Dual Tilt Cylinder Valves not Synced

[AKKAMAAN]

In a Closed Center system, valves are supplied from pump in parallel system. That will allow all valves to be simultaneously operated, since the pressure is constant, and flow will vary on demand. This will also allow extra valves to easily be plumbed in via a "T".

In an Open Center system, valves needs to be plumbed in a series, so each valve can restrict flow to create pressure. In addition to that each valve need to be plumbed in parallel, to allow simultaneous operation. This parallel core will connect pump flow to work port when spool is directed. So this is a SERIE-PARALLEL connected set of valves.

If valves are only SERIE connected, only valve at the time can direct flow. This system have an advantage when neither of the actuators are allowed simultaneous operation.

Here is a quote from http://www.engineersedge.com



"Basic Hydraulic Open Center Series / Parallel Connection System Schematic


Illustrated below, shows a variation on the series-connected type. Oil from the pump is routed through the control valves in series, as well as in parallel. The valves are sometimes stacked to allow for extra passages. In neutral, a liquid passes through the valves in series, as the arrows indicate. However, when any valve is operating, the return is closed and the oil is available to all the valves through the parallel connection. When two or more valves are operated at once, the cylinder that needs the least pressure will operate first, then the cylinder with the next least, and so on. This ability to operate two or more valves simultaneously is an advantage over the series connection."

 

[gpick]

The Engineer's Edge looks like a good resource. Thanks.

I understand the term open center now. Still not sure what I have, but think I am getting closer. I understand the basic principle of the plumbing and why two open center valves would not work equally. That said, I still don't know why mine are equal raising the links and not equal when lowering. The loads are equal in both directions, except when lowering the upper cylinder chamber does not have to PUSH the piston down since there is 1000 lbs of box pushing the oil out of the lower chamber. I still have a puzzle here, since as I mentioned the tilt cylinders do not lower when the tractor is not running. They gradually settle but not in direct valve control like the FEL does.

Since I have 3 hoses coming into the block, am I correct in assuming that one is the return and the other two are the series and parallel supply hoses?

As to why my FEL works differently, I realize that is because it IS different. A separate pump drives the FEL on the 545D.

Hydraulics are pretty sophisticated. Who knew! Thanks to those who are taking me to school on this.

 

[dcyrilc]

The Engineer's Edge looks like a good resource. Thanks.

I understand the term open center now. Still not sure what I have, but think I am getting closer. I understand the basic principle of the plumbing and why two open center valves would not work equally. That said, I still don't know why mine are equal raising the links and not equal when lowering. The loads are equal in both directions, except when lowering the upper cylinder chamber does not have to PUSH the piston down since there is 1000 lbs of box pushing the oil out of the lower chamber. I still have a puzzle here, since as I mentioned the tilt cylinders do not lower when the tractor is not running. They gradually settle but not in direct valve control like the FEL does.

Since I have 3 hoses coming into the block, am I correct in assuming that one is the return and the other two are the series and parallel supply hoses?

As to why my FEL works differently, I realize that is because it IS different. A separate pump drives the FEL on the 545D.

Hydraulics are pretty sophisticated. Who knew! Thanks to those who are taking me to school on this.

I'm guessing your system is Open Center because of the three hoses. On a properly plumbed Open center system you will have one supply hose from the pump, one hose for Power Beyond (usually to run the 3 Point Hitch [3PH]), and a Return to Tank hose. Some systems plumb the Return hose into the Power Beyond which is often considered to be incorrect plumbing.

Mind you, this is just a guess based on the plumbing. There could be other systems which use three hoses which I am unaware of.