Hello Sir

One tank has been given to us for analysis using ASME Sec VIII Div II in PV Elite.The tank has the following specifications

Working pressure: Atmospheric to 20mm WC (g)(0.2 KPa) of Vacuum
Working temperature: 50-70 degree centigrade.

My question is does this tank analysis come under the scope of ASME Sec VIII Div II?

If it comes,Why?

Plese help me.

there is no scope defined by ASME for applying div.
but seeing the working pressure it seems very obvious to go for div 1.

Hello naganarayan

This does not fall into the scope of ASME Section VIII, Division 1 or 2. However, you can use the code to evaluated the design. I have just written an email to you. I think this is the tank with the very shallow cone at the bottom. My email points out that the tank is subject to collapse (because of the shallow cone).

Sir,

Similar tank is in use here without ring for the cone.Could you please explan me the basis on which it will collapse?

Dear Ray,

Can you post the same in our forum? It will be helpful for all Design Engineers.

...Jayakumar

This is the email I sent on this very subject:

"Hello Naganarayana

In ASME Section VIII, Division 1, you will find in Appendix 1-5 and Appendix 1-8 the cone to cylinder junction analysis. Where the cone is attached to the cylinder, there is an inward force all the way around the junction which is pulling the cylinder radially inward. This force has to be counteracted by a junction ring which prevents the collapse.

I have been an engineer for a long time. In my early years, I worked in Cape Town, South Africa. I used to visit the wineries. At those wineries, the wined was stored in stainless steel tanks with shallow cone bottoms. Sometimes when the tanks were completely filled, the bottoms would collapse. I was called in to solve the problem. By knowing why they collapsed, I was able to solve the problem. I simply told them to put a certain size ring at the junction, and the collapsing no longer occurred.

A little knowledge goes a long way."

Now, in the case of tanks that did not fail, either you were lucky, or the forces in the cone were not sufficient to cause collapse (I have no way of knowing). There is an analysis of shallow cones in the API 650 storage tank code. If you go to Appendix F in that code, you will be able to do the cone junction analysis.