Vessel skirt thickness calculation

[Hyperboneious1]

Hi,

I'm new to the world of pressure vessel design and i'm working on calculating the minimum thickness of a vertical vessel skirt with multiple circular holes cut-out symmetrically to reduce weight...

The thickness formula from the Pressure Vessel Handbook ( page 76 in

http://www.scribd.com/doc/143865059/Pressure-Vessel-Handbook-E-Megyesy-10th-Ed-pdf#scribd)

does not not take into consideration openings.

Can anyone please point me in the direction where I may find a way to calculate the minimum thickness for this scenario?

Thanks,
George

 

[MJCronin]

You state: ".. multiple circular holes cut-out symmetrically to reduce weight..." ??????? What ???

Access holes are often necessary in the skirts of vertical towers. The skirt holes are reinforced by the methodology mentioned in the PV Handbook.

I do not understand the wisdom in trying to save weight in the skirt by cutting more holes. Does the client require this ????

The access holes are necessary for inspection/maintenance of any components (eg. shutoff valves) that may be located inside of the skirt.

You DO HAVE the PV handbook..... right ???


MJCronin
Sr. Process Engineer

 

[Hyperboneious1]

Let me clarify a bit.

The pressure vessel is 10" OD x 32" High, inclusive of top and bottom crash skirts.

The bottom crash skirt calls for it to have 2 rows of "evenly spaced" 3" OD thru holes evenly spaced for the purpose of reducing weight. You see, this will serve as a transport vessel with lots of manual handling. They want to keep weight fairly low.

Since the vessel will have no turning moment, the formula from the Pressure Handbook reduces to t = W / (pi* D *S *E)....but this formula doesn't take the holes into account.

Thanks,
George

 

[r6155]

Use 3 legs
Regards
r6155

 

[racookpe1978]

But it does has an overturning moment - even more than in a high seismic region on the ground: As a transport PV even that small it MUST resist sideways forces in nrmal driving, plus the bumps and jars as the truck crosses curbs and debris and construction ramps. THEN you must add the NHSA and OSHA transport reg's for accident accelerations and spills.

 

[MJCronin]

Ooohhhhh ....... so we get another tiny bit of the picture...

Have never heard of a "crash skirt" before (Is this something a college girl puts on before going to a fraternity keg party ???)

The Pressure Vessel handbook clearly states that it only applies to stationary vessels .....

I am confused ...... Is the purpose of the "crash skirt" to absorb energy in case of accident during transport, or does it support the vessel when it arrives at it's final destination ???? ...... or both ?????..... or neither ????

I agree with r6115 .... legs seems to be a better option.

Is it possible for you to tell us more ??????

MJCronin
Sr. Process Engineer