Infinity jet design opinions needed

[mike(swWash)]

Here's what I have been able to design using the limited info available online.
Please feel free to give feedback about what I got wrong. I'd like to get it as close to right the first time as possible. The only part of the jet I don't have the ability to make myself is the tapered cone on the outlet end, but my local machine shop can. I'll then weld it all together myself.
I know a high pressure pump will create more suction but with the supposed 3x increase in suction over a standard type suction nozzle, I wonder if a much cheaper lower pressure trash pump might work at least as well as a standard nozzle until I acquire a better pump.

 

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[winners58]

here some info on the couple-jet it has some sepc's for water needs
.

 

[mike(swWash)]

Wow! Some good info, Thanks

 

[Timberdoodle]

I modified your pic with my recommendations. I built many infinity jets like this and it is easy and works great. The pressure chamber doesn't need to be more than 4-5 inches long. 15degree cone 3"-2" reducer (can find exhaust header reducers already made online, but look for a good cone shape)

 

[mike(swWash)]

Thanks for the info.
I thought the flair needed to be tapered inward the same angle as the cone for smooth flow.

Should the jet be located on the crashbox like a jet log or on the hose end like a standard style?


This is what I'm considering using for the flair.

 

[Timberdoodle]

The outward flare creates the jet aperture far enough back along the wall of the cone to utilize more of the cone for jet stream control. I use 16g stainless for this design or you can use 16g regular steel and allows the aperture to be made easily. Thick walled steel like your picture could be ground beveled on the inner pipe to create the aperture or just cut flush since it will naturally sit further back up the cone, but since thin walled steel doesn't have enough dimensional thickness to utilize the length of cone required, I employ this technique and it makes for a much lighter jet than thick steel. You will also want to install set screws to hold the inner pipe centered.

Jet placement is best determined by how you are using the dredge. If you are working a lot of shallow areas where air is often sucked into the system, then placing the jet further forward in the line helps reduce loss of prime. Otherwise the best suction will come from having the jet back near the crashbox. Placing the jet 4-5ft forward of the crashbox can give good suction and reduce the problems of losing prime in shallow water.

 

[mike(swWash)]

Very good point on the setscrews to hold alignment of the inner tube.
I also miss-named what the above pieces would be for, I meant to use one of the above for part "B ", the outer cone, since the taper seems nice and gradual for less flow resistance. I'd like to use stainless exhaust pipe for part "A", and what about adding a second layer, part "C", to the end of "A", and grinding a taper for more flow contact with the cone?

 

[Bill_saf]

May I make a suggestion on the end that you have for fine adjustment dont thread if your going to michine the plat michine it from bar sock and have a collar going out the back and cut inside for (2) o-rings and have a ss all thred with 2 nuts for adjustment.

just my 2 cents

 

[Timberdoodle]

The point of the flare is to create a focused aperture that points directly back and let the 15deg cone shape the jet stream angle for best operation. It simply reduces the need for welding additional thickness/shaping the inner pipe with a grinder. Without some form of angle control, the main jet stream will travel the walls of the exhaust pipe and will still work, but will not be as strong as a jet stream that is focused to the middle of the jet. I simply present a simpler way to provide this directivity. A jet aperture does not need to be a long length of restriction to work well. As far as the bell reducer, there are plenty of 16ga stainless reducers available for automotive and sanitary applications which will be easier to weld together than the thick weld reducers and are significantly less expensive.

 

[Timberdoodle]

Good idea Bill. He will want adjustability for both setting the gap and cleaning debris out of the orifice.

 

[russau]

plus the addition of a vacumn gauge at the devices inlet tube will give him a "best" adjustment setting for the pump he is using! this way he can tell at what adjustment will give him the strongest / best suction !

 

[mike(swWash)]

Sounds like a plan to me. Thanks for the help and I'll try to keep updating my progress as I go......probably more questions will come up later but you've helped me a lot already.

 

[Timberdoodle]

For a good 3-2 stainless reducer, Copy this to search ebay STAINLESS CONCENTRIC WELD REDUCER 3"-2" SANITARY PIPE TUBING 76-51mm
You can also buy a tee for a pressure chamber if you don't have the tools to make a side entrance STAINLESS STEEL WELD TEE 3" SANITARY PIPE TUBING 76mm
good luck

 

[mike(swWash)]

I saw both of those on ebay......looks like better ready made parts!

Once I get it all together, I'll put the design online for all to see....

 

[Gelmac]

Thanks a lot, guys . I learned many things from your discussion on this build.

Mike, I hope it turns good at the end and do a perfect job for you.

 

[Dogumentor]

I am new on this forum, just registered, and I have designed my own Infinity Jet. But my design is based on a 24 Volt DC pump, all standard PVC pipe parts. The jet sucks great, but....
More about it can be read here.

Martin Zaugg

Once I become more familiar with navigation on here, I shall open a new thread.

May I mention that postings on this forum has greatly helped me with my own design I did 6 months ago. For this I like to say a heartfelt thanks to all and like to share my results.

Cheers all

Martin aka Dogumentor

 

[russau]

Well Martin welcome to the site! I just built a 2 inch version sorta similar to yours . except im using my eng/pump from my 2 inch dredge

 

[Dogumentor]

Great, I knew this is the right forum for my project!
Having an eng/pump is of great advantage and I like to see more about your design. I will stick with the 24 V bilge pump. as this setup creates a tougher challenge to overcome cavitation and I like to build it back pack friendly. Give me a couple of weeks to prepare for a new thread as I am sure you guys will be on to it.

Cheers
Martin

 

[Timberdoodle]

Hi Martin, Welcome to the site. Good to see someone else messing with bilge pumps and submersibles. Certainly challenging and I'm looking forward to seeing more.

 

[russau]

Great, I knew this is the right forum for my project!
Having an eng/pump is of great advantage and I like to see more about your design. I will stick with the 24 V bilge pump. as this setup creates a tougher challenge to overcome cavitation and I like to build it back pack friendly. Give me a couple of weeks to prepare for a new thread as I am sure you guys will be on to it.

Cheers
Martin

Backpack friendly with 24 vdc sounds kinds heavy with the batterys. maybe if you had a small generator and made a voltage reducing setup but then your defeating the purpose of backpackable and the non-mechanized areas.