System Head Curves for Force Main with Multiple Stations 1

[ccruse]

I have a pump station design that involves two lift stations along the forcemain. I have developed system head curves for the runout conditions (each pump flowing to the discharge manhole separately)

Does anyone out there have a good example of developing system head curves for force mains with multiple pump stations?

Is there a model that will help with developing them?

Thanks in advance... all help is greatly appreciated!!!

 

[francesca]

You could develop an iterative solution in a spreadsheet for just two pumps. Select your headloss method (usually Hazen-Williams), determine your controlling point and solve iteratively for the flow in the combined pipe.

 

[bimr]

Joe Evans has some spreadsheets online at

http://www.pumped101.com:

http://www.pumped101.com/#series_parallel

http://www.pumped101.com/#sdsca

 

[RWF7437]

You can probably model this in EPANet (free)!
Suggest you use Darcy-Weisbach rather than H-W for the reasons stated in the EPANet documentation.

good luck

 

[DoctorV]

Hi,

I have two separate projects where we are being asked to help design a forcemain "joining" manhole. We have separate forcemains joining into one common forcemain and it seems that this should be a place to have multiple valves to isolate the forcemains and - perhaps - redundant check valves.

The stations are less than 300 gpm and the forecmains are 4" and 6" in diameter.

Any guidelines/example illustrations?

Doctor V (don@energenecs.com)

 

[ccruse]

I have found that selecting pumps with multipule pump stations is complicated. A good approach would be to initially model the station as known inflows, instead of using pump curves, and try a variety of pipe sizes to achive a reasonable velocity of 8 ft/sec when all pumps are running. Once pipe size is determinedthen determine the range of HGLs at the outlet of each pump station. Knowing the HGLs, wet well levels, and pump flow rates, initial pump selection can occur.