What If splitter question

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Your capacity will be 25gpm and probably run hot.Generally high gpm valves are bigger inlets and outlets so you will not see full efficiency.And forcing bigger flow through a smaller opening will increase pressure also.You would also be possibly in a dangerous situation since some pro splitters run in the middle single digits ie 6 sec cycle time with a 28 gpm pump.You could get into trouble trying to run such a big pump.
 
It is called a "bottle neck" and you will be creating undue pressure and heat. Not to mention the extra work that the engine will be doing ALL THE TIME.
 
33 gpm at what engine rpm? Just slow your engine speed a little, you should be o.k.
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Exactly what I was going to say. Thats just the maximum. And to add something here that would be an ideal pump because most people forget that the ratings are at max annoying speed. If you got an engine with enough power that can run slower it would be alot more pleasant to be around. What rpm does that pump put out 33gpm? Without seeing I'll bet that a real high rpm pump.
 
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How about an unloader valve feeding a cooler? I have a 16 hp twin Briggs I was thinking about using. The pump is off a big loader I think. The splines on the shaft are striped about half way. Thought I'd take it apart and cut the shaft to a standard size with a key way. Or just weld a flange on it. Already got the motor and the pump would be cheap maybe free. Still looking for a cylinder.
 
2 stage pump?

If it's a two stage, running at a lower rpm should be fine. When the pressure builds it will kick the volume down. If it's a variable displacement that will be fine too.

If however, it's a one stage, positive displacement pump you'll have to be sure the engine can develop enough hp at the lower rpm or it may stall out when you meet heavy resistance.

33 gpm is a lot of flow. You may end up with a cooler or a big reservoir to dump the heat generated.

Sounds like you're on the track to a good machine. With that kind of flow a decent cycle time with a 5 inch cylinder is very real.

Take Care
 
2 stage pump?

If it's a two stage, running at a lower rpm should be fine. When the pressure builds it will kick the volume down. If it's a variable displacement that will be fine too.

If however, it's a one stage, positive displacement pump you'll have to be sure the engine can develop enough hp at the lower rpm or it may stall out when you meet heavy resistance.

33 gpm is a lot of flow. You may end up with a cooler or a big reservoir to dump the heat generated.

Sounds like you're on the track to a good machine. With that kind of flow a decent cycle time with a 5 inch cylinder is very real.
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I personally don't like the 2 stage pumps all that much. I know they work great and allow a much smaller engine to be used but a single stage with enough engine can be a wood eatin machine. On a 5" cylinder it would be all but unstoppable.
 
Swamp Yankee said:
2 stage pump?

If it's a two stage, running at a lower rpm should be fine. When the pressure builds it will kick the volume down. If it's a variable displacement that will be fine too.

If however, it's a one stage, positive displacement pump you'll have to be sure the engine can develop enough hp at the lower rpm or it may stall out when you meet heavy resistance.

33 gpm is a lot of flow. You may end up with a cooler or a big reservoir to dump the heat generated.

Sounds like you're on the track to a good machine. With that kind of flow a decent cycle time with a 5 inch cylinder is very real.

Take Care
Click to expand...

Starting off a project with an way oversized pump, is like asking for problems later on....
better start asking yourself what performance you want to accomplish....like splitting force, cycletime and log lenght ....then after doing the math....take a look what components you need....like pumpsize, cylinder bore and stroke lenght...make sure you engineer for an optimal system pressure....at last get a power unit that can run the whole show....

Notables:
1. Higher pressure take less flow for the same performance. 3000psi is a magic pressure level.....most components take a big price jump if rated over 3000psi.....less flow means less overheat problems...
2.A splitting cycle is at more than 95% made at low pressure. High pressure is only needed at the initial crack of the log. Both high pressure and high flow at the same time will require 2-4 times more engine power.
3. There are 2 ways to get a fast lowpressure cycle and a slow high pressure cycle....A: a 2-stage pump and B: a regenerative function on the directional valve, or a separete regenerative valve on the lines to the cylinder. A "regen" valve function speed up the splitting cycle (extract) up to 2-5 times depending on piston rod diameter.

I have posted about regenerative valves in other threads on this forum
 
Starting off a project with an way oversized pump, is like asking for problems later on....
better start asking yourself what performance you want to accomplish....like splitting force, cycletime and log lenght ....then after doing the math....take a look what components you need....like pumpsize, cylinder bore and stroke lenght...make sure you engineer for an optimal system pressure....at last get a power unit that can run the whole show....

Notables:
1. Higher pressure take less flow for the same performance. 3000psi is a magic pressure level.....most components take a big price jump if rated over 3000psi.....less flow means less overheat problems...
2.A splitting cycle is at more than 95% made at low pressure. High pressure is only needed at the initial crack of the log. Both high pressure and high flow at the same time will require 2-4 times more engine power.
3. There are 2 ways to get a fast lowpressure cycle and a slow high pressure cycle....A: a 2-stage pump and B: a regenerative function on the directional valve, or a separete regenerative valve on the lines to the cylinder. A "regen" valve function speed up the splitting cycle (extract) up to 2-5 times depending on piston rod diameter.

I have posted about regenerative valves in other threads on this forum
Click to expand...

The real live test for all this has already been done and in service. And in previous posts been talked about at length.
2 beam and cylinder assemblies identical. One powered by normal 2 stage and Briggs 6hp and the other 22GPM Prince PTO single stage pump.
Both splitters working side beside on same wood pile. The single stage 22GPM that is a measured 6sec cycle time vs the 2stage at 12sec cycle time on an 11gpm pump. The 22gpm single stage will split 3xs the wood. Way more time is spent shuttled down to low flow than you might think and for some reason more pieces don't split overall than the single running at less pressure. You can run all the numbers you want but I did the test. There is absolutely no heat issue with the 22gpm with adequate oil reservoir. In fact my 21gal tank tuns half full even in the summer just to get the oil warm.
BTW I called on the reg valve. It only for real small like 3gpm pumps. Thats crap. Effectively that solves nothing IMO if it only rated for a tiny bit of flow.
No the Barnes 28gpm 2 stage would be real good as you could get away with a little smaller engine and the extra speed would make up for any shuttle time.
 
The real live test for all this has already been done and in service. And in previous posts been talked about at length.
2 beam and cylinder assemblies identical. One powered by normal 2 stage and Briggs 6hp and the other 22GPM Prince PTO single stage pump.





This is not apples to apples. You are comparing a 6 hp circuit with a 25 hp circuit.
To do your test, you have to put a 2 stage, 11/3 gpm pump on a 6 hp engine, and compare that to a 3 gpm single stage on the same 6 hp engine.
the answer should be obvious.

You have not compared two stage to single stage, you have compared big hp to small hp.

To repeat previous posts, two stage pumps do NOT 'shift down' to less performance. The low speed, high pressure mode is determined by max engine hp. Then they 'shift up' to higher flow at lower pressure with addition of the larger portion. A single stage pump stays in low flow slow speed mode always, regardless of the load pressure. Most of the time your 22 gpm pump is running 500 psi and drawing maybe 6 hp. But anytime the load increases beyond 6 hp, it would not work on a 6 hp engine.
 
I am running one of those 33gpm pumps from northern tools, and I am running a 24hp honda with a 5in ram. cycle time is 7 seconds, that is out and back.
I can tell you that 33gpm is too much for 16hp. I do back off my engine a bit as at full throttle the hyd oil can get hot. My plumbing is large as is the valve body as I am running a large hyd motor for the winch and ram. I kill that 24hp now and then so with a single stage on 16hp with that much gallonage I think you will be pushing the envelope a bit.
One thing I haven't checked is my pressure bypass valve. I have just left it as it was on the machine I took it off of many years ago. I only stall the engine if I don't let go of the lever when the ram is at full return or extended.
 
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This is not apples to apples. You are comparing a 6 hp circuit with a 25 hp circuit.
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No I was trying to say any properly powered single stage will out perform a 2 stage in time savings. My example was that even though the 2 specs were almost 2:1 from each other the actual productivity was 3xs. This is because of time lost waiting for the ram to return. Even with the auto return feature the reality is time is still spent waiting weather its to get to the wood or to get back. Our tests proved a fast single stage can out perform a 2 single by a margin of 3:1. I perfectly know the benefits theory behind the different pumps and there applications.
 
I am running one of those 33gpm pumps from northern tools, and I am running a 24hp honda with a 5in ram. cycle time is 7 seconds, that is out and back.
I can tell you that 33gpm is too much for 16hp. I do back off my engine a bit as at full throttle the hyd oil can get hot. My plumbing is large as is the valve body as I am running a large hyd motor for the winch and ram. I kill that 24hp now and then so with a single stage on 16hp with that much gallonage I think you will be pushing the envelope a bit.
One thing I haven't checked is my pressure bypass valve. I have just left it as it was on the machine I took it off of many years ago. I only stall the engine if I don't let go of the lever when the ram is at full return or extended.
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I set my pressure at 2000psi at the valve. The #'s say even the 60hp I have available should be felt at the governor but it isn't at all. In fact there is no way to tell its on there even if you dead end the stroke and hold it there.
I ran the same set up on a 26 hp gas tractor and it would open the governor a little from time to time but nothing like bogging it down or even close to that. Thats with a 22gpm pump.
 
If you are running it off the pto, you have a gear reduction and pushing 2/3 the capacity of pump I am. I am running direct at around 2400 rpm. I should check the pressure i am putting out. If I am running full bore it will pull down, but give me time to get off the valve. pushing 33 gpm through the relief valve takes hp.
 

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