Suction header design - construction?

[whotmewory]

Can anyone share whether or not the branch pipes welded into / onto a larger ID pipe header extend down into that header?

I know that for COMPRESSIBLE flow, this is done with 60-degree angle cuts in the branch pipes extending inside the header; but is that done for INCOMPRESSIBLE flow too?

My concern are vortices and low pressure areas they generate causing the oil to reach vapor pressure. I understand that this is not a concern with gas flow.

My suction pipes and header will be full at all times. My reservoir is elevated above the header and pumps' suctions.

 

[BigInch]

They should not in any case, liquid or gas. Vorticies, excessive head loss and erosion of protruding parts can be a concern. What you don't (think you) need to worry about in liquid vs gas systems isn't important, because even though cavitation may not be a problem for gas, velocities are often consiberably higher and the worry about erosion and noise takes center stage.

We will design everything from now on using only S.I. units ... except for the pipe diameter. Unk. British engineer

 

[MJCronin]

I agree with BigInch.

IMHO, there is no reason to extend branch connections into headers based on any process flow requirements.

Furthermore, this type of branch connection would most likely be considered "unique" by the piping code of record and therby require engineering calculations or pressure testing.

 

[stanier]

Suggest you get hold of a copy of ANSI/HI 9.8

"Sharing knowledge is the way to immortality"
His Holiness the Dalai Lama.

http://waterhammer.hopout.com.au/

 

[whotmewory]

Thank you all for confirming this: thank you for your immense help.
Hey "stanier" - I am trying to convince my boss to buy that standard. WOW! $180. Even for the PDF copy! At least if I have to buy it myself I can deduct it on my taxes. Geez!

Cheers from Hurricane Happy NC!

 

[whotmewory]

Here is a Danfoss case for gas distribution where they want 60-degree slopes on suction branches extending all the way into the header.

Note that the return branches do not do this.

From reading, it sounds like they WANT the accelerated velocities; and are also using the ends of the branches to "pick up" or retrieve oil accumulated in the header for the compressors.

http://www.danfoss.com/NR/rdonlyres/DDB0F71E-0348-4DA5-A0B0-AB479B86C2A7/0/GA0451000GBPart2.pdf

 

[whotmewory]

Thank you, guys. Well, the client is going ahead with insisting I design-in these extensions down into the suction header. I cannot get them to even look at ANSI B30. Legacy.