Two Bolt Flanges

[OscarAb]

I am working on an older (ASME Section VIII Division I, 1964 edition) shell and tube "hair-pin" type heat exchanger that has the following oddities.

1. Two-bolt process nozzles on the shell side and are cast into a fitting with only the following description, 2.5" IPS.
- Does anyone have a code reference to this?

Thank-you,

Trevor

 

[LittleInch]

I think IPS stands for Iron Pipe Size, but the flange code could be anything from 50+ years ago. Could easily be a previous version of ASME B 16.5, but whether you're able to find the 1961 or 1964 edition I don't know.

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

 

[racookpe1978]

"Two bolt" flanges is not really a "pipe size' or class of fitting, but is a (poor, sloppy) way of describing how the bolt holes on the flange will be aligned when installed.

When a (4 hole, 6 hole, 8 hole, or 12 hole or whatever) pipe flange is aligned in the vise for welding, the best practice is to align the top two holes of the bolt hole pattern so they are horizontal. There are different pins and adapters that make this easier and faster, but they all essentially put two close-fitting pins in the top two holes, then rotate the flange or valve or fitting or whatever so a level shows the two pins are flat. Then the fitter checks perpendicularity, depth of insert of the socket or slip-on flange, and the welder tacks it up. Check alignment again, then weld out the tacks.

So the spec is saying the two flanges will be aligned with their top two bolt holes horizontal.

 

[JStephen]

Are you looking at the item itself or a drawing of it?
The only place I've ever seen 2-bolt connections used was on stuff like exhaust pipes on a car.
I find some here, though, but not that size:

https://www.nationalpumpsupply.com/p03410-bell-gossett-1-50-npt-flange-2-bolt-cast-iron-ea/

A photo might be helpful.
I think there are some ancient (1950's) steel flange catalogs online, you might check through them.