estimated cycle times (log splitter)

[moose13]

Hey all, i am waiting on my cylinder but will start some fabrication tomorrow on a log splitter. I was curious on how to calculate cycle times?

I have a 6.5 hp Honda, 13.6 gpm pump, and a 4"x24" stroke cylinder.
I know i could just wait till its done and try it, but was wondering what my cycle times might be.

Thanks!
Moose13

 

[beenthere]

My guess, is 12 seconds.

But to calculate, roughly 302 cu. in in the 24" cylinder filled (may be a bit less). There are 1.3 gal of liquid in 302 cu in. 13.6 gpm converts to 0.2266 gal per sec. Divide the 1.3 gal by the 0.2266 gps and get 5.74 seconds to extend. May be faster on the return, so may be closer to 11 seconds total cycle time. The guess was close.

 

[moose13]

Very nice! Thank You:thumbsup:
I was hoping for somewhere right in there.

Moose13

 

[Scooby074]

Speed for a Hydraulic Cylinder - Calculates Extended Speed, Retracted Speed, Extend Time, Retract Time, Cycle Time

Around 10.5 depending on rod dia.

 

[moose13]

Thanks Scooby!

 

[trailbuilder]

my guess is 14 seconds.

 

[AKKAMAAN]

A Haldex-Barnes13 gpm pump? Or a knock off 13.6 gpm??

A 13.6 gpm cycle a 4x2x24" at about 10 sec...

I got a "treat" for you!

Online spread sheet...Haldex-Barnes two stage pumps

Spread sheet can be down loaded to your own computer as Excel or OpenOffice file. Then you can edit numbers as you want...keep this link for recovery, if formulas get lost....

Only numbers in the Green cells are subject to change.

Play with pressure setting numbers to see how horse power requirement changes

Pump displacements and max allowed pump speed and pressure, is copied from Haldex-Barnes info PDF file

Note that all flow numbers are based on a 3600rpm pump speed.

 

[moose13]

Cool!
Yes it is a Haldex 13.6 gpm.
I started fabricating the splitter today i will update with pictures.

 

[oldnslo]

formula to figure cylinder velocity is:

Q=VA

Q= flow rate
V= Cylinder Velocity
A= Area of cylinder in square inches

 

[AKKAMAAN]

Cool!
Yes it is a Haldex 13.6 gpm.
I started fabricating the splitter today i will update with pictures.

Just curious....
I do not know how you got that "13.6"-number??Do you have "some mouth to mouth" information, or some facts that can be backed up, that I have missed. Maybe a discontinued pump model?

Haldex-Barnes pump with nominal flow 13 gpm, flows 13.11 gpm at 3600 rpm.
Math:
displacement on the two pump units are 0.194+0.647=0.841 cui.
Out put flow will then be 0.841 x 3600=3,027.6 cui/min>>3,027.6/231=13.11 gpm

That is the theoretical flow, which will be reduced when internal leakage gets counted into the equation. Volumetric efficiency is not posted in the H&B pdf, can be expected to be between 85-95% with a 300SSU/57cSt viscosity oil and at operating pressure.

Since high flow is at a lower pressure, I would "guesstimate" eff to 95%, and actual high flow would then be about 13.11 x 0.95 = 12.5 gpm....

Not a big deal, but with wrong impression of real flow, it is easy to make a call for a bad pump....