24"- 2500lb Blind Flange Design (Urgent)

1. Engineering isn't about "urgent" - it's about "considered".
2. To work in a field where insufficient knowledge is available to carry out an assignment can turn a long-term contract into a short-term one.
3. To rely on an anonymous response from an international forum does not absolve the original poster from liability should the installed equipment perform otherwise than according to the design.
4. If in doubt, test it.

5. If not in doubt, test it.

Thanks, but i am looking for practical advice. Not a philosophy lessons.

That was practical advice!!

I'm with you mate.

I can't explain how to design a blind flange, instead i can give you an ASME reference.

ASME BPVC Sec-I, PG-31.

This will help to find out the minimum thickness required for your blind flange.

412 bar x 14.7 ≈ 6056 psi. How would a Class 2500 flange work for this? After temperature is considered, maybe a Class 6000 flange?

Also for me is "weird"... but, those are the data.

Tª = Amb

If somebody furnishes weird data, then somebody else needs to challenge it. (I hope that isn't too "philosophical".)

Thanks Mukesh,

I know that. The problem is that I need to design the blind flange. ASME hasn´t got a standard one, the last standard is for 12".

Tomorrow i will have more data such as: BCD, THK, etc. For design the blind flange i need to know all the parameters of the flange.

I want to say something off-topic:

One person told me something about my name so:

Here in Spain Kike means "ENRIQUE". Is more or less the same than:

jonathan---->john

ASME BPVC PG-31 Unstayed flat heads and covers

Thanks for all the comments.

I have solved the problem.

Blind cover requires THK = 300 [mm]. I used "COMPRESS" for do the same flange that exist on site and then I designed the flat/bolt cover.

I have had many problems , because, I had not enough data (the flange was not a standard one), the flange is a Ring Type Joint, and the cover flange that people on site wanted to attach was a raised face.

It was interesting.

Check for gasket requiremnet also. For that high pressur, I think you will need a ring gasket which will be metallic.

Regards;

Nadeem

Thanks Nadeem,

I used a Mineral Fiber with Binder 1/16 in. Thick; m = 2.75; y = 260.136 kg/cm^2; width = 50 mm.

I suspect this gasket will blow out and could hurt or killl someone. The flange should be designed to use a Spiral wound (m=2.5 for carbon steel or 3 for others & y=10000 psi) or Ring Joint (m=5.5 to 6.5 & y=18000 to 20000 psi).

That high pressure and size, I am sure he will need a ring joint metallic gasket.

He said he solved the problem but I doubt it as there is more to the design of this blind flange he is looking at.

Regards;

Nadeem

You're right. I checked the calculation and is spiral-wound metal gasket.

Anyway, my supervisor will review and comment me.

Thanks.

300mm is not credible for this blind flange. 30mm is likely to be closer, but that is only a guess.

Thank Tornado,

Take into account that this cover is subjected to 412 bar at Amb. temperature for the Test.

The reactor conditions are: P = 185.5 bar; Tª = 453. The Flange attached to the Reactor has a Thick = 262,5 [mm].

I checked the data sheets as You told me. I checked also the P&ID. All is ok.

So this flange is a touch over ten inches thick! That's barely plausible to me, but the idea of putting a raised face flange against a ring joint flange and expecting a Garlock gasket to hold 6000 psi on hydrotest is one I would put odds against working. Machine a matching groove in your blind flange, and obtain the proper ring and bolts. I'm sure that two foot B7 studs can be gotten, but you had better get the ring, studs, heavy hex nuts, and wrenches ordered now, then see about finding a machine shop to fabricate this monster blind. I'm a retired steamfitter, so have a more rule of thumb view than most on this list. Get with your vendor of bolts and gaskets with the measured dimensions of the existing flange, and get the proper ring. You have no chance without it. Bolt dope in both grooves and all bolts, and removal of all burs on threads so that the nuts can be hand tightened to snug. 6000 psi hydrotest is belt and suspenders country.

Thank you very much for your comment Abdel,
I will take a look, i am sure that it will be very useful for improve my knowledge.

For class 2500 and 24" is there (in ASME B16.5) a standard one?. For class 2500, de last standard flange is 12". Right?.

*That flange, wich is attached to the reactor is a non standard flange so I designed (copy from the previous calc) this flange and then I calculated the blind flange.

Be calm, I am a junior engineer everything I do goes through a more experienced engineers.

Since Table 22 "Dimensions of Class 2500 Flanges" of ASME B16.5 is not includes NPS 24, so we can assume that flange as Nonstandard, and hence the calculations as per ASME VIII-1 is applicable for both the flange and its blind flange.

Obviously -you cannot buy this from somebody's catalog - as a flat Blind Flange.

Better to treat it as a torispherical dished end.

You will get Minimum Mass flanged dished end from Pressure vessel makers

mm

Kike

Normally for this size of flange, manufacturers give grooves for Metallic O rings for hydro test purpose. Even though grooves for ring gaskets are there but particularly for hydro test at 1.5 times of design pressure normally V gooves are given on the inner flat surface of the flanges and suitable copper Ring is used for hydrotest.