PV Elite and Flange Calc

[Angsi]

Design Equipment:

1.U-Tube shell and tube hex. 2 passes on tube side (i.e channel with a single pass partition plate)
2. Confined tube sheet.
3. Integral flange on channel and shell.
4. Gasket OD/ID = 2326mm/2282mm with pass partion rib along the diameter/centreline i.e. 2282mm in length. Width of pass partition gasket is 10mm.
5. Gasket type, solid metal SS 316L, Sketch 1(a) Column 1 for Sketch 1(c) Column 1
====================================================
Re Formula 2.5 (c) in App 2:

Wm1 = H + Hp
= 0.785G^2P + (2b x 3.14GmP)

Question 1
==========
1 Can someone please let me know if the pass partion gasket details need to be considered in the calc for H and Hp and if required, how? The formula provided in Appendix 2 does not seem to take into account of the pass partition gasket details.
====================================================
Re PV Elite Calc below. With regards to the question above, PV Elite seem to have its own equation to include pass partion gasket details.


Contact Load on Gasket Surface:

HP = 2 * BE * PI * G * M * P + 2.0 * GLPG * BEpart * Mpart * P

HP = 2 * 8.3576 * 3.1416 * 2309.2847 * 6.5000 * 9060.00 + 2.0 * 2282.0000 * 1.5000 * 6.5000 * 9060.00

HP = 769360. kgf

Question 2
==========
1. Does anyone know the origin of the formula above? Especially the part where ...+2.0*GLPG*BEpart*Mpart*P comes in? GLPG= Pass partition gasket length, BEpart = effective width of pass partion gasket, Mpart = M value of pass partition plate
2. Why wasn't the pass partition information/detail considered in the calc of "H" part of the formula?

Any comments will be welcome.

 

[codeeng]

Appendix 2 deals with circular flanges only and does not cover pass partitions. TEMA R-6.2 states "...when two gasketed joints are compressed by the same bolting, provisions shall be made so that both gaskets seal..." So you need to take into account the extra gasket area when calculating Hp. Since there is no pressure on the pass partition gasket (other than a small differential pressure), there is no adjustment for H.

 

[SnTMan]

Angsi, keeping in mind you are calculating a "Flange Design Bolt Load":

The H calculation represents load on the area subjected to fluid pressure, therefore gasket properties do not appear. Hp represents additional load to keep the gasket seated, therefore is a function of gasket area and gasket property "m".

If you look at the quantities in Hp they just represent the gasket area * gasket factor "m" * design pressure, for both the ring portion and the rib portion of the gasket. The ring portion and the rib portion are separated because areas are different and gasket materials (m) may be different. Both H and Hp have units of force (say, lbs).

This equation has been used for a very long time and was included in TEMA 8th, RGP-RCB-11.7

Part UHX requires consideration of pass rib area in flange calculations, however I don't recall if the above equation is given.

Hope this clears things up somewhat.

 

[Angsi]

Codeeng, SnTMan, both of you are absolutely right about the irrelevance of gasket details for "H" calc. The state of mind I was in probably made me overlook the fact.

SnTMan, thanks for pointing out the origins of the formula used.

 

[SnTMan]

Angsi, don't feel bad, I hate to think how many hours I spent understanding it myself.