DN Flange to ANSI??

[NWill]

All,

I am trying to go from a 3" MNPT fitting, to a DN80 PN10 flanged valve, to a tri clamp. The valve should have Tri Clamps on both ends for quick disconnect.

The valve is only available with DN80 PN10 flange.

The 3" MNPT cannot be changed.

I have searched for hours an cannot find a good combination of BSPP/BSPT/NPT/DN/ANSI, etc adapters.


For reference:
DN80 = 160mm bolt circle.
ANSI 150 = 152.4mm bolt circle.

I prefer not to modify the valve body.

Lastly, the valve is cast aluminum and the cluster of parts will be 304 or 316SS

So finally, anyone know where to source a DN80 to tri clamp, a DN80 to FNPT, or DN80 to BSPT with a BSPT tri clamp to thread.

Or, who can make me DN80 to FNPT Flanges

Attached is a quick drawing of a few options.

Thanks!!!

 

[pancho400cid]

Looks like you already though of tapping a blind flange.... that's one option, depending on the situation (not great from a "streamlining" perspective).

You can get a stainless DN80 weld-neck flange. If they make a tri-clamp flange that is weld-neck type, you'd just have to weld them together. I don't know anything about tri-clamp and what's available. Or you can buy a tri-clamp adapter or pipe stub-out, cut off the not-needed end with left-over length to suit, machine a bevel prep on it and weld that.

Obviously the welder / weld would have to meet the required classifications, certs etc.

 

[dr_clyde]

If it was me, I'd get blank flanges, bore them to fit a 3" TC heavy wall ferrule, then weld them in. Then you can get a 3" TC x NPT adapter and you're on your way.

Steel and O'Brien had a lot of odd adapters and fittings. VNE also has a large catalog of all these kind of parts. You may need a distributor for some of this stuff. Most off the shelf parts that are ready made I buy from the Galloup branch of the Kendall group in Grand Rapids. I don't know if they deal as far south as Ohio, but I bet they'll ship.

 

[dr_clyde]

If you need a machine shop to make you custom flanges, PM me. I can probably accommodate you.

 

[kbs2244]

I would check the cost of a catalog item against a local fab shop.

 

[NWill]

Thanks for the tips!

I figure I have two options. Find a DN80 flange and weld in a tri clamp.

or

Get a 150# flange and slot the holes a bit.


I'm going for option two first. I ordered a 304L SS 3" NPT 150# flange to play with.

Who can give me some tips on milling these out? I only have a mill drill so keep that in mind. I have limited experience on my mill and none with stainless. Any help is appreciated.

 

[welder4956]

Can't you just weld a SS tri-clamp fitting to a SS DN80 slip-on or weld neck flange?

 

[NWill]

I was trying to avoid welding. And this way appears to be more economical unless someone knows a good source for those DN fittings. I'm around $92 for a 150# flange and 3" NPT to Tri Clamp fitting.