How does a hydraulic ram make 180000 tons of force

[woodlandfarms]

Watching a video in the welding section (a video on how pressure tanks are made) and they use a ram that puts out amazing pressure. Not to be ignorant, but what kind of pump builds that kind of pressure and what kind of seals hold up under that pressure, heck, what kind of hoses survive that pressure. I must be missing something.

 

[davesl708]

Hydraulic forces are a function the size of the fluid entering the cylinder and the size of the cylinder in square inches. YouTube has good videos on the process. No seals are used at those pressures. It is the close fit of the ram an cylinder that contains the pressure.

 

[Ruger761]

I have a ram at work that I made for testing off shore equipment. It puts out 1.3M lbs of force. Has 169 in^2 piston at 7700 psi. Like Daves said all about the size of the cylinder and the pressure. This ram actually has very large O-rings for seals. Pump for it actually goes to 17,000 psi. Hoses are good to 15,000 psi. Not your standard off the shelf system by no means and doesn't move very quickly either.

 

[bigdeano]

When I watched the video they said 800 tons. Still a lot though.

 

[Leejohn]

You could do it with 2000psi, but I would hate to guess what size the bore would have to be.

 

[LD1]

Take the bore size of the cylinder.

Pi times r squared times hydraulic pressure (psi) equals force.

180,000t is 360,000,000 pounds of force.

With a 5000psi system, you would need the bore to have 72000 sq inches. Or a diameter of about 300" (25')

A little beyond belief... I think you tons and pounds confused or something, but certainly doable.

As said, seals contain the pressure. Which don't have to be any higher than a normal system. Size gets you the tonnage.

At work, we have a hydraulic press that has a 14" bore cylinder with a 120" stroke for making the halves of aluminum propane cylinders. (Forklift cylinders). At about 2600psi it makes around 200t. There are 3 pumps each driven by a 150hp motor. Each in the 70gpm range. So over 200 gpm flow. 2500 gallon resivoir and high pressure fed through 4" main lines.

Bigger is certainly not hard to imagine. Just scale things up. Look at the size of some of the big construction equipment

 

[Texasmark]

You could do it with 2000psi, but I would hate to guess what size the bore would have to be.

Do the math. Piston area is ½ the diameter squared (d/2 x d/2) x pi (22/7 or 3.1417XXXXXXX) x pressure in pounds per square inch yields pounds of force.

180,000 tons is 3.6x exp8 (natural logs) = 2500 psig (for a number for pressure in psig) x area of piston.

Transposing, area of piston = 18000 tons/2500 = 1.44 exp5.

Diving by pi 1.44 exp5/3.14 = ½ dia squared (radius squared) = 4.6 exp4 inches (since values are in #/ in squared).

Solving for the diameter in inches = square root of 4.6 exp4 = 2141 x 2 = 4283/12 = a diameter of 35'.

,,,,,,,,nothing else to do this evening :cool2:

 

[CalG]

Do it the other way.

Press 2000# against a very small area and the loading in PSI can be very large indeed. There is reason that fine mechanical watch movements used jewels. HIGH loads on those tiny pivots.

But for the sake of the hydroforming example, The "tonnage" can be high if there are lots of square inches in play.

180,000 tons is a meaningless number. The air we live in exerts that much over any (do the math here) area of the earth's surface.

 

[npalen]

Lets see--180,000 tons of force equals 360 million pounds of force. Thats a lot of cheeseburgers!

 

[SPYDERLK]

Take the bore size of the cylinder.

Pi times r squared times hydraulic pressure (psi) equals force.

180,000t is 360,000,000 pounds of force.

With a 5000psi system, you would need the bore to have 72000 sq inches. Or a diameter of about 300" (25')

A little beyond belief... I think you tons and pounds confused or something, but certainly doable.

As said, seals contain the pressure. Which don't have to be any higher than a normal system. Size gets you the tonnage.

At work, we have a hydraulic press that has a 14" bore cylinder with a 120" stroke for making the halves of aluminum propane cylinders. (Forklift cylinders). At about 2600psi it makes around 200t. There are 3 pumps each driven by a 150hp motor. Each in the 70gpm range. So over 200 gpm flow. 2500 gallon resivoir and high pressure fed through 4" main lines.

Bigger is certainly not hard to imagine. Just scale things up. Look at the size of some of the big construction equipment

Do the math. Piston area is ｽ the diameter squared (d/2 x d/2) x pi (22/7 or 3.1417XXXXXXX) x pressure in pounds per square inch yields pounds of force.

180,000 tons is 3.6x exp8 (natural logs) = 2500 psig (for a number for pressure in psig) x area of piston.

Transposing, area of piston = 18000 tons/2500 = 1.44 exp5.

Diving by pi 1.44 exp5/3.14 = ｽ dia squared (radius squared) = 4.6 exp4 inches (since values are in #/ in squared).

Solving for the diameter in inches = square root of 4.6 exp4 = 2141 x 2 = 4283/12 = a diameter of 35'.

,,,,,,,,nothing else to do this evening :cool2:

Lets see somebody find a cylindrical pressure vessel tens of feet in diameter that will withstand several kpsi internal pressure.

 

[Leejohn]

What size pins would be needed?

 

[IceStationZebra]

Power density is one of the benefits of hydraulics. At work we get large instrumented pins made thru a supplier, which are then sent to Lehigh University to perform the calibrations on their 5,000,000 lbs universal tester. http://library.lehigh.edu/omeka/exhibits/show/jfl/butm/tm

If you want an interesting read google "heavy press program." Part of the program included the construction of two 50,000 ton presses. The Mesta/Alcoa press was totally rebuilt a couple years back and there are some good articles on it. It only operates at 4500psi by the way. History in the Making
https://www.asme.org/wwwasmeorg/med...1-ALCOA-50000-ton-Hydraulic-Forging-Press.pdf

ISZ

 

[bcp]

This video on making pressure tanks says "up to 800 tons" at about 1:06 into it.

https://www.youtube.com/watch?v=Z0L9BO02cZs

Bruce

 

[smilinjak]

Do the math. Piston area is ｽ the diameter squared (d/2 x d/2) x pi (22/7 or 3.1417XXXXXXX) x pressure in pounds per square inch yields pounds of force.

180,000 tons is 3.6x exp8 (natural logs) = 2500 psig (for a number for pressure in psig) x area of piston.

Transposing, area of piston = 18000 tons/2500 = 1.44 exp5.

Diving by pi 1.44 exp5/3.14 = ｽ dia squared (radius squared) = 4.6 exp4 inches (since values are in #/ in squared).

Solving for the diameter in inches = square root of 4.6 exp4 = 2141 x 2 = 4283/12 = a diameter of 35'.

,,,,,,,,nothing else to do this evening :cool2:

I understand all the math, can do it in my head, not. The DIVING by Pi has me a bit confused, swan, jack knife ,,, what kind do you recommend ?
Smilinjak

 

[npalen]

Interesting stuff for sure!

 

[woodlandfarms]

yeah guys, sorry, on the tonnage. but in the end 8000 800 80 it still blows my mind so little (in my head) can do so much. Thanks for all the insight and links, lots of reading for sure.

 

[SPYDERLK]

yeah guys, sorry, on the tonnage. but in the end 8000 800 80 it still blows my mind so little (in my head) can do so much. Thanks for all the insight and links, lots of reading for sure.

Yes, the huge forces are mind boggling, but with hydraulics it comes down to area and pressure and special contrivances to bring them to bear. The high forces, even in the 100s of tons rely on use of multiple cyls applied in pull mode driving a guided platen. In the thousands of tons this becomes the only way physically possible within the strength of materials.

 

[Texasmark]

I understand all the math, can do it in my head, not. The DIVING by Pi has me a bit confused, swan, jack knife ,,, what kind do you recommend ?
Smilinjak

Since area of the piston surface is defined as radius squared x pi, if you are looking for the diameter (aka 2x radius) you have to get the pi out of the area and multiply the radius by the 2.

 

[k0ua]

Pie? did someone offer pie?... I like most any kind..:laughing: I think someone said something about pie are square... but most I have seen are round?:confused3: I know this much about an 800 ton press... It sure as heck would squish your finger real good..

And diving by pie? I have been know to dive into a pie or two in in my time... and I have the gut to prove it!

 

[Furu]

You want to blow your mind. Look at the force that is translated by women in their daily walk-abouts in the fashion industry.
Calculate the PSI of the 3/8 inch diameter spike high heels that women wear that is translated to the surface they walk on. Especially if they rock/shift their weight back.