Design of a Pressure Vessel Lid Requirements 4

[K8eng]

Hello,

There is an existing pressure vessel used for pressure testing that is filled with water and brought to pressure. I need to design a lid that would handle internal pressure (filled with water) of 750 PSI max.
The construction will be made out of steel plate, A36. The diameter of the lid is 36" diameter. There are 36 holes around the edge of the circle lid that are large 1.5" bolts to secure it to the pressure vessel with an existing rubber seal (on the vessel side).
What is the minimum thickness of this lid (made of A36 steel) for this required pressure (750 PSI, water)? Will a flat plate be sufficient or should I weld on stiffeners?
How should a simulation be ran to simulate this, to see the highest deflection at the center?

Thank you in advance.

 

[LittleInch]

Well calling a blind flange a "lid" isn't a good start.

Why don't you simply buy a 36" blind flange to match the known design of the flange?

What code is the flange made to? Then just find the dimension of a blind flange to that spec. It doesn't look like an ASME B 16.47 flange, but maybe you counted the bolt holes wrong?

But if you really want to design your own flange I believe it's ASME VIII Appendix 2 to give you the required thickness. It shouldn't need stiffeners as they just concentrate the stress.

But please get someone with some experience to design this. Get it wrong and people will die if it fails.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[K8eng]

Hi LittleInch,

Thanks for the information. So the existing pressure vessel is custom designed and built many years ago, there is no code on it that it was made to. They are calling it a lid because there currently is a custom designed lid on it right now, hence why the 36 holes.

Cant find any info on the appendix, do you have any info you can share on that?

 

[JStephen]

I'd suggest to have somebody familiar with pressure vessels design and fab this.
Depending on the location and application, the whole vessel may need to be stamped.
It can likely be a flat plate but may be unreasonably thick. You may find other materials more readily available.
A flange with head welded to it may be lighter and/or cheaper.

 

[K8eng]

Thanks JStephen. More information here. So the pressure of 750 of water is LIMITED. The supply is very small, maybe 1 quart or liter of water to supply the internal pressure of 750 psi inside the vessel. The vessel has been used in this application up to 900 PSI filled with water.

 

[LittleInch]

So why not copy the existing "lid"?

What is the volume of water in the vessel?

If you have no stamps or certification, use of this vessel is almost certainly illegal. So its basically scrap metal as it stands. Sorry but unless you can show this vessel has been properly designed, fabricated and inspected your playing with fire.

It's ASME VIII DIV1 Appendix 2.

But it does seem you are way out of your depth here I'm afraid and this is not something you can learn in the job. You need paid professional help here. IMHO.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[r6155]

@ K8eng
Without any documentation you are working with scrap.
This is wasting time.

Regards