Explosion Containment Design NFPA 69 According To ASME VIII

[blamestorm]

Hello,

We are manufacturing process vessels based on containing a dust explosion in a process vessel for European customers - design for 10 bar. There is a separate EN standard and wall thickness calculation is according to AD 2000 / European pressure vessel code.

There is a non-conventional opening to the process vessel, the container is split in half with an inflatable seal for access when the vessel is down - quick access no bolted connection. This is a non-conventional design according the AMSE / ANSI - no classic flange/bolt connection. So no flange or bolts which can be calculated as a normal pressure vessel in chemical industry.

NFPA 69 stated the container must be manufactured according the ASME VIII pressure vessel code. I understand the calculation of wall thickness and which stress to be used. However how do you contend with this non-standard special design.

I am missing something.

Hope for your help.

 

[EnergyMix]

A drawing might help, or a more thorough description. Is the inflatable seal only used when the vessel is unpressurized? What's used when the vessel is pressurized? There are quick opening connections that meet ASME, why not look into those.

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[blamestorm]

Dear EnergyMix,

thank you for your interest. The process vessel is an atmospheric design. The process runs only atmospheric. Air is blown through dust for drying.

It looks like this:

http://www.labx.com/v2/adsearch/detail3.cfm?adnumb=413286

In a worst case the dust and air mixture can form an explosive atmosphere. At an ignition a high pressure from a dust explosion can either be vented or contained. Our principle is to contain it NFPA 69. We do this by quickly closing safety vales at inlet and outlet to keep safe the equipment up and down stream from the explosion. We would like to stay with this idea.

I cannot send a design, but this design we would rather not modify either. The two comonents which then make the processor are connected by a lip. The main component is fixed to the building the movable componet is a trolley which moves on the floor in and out. Each of the two comonents share half of this lip with a latch locking mechanism to acertain correct position. There is not more than 1 mm play between the two components when brough together. On the fixed unit is an inflatable seal is fixed. When the movable part is in position the seal inflates and presses down on the movable component making a air tight connection with the two components of the processor. This seal closure is also what keeps the 10 bar explosion from venting into the outside of the processor.

In Europe we did a type test to prove its design withstanding this pressure. How would one get a design approval for such a non convetional design. A design only to work once. There must be provisions in the code to allow for a design which cannot be calculated per the codes.

I think this is what I am seeking.

Thank you for your help.