Interesting idea for a rotating sparge arm

1. I apologize if this is posted in the wrong forum.
2. I batch sparge so perhaps this exact method has already been done.



This is basically a sparge type arm that was created for cooling a swimming pool. I found it interesting how he drilled through the center of the "+" to feed the water to each of the 4 arms.

I just have to wonder how low the water pressure can be to still spin. I am also curious to the amount of water that drips down the middle.
http://davidwilbur.com/index.php?q=gallery&g2_itemId=108

I did a bit of a search on HBT but didn't find anything along these lines.

Pretty much the same thing as a "Phil's Sparge Arm", but bigger pieces.

There will be water dribbling down through the middle part, but water flows where the least resistance is, so most of the water will go to the long arms with the holes drilled in it.

Doesn't look like it would spin at all to me and I am curious as to the purpose of the holes in the down tube part. Seems that unless there were some kind of very low friction bearing surface for the thing to ride on that it would not spin very well. OTOH, the "jets" (small holes in the arms) will produce more thrust than you might imagine. Think lawn sprinkler. Matter of fact, I'm not clear on why he would not simply use a lawn sprinkler for this in the first place.

Never mind, I see that the arms are lifted to show the holes and that's not the position they would be in while it's operating. A teflon washer might reduce the friction considerably. Might not be needed though. It must work or he would likely not have posted the pics.

They have a pool pump powering that thing - That's a LOT more pressure than we need for sparging...

I doubt our flow rates would make it rotate if you put bearings in the center

Neat idea though! Let us know if it works!

SweetSounds said:

They have a pool pump powering that thing - That's a LOT more pressure than we need for sparging...

I doubt our flow rates would make it rotate if you put bearings in the center

Neat idea though! Let us know if it works!

Click to expand...

I think that some water squeezes downward past the vertical tube and functions as a fluid bearing between the cross and the end cap. The arms sort of "ride" on the water cushion. Lot's of rotating sprinklers work on a similar principle. I do agree that it would require way to much water to make it turn so it would not be very practical on our small scale breweries. The real bottom line is that a rotating sparge arm is not at all necessary. I used one for many years, but eventually went with a simple non-rotating manifold instead.

I have tried a "Phil's Sparge Arm". Other than not really being needed, a problem I found is unless you have a fairly high flow rate, if it is not sitting pretty darn level, the water will flow into the "lowest" arm and it won't spin.