Threaded Closure

But why on earth would produce such pressures if not seeking to make diamonds? Then how?

You are not aware of the complexity. Let a professional do it if you do not want to get into troubles.

If it is a work expected by your boss convince him to accept to pay.

By the way how do you want to seal the container ? Only curiosity I went up to 30,000 psi and know what kind of problems could appear, you want to go to more than the double. Problems grow over linear!

If you have to ask, you should not be doing this.

Around 5000 Bars? Are you sure?. Thickness 11 inches?

The thickness is only 5.5 inches, which might not be quite enough (though close).

Tensile strength is 108,000 psi. The configuration of the ends is not specified, and may depend on shear strength.

Nor is any geometry of the threaded closure given, in which shear strength will definitely play a part.

These are only some of the complications to which nick name correctly alludes.

Run-of-the-mill Yellow Pages firms may not be able to help, either. This is a highly specialized case.

Yes, t:5,5 Inches

.Perhaps it refers to a wellhead, Christmas tree, specified in API 5A. For the hydro tests this pressure is necessary. The test is conducted in shielded chambers and often added fluorescent particles in the water, after decreasing the pressure, shall be check with black light on the threaded connections. The thread type is specified in API 6A. The thickness and material to be used also correspond. Companies like FMC and Cameron use it.

Regards, WP

Since the I.D. is less than 6 inches, this may not qualify as an ASME pressure vessel in the first place, but rather as some type of piping component. The safety factor for vessels is 4:1, but for piping it may be even more. Just another wrinkle in the mix!

I'm not much familiar with API, but I doubt they would contemplate pressures in this extreme range. (I could be wrong, of course.)

The OP's problem is indeed interesting, and I wouldn't want it just to be blown away. (Excuse any unintentional puns there.)

This makes me wonder what has happened to Abdel Halim Galala, one of the best world-class vessel and piping experts.

Here are the pages of the doc the OP found by himself. I did not verify and believed that at least he got the right dimensions for the pressure range BUT it is not so:for the 4"/15" the pressure is given as 60.000 and NOT 75.000! He did NOT make any computation! You will notice that containers up to 100.000 psi are proposed as series product. The company has a very good know-how and gives a LOT of technical information.

As you can see in following pictures even the steel is indicated and the design which shows that THREADS can be used for high pressure if you know how to design them.

As you see he has ALL input one needs but he wants to make it low cost being not aware of all troubles. He believes that all is to have a formula, an equation and the problem is solved.

This is the reason I say please be aware of the risk you generate giving indication to a person who after more than half a year was not able to find his way.

If he will make the container (or reactor as the company names it) it can be possible that a human being (even himself) could be KILLED. Does any body at CR4 want to take such a responsibility?

May be this guideline can help

his is the html version of the file http://www.api.org/certification-programs/api-monogram-program-and-apiqr/~/media/Files/Certification/Monogram-APIQR/monogram/program-updates/6A-20th-Edition-Purch-Guidelines-R1-20120429.pdf

WP

It appears that OP is taking a remedial class in high-pressure vessel design and has tossed his notes from last semester.

Unfortunately, I don't have any references about the design for these kind of parts.

Do you have any recommendations? Thanks in advance!

Here's a recommendation. Instead of waiting six months and trying CR4 again, delegate the task to someone locally who can actually do what is wanted. Try the local Yellow Pages for Engineering companies, and pick up the phone to a few of them.

I have a recommendation for you. Hire someone who is competent on the field of high-pressure vessel design.

• Food Industry Consulting - Food Product Development, Food ...
• Food Processing Engineering Consultants | FOODPRO.net
• Food Processing Equipment | LWG Consulting, Milking Equipment

Is it just me, or does this remind anyone of a cannon?

If it blows it will be more like a bomb.

Having observed the use of small pressure vessels for the pilot plant testing of chemical reactions for Haz Ops, I would suggest that you put this idea/project/disillusion out of you mind.

What would happen if you though an answer of mine was the best one? You could kill yourself and probably many others let alone the property damage that would be done. You don't know what my skills are but I could come up with at least 4 different great sounding bogus answers. By the way, designing pressure vessels is not something I would ever do now or in the future. Not even giving someone hints or formulas for the designing process.

Should you even consider going through with this, please do it in a location that is at least two states away from me.

Good Luck, Old Salt

Apart from agreeing with the general comment by everyone else, even to propose such an item without full disclosure (purpose/ operating conditions), and expect a rational design proposal, is quite mindless,inconsiderate, disrespectful, and other non-complimentary adjectives to boot.

actually the equations to define the thickness of wall and end cover of a pressure vessel are available in many text books. once you have the appropriate material and knowing the max. pressure you can calculate them easily. end covers can be fixed (welded) or riveted by bolts and nuts. in same text books there are equations to determine the size and number of threaded bolts. unfortunately, I failed to find any equations for the threaded end cover act as one bolt it self, except some literatures.

So I tried to ask here to find some help, that's all

Others have referred you for professional advice, and now I do the same.

The shear stress on the threads is the main issue. I hope you didn't think you would have the thread seal the cylinder water-tight as well ? I'm guessing some sort of square/ buttress thread is indicated, but this won't seal your vessel, only hold the end-cap in place against the applied pressure. Probably have to back-weld the cap, at least.

Sorry, that's as far as I go here...don't want to take the bread off some professional's plate, and then provide a faulty design on top of it!

It seems that you do not really understand any of the relevant concerns. Language such as "riveted by bolts and nuts" is off the mark. Unfortunately, you can't just go out and buy a Class 75,000 flange for this project.

Long before you even worry about the yield strength of your material, you will need to consider elastic deformation, which could affect any threaded scheme anyone might devise.

Just to give a hint, the pressure involved will tend to stretch a female threaded part, while compressing a male threaded part, resulting in poor thread engagement and cascading failure.

Given your comments this really sounds like homework (end covers at this pressure cannot be riveted), although your identical question last year would seem to indicate otherwise.

We don't do homework or offer advice to extremely unsafe practices here, but if you offer up some context into why you are asking, more details on the intended application and what you have already calculated, some nice person here may point you in the right direction. Won't be me as I only deal with explosive forces not constant pressure water vessels.

What wall thickness have you calculated since last year with the formulas you have already found?

Have you looked at outsourcing this engineering problem to professionals or just buying a suitable vessel from some food processing supplier?

He did not calculate anything. If you look at his thread from last year you will find two sites he gave and one of them is a manufacturer of high pressure containers. The dimensions are in the leaflet. I very much doubt that he did and computation I more think he found the leaflet and took the values listed there. even the stell quality is mentioned in same pages.

I would believe thet he did the computations ONLY if he put them on the screen!

I failed to find any equations for the threaded end cover act as one bolt it self, except some literatures.

Maybe because there aren't any ?? If you worked for me and proposed a screwed cap in a 75000# application, we would probably part ways, and not in such a friendly manner.

Total pressure on your proposed cap = 22/7 * 2²* 75000 = 9 428 571.428571' lbs.

Get a grip!! I have no idea how you would generate such pressure, since you insist on being coy as to the actual application of the vessel, but a screwed connection here means you will probably be screwed before it ever gets up to pressure.

An intervening post shows how it is done, but also shows some errors/gaps in the reasoning so far.

I don't think Waelnesta has the ability to appreciate the enormity his pressure value.

Otherwise he will not have thought of locking up 75,000psi of pressure with a threaded closure.

All the same I wish him good luck. I will advise that having completed his design and fabrication, the equipment pressure testing should be done in the middle of sahara desert.

You are TOTALLY wrong. It is possible to have a threaded "system" to keep the cover in place!

I did it till 30.000 psi and one can go higher but this is NOT the problem. I shall stop here because I think it is too dangerous to give more details since he can go on and an accident is so quickly done.

Only to give you a feeling if there is any minute orifice at this pressure the fluid jet can cut a man in two!

"Do not cast your pearls (of wisdom) before swine........" Matthew 7:6

(Emphasis mine)

Hence, I will not bother with a wise answer.

In order to supply any sort of information, much more information must be supplied by you. You will need to describe the device, conditions of use, and environmental specifications. I suspect you are interested in sealing a high power rifle breech because those are the types of pressures they must withstand. In any case, you are not likely to obtain any help here without supplying some pertinent information. Good Luck

Guns??? I suspect not. His application is likely here. http://www.flowwaterjet.com/en/waterjet-cutting/uhp-pumps/hyperjet.aspx

Up to 90ksi is claimed

Threaded Closure Design of High Pressure Vessel