Foaming problem in generator seal oil?

[sb3]

We have a generator seal oil system where the seal oil runs through a vacuum tank which in turn supplies suction to the seal oil pump. The tank has severe foaming problems if we attempt to increase the tank vacuum to normal operating levels. Water in the oil does not appear to be the problem but I am at a loss to explain this in another way.

Has anyone dealt with this before? What is the solution or the problem?

Thanks

 

[byrdj]

You might first look for air infiltration, like around the inspection door flange, tank drain valves, even supply check and isolation valves.

Lube oil additives (or lack off) may be the problem. I'm not very knowledgable, but there are anti-foaming additives you can add. If the oil has becomed contimainated with something could be a problem. I had an experance where a little desiel fuel in the oil caused a lot of foaming.

The ablity of oil to detain air is a function of temperature. If the supply from lube oil is cool, the tension will make more foam as the air comes out in the tank. I know a fresh tank takes several hours to become "treated". then the normal refresh does not cause as much foaming.

If the flow to the seals is excessive, then the refresh rate will be higher and cause more than normal foaming.

Operating with poorly treated seal oil will allow air to enter the generator's hydrogen and degrade purity. If there is moisture, retaining rings may be attached with corresion.

Good luck

 

[byrdj]

PS
even a little water can be a problem. If you look at the specific volume of water vaper, the expansion is in the thousands ( I can't recall the excat values). I had a poor vacumn incident (don't remember foaming though) that was due to water

 

[hacksaw]

hopefully you are not pulling vacuum on the pump suction, but that issue aside, it sound like you are getting excessive seal leakage. what you are seeing is the dis-engaging of the gas form the seal oil...