FEL control valve flow rate

[TimBuck2]

J_J, here is how my FEL is plumbed. Using existing fittings on the boom, I cold only tap into half of the curl circuit with a diverter valve (right or left) leaving the other half as part of the second function circuit.

The only place to do it would be up near the cab.

 

[J_J]

I know what I would do. I see several good places.

However it is not my tractor.

Maybe something like this.


http://www.tractorbynet.com/forums/...tl-loader-diverter-valve-fasse-finished-1-jpg

 

[TimBuck2]

The best I can tell from that picture, seems that the steel lines to the dipper cylinders were disconnected, and replaced with hoses to and from the diverter?

I think my plan will involved about he same or less new plumbing, and have the advantage of adding two remote circuits to the FEL rather than one. I think I will stick to my plan (if I ever find the time).

Thanks for your interest and advice.

Tim

 

[jasong123]

My concern would be that with a ca. 25 gpm valve, the entire 7.8 gpm would be "dumped" to the cylinder with just a small movement of the valve (I guess about 1/3 of the throw distance). So, it would be hard to control piston speed

However, I believe my loader valve is a variant of HUSCO 9210 (my tag fell off so can't be sure). Those have a max flow rate rating of 20GPM, so I probably would not feel the difference.

Leejohn, my loader valve joystick is built into the bracket that holds the valve. I think I could have a 3 spool valve made up that would work with the joystick (e.g., a BRAND TS model valve). However, looking this morning I see that I would have to cut away some of the bracket the supports the joystick so that the lever for the 3rd spool is accessible inside the cab. Alternatively, I would have to cut the whole top of the bracket off an use a valve with it's own joystick (similar to that suggested by JJ).

In the end, I don't want to cut up the loader just to reduce the hydraulic plumbing by a bit, so I am going to use a separate one spool valve for the third function.

Thanks for the input gents.

Tim

Tim,

it is actually the opposite away around, the flow down the open center of the valve is pinched off causing the system pressure to rise and overcome the load in your Workport (i.e. the load on your cylinders). With a small amount of flow going down the open center and a spool designed for a larger amount of flow you would have to stroke the spool further to generate enough pressure to overcome the load in the Workport. The HUSCO valve is rated for higher than the 8gpm but the spools are tuned to the lower flow rate.

Regards,
Jason

 

[TimBuck2]

Jason, you have given me something to thing about, but it is too late for me to finish my thinking tonight.

I am getting that when you operate the valve, you are pinching the open center flow. Are you saying that the work port is always open, and that you just build more preassure to lift the load by pinching the open center flow?

It seems to me that when pinching the open center flow, you also must be opening flow to the work port you want, otherwise, the added preassure would want to go to both work ports (extend and retract in the case of a double acting cylinder set-up).

 

[jasong123]

No, the WP are closed when the spool is in neutral but as you stroke the spool you close the open center, open the power Workport(WP) and open the other WP to tank. if you stroke the spool in the other direction the same happens to the center but the connection to power and the connection to tank are reversed. how all this happens, the timing and pressure gradient are the art of the hydraulic design engineer and can be the difference between a well tuned and nice feeling machine and something uncontrolable. HUSCO work closely with the OEM to make sure that the valves are tuned closely to the requirements of the machine.

Jason
(Director of AG Products - HUSCO)

 

[J_J]

My thinking is this, and to put it another way, a mismatch of the GPM flow of pump to valve will slow things down.

The open lands of the spool allow a certain amount of flow to go to the work ports, and the other part keeps flowing downstream.

What you have is two paths, work port and downstream.

To stop downstream flow, you have to fully stroke the spool, and then you shut off pump flow for any valve downstream for a short period.

No matter what the valves flow rate in GPM is, the full volume will only go to the work port when the lever is fully activated.

If you have a 25 GPM valve and your pump flow is say 8 GPM, then at half lever, I would say that 4 GPM would be going to the work port and 4 GPM going downstream.

You want the full 8 GPM to go to the work port, then fully stroke the spool and that will shut off the pump flow downstream.

If you had a flow meter, you could see the results of valve flow.

 

[TimBuck2]

Thanks J_J and Jason for your the interest. I have owned my old Ford for 24 years, but never really needed to think about hydraulics until I acquired my Kubota a year ago, and started envisioning what I can do with the extra hydraulics. I think I am learning slowly but surely, and folks on this forum are a big help.

Now Jason, if you could have gotten me that handful of parts to rebuild my float detent for something south of $134.95 (plus shipping and handling), that would have been really appreciated!