Design of a pump around system

[jjdj]

Question: I work on an enviromental remediation project where we need to remove a section of a sewer line due to contamination. What we need to do, is order the correct rated pump to handle the flow rate of liquids that would normally pass through this line from the upgadient areas. There are several upgradient lines that connect to this one and the load is from runoff water only. Is there a nice rule of thumb for something like this or do you need to do some Q=VA calcs. I dont do this sort of thing much. Thanks for any help you can offer.

 

[sprintcar]

The fastest way is to compile all your system parameters (flow, SG, head change, pipe size, etc) and contact pump vendors. They can tell you what pump you need along with what driver power is required.

"If A equals success, then the formula is: A = X + Y + Z, X is work. Y is play. Z is keep your mouth shut."
-- by Albert Einstein

 

[rzrbk]

Will this be a temporary rental pump, which will pump water until the pipe is replaced, or a permanent lift station?

Either way the pump will probably need to be sized for max expected flow, which it will rarely see. If original design data is not available for the line flow, then a quick conservative estimate may be to go by the line size.( I would guess that there are tables somewhere for capacity of sewer lines of x size at y slope running half full. Some of the civil guys who work with gravity flow may know where to find.)

If temporary, you might be able to get away with a self priming pump which would periodically lose and regain suction during a rain.(depending on job duration) A diesel drive would allow some flow adjustment to better suit current conditions.

If permanent or long term, you may need a sump which would start the pump(s) at high level and shut off at low level. Several companies offer these in pre-packaged assemblies.