Hydraulic pump question

[blackdoggy]

All right I have been looking at dozens and dozens of pumps for this splitter I am working out my question is could use a gear pump for it? I have been looking at these Dynamic aluminum gear pumps that are listed in northern for $99 - $120 these seem cheaper but would they be as quick as a Barnes pump the ones I am looking at are the 0.61 and the 0.97 cu. in. ones?

 

[mga]

GPM: 7.92 @ 3000 RPM

8 gallons per minute won't cut it. and it needs a motor doing 3000 rpms.

there is no cheap way out. get a barnes two stage pump...at least 11/22 gallons per minute. your pump is the heart of your splitter. make it a good one.

 

[blackdoggy]

What about 15.84 GPM with 2900 PSI? Does a higher GPM equal a higher cylinder speed I know it won't help with pressure but won't it speed up things?

 

[Bowtie]

8 gallons per minute won't cut it. and it needs a motor doing 3000 rpms.

there is no cheap way out. get a barnes two stage pump...at least 11/22 gallons per minute. your pump is the heart of your splitter. make it a good one.

That man speaks wisdom, he's right. Only other pump style I ever saw work was the pump off an old combine made for raising/lowering the header. Worked awesome, but good luck trying to find that pump cheaper than a new Barnes 2 stage pump.

 

[triptester]

Standard gear pumps will work for a log splitter if you have a big enough motor or engine to handle the pump. The 2-stage pumps enable you to attain the needed speed and pressure with a much smaller and less expensive engines.
Pump outputs are rated at full RPM's. Small engines are designed to run at full RPM continuously.

 

[mga]

What about 15.84 GPM with 2900 PSI? Does a higher GPM equal a higher cylinder speed I know it won't help with pressure but won't it speed up things?

you in a hurry to split wood?

there's a formula to match your pump, cylinder and RPM's.

here's one of them:

http://www.baumhydraulics.com/calculators/cyl_speed.htm

here's another page to help:

http://www.baumhydraulics.com/pages.php?pageid=4

 

[blackdoggy]

Oh well so much for trying to pinch pennies I will just half to keep my eyes open and see if someone wants to get rid of one on ebay for cheap. I was just thinking if I used this car motor thats nearly free with a cheap gear pump hooked to the belt end I could run things.

 

[drmiller100]

gpm equals speed of ram movement.
30 gallons per minute is about 7 second cycle time wiht 20 inches stroke and 4 inch ram.

gpm times pressure is horsepower. if you run too much gpm for a too small engine, you don't get pressure.

out west a 4 inch ram at 2500 psi so far seems to split most of our wood up to 30 inch diameter if you are a little careful how you do it.

 

[blackdoggy]

Sooo basically every single log splitter made then is under powered right? I mean according to this calculator http://www.surpluscenter.com/Hydraulic.htm you need at least a 22 Hp engine to run a Barnes 11GPM pump in low gear and a 42 Hp engine to run it in high gear if what I am reading is correct. I don't know exactly what horsepower I need all I know is I am not using a little five to eight horse engine and if those calculations are correct then I would be safe idling that car motor at 3000 RPM with the pump hooked to the tranny.

 

[triptester]

A 5.5 hp. engine at 3600 rpm's with a 11 gpm 2-stage pump will put out 11 gpm up to about 500 psi. Then the pump will downshift to 2.9 gpm up to 3000 psi. The output of 11 to 16 gpm 2-stage pumps is reduced to about 1/4 in high pressure mode. The high pressure gpms is what determines the horse power needed.


With a auto engine you will want to find a single stage pump that will give you 16 to 22gpm @1800 rpms and 3000 psi. Idling a auto engine at over 3000 rpms will be a real screamer that won't last long.


When a pump is run at speeds below it's rated rpm output will be reduced accordingly.

 

[ray benson]

Use a 5hp gas motor to drive the 11gpm 2 stage Barnes pump.
Use an 8hp gas motor to drive the 16gpm 2 stage Barnes pump.
Use a 12hp gas motor to drive the 22gpm 2 stage Barnes pump.
http://www.surpluscenter.com/sort.asp?UID=2007120416494196&catname=hydraulic&keyword=HP2S

 

[redprospector]

all I know is I am not using a little five to eight horse engine and if those calculations are correct then I would be safe idling that car motor at 3000 RPM with the pump hooked to the tranny.

If you're hooking the pump to the transmission then 3000 rpm engine speed means nothing, the tail shaft may be turning 2500 rpm, or 2150 rpm, or 1800 rpm depending on the gear ratio of the transmission. Get a shaft to fit the engine, and then direct couple your pump.

Andy

 

[blackdoggy]

Okay thanks guys I am taking notes keep the information coming.

 

[cabinman]

pump moter

Buy a used pump , 40 gal or so,, drive of the front of engine, take the pully off and go to an automotive drive shaft shop, and see If they can order a bolt on part, or make the adaptor, or recommed a machine shop,..with the oversized pump you can idel the engine down and save on FUEL,. etc

 

[cabinman]

Pressure Relef

Be sure there is adquate pressure relef before it gets to the control valve, unless your control valve, can handle 40 gal per,.If a hose blows or a pump shaft breaks, is NOT a pretty site

 

[blackdoggy]

I got the machine shops to make the parts for me and I will be sure to add in a pressure relief valve to my project and get a bracket cut up for this project.

 

[blackdoggy]

Okay now after allot of reading I am seeing now where a two stage is really not much better than a standard gear pump besides the higher GPM on the low pressure side. From what I am seeing if you get a gear pump running at 3600 RPM @ 8GPM with a displacement of 0.517 CI your running more GPM with either equal or higher displacement of a Hi Low pump. So now if this is correct wouldn't item number 10567-1801 or 1027-1801 in northern be a better price and a better push pump for my task?