Hydraulic oil temperature

[MacandTosh]

I'm at the phase where I'm figuring out the hose assembly for my application, and I think almost everything makes sense except for one part; Temperature.

The articles I've been reading state that when looking for the right hose, I'll have to consider the operating system temperature of the fluid and make sure the hoses are rated for that temperature. This implies I'll have to calculate the theoretical system temperature but they don't say anything else.

Can I just estimate this by looking at the pressure drops through my system or is there more to this?

 

[oldnslo]

Hydraulic systems should run below 180 degrees F in most cases. There are extremes where the hose may be exposed to higher temperatures like in an engine compartment of running next to an exhaust system. Other extreme would be cold weather if in the north country where -40 F or colder could be seen.

 

[Roadworthy]

You may be over thinking the whole thing. I just take an old hose into the local hydraulic shop and they make a new one. Unless you've got a special application generic hydraulic hoses should work. You may be able to find your hydraulic pressure in a shop manual for your tractor if you want to be really conservative.

 

[Rich B1]

What are you building?

What is the duty cycle?

The old rule of thumb is 100 deg. over ambient for a high duty cycle system. Low duty cycle will be lower.

Got a feeling you will be fine with standard hose. I work with equipment used in steel mill melt shops. Bulk of the hoses are standard hose. Those subject to extreme heat are covered in stainless wrap to protect the hose.

 

[MacandTosh]

What are you building?

What is the duty cycle?

The old rule of thumb is 100 deg. over ambient for a high duty cycle system. Low duty cycle will be lower.

Got a feeling you will be fine with standard hose. I work with equipment used in steel mill melt shops. Bulk of the hoses are standard hose. Those subject to extreme heat are covered in stainless wrap to protect the hose.

I think I see. So what's normally done is that people normally spec their hoses based on pressure, flow rate, etc, and disregard the temperature of the fluid system unless it's something really special?

I guess my confusion stems from why would I read that 180 F is the max limit if you don't want the seals to break apart, when I see hoses designed for like 400 F?

 

[RickB]

I think I see. So what's normally done is that people normally spec their hoses based on pressure, flow rate, etc, and disregard the temperature of the fluid system unless it's something really special?

I guess my confusion stems from why would I read that 180 F is the max limit if you don't want the seals to break apart, when I see hoses designed for like 400 F?

I don't understand why that is a problem, concern or even a question. Clearly a 400 degree rated hose has adequate thermal tolerance for any mobile equipment application.