Venturi Dredge: Why does this work?

[jimmy101]

I wonder if there are any environmental restrictions on where you can dump the outflow? You may need a permit to do the dredging and another for the outflow.

[biggsauce]

You better get some video's of this in action.

8) Will do. This will be quite an operation. The 4" pump, the hose to the dredge, the discharge hose, the HPLV pump and hoses to stir the sand up, the boat to hold them... and making it all work.

I did some rough math and its looking like it will take 12 hours to move 56 yards of sand. I'm telling everyone 20 to be safe, because when it rains, it pours.

I wonder if there are any environmental restrictions on where you can dump the outflow? You may need a permit to do the dredging and another for the outflow.

Considering my luck with the law, I better check up on that... Lord knows I don't need to be paying another fine...

[biggsauce]

Well I know I promised videos of the dredge in action, but some things fell through. I wasn't able to go down to help dredge because I had to study for some upcoming tests and nobady actually has a video camera

Anyway, the dredge failed miserably. The desing my supervisor wanted to use was a cheap (and ineffective) venturi jet design. The picture is included below. I knew that this design would be very inefficient, but I really didnt think that I would be a total flop. In order for it to have a bette chance of working, the pressure inlet should've been necked down to 2" and the suction inlet to 2" which would meet in the 4" WYE. Or I guess the suction and pressure inlets could stay 4", but exhaust into an 6-8" pipe. Regardless, an inefficient design.

What they ended up doing was using the discharge from the pump as a pressure washer of sorts. Using the flow of the canal, they were able to blast a 2-3' deep, 6-8' wide, 150 yard long trench. Not too bad for 8 hours.

Now I'll begin work on building a proper venturi jet (pictured below) in preparation for post duck season.

Also pictured is the pump. That sucker emptied a 55gal drum in seconds. Simply a beast.

[c19o]

http://www.keeneengineering.com/pamphle ... redge.html
This website has some pictures of dredge suction nozzles and whatnot.

[biggsauce]

http://www.keeneengineering.com/pamphle ... redge.html
This website has some pictures of dredge suction nozzles and whatnot.

Yeah thats where we got the idea from. Also gouldeng.com has some pretty good articles