Back Flush - Intake

[SMIAH]

Might be an easy one.

Anyone has more information about a system for back flushing sediment in a a water intake ?
The intake is for a fire protection system.
A pipe is delivering water by gravity to the water pump pit and is approximately 100 feet long with a diameter of 36 inches. The intake has a 4'x 4' box with bars to prevent coarser material and debris to enter the pipe. But the finer material is still entering and reducing the cross section area of the pipe.

 

[SMIAH]

Back flush for the intake and not the 36'' pipe ...

 

[dicksewerrat]

The sediment is falling out in the pipe. You have to do some maintenance on it 2-4 times a year. Plug intake, sewer jet and vac truck. Then install a grit chamber to get the sediment to fall out before the 36 inch pipe. And CLEAN OUT the grit chamder 2-3 times a year. Just because you can't see it doesn't mean it doesn't need maintenance.

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[SMIAH]

Has anyone more information about a water intake for a River?
Not for drinking water.

 

[cvg]

without reconstructing the intake structure to reduce the velocity into the end of the pipe or to provide sufficient room for sand to settle out, you cannot keep the sediment out of the pipe. Problem is therefore in the pipe, not the intake box and it can be cleaned out as Dick suggested or by pumping sufficient water back through the pipe into the river. For a 36 inch pipe this will require a lot of flow.

If river currents are pushing sand into the intake box, then you need to move the box out of the river currents to prevent that. Making the box bigger than 4x4 might help also.

 

[SMIAH]

Yes that's the problem.
Pumping water back in a 36'' corrugated steel pipe flowing in the opposite direction seems... un-realistic.