Hydrogen Sulphide smell in Hydraulic oil

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I have recently serviced a hydraulic power pack that "cooked" itself with the system going over the main relief @ 3000psi for around 5-6 hours. I was interested in the state of the oil as a result of this fault. There was a very strong smell of hydrogen sulphide, or cooked sulphur, and I am keen to know what temperature the oil got too to do this. The oil was Mobil DTE 25.
Anybody have any idea?

2/15/102:34 PM

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brettl3Member

Hi- Im going to take a wild guess and say it was over 250 degrees. I also would imagine the system had varnish issues, especially when the oil gets that hot. We had a system once that you could deep fry a turkey in, it was that hot!.....There is a formula that when the temp is over 150 degrees, I believe,-for every one degree increase,(over 150)the oil degradation is ten fold. You will need to look it up, its amazing. Brett

2/16/106:08 AM

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nicbMember

quote:
Originally posted by brettl3:
Hi- Im going to take a wild guess and say it was over 250 degrees. I also would imagine the system had varnish issues, especially when the oil gets that hot. We had a system once that you could deep fry a turkey in, it was that hot!.....There is a formula that when the temp is over 150 degrees, I believe,-for every one degree increase,(over 150)the oil degradation is ten fold. You will need to look it up, its amazing. Brett

Thanks for the input Brett. Are we talking 150 F or 150 C?
I didn't notice any strong eveidence of varnishing but I will check that out again.

Just as another point of interest the conductive heat was such that the pressure gauge, sitting on the relief valve, calibration plate melted to such a degree that it held the needle in position at 3000psi.

2/16/1011:40 AM

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tomwilsonMember

I've seen another formula relating to temp and life of your oil.
For every 10 degree increase over 60 C the life of the hydraulic oil is cut by 50%. That theory may not hold water any long as a lot of improvements have been made with VI and other additives.
Tom

2/16/104:58 PM

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erictr6Level 2 - 51 to 100 posts

I'm interested to know if the system was cleaned after the unit was serviced. And if it was, how was it cleaned.

2/17/105:38 AM

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brettl3Member

Hi Nic, 150 F, sorry...should have included that....I am also curious to find out how you cleaned the varnish. The present day oils have VI and additives but the varnish problems have crept up in recent years and it seems no one knows why? Nowadays oil shear is a concern but if the system is kept up with, no problem. Let us know- Brett

2/17/107:01 AM

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nicbMember

Brett

Sorry it has taken so long to get back to the post.

When we stripped down the relief valve cartridge and the control valve surprisingly we did not find any indication of varnishing!? So unfortunately I can not help with your question.

The tank and component were cleaned only with an "Elf" brand parts wash which brought everything up to a satisfactory level. the system has been refilled and system is away again with no problems

4/22/102:09 PM

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