Rio_Grande
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Just currious if there is a difinitive size hydraulic resivour that is necessart on a splitter runnung a 5x24 cylnder?
how much resivor for log splitter?
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oldnslo
Super Member
What size pump and motor will usually have more influence on reservoirsize than the cylinder. Also when are you going to be using it. Winter Vs summer for heat load concerns.
I don't know if there are any "rule of thumbs" for a splitter but I would always want minimum of at least as much reservoir as the slow stage of a two stage pump.
Roy
OP
Rio_Grande
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This is a keep it simple and cheap build, so going with 13 gpm pump. I was thinking about buying a 5 gallon tank, but got to thinking leaving room for expansion, not so sure that is big enough.
DJNebraska
Bronze Member
5 gallons is too small, IMO.
The experts will tell you 4 times the GPM of the pump.
If it were mine, I would make it a 15-20 gallon tank. You should be fine with that.
The experts will tell you 4 times the GPM of the pump.
If it were mine, I would make it a 15-20 gallon tank. You should be fine with that.
the minimum should be .75 of the gpm that is bare min. the rule of thumb is gpm x 1 on a homeowner unit , gpm x 2 on a commecial unit , the oil volume over and above the operation volume needed to fill all lines and cylinder only serves to lower operating temp , thus reducing wear I have built over fifty commercial splitters and have never heard of four times gpm a new 11gpm pump is about 100 dollars and oil is about 8.00 per gallon so I tend to disagree with overly large tanks
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LD1
Epic Contributor
The 4x's GPM and 1x's GPM yada yada all depends on what spec you use for a two stage pump.
If ya use the 13GPM spec, .75 or 1x's the GPM is what to use. So a 10-13 gallon tank.
But on HIGH pressure Low Volume, the pump is probabally only like 3GPM. So use the 4x's # for that. so 4 x 3 =12 gallons.
I personally like to keep things simple. So if It were me, I'd go with either a 10 or 15 gallon TOTAL capacity. NOTHING in between. That way, when you buy 5 gallon buckets of fluid, you dont have partial buckets sitting around.
But I agree, 5 gallons is WAY too small for that pump.
And on a side note, a logsplitter hydraulics is considered continuous use. You can get by with smaller resivours on NON-continuous use things, like dumps beds that dump once and then you are done for awhile and things have a chance to cool. For example, the last dump bed I did was a 3.5 GPM pump and I only used a 2.5 gallon resivoir:thumbsup:
If ya use the 13GPM spec, .75 or 1x's the GPM is what to use. So a 10-13 gallon tank.
But on HIGH pressure Low Volume, the pump is probabally only like 3GPM. So use the 4x's # for that. so 4 x 3 =12 gallons.
I personally like to keep things simple. So if It were me, I'd go with either a 10 or 15 gallon TOTAL capacity. NOTHING in between. That way, when you buy 5 gallon buckets of fluid, you dont have partial buckets sitting around.
But I agree, 5 gallons is WAY too small for that pump.
And on a side note, a logsplitter hydraulics is considered continuous use. You can get by with smaller resivours on NON-continuous use things, like dumps beds that dump once and then you are done for awhile and things have a chance to cool. For example, the last dump bed I did was a 3.5 GPM pump and I only used a 2.5 gallon resivoir:thumbsup:
oldnslo
Super Member
3 to 4 times pump capacity is pretty standard on industrial systems. On mobile systems that number is usually not valid.
I agree a 10 - 15 GPM reservoir should be adequate as long as the lines and valves are sized properly to reduce pressure loss / heat rise.
I agree a 10 - 15 GPM reservoir should be adequate as long as the lines and valves are sized properly to reduce pressure loss / heat rise.
oldnslo
Super Member
And you probably won't see a 44 gallon reservoir on a 11 GPM splitter.
What you will see is a 40 - 50 Gallon reservoir on an industrial piece of equipment sitting in a factory running 24/7 or 6000 hrs per year for years. Yes they will spend more on oil up front that they spend on the pump but.. When you are talking a line shut down that costs $100's or $1000's per minute down time, the oil is cheap.
How many home owner logsplitters run 100 hrs per year?
That was the basis behind my earlier post.
Roy
LD1
Epic Contributor
I mentioned earlier, and what you guys seem to be forgetting, is that a 11gpm 2-stage logsplitter pump is NOT really an 11gpm pump. The 11 gpm is ONLY at 600 psi or so. It is ONLY a ~3gpm pump up to the 3000psi.
SO...3 gpm times a factor of 4 is 12 gallon resivoir. And that is about right.
An ACTUAL 11 gpm pump would need about a 25 hp motor to run. AND if you were indeed running 11GPM @ max PSI (3000 or so), you'd better darn have more than a 10-15 gallon tank:confused2:
DJNebraska
Bronze Member
In reality, an 11 GPM 2-stage pump is an 11 GPM pump, not a 3 gallon pump. It doesn't matter what the low stage flow rate is when it comes to sizing a tank. What matters is system pressure drop when the system is not doing any work.
So what happens with the high flow stage of a 2-stage pump when it is operating above approximately 600 PSI? You guessed it, it's turned into heat. 8 GPM x 600 PSI = 2.8 HP of heat. That's a lot of heat for any system to dissipate. Luckily the pump spends little time in this state.
If you really want to get technical you can figure the heat dissipation capabilities of your tank.
CHAPTER 6: Hydraulic reservoirs
When using the formula, make sure NOT to count any area on the tank that is not in contact with the fluid. Typically the bottom of the tank will not dissipate heat unless air is being forced underneath it. Painting the tank a lighter color also helps.
So what happens with the high flow stage of a 2-stage pump when it is operating above approximately 600 PSI? You guessed it, it's turned into heat. 8 GPM x 600 PSI = 2.8 HP of heat. That's a lot of heat for any system to dissipate. Luckily the pump spends little time in this state.
If you really want to get technical you can figure the heat dissipation capabilities of your tank.
CHAPTER 6: Hydraulic reservoirs
When using the formula, make sure NOT to count any area on the tank that is not in contact with the fluid. Typically the bottom of the tank will not dissipate heat unless air is being forced underneath it. Painting the tank a lighter color also helps.
LD1
Epic Contributor
I perfer the KISS method.
YES, it is an 11GPM pump. But in the context where I said it was NOT, had to do with calculating tank size using the basic rule of 4x's GPM. Someone implied that using that rule, an 11GPM 2-stage would require a 44 gal resivoir. And that is simply NOT the case.
When using a 2-stage pump, you can either take 1x's the high flow, or 4x's the low flow amount.
No need for all of these complexities and arguing back and forth. A splitter is NOT a complex hydraulic system. A 10 or 15 gallon tank for the OP's build is going to be more than enough.
DJNebraska
Bronze Member
10 gallons may not be enough in Tucson, AZ when it's 115 degrees F. We don't know where Rio_Grande is located. The name Rio_Grande leads me to believe the system could be operated in very warm conditions.
Nobody is arguing the fact that a log-splitter hydraulic system is probably one of the most simple hydraulic systems around.
My only point is that skimping on 5 gallons of oil is one of the simplest mistakes a person can make in designing ANY hydraulic system.
Nobody is arguing the fact that a log-splitter hydraulic system is probably one of the most simple hydraulic systems around.
My only point is that skimping on 5 gallons of oil is one of the simplest mistakes a person can make in designing ANY hydraulic system.
J_J
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I would think 8 GPM because the splitter is intermittent in use. It is either splitting wood, or just pumping fluid with little pressure. A good return filter is necessary.
oldnslo
Super Member
DJ,
This is incorrect on a true two-stage pump. When the pressure exceeds the switch over point the hi-flow section is unloaded at very low pressure drop. I.e. the inlet port and outlet ports are connected. The low flow, high pressure side keeps the unloading valve shifted.
see the attached schematic. Hopfully it will help explain this better.
Roy
DJNebraska
Bronze Member
I love being wrong.
Nom nom nom...*eats crow*
Thanks Mr. Old and Slow.
Nom nom nom...*eats crow*
Thanks Mr. Old and Slow.
J_J
Super Star Member
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With all due respects, I don't think you will see large hyd tanks on log splitters. For one thing, in most splitting conditions, the pressure is not very high and the hyd system is just loafing, doing min work. You could probably run the splitter all day using a 5 gal hyd tank, with a 11 GPM two stage pump.
Deere Dude
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A 37 ton splitter with a 5x24" cylinder and a 16 GPM 2 stage pump uses a 9 gallon reservoir, in Northern Tool. Why reengineer something that they sell hundreds of? I run a 22 ton with a 4" cylinder all day long in hot weather and the oil gets warm to the touch and that's about it. It has a 5 gallon reservoir. 6x5x36".:thumbsup:
