Hydraulic port size/flow question

[dbchaplin03]

I built a pretty substantial log splitter about 8 years ago that is very similar in spec to what a lot of commercial splitters are. I'm trying to drop the cylinder from a 5" down to a 3.5" to at least double the speed of the cycle.

I have a 22gpm 2 stage pump and 3/4" NPT hoses from the autocycle valve to the current 5" cylinder. All the 3.5" cylinders I've found have a max of 1/2" NPT fittings. I know i can cut them off and weld on 3/4" but I hate to do that to a brand new cylinder unless I have to.

I've done a bunch of searching and can't find solid information on whether or not a 1/2" NPT fitting would flow my 22gpm fluid or not. I'd prefer to use a 1/2" to 3/4" NPT adapter for ease vs cutting them off and rewelding. I know it could cause some heat but I have 30 gallon tank that has never gotten even remotely hot so I'm not sure how big of an issue that would be. Any advise or feedback would be appreciated.

 

[oldnslo]

Per my reference handbook a schedule 40 1/2” pipe will flow 23 GPM at 25 feet per second so yes it would handle that flow but will most likely become turbulent especially if there is an elbow used. You will have estimated 20% more flow from blind end when retracting but not doing any work then.

You will be reducing the splitting force by approx half also.

 

[dbchaplin03]

Per my reference handbook a schedule 40 1/2” pipe will flow 23 GPM at 25 feet per second so yes it would handle that flow but will most likely become turbulent especially if there is an elbow used. You will have estimated 20% more flow from blind end when retracting but not doing any work then.

You will be reducing the splitting force by approx half also.

The reduction in splitting force you are talking about is simply because of the smaller diameter cylinder and not the ports though, right?

I’m ok with less force if I can get a 2-3x faster stroke. Many commercial splitters have a 3.5”’cylinder machine because speed is the name of the game these days. I do 10x more 12-18” wood than I do big nasty stuff so I’m confident the 3.5” will be more than sufficient in terms of force especially if I use my 2 way wedge instead of the 4 way.

Thanks for your help, I really appreciate the information you shared

 

[oldnslo]

Yes loss of force is due to cylinder size since when the two stage pump shifts your flow will drop by 60 - 70%.

Example: 22 GPM at 800 PSI = approx 11.75 HP input

Low flow of 7 GPM at 2,500 PSI = approx 11.6 HP input

 

[hayden]

Another way to speed it up would be switch to a bigger pump. I don't know how the costs compare, but that way you could increase speed without reducing splitting force.

 

[oldnslo]

The big unknown is how fast do you want the cylinder to extend? If my math is correct 22 GPM will extend a 5” cylinder at rate of approx 300 inches per minute or 5” per second. To me that seems fast enough but I also am not splitting any serious amounts of wood.