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hydraulicsman (Mechanical) (OP)
3 Jun 09 6:42
If you have 1000L tank filled with ISO32 mineral oil and create a boost presure by applying nitrogen directly to the oil @ 10bar max.
What negative effects might this have?
Using Ostwald Coefficient I get 100ml of Nitrogen will be dissolved per litre of oil @ 40C. However I believe it is proportional to pressure as well.
Can anyone offer any insight into the impact the dissolved Nitrogen will have on the oil and hydraulic components?
My feeling is it may be better with something seperating the nitrogen from the oil, as in all accumulators etc.
hydromech (Mechanical)
3 Jun 09 7:37
What makes you so sure that the oil will absorb the nitrogen in the first place, assuming that the tank will remain still and the surface of the oil is not disturbed too much.

There are such things as free contact accumlators where the oil is in direct contact with the gas. They are used on large forging presses to counter balance the falling load when the press is in prefill. Whilst I worked these types of systems, I never saw an issue or any need to recharge the gas cylinder.

I have seen loads of systems loaded with a gas of some sort and have never seen an issue with absorbed nitrogen or any other absorbed inert gas.


hydraulicsman (Mechanical) (OP)
3 Jun 09 7:49
Thanks for your reply.
Perhaps you're right, maybe there is no real need for seperation.
IceStationZebra (Mechanical)
3 Jun 09 20:42
I am not an oil specialist, but I don't think that nitrogen has any negative affects on oil. And I agree with Hydromech, if the oil is stagnant I don't see much mixing going on.

As far as entrained oil goes, it can cause damage to components, especially pumps. It also reduces the bulk modulus and causes the oil to be much more compressible.

flexibox (Mechanical)
16 Jun 09 7:52
consider a bladder accumulator to remove any doubt!
hydraulicsman (Mechanical) (OP)
16 Jun 09 8:47
I am afriad that is not possible. the design is complete and moving to assembly..

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