building a hydraulic power unit , i need help

[bobtree]

Hi, this is my first time so be gentle!
I am planning to build a hydraulic power unit using a D1305e 30 hp kubota deisel engine,22kw ,3000 rpm.The unit will be running a log splitter with 4 inch cylinder at 200 bar. I have been told by an on line hydraulic parts company that the engine will run a 40 gpm pump ,the pump is a single stage 200 bar and runs at 2500rpm.disp.61.1.
I would like to run the pump direct drive it seems that the engine outputs 28hp at 2500rpm according to kubota.
so my queston is "will the engine run the pump for the purpose intended"
I would appreciate any helpful input.

 

[J_J]

If it is in fact a 40 GPM pump, then it will take about 79 HP to run it at 2900 psi. Efficiency about 85%

A pump with 3.7 cu in displacement, turning at 2500 rpm will put out 40 GPM.

I don't understand what this number is.

disp.61.1.

 

[DJNebraska]

28 (HP) x 1714 (magic number) = 47992 / 2900 (PSI) = 16.55 (GPM theoretical) * 0.90 (efficiency on a gear pump) = 14.90 (GPM actual).

14.90 GPM is the top end flow you'll be able to run at 2900 PSI.

16.55 (GPM theoretical) x 231 (cubic inches of fluid in a gallon) = 3823 (total cubic inches) / 2500 (RPM) = 1.53 (cubic inch displacement of pump you need).

Hope this helps!

 

[J_J]

bobtree,

The answer to your question is NO.

You only have 28 HP total.

You are going to have to live with about 14 GPM max at that pressure.

A PTO pump will provide about 21 GPM, but at 2000 psi.

What were you going to do with your intended hyd GPM's?

 

[oldnslo]

Hi, this is my first time so be gentle!
I am planning to build a hydraulic power unit using a D1305e 30 hp kubota deisel engine,22kw ,3000 rpm.The unit will be running a log splitter with 4 inch cylinder at 200 bar. I have been told by an on line hydraulic parts company that the engine will run a 40 gpm pump ,the pump is a single stage 200 bar and runs at 2500rpm.disp.61.1.
I would like to run the pump direct drive it seems that the engine outputs 28hp at 2500rpm according to kubota.
so my queston is "will the engine run the pump for the purpose intended"
I would appreciate any helpful input.

I presume the displacement of 61.1 is in CC/rev since all of the rest of the information is metric. 61.1 cc/rev = 3.73 CIR which at 3000 RPM is 48.4 GPM and like the others have said, NO this motor will not drive that pump at 200 Bar.

Your motor would drive that pump at around 65 bar.

Roy

 

[bobtree]

Thanks for the input, sorry the displacement was 61.1 cm3 (3.73in3) ,I am from the uk and have been brainwashed .I thought the pump sounded a little on the big side but was probably hoping my calculations were wrong. I was thinking big pump ,faster log splitter to **** with the laws of physics.

I guess the next question is do i get a 2 stage pump or single stage pump ?

 

[oldnslo]

If just for a log splitter two stage will provide the higher flows at lower pressures for speed and lower flows higher pressure for work.

P.S. Being from the UK doesn't make you brain washed.

Roy

 

[bobtree]

Thanks for the advice guys !

Bob

 

[J_J]

Thanks for the input, sorry the displacement was 61.1 cm3 (3.73in3) ,I am from the uk and have been brainwashed .I thought the pump sounded a little on the big side but was probably hoping my calculations were wrong. I was thinking big pump ,faster log splitter to **** with the laws of physics.

I guess the next question is do i get a 2 stage pump or single stage pump ?

How much engine HP do you have to power a pump. Single stage will require a larger HP for the high GPM.

A 16 GPM two stage hyd pump only requires about 8 HP. Where as the 16 GPM single stage pump requires about 27 HP at 2500 psi.

Surplus Center - 16 GPM 2 STAGE HYD PUMP S21707-5185

With this pump, you will get about 3 GPM at 3000 psi, and 16 GPM at about. 700 psi

 

[leonz]

Thanks for the input, sorry the displacement was 61.1 cm3 (3.73in3) ,I am from the uk and have been brainwashed .I thought the pump sounded a little on the big side but was probably hoping my calculations were wrong. I was thinking big pump ,faster log splitter to **** with the laws of physics.

I guess the next question is do I get a 2 stage pump or single stage pump ?

Your not brainwashed, the metric system is still simpler to use.


Your hydraulic cylinder piping/hose size is going to determine the fluid flow volume per cycle.

A smaller cylinder will cycle faster BUT a larger pump with slightly larger cylinder will work faster and become hotter sooner improving the oils flowability and pressure characteristics as hot oil is a log splitters friend.

If your fabricating your own frankestien keeping it simple would
be preferred and here is how to do it.

A manualy operated Rockford PTO CLUTCH

A 16 gallon per minute open center Vickers Vane Pump
which will mount easily to the Rockford P.T.O., clutch

The vane pump would be plumbed into the base and the pilot operated valve is fed from the base mounting to control the cylinder.



A Vickers pilot operated control valve and valve base.

3 disposable gas/oil accumulators for the piston side of the cylinder oil flow from the pressure side valve to aid in more efficient splitting.


A fourty gallon hydraulic tank with an inlet oil screen for filtration and MENT TO BE USED AS A HYDRAULIC RESERVOIR!!!!!

You have understand that this oil is going to be cold and a vane pump will be better able to deal with cold oil temperatures and heat the oil sooner to operating temperature.

The Vickers vane pump will also be better suited for the Kubota power plant
and will be better able to provide more power to the accumulators and the cylinder as it can operate at lower engine speeds to 1,750 R.P.M., as it is a direct drive unit.

A vickers vane pump will be easier to repair and maintain as all that is required is a pump cartridge and new seals to replace it on the machine.

A vane pump requires flooded suction and will not cavitate as easily as a gear pump.




After more investigating by you will most likely find that purchasing a premanufactured hydraulic power unit and a small generator head attached
to the Kubota power to provide electricity for the power unit will cost you less money overall though.