Need help on rotary broom hydraulic conversion

[MossRoad]

Yes,that tree is still up there.It gets plenty of water from the spring in the clock....:laughing:

AAAhhh!!! That's a good one!!! I laughed hard. Thanks. :laughing:

 

[locknut]

One of the techs at sweepster suggested a motor in the 6-700 rpm range and sized between 4-5 cu in. Pump size 1.2 cu in at 17-1800 psi system pressure at 10-12 gpm. So,I went to the S-Center horsepower requirement calculator and the gpm and psi called for 24-28 HP.Something just doesn't seem right.

 

[MossRoad]

...Something just doesn't seem right.

No sir, it does not.

 

[J_J]

I thought we had already figured out what was needed.

To turn the broom at 554 rpm, you need a 5 cu in motor and 12 GPM.

To develop 12 GPM you need a 1.4 cu in pump, turning at 2000 shaft rpm.

12 GPM, 1800 psi = 15HP

You said something about 8 HP.

8 HP and 1800 psi, .8 cu in pump= 6.5 GPM

6.5 GPM into a 2.8cu in hyd motor = 536 rpm

So what HP engine do you have?

 

[oldnslo]

Locknut,
You have to determine either how much torque is required to drive this broom and figure component sizes based on torque required or how much HP you have available to drive this sweeper and size components based on available HP. One or the other or a combination of both must be determined before final size of components can be determined..

Could you just drive this straight from the front or rear PTO via gearbox or jack shaft, chain and sprocket arrangement. you would only have one direction of rotation this way unless you installed a reversable gear box.

 

[locknut]

No sir, it does not.

No,it doesn't,considering 16-18 HP Case-Ingersoll-John Deere garden tractors run hyd tillers that work well,and in my mind,would take much more torque to operate.The only difference is those tillers are driven right on the shaft at around 100-150 rpm,same as most broom shafts run.The only difference in my setup is running a higher speed motor to power the chain drive,instead of the broom core shaft directly.

 

[locknut]

I thought we had already figured out what was needed.

To turn the broom at 554 rpm, you need a 5 cu in motor and 12 GPM.

To develop 12 GPM you need a 1.4 cu in pump, turning at 2000 shaft rpm.

12 GPM, 1800 psi = 15HP

You said something about 8 HP.

8 HP and 1800 psi, .8 cu in pump= 6.5 GPM

6.5 GPM into a 2.8cu in hyd motor = 536 rpm

So what HP engine do you have?

I mentioned 8HP as a general power requirement,so,like you mentioned earlier,could estimate a system to have similar power available.

The tractor has a 20HP Kohler.I want to keep the power requirement at a level to operate the broom AND run a 24V alternator on the backside of the front PTO drive(normally runs the deck) to power a 24V heater that sucks up 1hp on low and 2hp on high.

Concerning pumps,would a vane pump work? In the confined space I'd like to place a pump, the top ports look better to plumb and the input shafts match the driveshaft size and key width.

Surplus Center

Specifically this one. V10 7-ring 1.39 cu in.Graphs are here;

http://www.go2hydraulics.com/docs/mfr/vickers/vickers-v10-v20-v2010-v2020-vane-pumps.pdf

 

[MossRoad]

We figured out the HP it takes to drive the hydraulic PTO pump on my Power Trac PT425. It puts out 8gpm at 2500psi. That requires about 11.6hp to drive that pump, as the formula at the Surplus Center is:
HP to drive a hydraulic pump=Psi x GPM / 1714.

So going by the numbers provided by sweepster,

1700psi X 12gpm / 1714 = 11.9hp required to turn the pump.
As long as your front PTO can provide 11.9 hp or better at 2000RPM, you would be fine.

 

[locknut]

Locknut,
You have to determine either how much torque is required to drive this broom and figure component sizes based on torque required or how much HP you have available to drive this sweeper and size components based on available HP. One or the other or a combination of both must be determined before final size of components can be determined..

Could you just drive this straight from the front or rear PTO via gearbox or jack shaft, chain and sprocket arrangement. you would only have one direction of rotation this way unless you installed a reversable gear box.

Well,that's the thing I asked the sweepster techs and they did not know the torque requirement at the 540rpm drive input to the chain loop.From what they suggested,the torque would be around 1100 in lbs. I've looked hard for another gear driven solution and so far empty handed,especially being able to turn the broom 30deg left or right.

 

[locknut]

We figured out the HP it takes to drive the hydraulic PTO pump on my Power Trac PT425. It puts out 8gpm at 2500psi. That requires about 11.6hp to drive that pump, as the formula at the Surplus Center is:
HP to drive a hydraulic pump=Psi x GPM / 1714.

So going by the numbers provided by sweepster,

1700psi X 12gpm / 1714 = 11.9hp required to turn the pump.
As long as your front PTO can provide 11.9 hp or better at 2000RPM, you would be fine.

Your formula works out to that but the calculator at SC says 14HP and to double that for a gas engine.

Surplus Center

 

[MossRoad]

Your formula works out to that but the calculator at SC says 14HP and to double that for a gas engine.

Surplus Center

Well aint that a kick in the $%^$# grrrr...

Anyhow, with a 20hp kohler I think it will be weak running both a broom and an alternator pulling that much HP off of a 2000 rpm PTO, and you still need power for forward and reverse. Why? Because that high speed PTO will have low torque and that's what you need in this application. A lawn mower deck needs high speed and lower torque, VS a tiller or broom that needs low speed and high torque.

Perhaps more info on the tractor would be helpful at this point. Model, specs, etc....

 

[J_J]

Just tell us the HP you have available and the rpm of the sweeper.

Hp to drive hydraulic pump = Psi x GPM / 1714

 

[oldnslo]

Locknut,
For ference: Here is a link to a company that build brooms for loaders. There specs all show 18 CIR motors for direct drive on brooms up to 7 feet.

Skid Steer Sweeper | Loader Sweeper › M-B Companies, Inc.

 

[J_J]

Seems like those 6 to 7 ft sweepers only run about 175 to about 250 rpm.

Flow requirement is about 20 GPM.

Motors are rated to 2500 to 3000 psi.

 

[Leejohn]

If you are interested? Here is the motor I have SC part #981-1003.

 

[locknut]

Well aint that a kick in the $%^$# grrrr...

Anyhow, with a 20hp kohler I think it will be weak running both a broom and an alternator pulling that much HP off of a 2000 rpm PTO, and you still need power for forward and reverse. Why? Because that high speed PTO will have low torque and that's what you need in this application. A lawn mower deck needs high speed and lower torque, VS a tiller or broom that needs low speed and high torque.

Perhaps more info on the tractor would be helpful at this point. Model, specs, etc....

Agco 2020,same as Simplicity Legacy 20HP Kohler..Similar size and setup as a JD 420 with an electric clutch right off the crank to a lower larger pulley and pto shaft designed to run around 2000rpm for mower deck or front snow blower.

 

[locknut]

Just tell us the HP you have available and the rpm of the sweeper.

Hp to drive hydraulic pump = Psi x GPM / 1714

20 HP Sweeper core runs at 135rpm which is driven by a 48T sprocket on a chain loop driven by a 12T sprocket on the hex bar shaft which the speed is 540 rpm and where I want the motor to be mounted.I really need to find out how much torque is needed on that hex bar shaft.I wish I had a large cordless drill that would output 5-600 in lbs @ 4-500 rpm.I'd strap it down and see what the broom could sweep with that input.

Did you check the specs and graphs on that vane pump?

 

[MossRoad]

So the front PTO is a pulley?

 

[locknut]

If you are interested? Here is the motor I have SC part #981-1003.

Thanks for checking that out.I think it's a little too large,but I'll keep it in mind.Thanks.

 

[locknut]

So the front PTO is a pulley?

No,the pulley is driven by two belts to the electric clutch pulley above it,pulley is mounted on a double-ended splined driveshaft that runs straight thru the center of the front axle.The rear spline is for a shaft driven deck and the front is for a 47" two-stage blower,60" rotary broom,or a factory hyd pump for a loader or other attachments.Can't find any specs for that pump,not that it matters for this project.