Flare

Posted by: Jozm

Flare - 10/30/07 01:29 AM

Dear engineers,
What is your opinion about bellow allowable loads for 18" flare nozzle from a German vendor?
There is not any harmony between them! is it in a right way or not?
Fx=440 (N)
Fy=2040
Fz= 28670
Mx =15020(NM)
My= 22270
Mz= 140
also other 3 nozzles are same as above
Best regards
Posted by: John C. Luf

Re: Flare - 10/30/07 04:49 AM

What are what specifically punching, in plane and out of plane moments a sketch would be helpful...

But they are as they are....
Posted by: Jouko

Re: Flare - 10/30/07 08:04 AM

If you can check if the forces are from ROHR II. Global or local. Sometimes very confusing. You need to know the program to figure out what is what.
Posted by: Jozm

Re: Flare - 10/30/07 08:10 AM

actually Fz is in axial direction and Fx is in lateral, but i think 440 N or 44 kgf is not a real allowable for a nozzle which could bear 28670 N in axial direction!
by the way I must changed bellow to below!
whistle
Posted by: CraigB

Re: Flare - 10/30/07 08:33 AM

OK, suppose you're right. Unless you can convince the flare stack vendor to change his criteria, you still have to meet his requirements or risk having your employer assume warranty responsibility for the flare stack. I doubt that your employer is excited by this prospect.
Posted by: amitkshukla

Re: Flare - 10/30/07 08:03 PM

normally for flare nozzle we expect higher allowables , 440 N is not correct by any means , you can perform WRC and meanwhile talk to the german suppiler for this amazing allowables history !!!
Posted by: Jozm

Re: Flare - 10/31/07 12:06 AM

Thanks for you kindness
but for wrc I faced with this error:The ratio Ro/Rm, 0.6696 , must be > 0.0571 and < 0.571.!
regards
Posted by: John C. Luf

Re: Flare - 10/31/07 05:25 AM

Work with the vendor... if they are adamant there is naught that you can do....
Posted by: Richard Yee

Re: Flare - 10/31/07 07:05 AM

Jozm,

There is one word that finally caught my eye after repeated reading OP.

You mentioned "bellow", while most viewers (including myself) seem to focus on the matter of allowable loads, or the flare.

If the bellows element is indeed a convoluted bellows expansion joint, then it would explain the very low axial allowable moment loading. The typical convoluted bellows element is not capable of sustaining hardly any torsional loading.

It is easier for me to interpret the bellows element in terms of allowable deflection, instead of allowable loads. The bellows element would have a longer axial deflection for design, while the lateral deflection would be less for design. Torsional or axial rotation would be almost zero design.
Posted by: Moorthi

Re: Flare - 10/31/07 11:08 AM

Using Fabric Bellow at the flare nozzle ( if the pressure is too low) you can reduce the loads & also there will not be any pressure thrust in Fabric bellow, check with ur flare supplier whether any typing mistake in that.