6" 300# - 4" 150# Reducer 4

[ANDYDABICO]

Can any one help,

I need to reduce down from 6" 300# (std wt) to 4" 150# (std wt)over a distance of 4" (100mm). I have looked at using a dedicated casting and using a concentric reducer with slip on flanges, can anyone suggest another method or is ther an off the shelf item that i could consider (material is carbon steel & cost is a major factor)

 

[JStephen]

I doubt you'll find an off-the-shelf item for something like that. If you have those two flanges at 4" face to face, can you even bolt them up? Seems like you'd run out of room on the backside.

You can fabricate reducers as conical sections. You may can find a reducing flange- 6" pattern for 4" pipe- and attach it to a 4" pipe and 4" flange. Or make one out of a steel blind flange.

 

[MortenA]

Cant you just use 600# and replace the existing 300# flange with a 600# (or dont you have the room?)?

Best regards

Morten

 

[katmar]

If pressure drop is not too much of a factor then you could simply get a blank flange for the 6" side and machine it to take the 4" pipe welded into it. This will also solve the short face-to-face problem for access to the bolts.

I have done this on low pressure, ambient temperature applications. But be aware that I am a chemical engineer and not a piper, so maybe this sort of thing is not allowed where you have high stresses and rigorous codes have to be applied.

 

[Shmulik]

ANDY,
I would suggest you as follows:
Drill a 102.36 mm (4.03”) hole in center of a 6” #300 blind flange.
Weld a 4” #150 WN. flange on the back of drilled 6” blind.
The unit you get now is of 112.7 mm long.

If the length of 100 mm is essential, you can do the same with a 4” #150 LWN flange (adjusting the hole diameter at the 6” #300 blind flange accordingly). The length of the LWN flange will be adjusted in order to have the required overall length of 100 mm.

I hope it helps…

 

[1969grad]

Can you use a reducing flange and eliminate the 4" flange connection?

 

[unclesyd]

You might want to download the SIFCO catalogue and look at their flanges.

http://www.insertflanges.com/download.shtml

 

[ANDYDABICO]

Thanks everyone,

Shmulik, your suggestion seems to be the most practical for my application and was one of the ideas that we actually came up with here, i will now have a prototype manufactured.

Once again thank you all for suggestions

 

[rconner]

ACIPCO manufactures a steel Flange Adaptor, with details as shown at

http://www.acipco.com/adip/specials/adaptor.cfm.

 

[jte]

Andy-

If you're working a system which requires you to meet B16.5 (designing the piping to B31.3?) then I'd strongly suggest you take a look at B16.5 2003 Table 6 (pg 68) or Table F6 (pg 162) Note 1. Seems to me that with a 6" blind with a 4" hole punched into it and a standard weld neck flange welded on you now have a 6" flange which does not comply with B16.5. I know its commonly done, but you still need to cover yourself and your company.

Two ways which might bring you back into B31.3 compliance:
1) Evaluate the blind per VIII-1 as a flat head with a large opening. See UG-39(c).
2) Use a 4" long weld neck flange as your connection. See B16.5 2003 2.8 (pg. 3). This design would inherently give you the required hub dimension at the 6" blind in accordance with Table 6 or F6.

jt