BX25 Mid PTO Pump or BUST

[magicheater]

If you can get an rpm vs HP curve for your engine from Kubota [I know they have it], then we know how much HP is available from the engine at each point in the range. If we know the reduction ratio of the mid pto it tells us what rpm the pto turns at any chosen engine rpm. Blending these info streams will let us determine how much power is available from pto at every ptorpm. That and the pump table will enable us to see if 3 kpsi can be sustained somewhere in the rpm range with your engine and any given pump. It may be that we find your engine running 1750 rpm will turn that pump against a 3kpsi pressure. We know from the table it wont do it at the engine rpm corresponding to 2500pto speed.
larry

Is what you are saying that at a lower RPM of PTO/Engine speed more power may be available at that speed? Then at the max Engine/PTO RPM you would have max flow but not max pressure? Finding the sweet spot may be critical then as to what sort of implement may be able to be powered by this configuration, as many are flow oriented but power sensitive?

 

[Artisan]

Larry the following is from HERE

D902-ET02 is what the sticker on my engine says...FWIW

There are 2 performance curve graphs, one to 3600 RPM and one to 3200RPM.

I do not quite understand why unless there are 2 versions of the same engine.
I believe mine goes to 3200 RPM. I would suggest the 3200RPM graph is correct...

 

[Artisan]

...and I found the following HERE;

 

[SPYDERLK]

Is what you are saying that at a lower RPM of PTO/Engine speed more power may be available at that speed? Then at the max Engine/PTO RPM you would have max flow but not max pressure? Finding the sweet spot may be critical then as to what sort of implement may be able to be powered by this configuration, as many are flow oriented but power sensitive?

Very quick mind dump then bed for me. Possibilities exist for 3000psi even if you cant do it at the rpm corresponding to full eng power because required pump drive torque is constant at a given pressure regardless of the rpm you drive it, but engine torque is not constant. Peak engine torque is always below the rpm where max HP is made by the engine. As rpm drops below that the torque rises some to a very flat curve at a slightly higher level. This causes engine power to fall off less quickly than the HP demanded by the pump. Thus higher pressure will be available below the engines max rpm. We need the real figures to see what we might be able to squeeze out.
larry

 

[SPYDERLK]

Larry the following is from HERE

D902-ET02 is what the sticker on my engine says...FWIW

There are 2 performance curve graphs, one to 3600 RPM and one to 3200RPM.

I do not quite understand why unless there are 2 versions of the same engine.
I believe mine goes to 3200 RPM. I would suggest the 3200RPM graph is correct...

Those show the torque and HP. Its what we need on the engine. That is very good. What eng rpm is 2500pto? Talk tomorrow.
larry

 

[magicheater]

Very quick mind dump then bed for me. Possibilities exist for 3000psi even if you cant do it at the rpm corresponding to full eng power because required pump drive torque is constant at a given pressure regardless of the rpm you drive it, but engine torque is not constant. Peak engine torque is always below the rpm where max HP is made by the engine. As rpm drops below that the torque rises some to a very flat curve at a slightly higher level. This causes engine power to fall off less quickly than the HP demanded by the pump. Thus higher pressure will be available below the engines max rpm. We need the real figures to see what we might be able to squeeze out.
larry

So matching the torque output of the engine to the torque (resistance) of the pump is very critical to the success of the system?

 

[hddnis]

Actually, Im thinking you may may missed that his tractor is rated at 17PTOHP. All those implements are rated above that. Can those implements operate ok at 80% flow or is full rated speed a must? OP can pump around 9+gpm at close to 3kpsi.
BTW Bobcat vs Ditchwitch figures do not compare correctly. ... one or both are wrong.
larry

Nope, didn't miss that at all. His mid PTO HP in this case is a duty rating, but not the max limit of available power. A MMM will far exceed the 17HP rating a small percentage of the time. So when designing a system driven by the PTO it is acceptable to use max engine HP. Even more so when talking about implements that will be used while the tractor is stationary. I thought I had mentioned that a few posts back, but now that I look I see that I forgot that paragraph.:ashamed:

As to Bobcat and Ditchwitch figures, they are of course wrong as they are a Bobcat and a Ditchwitch. Brand preference aside, those are the published specs from the manufactures website. You can look for yourself...

Here:
Ditch Witch - Compact Utility Tractor, Mini Skid Steer - Compact Tool Carrier - Ditch Witch SK350

and here:
MT52 Mini Track Loader - Bobcat Company



Mr. HE

 

[Artisan]

Man I so can't wait for my connectivity problems to be resolved...

Larry the 2500 number is the mid PTO that I want to use.

The engine spins up to 3200 .

 

[J_J]

I have to ask if this is a temporary connect to mid PTO setup, or a permanent type setup?

Along with the pump, you will need a valve and reservoir, filter and hoses.

Will this setup be easy to remove?

You might consider just a plug and play pump setup, and only use it when you have a use for it.

You might be able to make this pump/valve setup in a kit form and sell it, or sell plans for same.

Something like this would increase my log splitting speed from my tractor, a Kubota B9200.

 

[Artisan]

I have to ask if this is a temporary connect to mid PTO setup, or a permanent type setup?

Along with the pump, you will need a valve and reservoir, filter and hoses.

Will this setup be easy to remove?

You might consider just a plug and play pump setup, and only use it when you have a use for it.

You might be able to make this pump/valve setup in a kit form and sell it, or sell plans for same.

Something like this would increase my log splitting speed from my tractor, a Kubota B9200.

J_J If a guy wanted to leave it on, he can leave it on, if he wants to pull it
off he can pull it off. I am not welding anything to frame, if I can help
it.

I have drawn a 10.25 gallon tank that should install in about 4 minutes
maybe less. It is looking really nice. The pump can be swapped in and out
if a guy pleases in prob about the same, add however long it takes to
connect hoses. If you spend a small fortune on QD's it might be fast,
and it is looking like I will need a small fortune to pull this off. One piece
at a time, indeed I pulled the trigger, were going to see something
happen, more later than sooner simply due to money. I shutter to guess
what a professional tank builder is going to charge me for a .25 thick
aluminum tank w/ baffles doubling as vertical stiffeners in case of belly-rub
and a 2" bung for a strainer and 3 maybe 1" bungs for filler, and two
returns. Brackets, bash edging, bracketry and gussets, then buy 10
gallons of oil, hoses, filter, valve(s) yes plural, flow control and I want
one valve foot controlled so all hands are free to deal w/ the tractor so
perhaps if you hang an auger off the front your hands are free to keep it
plumb. Did I mention buying prob a case of 3/4" QD's?

Again I now know enough to be dangerous, , but effective. I have been
drawing circuits and redrawing and really trying hard to come up w/ a
system that is SAFE and quick in and out. Yes, valves and pressure relief
and Power Beyond and Flow Control and Strainer and Filter on and on
are all on my mind, it is all doable. If I pull this off I honestly think I will
have a KILLER attachment, that will run a LOT of stuff. If I can cram
10 pounds of sugar into a 5 pound BX25 sugar container it should be a
breeze for anything larger.

There is no doubt in my mind that I will make unit ALPHA, and DELTA will
be thought about as APLHA is switched on for the first time. The
possibilities are endless.

As far as selling it or the plans, I have not thought about it. That might be tough, it is going to be
expensive. The owners of this board need to be taken into consideration
as well. Profits right off the top go to them, if sold thru here and there
may not be any meat left for a seller, unless it sells for high dollar. Of
coarse you will be the first person to get a set of plans if there ever are
any, gratis, as well as a couple others, J_J.

After I finish one system, and it is up and running and no bugs,
if you run into anyone in SO Calif that has a Kubota B9200 I can try to
get with them and design bracketry to fit. Thats another thing,
this concept will work w/ any Mid-PTO equipped tractor but each frame
is different, that means each pump hanger, drive shaft, tank bracketry,
placement of valves and hoses will all be different, weather it is a hi/lo
pump or other, no matter, each frame is different and I would need
each tractor at my disposal near my computer to fit to it.

My computer is prob going to be down for a few days...

 

[Iplayfarmer]

Dare I say Artisan is develping a belly mount post hole digger?

 

[SPYDERLK]

So matching the torque output of the engine to the torque (resistance) of the pump is very critical to the success of the system?

Yeah sorta. ... It will be sucessful period, but since we are pushing so close to [and marginally beyond] the limit of HP available, a little planning is important to put us on the hi side of the limper loper continuum.

... When you combine the need for pressure and flow capabilities required to assure operation of a wide selection of implements at their full rated torque and output speed it takes to the peak, and beyond, of what the BX25 can deliver. The ploy of lowering pressure to enable driving a larger pump will give full hydraulic implement speed - but speed that cannot be backed up by torque when needed. The implement motor will stop dead as soon as the system pressure set limit is exceeded. Its not like an engine which has a lot of energy stored in inertia. An engine system will supply the peak overtorque, and if brief youll hardly notice. If sustained, a significant overload [say 2x] will lug the engine to stall in a couple seconds. - time to react. Now we could use the large pump and set the pressure relief high enuf to lug the engine to stall. This would be almost as good as a straight engine hookup, but the quick acting of a hyd relief will always decouple quick torque peaks that caused above PR surges, but that the engine would have ridden right thru. When you are operating near the pressure peak of the system you get nuisance stalls with hydraulics. Preserving the option of cranking up the pressure temporarily makes it a lot more convenient.
...Ill look a bit at the graphs and say more when I reply to Artisan.
larry

 

[Skyco]

Dare I say Artisan is develping a belly mount post hole digger?

I'm guessing the mother of all roto rooters:laughing:


It was asked about ratios of PTO's-

According to my BX24 Workshop Manual, I believe the BX25 is the same--

Mid PTO=2500RPM at engine RPM of 3043 so ratio = .8215577 which equates to engine turns 1.2172 times for every one spin of the mid PTO shaft

and for reference

Rear PTO= 540RPM at engine RPM of 3142 so ratio = .1718651 which equates to engine turns 5.8185185 times for every spin of the rear PTO shaft


I find it interesting they geared them for rated PTO output RPM at different engine RPMs. Might be nothing to that other than it was easier to do it that way with the gears they had available.

I long ago made a P-Touch label for my dash to remind me exactly what engine RPM made 540 at the rear PTO.

 

[J_J]

The gearing on the mid PTO was designed for the MMM, to get the high rpm on the blade spindles, which is a finish cut.

 

[Skyco]

Understood. Just wonder why they didn't set them both up where rated RPM of both PTOs was at the same engine RPM.
That way those of us with CRS don't have to remember two set points for engine RPM.

PS I really wish the BX series had a big ole analog tach, with set points labeled, rather than the miniscule digital tach.
For some reason they gave us a huge fuel gauge instead...

 

[SPYDERLK]

Well......other than a deep hole in the ground... what's ya all think about a
prince # SP20B16***** Not for log splitting, a system a guy can plug "stuff" into and do a lil work. The BX25 only has I think 3GPM's or so at the
curl, looks like almost 10GPM's from this if I can pull it off. (I drew a tank,
it is sweet! Well...we will find out when I post a pic for the pros to criique' anywho)

I found a Hydraulic T-Post driver that pulls 5.3GPM that might be perfect
for such a system, I "think" .

D902-ET02 is what the sticker on my engine says...FWIW

There are 2 performance curve graphs, one to 3600 RPM and one to 3200RPM.

I do not quite understand why unless there are 2 versions of the same engine.
I believe mine goes to 3200 RPM. I would suggest the 3200RPM graph is correct...

Nope, didn't miss that at all. His mid PTO HP in this case is a duty rating, but not the max limit of available power. A MMM will far exceed the 17HP rating a small percentage of the time. So when designing a system driven by the PTO it is acceptable to use max engine HP. Even more so when talking about implements that will be used while the tractor is stationary. I thought I had mentioned that a few posts back, but now that I look I see that I forgot that paragraph.:ashamed:

I'm guessing the mother of all roto rooters:laughing:

It was asked about ratios of PTO's-

According to my BX24 Workshop Manual, I believe the BX25 is the same--

Mid PTO=2500RPM at engine RPM of 3043 so ratio = .8215577 which equates to engine turns 1.2172 times for every one spin of the mid PTO shaft

and for reference

Rear PTO= 540RPM at engine RPM of 3142 so ratio = .1718651 which equates to engine turns 5.8185185 times for every spin of the rear PTO shaft

Cool - Info is IN! ... Now the question is, What is the nature of implement you see for use. Does this include many that want continuous full flow and rated pressure at the same time? Like a blower, rototiller, [or to lesser extent a mower because you can vary ground speed,] for instance. ... Or do you see major use on ones where nominal implement speed is not much concern, but resistance to motion can vary greatly. Such as sickle bar cutting brush, a post auger, rotary broom, etc.
-- The next question is, What else is the tractor doing?? Are these mobile or creeper, or stationary point of use applications? Go with too large a pump the tractor wont walk and chew gum.

... Looking at the table and 3200 engine graph it looks like the SP20B16 is a very good choice considering "Net Intermitent HP". You will be close to being able to sustain 3000PSI at 10+ GPM. [3200x.8216 = 2630pump speed.] You have essentially the same eng HP down to 2800 rpm where the pump will be turning slower and using less power. So you will be able to move around a little even with an implement working hard enuf that it wants 3000PSI. Not too touchy. Going down a pump size would ensure that it not be touchy at all, but may not be acceptable for speed sensitive implements. Going up a size would handle flow for sensitive speed implements, but the balance would go against the engine if they also needed hi pressure. You could leave the pressure relief high for implements encountering brief high resistance. The engine and tool would then power thru while eng rpm plummeted. Moving while working hard would be very touchy keeping the eng from lugging below its happy work range.
...larry

 

[J_J]

Artisan,

I have these specs on my B9200 HST. Do you have similar specs on your tractor?

Power Take-off (PTO):
Rear PTO: live
Rear RPMs: 540/748
Mid RPMs: 1847/2557

 

[Artisan]

Dare I say Artisan is develping a belly mount post hole digger?

HA! That would be a trick ehh? Perhaps a belly mounted hydraulic powerplant might better describe it, after that, run what ya brung!

 

[Artisan]

Artisan,

I have these specs on my B9200 HST. Do you have similar specs on your tractor?

Power Take-off (PTO):
Rear PTO: live
Rear RPMs: 540/748
Mid RPMs: 1847/2557

J_J I don't quite understand your specs, alls I find for a BX25 is this;

 

[Artisan]

Cool - Info is IN! ... Now the question is, What is the nature of implement you see for use. Does this include many that want continuous full flow and rated pressure at the same time? Like a blower, rototiller, [or to lesser extent a mower because you can vary ground speed,] for instance. ... Or do you see major use on ones where nominal implement speed is not much concern, but resistance to motion can vary greatly. Such as sickle bar cutting brush, a post auger, rotary broom, etc.
-- The next question is, What else is the tractor doing?? Are these mobile or creeper, or stationary point of use applications? Go with too large a pump the tractor wont walk and chew gum.

... Looking at the table and 3200 engine graph it looks like the SP20B16 is a very good choice considering "Net Intermitent HP". You will be close to being able to sustain 3000PSI at 10+ GPM. [3200x.8216 = 2630pump speed.] You have essentially the same eng HP down to 2800 rpm where the pump will be turning slower and using less power. So you will be able to move around a little even with an implement working hard enuf that it wants 3000PSI. Not too touchy. Going down a pump size would ensure that it not be touchy at all, but may not be acceptable for speed sensitive implements. Going up a size would handle flow for sensitive speed implements, but the balance would go against the engine if they also needed hi pressure. You could leave the pressure relief high for implements encountering brief high resistance. The engine and tool would then power thru while eng rpm plummeted. Moving while working hard would be very touchy keeping the eng from lugging below its happy work range.
...larry

Larry you da' man! WOW, knowledgeable is an understatement...

In a perfect world I would want "A" pump that will do it all, obviously
that is not going to happen. The pump I picked might be somewhat OK
but looks like a guy that wants it all would want to keep 3 pumps on hand
if a guy had all those varied demand implements in stock, switching
pumps with each different implement, tractor usage change. Certainly an
expensive way to go but, indeed necessary depending on implement used
and what demands you will put on the tractor itself robbing power from
the PTO.

If I have not said it before I will say I think the thing to do is build a
system as robust as possible w/ the given HP and RPM's, see what she'll
do and then look for tools that will run off what I built.

Tools I could use ...

Chainsaw 8GPM
Post Driver (interesting "Oil Dividers" they sell)
Auger
A powerplant for my Weatherhead hydraulic hose maker!

I am sure if I get a tank hung and a universal pump bracket I can figure out other things to do w/ it.