How many HP do I need to run a 22gpm pump to 2500 PSI? I seem to think I read 16 somewhere.
Ian
Ian
I just can't resist. Since I have the real world example. Both me and Earl have the exact same beam and cylinder assembly. We have tested both splitters in the same pile side beside and no matter how you slice it or dice it the single stage pump is way more productive. And I know the math but my Deere can't even tell that 22 GPM pump is on it so I doubt its soaking up 40HP. If it were I would hear the governor kicking in and it doesn't even with the cylinder dead ended. I can out split his stand alone even with the Deere idling. There is still a bunch of apples and oranges here because a Turbo diesel power isn't anything like a small twin gas.I don't want to reopen the past thread arguing how a single speed pump is faster because it never 'shifts down and slows down'. That is true ONLY if you have the 40 hp engine to turn the 22 gpm single stage pump here. That poster mixed apples and oranges big time.
I'm on a 4" cylinder so I don't know for sure how much more oil that cylinder will eat up without doing some math. I'll bet its close. If we are in nasty wood the smaller units spend a fair amount of time shuttling. Your bigger cylinder would limit that. What is your cycle time? Mine is 6sec.I bet my 18 hp briggs with it's 28 gpm 2 speed pump would give yours a run for it's money. It rarely kicks into low and runs mostly in the 28gpm mode. Five inch diameter 24 inch long cylinder with 40 gallon hyd tank.
28 gpm
I'd for sure go the twin cylidner route. I have an 18 hp flat twin and it is smoooooth running about 2500 rpm.
Even at 22 gpm or 28, you only need say 12 hp in low speed at high pressure. BUT the big advantage is you can drive the large flow to higher pressure before unloading the large section. With 10 or 12 hp in example above, it was 650 psi, so the pump unloader needs to be set about there. Anytime load is higher, it unloads the big stage and slows down.
With say 16 hp, still only need 12 hp at 2500 psi unloaded, BUT it can drive the large flow up to maybe 900 psi before stalling the engine. So if you set the unloader properly, you can split 900 psi logs while still at high speed instead of slowing down. Of course if you leave the unloader setting at 650 psi then more hp has done absolutely nothing. And slowing the throttle cuts speed, doesn't change force/pressure at all (unless the system is seriously leaking and worn out).
Since the price jump is a lot from 16 to 22 gpm, (different series of barnes pump with larger body) but not so much from 22 to 28 (same series, just slightly larger gears) if you have the twin cylinder hp available I would for sure go that route, then go 28 gpm pump, especially on a 5 inch cylinder. The price increase ripples, as lines, filter, and spool valve all need to be larger. Larger spool valve is harder to find and not as many built, thus just like the pump the prices are a lot higher then the 11 16 gpm stuff.
kcj
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