pipe header size for pump running paralel

[rudiawan .]

i have a project which will using 4 pumps running parallel, the capacity for each pump is 500 m3/hr
the pump will supply the water to the header and then goes to pipeline.
my question is why my client request to use the pipe size of header , 1 size bigger than the pipeline, even tough as per calculation, velocity still on the range





thanks in advance

 

[LittleInch]

Define the sizes of the pipeline, header and connecting pipes.

But easier to ask the client....

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

 

[1503-44]

Your client believes it will help balance the flow rates going to each pump.
It will also be easier to add a pump or two in the future.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[mk3223]

To the Client, one possible reason for having a larger pump discharge header may be for new additional pipeline branch in the future.

 

[georgeverghese]

For all 4 pumps at 2000m3/hr, header size could be DN500 or DN450. If the collection header is short, DN450 may be okay.

 

[EdStainless]

I would believe that it is to minimize the impact of the header on the backpressure.


= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed

 

[pierreick]

Hi,
Don't lose your time with this kind of question, the client is the one who pays the bill!
Agree with George and 1503-44 and better distribution to cells.
I guess you have more interesting issues to solve in your plant.
Pierre

 

[1503-44]

Headers are so short that even if the pressure drops per unit length are very much different, there is little effect on total pressure drop in the header. Direct consequences of velocity however, such as erosion and noise, can be far more concerning. The short header lengths of a larger diameter don't cost very much either. What is the problem that's worth aggrevating your client. He already said yes.


--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[MJCronin]

Going way, way back to the stone age ... when I used to design piping systems along with Fred Flintstone ..

There was a general rule of thumb for, what was called "collection manifolds"

1) Make sure that the manifold cross-sectional area was equal to or greater than the area total of all inlet piping

2) It's not a bad idea to make the manifold slightly thicker wall thickness/Schedule than the inlet piping

(We would ride around Dinosaurs during lunch break ..)

MJCronin
Sr. Process Engineer

 

[1503-44]

That's a good method, but may result in a large diameter header, if there are a lot of outlets, or if all outlets do not function/flow at the same time.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[MJCronin]

Well...What methodology do you propose, 1503-44 ?..... or do you just criticize the suggestions of others ?

Did you not see where I stated that this was a "general rule of thumb" ? ... Do you understand what that means ?

MJCronin
Sr. Process Engineer

 

[1503-44]

Sorry to suppose that you had such bad Monday.

"That's a good method"

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[LittleInch]

Our OP has started 10 threads and only posted 4 replies, so I'm not expecting any more information...

One thing to consider though is the size difference of the header and the branch and the construction detail. If you're using weldolets, you often need to be two or more sizes down from the header to avoid bending the header. So say a 12x6 header branch is ok as a weldolet, but not a 12 x 8 or 12x 10 when you really need reducing tees which cost more and take longer to weld.

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