Measuring hydraulic force

[Charles in Aus.]

I would like to confirm the claims that the wood splitter I've just bought has 14 tonnes of force . Rather than hydraulic pressure it is the power developed by the ram I need to measure .
Is there a straightforward way of doing this I could try ? Either mechanically by direct method or theoretically by calculation .
I suspect that they are over inflating capacity , either this or calculating the ram power against the thin edge of the splitting wedge .

 

[Fawteen]

If you know the max pressure of the pump and the size of the piston in the cylinder, it's simple math: Pump PSI times Area of Cylinder.

Example: 2500 PSI at the pump, 2.5 inch cylinder. Area of the piston is Pi x radius squared or 3.14 x 1.5625 or (rounded off) 5 square inches, times 2500 = 12,500 pounds. Divide that by 2000 to get tons or 6.25 tons.

EDIT to correct formula (Thanks, Daniel)

 

[DanielW]

Pressure X cylinder area = force. Cylinder area = pi*r^2.

For instance, if you're supplying 2000 psi to a 3" cylinder, force = 2000 x pi x 1.5^2 = 14,136 lb = 7 tons

 

[DanielW]

If you know the max pressure of the pump and the size of the piston in the cylinder, it's simple math: Pump PSI times Area of Cylinder.

Example: 2500 PSI at the pump, 2.5 inch cylinder. Area of the piston is Pi (3.14) times the diameter or 3.14 x 2.5 = 7.85 square inches, times 2500 = 19,625 pounds. Divide that by 2000 to get tons or 9.8 tons.

Not quite. Area of the cylinder is pi *r^2 [or (pi * D^2)/4].

Pi * D is circumference, not area.

 

[Fawteen]

You are correct, of course. Dang it...

Not enough coffee yet.

 

[Charles in Aus.]

Brilliant , thank you all

Its late Sunday evening here at the moment
A project for Monday , that is if the cold let's me .

 

[MarkB_MI]

I think the best way would be to measure the hydraulic pressure with a gauge, then use that to calculate the force. 100 percent of the fluid pressure will be converted to linear force, which you calculate by multiplying the pressure times the cross-sectional area of the cylinder.

In order to directly measure the linear force you would need some sort of load cell, and load cells that can measure 14 metric tons are not cheap.

Back in the day there was a local mechanic named George. A farmer didn't think the hydraulics on his tractor were working right, so he asked George to check it out. George says, "no problem", unscrews the high pressure gauge off his torch's oxygen regulator and plumbed it up to the tractor's hydraulics. And it turns out the hydraulic pressure on the tractor was just fine. Of course, the next time he went to use his torch the gauge 'sploded in his face. Fortunately George escaped serious injury. So don't use the O2 gauge off your oxyacetylene rig.

 

[jniolon]

maybe it was upside down because you're inn Australia ??

 

[Charles in Aus.]

maybe it was upside down because you're inn Australia ??

The forum does this automatically whenever I post a photograph. I always thought it was aa act of courtesy , acknowledging our country

 

[Tony in SD]

I think the best way would be to measure the hydraulic pressure with a gauge, then use that to calculate the force. 100 percent of the fluid pressure will be converted to linear force, which you calculate by multiplying the pressure times the cross-sectional area of the cylinder.

In order to directly measure the linear force you would need some sort of load cell, and load cells that can measure 14 metric tons are not cheap.

Back in the day there was a local mechanic named George. A farmer didn't think the hydraulics on his tractor were working right, so he asked George to check it out. George says, "no problem", unscrews the high pressure gauge off his torch's oxygen regulator and plumbed it up to the tractor's hydraulics. And it turns out the hydraulic pressure on the tractor was just fine. Of course, the next time he went to use his torch the gauge 'sploded in his face. Fortunately George escaped serious injury. So don't use the O2 gauge off your oxyacetylene rig.

I could see where you were going with that as soon as you said he took the gauge off the O2 regulator. We learned about that in high school shop class about the time dad bought his first cutting torch. The regulator was turning hard onto the O2 tank so dad grabbed the oil can. I stopped him and told him what would happen if oil and compressed O2 met. He told me to get out of the way because I was just a kid and didnt know what I was taking about. I would not let him get the oil near the O2 tank. He finally believed me when I said, "How does a diesel engine work?" That was the first time I stood up to my dad because I knew I was right and if I didn't, we both may have been gone that day.

 

[joeysmith]

There are a few pictures around of people using oxygen to pressure test an ac system with oxygen instead of nitrogen
Some of them didn't get a chance to do it again

 

[Russ from MN]

Remember there are 2204.6 pounds to a metric ton! But your cylinder is probably measured in mm, your pressure in bars, so it will all be metric.

 

[Destroked 450]

Very informative book pertaining to this subject
I’ve had this one for many years

 

[Ozlander]

I think you need to measure the pressure instead of assuming the pump output pressure.

 

[Charles in Aus.]

No specifications listed on the pump at all . The only information on the splitter itself is the 2200W rating of the electric motor .
The distributor is going to ask the manufacturer for the specifications, if i get these i will report back .

 

[560Dennis]

Put a load cell on it if your handy .we have them in our high presses attached to the columns , stopping that baby on a dime (actually better) at 200 strokes a minute , , Got to have it, the money we’re talking about losing making muti hits on our dies sets.