Vortex sediment separation

[Fishead]

Has anyone worked with a vortex sediment separation facility? I'm talking 800cfs, gravity powered. I've seen references to them overseas, and that they worked well, but I haven't found one in the US or with any specific design information.

Check out

http://www.cis.umassd.edu/gleung/cawfo/conf12.htm

Any help will be much appreciated.
Thanks

 

[Fishead]

Actually I missed a character

check out

http://www.cis.umassd.edu/~gleung/cawfo/conf12.htm

A cool idea... I'd like to use it, but I'm having some trouble finding resources.

Thanks for any help

 

[BRIS]

We used to use them frequently on irrigation canals to take out bed load. They work well technically but failed due to lack of maintenance.
But I assume you are looking to use in a treatment plant?

 

[bimr]

It should be obvious from the picture that the device will not work. Solids will collect on the bottom.

You have two options;

A) Put a scraper in to collect the solids, or
B) Put a 55 Deg slope in the bottom to collect the solids.

Otherwise, the thing is just going to fill up with solids.

 

[Fishead]

Thank you BRIS and Bimr,

Yes, the thought was to put a steep bottom on it to prevent buildup and direct the sediment into the center drain. BRIS, please tell me more about maintainence. This will be on the headworks of a flume to a power plant.

Thanks a lot

 

[BRIS]

Same problem as above the vortex flow carries the coarse sediment. It needs to discahrge into a basin where the sediment drops our and is removed mechanically. If it is not removed then the sediment blocks the exit and the vortex tube fills. It then needs a lot of effort to clean out. On irrigation canals we could only clear at the end of the season by which time the tube was fully cemented with sediment. The vortex tubes were constructed horizontally below the invert of the canal, approxinmatly at right angles to the flow. - the objective was maximum sediment transport with minimum water loss from the canal.

The project was in Pakistan where maintenance is a problem

 

[Fishead]

Thanks alot BRIS, it sounds like you know a lot about this type of project. Now the questions come...

1. You said "course sediment" was removed. Can you give me an approx size that was removed/remained in suspension after treatment?
2. Do you suppose that the basin would be reliable if we send the sediment right back to the river and mechanical removal isn't required or if removal was regular?
3. Can you hook me up with some design references?

Thanks a lot!

 

[bimr]

The volume that you are talking about is so large that it makes the task impossible. You are talking about 30 - 60 tons per day of solids dropping out.

Have you thought about using a lake? I am familiar with a power plant that uses a cooling lake. Water is obtained from a river and pumped to the lake. Cooling water is then taken from the lake.

 

[hydrae]

Fishead

Low energy swirl concentrators are commonly used to treat storm water with sizes ranging from .5 cfs to 10 cfs in off the shelf units and up to 120 cfs in off the shelf designs. There are several manufacturers of such devices many of whom may be able to help out in the design of a larger unit or setting up several units in parallel.
These units typically remove particles in the 250 micron down to 75 micron depending upon the type, model and size with up to 80% efficiency. At the flow you are looking at a maintenance system would need to be built into the unit cause all that sediment has to go someplace.
As storm water treatment devices, the removal of 1 to 2 tons per peak cfs per year is typical. but remember your application is continuous not intermittent like storm water treatment devices.

The above listed website, is not entirely accurate on the power requirements, there are head losses in any such device as well as losses in process water to flush the sediment away

Hydrae