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Drywasher question


Bedrock Bob

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Wbich way does the fan in your air blown drywasher turn???

Is one way better than the other?

Do the fans on Australian drywashers turn backward??

I was making a new one from sheet metal and had always made them counter clockwise . That is the natural way they bend using a pair of right handed shears.

So does anyone know which way is best??? CW or CCW??

Edited by Bedrock Bob
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I guess I should have provided more detail for the mechanically challenged prospectors here. I am speaking about the fan on the counterweight and not the blower impeller mounted on the engine output shaft.

The fan will turn either direction depending on which direction the blades are angled. If you use right handed shears you get CCW rotation, left handed shears you get CW rotation.

Edited by Bedrock Bob
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Hmmmmm I have never even pondered on this question, but I am a puffer guy. Can't imagine much difference with the fan, but reversing the motor on my Keene Puffer makes a big difference in operation and has it's applications depending on the dirt being run as well as moisture content.

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MY opinion would be to try mounting it both ways, and run a

few buckets each way to see what works best for you.

On the same subject, have been thinking about installing a

variable speed fan switch and running different speeds to see

if any improvement.

Has anyone tried this, & what results????

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The fan speed and vibration on mine is adjustable by running the counterweight in and out from the axis. A slow vibration is best but it depends on your material... you gotta make it dance.

Since CFM makes no difference in a drywasher but static pressure does there is a sweet spot to every impeller design. Slower or faster RPM and you have problems lifting the material off the table. That is why vibration should be afjusted at the counterweight and not by the speed of the engine or impeller. I do know this is the case by testing. Especially when using a leaf blower with helical vanes. They will only provide the required static pressure at full RPM so there is very little you can do with impeller speeds and airflow. With an industrial type high static blower designed to move material you have great pressure to lift msterial at much lower RPM/CFM so your engine runs much slower and you don't need all that air. Your vibration is slower and your lift is better with less air so you wind up getting more fine gold.

Edited by Bedrock Bob
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On my 140, looking down at the fan it spins clockwise. Judging by the fan blades it isn't necessarily blowing up per say, rather it appears that the air is simply blown into the box in a circular motion. All you need is air going to the least resistance i.e. riffle cloth & tray, and the counterweight for the vibration. Notice how when the riffle tray is being primed with material that the air finally seems to even out when all the trays finally have material in them. You wouldn't even need the fan if there was some other way to vibrate the box

If North was up then my post is directly South of yours.

Edited by adam
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On my 140, looking down at the fan it spins clockwise. Judging by the fan blades it isn't necessarily blowing up per say, rather it appears that the air is simply blown into the box in a circular motion. All you need is air going to the least resistance i.e. riffle cloth & tray, and the counterweight for the vibration. Notice how when the riffle tray is being primed with material that the air finally seems to even out when all the trays finally have material in them. You wouldn't even need the fan if there was some other way to vibrate the box

If North was up then my post is directly South of yours.

It is funny that the Keene turns the other way.

I was not saying the direction of the fan had to do with the direction of the air but the direction of the vibration. I have seen drywasheers that used a counterweight on a squirrel cage mounted on aa horizontal axis. So yeah, it may not make any difference. But since every other natural spin (on a vertical axis) is CW above the equator and CCW below it seems there may be a preference.

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Hey i got it wrong again. My fan spins CW too. But the question is the same....Is there. a difference???

I notice thosr bagless vacuums that concentrate in a vortex do too.... hmmmmm.....

When I finish a pan I always use a CCW spin to seperate gold from black sand. It may just be my left handedness but it seems to make a big difference in the way the particles act.

I know for sure the CW spin puts gold on the right end of the riffles and a CCW spin drops it on the other side. And when a puffer gets loaded up and sluggish a quick turn in the opposite direction will get things moving again. The direction of that vibration is bound to be a factor in efficiency somehow...

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