Power Beyond Flow and Pressure???

   / Power Beyond Flow and Pressure??? #1  

jgrreed

Platinum Member
Joined
Jun 3, 2008
Messages
787
Location
Regina, Saskatchewan
Tractor
JD 4720
Hi,

Does anyone know what the flow rate and pressure comes from a power beyond kit on a 4720 (or other 4x20). I can't seem to find the specs anywhere.

I'm thinking of rigging up (with the help of my welding/fabricating father-in-law) a set of high flow lines to the front of my machine to run a FEL mounted snowblower/posthole auger/broom etc.

Let me know any thoughts.

Thanks,

-Jer.
 
   / Power Beyond Flow and Pressure??? #2  
A properly sized power beyond connection on an open center system will provide the pump's GPM and the relief valve pressure (not simultaneously) less a small percentage for line loss. In essence, whatever is available at the SCV will be available as power beyond flow and pressure.
 
   / Power Beyond Flow and Pressure??? #3  
I believe that the Power Beyond circuit runs directly from the sump and back again - therefore, the flow bypasses the steering and SCV's.

That would mean that the GPM would be around 17 at the PB and not the 12 GPM provided at the SCV.

And 2500 psi.

AKfish
 
   / Power Beyond Flow and Pressure??? #4  
I believe that the Power Beyond circuit runs directly from the sump and back again - therefore, the flow bypasses the steering and SCV's.

That would mean that the GPM would be around 17 at the PB and not the 12 GPM provided at the SCV.

And 2500 psi.

AKfish

Perusing Deere's 4720 spec sheet reveals a total hydraulic flow of 17.1 gpm of which 5.1 gpm is for steering. The pump type is listed as "dual gear" which means either a dual section gear pump with dedicated pumping elements for (1) steering, and (2) everything else, or two separate pumps for the same purposes. The odds of any tractor manufacturer robbing steering flow for any other purpose is as close to zero as anything can be.
 
   / Power Beyond Flow and Pressure??? #5  
Hmm.. the pump is a dual-geared (2 impellers) with separate output flows of 5.1GPM for steering and 12GPM for FEL, rear SCV - etc. Total flow of 17.1GPM.

The system is an "open-center" circuit.. does that not mean that the output of both impellers flow in a loop through the sump for a total flow through the sump of 17.1GPM?

So, when I'm running my backhoe or my log-splitter from the PB circuit (typically not steering) the total flow available is 12GPM or 17.1GPM?

Thanks,

AKfish
 
   / Power Beyond Flow and Pressure??? #6  
So, when I'm running my backhoe or my log-splitter from the PB circuit (typically not steering) the total flow available is 12GPM or 17.1GPM?

You get 12GPM max flow for that setup. Whether PS is handled by
2 hyd pumps on the same shaft (as noted by RICKB), or a single pump
with flow divider (as a lot of other CUTs use), your PS circuit flow does
not add to your implement circuit flow.

At least JD and Kubota publish these flow rates in their brochures and
manuals. Kioti publishes only total flow for my tractor, and you have to
have the factory service manual to find out the 2 separate flow #s. :-(
 
   / Power Beyond Flow and Pressure??? #7  
Hmm.. the pump is a dual-geared (2 impellers) with separate output flows of 5.1GPM for steering and 12GPM for FEL, rear SCV - etc. Total flow of 17.1GPM.

The system is an "open-center" circuit.. does that not mean that the output of both impellers flow in a loop through the sump for a total flow through the sump of 17.1GPM?

So, when I'm running my backhoe or my log-splitter from the PB circuit (typically not steering) the total flow available is 12GPM or 17.1GPM?

Thanks,

AKfish

The 17.1 gpm figure is a marketing tool only. There isn't 17.1gpm of pressurized flow available at a single component on that tractor.

What you have is TWO open center circuits (two loops). The steering circuit, and the 3pt/SCV/PB circuit.
 
   / Power Beyond Flow and Pressure??? #8  
Hi,

Does anyone know what the flow rate and pressure comes from a power beyond kit on a 4720 (or other 4x20). I can't seem to find the specs anywhere.

I'm thinking of rigging up (with the help of my welding/fabricating father-in-law) a set of high flow lines to the front of my machine to run a FEL mounted snowblower/posthole auger/broom etc.

Let me know any thoughts.

Thanks,

-Jer.

Right HERE on the JD site

12 gpm at 2500 psi for implements.
 
   / Power Beyond Flow and Pressure??? #9  
The 17.1 gpm figure is a marketing tool only.

I said that to a JD saleman recently when demo-ing a 4720, and boy did
he get mad. After some bluster, all he could offer was flat denial. The truth
does hurt. Great tractor, but any prospect should do their own research.
 
   / Power Beyond Flow and Pressure???
  • Thread Starter
#10  
Wow, nice discussion.......!!

Thanks for the info guys. I've found Prince PTO pumps that will attach right up and provide what I think is more than enough flow and pressurre.

I'm gonna start a new thread with some other Q's.

Thanks again,

-Jer.
 
 
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