2" Dredge Suction

[Millz90]

First of all it would help to have a photo of your equipment so we could see exactly what you are working with.

Second a 2" dredge is not going to move an abundance of material. (at max approx 1/2 yard per hour)

There are always ways to increase your suction power by fine tuning the venturi, adding more horsepower, going to a high pressure pump vs a low pressure pump, shortening the hose, reducing the amount of head lift, etc.

If you can place your hand up against the nozzle at the end of the hose and the suction holds it there without the weight of the hose pulling it loose while you're under water, then that's about the most you can expect with the pump you have.

GG~

Yeah let me grab some pictures of what im working with and post them. I feel like im getting confused...lol

Lots of talks about venture.......and things im not familiar with.

 

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[Millz90]

I see a couple plans to build a suction nozzle but nothing with real detail, can anyone post or send me a plan to make a 2" nozzle?

 

[ratled]

Here is a 1.5" that should get you started

Home Made Dredge Plans and Photos

This thread on a 2"
2" suction dredge | Gold Dredging Forum

You might find this helpful there are more out there.


Also, if you have to build a jet have a look at this

View attachment jet tubes.pdf


Good luck

ratled

 

[njcommercialdiver]

millz,
I have the same pump and run a 3" suction nozzle on a 10ft long hose into a crashbox, it has plenty of suction

rivits,
that insert might be a plug not just a washer, my keene 5" suction nozzle had a 1" long restrictor insert

 

[Millz90]

millz,
I have the same pump and run a 3" suction nozzle on a 10ft long hose into a crashbox, it has plenty of suction

rivits,
that insert might be a plug not just a washer, my keene 5" suction nozzle had a 1" long restrictor insert

Yeah I figured it has enough power I just want to make sure im processing/sucking up as much dirt as possible with this set up.

Im assuming its sucking what it should be, but like I said I want to make sure everything is correct.

Are you using a suction nozzle or power jet?

 

[Millz90]

So what exactly should be the angle of the main pipe? 30 degrees?

What should the bend of the inlet pipe be? I see its basically a 'U' shape but so I guess how many inches from the main tube when its running parallel? that should give me the bend on that pipe right?

If I want a 2" suction nozzle, what size should the inlet pipe be? 1 1/2"? And should this taper down to 1/2" when it enters the main pipe?

I understand the hole in the main pipe for the inlet should basically be an oval when looking down at the main pipe and it needs to be straight inline with the center of the out end of the main pipe but where is it supposed to be tapered? And what size should that hole be?

Thanks for everyones response....Im getting there....lol

 

[rivets]

I bought one ... simply because I did not have the tools to make a metal one ( hydraulic pipe bender, welding plant, jigs etc ) and seeing it will get abused a lot given the nature of its purpose ... and so was not wanting to go with making a plastic wannabe... because it will also be inferior owing to interior fluid dynamics as well as cumbersome, bulky to work with etc


Imagine sucking a gold trap and your set up is not maxed out ... but lacking ... and that fat nugget escapes you because you were shy a few (PSIA)


BUY A PROPPER ONE

 

[Millz90]

I bought one ... simply because I did not have the tools to make a metal one ( hydraulic pipe bender, welding plant, jigs etc ) and seeing it will get abused a lot given the nature of its purpose ... and so was not wanting to go with making a plastic wannabe... because it will also be inferior owing to interior fluid dynamics as well as cumbersome, bulky to work with etc


Imagine sucking a gold trap and your set up is not maxed out ... but lacking ... and that fat nugget escapes you because you were shy a few (PSIA)


BUY A PROPPER ONE

Well I have a guy that is willing to build one for me but I need to provide him the correct information. If I didn't know him, then yes I would just buy one as well. And I don't want to build one of out PVC pipe either.

 

[rivets]

Just type into google 2" suction nozzle pictures I just did and found a prospectors forum where someone made a decent one with step by step pictures .. . it took me all of five minutes to find it

 

[Millz90]

2" Dredge Suction

Fine got some pictures. Here is what I'm running.

Let me know EVERYTHING that is wrong please. The set up you see in the video and pictures didn't seem to have food suction. But I had a set up before this one that did seem to have good sucks but all hoses were the same but I was closer to the motor. Not sure if that actually matters

 

[Millz90]

2" Dredge Suction

Not sure how to get the video to save here

 

[rivets]

Sounds like back pressure ... pump not able to pump due to restricted venturi orifice and so not only are you not sucking but your pump moto is taking a beating



ps: read Hoser John's posts ... save yourself lots of pain

 

[Goodyguy]

Looks like you're running a power jet. Not as good as a suction Nozzle on a highbanker

 

[okbasspro]

Looks like you're running a power jet. Not good on a highbanker, the jet needs to be underwater as on a floating dredge or you wont get proper suction. A suction nozzle is what you need for your setup.....

And right there is the answer. Get a suction nozzle and problem solved.

 

[njcommercialdiver]

millz, you should be running a suction nozzle, like good guy said. the jet tube is for a jet flare dredge which, and should be less angle than what your running yours at, too steep of an angle and the suction suffers

 

[Timberdoodle]

Millz it looks like your working in a deep enough pool that with a few minor changes it should work well but let's verify a few things to find out if there are any issues with the jet or pump. I recommend the following steps to test the setup.
1. disconnect the jet from the sluice and suction hose.
2. fire up the pump and aim the jet away from you and you should be able to have a jet spay go 40ft or so through the air. This will help verify the jet orifice is under pressure.
3. If jet pressure looks ok then hold the jet under water and feel the suction strength. It should be very strong. Connect suction hose and feel the end of the hose, it should still be strong, but not quite as strong as without the suction hose.
4. While feeling suction strength and looking at outflow, lift the end of the jet out of the water and see if it holds good suction at a height similar to the sluice height above the waterline.
5. If suction is good, then the location of the jet is the problem and your simply loosing prime on the jet and not getting it back due to the height of the jet above the waterline. (You can hold your hand over the jet outlet to reprime when lost, but it's a pain when loosing prime often in shallows).

To solve the problem with loosing prime you can put 5ft of 2" hose between the jet and sluice and keep the jet below the waterline. If you don't have an extra 5 ft of hose try cutting 4ft off your 10ft suction line and install after the jet and put 6ft in front of the jet.
Hope this helps, please let us know how the tests went.

GG-FYI I think you meant to show 1/2" orifice in the pic for a 2" suction nozzle instead of 1/4".

 

[rivets]

Goodyguy

The effect of the venturi jet suction within its pipe being either submerged or above water line will have no effect on internal fluid dynamics ( it being a given that the suction inlet in this setup remains submerged )

njcommercialdiver

The angle of the venturi jet is fixed within the solid pipe and so the angle of this pipe (keeping within the degree parameters of the 2"suction pipe) will have no effect on internal fluid dynamics ...


Trash pumps have particle tolerances which differ from pump to pump and owing to the HP of this pump and the GPM to PSI ratio I would say its tolerance ( particle size ) is large and therefor any obstruction ( venturi ) the pump would not pump but the water in it would simply circulate resulting in cavitation and owing to the fact these pumps in effect are water cooled on a hot day running at high RPM the moto will overheat and burn out .

 

[Goodyguy]

GG-FYI I think you meant to show 1/2" orifice in the pic for a 2" suction nozzle instead of 1/4".

I stand Corrected
* changed it to show 1/2" Thanks

GG~

 

[Goodyguy]

Goodyguy

The effect of the venturi jet suction within its pipe being either submerged or above water line will have no effect on internal fluid dynamics ( it being a given that the suction inlet in this setup remains submerged )

Not from my experience......
As Timberdoodle suggested in his post above, a power jet generally looses it's prime when located above the waterline.

GG~

 

[rivets]

G.G.


I see your misconception ... Timberdoodle's suggestion is to increase the pipe after the venturi ...

Understanding that this pipe after the venturi must be of an adequate length to house pressure within it ... before the outlet ... if to short it will release pressure to soon and no suction will take place ... and if this be the case then it would be the power jet configuration that is of poor design !!! ... if not and it is the lack of PSI ... and lengthening this pipe will only add more back pressure to the pump in effect causing less suction ....