hydraulic help?

[bluebobtail]

Hi i have a log splitter which i'm running off a hydraulic power pack.
It seems a little under powered and struggles to split some wood.
Does anyone know how to work out the force the ram is putting out.

Just not sure if its down to the ram or the power pack.

The pack i have is like this one i believe.
Details

Fuel Petrol
Power kW (hp) 4.1 (5.5)
EHTMA category C
Hydraulic flow 20l/min @ 69 bar

Ram size is 85mm dia
Stroke 330 mm
Rod dia 40 mm
Thanks
Ian

 

[brightspark]

a presure gauge in the line would be a good start

 

[Paul.]

Theoretical force on the big end of the piston not allowing for any mechanical losses is about 3.9 tons

 

[bluebobtail]

Can i fit one to the lever valve?
I'll try and get a photo of it

 

[bluebobtail]

Thanks tigpaul, Thats not a great deal then.
No wonder she struggles a bit.

 

[bluebobtail]

So is it the engine and pump that is lacking the guts or the ram?

 

[Paul.]

You could fit a bigger diameter ram to get 69 bar (about 1007psi) pushing on a bigger area, it would move slower though and move more oil, or you could increase the pressure supplied to the existing ram, 69 bar isn't really very high in hydraulic terms,

 

[bluebobtail]

I think the power pack needs to be better then from what your saying. I'm limited with the power pack as it runs a hydraulic breaker.
http://www.tchjcb.com/new-jcb/new-jcb-machines/hydraulic-power-packs
That is a newer version of mine.

 

[dai]

normally tractors run about 200 bar pressure

 

[Luke]

Theoretical force on the big end of the piston not allowing for any mechanical losses is about 3.9 tons

Just put the numbers in to excel (got the formula wrong the first time), assuming 85mm piston dia, a force of 3995 Kg. If that's the outside dia of the cylinder itself, the force will be less.
75mm (allowing for 5mm wall) would be 3110 Kg.

 

[Paul.]

Converted back to imperial
area of piston is 8.79 sq inches
69 bar = 1000 psi for round figures
1000 psi pushing on 8.79 sq" = 8790 pounds force
2240 pounds to the ton so 8790 divided by 2240 = 3.92 tons
I know there are other factors to consider but just a rough calc

 

[bluebobtail]

More power needed then.
I'll have to start looking around the scrap yard to see what i can find!!

Thanks everybody

 

[Ian D]

Intresting read. I will be having a bash at making a kindling splitter soon for splitting 2x2 3x2 3x3 etc.
Have seen a blade design that i like on utube just need to scale it down.

 

[bluebobtail]

Hi, mine pushes the wood on to the bleade,blade been stationery. It works well apart from been under powered. It sometimes struggles on logs without knots. Which can make it hard work.
I have access to a old jcb so may use that for the power, but will see what I can find

 

[dai]

you could always make a mechanical 1
http://www.youtube.com/watch?v=IAddyGNZ1cQ
http://www.youtube.com/watch?v=vmtMv7Cz0HA&feature=related
http://www.youtube.com/watch?v=2bVAAx3mMKY&feature=fvwrel

 

[bluebobtail]

They look a little dangerous to me. An accident waiting to happen me thinks

 

[bluebobtail]

They look a little dangerous to me. An accident waiting to happen me thinks

 

[Justme]

Dont forget that on the out stroke the piston area has the shaft in it so will be about 30% smaller then the return stroke.

As has been said you can trade speed for power. Your flow rate is good (have you used large pipes & controllers? If not your flow will be low as well.

 

[bluebobtail]

It has large pipes coming from the power pack reducing down at the control valve, staying small to the ram. Not sure on sizes will check tonight if its not raining.
I don't really want to run it slower as it will just take to long to split the wood.