Just thinking outloud about splitters.

[jerseydevil]

How come Northern sells a 30 ton machine with a 5.5 hp engine, when most of the 27+ ton machines I see have an 8+hp engine? I guess if they sell it, it works right? Well, does that mean I can put a5 or 6 hp engine on my 33 ton splitter? Of course I can, but will it lack power? I doubt I would ever need 33 tons of force anyway. I am just thinking aloud and I welcome any thoughts.

 

[btlook1]

Northern splitters

Hey I bought a northern splitter about 10yrs ago. I think it's got a 6hp motor on it...might be a 5 but I'm to lazy to walk up on the hill and see for sure. Never had a problem with it except for needing a tune up and replacing a couple of hoses once....I don't pull it around much usually just sits by the pile...Seems to be when I did pull it around I had more problems with it.. I guess pulling it down the road is kinda hard on it. Seems like the vibration and stuff rattles it around pretty good. I would not have a problem buying another one from them. Good luck!

 

[046]

ignore tonage ratings...

go by HP of motor, GPM of pump, size of ram and cycle times

 

[triptester]

Most 2-stage pumps are capable of producing 3000 psi. Tonnage produced is a total of max pump pressure times size of the bore of the cylinder.
A 5.5 hp. motor with a 11 gpm pump and 5 inch bore cylinder =aprox. 30 ton.
A 8 hp. motor with a 16 gpm pump and a 5 inch bore cylinder = aprox.30 ton.
The 16 gpm pump will move the cylinder faster.

The type and gpm of the pump determine what size motor is required.

 

[CylinderService]

I guess if they sell it, it works right?

I had a VW bug once with a speedometer that went up to 110 MPH I think. I only drove it 80 for 5 hrs straight every other weekend to see a girl in Ohio. Sadly, the VW didn't last long.
Don't believe the labels. Listen to 046, triptester - pressure x piston area = force. No matter what they say, the marketers have no control over the laws of physics.
By the way, I've been married to that girl for 35 years, so my VW died for a good cause!

Don the Hydraulics Guy

 

[BlueRidgeMark]

Most 2-stage pumps are capable of producing 3000 psi. Tonnage produced is a total of max pump pressure times size of the bore of the cylinder.
A 5.5 hp. motor with a 11 gpm pump and 5 inch bore cylinder =aprox. 30 ton.
A 8 hp. motor with a 16 gpm pump and a 5 inch bore cylinder = aprox.30 ton.
The 16 gpm pump will move the cylinder faster.

The type and gpm of the pump determine what size motor is required.

Note that the advertised tonnage ratings are probably based on the MAXIMUM pressure for the system, NOT the working pressure. So, if it says 30 tons, you aren't getting 30 tons to the wood.

For example, take triptester's numbers above: a 5 inch bore @ 3000 PSI gets you 30 tons of advertised pressure. (29.452, for those who want to be picky.)

At a working pressure of, say, 2250 PSI, you get 22 tons of working pressure.

Okay, 22.089.

Drop that down to 2000 PSI, and you only get 19.635.

 

[drmiller100]

folks, this ain't that complicated.
all the hydraulic wood splitter pumps run to 3000 psi.

if you run a 30 ton ram at 10 horsepowr, it will be reasonably fast. if you run at 5 horsepower, it will be half as fast.

the larger the diameter of ram, the more tonnage, and the slower it moves.

 

[CylinderService]

Technically true. As long as you change pumps when you change engines. And while most logsplitter pumps are capable of 3000 PSI, most of the valves and many of the cylinders used are not rated that high. Not to mention hoses & fittings.
But you've probably found, if you've ever checked with a pressure gauge, most wood splitting can be done at much lower pressure. I usually recommend trying it with the relief set at 2000 PSI, and increasing the setting if you find you need to. Every time your cylinder gets to the end of its stroke, the pressure probably spikes to the relief setting, so keeping it lower makes everything last longer.
Which was the point of my VW story.

Don

 

[Steve128]

Service life

Technically true. As long as you change pumps when you change engines. And while most logsplitter pumps are capable of 3000 PSI, most of the valves and many of the cylinders used are not rated that high. Not to mention hoses & fittings.
But you've probably found, if you've ever checked with a pressure gauge, most wood splitting can be done at much lower pressure. I usually recommend trying it with the relief set at 2000 PSI, and increasing the setting if you find you need to. Every time your cylinder gets to the end of its stroke, the pressure probably spikes to the relief setting, so keeping it lower makes everything last longer.
Which was the point of my VW story.

Don

Don:

Would running the engine at 3/4 speed have the same effect as lowering the relief? Less noise and the speed is still fine for me. And if not, how does one go about to lower the relief settings?

thanks,

steve

 

[Butch(OH)]

Pressure x speed = HP required.

This equation cannot be changed with paint schemes, backyard engineering or wishful thinking. However advertising lore can gloss over the deficiencies in a cost saving design. Such as, A splitter with higher tonnage and lower HP input MUST be slower in cycle times. So advertise the tonnage in big print and don't talk about cycle times. As for max pressures being bad, that depends of the quality of the components which of course goes down as price goes down on comparable machinery.

 

[Butch(OH)]

A two speed pump considerably changes the equation.

Actually it does not, that is why the ram slows down when it meets resistance
Have you ever been around a splitter with enough nuts to run a single stage pump? Mine splits knots as fast as empty travel, the math still applies

Actually I made the assumption that any splitter powered by an overgrown lawn mower motor would have a two stage pump, otherwise they would have to be be dead slow or of so little force they couldn't split twigs thus he can still make use of the formula. I am trying to help him overcome the notion that it takes high HP to have high force when it does not. It does however take higher HP to have X force and pick up some speed.

 

[drmiller100]

It does however take higher HP to have X force and pick up some speed.

unless of course you are using a 2 stage pump......

 

[CylinderService]

Don:

Would running the engine at 3/4 speed have the same effect as lowering the relief? Less noise and the speed is still fine for me. And if not, how does one go about to lower the relief settings?

thanks,

steve

To answer Steve's question, slowing the engine speed will slow down the hydraulic flow (GPM, which determines cylinder speed), but it will NOT affect the ultimate pressure, PSI, which determines cylinder force. The relief on most systems is on the directional control valve, just to the left of where the handle attaches to the spool end. Remove the cap nut, and back out the screw to decrease the pressure setting. The relief allows the oil to bypass directly from the inlet to the return core when the oil pressure is strong enough to overcome the spring compression. Lower spring compression = lower bypass pressure. If there is an adjustment on your pump, it is the bypass pressure for the low pressure (high speed) pump. There is not likely a high pressure relief on the pump. If you want to install a pressure gauge, it should go next to the valve inlet, in the line coming from the pump.
As for higher pressure components, I've seen some splitters with advertised capacities dependent on pressures as high as 3500 PSI. While some pumps may be optimistically rated that high, I don't think any of the other system components are rated over 3000, and very likely at least some parts less than that. System pressure should never be rated higher than the lowest capacity component.
But if you're selling splitters, and you figure your customers are making their buying decision based on tonnage claims, you might choose to ignore that last part...

Don

 

[Steve128]

Answer

To answer Steve's question, slowing the engine speed will slow down the hydraulic flow (GPM, which determines cylinder speed), but it will NOT affect the ultimate pressure, PSI, which determines cylinder force. The relief on most systems is on the directional control valve, just to the left of where the handle attaches to the spool end. Remove the cap nut, and back out the screw to decrease the pressure setting. The relief allows the oil to bypass directly from the inlet to the return core when the oil pressure is strong enough to overcome the spring compression. Lower spring compression = lower bypass pressure. If there is an adjustment on your pump, it is the bypass pressure for the low pressure (high speed) pump. There is not likely a high pressure relief on the pump. If you want to install a pressure gauge, it should go next to the valve inlet, in the line coming from the pump.
As for higher pressure components, I've seen some splitters with advertised capacities dependent on pressures as high as 3500 PSI. While some pumps may be optimistically rated that high, I don't think any of the other system components are rated over 3000, and very likely at least some parts less than that. System pressure should never be rated higher than the lowest capacity component.
But if you're selling splitters, and you figure your customers are making their buying decision based on tonnage claims, you might choose to ignore that last part...

Don

Thank you Don.:biggrinbounce2: