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If 2 hyd cylinders are connected together and 1000 LBS is applied to one of them, how many LBS will the other lift? Thanks:


Rodney C
 

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That's easy. 1000 lbs. if the cylinders are identical. Also, if you assume the fluid is incompressible (which is resonable) then the travel will be the same too. If your fluid is air, then the travel will be different but the force will be the same. I'd have to do some thinking if the cyliders are different sizes though.

 

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I'll second that. Its just a simple application of Pascal's Law which states that in an enclosed system, fluid pressure developed by an external source acts evenly and in all directions without changing magitude in the system.

She had all the fun and got all the money, all I got was the bills and the Jeep.....I WON!
 

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/wwwthreads_images/icons/crazy.gif You are brushing up against Bernoulli's Principle.....correction: PASCALS PRINCIPLE.... which is the basis for a hydraulic jack. Since the PSI remains constant in the system, the weight that can be lifted is a function of the square area of the cylinder. So if you have a cylinder of 1" bore and you put your hand on top of the rod and push down, you can lift more weight on the other side if the other bore is larger than 1"./wwwthreads_images/icons/crazy.gif

CJDave
A moonguy-operated Jeep Skunkworks in the "Heartland".
 
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Actually Pascals law is what makes hydrolic jack work (pressure equal at all points in all directions). Bernoulli's Principle is what alows the venturies in a carburetor to work and air planes to fly (when velocity increases pressure decreases).

 

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/wwwthreads_images/icons/blush.gif CRAP! There was a tiny voice inside that suggested that might be the case! I have always had a problem getting those two mixed up./wwwthreads_images/icons/mad.gif

CJDave
A moonguy-operated Jeep Skunkworks in the "Heartland".
 
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Bernoulli's states that two different pressures will equalize. Thus the air going over the top of the wing is at a higher pressure, it has to go faster to keep even with the air going under the wing, lower pressure.

This is also what causes your shower curtain suck in when you shower. Or, a house to explode when there is a hurricane, different pressure outside compared to the pressure inside the home.

I am a bomb technician, if you see me running, try to keep up
'85 Cj7,360,TH400,D300,Pro-jection,D44's,M/T's 35's,8274
 

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Hey, jungledog, you are close. The faster air over a wing has lower pressure than the slower air under a wing.

 
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i would think that everything being equal,that you could lift a 1,000 lbs to the half way of your rod stroke any less weight would send the cyl. in question all the way up while anymore weight the cyl. wouldn't move. my opinion

taco
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CJDave is the closest. The force is a funtion of the cylinder piston square area. Your diagram shows a 1000lb force pushing down on a area of the piston minus the piston rod. This force is transmitted over to the other cylinder which is pushing up on the whole piston (head side). This area is larger(because you don't have to subtract the rod square area) and thus you will be able to lift something more than 1000lb.

Rick
80 CJ7
 
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