BX25 Mid PTO Pump or BUST

[rambler]

As far as my source, we will not be giving that up anytime soon, I assure
you, NOTHING "BlackMarket" nor GreyMarket happening here...

I probably should keep quiet, as I enjoy reading on your progress on this un-needed but fun to create project and I don't want to make this a bad thread.....

But, considering how much everyone is helping you here, I found your attitude and comments to appear a bit selfish. Jus struck me as odd that you are unwilling to share, among people that are sharing so much with you. Might want to reflect upon that a bit.

Don't mean to make this a big deal, I won't harp on it again.

--->Paul

 

[J_J]

When Artisan selects his pump, it will have to fit the rpm limits of the mid PTO, which is 2250 rpm, probably a gear pump with a fixed displacement.

With 17 HP at the mid PTO, max engine rpm, he needs 1.0 cu in of displacement to pump 10 GPM. There is no or very little pressure until a hyd motor is operating within the hyd motor parameters under a load.

Once a pump is selected, you are limited to the GPM that the pump provides. Pressure will vary. You can not generate more volume/GPM unless you increase the rpm on the motor.

A hyd motor using this 10 GPM from the pump can run satisfactory up to the hyd motors pressure limit. There may be a running pressure and a peak pressure. You will stall the engine if reliefs are not used.

Someone mentioned about using a lower pressure to get more GPM's. The hyd motor load will determine the pressure. If you put a relief valve across the motor control, set at 2500 psi, it is lower than the pumps capability of 3000 psi, the 3000 psi hyd motor is not going to develop it's max torque.

Example hyd motor

SPECIFICATIONS
Disp. 0.37 cu. in. / rev.
Pump Type Gear
Rotation CW
Pressure:
2900 PSI rated
3480 PSI peak
Speed:
2000 RPM rated
4000 RPM max.
Flow:
2.98 GPM rated.
5.96 GPM max.

Example pump


Brand new EATON Model 26000. Replaces Cessna 26300 Series. Hydraulic gear pump. Ideal for replacement on mobile equipment and other hydraulic systems.

SPECIFICATIONS

3000 PSI max
SAE A 2 bolt mount
Side ports IN SAE 16, OUT SAE 10
Shaft 3/4" dia x 1 1/4" w/keyway
CW rotation
1.02 cu in displ/rev
3200 max RPM
Rated GPM at 2500 PSI:
14.4 @ Max RPM
7.9 @ 1800 RPM
Shpg 7 lbs

 

[SPYDERLK]

You do have the power to flow more than 10gpm.

At fixed HP, as pressure goes up flow goes down. Conversely as flow goes up pressure goes down. Only fixed number is your HP in this case.

Most hydraulic systems use between 2000-3000psi. Some use much less, some much more.

To explain my suggestion a little better. Go for a flow rate of 12-14 gpm at full throttle. You will want a pressure relief in the system of no more than 3000psi to protect hoses, pump, fittings, etc. (for your application)

Your available HP will not give you full flow (12-14gpm) at relief pressure (3000psi) What I'm saying is that you don't have to limit your flow based on HP. The HP is the limit of the work you can get from your tractor, not a limit of either flow or pressure.

The only reason to build within those limits is stall protection. You don't have to build in stall protection. If you want to have that feature you can adjust your relief pressure, you will still be getting the full working potential of your horsepower (minus system efficiency derating).

Anyway, just a friendly suggestion, with the goal of giving you more options. I'll be following your project with interest.



Mr. HE

The key point is that he will not be able to produce good pressure with available HP driving a large pump. He will need pressure up to about 3K to get good torque performance from standard motored implements -- a valuable compatibility. With a large pump his engine would stall, or lug down to a near stall condition trying to produce this pressure. Now, if he was making all his own implements he could use larger motors to get needed torque from the lower pressure dictated be the large pump and limited HP. Whichever way, the motors will run a little slow. Every trade robs peter the exact amount you pay paul.
larry

 

[EE_Bota]

If I had to try to get more power off the BX, I'd assume I could get close to the rated PTO HP out of the thing, but I would probably choose to do so by taking it off the flywheel, which is up front. I would save myself the control work (easy for me) and the expense (yikes.) I would use an appropriately sized two stage splitter pump.

I don't think my suggestion comes from ignorance, but there's that too.
I don't know all the components that exist, nor all you could scare up, but my methods of doing high volume /low pressure to low volume / high pressure are best suited for an industrial setting. I do this all the time in industrial.

If your BX is like my BX2200, the PTO is gear driven, but hydraulic clutch pack actuated. So for practical purposes...gear driven.

"Power is power."

In the thread where people were looking for tricks, I couldn't help but think "power is power." Fluid power, mechanical power, electrical power..."power is power." There are caveats...having to do with quality of power and overall utility of power, but power truly is power. Work/time...rate of doing work.

 

[J_J]

There must be a good reason that tractors don't use clutch type hyd pumps, ran off the fan belt for the hyd system.

Doesn't matter how you do it, you only have so many HP, and it is what it is. That is your limitation.

Although my Power-Trac has three hyd pumps and one of them is driven off the fan belt. It is a 1 to 3 GPM pump at 3000 psi. used for steering and loader work.

 

[hddnis]

The key point is that he will not be able to produce good pressure with available HP driving a large pump. He will need pressure up to about 3K to get good torque performance from standard motored implements -- a valuable compatibility. With a large pump his engine would stall, or lug down to a near stall condition trying to produce this pressure. Now, if he was making all his own implements he could use larger motors to get needed torque from the lower pressure dictated be the large pump and limited HP. Whichever way, the motors will run a little slow. Every trade robs peter the exact amount you pay paul.
larry

Well aware of all that. I'm only suggesting copying standard specifications, that fit within the horsepower rating of his machine, to give him a wide range of attachments he could run if he wanted to.

Toro Dingo 220
20 HP
10.8gpm
3000psi relief

Bobcat MT52
18.8HP
12gpm
2900psi

Ditchwitch SK350
20HP
12gpm
2300psi


I could go on, but my point is that my suggestion was standardized specs that would give him a huge range of attachments to choose from. Clearly many of those machines will stall the motor if they run up to full system pressure. That happens, I've run all of them and more. The key to those attachments working is flow, not pressure. They rarely ever hit pressure relief. I'm suggesting proven design parameters. I know they go against conventional hydraulic "wisdom", but it works, every day, on tens of thousands of commercially produced machines. Some tweak the relief pressure, some don't, but they all have a higher flow rating and have the same or less horsepower than the tractor in question.



Mr. HE

 

[Artisan]

I am still having some connectivity issues, hard to post when it takes 2
minutes for these pages to appear, each and every click , 2 minutes of wait.

The conversation is awesome. I still don't completely understand it all,
but each day I seem to grab another piece of of the pie. I think
I know what pump I will get first, and I won't be "selfish" keeping it to
myself as I have been accused of, I will address that unfounded
accusation soon, not here this second.

I believe I made some progress. I spent some time on my back staring at
the undercarriage and looking for an efficient, solid way to hang a pump and
I think I am on to something. I drew up a few parts in CAD and emailed
it to a local water-jet company for cutting. I have a feeling it will be one
of many. Not due to flaw, but a guy could have several different pumps
for different tools, two or four bolt, maybe a combo 2/4 bolt mount?


Selecting a pump might be childsplay compared to a properly sized fluid
tank and it's placement, all in trying to keep it looking decent, not
silly or garish and or loosing too much ground clearance. I believe I
need to have a 10 gallon minimum tank* That's a lot of volume to squeeze
in someplace.
*Now if it is a log splitter pump I am told a 28GPM (No load rated) pump
needs 30 gallons, or add a fan powered cooler. I kinda like the cooler idea.


1-I could pull the BH off and make a tank carrier off the 3PT, but then I don't
have my beloved BH and that defeats the whole excercise, that being to
find a use for the Mid PTO for us guys who don't mow.

2-I could hang a tank from the MMM lowering arm spring mounts at the
rear, and make a hinged tab off my pump bracket front, but I will
loose ground clearance, it would put the tank, under the pump inlet maybe
6" as well, will these pumps suck and self prime even a little? What if I
hung a tank that is maybe 33"W x 18"L x 4" Tall, 2376 cubic inchs =
10.285714286 gallons [US, liquid]. We loose 4" ground clearance.
Perhaps vertical baffles for some in case of bottoming out ridigity and
.25" material...
If a guy mounts a Kubota sweeper or snow blower he reduces the
clearance at the front axle down to about 3.75" , there would still be 9 or
so inches under tractor center and well above the rear axle bash-bar if I did
a MMTank, "IF" I can have the tank a few inches under the pump. Wait,
what if I had a filler neck that protruded a couple inches higher than
the pumps inlet, THAT might work... . So is there any reason why I can't
hang a tank from the MMM Spring loaded rear mounts? When raised and
weight on we have a tank and 10 gallons, maybe on the outside 140 pounds?

3- I looked at it and thought about making a "U" shaped tank that wraps
around the lower part of the engine cowl, interesting, on a BX25 the
exhaust kinda kills that idea.

4- I guess I could remove the BullBar and make a vertical tank on front
of the headlights but nawh...kinda hokey. I like my builds to look store-bought, when possible.

5- How about a tank shaped like the inside of the FEL bucket? If I hung
an auger the tank would always be higher then the pump, it would not be
real hard to do. Heck a guy could drill holes in the bucket and use
bulkhead fittings for the hoses and maybe double them to hold the tank
down...hmmm...lots of long hoses...

6-How about loosing the FEL Bucket all together and ...TO BE CONTINUED...

 

[bcp]

For a tank, hang 2 pipes (6x48) crossways under the loader arms behind the bucket. It won't interfere with loader operation.

Bruce

 

[Artisan]

For a tank, hang 2 pipes (6x48) crossways under the loader arms behind the bucket. It won't interfere with loader operation.

Bruce

No bad less the wheels are I think 44.5" Left to Right. You have 11.75 Gallons, Thanx Bruce! That's thinkin out the box! I had another gent
email w/ a 2 pipe suggestion as well. Pipes were the first thing I thought
of, heck 4' COPPER! HA! prob 40bux a foot. I drew up a belly tank
this am that might be a-ok.

 

[SPYDERLK]

Theres the ROPs tube. Not much volume but a great radiator.
larry

 

[magicheater]

Theres the ROPs tube. Not much volume but a great radiator.
larry

That's for sure but a foldable ROPS would have a problem though.....

 

[SPYDERLK]

Well aware of all that. I'm only suggesting copying standard specifications, that fit within the horsepower rating of his machine, to give him a wide range of attachments he could run if he wanted to.

Toro Dingo 220
20 HP
10.8gpm
3000psi relief

Bobcat MT52
18.8HP
12gpm
2900psi

Ditchwitch SK350
20HP
12gpm
2300psi


I could go on, but my point is that my suggestion was standardized specs that would give him a huge range of attachments to choose from. Clearly many of those machines will stall the motor if they run up to full system pressure. That happens, I've run all of them and more. The key to those attachments working is flow, not pressure. They rarely ever hit pressure relief. I'm suggesting proven design parameters. I know they go against conventional hydraulic "wisdom", but it works, every day, on tens of thousands of commercially produced machines. Some tweak the relief pressure, some don't, but they all have a higher flow rating and have the same or less horsepower than the tractor in question.
Mr. HE

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

 

[Iplayfarmer]

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

Are those implements going to run better at full pressure, partial flow? Or are they going to run better at full flow partial pressure?

My bet it full flow partial pressure. How often to you activate your safety bypass pressure setting while using a power broom, etc.?

 

[SPYDERLK]

Are those implements going to run better at full pressure, partial flow? Or are they going to run better at full flow partial pressure?

My bet it full flow partial pressure. How often to you activate your safety bypass pressure setting while using a power broom, etc.?

But then I run my power broom from the PTO at idle ... far from 540, but pretty hi torque on occasion. With drive by low pressure hydraulics it would just stop. Then, with my HP limited system Id be looking for more pressure than the engine-pump combination could provide. Some implements are full speed critical -- like a mower or blower. Many arent. All implements however are torque critical. Without pressure capability behind the flow youre just out of luck.
larry

 

[Artisan]

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" . Daunser has a hydraulic pump, EP6 that
might do OK. The gent at Danuser suggested
I can prob not spin the dirt off the auger. Not having run one, I am not
sure if that is a big deal or not.

I am drawing up what I think might be a proper circuit, stay
tuned, will she go, or will she BLOW! :laughing:

Log Splittin' is DEFINATELY on my mind, a whole differnt animal I do
believe. My limited knowledge says I am either - or, either a single gear
pump OR a hi/lo pump...I thunk...

 

[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" . Daunser has a hydraulic pump, EP6 that
might do OK. The gent at Danuser suggested
I can prob not spin the dirt off the auger. Not having run one, I am not
sure if that is a big deal or not.

I am drawing up what I think might be a proper circuit, stay
tuned, will she go, or will she BLOW! :laughing:

Log Splittin' is DEFINATELY on my mind, a whole differnt animal I do
believe. My limited knowledge says I am either - or, either a single gear
pump OR a hi/lo pump...I thunk...

Seems that might be 1 size too high ... but close. Can you get a HP vs RPM curve for your engine. And the ratio that the mid pto is driven? It would be nice to see if it will be able to power the pump to 3Kpsi somewhere in the range.
larry

 

[Artisan]

I need to interject...

I am not capable of selecting a pump, I now know enough to be dangerous ,
having said that day by day, bit by bit I am picking up things. I am SUPER APPRECIATIVE
of the input from you guys, some day hopefully I can return
the favors... I'm in Los Angeles, I don't think anyone will be sending me a
commode to tune up any time soon but you pay the shippin' we'll take a
looksee k' ?

(If you ever going to build ask me for what to patrol your plumber on... )

My interject is the gent that suggested this pump suggested perhaps run
the said pump at 2500 PSI. I just can't completely fathom why
but I am sure there is method to the madness. Perhaps when I post up
my proposed circuit more tells will make the tale...

 

[SPYDERLK]

I need to interject...

the gent that suggested this pump suggested perhaps run
the said pump at 2500 PSI. I just can't completely fathom why
but I am sure there is method to the madness. Perhaps when I post up
my proposed circuit more tells will make the tale...

Thats because the HP to run it at 2500psi = [2500/3000] x 20.17 = ~16.8HP. A good ploy. Answer to my question in post above would let us determine if theres anywhere in the rpm range that you could develop 3Kpsi with the system.
larry

 

[Artisan]

Thats because the HP to run it at 2500psi = [2500/3000] x 20.17 = ~16.8HP. A good ploy. Answer to my question in post above would let us determine if theres anywhere in the rpm range that you could develop 3Kpsi with the system.
larry

Making sure I follow you Larry, is this the Question;

And the ratio that the mid pto is driven?

If it is the question I don't understand, if your asking what will the RPM usually be run at, well, based on past posts by others, for the short duration the system is needed between uses, I would say 100% or 2500RPM, pedal to the metal while system is running.

 

[SPYDERLK]

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