Sewer Main Flow Splitter

[erikfinley]

Any details available for or advice regarding a flow splitter?

Proposed sewer extension needs to drain into two existing branches of an existing gravity sewer network. Flow must be split. Any experience with this?

 

[stanier]

Generally a pit is constructed in concrete and the base is proffiled to train the flow for low flows. For large flows as in storm water events the pit will fill and the split will be into the pipes exiting the pit.

Geoffrey D Stone FIMechE C.Eng;FIEAust CP Eng

http://www.waterhammer.bigblog.com.au

 

[bimr]

Stanier suggests, you will need to construct a flow splitting chamber. It would be very unusual to have such a chamber out in the collection system, but a flow splitting chamber is a common device inside a treatment plant to split flows.

A typical chamber would have the influent coming in on one side, flow going under a baffle wall, and then the flow going up over equally spaced weirs. All corners will need to be filleted to prevent solids deposition.

 

[eddieng27]

I have designed several "flow splitting" manholes in a parallel interceptor situation. One of the situations involved designing a vault with one pipe entering and two exiting; one of the pipes already existed and its parallel "twin" was to be constructed as part of the same project. Flow splitting is tricky and with varying flows as one would expect in a sewer system (albeit not as much variation in an interceptor as there would likely be in a collection system), I provided an adjustable "underflow-type" weir at the entrance to one of the outgoing pipes. The weir was basically a slide gate and frame that the system operators could adjust up/ down to split the incoming flow between the two outlet pipes by adjusting the amount of flow directed to the one controlled by the slide gate. My client also wanted to take advantage of the possibility of directing all of the flow into a single pipe to facilitate maintenance activities or to use only one pipe or the other until the tributary flow increased beyond the capacity of only one of the pipes. Be sure to make the vault large enough so the operators/ maintenance personnel can work around the various flow channels.