Very. not sure why it would be more useful than a power beyond circuit, though. Response time improvement maybe? Not to mention the fact that maintaining pressure builds heat and robs power...See how easy it is to gain knowledge . All it takes is an open mind, eyes, and ears. Plus you have the added ability to reason
BONUS TOPIC OF THE DAY - CCLS
There is a type of closed center control valve called Closed Center Load Sensing (CCLS) that can be used with a fixed displacement open center hydrauluc system. Ford was fond of it.
A special open center unloading valve is required. It is installed in the pump neutral (PB) circuit and it passes incoming pump flow through to tank just like a standard open center control valve. It also has two connections to the CCLS control valve.
One connection is called the load sense line and the unloading valve maintains a low (~200 PSI) standby pressure on it. The other connection is the pump pressure supply line which is normally kept at zero pressure
When the CCLS valve is in neutral the unloader valve is dumping (unloading) the fixed pump flow down stream to tank. When the CCLS control valve is actuated the pressure in the load sense line drops and that causes the spool in the unloader to automagically shift and divert pump flow to the inlet port on the CCLS valve and from there to the motor/cylinder being actuated. The CCLS valve returns exhaust oil from the actustor to tank via a separate tank return line just like a conventional closed center control valve.
When the CCLS control valve is returned to the neutral position pressure in the load sense line comes back up to standby pressure and automagically forces the unloader spool back to center, pump flow to the CCLS valve is shut off, and the pump unloads to tank again.
Clever ehh?
Adding Rear Hydraulics
- Thread starter bam43431
- Start date
TheOldHokie
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Equipment
L3901/LA525, B7200DT/B1630, G2160/RCK60, G2460/RCK60
When properly implemented it has the same advantages as other types of closed center systems.
Its the same principle and a little less efficient but also less expensive to build as is a closed system with a variable displscement pump. In a closed center system with a variable displacement pump the load sense line is used to change the angle of the pumps swash plate and vary output flow rate rather than divert a fixed flow.
I have not thoroughly investigated them but I think the closed center hydraulics on the larger Kubota M series machines still uses a fixed displacement pump.
Dan
TheOldHokie
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Equipment
L3901/LA525, B7200DT/B1630, G2160/RCK60, G2460/RCK60
Almost all large agricultural tractors use some variant of closed center operation. In the simplest form of closed center the unloading valve is nothing more than s pressure relief that maintains full pressure at all times. I think thats how the old JD closed center systems worked. Very inefficient and hard on the pump but with great hydraulic response. Modern closed center systems use various forms of load sensing and are often opaguely described as "pressure and flow compensating" (PFC).
If you ask Google you can get a lot of information, most of it inaccurate or flat out wrong.
Dan
You said a mouthful there.
I believe I have located what i need. the P40G-1A1 Summit spool valve and a power beyond adapter. About $100 total. I have a friend with a Gates hose machine, so I think i'm in business. Thanks for all your help.
TheOldHokie
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L3901/LA525, B7200DT/B1630, G2160/RCK60, G2460/RCK60
That will do it. I have the two spool version of that valve on my loader right now. Notice I used the two tank return ports as the tee.
Dan
That's a good setup. Most people don't realize that they lose the ability to control their flow if they go with the $1k+ 3rd function kits. I'm really surprised that Summit or WR Long doesn't sell a kit to do exactly what you did here.
TheOldHokie
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Equipment
L3901/LA525, B7200DT/B1630, G2160/RCK60, G2460/RCK60
Maybe too much competition
EZ-PZ Kubota Tractor Remotes
An affordable easy to install auxiliary valve kit customized to fit L01 and L02 series tractors. No hydraulic expertise required and kit can be installed in about 30 minutes.
windyridgefarm.us
Dan
Well I'll be damned. Good for you.Maybe too much competition
EZ-PZ Kubota Tractor Remotes
An affordable easy to install auxiliary valve kit customized to fit L01 and L02 series tractors. No hydraulic expertise required and kit can be installed in about 30 minutes.windyridgefarm.us
Dan