Design or calculations for davits

[snuffysmith2]

Does anyone know of a spreadsheet or any information that would take you through a step-by-step process for calculating and fabricating davits or manways?
Steven

 

[gr2vessels]

Sorry snuffy, I don't have the spreadsheet you need, but the davit calculation is only a simple structural calculation for the davit arm and the arm support brackets. In retrospective, I have never calculated any davit for a nozzle cover, used only 'standard' designs. I have only designed larger lifting devices attached to the vessel or platforms to service the vessel appurtenances, using local guvernment regulations for lifting devices.
As for manways, I used ASME VIII calculation for nozzles.
Cheers,
gr2vessels

 

[MikeG7]

I also use "standard" davit arms. They are sized mainly by the diameter of the manway or nozzele. For larger manways or heavier nozzles, the arm is constructed with a brace and thicker materials etc. I have some schemes. Please send me a PM and I can send to you what I have.

 

[bernoullies123]

Refer to: Pressure Vessel Design Manual by Dennis R. Moss - Procedure 6-1: Design of Davits

 

[muld0020]

I agree with Gr2vessels comments about a simple structural calc. I made a spreadsheet for calculating custom davits for large covers (I just did a 54" dia 3200# cover w/ davit) basically I do the following:

-look at the stiffness a cantelever beam - using moment of inertia etc... (I usually use a pipe or I-beam)
-then Caclculate the deflection of the beam
-Calculate the maximum moment
-check max shear
-check the above values to allowables
-then I check the attachment "clip" using the design loads (I use Pressure Vessel Design Handbook by Bednar)
-then I check my weld sizes/strength and make sure the vessel can handle it.
-for particularily large covers I will back it up with a quick FEA

As far as manways - it really depends on what you need (required ID, design pressure/temp). It can be a simple pipe with flange, a heavy forged ring with blind tapped holes, a special pressure seal design, or others.

 

[snuffysmith2]

Thanks Guys, I will check it out. I was asked to design a davit for a specific vessel. So I wanted to set up a spreadsheet that will give the combined stresses to fit the davits.

 

[jtseng123]

There is "bearing stress" did not get mentioned for davit design.
By the way, many companies and even PIP standard VEFV1117 have davit details up to 24"-600#. You do not need to waste your time to prove your design if the weight and moment are within these standards.

 

[IFRs]

I tried to but could not find PIP VEFV1117 - where might it be available?

 

[XL83NL]

General;

http://www.techstreet.com/direct/PIP_White_Paper.pdf

also see 162869
also check PIP VEFV 1118 (1118 is for horizontal manway davits, 1117 is for vertical manway davits)
couldnt find a direct link to #1117 or #1118, however based on this link and this link, you might need to buy the complete 4100 set ..

 

[Aodwan]

Give me your mail id, i have one excel file, hope that will help you.