6" dredge dual quad jet..

6" dredge dual quad jet..

Okay so today we figured out we wasnt running my 8hp engine all the way.. When we pushed the 8hp engine all the way we got some suction but not enough to dredge. So i brought the flare/jet with me because i know the problems lay there.

I noticed that the 7hp pump will Almost stop suctioning when connected to the jet . So i believe maybe the 2 3/4" holes with the low clearance over the holes is too narrow and maybe i should open up more the holes . .

But im just guessing..i believe my ke201 pump is dealing with the pressure requirement from the two 3/4" holes better then the p350 ..

Otherwise everything was very stable and working properly.

I just need a good suction..what can i do now..?? ImageUploadedByTreasureNet.com1443912878.142367.jpg
 

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Hey P.
I'm trying to understand this part "I noticed that the 7hp pump will Almost stop suctioning when connected to the jet . So i believe maybe the 2 3/4" holes with the low clearance over the holes is too narrow and maybe i should open up more the holes . "
Can you provide a quick drawing on how you made the jet orifice and used the channel as the feed? If you have this info from a post last year let me know and I'll try and find it.
 

I didnt made any drawing of it but i took a picture of the jet and at the end of the chamber the holes are made and the front of the 3/4" hole has less then a 1/4" clearance over the hole..

So over the each 4 3/4" holes it start having like 1/2" to like 3/16" of clearance.
 

Ok I get it. What you have is a jet that has a much greater restriction point than a 3/4" orifice and your not passing much flow out the jets and they are probably very erratic in angle. This leads into the earlier issue with the pumps also as you haven't been passing the volume in the jet like you thought.

Here's the best way I know of to solve the problem and still use the jet. Being a 6" jet this could all be done internally if your careful.
fix.png
 

on my 4" I have a golddivers pump on a 8hp, same as the keene p201 with dual log powerjet that was made in a local shop it had 3/4" orifice
and couldn't get suction, I had to drill them both out to 1". not an easy job finally used a 1" step-bit on long drill bit extension.
 

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Tim i have about .5 inch x 3/4" internally before the hole. So if you think about it .. Is restricting less then the size of the exit hole.

Plus Thanks winners.. So now i know ke201 pump could handle two 1" holes.

What im wondering is what size big of a hole is needed for the P350 to achieve best suction.
 

I just finish noticing with the tips of my fingers i cant fit my fingers inside the jet holes ..i noticed that my 4" jet with 4 1/2" holes have more play then the ones from the 6" jet.. The hole is bigger but the clearance is much lower .. Is almost shutting the output by completely..
 

If the internal channel is 3/4" wide, then you want 3/4" tall at the end of the internal pipe, then remove all the pipe material down to the end of the channel. The 3/4"x3/4" area of channel is now the final orifice and angled properly using the remainder of the channel to control angle of jet spray. Very similar to a log jet that uses a round orifice close to the pressure hose end and the rest of the jet channel is to control angle and spreading of jet spray and the pipe is cut out in a rectangle.
When making a square orifice the total area needs to be slightly larger than the area of a circle because it takes more pressure to run through a square orifice than a round one. It equals out that a square orifice equal to the diameter of a round orifice achieves the same flow and working volume in the jet. I have been building square orifice jets for the last 3 years so I have a very good understanding of how to do this.

A round 3/4" jet has an area of .441
A 3/4"x3/4" square jet has a total area of .5625
They will both pass the same volume at a given pressure and perform the same amount of work in the jet.

Your having problems because your fitting a round peg in a square hole. Use a square peg. ie.. forget using a drill and use a small grinder and remove the pipe material from inside the jet. You wont be disappointed with the results.
 

Okay Tim . I understand what your saying now.. Thanks for the lay out..

So would i make all my orifices the same for both pumps or should i make the one for the P350 bit larger ? Like 3/4x1" ?
 

I would make them all the same and matching the flow would be by setting rpms. Right now you know both the 201 and the 350 can both run a 4" and that's basically what your supplying for total jet sizing for each pump. The goal is to build the same pressure in the pressure housing. They may run at different rpm's to match, but with fine tuning the rpm's there is a match.
 

Well i fixed the jet today .. I had to take a strip of about 3 inches put of the inside of the pipe to achieve the 3/4" x 3/4" diameter inside the pipe ..

Tomorrow i should be going to test the jet .

Ima try to record it..
 

Okay .. So im really happy with my results .

I had a very good suction ..
And i was about to dredge in 2 hours as if i was dredging with a 4" with about a whole day.

My results was about almost two grams of fine gold.
But in behind where the bigger gold has been found.
So the gold is mostly flat and some small round little pieces .

Need to find a good way to clean up all this black sand now.ImageUploadedByTreasureNet.com1444168377.586931.jpg

I'll be posting a video of it running later on today..
 

Awesome P. great to hear.
I know you mentioned it's a pain to find or order products down there. I would build a small cleanup sluice with vortex mat if you can find it and set a magnet at the outflow of the sluice to catch and remove some of the magnetite during each run and run the material a few times. Can't wait to see the vid.
 

6" dredge dual quad jet..

Ima order some because is a very slow processes panning it down completely. But for now thats all i have.

I scaled the bit of gold and it surprised me at 2.3grams plus a earing weighting .3 grains which i think is of gold.

I uploaded the video. Heres the link.

https://youtu.be/1xnWj1WDUr8

I still have a couple of things to touch upon the dredge like adding the extra 2 barrels and putting the other motor on propane. But nothing that have to do with suctioning. Thanks to you Tim and everyone else who have been following this tread!
 

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looks like you got your MOJO working now! as for the cleanup of black sands id make a Miller table to separate the B.S. from the fine gold! I prefer this device!
 

That dredge is looking good P. Nice looking flow in the dredge. Add a couple more barrels like you mentioned and your in business. Glad I could help.
 

Well i just bought the extra barrels because now im into the deeper part of the river and i definitely need the extra floatation.

Reed the ke201 pump runs on propane. Its super economic that way since a gallon of propane here is about half the cost of a gallon of gasoline .

So yeah the suction on the dredge wants to turn my hose inside out ..
 

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