one more hydraulic question

[bmw63]

one more question, as I prepare to add an additional valve to my tractor. am I correct in assuming it is ok for the valve to have a higher gpm, than the tractor system, i.e. it will still work,and not restrict anything, and the relief pressure should be the same as existing system ?
thanks,brent

 

[RonMar]

That should be fine as long as it is not a gross missmatch(6GPM pump and 200GPM valve). The only place this would be an issue I think would be with the safety. 2000PSI is 2000 PSI, so the safety will open at the correct pressure, the problem on a really large valve is that when the safety cracks open, it is expecting to flow large GPM. It will quickly flow the small GPM from the small pump, drop pressure and slam shut, pressure will build and the valve will burp again. This rappidly pulsing pressure felt back to the pump can be hard on things. A large valve spool is also built to flow a large ammount of fluid to/from the work ports so if too large a valve is used, valve operation may be very sensitive. If the difference is only a few GPM, it should work OK. For instance, My 20+ GPM loader valve on my 5GPM tractor pump works just fine.

 

[bmw63]

ronmar, I was going to use a valve that is 11 gpm, on my 5gpm tractor, however I spied a 5gpm valve that is a little more space saving I think will be a better choice. thank you for your response.
brent

 

[gotrocks]

Kub B-2910 book states pump 6.4 GPM , max pressure 1920 - 1992 psi

Would a valve listed at 5 GPM 2500 psi be Ok?

If not would a valve rated at 25 GPM be satisfactory for T&T addition?

 

[MJPetersen]

Gotrocks, The 5gpm valve would work, but you are in effect closing your system down to the 5 gpm level. Since everything is in series the worst restriction determines the flow for the entire system. Your valve in this case will flow less than the pump will produce (at rated RPM) and therefore will restrict the flow to other hyd events like the 3pt.

I personally do not think that a 25 gpm valve belongs on a 6.4 gpm tractor. It would work mind you, but as explained before not as it should. For a T&T it would be too sensitive and big and cumbersome. Normally they run 1/4 inch lines on a T&T to slow down the sensitivity anyway. You would be better off finding a 8-10 gpm valve.

Mike

 

[gotrocks]

Thanks Mike,
I plan on using an optional cap to hook hyd. lines up and will not be changing any connectons to 3 pt. or FEL.

The addition will only be for Top & Tilt.
Does this make any difference in your reply?

Thanks again,
Norris

 

[MJPetersen]

You going to use a pto pump? What is its gpm rating? Why a pto pump for only T&T? You have plenty of flow for T&T without aux pump and it would be a WHOLE lot more usable hooked into your tractors hyd.

More ?? than answers huh?

Mike

 

[gotrocks]

As you can tell I'm not "hydraulically educated".

I should have stated a 2 spool valve in the beginning.

Not planing to using a PTO pump,
plan to "tap" into the tractor auxiliary hydraulics.

Kub B 2910 has a mid and rear outlet.
The diagram shows "A" to implement inlet max. flow 6.4 U.S. gal/min
"B" from implement outlet
I understand implement to mean the control valve, then the other 4 hoses would connect to the two double acting cylinders and the each valve would activate the individual cylinders one for each valve.

Am I getting close?

 

[RonMar]

Where does that port "B" go to? IF "B" goes back to the resovoir, then you may have a workable plan. However, most small tractor hydraulics do not "TAP" into the hydraulic system, they install control valves in series into a hydraulic stream. These valves are open center so the flow passes thru the valve unimpeded untill a lever is moved and work is being performend.

"Tapping" into a system usually implies the use of a diverter or flow sensing valve. Imagine a 3 port metal block. The flow is normally in on port 1 and out on port 2. Port 3 feeds the tap. When flow is detected leaving on port 3, the fluid is diverted to port 3 denying flow to port 2. This allows pressure to be built(need pressure to perform work) on whatever port is flowing fluid and one port will have priority over another. IF your system works like this, you may need a closed center valve for your added accessory. If you add a open center valve, the diverter will always sense flow to that port thru the opencenter valve and deny fluid to any devices downstream on the diverters other path.

It might be good if you could scan and post the diagram of your system so our answers can be on the same page as your plans.

 

[gotrocks]

Thanks Mike and Pat,
On another thread Bird had given a lot of helpfull advice, then I jumped on this one. Bird told me about the rear outlet on my B 2910 and said I need "open center valves".

I jumped in here because I had read somewhere else about heat build up and was concerned about my pump 6.4 gal/min and a valve I was looking at that was rated 5 gal/min.

Since everyone on this site is so pleasant and helpfull let me keep this going with a scan of my Kub manual and a drawing of what I thought would work for me.

After checking the two pics please tell me if I'm on the right track or all wet.

 

[MJPetersen]

Good Job on the scan and drawing. You are on the right track. Bird is right in that you do need an open center valve. it should be at or greater than your max gpm.

Think of those hyd blocks for aux hyd as detours. With the cover on the oil goes straight on its path (maybe a slight jog through the cover, but not much), but with the cover off and lines hooked up to the block the oil makes a detour to a valve, through the valve (power beyond port) and back to the other side of the block on its way to power the next thing in the line. You connect the line in and the PB circuits of your new valves to the blocks.

However, in your drawing, you are missing one very important line, the return to the tank. It is mentioned at the bottom of the picture from your manual. On your valve there must be a PB port (flows pressurized oil in the series) a return to tank (oil returning from the cylinders ) and a pressure line. Plus there will be 2 lines for every spool that you have in your valve assembly.

The above is what is necessary for the mid mount. It seems that the rear aux hyd is after the 3pt and therefore does not need the PB port as it just returns to the tank. Therefore your diagram will work, unless the valve has a relief then you need to attach the line to the tank return as stated in your manual.

Boy I hope that all made sense.

I was correct in my first post and my opinion holds

Mike

 

[gotrocks]

I plan to use the rear outlet so it seems I'm getting close to ordering parts.

But Mike, back to your earlier answer regarding the 5 gal/min vs 25 gal/min.
I have not had any luck finding an open center 2 spool at 8-10 gal/min.

Can you direct me to a possible source?

Or since you now know my plan do you think this valve would be servicable?

see pic.

 

[RonMar]

See, a pic is worth a thousand words. Open center valves are the order as you are installing them in series with the system flow. As mentioned if you are using the mid block, you will need a power beyond configured valve and that 7th hose for the return line(High pressure in, High pressure PB out, low pressure return out and 4 working lines, 2 per cylinder). A 6 hose non-PB valve should work on the rear block just fine.

I think you would be fine with a 20-25GPM valve on your rated 6+ GPM flow. I use a 25 GPM Prince 5300 series for my loader and grapple and it works fine on my 5+ GPM system flow(it is also all plumed with 1/4" line). As long as it is not a gross missmatch I think you will find it OK. If you find it too sensitive, you can always add restricted orfice washers at the working port connections to control the speed of the fluid flow.

 

[JerryG]

If I was plumbing a system like yours, I would order one of these two valves. The joystick is really nice to use with TnT, using the front to back for the top link and the right to left for the tilt. That is the way that I have mine on this tractor.
Surplus Center Item Detail
Surplus Center Item Detail

 

[kennyd]

Those joy-stick's certainly are nice...You can also get the Prince SV sectional valve, you can add one spool now, then add another next week if yo want! You can also mix-n-match different spool type if you want. They are rated for maximum flow of 16GPM, nominal 12GPM

PRINCE SV

 

[MJPetersen]

There you go--you got all the answers while I slept. You will find the lower flow valves much smaller, lighter, and, all things being equal, generally a little less expensive. All the valves suggested have an adjustable relief therefore you will need to run the return into the trany like in the bottom picture of your manual page.

Have fun and let us know how it goes.

Mike

 

[RonMar]

All the valves suggested have an adjustable relief therefore you will need to run the return into the trany like in the bottom picture of your manual page. Mike

Not necessarilly. It depends on how the valve is configured. If it is a valve setup for power beyond, it will have 1 high pressure inlet, 1 high pressure outlet and 1 low pressure outlet/return line.

A non PB valve will have one high pressure inlet and only one outlet line which is the combined High Pressure gallery and the return gallery. Since it is after the spool valves, this port will never see high pressure unless you restrict the outlet line in some fashion.

On those links to Surplus center valves, you will see accesories such as a power beyond sleeve and a closed center plug listed to the right. The PB sleeve replaces a plain plug in the side of the valve and adds an additional outlet point. The sleeve forces the gallery behind the plug to only exit thru the PB sleeve separating the high pressure and low pressure outlets.

Most all those valves at surplus center are open center, non power beyond so they usually show you the links to those optional plugs on the right.

If you wind up with a PB valve, since it is the last valve in the system, you can just "T" the two outlet ports together.

 

[gotrocks]

Keep um coming. I have read and re-read but I'm still confused.

If I could build this setup with 2x4s and a hammer I would not be such a bother. I would have had it working months ago.

RonMar, please look at the attached pic and "rub my nose in it"
to see if I can understand.

Since the valve states the PBeyond is optional are you saying I should be able to make things work with 6 hoses?

And not have to run back to the trany??? As Mike mentioned.

Once again I want to thank everyone that is responding to my confusion.
Please keep it coming, I still have not purchased any parts yet and it will be a while before I do.

We are going to my wife's sister's 80th birth day and at the same time her oldest niece who is 60. Let's see if I can still think clearly is that 140 years?

 

[MJPetersen]

Not necessarilly. It depends on how the valve is configured. If it is a valve setup for power beyond, it will have 1 high pressure inlet, 1 high pressure outlet and 1 low pressure outlet/return line.

A non PB valve will have one high pressure inlet and only one outlet line which is the combined High Pressure gallery and the return gallery. Since it is after the spool valves, this port will never see high pressure unless you restrict the outlet line in some fashion.

RonMar, in theory you are correct. I was merely emphasizing exactly what the manual says; "if the implement control valve has a relief valve, the tank port flow from the implement should be connected to the port located on the right hand side of transmission case." It does not specify if it is a PB or non-PB just the aspect of relief valve and it is specifically applicable to the rear aux port (as it is repeated for the mid port). That is why I stated that all the valves that were listed needed a return that "should be connected to the port on the tranny."

Gotrocks, the valve that you pictured has a PB port and a relief valve. Therefore, according to your manual, you should connect the inlet of the valve to the "A" port on the block, The PB to the "B" port of the aux block and the outlet to the tranny on the right side. You are right that the 4 green ports are the work ports.

I am looking forward to news of how it all works.

Mike

 

[RonMar]

Keep um coming. I have read and re-read but I'm still confused.

If I could build this setup with 2x4s and a hammer I would not be such a bother. I would have had it working months ago.

RonMar, please look at the attached pic and "rub my nose in it"
to see if I can understand.

Since the valve states the PBeyond is optional are you saying I should be able to make things work with 6 hoses?

And not have to run back to the trany??? As Mike mentioned.

Once again I want to thank everyone that is responding to my confusion.
Please keep it coming, I still have not purchased any parts yet and it will be a while before I do.

We are going to my wife's sister's 80th birth day and at the same time her oldest niece who is 60. Let's see if I can still think clearly is that 140 years?

Yes, if that is the last valve in the system, that valve will work with 6 hoses and NO PB sleeve/plug as your colored spots/arrows indicate. The drawing shows the power beyond plug/sleeve in place. If you had a side view of the valve, you would see a threaded port in that power beyond plug. The outlet port on the top of the valve(your blue arrow) comes from the return galleries from the work ports and the pressure relief gallery from the safety valve. It also connects to the main inlet gallery below it where that PB sleeve is shown. With a PB sleeve installed as pictured, the walls of the sleeve cover this last passage between high pressure port and outlet port and forces the HP line to exit thru the PB sleeve. The valve without a PB sleeve will have a low profile pipe plug(maybe 1/2" tall hex head) where the drawing shows the PB sleeve now.