EN 1591 Part3 MMC BFC

[Rp02]

Have a nice day to all

I would like to say first of all I’m not an Eng. I’m a Chemist Ph.D. Researcher, so please excuse me whereas my questions and comments may results generic or incorrect.

I’m dealing with the design of a special reactor (pressure vessel) for carrying out experiments under supercritical water conditions, namely Pressure greater than 22MPa and Temperature greater than 374°C.
I choose as maximum allowable working condition 40MPa and 600°C, as material for the reactor I choose the Inconel 625 not only for its mechanical behaviour under high temperature but also for its corrosion resistance to such corrosive environments.
The reactor will have the an Internal Volume of 1L, an Internal Diameter of 100 mm and I plan to close the same with a bolted blank flange.


My problem is that, calculating the flange according to EN13445 (the code I have to apply here in Italy) the 12 bolts I plan to use results very big and surely not easy to use for a laboratory routine, moreover, due to too big bolts the gasket I plant to use (a pure copper flat ring) is subjected to an excessive stress.

I found that exist the possibility to design a Metal to Metal Contact - Bolted Flange Connection coded in the EN 1591 Part 3.

If I well understood the aim of the EN 1591 Part 3 it should allows for reducing the compressive stress at the gasket and then minimizing the bolts size required.

So, in your opinion, designing the my flange according to the EN 1591, may I resolve my problem of minimizing the bolts size and use a copper flat ring as gasket?

Thank you very much in advance for the time you will spent on helping me, and please excuse me for my not perfect English.

Kind Regards

 

[micalbrch]

I'm not familiar with the EN 1591. But doen't your reactor fall in the European Pressure Equipment Directive 97/23/EC? If so, you will need an approval of the design and of the manufactured vessel from a notified body. So, why do you (you are not an engineer) try to design such a vessel instead of giving this job to a specialized company which knows all the applicable rules and laws?

 

[Rp02]

Dear micalbrch

If I’m not wrong in interpreting the PED, devices destined to contain Group 2 fluids, with a internal volume not grater than 1L, and pressure not grater than 100MPa, should be excluded from CE marking, according to Art 3 Par 3 of the same PED and can be realized applying “sound engineering practice of a Member State in order to ensure safe use”

The real problem is that I’m a researcher, and in a perfect world I should have funds to do research and not think to other, but in the real Italy, I have to make all by my self, more things I can do, less expensive my research will result.
Obviously my calculations will be revised by an expert Eng. but more I can do by my self, less it will result expensive.

Fortunately I found Pressure Vessel Design extremely complex but also very intriguing!

Thank you for your reply

 

[vpl]

Rp02

In the interest of saving you funds, so that you have more to use for research, I suggest that you call the local regulating body. In the US, this would be at the state level -- I am not sure about Italy. You don't want to spend a lot of time and effort designing to EN1591 only to find out it doesn't apply.

As a side note, given the pressure rating you have stated (22 MPa), I would definitely not be looking to minimize the bolt size.

You might want to look at thread794-268929 for a somewhat similar situation.

Patricia Lougheed

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