Priority Divider Valve Question

[audoguy]

Hi All,

I am planning to add a lift to my log splitter. Of course, it will go way too fast if I just send the 11GPM from the pump to it. My splitter (ram) valve also does not have a power beyond....

I am considering running the pump output to a priority divider valve

3/4" NPT 30 GPM ADJ PRIORITY DIVIDER VALVE RD575

with the Excess Flow (EF) port going to my ram valve and the Priority Flow (PF) port going to my lift valve. The RAM valve has a pressure relief, but the lift valve does not. My question is, with the above configuration, will I damage (by dead heading) my pump when my log lift cylinder lift hits the stop or will the flow continue through the EF line and open center RAM valve? Should I be reversing the EF/CF configuration I described above so EF goes to the lift? I assumed EF was usually the larger flow and should run the ram...

There are some very ambiguous statements about how these priority dividers act when the CF or EF ports are plugged, thus my question about the set up.

Thanks for any guidance,

Audo

 

[mrmikey]

You have it plumbed right, you want to control the lift cylinder flow so you want to be able to set that to the lowest flow 3-4gpm. If you go the other way you have no control of the amount of oil going to the lift cylinder.
You will need another pr valve as the flow control valve works on flow not pressure, it'll try and keep the controlled flow at whatever you have set regardless of the pressure you build up.
If the area of the valve is going to be a bit crowded put a pr valve right off the pump and disable the pr on the splitter valve, that is if you want to use the same pressure on both cylinders.....Mike

 

[JCByrd24]

Agree I think you'll need relief on the lift. Most of those dividers have a statement that if flow is blocked to one port it reacts by blocking the other which would be bad. A relief on the pump protecting the whole system is a good idea.

 

[J_J]

Why do you need a 30 gal valve?

Have you considered this kind of valve?

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[audoguy]

Hi J. J.

I was hoping you would chime in. I see from other threads that you know Hydro's

I had not chosen the valve you suggest specifically because it says "Please note if during operation the controlled flow port is blocked the valve will compensate in such a way as to shut off flow to the excess port" This is exactly the opposite of what I was hoping for. The valve I selected did not have such a statement so I was hoping when the CF port was blocked it would just "relief" to the EF port (my open center RAM valve). From the comment above it seems my selection suffers from the same feature of shutting off EF when CF is blocked.

For the valve you suggest (which I really prefer) I have a couple of questions....

Does the relief work for both the CF and EF (so the control valve keeps directing additional pressure from inlet to CF, restricting EF, until the relief valve hits 1500 PSI then it dumps anything on either port above 1500PSI to tank?

Secondly, I don't see a "tank" connection on the valve. Am I missing it? Does it try to tank to CF or EF on pressure relief? The answer to this second question probably voids the first. Obviously if it uses CF or EF as tank on relief that output is not protected by pressure relief.

Thanks again!!!

Audo

 

[J_J]

Why does your log lift valve not have a relief valve.

Your log splitter valve has a relief, so you should never deadhead the ram valve. as the relief fluid will go to tank.

Every hyd circuit should have a relief valve.

You can make the log lift circuit slower by smaller hose, adjustable needle valve, fixed orifice/washer. etc

 

[oldnslo]

For the valve you suggest (which I really prefer) I have a couple of questions....

Does the relief work for both the CF and EF (so the control valve keeps directing additional pressure from inlet to CF, restricting EF, until the relief valve hits 1500 PSI then it dumps anything on either port above 1500PSI to tank?

Secondly, I don't see a "tank" connection on the valve. Am I missing it? Does it try to tank to CF or EF on pressure relief? The answer to this second question probably voids the first. Obviously if it uses CF or EF as tank on relief that output is not protected by pressure relief.

Thanks again!!!

Audo

Audo,
On the spec page for the valve that JJ suggested it states that valves with the built in relief MUST have the EF port connected directly to tank.

I believe most if not all priority flow control valves work where if the priority flow is blocked ALL of the flow is blocked.

As others have stated the relief valve should be the first valve in line from the pump to protect the pump from over pressure.