Question about nozzle suction....

[mike(swWash)]

Ok, I'm starting to put together an infinity jet testing prototype and my question is, what is a good dredge vacuum pressure to shoot for? My 1st crude model get's about 5lbs of suction at the slurry intake of the jet so far.

I guess I'm asking how much vacuum should I get to be able dredge efficiently?

 

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[winners58]

Ideally, should be able to lift a bowling ball (16lb)
your testing has to have everything under the surface of the water
and the higher the outlet going into the sluice you lose pressure.


spec sheet may give some ideas;

 

[Bill_saf]

Mike
Are you testing your jet with about 4-5 feet of hose on the discharge end of the jet? If not you will not be able set it up right. your looking for (15-20 inch of vac) at the in take of the jet and 35-40 PSI at your pump hope that will help you out.

 

[Timberdoodle]

Mike, can you elaborate on your test setup. Was the 5lbs related to overall weight or PSI? A vacuum gauge is a good way to test if you have one. If you do not have access to a vacuum gauge then you can attach 10ft of clear spiral hose to the outlet of the jet and raise the hose straight up out of the water. Run the jet and measure the lift (in inches) from the surface of the water to where the height of the water stops in the hose. This will provide a rough measurement of suction vacuum in inches of water (inh20). Expect to loose around 15" of suction for every 10ft of hose length added to the front of the jet in actual operation. With a good working infinity jet and the pump running at 30-40psi range, you should be able to get lift in the range of 7-9ft in the hose. I also like to use volume measurements to determine efficiency and flow velocity up the hose under operational conditions. Here is link to a good way to measure volume. USBR Water Measurement Manual - Chapter 14 - MEASUREMENTS IN PRESSURE CONDUITS, Section 13. Trajectory Methods
Flow velocity before the jet in the range of 8-10fps is good suction for jets in the 2-4" range. Greater speed is desired the larger the diameter is for larger jets to move the bigger cobble.
Hope this helps

 

[mike(swWash)]

I'd like to thank everyone for the help and info given. I've never had a dredge and love building my own stuff....again, thank you all!


So far all tests have been on a 1" prototype without attached hoses and 50lbs of water pressure just to see what I can get with common available pipe fittings and the crude tools I have right now. Vacuum was measured with a hg vacuum gauge attached directly at the suction inlet.
Sorry for no pictures but I've been working on this in my spare time at work and didn't have time to improve or take any pictures this week. I'll be refining the ventury next just to see how much I can get out of this little bugger.

Once I'm satisfied, I'll go full scale on a 3" model and get someone with lathe to get all the angles more precisely matched up.

 

[Timberdoodle]

So far all tests have been on a 1" prototype without attached hoses and 50lbs of water pressure just to see what I can get with common available pipe fittings and the crude tools I have right now. Vacuum was measured with a hg vacuum gauge attached directly at the suction inlet.

Mike, I have a digital vacuum gauge that reads in many modes like inches HG, inches H20, PSI etc.. I just want to clarify what scale you were reading. You mentioned 5lbs which leads me to thinking you were using the PSI scale and means you have a very good working jet. 5 PSI is the same as 138inh20 or 10.2inhg.
I have found that a good infinity jet can induce approx. 10% of the working pressure into the exit flow and a reading of 5 PSI for 50psi working pressure is on the mark.
If you were reading 5 inhg then you still have a jet with good suction similar to a log jet but it could probably be tuned or improved for more suction.

 

[Gelmac]

I hope you can shoot some pictures if possible so we can follow your progress. Thanks Mike for sharing your build info.

 

[russau]

the best vacumn gauge to use is a liquid filed gauge to keep the pulses down on the gauge. yep , they aren't cheap!

 

[mike(swWash)]

That's exactly what I use, a large oil filled hg 0-25 scale gauge for best accuracy.

 

[russau]

Me to Mike! I picked up some used ones that were going tobe thrown away! I intercepted it before it hit the dumpster! they still had their calibration sticker on them , although that date was expired!

 

[Gelmac]

While researching for eductor info I found this and thought it would be of help, it has information about "Peri-jet" which -IMHO- is the infinity/couple jet is another variation of it. An interesting feature of it , is it can flush any clogs by reversing the discharge flow direction. Don't know if it is possible in gold dredge applications.

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[Timberdoodle]

It's more than possible. What I refer to as a multi-jet is basically the same thing but simplified for use in dredging. The power of a infinity/couple jet without the clogging problems with small debris. I built a lot of infinity jet's before coming up with this solution to the clogging issue.

 

[A_Sly1_U]

What's the advantage of an infinity jet over a regular old power jet? I'm in the process of building a 6" highbanker/suction dredge combo. Who makes the best jet for something like I'm building?

 

[Bill_saf]

What's the advantage of an infinity jet over a regular old power jet? I'm in the process of building a 6" highbanker/suction dredge combo. Who makes the best jet for something like I'm building?

You can run it with any pump and adjust it to your pump and it has more suction and less rock jams. Look up at the #2 post from Winner58 he posted a spec sheet on the gold divers cupple-jet only one problem gold divers in not around any more so if you want one you have to make it.

 

[Timberdoodle]

What's the advantage of an infinity jet over a regular old power jet? I'm in the process of building a 6" highbanker/suction dredge combo. Who makes the best jet for something like I'm building?

The advantage is improved suction and lift. While a manufacturer like Keene, Proline, etc.. puts a great pump/jet combo together with very good suction. I like to take advantage of the increased suction to use a smaller pump and get similar suction.
There aren't any manufacturers of infinity jets currently on the market that I know of. Gold divers couple jets were highly praised and can still be found from time to time. Most folks who are interested in infinity jets these days build there own.
Dahlke does makes a 6" tri-jet I believe.

I must have been typing the same time as Bill. Yup- Like Bill said.

 

[SHoward]

While researching for eductor info I found this and thought it would be of help, it has information about "Peri-jet" which -IMHO- is the infinity/couple jet is another variation of it. An interesting feature of it , is it can flush any clogs by reversing the discharge flow direction. Don't know if it is possible in gold dredge applications.

Site Search

The Navy has been using these for years for portable dewatering and they will "suck the paint of a bulkhead". They are made of cast aluminum and although not extremly heavy, they do have a little heft to them. You can also get one in a 6 inch, it's not considered portable because of it's weight. They have a 1:1 water ratio, every gallon pumped in, two come out.
I would love to have one for a dredge but they cost way to much.

 

[Gelmac]

The advantage is improved suction and lift. While a manufacturer like Keene, Proline, etc.. puts a great pump/jet combo together with very good suction. I like to take advantage of the increased suction to use a smaller pump and get similar suction.
There aren't any manufacturers of infinity jets currently on the market that I know of. Gold divers couple jets were highly praised and can still be found from time to time. Most folks who are interested in infinity jets these days build there own.
Dahlke does makes a 6" tri-jet I believe.

I must have been typing the same time as Bill. Yup- Like Bill said.

Gold divers couple-jets are truly praised by users. Their business was sold several years ago and the new owner didn't continue - I believe - running it. Glen Oates is the man on Infinity/couple jet design and build , he is so crafty but he's also so busy . I think he don't have time to visit forums since he moved to Alaska and then to another state. Last time I contacted him he said he can build any size of couple-jets, but didn't hear from him for a while. Agree, the couple jets are not offered for sale by manufacturers, but if an individual is good at fabricating things he can easily build one to their specification. Takes some modifications to get it right , but it is doable.

Also I think you can use a clear-water low pressure pump with a couple jet, for sizes less than 4 inch. Didn't make one as of yet, but some builders did that and they state their couple jets works really good.

 

[Bill_saf]

Gold divers couple-jets are truly praised by users. Their business was sold several years ago and the new owner didn't continue - I believe - running it. Glen Oates is the man on Infinity/couple jet design and build , he is so crafty but he's also so busy . I think he don't have time to visit forums since he moved to Alaska and then to another state. Last time I contacted him he said he can build any size of couple-jets, but didn't hear from him for a while. Agree, the couple jets are not offered for sale by manufacturers, but if an individual is good at fabricating things he can easily build one to their specification. Takes some modifications to get it right , but it is doable.

Also I think you can use a clear-water low pressure pump with a couple jet, for sizes less than 4 inch. Didn't make one as of yet, but some builders did that and they state their couple jets works really good.

From what I have reed they are love em or hate em. Imo if you ran the foot valve in a bucket the couple-jet would run cleaner with out clogging. But thats just my 2 cents.

 

[Rdg Sluicer]

What's the advantage of an infinity jet over a regular old power jet? I'm in the process of building a 6" highbanker/suction dredge combo. Who makes the best jet for something like I'm building?

You should check out the Hydro Force Nozzel. Very interesting option for a highbanker.

 

[russau]

yep and youll be helping out a good ole boy from Indiana! Chuck Lassiter is one fine guy!