Rotating Sparge Arm

[swampdonkeybeer]

Hello everyone,

This is a quick rundown of how I put together a rotating sparge arm for my home brewery. This is a bit difficult to explain, but I hope with the pictures added to the description everything will be fairly clear.

Cheers,
Benjamin

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The Goal: Here is a pic of the completed project. The only thing not shown is the little rubber caps I picked up at a local hardware store to close up the ends of the rotating arm itself.

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Step 1) The first thing we need is some brass tubing of various size diameters.

1a) We need a lower arm assembly comprised of two tubes (eventually soldered) forming a "T" shape.

1b) We need a tube sleeve (middle tube) that is just slightly larger in diameter than the lower assemblies vertical tube.

1c) We need another tube that is just barely larger than the middle tube to make retention rings with

1d) we need a long and larger diameter tube than the other tubes that is the final exterior vertical tube.

Here you can see the rotating part of the lower arm with a hole already drilled to accept the vertical tube.

Step 2) We need a vertical tube on the lower assembly and a bearing surface. What you need to know now is that there are two parts to the vertical tube. There are two tubes that fit inside each other perfectly. The inner tube is the one permanently fixed to the lower rotating arm itself (gonna plug into that hole in the lower arm you just saw above). The outer tube is just a sleeve that fits over the lower assembly arms vertical tube. This needs to be a snug fit but without any friction. Polish the inside of the sleeve and the outside of the lower assembly until they slide in and out of each other perfectly.

Bearing Surface? - If you cut a ring off from the middle tube here (maybe 1/4" length) and solder it to the top of the vertical tube from the lower assembly, what you end up with is a lip for the lower assembly to rest on as it dangles inside the bigger diameter tube.

Here is a couple pictures of these two tubes and the bearing surface ring at the top of the smaller tube. This should give you an idea of what I am talking about. It is very important to understand that this is the bearing surface from which the mechanism rotates. You absolutely need to have the bottom side of the ring and the top edge of the middle tube perfectly flat to each other. Because they rest against each other and because this is where the mechanism spins, you have to minimize friction by having them perfect. Take the time here to either cut the with precision or to sand the pieces and polish them extremely smooth.


Here is the middle tube sleeve already over the lower assembly vertical tube. The bearing ring is already fixed to the lower assembly.

Here is the same shot but with the two tubes sitting together on the bearing surface.

Step 3) Now that the bearing surface is fixed to the lower assembly vertical tube, we need to address the middle tube sleeve. The tube that is just a little bigger than the middle tube here needs to be cut into rings. These rings are going to be fixed to the outside of the middle ring with spaces between them. These spaces are for rubber rings to sit in.

Here are the retention rings.

Here are the rings loosely fit over the middle tube and spaced out a little.

Here we are soldering those rings into the final placement and spacing.

Here are the rubber rings that fit over the middle tube.

Here is the middle tube with the retention rings and the rubber rings on it. It is sitting in-place around the lower assembly. The lower assembly horizontal tube is held in place here as well.

Step 4) Not that all those moving parts are soldered together and the middle tube is in place, the lower assembly can be soldered into final position. This forms the "T" shape at the bottom.

Here is the lower assembly soldered together. The middle tube is now trapped between the lower assembly and the bearing surface ring.

Step 5) The outside vertical tube can now be friction fit into place here. It is large enough that it slides over the top of those rubber rings and holds very snug. It shouldn't be so tight that it is difficult to put together, but it should be snug.

The lower assembly needs holes in now. I started with very small holes spaced evenly across the lower arm. The holes along each side of the lower arm (on either side of the vertical tubes) need to be along the sides of the tube and on opposed sides end for end. Think water sprinkler here.

In this picture you can see the outside vertical tube in place and you can see the holes in the lower assembly on the left side. The right side holes are of course in the exact same position but on the other side of the tube.

note: You will need a couple rubber stoppers or caps to stop up the ends of the lower assembly. You could solder the thing closed with little discs of metal or something, but I want to be able to run a pipe cleaner through this thing once and a while.

note: I added a couple extra holes toward the outside of the lower arm. More water exiting that tube on the outsides helps the spinning action. I recommend starting small with the holes and run a little water from the tap trough the thing to see how fast the flow is. You want it to spin easily and to not dump too much water all at once.

Step 6) The sparge. I drilled a hole in a large cutting board thats just big enough that the outer vertical tube fits in there. I used some additional rubber rings to hold the tube in place on the cutting board. The cutting board also acts as a lid (for the most part) on the mash tun to keep that heat in there.

In this photo you can see the sparge arm in action. It is in place in the cutting board, dangling just a few inches above the top of the grain. Sparge water is being gravity fed to the sparge arm via my second mash tun / lauter tun. The BK is seen below collecting that sweet sweet liquid!

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I hope all of this makes sense. There are a bunch of little parts and doodads, but ultimately it is a very simple mechanism. I adjust the water pressure with a ball valve and only use gravity to feed the sparge arm. I generally get a 60-90 minute time frame on the sparge.

 

[Bobby_M]

You've done an amazing job of making this thing but I have to ask why there is still a fascination with this type of sparge delivery. If you maintain a foundation of 1-2" of water over the top of the grain bed, the method of delivering new water is of no consequence.

 

[swampdonkeybeer]

Its because I can. When I was a kid... playing in a hose wasn't fun unless the sprinkler was attached.

LOL

It just looks cool. Thats all.


Sent from my iPhone using Home Brew

 

[HiImBrian]

Your pictures no longer work, but I don't want to create yet another rotating sparge thread. My question is...

What the heck kind of fitting is this?! I can't seem to find anything like this at Home Depot and the people there think I'm an idiot for asking for something that can rotate like this. From what I've read, it sounds like this fitting is not meant to rotate, but it's loaded up with thread tape and not tightened down completely. This still doesn't tell me what sort of fitting it is though. Any ideas or thoughts?

 

[dirkomatic]

Just guessing... A compression fitting which is bored all the way through?

 

[HiImBrian]

Just guessing... A compression fitting which is bored all the way through?

So something like this?
http://www.homedepot.com/p/Watts-1-...n-x-MIP-Adapter-with-Insert-LF-A221/202254875
What I can't figure out is how the copper pipe stays connected to the fitting.

Only thing I can think of to make this work is a push fitting like this. But I'm very curious how they did it in the above picture.
http://www.homedepot.com/p/Cash-Acme-1-2-in-Copper-Push-to-Connect-Coupling-C008LFA/205440746

 

[dirkomatic]

I really think you need the original pictures with the original text to figure out how it was all put together... Or at least I do. I think there's some soldering going on which isn't obvious by just reading the text.

But, truthfully, I'm in full agreement with Bobby. This is kind of an archaic minded contraption. Just put an inch of water on top of the grain bed and go with it. No need of a sprayer or rotating arm...

 

[swampdonkeybeer]

Sorry the pictures are broken now. I'll see if I can just draw a quick diagram to explain the fitting I built. Maybe dig up a couple of the original photos too.

 

[swampdonkeybeer]

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this is a quick and dirty explanation of the rotating sparge arm I built.

There are three tubes involved. The overall main shaft (seen in diag C) is the largest tube and is not altered other than cut to the length you want. It is also the largest diameter tube.

The second tube is a bearing tube(Diag B). It is a little smaller than the main shaft (diag C) to accommodate for silicone o-rings which are spaced and held from sliding by (technically a fourth tube) sections of a tube that just barely fit around the bearing tube. These sections are soldered into place. The o-rings settle into the spaces between these sections. The o-rings function to hold the bearing tube onto the inside of the main shaft (see Diag C). When inserted into the main shaft, the bearing tube with the o-rings in place will friction fit snugly and will not be able to slide up and down easily. this also stops water flow from bypassing the bearing tube.

The third tube (diag A) is comprised of a few parts. The sparg wand itself (with small holes drilled on each but opposite sides to make it rotate when water flows). the drop tube, which is soldered to the wand and forms a "T" shape. The bearing ring, which is a small section cut from the bearing tube (diag B) and is soldered to the outside of the drop tube. the drop tube fits exactly into the bearing tube but is able to move freely without friction.

When assembling the whole thing... Make the bearing tube first (diag B). Then make the bottom half of the wand (diag A) without the bearing ring soldered on yet. Pass the drop tube up through the bearing tube (remember it should just barely but easily fit). When it exits the top of the bearing tube, solder the bearing ring to the top of the drop tube. these parts are now permanently fixed together. When you now let the drop tube go, the bearing ring sits just on top of the bearing tube and holds the rest of the drop tube assembly from falling out again. An important note here is that the top of the bearing tube and the bottom of the bearing ring (diag B) are always in contact with each other and is the primary weight bearing area. It is important that both of those surfaces are polished perfectly smooth so as to minimize friction. This is where the drop tube spins but the bearing tube remains still.

After the parts from Diag-A and Diag-B are put together, the whole thing just friction fits up into the main shaft.

Add end caps to the wand ends.

Clamp a water hose to the top of the main shaft.

You are done.

You'll need to do something to hold the whole thing vertical when sparging. I drilled a hole in a cutting board that fit over my mash tun like a lid (because I didn't want a hole in my actual mash tun lid). I used large o-rings to hold it at the depth I wanted it.

 

[swampdonkeybeer]

Please keep in mind that the drawings are messy and not to any kind of scale. I will try to answer questions as best as I can.

 

[swampdonkeybeer]

Aside from it looking great, I find that my overall efficiency is better when I take the proper time to sparge using the rotating arm. I think the slow and controlled continuous downward trickle of sparge water helps to wash more of the sugars from the grain. Just having a tube dropped on top and flooding the mash tun works great and is faster. A batch sparge is even easier and faster still. I do however feel that efficiency is effected depending on what you do. My two cents anyway.

 

[Bobby_M]

Flooding the tun to at least an inch over the grain actually is the way you do a proper fly sparge and in that case, the water delivery method only needs to be gentle enough to not bore down into the grain bed. A rotating sparge arm does that fine as does a static sprinkling manifold or a well placed hose. If you happen to run your tun too dry with the top of the grain exposed, then yes a rotating arm will increase efficiency. That would be more like fixing a problem that didn't need to be a problem.

 

[swampdonkeybeer]

Gotcha. Well, either way it definitely looks cool while in use. I'm glad I built it. A fun project for diy nerds like me.

 

[HiImBrian]

I ended up going a different route simply due to the whole KISS method. Because I wanted to be able to sparge with my MLT lid on to maintain temp better, I didn't want to risk a rotating arm getting stuck somehow without me knowing it. I've also opted to use a 20" stem thermometer sticking down through the lid of my MLT to maintain temps, and this would not be possible with a rotating arm. If in fact I would be able to see the sparge arm, then I would hands down do a rotating assembly for the sole purpose of having something that looks cool! I ended up curling 15' of 3/8" copper tubing into the lid of my MLT. The tubing is permanently fixed to the lid and makes for a very easy hook up and go. I'll post a picture once I finish drilling holes.

Thanks OP for posting those pictures and a write up!