Advanced log splitter plumbing question

[sean donato]

Nifty idea.

 

[SemperFiSawguy]

Sean what say you on this pump? High pressure side is only 6.2gpm..?
28gpm is only ever on up until 900psi when it shifts? Its rated at 25gpm efficiency..
Are chief pumps chinese or reputable in quality? Check this one out. I see zero reason that cant be ran with a 13hp engine based on the math alone?

https://www.baileyhydraulics.com/Two-Stage-Pumps-Chief-8-09-CID-Rated-GPM-28/

 

[kevin j]

I have not read every reply in this thread so take this with the grain of salt

-A dump valve is not to increase speed, but it's to decrease pressure drop so that a large volume of flow does not have to go back through the spool valve. It allows using a smaller (much cheaper) spool valve and reduces pressure drop. Reduced pressure drop is reduced heat and fuel usage.

-Speed is flow which is determined by the fixed displacement pump. It's not going to change by using a dump valve. There might be some slight efficiency improvement by the components operating at a lower pressure but it's minuscule and probably measuring error.

-Pressure is a result of a resistance of a load, it is not 'created' by a pump. The load creates the resistance and the pressure required to move that load is what the pump has to turn against. If there's no resistance on the pump output there's very little pressure. I so often hear 'no pressure, must be the pump'. I'm talking about fixed displacement gear pump here not pressure compensated variable systems

-The sun valve that you show in your schematic is a pilot operated counterbalance valve. It's purpose in the schematic shown is to meter the flow and control the gravity load from running away when commanded down by the spool valve. A dump valve is usually a pilot operated check valve that is not intended as a metering device. it's intended to be more like a switch, just wide open or closed. Both of the sun cartridge styles will fit in the same cavity for that series.
A PO Ck will usually have lower pressure drop as it will be fully open. A counterbalance valve can create pressure drop and heat when it is metering, but be fully open sometimes, it depends on the circuit details.
What is unique about Sun is that they have their shoulder halfway down instead of at the very top end. Their advertising claim was that this put less mechanical stresses in the spool. Can't say. We used hundreds of sun valves they were great. The more common ISO cavity has locating shoulder at top, simply because it is dimensionally a standard o-ring port and tooling, just drilled deeper. Manufacturing reasons.

-The cracking pressure you're referring to is the reverse direction for the pilot operated check. I don't think that's relevant to anything you're doing because you're not running the POCk in reverse you are only using it open and closed in the direction to go to tank so it shouldn't matter what the cracking pressure is

-In a counter balance shown in the schematic the spring setting to control the load is the load pressure added to pilot ratio times the pilot pressure and it does take some calculation but I don't think you have that situation.
Using a POCk to try and control the load that needs a counterbalance would probably create instability and hammering but you don't have a gravity load over running you have a resistive load

-45 gallons a minute I would definitely use number 12 or number 16 ports and parts

-Dumping to tank without the filter should not be an issue. The purpose of a filter in the return line is for steady state cleaning up the fluid over a long period of time it's not intended to be a sudden trash stopper from a cylinder coming apart so fluid direct to tank under the surge conditions should not be an issue. It's also better on the filter media to not deal with surges

-Hoses and ports. the adage that the smallest port determines the flow and all the other hose sizes is not true. the resistance and pressure drop is the sum of all these items in series just like an electrical circuit. If you have a very small cylinder port but very large hoses and fittings The sum of all of the pressure drops could still be reasonably low. if you have a small restrictive port that doesn't mean you can get by with small hoses the rest of the circuit.

-Calculating the horsepower of a two-stage pump is easy enough. it's simply two pumps together. In low Pressure high flow condition it's the gallons per times the pressure times unit conversions. When the large gear set unloads the total horsepower is the small gear set flow times its higher pressure times unit conversions. then add the large gear set flow operating at maybe 50 psi unloading times unit conversions and the sum of those 2 hp is what the engine has to turn at the pump shaft

 

[SemperFiSawguy]

I have not read every reply in this thread so take this with the grain of salt

-A dump valve is not to increase speed, but it's to decrease pressure drop so that a large volume of flow does not have to go back through the spool valve. It allows using a smaller (much cheaper) spool valve and reduces pressure drop. Reduced pressure drop is reduced heat and fuel usage.

-Speed is flow which is determined by the fixed displacement pump. It's not going to change by using a dump valve. There might be some slight efficiency improvement by the components operating at a lower pressure but it's minuscule and probably measuring error.

-Pressure is a result of a resistance of a load, it is not 'created' by a pump. The load creates the resistance and the pressure required to move that load is what the pump has to turn against. If there's no resistance on the pump output there's very little pressure. I so often hear 'no pressure, must be the pump'. I'm talking about fixed displacement gear pump here not pressure compensated variable systems

-The sun valve that you show in your schematic is a pilot operated counterbalance valve. It's purpose in the schematic shown is to meter the flow and control the gravity load from running away when commanded down by the spool valve. A dump valve is usually a pilot operated check valve that is not intended as a metering device. it's intended to be more like a switch, just wide open or closed. Both of the sun cartridge styles will fit in the same cavity for that series.
A PO Ck will usually have lower pressure drop as it will be fully open. A counterbalance valve can create pressure drop and heat when it is metering, but be fully open sometimes, it depends on the circuit details.
What is unique about Sun is that they have their shoulder halfway down instead of at the very top end. Their advertising claim was that this put less mechanical stresses in the spool. Can't say. We used hundreds of sun valves they were great. The more common ISO cavity has locating shoulder at top, simply because it is dimensionally a standard o-ring port and tooling, just drilled deeper. Manufacturing reasons.

-The cracking pressure you're referring to is the reverse direction for the pilot operated check. I don't think that's relevant to anything you're doing because you're not running the POCk in reverse you are only using it open and closed in the direction to go to tank so it shouldn't matter what the cracking pressure is

-In a counter balance shown in the schematic the spring setting to control the load is the load pressure added to pilot ratio times the pilot pressure and it does take some calculation but I don't think you have that situation.
Using a POCk to try and control the load that needs a counterbalance would probably create instability and hammering but you don't have a gravity load over running you have a resistive load

-45 gallons a minute I would definitely use number 12 or number 16 ports and parts

-Dumping to tank without the filter should not be an issue. The purpose of a filter in the return line is for steady state cleaning up the fluid over a long period of time it's not intended to be a sudden trash stopper from a cylinder coming apart so fluid direct to tank under the surge conditions should not be an issue. It's also better on the filter media to not deal with surges

-Hoses and ports. the adage that the smallest port determines the flow and all the other hose sizes is not true. the resistance and pressure drop is the sum of all these items in series just like an electrical circuit. If you have a very small cylinder port but very large hoses and fittings The sum of all of the pressure drops could still be reasonably low. if you have a small restrictive port that doesn't mean you can get by with small hoses the rest of the circuit.

-Calculating the horsepower of a two-stage pump is easy enough. it's simply two pumps together. In low Pressure high flow condition it's the gallons per times the pressure times unit conversions. When the large gear set unloads the total horsepower is the small gear set flow times its higher pressure times unit conversions. then add the large gear set flow operating at maybe 50 psi unloading times unit conversions and the sum of those 2 hp is what the engine has to turn at the pump shaft

Very informative thank you for taking the time to type all that out. I have a feeling by tuesday i will have netted some new and positive results! Which i of course will post up here with plenty of pictures.

 

[sean donato]

Sean what say you on this pump? High pressure side is only 6.2gpm..?
28gpm is only ever on up until 900psi when it shifts? Its rated at 25gpm efficiency..
Are chief pumps chinese or reputable in quality? Check this one out. I see zero reason that cant be ran with a 13hp engine based on the math alone?

https://www.baileyhydraulics.com/Two-Stage-Pumps-Chief-8-09-CID-Rated-GPM-28/

Best I know they are a bailey's brand. I don't know if they are usa made or not.

 

[kevin j]

Very informative thank you for taking the time to type all that out. I have a feeling by tuesday i will have netted some new and positive results! Which i of course will post up here with plenty of pictures.

The blessings of voice dictation, although it's not too accurate and it does take a lot of typing to correct

 

[chipper1]

The blessings of voice dictation, although it's not too accurate and it does take a lot of typing to correct

That's funny.
I type 100 words a minute, unfortunately it takes me about 20min to fix all the mistakes lol.

 

[SemperFiSawguy]

Delivery is scheduled for tomorrow, i am very excited to get all of this plumbed in tomorrow and see what the results are. I wonder how i can compress a video to upload it? I had great success today, i picked up 36 IBC totes!! Going to be stripping them so i can put the splitter to work as soon as its put back together tomorrow.
Hopefully i can get enough stripped tomorrow to split the whole afternoon.

 

[chipper1]

Delivery is scheduled for tomorrow, i am very excited to get all of this plumbed in tomorrow and see what the results are. I wonder how i can compress a video to upload it? I had great success today, i picked up 36 IBC totes!! Going to be stripping them so i can put the splitter to work as soon as its put back together tomorrow.
Hopefully i can get enough stripped tomorrow to split the whole afternoon.

Nice score on the totes.
I upload larger videos to YouTube, then copy the url to the post. For smaller files I just recently started uploading them to the post from my phone.

 

[SemperFiSawguy]

Well gentlemen, it seems as though ive got it licked!! With warm oil my cycle time is at 7.75 seconds consistently which meets my goals!! I cleaned up the plumbing a bit. I have a couple more changes too do with the fittings directly off the control valves. I need to shorten that hose and change the lower barb to a 1x1 90° to clean that up better but the new T setup is much cleaner and works excellent. I switched out the check valve to the SUN CKEB and T2A cavity body and that seems to work much better. Eliminating the internal piston seems to have eliminate the leakage during the extend stroke through the check valve.

The only way i can speed it up anymore now would seem to be a pump change. Its entirely possible the current pump has a lower then advertised effiency and that is whats contributing to the slower speed in comparison to similarly equipped set ups. If i get a wild hair this spring sometime i may change that pump out. I will of course report back if i do and report my findings. For now, I've got about 20 chords i need to process and 36 totes i need to fill.. thank you too everyone who chimed in and assisted in the trouble shooting you guys rock!

 

[chipper1]

Well gentlemen, it seems as though ive got it licked!! With warm oil my cycle time is at 7.75 seconds consistently which meets my goals!! I cleaned up the plumbing a bit. I have a couple more changes too do with the fittings directly off the control valves. I need to shorten that hose and change the lower barb to a 1x1 90° to clean that up better but the new T setup is much cleaner and works excellent. I switched out the check valve to the SUN CKEB and T2A cavity body and that seems to work much better. Eliminating the internal piston seems to have eliminate the leakage during the extend stroke through the check valve.

The only way i can speed it up anymore now would seem to be a pump change. Its entirely possible the current pump has a lower then advertised effiency and that is whats contributing to the slower speed in comparison to similarly equipped set ups. If i get a wild hair this spring sometime i may change that pump out. I will of course report back if i do and report my findings. For now, I've got about 20 chords i need to process and 36 totes i need to fill.. thank you too everyone who chimed in and assisted in the trouble shooting you guys rock!

That's awesome.
How much of this unit did you build, I really want to build one myself that performs in that range. I have a 15 gallon tank, radiator with a fan, and two splitters to sell to help fund the build. Any thoughts or tips would be greatly appreciated .

Cords , chords .

 

[SemperFiSawguy]

That's awesome.
How much of this unit did you build, I really want to build one myself that performs in that range. I have a 15 gallon tank, radiator with a fan, and two splitters to sell to help fund the build. Any thoughts or tips would be greatly appreciated .

Cords , chords .

In all honesty? All i really ended up using was the pump, the valves and the main frame. I basically cut off and reworked almost everything. And i am going too have too it looks like replace the whole pushplate assembly as on really nasty stuff the slide guides are worn enough where it twists and snaps the measly 1/2 bolts off clean. Im going to machine some pieces out of 2 inch bar stock on my mill for the slide guides and then use a 3/4inch 9"x12" main plate for the lower slide and transfer my pushplate onto that new slide assembly. That should solve that. The assembly as it exists now seems to just be too loose and floppy and can turn too much on white oak. Ive sheared the bolts off twice. Even after added another bolt too each side. 1/2 bolts just arent enough to counteract that much shear force.

 

[sean donato]

Make sure your ahaft bottoms out on the back of the push plate and doesn't just rely on the bolt. Common mistake made. Mine has a 3/4" through bolt and I sheared it quite a bit before realizing my error.

 

[SemperFiSawguy]

When I machined the block for my new parts for the push plate I made sure the end of the cylinder rod contacts the 1 inch plate directly. The pin free floats under load and is only loaded during the retract stroke. A lesson I learned after building the splitter for my excavator.

Make sure your ahaft bottoms out on the back of the push plate and doesn't just rely on the bolt. Common mistake made. Mine has a 3/4" through bolt and I sheared it quite a bit before realizing my error.