Calculating the Size of a Pressure Vessel for 9 bar/130.5 psi

In summary: If this is all you're trying to achieve, then you could probably just make a small pot and test it out.Yes definitely thickness of the walls play a role. The thicker the walls the more pressure they can withstand.
  • #1
bionic6manuel
15
0
I would like to make a pressure vessel with a pressure of about 9 bars/130.5 psi, that contains about 250 grams of water at about 175 degrees Celsius. My question is how big should the pressure vessel be.
 
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  • #2
as big as you want :biggrin:
 
  • #3
9 bar really isn't a lot of pressure.

You can work this out yourself, work out the maximum stress (hoop and axial) and compare to the pressure vessels stress strain curve at 175 C.


EDIT: Also depends what you are doing with said pressure vessel, and what the application is. Do you have to work to set codes?
 
  • #4
Despite I usually encourage people for home experiments, this time I would really discourage making it if you have not any experience with mechanical engineering (you haven't - otherwise you would not ask such questions).

Such pressure and volume seems to be not so impressive, but is pretty sufficient to shoot improperly secured valve with energy of handgun bullet, or to cause serious burns over large parts of your body.
 
  • #5
xxChrisxx I have no idea about hoop and axial, but this is what i would like to achieve. I would like to make a cube out of epoxy say 16 cubic cm and in the center I would like to put a spherical pressure chamber with a radius of about 5 cm. The pressure would be 9 bars and heat inside the chamber would be 175 degrees Celsius. Say the tensile strength is 4000 PSI of the epoxy would I be able to make pressure chamber with the epoxy
 
  • #6
Why do you want to do that? What are you acutally trying to achieve?

You certainly can't make a pressure vessel from epoxy alone.
 
  • #7
So what else should i put into the epoxy to make it strong enough. Does the thickness of the walls play a role, say i have a wall with a thickness of 5 cm

What i would like to make is a closed chamber "closed system" with a heating element and a heat sensor when ever the chamber gets to 173 degrees Celsius I shut off the devise till the temperature drops then repeat the process again.

Wikipedia says "theoretically any material can be used to make a pressure vessel". So i thought any material with a thick enough wall will hold pressure.
 
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  • #8
If you have no idea about hoop or axial (stress), you probably should not be trying to make your own pressure vessel.
 
  • #9
SteamKing said:
If you have no idea about hoop or axial (stress), you probably should not be trying to make your own pressure vessel.

No it's all right, he's got wikipedia to guide him. :biggrin:


Seriously, bionic6manuel, you've got an awesome combination for disaster here: steam, pressure and lack of knowledge/experience.
 
  • #10
DaveC426913 said:
No it's all right, he's got wikipedia to guide him. :biggrin:


Seriously, bionic6manuel, you've got an awesome combination for disaster here: steam, pressure and lack of knowledge/experience.

To DaveC426913 you are right about what you said about me. But you did not answer the question i put forward it is easy to say what you did "Seriously, bionic6manuel, you've got an awesome combination for disaster here: steam, pressure and lack of knowledge/experience". Lack of knowledge/experience I have, answer the question everybody has to learn. That is why I am posing on this forum, no matter how dumb my questions are
 
  • #11
bionic6manuel said:
So what else should i put into the epoxy to make it strong enough. Does the thickness of the walls play a role, say i have a wall with a thickness of 5 cm

What i would like to make is a closed chamber "closed system" with a heating element and a heat sensor when ever the chamber gets to 173 degrees Celsius I shut off the devise till the temperature drops then repeat the process again.

Wikipedia says "theoretically any material can be used to make a pressure vessel". So i thought any material with a thick enough wall will hold pressure.

Theoretically you can make it out of anything, even lime jelly. Not really practical though. As you are a beginner at this you need to remember the following.

Pressure vessels are made from steel.
 
  • #12
bionic6manuel said:
xxChrisxx I have no idea about hoop and axial, but this is what i would like to achieve. I would like to make a cube out of epoxy say 16 cubic cm and in the center I would like to put a spherical pressure chamber with a radius of about 5 cm. The pressure would be 9 bars and heat inside the chamber would be 175 degrees Celsius. Say the tensile strength is 4000 PSI of the epoxy would I be able to make pressure chamber with the epoxy

At 175 Celsius the usual epoxy does not work too well. It may become softer, decompose, change properties. Another thing to take into account.
 
  • #13
When you think of the level of safety 'hoops' you have to jump through when producing a pressure cooker for kitchen use (1 Bar only), I should say the 9 Bars is a pressure that demands some respect if any significant volume is involved.
If I needed to make something like that I would buy a thick steel tube and weld some flat ends to it, bolted together with strong bolts. Also, I'd include a safety valve before I went anywhere near it. I got to a great age because of this general attitude. I know it may not be cool but both eyes and an unblemished complexion makes one less unattractive to women, for a start.
 
  • #14
bionic6manuel said:
To DaveC426913 you are right about what you said about me. But you did not answer the question i put forward it is easy to say what you did "Seriously, bionic6manuel, you've got an awesome combination for disaster here: steam, pressure and lack of knowledge/experience". Lack of knowledge/experience I have, answer the question everybody has to learn. That is why I am posing on this forum, no matter how dumb my questions are

Dangerous activities are not discussed here on the PF. Based on your lack of knowledge and experience, working with a pressure vessel constitutes a dangerous activity. Thread closed.
 

FAQ: Calculating the Size of a Pressure Vessel for 9 bar/130.5 psi

How is the size of a pressure vessel calculated?

The size of a pressure vessel is calculated by considering the maximum working pressure, such as 9 bar or 130.5 psi, and the material properties of the vessel. The formula for calculating the vessel size is P x R = t x S, where P is the internal pressure, R is the radius of the vessel, t is the thickness of the vessel wall, and S is the maximum allowable stress of the material.

What is the maximum working pressure for a pressure vessel?

The maximum working pressure for a pressure vessel varies depending on the application, but for a vessel designed for 9 bar or 130.5 psi, the vessel should be able to withstand that pressure without failing or leaking. It is important to consider factors such as temperature, corrosion, and other external forces when determining the maximum working pressure for a specific vessel.

How do material properties affect the size of a pressure vessel?

The material properties of a pressure vessel, such as the yield strength and maximum allowable stress, play a critical role in determining the size of the vessel. Materials with higher strength and stress values can withstand higher pressures and therefore require less thickness in the vessel walls. However, these materials may also be more expensive, so a balance must be struck between cost and safety.

Can the size of a pressure vessel be adjusted for different pressure requirements?

Yes, the size of a pressure vessel can be adjusted for different pressure requirements. The formula for calculating vessel size can be rearranged to solve for any of the variables, so by adjusting the pressure or desired thickness, the radius of the vessel can be determined. However, it is important to ensure that the vessel still meets safety standards and can withstand the desired pressure.

What are some safety considerations when calculating the size of a pressure vessel?

Safety is a crucial factor in designing a pressure vessel. When calculating the size, it is important to consider factors such as the maximum working pressure, material properties, temperature, corrosion, and external forces. It is also important to follow industry standards and regulations, and to have the vessel inspected and tested before use. Proper maintenance and regular inspections are also necessary to ensure the continued safe operation of the vessel.

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