Very interesting whirlpool video

[SDBob]

[ame]https://www.youtube.com/watch?v=DV87i-DbNo8[/ame]

A few curiosities here I'm having trouble wrapping my head around. They start spinning the shaft in a clockwise that forces the paddles to an almost 90 degree angle which get the mass spinning rather quickly, then reverse rotation of the shaft. This flips the paddles to an almost zero degree angle and reverses the whirlpool. The zero degree angle allows them to stop the shaft without the paddles disturbing the whirlpool.
But why the initial clockwise rotation? Are the zero degree paddles given an advantage by initially rotating against a spinning mass? Seems pointless on the surface, but there's clearly a reason.

Additionally, note the stationary and seemingly purposeless paddle of similar design attached to the right side of the kettle. It flops one way during the clockwise rotation, then flips as the mass of fluid changes direction. WHY??

I've watched this video 47,000 times and can't for the life of me figure it out.

 

[ChefRex]

I would think they spun it backwards to get the matter into suspension, if they spun it forward most would have stayed where it was.
Apparently the colors are different weights as most of the yellow remains in the bottom.

 

[itsnotrequired]

started in opposite direction to get the material in random suspension.

 

[Resonator]

Also the paddle to the side creates a disturbance in the flow, and pushes things to the middle instead of allowing them to stick to the sides

 

[SDBob]

Makes sense... I may just get crazy and try to duplicate that.

 

[passedpawn]

From the webz (this is a description of a different video, below, but it's for the same device):

step 1: from beginning to 1'03" we are simulating boiling.Agitation is very heavy, paddle is turning clockwise and racks have an angle of 45 degrees.

step 2: from 1'04 to 2'38" we are simulating what happen during whirlpool. Solid parts are receiving speed io order to fall down when this speed will suddenly cease. Paddle is turning counterclockwise and racks are flat.

step 3: from 2'39" to the end solids parts are all falling towards the center, that is what we expect.


​

 

[SDBob]

Ah ha.
And I found this at yet another site:
The DUPLEX sits at 45 degrees for an adequate mixing of the wort, while rotating in the opposite direction, placing them horizontally in order to have a paddle whirlpool. The paddles’ rotation is automatic and takes place only because fluid dynamics forces the effect. In this way, at the end of the boiling, by just reversing the paddle rotation, it is possible to perform a fast and efficient whirlpool, without transferring the wort into a specific tank.

So they're not just simulating a boil, they actually mix the wort with that paddle during the boil. At flameout they reverse the rotation for whirlpool.

The side paddle creates turbulence during the boil and folds away during whirlpool.

Damn... Thanks guys!

 

[govner1]

Great concept but my concern would be hot side aeration given the speed of the rotation.

 

[IslandLizard]

I love it! I want one of those!

 

[jpc]

Apparently the colors are different weights as most of the yellow remains in the bottom.

Hmmm... I thought it was candy corn...

Maybe I just have sugar on the brain.

 

[SDBob]

Great concept but my concern would be hot side aeration given the speed of the rotation.

Are you talking about the 30 seconds of whirlpool at 75 RPM or constantly stirring the wort during boil at 75 RPM? If I end up fabbing a paddle like this, I was thinking of programming that stir for 30 seconds every ten minutes, but at a lower rpm. And I'm totally shooting from the hip here.

 

[matc]

hot side aeration is a myth anyway plus in the video, there's no splashing at all