Hydraulic Oil
Hydraulic Oil
(OP)
Hey everyone!
I need help on hydraulic oil! I am very green - just out of school, and having a hard time finding out the right information on hydraulic fluid.
I have 3 fluids I am choosing from. I need to know the temperature range that these were designed for...
The thing is, everywhere I go, it seems to reiterate that what I REALLY need to know is the optimum viscosity my hydraulic system was designed for.. and from that I can look at my desired system operating temps and pick the grade from a chart.
Is this all correct? Any help would be greatly appreciated!!! Thanks!!!
I need help on hydraulic oil! I am very green - just out of school, and having a hard time finding out the right information on hydraulic fluid.
I have 3 fluids I am choosing from. I need to know the temperature range that these were designed for...
The thing is, everywhere I go, it seems to reiterate that what I REALLY need to know is the optimum viscosity my hydraulic system was designed for.. and from that I can look at my desired system operating temps and pick the grade from a chart.
Is this all correct? Any help would be greatly appreciated!!! Thanks!!!





RE: Hydraulic Oil
This holds true for many similar products.
You need to learn how to ask questions. Your post asked only one question. The answer to that is "no".
RE: Hydraulic Oil
RE: Hydraulic Oil
My supervisor tells me that all over the web there are operating ranges, and that that is how oil companies design their oil.
I can't get this information from the suppliers. I don't know who else to talk to, and my reference books aren't helpful either. they all say that i need to know the viscosity, and from that i see if the oils i have fall within that range.
so i have one question:
1) is synthetic oil designed/tested based on temperature range to see what temperature it can withstand before oxidation occurs?? because that is the "range" i need.
as i mentioned above, i have read technical data sheets, manufacturer's recommendations, msd sheets, and talked with several suppliers. i can't get the answer anywhere.
thanks.
RE: Hydraulic Oil
Regards,
Cory
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Hydraulic Oil
Maytag
RE: Hydraulic Oil
thanks maytag, i will go check the pump to see if i can get any info from that! appreciate your help!
RE: Hydraulic Oil
RE: Hydraulic Oil
Most gear pump manufacturers want <10inHg at start up and <5inHg during normal operation. So this takes into acount inlet piping, oil viscosity, inlet screen, lowest expected temp, ect. I think that piston pumps can't handle as much vacuum, but I'm not sure.
On the high end you risk excessive wear if the oil is too thin during "normal" operating temperatures. If the oil gets too hot oxidation gets out of hand, but of course that depends on what you want for a service period. I have never found solid data, but a rule of thumb is that oxidation doubles for every 10deg F. And most hydraulic seals and rubber components are designed for ~220 deg F. Above that you will start to get more cases of leakage, etc. Its a catch 22 where the suppliers keep supplying componts designed for 220F because the machines are designed for 220F max ..... because the components are designed for 220F.
ISO 32, 46, etc are fairly generic oils and can vary quite a bit, especially if you take shear-back into account. Synthetic oils will generally get you better viscosity at higher temps, the negative being cost. I have also used ATF as a cold temp oil. Tractor hydraulic oil is fairly crude.
As was mentioned before...it all comes down to viscosity. You need to find an oil that will satisfy both cold and hot temp conditions based on your system. Good luck.