optimizing App 2 integral type flange 2

[Ronak_Patel]

Hello all ,
what are the different parameter that govern the cost of Forged non standard flange ??

i`m trying to optimize App 2 flange .Increasing hub thickness and g1 values reduce the required thickness but they increase Outside Dia of flange and overall dimension(h + treq) .

 

[SnTMan]

Ronak_Patel, regarding cost only, you want to minimize two things:

1) Weight of raw forging, 2) Machining to produce finished flange.

These things are mostly accomplished by a short hub, small g1 dimension, small diameter bolts, large mean gasket diameter.

Having said that, the cost-optimized flange may be a service non-optimized flange. Everything is a tradeoff...

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[r6155]

Why welding neck flange?
It is not only the calculation. Think destructive testing and NDEs.

Regards

 

[Christine74]

Interesting question. The ASME Section VIII Div. 1 Appendix 2 flange calculations haven't changed much over the past 80 years, so I would expect that someone might have developed a procedure to minimize the raw forging size/weight while still meeting all of the Appendix 2 requirements. Either that or maybe there is some software package that comes up with hundreds of workable designs for a given flange and then estimates the material/machining/welding/NDE/assembly costs of each and selects the least expensive option.

Also I would expect that using a larger gasket diameter would only result in a cheaper flange if the design was governed by the Gasket Seating condition. If governed by the Operating condition I think it's probably better to go with a smaller gasket diameter.


-Christine

 

[SnTMan]

Christine74, larger gasket diameter minimizes flange operating moment, reducing thickness.

The shell & tube HX design program RCS has very well developed programming to "optimize" the body flanges. It first selects trial hub dimensions to one of several default logic schemes (which I do not understand at all). It selects gasket dimensions based on flange corroded ID and TEMA rules on gasket width. It selects minimum diameter bolts (normal default 3/4"), sets the balance of the geometry. Tests the selected bolting based on Ab, minimum distance between bolts and increments bolt diameter if needed. When bolt diameter and associated dimensions are finalized, gasket mean diameter is incremented until either bolt area limits or gasket diameter limits against the bolt circle. The balance of the calculation are then carried out. At least this is how I perceive it to work.

Quite sophisticated really, and the product of many, many years of development.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[tigny]

Hello

optimize App 2 flange

,

If trying to optimize an APPENDIX 2 flange, why not try to use APPENDIX Y to see if this helps reducing the flanges weight/dimensions (maybe not the bolt number).

best regards