Saw this sluice at the local gold show last week....

[arizau]

GPD - Pascal's Principle only relates to contained fluids as shown in this picture:

View attachment 1196305

As pressure is applied on one end the pressure travels through the fluid at the same pressure to the other end.

Stream flows are not contained and pressure cannot be exerted so Pascal's Principal does not apply. Stream flows actually have literally no pressure because in they exposed to the atmosphere therefore they can have no pressure above atmospheric. Since flows are entering the machine at virtually zero and water cannot be compressed the pressure within any machine remains at zero (+ that extremely minute atmospheric pressure). This goes back to why I chose velocity and exacting flow. The design of the plenums actually increases the water velocity and since the volume is the same over its entire length the flows through each hole are exactly the same.

Did you forget that head pressure is generated by the weight/speed of the water trying to pass through the main openings? The pressure does equalize throughout no matter the speed but that pressure, head pressure, varies dependent on stream speed and speed through the jets will also vary accordingly. The pressure is actually at it's lowest point as it goes through the jets but the speed goes up with increased head pressure. https://www.google.com/search?q=ven...0.11011j0j4&sourceid=chrome&es_sm=93&ie=UTF-8

The same principle applies to a traditional bazooka. I am pretty sure that my overall science is correct but I am open to correction.

Good luck in your enterprise.

 

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[AMP_kbell]

arizau - man you guys are working my feeble mind way too much!!!

you are talking about head pressure and the link you cited talks about the venturi effect.

Remember I cited stream flow pressure as being zero.

Head pressure is calculation of height of water falling to create pressure. One foot of head (height) will generate .43 psi. one inch of head has .0358 psi (.43/12). Realize both the BGT and my machines are under water about 2 + inches. That calculates to a negative .072 psi (.43/-6). Really it is zero since you can't generate negative pressure per se.

The Venturi Effect on the other hand is the means by which I generate additional velocity in my plenums (vents). If you look at the plenum in relation to the rear of the machine it forms an hour glass shape (plenum is larger in front of the machine, much smaller in the rear, then opens back into the relatively infinite stream flow. The water enters the plenum at x speed and then is accelerated down the plenum at x + area of the plenum.

When I say that using a rock upstream of the machine to regulate the water flow on the material tray doesn't affect the plenums it is because they are generating their own velocity!

 

[AMP_kbell]

I wanted to let everyone on this thread that I created a new thread called Aurora Mining Products Fluid Bed Sluice Test. If you are interested in trying out the machines go to that post and check it out. Requests, reviews and comments will be posted there. I will be sending out the first Expedition fixed machines to KevininColorado and Duckwalk. They will be the first to comment. I will be leaving for North Carolina this Saturday and will return Sunday August 16th. I will monitor the thread. mike(swWash) make sure you get your name on the list - you started this!!!

 

[GoldpannerDave]

GPD - Pascal's Principle only relates to contained fluids as shown in this picture:

View attachment 1196305

As pressure is applied on one end the pressure travels through the fluid at the same pressure to the other end.

Stream flows are not contained and pressure cannot be exerted so Pascal's Principal does not apply. Stream flows actually have literally no pressure because in they exposed to the atmosphere therefore they can have no pressure above atmospheric. Since flows are entering the machine at virtually zero and water cannot be compressed the pressure within any machine remains at zero (+ that extremely minute atmospheric pressure). This goes back to why I chose velocity and exacting flow. The design of the plenums actually increases the water velocity and since the volume is the same over its entire length the flows through each hole are exactly the same.

Like I said, I could be wrong, but the water in the lower chamber is basically confined, so that is why I think Pascal applies.

And I was not talking about vertical pressure, as in water towers, but pressure from flowing fluids.

 

[AMP_kbell]

Pascal's theory talks about a confined area, i.e. one that is capped with no leaks. That is the only way that pressure can be generated and transferred.

For instance if you have a hydraulic ram that can lift a car and it has a large leak then it cannot hold the car up - it will slowly drop as the fluid leaks out. If the leak is significant then it can't even lift the car up.

Since there are several spaced holes in the tubes (the sum of which matches or possibly even exceeds the volume in the tube) you can have no pressure or transfer of pressure. Let's say the pipe in the BGT is 6 inches long and 1/2" - you have about 1.18 cubic inches of volume. If you have two rows of five evenly spaced 1/8" holes you would have a total 1.25" of hole in that same 1/2" diameter pipe. Since the holes can release the entire volume of the pipe you can have no pressure.

 

[GoldpannerDave]

Pascal's theory talks about a confined area, i.e. one that is capped with no leaks. That is the only way that pressure can be generated and transferred.

For instance if you have a hydraulic ram that can lift a car and it has a large leak then it cannot hold the car up - it will slowly drop as the fluid leaks out. If the leak is significant then it can't even lift the car up.

Since there are several spaced holes in the tubes (the sum of which matches or possibly even exceeds the volume in the tube) you can have no pressure or transfer of pressure. Let's say the pipe in the BGT is 6 inches long and 1/2" - you have about 1.18 cubic inches of volume. If you have two rows of five evenly spaced 1/8" holes you would have a total 1.25" of hole in that same 1/2" diameter pipe. Since the holes can release the entire volume of the pipe you can have no pressure.

While I am a chemist, not a physicist or a hydrologist, I do understand that a calculus approach still works. By that I mean, as you move away from the perfect condition, you still have pressure transmitted. The further from the perfect condition, the less pressure transmitted. You are correct, with significant leaks, the car lift won't work. But with small leaks it does. I have a floor jack with a small leak. It will jack the car up to a certain point; much higher than you might think. Then I put a jack stand under it. But if I keep pumping the jack handle, the system still transmits the pressure, but not perfectly, but it will hold up the car at that point.

However, while theory is great, experimental data is better. Hence, testing your sluice. Like KevinInColorado and others, I want to see the results from field testing (not just laboratory testing). I also love to see advances. Instead of arguing about it, why not test it? Which we're going to do. "If it works, it ain't dumb" or "the proof of the pudding is in the eating" are both ways folks have expressed using the experimental approach in real life.

Reminds me of the theoretical physicists going to a convention in England about 100 years ago. They were sitting in the train, discussing various topics of interest when the train slammed to a stop. One said, "Let's go see what happened!" Another one said, "Sit down; we are theoretical physicists--let's theorize about what happened."

The only reason that is funny is that it is (1) backwards to real life and (2) perhaps it does caricature theoretical physicists pretty well.

"So, let the games begin."

 

[KevinInColorado]

As an engineer (Manufacturing Engineering at Michigan State), I'm all about what works! The British Engineers say "Suck it and see!" So that's what we'll do!

Means to try something out under normal circumstances without judging based on your biases. Origin:
British expression referring to trying out something untested or kind of unknown. It's really a metaphor - the new thing is like a piece of hard candy, the uknown consequences are the flavour, so you "suck it and see"!

 

[arizau]

arizau - man you guys are working my feeble mind way too much!!!

you are talking about head pressure and the link you cited talks about the venturi effect.

Remember I cited stream flow pressure as being zero.

Head pressure is calculation of height of water falling to create pressure. One foot of head (height) will generate .43 psi. one inch of head has .0358 psi (.43/12). Realize both the BGT and my machines are under water about 2 + inches. That calculates to a negative .072 psi (.43/-6). Really it is zero since you can't generate negative pressure per se.

The Venturi Effect on the other hand is the means by which I generate additional velocity in my plenums (vents). If you look at the plenum in relation to the rear of the machine it forms an hour glass shape (plenum is larger in front of the machine, much smaller in the rear, then opens back into the relatively infinite stream flow. The water enters the plenum at x speed and then is accelerated down the plenum at x + area of the plenum.

When I say that using a rock upstream of the machine to regulate the water flow on the material tray doesn't affect the plenums it is because they are generating their own velocity!

The term I probably should have used is kinetic energy or maybe dynamic pressure both of which will change with stream speed changes.

The reference is to show how speed is increased as it passes through an orfice/jet and refers to the preceding sentence.

 

[arizau]

Pascal's theory talks about a confined area, i.e. one that is capped with no leaks. That is the only way that pressure can be generated and transferred.

For instance if you have a hydraulic ram that can lift a car and it has a large leak then it cannot hold the car up - it will slowly drop as the fluid leaks out. If the leak is significant then it can't even lift the car up.

Since there are several spaced holes in the tubes (the sum of which matches or possibly even exceeds the volume in the tube) you can have no pressure or transfer of pressure. Let's say the pipe in the BGT is 6 inches long and 1/2" - you have about 1.18 cubic inches of volume. If you have two rows of five evenly spaced 1/8" holes you would have a total 1.25" of hole in that same 1/2" diameter pipe. Since the holes can release the entire volume of the pipe you can have no pressure.

This is not meant in a negative way and I wish you all success but your example calculation is off by a factor of about 10. The area of 10, 1/8" holes is 0.123 square inches. The area of the opening for the supply tube (1/2") is 0.196 square inches.

I too am interested in field test reports.

Good luck