Dawn of the stealth dredge

[LeeOregon]

Recently I have been working on a project, and have decided to share the results with the forum as it happened to be this forum that inspired my initial ideas.

Project Goals:

-Noise: Create a dredging system that is quiet
-Efficiency: Do as much as possible as far as moving material, with as little input energy ass possible
-Performance: Sacrifice as little as possible in the ways of performance in comparison to a 'real' gas powered dredge

Project Results:

Suction will be provided by an 'infinity jet' aka 'Couples Jet'. Sluice box will be submerged. Both of these design options will increase efficiency, as energy will not be lost to 'lift' material above the water line. In fact there should be little lifting involved, as the sluice box and nozzle will be at roughly the same height. Pressurized water will be provided via submersible electric pumps.

With these design choices the noise level will be that of the generator alone, and generators are pretty darn quite these days. The only sign of dredging, once the system is in place, is an extension cord running into the water. Otherwise there is only the compressed air line for the hookah.

 

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[LeeOregon]

Issues encountered in first uploading attempt, let me try this.




edit: For whatever reason, that took forever. If theres any interest I will try to get some more photos, video of operation uploaded.

 

[ARC]

I for one am interested... and would enjoy watching / looking at the photos you post.

I like what you have done thus far... I will open and study the photos after typing this.

From the small pics alone I can say what I see so far is interesting.

I like to watch innovation and creation in areas like this.

Even if something ends up not working the way intended... there is much to learn from that as well.

 

[LeeOregon]

A bit more information:

As far as I can tell, this is providing more suction than a normal suction nozzle (Not a jet log, no experience with that as yet). Granted, the gas powered pump I was using with that particular 3" nozzle was kind of crappy.

The upside? This suction is currently being provided by 2, 1 hp pumps. Theoretically those 2 pumps are small enough to be run off a very quite and pretty small generator like the cheap Predator 2000. In practice though, that generator doesn't have enough oomph to start up both pumps, and stalls out a trying to turn on the second. Im not sure whats going on here, as each pump is drawing something just over 10 amps after startup. As a 1hp motor, it shouldnt draw much over 6 amps after startup. Right now thats kicking my poor little generators butt.

 

[LeeOregon]

View attachment 1851886

This infinity jet was constructed as 3 main parts as seen in the photo above. From right to left there is the female taper housing, male taper sleeve, and sleeve bushing.
View attachment 1851889
The female taper housing as seen above. The taper is 11 degrees. The 3 screws you can see are to adjust the end of the male taper so that its perfectly centered in the female taper, providing an even jet all around. For whatever reason if I left the end alone, it tended to provide more flow on one side than the other.
View attachment 1851890
The male taper sleeve, also at 11 degrees. I ran out of aluminum, so 3d printed this in black PETG. It is solid, surprisingly strong; Leads me to believe that an entire jet assembly could be printed this way. My only concern would be abrasion resistance, so I will only do this section for now and see how it holds up over a bit of time.
The bulged section seen at the end provides a longer length of taper, in theory giving the water more time to become co-linear with the direction of flow down the pipe.
View attachment 1851892

The sleeve bushing. A slip fit on the male taper sleeve allows the gap to be adjusted, with the 2 screws used to pin it in place. Ive found greatest suction thus far at the smallest gap.

View attachment 1851893
View attachment 1851893
The male taper sleeve inside the sleeve bushing.

View attachment 1851898
I was unable to find the connector I wanted, a 1 1/4" to 1" Y fitting. So I made a few up myself. Again, 3d printed in black PETG

 

[ARC]

The attached photos are coming in as invalid and not opening... try reposting just the photos.

 

[LeeOregon]

Assembly, from right to left


Does this one work?

 

[LeeOregon]

Here I have taken off the hose just to see how far it might shoot



Moving a little bit of material



It creates a nice, even flow 360 degrees around the perimeter

 

[LeeOregon]

Are any of these uploads working for anyone?

 

[DizzyDigger]

Lee, the last images are showing.

I believe the issue you're having has to do with the image size,
as the files you posted are very large. Here is your last image,
and I reduced it from 2.1MB down to 354kb. Easy to do in
Paint.



There is an adjustable setting on your phone or camera for the image size. I believe
yours is set to a larger setting, making for very large file sizes and huge images. Images
would post up better and be viewed much easier if you reset that to something along the
lines of 1000x800 pixels (or thereabouts). Images would still be plenty big for internet use
without any degrading of the image, and they would load and post much faster.

 

[ARC]

No pics.

The original post pics are fine... not sure what might have changed that caused his next post pics to be "invalid".

 

[russau]

I viewed all your pic's and you did a real nice job of making this system. The system is doing a good job so far but some higher pressure / volume pumps look like it would really enhance it's performance! BUT all in all you've got a nice set up and did some good work ! Generator's can be made quieter with a " low tone muffler". these are expensive (over a hundred dollar's ) but do the trick!! I've been wanting to replace my muffler on my 6.5 KW generator but I'm having a hard time finding one to be a bolt in replacement ! I'm a (old) welder and I could cut and reweld the pipe configuration to work , but right now I don't need it , so it'll have to wait ! I think the "low tone "muffler would be a asset to your system! GOOD LUCK on your project and keep us up-2-date ! Several years back I was building a 5 inch subbie similar to your's BUT old age and a wore out buddy changed my mind !

 

[LeeOregon]

3d printed sleeve

female taper housing, w/ adjustment screws to center the two tapers

Sleeve bushing

3d printed Y adapters

 

[LeeOregon]

How does one typically measure the performance of a dredge? Is it in the vacuum it creates and if so, where do you measure it? By capping the inlet and measuring the vacuum it pulls? Or perhaps its the vacuum it pulls whilst the line is open, running clear water?

Or do you measure it in the PSI created, downstream of whatever injection method your using, again running clear water or by capping the outlet.

Most of the ratings ive found for dredges just go by the power of the motor attached to it. But im finding that number usually has little to do with how well the actual system performs. For example, I tried out a 6.5 hp powered, high pressure water pump on a 3" dredge. This current system with the 2 electric 1hp motors is already outperforming it.

 

[Reed Lukens]

The movies all worked fine.
From what I saw, your output didn't come close to a 3" dredge motor and was barely able to pick up the rocks that you had in the pool, but it worked. Great job! Can you show us some pictures of the power cord connector in the water?

 

[Phil]

Very cool setup!

As for the gen stalling out, electric pumps can draw upwards of 3X rated amps during startup. You need a bigger generator.

 

[russau]

Lee you need a "Vacuum gauge" to measure your suction from the pump / nozzle . I installed my vacuum gauge after my nozzle somewhere in your line , where ever it's convenient for you to install. Now I record what is the vacuum at various RPM's of the engine (or motor that your system is using . and when that's done I remove the gauge and plug the hole permanently . I like your using the 3D printer to make your part's !! I used to cut and weld my metal parts from metal that I had in my shop! KEEP IT COMEING !! Also your vacuum will change as the material you suck up increase's ! The more you HOG material, the vacuum will drop and you end up with plugging your hose with cobble / sand and you don't want that!! Learn to let the dredge suck the material to your nozzle and by all means USE A BLASTER HOSE to help free up that material ! My good friend John "Hoser" Oates made me a firm believer in the blaster hose ! I haven't heard from John lately , anybody heard from him

 

[LeeOregon]

The movies all worked fine.
From what I saw, your output didn't come close to a 3" dredge motor and was barely able to pick up the rocks that you had in the pool, but it worked. Great job! Can you show us some pictures of the power cord connector in the water?

The actual connectors are all out of the water. Its just a normal 120v plug, plugged into an extension cord at the moment. I didnt want to pay for actual water resistant connectors, to be able to connect it under water.

 

[LeeOregon]

Very cool setup!

As for the gen stalling out, electric pumps can draw upwards of 3X rated amps during startup. You need a bigger generator.

Thats the confusing part for me, and the stalling part of the project at the moment. The pumps are rated at 1hp, with a 13 amp max draw. However when its in normal operation, each pump is drawing just over 10 amps. Thats 1200 watts, or 1.6 horsepower. Now, I have heard of manufacturers over stating the power ratings, but never of a manufacturer understating the power. Its perplexing, and annoying, as I got the generator sized for a 2 hp load, plus hookah compressor.

A bit of a background on this project;

I go out prospecting on the river with my little pontoon boat. Something like this:

Its just big enough to carry my 2000w generator, pans, hookah setup, diving weights, buckets, shovel, crevasse sucker, etc. I can put in at whatever convenient upstream location and float downstream to the takeout, exploring and prospecting as I go. For locations that are within rowing distance, I plan to take this system out.

As such, I cant go too big on the generator; it would also kinda ruin my wish to be small and efficient, doing as much as possible with as little input energy as possible. It would be hard to explain why I need such a large generator to any nosey noseys, just to run my 1 hp electric air compressor.

Ideally I would like to upgrade to this, the best power to weight to noise ratio ive found so far:

https://www.generac.com/all-products/generators/portable-generators/gp-series/gp3000i

But with the current pumps that is just not feasible. At 2,400 watts for the electric pump motors, plus whatever the air compressor draws, I am over the 2,300 watt running capacity of the GP3000i.

So I am stalled out at the moment, stuck trying to figure out a generator that will fit on the rack of my pontoon boat and not be crazy noisy. (Thats why Ive been sticking with the inverter type generators so far, such as the Predator 2000 or the Generac GP3000i. They are veryyyyy quite). Any generator gurus out there have a goo suggestion?

 

[LeeOregon]

Heres some of the research ive done thus far. The Predator 2000 at the top, which was tested and found lacking. Followed by other options. Trying to find a upgrade in the same ballpark of size weight and noise.

Predator 2000 1600 Runinng Watts (13 amps) 22.6"Lx12.6"Wx18.5"H 48 lbs $500
Generac GP3500IO 3000 running watts (25 amps) 19.3"Lx16.9"Wx16.4"H 74.3lbs $789
Generac GP3000i 2300 Running watts (19 Amps) 22.2"Lx13.3"Wx18.4"H 59.5lbs
WEN 56380i 3400 Running Watts (28 amps) 23.2"Lx18"W x20.1"H 99Lbs
WEN GN400i 3500 Running WAtts (26 Amps? 19.8"Lx13.8"Wx18.9"H 66lbs $421
Briggs strat P3000 2600 Running Watts (22 Amps) 28.5"Lx15"W x 24"H 90lbs $864