LOCAL STRESS IN SHELL DUE TO FORCE ON NOZZLE

[DORU]

I know I can find here experienced enginners who are willing to share their knowledges. My problem is probably futile but I nevere managed to clarify everything in my head on this matter. Let's imagine I have a size 500mm manhole, on top of a horizontal vessel with diameter 2000mm, 10mm thick. On the manhole blind flange I have to put a pump with a weight of 500 kg. I have 0.5 MPa in the vessel. Vessel material... ASTM A516.

How can I evaluate if the shell can handle the weight of the pump ?
I searched the ASME VIII, tried to find WRC 107 & 297, I read some articles, I even got the spreadsheets from

http://www.xcalcs.com/

and tried them but I still cannot be sure if I understood well.
Please, can someone take 10 minutes or more of his time and send me some directions ? Please don't imagine I will feel hurt if the explanations are too scholastic or too "stupid proof". I am quite young and living in Romania so I will take the liberty to consider these my excuses.

Thanks and Best regards,
Doru
doru7171@hotpop.com

 

[codeeng]

WRC-107 is part of vessel design programs such as Compress and PV-Elite. Its very simple to determine max nozzle loads using this software. I did a quick check on the info you provided and calculated max radial load (+P) on nozzle as 11600 kg. This is based on grade 70 material, 0 corrosion allowance, no repad and design temp < 260 C. There may be other loads to consider, such as pump operation, and piping loads.

Regards

 

[DORU]

Thanks for your post ! I know about the existence of that software but unfortunately I do not have it. I had an evaluation copy (demo) and it let me a pleasant impression but unfortunately that software does not fit in my employer purchase list. This is why I tried to get a more &quot;academical&quot; approach. That is: &quot;hand-made&quot; calculations or free software/spreadsheets. Can someone help me in that ideea ?

 

[LSThill]

Team Members and DORU (Mechanical)

Humm, FE-PIPE and or Nozzle Pro.

Due a search on Google WRC 107. you will fine some engineering spreed sheet.

Leonard@thill.biz

http://www.thill.biz

 

[GenB]

You are looking for academical answers! good luck.
You are puting a crushing load on the vessel and if the vessel is already designed/mfd. you can not use the cover plate/pad to hold a 3/4ton. If you are to design the vessel, you have to provide means to hold the load, whether increasing the t of the shell plates or stiffeners calculated accordinglyl; even the nozzle/pad/coverplate sizing has to be designed to hold the loads.
ER

 

[GenB]

...say 1.1/4 ton load
ER

 

[DORU]

I said &quot;academical&quot; as a joke, of course... Anyway, thanks for all the tips.
I searched on google but dind't show up too many things.

 

[StressGuy]

While I've never done it myself, you can do a WRC107 evaluation by hand. I've heard from older guys of having to do so back in the &quot;good old days&quot;

Edward L. Klein
Pipe Stress Engineer
Houston, Texas

All opinions expressed here are my own and not my company's.

 

[DORU]

Please do not understand me wrong: I am doing sometimes calculations &quot;by hand&quot; due to the fact that I do not have the software !! I love computers and I would love to have all the discipline software in my computer.
The reason why I keep trying to understand the algorithms is for me to be able to build my own spreadsheets. As far as my company doesn't invest in software and I am requested for fast results, do you think I have another choice ?

 

[arto]

Use Bednar's &quot;Pressure Vessel Handbook&quot; if you're doing it by hand. Basically, it's WRC107/297 simplified [unless you get paid by the hour ;-) ]

 

[DORU]

Do you know where I can find a pdf with that book ? Or any handbook for Pressure Vessels ??

 

[warrenw]

Doru;
Bednar has a simplified formula for a point load on a vessel

stress in vessel =

1.75*((R*t)^.5)*(P/L)/t^2

for your case;
R= vessel radius = 1000mm (39.37&quot
t= thickness = 10mm (0.394&quot
P = point load = 500kg (1,102lbs)
L = Pi*diameter of nozzle = Pi*500=1571 (Pi*19.865 = 61.84)

stress in the vessel due to point load
= 5455 pa (791 psi)

 

[athomas236]

Try BS5500
Regards
athomas236

 

[GenB]

To every one,
I do not think is a good idea of some one breaking the law in providing any information/copies of any program/software.
Doru: can you stop.
ER

 

[DORU]

It was not my intention to break the law or to make someone else do it.
Stop.