Micro Dredge?

[Azure]

NJ,
Definitely a different environment than the one I visit. Please be free to use and mabey improve my ideas, they have proven to work for me in several different environments around town here.
The river is clear creek west of golden Colorado. It was cold today.

Thanks for sharing your design, looks great.

I've been thinking about designing one myself, what do you think these design ideas below?

- Use a rectangle 6-8 gallon pail, the rectangle shape could allow the sluice to be contained inside the pail.
- Use a lower flow, higher PSI pump with a dryland dredge nozzle to allow blasting loose rocks.
- Use a diaphragm pump 5.8gpm@40PSI, should support a 1/2"-2/3" nozzle
- Or use a flexible impeller pump [email protected], should support a 3/4nozzle

 

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[Dogbite]

Thanks for sharing your design, looks great.

I've been thinking about designing one myself, what do you think these design ideas below?

- Use a rectangle 6-8 gallon pail, the rectangle shape could allow the sluice to be contained inside the pail.
- Use a lower flow, higher PSI pump with a dryland dredge nozzle to allow blasting loose rocks.
- Use a diaphragm pump 5.8gpm@40PSI, should support a 1/2"-2/3" nozzle
- Or use a flexible impeller pump [email protected], should support a 3/4nozzle

The round bucket was just convenient.
Containing the sluice completely within the bucket just limits capacity. I have continually increased the size and length as performance increased. More material processed the greater the reward.
The performance of the nozzle seems to require both volume and pressure. I don't think you will achieve sufficient action in the venturi to be useful.
The rigs shown draw around 14 plus amps I use a 12v 60 amp hour wheelchair lifepo4 battery that weighs about 14 pounds can achieve about 3 plus hours of continuous operation. It takes a fair amount of energy to electrically pull off this trick of moving alot of water, sand and gravel. I started off with smaller versions of this and they just really did not have very impressive power but they did work.

 

[russau]

And a light weight solar collector (foldable) would extend that run time !

 

[Dogbite]

And a light weight solar collector (foldable) would extend that run time !

After three hours my feet are cold and it's time to empty the sluice and take a short break. I then grab a second charged battery and jump back in the stream. The battery has a special charger and takes almost 6 or so hours to recharge. I have also been experimenting with 24v batteries and pumps the 24v batteries are actually about 29v and do give an additional boost to performance but a a price of course they run around 18 amp and I get just over a hour from a 24 amp hour battery. Worst problem is the sudden start up has broken the internal motor mounting in the pump housing. Working on a solution involving reinforcing the mount studs with epoxy and integrating a PWM variable speed controller with a soft start feature.my guess is that I get a 20% boost with the 24v system but reduced run time.

 

[Azure]

The round bucket was just convenient.
Containing the sluice completely within the bucket just limits capacity. I have continually increased the size and length as performance increased. More material processed the greater the reward.
The performance of the nozzle seems to require both volume and pressure. I don't think you will achieve sufficient action in the venturi to be useful.
The rigs shown draw around 14 plus amps I use a 12v 60 amp hour wheelchair lifepo4 battery that weighs about 14 pounds can achieve about 3 plus hours of continuous operation. It takes a fair amount of energy to electrically pull off this trick of moving alot of water, sand and gravel. I started off with smaller versions of this and they just really did not have very impressive power but they did work.

It's going to be a learning process, I know my initial assumptions most likely wont hold up. I ordered a 5.5GPM diaphragm pump that is supposed to do 4.5GPM at 40PSI, so i'll see if that's true. I've already found the weight the manufacturer gives was not accurate, its 50% heavier. I used calculations for a suction nozzle and adjusted it for the improved efficiency of an infinity jet. I've printed out an infinity nozzle and will test it out to see how well it works.

I'm planning on using this for crevices and under boulders. More to save time and assist me in digging rather than using as a primary tool to pass material through.

 

[Dogbite]

It's going to be a learning process, I know my initial assumptions most likely wont hold up. I ordered a 5.5GPM diaphragm pump that is supposed to do 4.5GPM at 40PSI, so i'll see if that's true. I've already found the weight the manufacturer gives was not accurate, its 50% heavier. I used calculations for a suction nozzle and adjusted it for the improved efficiency of an infinity jet. I've printed out an infinity nozzle and will test it out to see how well it works.

I'm planning on using this for crevices and under boulders. More to save time and assist me in digging rather than using as a primary tool to pass material through.

I have looked at infinity jet style nozzles and determined that they will need to be well fed volume wise as well as reasonable pressure. This is what has led me to use high volume pumps these pumps are rated for a head of 8 meters which calculated out to be around 12 psi even my smaller versionsof the nozzles were still wanting more volume and yeah they could use more pressure. Being battery powered presents restrictions as to how much battery you can carry and afford. The battery shown set me back around $270 and was the single most expensive part of making this viable due to the sheer weight of lead acid batteries and the lifepo4 has greater capacity. The picture of me operating in the river the battery is in the back pack and allows for great mobility.
The smaller nozzles I played with used a smaller 2000gph pump and it would power a 3/4" nozzle but again performance was lacking due to pressure limitations.
The nozzles pictured are 1 1/4" id. And expand into 1 1/2" pool vacuum tubing. The removable nozzle classifier tip is also larger than the nozzle tube therefore the venturi effect works Even though the difference in sizes is small the effect is pretty strong since it will pull up a great deal of material including some pretty large pebbles from a good depth and shallow as well.

 

[Azure]

I have looked at infinity jet style nozzles and determined that they will need to be well fed volume wise as well as reasonable pressure. This is what has led me to use high volume pumps these pumps are rated for a head of 8 meters which calculated out to be around 12 psi even my smaller versionsof the nozzles were still wanting more volume and yeah they could use more pressure. Being battery powered presents restrictions as to how much battery you can carry and afford. The battery shown set me back around $270 and was the single most expensive part of making this viable due to the sheer weight of lead acid batteries and the lifepo4 has greater capacity. The picture of me operating in the river the battery is in the back pack and allows for great mobility.
The smaller nozzles I played with used a smaller 2000gph pump and it would power a 3/4" nozzle but again performance was lacking due to pressure limitations.
The nozzles pictured are 1 1/4" id. And expand into 1 1/2" pool vacuum tubing. The removable nozzle classifier tip is also larger than the nozzle tube therefore the venturi effect works Even though the difference in sizes is small the effect is pretty strong since it will pull up a great deal of material including some pretty large pebbles from a good depth and shallow as well.

The infinity jet should be more efficient and require less pressure. I think the main difference between the different types of jet pumps is how the nozzle mixes with the secondary fluid. If the nozzle creates turbulence or a vortex when the fluids mix, then there will be a loss of kinetic energy and require more pressure. The log jet is the least efficient pump since the primary fluid comes in at an angle and creates a vortex.

The infinity nozzle area could have been too small, requiring more pressure. You can calculate the pressure using the bernoulli equation. In my case I calculated that I will need a minimum of 14.5PSI to maintain the same flow rate through the nozzle with a 1/2" inlet and 3/4 suction with 0.2mm wide ring in an infinity jet and 6" height difference.

From googling online, dredge jet pumps are used in other industries. Most of the research papers I came across used an annular multi-nozzle type of jet with a centrifugal pump. Maybe that might be worth testing out.

 

[Dogbite]

The infinity jet should be more efficient and require less pressure. I think the main difference between the different types of jet pumps is how the nozzle mixes with the secondary fluid. If the nozzle creates turbulence or a vortex when the fluids mix, then there will be a loss of kinetic energy and require more pressure. The log jet is the least efficient pump since the primary fluid comes in at an angle and creates a vortex.

The infinity nozzle area could have been too small, requiring more pressure. You can calculate the pressure using the bernoulli equation. In my case I calculated that I will need a minimum of 14.5PSI to maintain the same flow rate through the nozzle with a 1/2" inlet and 3/4 suction with 0.2mm wide ring in an infinity jet and 6" height difference.

From googling online, dredge jet pumps are used in other industries. Most of the research papers I came across used an annular multi-nozzle type of jet with a centrifugal pump. Maybe that might be worth testing out.

Just happened to be able to access my test pool today and made this video of the jet in the 1 1/4"id nozzle you can see the jet and the alignment straight down the barrel. You can see when it engages with the fluid and dis-engages as you mentioned. This is the over volted 24v volt version was testing the(pwm) pulse width modulation variable speed control with soft start circut. Which works nicely by the way.

 

[Azure]

Just happened to be able to access my test pool today and made this video of the jet in the 1 1/4"id nozzle you can see the jet and the alignment straight down the barrel. You can see when it engages with the fluid and dis-engages as you mentioned. This is the over volted 24v volt version was testing the(pwm) pulse width modulation variable speed control with soft start circut. Which works nicely by the way.

Great video to demonstrate it working!

Have you measured the flow rate out of the nozzle? And the total flow rate? That's be interesting to know for a baseline.