standard for non-API clamp hub connections?

[oldrichard]

I'm working on a 20-3 BOP that has hubbed end connections. This is one of the old Cameron-developed connections and this is one of the sizes that did not get adopted by API. So I'm trying to find out if there is any standard that governs this. The only source we have found is the vendor Woodco, and they don't reference where they got the dimensions from. I can't find any 'original' information as to what the dimensions and tolerances should be for the hubbed end, or the clamp. Anyone know of anything, a standard or anything that was formally published?

 

[LittleInch]

This forum is a bit of a backwater so you might need to see who responds then try in the pipelines and piping one.

But I think this really maybe a bespoke design from Cameron. Those shoulder forces must be immense though and will be a FEA type thing.

BTW what's a 20-3 BOP. I know what a BOP is, but what do the numbers mean? 20" 3000 psi?

I'm sure you've seen this if you've looked at woodco, but it's quite illuminating as to the history.

https://www.woodcousa.com/a_wst/clamp_history.htm

This bit might be relevant

"In the course of reviewing the design of Cameron hubs, API chose to eliminate a few sizes that had stress levels which exceeded the conservative values desired for an industry specification."



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[oldrichard]

Thanks for responding. Yes, it's a 20-3/4" bore to be exact and 3000 psi working pressure rating.
The hub connections were Cameron's design, kind of a hybrid between the Grayloc and existing API connections. They're almost extinct, I've been in BOPs for 10 years and this is the second time I've worked with one. But we're replacing a stack for a customer that is set up that way and doesn't want to change.
I have read that history Woodco gives, it's the most comprehensive I've found. I don't know the numbers, but the 20-3 hub must have exceeded the 2/3 of yield strength at working pressure that API 16A allows. You can pretty much look at it and see that even at only 3K psi it's probably working pretty hard. So it didn't make it into the API standard and we're trying to figure out if there's anything resembling a standard we can refer to.

 

[LittleInch]

I think this is an occasion where the design became the standard, not the other way around....

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[oldrichard]

Right. Without ever really getting standardized. Thanks for your inputs.