adding power jet to gravity dredge

[Timberdoodle]

multiple jets can help provide greater suction and are usually employed when adding considerable line length. It's a tricky scenario when dealing with a low psi gravity system though as each jet adds volume to the line and the flow speed can start losing energy to friction losses. Stepping up the size of the suction hose at the jet outlet can help keep flows at an optimum level and maximize suction but this also means changing multiple components like flare size so I can't recommend it. If you want to get the best operation of the jet then building a infinity/couple style jet would provide the best suction, but they are a bit complicated. If the single log jet does help then you can expect even greater benefit by building an infinity jet. I would take this one step at a time and build a log jet first. I still have reservations that this is going to help enough with only 6ft of head.

 

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[spaghettigold]

Spaghetti

Scribble a simple drawing of the approximate gradients from where you want to dredge to sluice ... and the gradient of the river as well as the size and lengths of pipes you have at hand .... understanding that a venturi is a restrictor and not always the best option ... as in this case you are not causing flow but wanting to improve upon it


The old GPM PSI scenario

I don,t know yet where exactly i,m going to dredge in the river so far.Maybe easter i have time 2 days to dig some testholes.The river runs pretty flat most of the times,maybe 10 inches drop every 30 feet interrupted by some mild rapids with maybe 1 feet drop per 18 feet of river, surrounded by elevated banks.Sometimes we divert a portion of the waterflow at the beginning of the rapids in to the beginning of the bank(where they are at almost the same level)and then dredge further down the bank,where the rapids scoured the riverbed deeper,creating drop from top of bank to the watersurface,adding little dams if necessary. Some times we use the rapids themself.
I have two connectable 26 feet pieces of 8 inch suction hose,but can bring in hundreds of feet 4.3 " hose for water supply.

 

[spaghettigold]

Middle portion of the waterdiversion on the bank towards dredgesite.If you look i the backround of the pic you can see the steep bank on the other side of the river.We can divert the water there from further upriver to that bank,should give us some 7 feet drop there.

using rapids

Using the rapids for drop wit both hoses connected

looking up the bank to middle portion of waterdiversion

 

[spaghettigold]

multiple jets can help provide greater suction and are usually employed when adding considerable line length. It's a tricky scenario when dealing with a low psi gravity system though as each jet adds volume to the line and the flow speed can start losing energy to friction losses. Stepping up the size of the suction hose at the jet outlet can help keep flows at an optimum level and maximize suction but this also means changing multiple components like flare size so I can't recommend it. If you want to get the best operation of the jet then building a infinity/couple style jet would provide the best suction, but they are a bit complicated. If the single log jet does help then you can expect even greater benefit by building an infinity jet. I would take this one step at a time and build a log jet first. I still have reservations that this is going to help enough with only 6ft of head.

Hi timber,once i,m done with all the other stuff i have to improove i like to give it a try.
The friction comes from the added watervolume?Does that not convert to speed because pressure is low?Does this also apply when hose and flare are positioned downwards with no lift necessary?

Also,Here,s how i modifie the flare for more watervolume.As you can see the inlets are where the flare widens out .That would be what you are asking for as a countermesure to solve the added volume problem.

 

[spaghettigold]

ok,maybe i,m stretching it a bit here..too much added wide after the inlets ?also stratification would be disturbed?

 

[Timberdoodle]

Hi Sg, If your having issues with low flow in the flare resulting in hang up's in the flare then I would simply suggest installing adjustable side walls that could be set depending on the flow differences found in the field. If you need extra flow in the sluice also then the side connections should may help but they may cause other issues as you mentioned.

The friction loss question is something found in all flowing pipe systems and is the main reason you find increasing sizes of pipes feeding the gravity fed monitors used in the last century. As flow speeds increase in a pipe the friction losses increase dramatically and these can limit the total flow speed in a gravity system. Maintaining the most efficient system of piping based on flow speeds does make a big difference in cases like this where your limited to what you can use.

 

[spaghettigold]

Adjustable side walls,also a good thought.
I liked the idea of the inlets because there,s always three of us,me,my dad and a local friend. The local friend makes the sluice tender while we placed my dad with the little 4 inch in some places to sample. But then there,s always two dredges to set up ,clean up etc.Also my dad gets 80 years old this year and i like having him near in cases of flash floods or whatever.
So now with the additional inlets ,theoretically up to 3 people can dredge at different spots using one dredge .Higher throughput with less gear.

Thanks for the consultation so far,sooner or later i will build a jet just to see with my own eyes,also because maybe i visit some steep creeks in the alps with plenty of drop .

Cheers ,Emilio

 

[Timberdoodle]

Hi SG, using the additional inlets as there own suction lines for dredging is a great idea. That's thinking outside the box

 

[Timberdoodle]

This week is a bust for building and testing the jet. It was -1f this morning. Next week is expected to be above freezing all week long so hopefully I will be able to get some Idea of how the jet may work.

 

[rivets]

I am enjoying this thread



Plumbers tip


Just when you think you have concord/perceived the complexities/simplicities of water/truth ... it will give you ... an almighty kick in the backside

 

[spaghettigold]

This week is a bust for building and testing the jet. It was -1f this morning. Next week is expected to be above freezing all week long so hopefully I will be able to get some Idea of how the jet may work.

the water will still be ice cold if it,s above freezing temp
.We have time,spring is near timber

 

[spaghettigold]

I am enjoying this thread



Plumbers tip


Just when you think you have concord/perceived the complexities/simplicities of water/truth ... it will give you ... an almighty kick in the backside

Does this mean you think we can get :

-1. Zero suction increase from a power -jet fed by 6 feet head, assisting a graviti dredge?

-2. A little increase but not enough to simulate/equate 1 additional feet of head in a standard gravity set up?

-3. It can increase suction like an additional feet of head in a standard gravity set up?

 

[rivets]

Something between 2 & 3 .... but this be a guess



Just to add ...

The almighty kick in the backside I am referring to is the chastisement of the spirit of truth that lives in you ... as you ... Who works in you both to will and to do of His good pleasure ... of which the reason for this is found in one place ( there being many ) in these words


"Verily, verily, I say unto you, Except a corn of wheat (seed/Son/Word) fall into the ground and die, it abideth alone: but if it die, it bringeth forth much fruit"

 

[spaghettigold]

Something between 2 and 3 would be awesome in my book.Especially with a single jet -log.Then maybe a infinity could bring us to point 3.Maybe it takes 18 feet of head .Would still add some more spots to dredge for me though i,ve never tested them regarding gold content .

So lets hope the seed falls on to fertile ground.

 

[rivets]

The seed of the Women/soul is the liberty of Life ... it not being good for man/spirit to be alone


Its an amazing truth ... speaking of the proses we find our self's in ... which Jesus by way of parable eluded to ... albeit the whole cohesive narrative of the scriptures speak to/of this proses which can be found in everything when we brush of the perception of man/dust ... in short the proses is a scattering/division/separation/gendering which brings us to a cross ... as a point of reference which turns us back ( to see/understand ) from where/Who we came out of ... which be the same place Jesus arrived at ... and that be the place of I AM or I and my Father are one ....


I could write for days/weeks/months/years and not even scratch the surface of the patterns pertaining to the proses of spirit/soul found portrayed in the scriptures ...

Understanding that although the natural mirrors the spiritual in truth they can not be mixed together .. albeit man does this by perception and why we are lukewarm as our thoughts being a mixture of good & evil ... not that this is a bad thing .. because it is of proses ... knowledge being a necessary serpent in the path of every Son in his journey to come to the knowledge of truth/self .....


Anyway not to go on .. but where I am seeing from the only separation found in anything is the division we give to it ........

 

[Goldwasher]

The seed of the Women/soul is the liberty of Life ... it not being good for man/spirit to be alone


Its an amazing truth ... speaking of the proses we find our self's in ... which Jesus by way of parable eluded to ... albeit the whole cohesive narrative of the scriptures speak to/of this proses which can be found in everything when we brush of the perception of man/dust ... in short the proses is a scattering/division/separation/gendering which brings us to a cross ... as a point of reference which turns us back ( to see/understand ) from where/Who we came out of ... which be the same place Jesus arrived at ... and that be the place of I AM or I and my Father are one ....


I could write for days/weeks/months/years and not even scratch the surface of the patterns pertaining to the proses of spirit/soul found portrayed in the scriptures ...

Understanding that although the natural mirrors the spiritual in truth they can not be mixed together .. albeit man does this by perception and why we are lukewarm as our thoughts being a mixture of good & evil ... not that this is a bad thing .. because it is of proses ... knowledge being a necessary serpent in the path of every Son in his journey to come to the knowledge of truth/self .....


Anyway not to go on .. but where I am seeing from the only separation found in anything is the division we give to it ........

I'm confused? did jesus use a gravity dredge?

 

[rivets]

"I'm confused? did jesus use a gravity dredge?"



No ... he was a carpenter up until the age of thirty ...

 

[spaghettigold]

well here the flare mods.



cheers,Emilio

 

[Ragnor]

I have not read all the replies, so it may have been said already. Somthing that I found in my gravity dredge studies. There is a very fine line between getting enough head pressure and blowing out a layflat hose. It would be worth concidering if your gonna shell out the cash for long runs of large diameter layflat.

 

[spaghettigold]

hi ragnor
i don,t use layflat,for the 2 inlets it will be cheap pvc hose.Those will not be high pressure lines but they are there to add watervolume (if needed ,thats why i made some caps )when main suction hose provides not enough flow to clear the box properly.Also you can have more dredgers working.
Good luck on your claim by the way,something i can only dream of