How high up do I need to mount the hyraulic fluid reservoir relative to the pump?

[Brooklyyyn]

I've read that the reservoir should be mounted above the level of the hydraulic pump in order to get the gravity assist and keep fluid flowing downstream constantly. Is there any height difference I should be targeting or is it sufficient for them to be only 1-2" higher? 

[Purple Bullet]

I’m not well versed in all but basic hydraulics, but it seems to me, in a closed system, what goes up must come down and vice versa. Fighting head pressure on the front end of the load or the back end of the load should be the same difference. In any case I suspect that head pressure will be a very small percentage of the load in either case.

I think the only concern would be keeping air out of the intake.

[Frosty]

Not in any properly designed hydraulic system. The pickup hose and screen leads directly from the bottom of the reservoir, through the filters to the pump. A pump will easily lift the oil a couple feet without help.

The idea of placing the tank above the pump is something someone who doesn't work with hydraulics "figures" out.

There are REAL hydraulics books available, most hydraulics shops make them available for a nominal price or free so people don't kill themselves trying to figure out how to make something that can be lethally dangerous on their own.

Frosty The Lucky.

[Brooklyyyn]

I appreciate the response, thank you 

Edited June 16, 2023 by Mod30
Remove excessive quote.

[Frosty]

You're welcome, I knew all those years keeping the soils drill working had to be good for more than a pay check. 

Frosty The Lucky.

[KenH]

On 6/12/2023 at 3:32 PM, Brooklyyyn said:

I've read that the reservoir should be mounted above the level of the hydraulic pump in order to get the gravity assist and keep fluid flowing downstream constantly. Is there any height difference I should be targeting or is it sufficient for them to be only 1-2" higher? 

On the Coal Iron 12 ton (really only a 9 ton due to use of 3" cylinder) the reservoir is mounted so the oil outlet is perhaps 1/2" below the center of the hydraulic pumps inlet connector.  This puts the oil level perhaps 6" to 8" above the pump inlet providing plenty of head for the pump.

[Goods]

I was surprised by any concerns over the position of the reservoir tank, so I brought it up with one who I would consider to be a hydraulics expert at work. He basically said the main reason for having the tank above the pump it to keep the pump primed for start up. No real system gains in n most cases. I then mentioned that over has the systems in our building have the tank below the pump and that I was confused by that. He responded that most if not all of those systems have a check valve to keep the hydraulic oil in the suction line. Basically, it all comes down to system design, but keeping the level of the tank above the pump entrance simplifies the system. Simple is good in my mind, less to go wrong. 

I like this guys, keep me learning!

Keep it fun,

David

[Frosty]

They've had check valves as long as I can remember having to mess with hydraulics, say 30-35 years ago. Heck I got charged with changing out pumps that didn't have check valves. That really brings back memories.

Frosty The Lucky.