Need hydraulic advice

[Tig]

I am adding rear remotes and top & tilt to my B7100. I have been reading the remote and top & tilt threads for months.
I have also been watching the Princess Auto sale flyer all winter and have picked up a cylinder for my toplink and a pair of DPOCVs.
With sping on my doorstep it's time to build. The first reality I face is that my tractor is small. There is not a lot of room to mount all this stuff. I have my eye on a small 2 spool valve. It is open center but does not have power beyond. Can I use this if it is the last valve in the circuit, or is power beyond a must in all circumstances?
Maybe the question I should be asking is, why is an unused power beyond port returned to the pressure block instead of just being plugged?
Thanks.

 

[MadReferee]

I am adding rear remotes and top & tilt to my B7100. I have been reading the remote and top & tilt threads for months.
I have also been watching the Princess Auto sale flyer all winter and have picked up a cylinder for my toplink and a pair of DPOCVs.
With sping on my doorstep it's time to build. The first reality I face is that my tractor is small. There is not a lot of room to mount all this stuff. I have my eye on a small 2 spool valve. It is open center but does not have power beyond. Can I use this if it is the last valve in the circuit, or is power beyond a must in all circumstances?
Maybe the question I should be asking is, why is an unused power beyond port returned to the pressure block instead of just being plugged?
Thanks.

Sure you can use the valve if it's the last valve in the circuit but isn't your 3pt the last valve? If you install a valve that is not configured for power beyond then all valves that are after it in the circuit cannot be operated efficiently, if at all, simultaneously with the valve before it. Valves not configured for power beyond dump the neutral pressure exhaust fluid from the work ports back into the main circuit instead of straight to the tank.

As to your last question, I guess I don't quite understand what you are asking. On a valve that is configured for power beyond, the neutral pressure exhaust fluid from the work ports is sent to the transmission tank/sump via the tank return outlet port. The other outlet port is the power beyond port. This port has a direct connection to the inlet port when all spools are in neutral and will allow any unused fluid to pass thru when a spool is not in neutral.

If the valve is configurable for PB, but not configured for PB then the PB sleeve is removed and the PB port and the tank port are effectively one and the same, so one is plugged.

 

[Tig]

Thanks Mad,
You are most likely right. The pressure block I refered to is called a hydraulic block in the manual. I figured that it was like a manifold. A line comes from the pump to the block and then from the block to the loader valve. The PB port of the loader valve goes back to this block and a solid line runs from the block to the TPH. If it's like you say the block must have two chambers. Looks like I'll have to go with a PB valve and then put it in the circuit between the loader valve and the hydraulic block. This is not going to be very tidy running lines back and forth past the hydro pedals.

 

[MadReferee]

The hydraulic block is simply a break in the main series pressure circuit with a connection for each end of the cut. The pressure side of the cut/block goes to the valve inlet. The other side of the cut/block connects to the power beyond outlet of the valve and eventually goes to the 3pt. This puts your new valve in series with the main circuit.

 

[Tig]

Thanks again Mad Referee. I guess I should follow that example and try to put a similar block in the line before it gets to the TPH. It would be the tidiest way to supply the rear remotes.
I'd like to mount the check valves to the cylinders and connect them via hardline. I'd also like to mount the quick disconnects to the same plate as the spool valve and connect them via hardline.
Which leads me to my next question. Are JIC 37* connectors the only option when working with hard lines?
Thanks.

 

[jimgerken]

Can't answer your question BUT I will add this: PLEASE do yourself a favor and add three hydraulic circuits, not two. If you do three, two are consumed by your TnT, leaving one more available for useage. If you add two, you will be looking to add another one soon. Plan ahead now. Thank me later.

 

[Tig]

Thanks Jim
I've read that in a few threads and I did think about it, but space is tight and I can't imagine what I would use the third remote for. I sort of talked myself out of it. The tractor will be used for snowblowing, box blading and road grading.
Now you've got me thinking again. What would I use the third remote for?

 

[Tig]

Ok, I've got my hard lines sorted out. In my head anyways. I found that my local supplier can make the lines for me. I'm going to use hard lines to mount the check vavles to the cylinders and also to connect the spool valve to the quick disconnects. I'm also going to use the hardline that now goes to the TPH to supply my spool valve and then run a line back to the TPH banjo fitting.
The B710 just over 1700 PSI and 3.1 gpm flow. I'd like to slow the cylinders down, way down. 1/3 gpm flow will give me about 5 seconds to extend my 4" side cylinder. In my limited knowledge of hydraulics I'm concerned about this will be almost a deadhead and could damage the pump during use. Can the relief valve be set low allow bypass and protect the pump? Or should any of this even be a concern?
If restricting is an option, is a needle valve the way to go? Surplus Center Item Detail
Thanks for your help.

 

[MadReferee]

Use 1/4" hoses from the valve work ports to the cylinders. That should give you enough restriction to be able to feather the cylinder movement. If it's not then go to a restrictor in the line. Usually 1/4" hoses does the trick.

I wouldn't worry about the pump deadheading because of minimal flow. However I would make sure that the pressure relief for the system and the valve (if it has one) arew set correctly based on whatever the maximum pressure is for your system. If the pressure setting on the relief is exceeded it will bypass, that's its job.

 

[tlbuser]

Thanks Jim
I can't imagine what I would use the third remote for. Now you've got me thinking again. What would I use the third remote for?

A dump trailer comes to mind