Pressure Vessel Design for Isostatic Pressing

[solidpoly]

My first thread. I am interested in potentially building a pressure vessel that will be capable of 5000 psi at ambient temp. Approx 24" ID x 16" height. Water with anti-corrosion additive will be used as fluid. The bottom can be fixed but the top needs to be easily opened and closed for isostatic pressing operation. I have looked at commercial builders and the cost and lead time is extremely high/long. I have been able to research some of the design parameters and constaints and I understand the forces. I believe my requirements fall into the ASME VIII div 2 standards. I have found a copy in the city library. Are there web sites, documents, video or specific books that I might read that will help me smoothly through this engineering quagmire? I am a mechanical engineer with fluids background but never worked on this type of project. Maybe there are economical "pre-engineered" designs that I might be able to copy. Can anyone steer me?

 

[solidpoly]

jte: I did not find the SF numbers in the BPVC chapters. It was in High Pressure Vessels by Fryer & Harvey. I think you are suggesting that I do not have to iterate thickness from Div-1 or Div-2 formulas for thickness to insure Stress SF is > 4 or 3. And I have not focused on cert process. If I cannot build and cert after the fact, what do I need to do?

 

[TGS4]

solidpoly - perhaps the best way to approach this is to contact the Pressure Vessel authority in your jurisdiction. Where in the world are you located? We can help by pointing you in the right direction.

 

[solidpoly]

I live in Buffalo area. Thanks

 

[TGS4]

http://www.labor.ny.gov/workerprotection/safetyhealth/dosh_boiler_safety.shtm

These are the rules for your state (I'm assuming that by Buffalo, you mean Buffalo, NY. FYI - this is an international forum of engineers, so we try to be as specific as possible when referring to our locations. You could be in Buffalo, MN, or Buffalo, WI, or Buffalo, OK, or Buffalo, WY, or Buffalo, TX, or even Buffalo in South Africa.)

My understanding of the rules in NY is that the design and fabrication of what you are proposing to do is governed by the Safety Health regulations, and everything must be in compliance with the ASME Code.

For what it's worth, prior to the development of the ASME Code (or its adoption in many jurisdictions), people have managed to create very nice craters in their workplace/neighbourhood with their non-standard pressure vessels. The energy stored in your little vessel could probably take out your workplace and a few neighbours too. You liability insurance is up-to-date and completely covers you for this, right?

 

[solidpoly]

Yes that is Buffalo NY. Earlier in this chain of discussion I stated I was in NY. I should not assume you have read it all. I do understand the safety issues of such a device. I am a Mechanical Engineer with good experience level with fluid systems. I intend to meet all requirements of the BPVC. Unfortunately they are extensive and only a very experienced Engineer or Vessel Designer would know all of them. Therefore I may miss something. I cannot afford to pay for a vessel from a commercial manufacturer. Therefore I have done a fair amount of reading and research (library and internet). I have a preliminary design complete and trying to verify my numbers. I have an PHD friend performing some FEA. As you already know, sometimes the FEA results are only as good as your model, assumptions and ability to understand results. And then react for another iteration. And I have done the stored energy calculations and I do not want any craters. I feel I am a competent Engineer that needs some guidance. Are you willing to asses my design?

 

[TGS4]

I saw that you were in NY after my reply.

I intend to meet all requirements of the BPVC.

Good. As a competent engineer you can appreciate that it's not a 'pick-and-choose' set of requirements either.

Unfortunately they are extensive and only a very experienced Engineer or Vessel Designer would know all of them. Therefore I may miss something. I cannot afford to pay for a vessel from a commercial manufacturer.

As a competent engineer, I hope that you see the shortcomings of your position. Yes, the requirements are extensive. Yes, they are intended to be used by experienced personnel. Yes, given your experience, you will most definitely miss something (probably something important, too). If you can't afford competent help, then you can't afford to do this project. Full stop.

Are you willing to asses (sic) my design?

For a reasonable fee, my company does this type of work all the time. There are many out there that do. In my opinion, your biggest hurdle is going to be the fabrication aspect and having your vessel U-Stamped. Perusing the NY-State regulations, there's no way around that requirement - although you should contact them yourself to confirm that.

Will I do it for free - NO. Would you want some anonymous person on the internet who "claims" to be an expert review your design? I would hope not.

One final aside - in my jurisdiction, where I am registered as a Professional Engineer, a competent engineer knows when they are practicing outside of their area of competence. To practice outside their area of competence would land them in a heap of trouble for an ethics violation. To not know the delineation of where their area or competence ends would also be an ethics violation. Any of these could result in loss of licensure, fines, etc. I want to make sure that this doesn't happen to you.

 

[solidpoly]

I did look you up before I responded to the last thread. Your company and your position were not "anonymous person on the internet who "claims" to be an expert". You obviously underestimate the skills of others. I thank you for your comments.

 

[TGS4]

I forgot about my information on my profile.

I'd rather underestimate and be pleasantly surprised than overestimate and be sorely disappointed. Glad that you fit in the first category.