.
Probably your best bet for moisture removal would be to use a centrifuge depending on what limits you deem acceptable. They will, in general, remove all the free water and some of the emulsified water. They are also useful for removing particulate contamination down to a VERY nominal 10 micron range (depending on centrifuge type, naturally). If this doesn't provide enough moisture removal capacity then it is possible to link a vacuum dehydrator in line with the centrifuge to remove any disolved water in the oil.
If, as you say, it is going to be a long term problem then it is definately more cost effective then trying to run coalescing filters which generally are no more effective then centrifugal seperation anyway.
There is a rather large captial investment involved but considering what the down time will cost, it should be pretty easy to justify.
Regards
Michael

I agree with MC that a permanant means of removing water is required. This should be a standard item for "ALL" large circulating systems. Centrifuges are OK we used them on all Navy ships to remove water form the turbine and reduction gear lube systems. Centrifuges will remove free water and break up some loose emulsions and solids.

Vacuum dehydration seems to be the preferred method these days as they are effective in remove all types of water, but they are more expensive and require a little more general maintenance. A prefilter is used to remove solids.