Oil Recirculation in closed loop system

[J_J]

Excerpt from Eaton steering valve like mine.

Flow is only directed to the tank port when steering is
operated. Avoid systems where return flow from tank
port is used for auxiliary functions.

Do you not have a tank port on your steering valve?

His oil was discolered for some other reason.

 

[SpringHollow]

If you push the left rod in, it goes to the return via the tee.

If the pump is doing the pushing, the flow from both cylinders goes to the tank via the return.

I wish I had that hydraulic modeling software to show the flows.

Ken

 

[MossRoad]

The majority is still getting transferred from cylinder to cylinder, and not much to the tank.

 

[MossRoad]

Moss,

If you trace the two vertical lines, one goes to the pump via the valve. The other goes to the tank via the valve.

In a hydraulic cylinder circuit, pressure determines the amount of force you can overcome and flow determines the speed and magnitude of movement. If there is no (or minute) flow to the tank or the return of the pump, then there is no real movement. You are saying no flow to the return of the pump/tank so there can only be minimal movement of the cylinders.

Flip the right cylinder 180ｰ leaving the hose connections as is. If you now mechanically connected those two cylinders as is to your FEL, it would work appropriately except because the rod end are switched, the cylinders would not have equal maximum force.

In this case, I am afraid that everything I know about physics as applied to hydraulics says you are not thinking about this correctly. Doesn't mean that I am not missing something because I am quite capable of having a brain fart but in this instance I do not think I am. If I thought there was an even 1% chance I was wrong on this, I would ask in the hydraulics forum.

Ken

Well, everyone in the choir is off-key, but me! :laughing:

 

[MossRoad]

If you push the left rod in, it goes to the return via the tee.

If the pump is doing the pushing, the flow from both cylinders goes to the tank via the return.

I wish I had that hydraulic modeling software to show the flows.

Ken

Me, too. A nice animated GIF would do me some good.

 

[J_J]

Or is the schematic this way, which would make more sense?
View attachment 423762

When you push more orange stuff in the cyl, where is the orange stuff on the other side of the piston going.

Answer: TANK

 

[SpringHollow]

In your diagram, that is the same as saying the white hoses are supplying pressure. If the flow did not return up the vertical leg of the Tee on the "red" lines, then you have the red (low pressure side of the right cylinder) being stronger than the pressure from the pump. There is no way for that to happen if the red is connected at all to the return of a pump directly or via the tank because that line is at minimal pressure. If the red line does not connect to the tank/pump return, then there is no flow from the pump which means the tractor is not doing any work.

Ken

 

[MossRoad]

If you push the left rod in, it goes to the return via the tee.

If you push the left rod in, the right rod extends.

Someone just get in their car, drive over here and slap me silly cause I ain't getting it!!! :laughing:

 

[J_J]

The majority is still getting transferred from cylinder to cylinder, and not much to the tank.

NOt true at all.

You are filling both cyl, period. Both are doing work.

 

[SpringHollow]

What you are saying is I believe correct when YOU are pushing on the end of the rod and the valve is closed because YOU are doing the work and not the pump. You are the mechanical force I was mentioning earlier. But when the pump is supplying pressure via the valve, then you are the force to be overcome. And I hate to hurt your ego but unless you have a very long lever and a good fixed fulcrum, the pump/cylinder is moving you.

Ken