Barrels in fast water

omnicron said:
I'm loving all the pros in here! I love your design, and I'm going to copy parts of it! Hope you don't mind. How you had the lift system on the rear of your sluice was what I was considering but was going to do the front also so I could keep her up out of the water if I needed to move. Like how you also did that with your flare/jet. It's prob the grizzly that I'm seeing. At my age, my eyesight isn't what it used to be! :laughing7: (square grating is aka cat walk) Love the walkways over the pontoons. Could load up my coolers, camping gear for a extended dredge trip down river!
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Im jealous your actually getting to build one and have a place to use it. Yes the jet, front and back of sluice are adjustable to tune it in and bring it out of water for moving. That hand winch operates the front of sluice so you can easily adjust sluice pitch depending how hard you are running material (flows). Good luck. I started with the motor/pump/jet Had i to do it again i would have used twin engines The dredge broke down for a one man show but that 18hp Briggs was a mite heavy. Twin 11 hp Hondas woulda been better.
 

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Hey guys sorry i've been away fighting the greenies in maine. I just wanted to chime in a bit about some of the talk about jet's and volume. By having a more efficient jet like a infinity jet gives you the option to make a choice on how you want to run. You could run a smaller motor and smaller sluicebox because the total volume is going to be lower supplied to the sluice when compared directly to the same suction level from a log jet. You can run the same size dredge/motor designed for a log jet and benefit from the increased suction volume to run the box volume at the proper rate. You can also add extra length to the suction hose and adjust as needed. It is the decision that determines the design.

"P" is right in addressing the material to wash water ratio. This will change and may take a little time in the learning curve, but I wouldn't expect it to make too much difference as long as the box volume is running properly.
 

Timberdoodle said:
Hey guys sorry i've been away fighting the greenies in maine. I just wanted to chime in a bit about some of the talk about jet's and volume. By having a more efficient jet like a infinity jet gives you the option to make a choice on how you want to run. You could run a smaller motor and smaller sluicebox because the total volume is going to be lower supplied to the sluice when compared directly to the same suction level from a log jet. You can run the same size dredge/motor designed for a log jet and benefit from the increased suction volume to run the box volume at the proper rate. You can also add extra length to the suction hose and adjust as needed. It is the decision that determines the design. "P" is right in addressing the material to wash water ratio. This will change and may take a little time in the learning curve, but I wouldn't expect it to make too much difference as long as the box volume is running properly.
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Bigger box & bigger volume = higher YPH right ?
 

Yes more YPH. It is more of a question of whether you want to run more YPH or build a smaller lighter dredge with similar YPH to an existing larger design. Everything you mentioned about smaller box. smaller flare, etc.. would play into the equation if wanting to build a smaller dredge that is easier to carry in but still capable of moving larger material.
 

Timberdoodle said:
Yes more YPH. It is more of a question of whether you want to run more YPH or build a smaller lighter dredge with similar YPH to an existing larger design. Everything you mentioned about smaller box. smaller flare, etc.. would play into the equation if wanting to build a smaller dredge that is easier to carry in but still capable of moving larger material.
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I thought about it the other day but i dont know if i was right but i figured that even if you get the same draw with less engine with a more efficient jet ; you wont be able to feed the same kind of material as with a normal jet that applys more water to the sluice. I think if you use the same gpm used on a log jet to push a infinity jet than you will get a huge suction but still will have keep up with the lower feed rates, but still achieving to move at least DOUBLE the YPH what a normal jet moves. Does it sound right?
 

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G1, yes, the law of fluid dynamics and physics. You take a fluid like water, its fairly dense inside like a suction tube. The tube will not expand or contract, neither will the water unless its being compressed. Now if you induce a flow of water into this tube (venturi)the water will start to move. If you keep in mind that nothing is going to expand or contract, the volume of water will remain the same. The ONLY thing that will change is the velocity. Venturi's work by pressure differential. The water after the jet increases in speed, physics dictate the water behind the jet (suction) will also speed up. Being water and material is not very compressible, the speed or the water is the only thing that can change to fill in the void. Like sucking through a straw. if you suck slowly you get a little, if you suck hard, it flows faster.

I know I'm not articulating well what I'm trying to say, but I do remember from the fluid dynamics class I had to take for hydraulics and advance hydraulics. If you use a small pump to start the flow, yes it will work due to the higher efficiency, but you'll have a lower velocity, unless you run it wide out. If you use the proper sized pump and motor, you will have a greater flow (velocity) while using less rpms.
 

G, I'm not arguing here.
But engine speed equals pump speed which controls water volume and pressure. As pressure increases, volume drops and velocity increases. Having 360 degrees of jet surface equals more surface area for the stream to act against, thus it increases efficiency. It's easier to push a car with 2 hands then 1 hand and its easier to push a car with your shoulder then 2 hands. After the water is moving, this is where velocity kicks in. The speed of the jet will cause more of a pressure differential in front causing more negative pressure behind. Being water isn't expandable and the hose doesn't decrease in size, to fill in the "void" it flows faster. Being the measurements we care about are in how much material we can move, the more water flow we have through the jet, the more material we move via suction.
 

God I don't remember everything about fluid dynamics. I will freely admit that. Hell I could be wrong about everything!
 

principedeleon said:
I thought about it the other day but i dont know if i was right but i figured that even if you get the same draw with less engine with a more efficient jet ; you wont be able to feed the same kind of material as with a normal jet that applys more water to the sluice. I think if you use the same gpm used on a log jet to push a infinity jet than you will get a huge suction but still will have keep up with the lower feed rates, but still achieving to move at least DOUBLE the YPH what a normal jet moves. Does it sound right?
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yes, An infinity jet or any jet that is more efficient used on the same motor will result in more capable throughput and YPH.

I think the points are good that are being made. I just want to clarify that when comparing apples to apples on 2 jets. Lets say we have 2 jets that we want to run both at a specific suction level (30inches of water measured with a manometer). The more efficient jet will produce the necessary suction with less volume needed(built or adjusted with smaller orifice). The end result is the total output to the box will be less than the less efficient jet.

Another view
If the orifice sizes are the same then equal volume delivery from the jets is the same and total volume would increase to the box due to the increased suction from the more efficient jet. Sound good?
 

Timberdoodle said:
yes, An infinity jet or any jet that is more efficient used on the same motor will result in more capable throughput and YPH. I think the points are good that are being made. I just want to clarify that when comparing apples to apples on 2 jets. Lets say we have 2 jets that we want to run both at a specific suction level (30inches of water measured with a manometer). The more efficient jet will produce the necessary suction with less volume needed(built or adjusted with smaller orifice). The end result is the total output to the box will be less than the less efficient jet. Another view If the orifice sizes are the same then equal volume delivery from the jets is the same and total volume would increase to the box due to the increased suction from the more efficient jet. Sound good?
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Sounds simple and easy to understand. So less water mean less material that could be feed through the box. Even if you have that 30 inches of water in suction. You could get away and use a smaller engine and achieve the same amount of water needed via suction to replace the low water input. But you would have to run it just like the other pump running the jet log for you can get the same gpm output to the sluice box.

Meaning you will be able to move the SAME YPH with a smaller pump.
 

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G1sammons said:
Unless you drop to a smaller engine. And pump you should never have less water with a more efficient jet..
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Im comparing two jets both at the same suction. When you do so the infinity will run the same suction and will need less water. So if you sum the gpm of input to the infinity + the same suction draw you end up with less water to the sluice box.
 

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