Hydraulics for a press

[BigChevy17]

So I'm building a hydraulic press and have no issues with the frame but the hydraulics are making me scratch my head.
I'm thinking about a 5" flange mount cylinder.
My question is about the pump, will a 2 stage log splitter pump like this be enough for this size cylinder?

http://m.northerntool.com/mt/www.northerntool.com/shop/tools/product_200321055_200321055

This pump calls for a 8hp gas engine but says nothing about an electric motor, what size electric motor would suffice for running this pump?
Thanks

 

[J king]

Just have been dealing with this on my car lift I'm building .you need to do a google search on pressure,gpm,hp and ram size.
Here is one link. http://www.calcunation.com/calculat...calc=yes&Calculate=Calculate+Input+Horsepower

You need to decide on the tonnage you want and then the size cylinder.figure the psi and then the pump and finally the size motor to achieve this.

My guess is a log splitter pump isn't going to get it.Too high of flow rate.look at the calculator and see unless you have a huge electric motor.

I had a 5 hp motor running a 2.5 gpm pump and had to halve the pump displacement and increase the pressure output.Now I will be able to launch the car and also run my press with the same hydraulic unit.I am going to put a hydraulic quick connect on the unit and one on the lift and press.Should work good.

 

[J king]

How many tons pressure do you want for the press.

 

[BigChevy17]

I'm shooting for 20-30 tons, a 5" cylinder with a 2" ram at 3000 psi should put me there at 25 tons. Not sure if that's a common size cylinder but that's just what messing around with a calculator got me.

 

[Schleprock]

Rule of thumb;

For every 1GPM @ 1500PSI = 1HP

 

[BigChevy17]

So this pump with a 2hp 2000rpm motor should give me 3190 psi, right?

http://www.surpluscenter.com/Hydrau...cu-in-DYNAMIC-GPF1034PA-HYD-PUMP-9-7765-D.axd

 

[J king]

Here's is another link.

http://www.surpluscenter.com/Tech-Help/Hydraulics/Calculators/Pump-Disp-HP/

If you want 3000 psi you can run a .1 cu.in pump at 1750 rpm with a 2 hp electric motor and have 1 gal a minute flow.

 

[Schleprock]

Nope you're under powered.

1800rpm is standard for an electric motor so;

1800 x .2 cu in / 231 = 1.56 GPM

1.56 GPM @ 3190 PSI = 2.9 HP

 

[J king]

You doubled the pumps output ..

 

[bigfunwmu]

Stay away from a log splitter pumps for a shop press. You will have to deal with unpredictable movement speeds when trying to move stuff under load.

There are some plug & play 110 VAC power units that can do what you want to do, or you can build one yourself.

A little electric motor with c-face mount, one of these: http://www.lovejoy-inc.com/products/hydraulics/pumps-motor-mounts.aspx a small hydraulic pump, a tank and a single spool lever operated valve and you can be off and running.

A 1 gallon per minute pump will move your 5" ram about 11 3/4 inches per minute. Higher flow will give higher speed but take more HP when you go to push hard. The math to get your gallons per minute for a pump is: [Pump size in cubic inches X RPM] / 231 = GPM If all you have is CCs then divide them by 16.4 to get cubic inches.

We run 2 presses with the same power unit. One has a very large cylinder for pushing big stuff and it goes very slowly. The other one has a little cylinder and runs much faster, works great for pressing bearings onto shafts and other quick and easy stuff. We have a couple QD fittings we swap over so we only can run press at a time (safety and stuff).

 

[BigChevy17]

So a 3hp 1800 rpm motor with the pump I posted before would give me 3190 psi at 1.56 gpm?

 

[bigfunwmu]

So a 3hp 1800 rpm motor with the pump I posted before would give me 3190 psi at 1.56 gpm?

Yes.

You will need a control valve with a relief in it that can be set to your pressure setting though. Many of them are limited to 3000 PSI.

(assume slightly lower flow since most pumps are not 100% efficient, plan for about 90% flow)

ETA: still use the full flow to calculate needed input HP though

 

[J king]

Sorry Bigfun.. Thought you were replying to my post.

 

[bigfunwmu]

Sorry Bigfun.. Thought you were replying to my post.

You guys had a lot to say between when I started typing that and when it showed up!

 

[BigChevy17]

Thanks for all the replies.
I think I have the pump figured out, do you think 1-1.5 gpm will be enough? I don't want to wait for the ram all day but I want to have good control when it's under load.

 

[A_Pmech]

Thanks for all the replies.
I think I have the pump figured out, do you think 1-1.5 gpm will be enough? I don't want to wait for the ram all day but I want to have good control when it's under load.

There are 231 cubic inches to a gallon. 1.5 gpm would be 231*1.5=347 cubic inches of oil per minute. Assuming a 5" cylinder, 347 cubic inches of swept volume = 17.7 inches of ram travel per minute.

Control is achieved though valving. The easiest way to do this is to use a rotary spool valve. It allows much more sensitive control of the fluid flow rate.

 

[BigChevy17]

There are 231 cubic inches to a gallon. 1.5 gpm would be 231*1.5=347 cubic inches of oil per minute. Assuming a 5" cylinder, 347 cubic inches of swept volume = 17.7 inches of ram travel per minute.

Control is achieved though valving. The easiest way to do this is to use a rotary spool valve. It allows much more sensitive control of the fluid flow rate.

This place is awesome, thanks!

 

[BigChevy17]

Could I get some input on this cylinder?
This is the only thing I can find so far that fits my needs assuming that the clevis mount on the ram comes off so I can have a threaded ram.
http://m.ebay.com/itm/190907078755?nav=SEARCH