Hydraulic pump and valve question

S

Swamphunter1968

Joined
May 24, 2021
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I am building James Keeton's press, even using all the components he has recommended, but just have a couple quick questions. I have been reading posts and researching for days, I've also searched all the previous threads, but I'm either just not finding or completely understanding the information I'm reading. I spoke to James a couple times, and he is VERY helpful and nice, but I don't want to pester the guy. :-)

I am using a 3000psi, 5" bore, 8" stroke, 2" shaft cylinder

Pump question - I see James uses an 11gpm pump, (because he already owned it) but in his video he states he may want to increase that in the future. What would be the difference if say... going from the 11gpm to a 13gpm pump, or even higher?

Valve question - What is the difference between a spring assist valve and a detent valve, and 3 way vs 4 way? Am I correct in thinking the spring assist handle returns to neutral immediately, and the cylinder stops and stays where it is when the handle is released versus a detent returning to neutral once a certain psi is reached? Or are they the same and I am overthinking it?

Please go easy on a feller...., hydraulics is all new to me.
 
Have you read this thread: https://www.bladeforums.com/threads/forging-press-opinions-wanted.1956336/
That thread has some discussion of control valves. It seems the typical log splitter valve is what you want for a press. Press and log splitter seem to have similar requirements for control valve. Open center so oil can recirculate, and spring return to center position. There are times when you don't want full pressure, such as when setting a weld.

Have you looked at these two on-line calculators?
Hydraulic Cylinder Calculator
and for speed (you can play with different gpm pumps to see the difference in speeds.)
Hydraulic Cylinder Speed Calculator
and for motor size: (you planning a 5hp motor for 25 ton?) Remember, when calculating the hp required to use the pump high pressure flow, NOT the low pressure flow. For one pump I see specs on it is a 16/3.5 GPM pump. My understanding is it pumps 16gpm at 3600 RPM until pressure reaches 650psi then switches to 3.5 GPM for high pressure up to 3,000 psi max. That's the 2 stage type pump.
 
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Thank you....Yes, 5hp motor 3450rpm. I've used the calculators as well and I think everything is where I need it to be, for safety and my application. I'm just trying to learn the ins and outs of the pump and the valve.
 
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