Engineering and pressure related questions

[kelseytischler95]

How did you find PF?: Friend

I need to move a 2000 pound weight up twenty feet into the air on top of an eight inch diameter piston (surface area of 50 square inches) how much steady pressure would i need to achieve this and overcome the friction on the piston itself. Im trying to lift a door/wall

 

[berkeman]

Welcome to PF.

How is this heavy weight balanced or secured on the piston? What keeps it from falling off?

 

[kelseytischler95]

It is directly attached to the top of the piston. Think a piston with a box attached to it. With built in (tank style tracks on either side

 

[kelseytischler95]

The tracks are going to be used to spin gears on the outside so i will have to figure out the force requirements for spinning this gear as well and add that psi to the total but i think baby steps would be good

 

[kelseytischler95]

Note that i can use two pistons if needed to relax the psi required and increase stability

 

[kelseytischler95]

Also note that any help received in this forum used twards a finished product will be credited by name if wanted in the final build

 

[phinds]

and overcome the friction of the piston itself

Given the great specificity of the question, I am confident that the answer is "some amount".

 

[kelseytischler95]

I was pretty specific. I need to move two thousand pounds of weight twenty feet into the air. I will be using a piston with a surface area of 50 sq inches. How much actual pressure will i meed to achieve this. I get the math of making it float an inch and i get the engineering of how i could just go max psi and bash it up too fast. I am asking for a controlled ascension. How much psi. The rest if read properly was additional food for though after the first question. Thank you for your reply

 

[kelseytischler95]

In summation will the same psi required to lift it an inch (with a stop bag) move it the height of twenty feet without a stoppage ceiling or will i need more pressure

 

[Lnewqban]

Does your piston have a stroke of 20 feet?
Keeping safe stability, and a non-return retaining mechanism, for all that lift may be your biggest problem.

Pressure anywhere inside the hydraulic system, at any height, is simply weight/cross-section area.
A 15% safety factor will take care of any piston friction.

 

[berkeman]

I need to move a 2000 pound weight up twenty feet into the air on top of an eight inch diameter piston

So something like this, but 20 feet tall instead of 7 feet tall?

 

[jack action]

People over here are reluctant to help someone lift 2000 lb, 20 ft in the air, when they have a problem understanding some very basic concepts. Let me reassure you: no one here wants to get credit for your project we don't know anything about. Just say "Some guy on the Internet". The experts will understand.

The pressure is measured in Pound per Square Inch (psi). You have 2000 pounds per 50 square inches or $\frac{2000\text{ pound} }{50\text{ square inch}} = \frac{2000}{50} \frac{\text{ pound} }{\text{ square inch}} = 40 \frac{\text{ pound} }{\text{ square inch}} = 40\ psi$. The answer is in your question ... unless there is something else you haven't told us about.

This pressure will hold your load. Slightly increasing it, you will begin to move your piston once the static friction breaks free. Then you will have to reduce it a little bit to keep the velocity constant. From this point, increasing the pressure more and more will accelerate your load faster and faster.

 

[Vanadium 50]

I am a bit afraid here.

@jack action is correct, a final pressure of 40 psi will hold this. But when you are half way up, unless you are adding gas as you go, your pressure needs to be twice that. One foot up, and you need 800 psi. At some point, this may break your equipment. If it doesn't, your weight will zoom up like a rocket and keep going even after the force on the piston equilibrates.

 

[Baluncore]

I was pretty specific. I need to move two thousand pounds of weight twenty feet into the air. I will be using a piston with a surface area of 50 sq inches. How much actual pressure will i meed to achieve this. I get the math of making it float an inch and i get the engineering of how i could just go max psi and bash it up too fast. I am asking for a controlled ascension. How much psi.

What fluid? Air, oil or water?
Let's assume hydraulic oil as it is safer than air, and is low friction.

2000 lbs / 50 sq" = 40 psi.

The pressure throughout the process will need to be very close to 40 psi, independent of height.

The rate of movement will be determined by the rate fluid volume is pumped from a reservoir tank, into the cylinder.

To "bash it up fast" will require a high volumetric capacity pump that is capable of about 45 psi. The power rating of the pump motor will decide the speed of movement.

150 years ago, this would have been done with the town water supply, operating on a piston with a leather seal, greased with lard.

 

[jrmichler]

The OP is unable to properly do a simple P/A calculation, and has not been able to properly describe the system. Therefore, they certainly do not understand the need for, and how to, calculate such details as the safety factor against buckling. A 2000 lb mass 20 feet in the air is dangerous by itself. When supported by a system designed by somebody that cannot properly describe that system, it is too dangerous for PF.

Thread closed.