rising main design

[maran02]

Hi all

I am trying to design a rising main of about 1.4km. The main passes through a stream, roads and field. Can anyone tell me what I should consider to design a main? I know that the main has to be 1.2m deep under road, 0.900m through field and 1m under stream. Additionally I should use air valve and wash out but I don’t know where I should put them.

Thank you for your help.

 

[bimr]

The best thing that you can do is to keep the forcemain velocity up. If the velocity is not high enough to push the air downstream, then you will have problems with air pockets.

It is good practice to avoid an air valve except on startup. You want to minimize air in the forcemain, not add it. You probably will not need a cleanout either. You should have provision to drain the forcemain for maintenance.

See the attachment.

Pumping Station Design by Robert L. Sanks is a good reference book.

 

[Alula]

Air release valves are provided at highest points and every 500m but should not exceed 1500 m if the route is plane; wash outs are provided at lowest points in order to wash the dirt accumulated at the lower points along the pipe and it is enough to provide 1 washout in your case also it is good if it is near to gorges

 

[stanier]

You will need to undertake a surge analysis.

“The beautiful thing about learning is that no one can take it away from you.”
---B.B. King

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

 

[bimr]

Alula, please review the link above. Professionals with substantial experience wrote the recommendations which run counter to your post.

 

[maran02]

thank you very much for the information. I also found out that i have a pump that runs 125 l/s we are planning to use a 400 OD SDR17 PE. How can find the average head loss and the average velocity?

Many thanks

Any help will be much appreciated

 

[cvg]

google head loss and pipe flow velocity, explains it pretty well

 

[bimr]

Q = V * A