Series, Parallel, and Power Beyond?

[Iplayfarmer]

Here's the pic of the loader valve.

Also, I couldn't resist. I started up the tractor just to try and feather the valves. Low and behold it's true. If I hold them both just right, I can get the loader to lift and curl at the same time.

 

[dfkrug]

Here's the pic of the loader valve.

Also, I couldn't resist. I started up the tractor just to try and feather the valves. Low and behold it's true. If I hold them both just right, I can get the loader to lift and curl at the same time.

If you get good at lifting and curling the bkt at the same time, you
will be amazed at how much more efficient you will be loading up from
a pile of dirt, gravel, etc.

 

[patrick_g]

Hydraulic fluid like electricity flows in parallel circuits in inverse proportion to the resistance to flow.

A. Einstein said, "Everything should be made as simple as possible, but no simpler."

All too often things get oversimplified and instead of clarification you get obfuscation. To say that electricity or hydraulic flow follows the path of least resistance is in fact often an oversimplification. Parallel flow in electricity or hydraulics will be in inverse proportion to the resistance to flow in that branch.

If there is a tremendous difference in the resistance to flow in two branches then it SEEMS as if ALL the flow is in the less restricted branch but that is most assuredly NOT the case, especially easily seen if the restrictions are not so out of proportion to one another.

In an algebraic format: total resistance to flow when you have parallel branches is equal to the inverse of the sum of the inverses of the flow restrictions of the separate branches. If the flow resistance was the same in two parallel branches then 1/2 of the total flow would take each branch. It is absurd to think that reducing the restriction just a tad in one branch (making it the path of least resistance) would give the least restrictive branch ALL the flow.

If both branches had 2 units of restriction the total restrictioin of the parallel network would be 1 unit and flow would be equal in the two branches.

If one branch had 2 units of restriction and the other had 3 units then by the algebraic method mentioned above...

Total restriction would be equal to 1/(1/2 + 1/3)

which simplifies to 1/(5/6) which is 6/5 or 1.2 units of restriction.

Depending on his valving arrangement this might be similar to the empirical demonstration by IPLAYFARMER when he found that he could in fact curl and raise his FEL bucket at the same time.

As for an electrical example: Consider that in your house if electricity all followed the path of least resistance the largest current user would work and all the smaller loads like lamps, the TV and such would get no power AT ALL. Virtually all electrical loads in your house are in parallel with one another (at least on a leg by leg bassis for single phase 220VAC.)

Pat

 

[RonMar]

Here's the pic of the loader valve.

Also, I couldn't resist. I started up the tractor just to try and feather the valves. Low and behold it's true. If I hold them both just right, I can get the loader to lift and curl at the same time.

Well you have one of Rays loaders with a prince 5200 series monoblock valve and it is plummed wrong... Your outlet line on the right side of the valve as pictured is plummed into the return port and runs right along into the rest of the system(steering and 3PH?). That port is rated for no more than 500 PSI of back pressure. How do I know this? I had one exactly like it on my Jinma, and it was plummed like yours is with the return port feeding the rest of the system. If you start bouncing around a heavy impliment on the 3PH, or ripping out rootwads with a middlebuster, you will start applying full system pressure to that return line and the #213 "O" rings at the spool ends will let go and start dumping hydraulic fluid on your right boot.

My 3PH control valve safety was also set wrong and was relieving at naearly 3000 PSI which didn't help matters any(3PH lifted like mad though).

To plumb this properly, you need to get the PB sleeve for this valve. surplus center has them for around $12. Surplus Center Item Detail and install it where the large hex head plug is now, just to the rear of where the outlet line is now attached. Then move the outlet line that feeds the rest of the tractor hydraulics to this new high pressure rated PB port. Then add a new return line to the forward port and run it to a LP return("T"d in down stream from the power steering if so equiped) back to the reservoir.

If you don't lift real heavy impliments with the 3PH, and don't want to mess with the plumbing changes, the "O" rings will probably last quite a while. They are only about $0.15 each and they take about a half hour to change out all of them on a 2 spool valve when they go.

I changed from a 2 spool valve to a 3 spool a few months ago, but did not yet make this change. I expect to go thru a set of "O" rings when I get the 5' brushhog back on the 3PH this fall. If I have some time this winter I will be making mine right.

 

[patrick_g]

Ron, Why so vague? If you have a contribution to make, give it a go!

Just kidding! I want to congratulate you on a great post. It is posts like yours that reconfirm my faith in our "shared knowledge base."

Pat

 

[dfkrug]

This is the Prince RD5200 being installed on a JD955 left fender
(no room on the right). The power beyond sleeve is installed
under the large cap in the middle. Both were purchased from
Surplus Center, but I have purchased numerous Prince valves
from Prince Direct when they were operating. A very good
valve, if a little larger than needed for this application.

IPLAYFARMER: you don't need 400+KB-sized pix when you post.
Those of us who do not have broadband internet access would
require minutes to see these excessively-large pix. 50KB-150KB
is plenty big enough.

 

[RonMar]

This is the Prince RD5200 being installed on a JD955 left fender
(no room on the right). The power beyond sleeve is installed
under the large cap in the middle. Both were purchased from
Surplus Center, but I have purchased numerous Prince valves
from Prince Direct when they were operating. A very good
valve, if a little larger than needed for this application.

IPLAYFARMER: you don't need 400+KB-sized pix when you post.
Those of us who do not have broadband internet access would
require minutes to see these excessively-large pix. 50KB-150KB
is plenty big enough.

Yep, that is a good pic of where the PB sleeve should go. Here is a link to the prince spec sheet with one of those valves configured for PB. Just imagine the single spool valve in the diagram on the second page of the spec sheet is your 3PH control valve downstream of the loader valve.

http://www.princehyd.com/Portals/0/products/valves/RD5000InstS.pdf

 

[Iplayfarmer]

IPLAYFARMER: you don't need 400+KB-sized pix when you post.
Those of us who do not have broadband internet access would
require minutes to see these excessively-large pix. 50KB-150KB
is plenty big enough.

Sorry, I usually keep the camera set for VGA which is usually under 100KB. I guess my wife had been taking pics of kids and set the resolution higher. I'll make a habit of checking from now on. Thanks!

 

[Iplayfarmer]

Here's something interesting. I was playing around with the loader again last night and I noticed that I can curl the bucket up and lift at the same time pretty easily, but I can't curl down and lift without being real careful on the controls.

What's with that?

I think why I never noticed before is because I never curl up and lift. If I'm lifting, I'm curling down to dump. If I'm lowering, I'm curling up to scoop.

Also, Is there a retrofit joystick control that would work with the valve that I posted the picture of?

 

[dfkrug]

Here's something interesting. I was playing around with the loader again last night and I noticed that I can curl the bucket up and lift at the same time pretty easily, but I can't curl down and lift without being real careful on the controls.

What's with that?

Lifting the boom requires lots of pressure. Dumping the bkt very little or
negative pressure. That is an unusual combination of motions.

Also, in dumping the bkt, gravity will be your main force and sometimes
the hyd pump can not move the bkt cyl as fast as it wants to go. So,
some loader valves have a "regen" ckt in that valve to speed up the hyd
flow by using pump output and oil return from the other side of the cyl
to dump the bkt.