Parallel piping system 1

[slickstyles5]

Hi,
I am currently designing a system where I have cooling water at 30 GPM that is pumped to a manifold with 4 outlets. Currently, the 4 outlets have a similar piping line, so the flow is equally split between the 4 lines. I want to add a wye union to one of the lines, but now the problem is that I have no way of controlling the flow rates in each line? I guess I would have to install control valves to adjust the flow in each line? Is there any other way that would be more simple?
Thank you.
Gabriel Leblanc

 

[cvg]

I'm not convinced that you are getting equal flow through the 4 outlets before adding the wye...

 

[stanier]

If your system runs in a constant manner then orifice plates of globe valves could be used. If the flow rate to each end point is not that critical this would be a low cost alternative.

In order to model the flow accurately then go to

http://www.pumpsystemsmatter.org/content_detail.aspx?id=110

and download the PSIM softare.

 

[slickstyles5]

Stanier,

This pump program seems pretty useful but I can't seem to download it. When I click on the link to download, I then have to enter my information but there is no button to click to download. Maybe it is because I am in Windows 7 ... Does it work for you?

Thanks for the advice,

Gabriel

 

[zdas04]

Flow in the branches would only be equal in the rankest of coincidences. No two "identical" piping systems are ever the same at the fluid-flow level.

If you want them to be the same, put a pressure regulator on each of the four (soon to be five) lines to provide a constant pressure to the service. That way if one line has a higher instantaneous demand, the regulator will give it more water while the demand is high. Orifices and manually throttled globe valves rarely work very well in real life because demand changes too much and too frequently.

David

 

[bimr]

If the "manifold with 4 outlets" was designed such that the 4 outlets were orifices, then you would get equal flow through each orifice.

If you added an additional outlet, you probably need to resize the original orifices, if you wanted to get equal flow.

 

[cvg]

not unless the pressure drop is exactly the same upstream of all 4 orifices. Since the manifold length and total flow in the manifld approaching the 4 orifices is different, pressure drop will be different and outflow will be different.

 

[bimr]

The upstream piping pressure drop does not have to be the same because you are taking a pressure drop across each orifice and maintaining a system pressure in the manifold.

Designing a distribution system involves many variables. The size, and length of the delivery line, manifold line and laterals, the orifice size and spacing, and change in elevation are all taken into consideration.

Once you know these variables, you can select a pump. The pump moves the fluid through the supply line and manifold to the orifices.

Spreading the water out evenly doesn't happen by accident or magic. A good water distribution system will typically have a pressure drop through the orifice of around 5 – 15 ft. of H20.

 

[stanier]

galeblanc,

I have downloaded the file and I know of many others who have. try it on another system?