1 hp.
= 1 gpm.
@ 1500 psi.
1 hp.
= 0.5 gpm.
@ 3000 psi.
1 hp.
= 2 gpm.
@ 750 psi.
Pushing force
= area of the cylinder x-section
X psi.
Pulling force
= area of the cylinder x-section
minus area of the rod x-section
X psi.
1 gal.
= 231 cubic inches.
Cylinder volume
= x-sectional area
X length of stroke.
Time for full stroke out
= 60
/ gpm. (converted to cu. in.)
/ cylinder volume (cu. in.)
= # of seconds.
A smaller diameter cylinder will require higher pressure to split a given block. If the flow on both splitters was the same, that could explain the larger engine "bogging".
Playing with hydraulics is a numbers game if you want to have a unit that will work at the best efficiency for time, force and horsepower. Lots of math and formulae. There are handbooks available with all the necessary info. I have several.......... somewhere :banghead3, but I haven't been in the right stores to look for them for years. Perhaps Northern Tool?
Here's a couple of study guides.
http://www.edgeroamer.com/sweethaven/mechanics/hydraulics01/
http://www.hydraulicsupermarket.com/technical.html
A 3.5" - 4" diameter cylinder with a 20" - 24" stroke makes an excellent log splitter. Smaller diameters need a lot higher pressure, but a smaller volume to do the same job in the same time.
Oil under pressure can be dangerous if you spring a leak in a line or fitting. The higher the pressure, the greater the danger.
Among that "stuff" is everything I need to build my own log splitter; except for an engine. 3 different cylinders (I will probably pick the longest one) the I beam, the fluid tank, the filter mount, hoses, valve, axle and more.
I wasn't figuring on building one of these since I no longer have my own fireplace; but since I have all the "makings", "why not"?
How do I figure out how big an engine I need for that pump? I've seen spliters from 5-16 HP; some store bought some home made.
I have recently been splitting ALOT of firewood; (something else he needs to find a buyer for in the next few days) and we had a borrowed store bought "MTD" vertical model w/a 6.5HP Briggs vertical engine; and a home made horiz. model w/ an old L head 8HP Briggs. the 6.5 seemed plenty for that machine yet the 8HP seemed under powered. (based on how much the respective engines "bogged" under the load of splitting an average sized log)
is there a chart of "gallons per minute of pump capacity, vs HP required" or does it go by cylinder size, or what?