Need advice - building a fluid bed sluice

[Au dave]

No need for a funnel. The pressure of the water hitting the wall will force the water through the tubes. On the underside of the top deck inside the trap you need to mount a bar that goes sideways across the trap. When the gold goes through the Grizzlies it will run into or knock into this bar causing it it lose energy and sink or the disturbance from the water running into the bar will help it sink. The bar does not need to be very large maybe 3/4" at most and mounted close to the Grizzlies.

I have read of this interference bar but have not put one in my diy zooks , both of which do catch fine gold... do you think it would be an advantage in my case..

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[Golden_Crab]

I was under the impression the bar is there to knock float gold down into the water?

 

[KevinInColorado]

I was under the impression the bar is there to knock float gold down into the water?

And to direct the paydirt down into the trap so it doesn't just blow over the top of the trap and out the exit.

 

[Goodyguy]

Thought I would share some additional info that I have learned from trial and error.

I have found that the number and diameter of the fluidizing tubes as well as the holes along with their orientation need to be "tuned" to the size of the trap to create optimum fluidization.

One proven hole pattern is to have holes across the bottom of each tube as well as out the sides of each tube.
Here is an example of a staggered hole pattern that I use with success.......




I would recommend that you NOT install the tubes more than 1/2 inch from the bottom of a tube to the bottom of the trap.
And you also should not allow more than 1 inch above the tubes to the lip of the overflow port of the trap. The reason why is: The more material that collects above the center line holes in the fluid tubes the harder it is to keep the trap fluidized.

For example:
Allowing 1/2" below the tubes and then 3/4" for the tubes and 1" above the tubes would set the trap depth up to the bottom lip of the discharge port at 2-1/4". A larger deeper trap doesn't translate to more gold, only more material to try and keep fluidized plus more concentrates to process. The most important thing is to keep the material in the trap fluidized so that the gold can settle through it. Make sense?

Much easier to do when the mass of the material in the trap is reduced. In other words, the water pressure created inside the tubes must be greater than the pressure created from the weight of the material in the trap for the contents of the trap to become/remain fluidized.

The holes on the sides of the tubes should not be spaced more than 1" apart and should be aimed at the gap between the holes on the tube next to it amounting to a jet of water into the material between the tubes every 1/2" same with the holes on the bottom of each tube 1 inch apart but with the holes on the tube next to it filling the gap. (not sure this description paints the right picture) It works out if you start the holes 1/2" closer to front of the trap on every other tube. The distance between tubes should not exceed 2" and from the outside tubes to the walls of the trap should not exceed 1"

As far as the proper diameter of the holes in the tubes to create the outflow jets that actually do the fluidizing is where it gets complicated.
If the holes are too large exit pressure goes down but if the holes are too small then too much back pressure is created if the incoming flow into the tubes is not great enough. Do you see the catch 22? Also too many holes will reduce the outflow pressure just as too few will not create an even fluidization.

A happy medium must be found as there is no way to precisely control the incoming flow into the tubes other than using a water pump with an adjustable flow control valve.
Long story short I've found that typically anything over 1/8" holes is too big and anything below 1/16" holes is too small.

One thing not discussed in the above info was the best diameter of fluidizing tubes to use.
I use tubes that have a 5/8" inside diameter and determine how many to use by the overall width of the trap.

When using other sizes bear in mind the diameter used will have some affect on the internal pressure so drill your holes accordingly.

* I forgot to address trap length. You want your trap to be long enough from point of entry to overflow port to give the gold it's best chance to settle out of suspension. I recommend at least 8" of length. My first trap was 8" wide by 6" long and it worked ok but I think a little longer would have been better.
(at least that's what she said)

Also run your sluice as level as possible. The steeper the angle the less efficient your trap will be. See diagram below

The bottom angle (45 degrees) is way too steep and will cost you some gold. Shallower angles up to 25 degrees are more acceptable.

Hope this helps,
GG~

 

[Vertigold]

Here is a photo of the diverter from t-net member: benny. He added a plate on the end (the light thing in photo) of his mini BGT, to make the "trap" deeper.
The diverter strip runs between the metal ends of the bungee cord and is attached to the bottom of top plate of the trap.
You can see it just above the wire grizzly.

http://www.treasurenet.com/forums/attachment.php?attachmentid=1001530&d=1401236580

You can check your trap for leaks in the dark-or-at night with a flashlight or bright light.

 

[Goodyguy]

Here is a photo of the diverter from t-net member: benny. He added a plate on the end (the light thing in photo) of his mini BGT, to make the "trap" deeper.
The diverter strip runs between the metal ends of the bungee cord and is attached to the bottom of top plate of the trap.
You can see it just above the wire grizzly.

http://www.treasurenet.com/forums/attachment.php?attachmentid=1001530&d=1401236580
You can check your trap for leaks in the dark-or-at night with a flashlight or bright light.

Here is another example of a diverter baffle that I found to be too big and causes scouring if the flow is fast ...............

 

[AUT_Fraggle]

I think DN32 is too big. I use DN32 tubes (3) on my powerd bed.
Due to the diameter they are almost s big as the depth of my bed.
So there is not much space for the sand, and bigger gravel blocking finer sand moving to the bottom.
The diverter baffle helped a bit using ma trap.

Michael

 

[DukeArdelis]

I haven't been online for a few days, and I see a lot of new things.

I bought new smaller tubes, 20 mm in outer diameter, and 13,2mm (1/2") inner diameter.

Thanks for the diagram of the holes GG, a picture says a 1000 words.

I will get go work this week, and will update on the progress.

Thank you all for your help.

 

[KevinInColorado]

I haven't been online for a few days, and I see a lot of new things.

I bought new smaller tubes, 20 mm in outer diameter, and 13,2mm (1/2") inner diameter.

Thanks for the diagram of the holes GG, a picture says a 1000 words.

I will get go work this week, and will update on the progress.

Thank you all for your help.

Perfect choice, should work great if you can figure out the right pattern of holes

 

[Hunt4gold]

Not sure if this is the case with the Prospector or Miner models, but my 36" Bazooka Sniper only has holes along the bottom of the two fluidizing tubes. No holes along the tubes sides.

 

[Goodyguy]

Not sure if this is the case with the Prospector or Miner models, but my 36" Bazooka Sniper only has holes along the bottom of the two fluidizing tubes. No holes along the tubes sides.

The sniper uses two tubes and has a 4 1/2" wide trap. A staggered row of holes along the bottom of the tubes would be all it would need to fluidize the traps capacity.
As far as the other models go I have no idea of their hole placement even though I once had a miner model I never looked at the hole placement.

I do have an early model prospector in the process of being sent to me so I'll use my dental mirror and see what the hole placement looks like after it arrives and report back.

Perhaps someone else knows?

GG~

 

[Goldwasher]

there are (should be) two rows of holes in all tubes

 

[mofugly13]

there are (should be) two rows of holes in all tubes

Spill it, Goldwasher!!

Kidding, sort of. I assume two rows of holes at 5 and 7 o'clock? Or thereabouts? I did mine like goodguy, holes at roughly 5, 6, and 7 oclock. But I did use a different pattern. I calculated the area of the tube inlet based on the ID of the 1/2" PVC I used, and then figured out how many 1/8" holes I could drill per tube, so that the total area of the holes was less than the area of the inlet. It was around 20 or so. I drilled all those holes, and then during testing, ended up plugging some up. I think the total number of holes I left open per tube was around 12 or so. My Bazooklone Prospectror seemed to catch the gold just fine.

 

[Johnnybravo300]

My sniper and prospector also. Only at the bottom.

 

[arizau]

It seems reasonable to assume that the two rows of holes are drilled so that the aim is towards the bottom of the box at it's midpoint between the edge of the box and the center point of the tube or, in the case of adjacent tubes, the mid point between the tubes. One should be able to eyeball it pretty closely but, with some known measurements and a basic knowledge of geometry, the distance/placement of the holes could be determined.

 

[goldenmojo]

I have a set of factory sniper tubes on my shelf but I do not feel it is my place to give out the specs on them. Todd and Chris saw many people build knock offs of their sluices over the years and they never retaliated in any way against them. If you could figure how to build one and not go into mass production they were all for it. Goldwasher and Goodyguy have given out valuable ideas. Common hydraulic theory like that used in sprinkler irrigation and a little trial and error and anyone can solve the puzzle with what's out there already. Good Luck.

 

[Goldwasher]

You want enough fluidization to mimic what happens in a pan. The heavies settle very easily when they can. The trap in a Bazooka is pretty dang close to a jig. With the grizzly there as a scalper. As the dense slurry hits the trap it concentrates because of density and hydraulic pressure. Good times when it's firing on all cylinders

You could make a 4 ft power sluice with three perpendicular hydraulic traps and get great recovery.

 

[Goodyguy]

Fluid beds are great at insuring that the heavies will settle to the bottom.
Here is an example of what I call a "super fluid bed highbanker sluice" that I built to dredge into ..............
* the black mat shown in the photo on the right is the damper flap laying on top of the slick plate. The dredged material runs underneath the flap as it exits the crash box.




The sluice collects about a gallon and a half of concentrate that only takes three minutes to run on the gold cube reducing it to about a cup or so of super concentrate.
Works pretty good at recovering the fine glacial gold found here in Indiana.




GG~

 

[Goldfleks]

Any vids of that super fluid dredge in action? Looks great. You always have the most interesting equipment.

 

[wildminer]

Goodyguy, that is a very interesting unit. I'm very jealous of your skills and ideas!