"conical gusseted" nozzles on API 650 tank

[cbEngr]

Can anyone help me understand the term "conical gusseted nozzle" with respect to API 650 tanks? I'm quite familiar with ASME and less so with API 650 but I've not heard this term before. It is in a specification and required for all nozzles except a flush-type nozzle.

I "googled" the term and only got 1 hit that didn't help.

Thanks.
Craig

 

[JoeTank]

I've been doing tank stuff for almost 30 years and have never heard that term used! It's not in API-650. However, I suspect that someone wants the nozzles to be gusseted, say at four points around the perimeter. If the gussets were made to extent out to the edge of the reinforcing plate, they would have an outward taper from the pipe OD to the repad OD. They would have a conical profile. I have used such details for heavily loaded shell manholes as a means to distribute an agitator load over a larger shell area. This is not a detail accepted by the API Standard. It's an engineered solution to a problem. Hope this helps.

Steve Braune
Tank Industry Consultants

http://www.tankindustry.com

 

[cbEngr]

Steve,

Thanks. I rather suspected something like this. The one Google hit for conical gusset was for a spec that allowed plate gussets in lieu of conical gussets. Googling plate gussets found a reference showing a picture similar to what you described.
The odd part about the request is that it was for all nozzles, including instrumentation where nozzle loads aren't normally generated and a 1" dia on the roof where I wouldn't expect a repad to be needed.

Craig

 

[jdarco]

In the fiberglass tank industry it is quite common to see a "conically" gusseted flange connection. Plate gussets are also common. However, these tanks would not be made to API-650, typically ASTM D-3299! If you take a look at

http://www.beldingtank.com

they show a conically gusseted FRP flange. It's under accessories I believe!

 

[MJCronin]

jdarco is correct.....if a purchaser wishes to have a strong, reinforced nozzle on an FRP tank, he can get a "conically gusseted nozzle". These is standard detial that has been around for a long time.....for FRP and PE tanks.

But this design detail has nothing to do with API-650 steel tank designs.

I have seen plate gusseted nozzles on the heads to ASME VIII pressure vessels. Many companies require this as a standard design for agitator/mixer supporting nozzles.

I have never seen a conical nozzle on a metalic tank.

My opinion only......

MJC