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Part 6 - Cooling tray
David
Top  #41 Print Post
Posted on 02/13/2008 12:01 PM
Here we go!

The Cooler Prototype Test

I rounded up a 14' cheesecake pan and a couple of different pizza screen and set out to test our concept with the Mini Leaf Blower.

I carved a 14" hole in a cardboard box and inserted the cheesecake pan into it. I attached the Mini Leaf Blower to the side of the box and tested it. It backed it self out immediately (coolus interruptus?).
David attached the following image:
k02[756].jpg
 
David
Top  #42 Print Post
Posted on 02/13/2008 12:03 PM
With its mandatory seatbelt now in place, the first actual test was to check its power against the solid disk which served as the pan's removable bottom. It lifted it almost an inch.
David attached the following image:
k03[757].jpg
 
David
Top  #43 Print Post
Posted on 02/13/2008 12:05 PM
Next was the pizza "Mega" screen, a perforated disk the same size as the original bottom. It didn't lift up, but neither did it pass very much air though.
David attached the following image:
k04[759].jpg
 
David
Top  #44 Print Post
Posted on 02/13/2008 12:07 PM
Finally, the pizza screen itself. You can see by the size of the openimgs that the wires do not block much of the air, mmm, maybe 20% or so. There was a half-inch space between the outer edge of the 13" pizza screen and the 14" cheesecake pan. I thought it might be a "dead" space that the stirring mechanism would have to deal with.
David attached the following image:
k05[760].jpg
 
David
Top  #45 Print Post
Posted on 02/13/2008 12:15 PM
2 lbs. 8 oz. of Brazil Monte Carlo were roasted to Full City and poured into the cooler on top of the waiting thermocouple. I turned on the timer, the blower, and my camera. I didn't get a readable shot of the initial temperature.

However, as the pictures show, the temperature was down to 163F after a mere 47 seconds. And, at a full minute the temperature was down to 142F [blurry picture available on request] and I found that I was able to stir the beans with my bare fingers. There were some warmer beans around the outer edges where the air could not flow through, but they were not "hot."
David attached the following image:
k06[763].jpg
 
David
Top  #46 Print Post
Posted on 02/13/2008 12:30 PM
The temperature was down to 90F after 2 minutes.
It hit 79F by the third minute and 75F at the four minute mark.
David attached the following image:
Temps[764].jpg
 
David
Top  #47 Print Post
Posted on 02/13/2008 12:34 PM
The final weight of the cooled beans was 2 lbs. 2.25 oz. I think that's about an ounce shy of a full kilo.

So, my conclusion is that the arrangement as tested is quite sufficient to cool at least a kilogram of roasted beans for the Zen 4.2 roaster.
David attached the following image:
k12[765].jpg
 
David
Top  #48 Print Post
Posted on 02/13/2008 12:45 PM
BTW and FWIW --

After weighing the beans I poured them into the 12"x2" cheesecake pan that we had initially thought we could use. The picture shows the comparison 12x2 to 14x3. I think we did well to go with both the increased depth and increased diameter.

Your comments?
David attached the following image:
k11[766].jpg
 
Alchemist
Top  #49 Print Post
Posted on 02/13/2008 1:43 PM
Comments - GREAT!

BTW - to those entered in the cooler competition, THIS kind of time vs temp style data would be great (hint hint hint says one of the judges ;) )

You are very right - I am very glad we moved to the 14" x 3" pan and pizza tray.

Would you verify something for me please? The cake pan is nominally 14". Is that inner or outer diameter? Either way, can you give me the outer diameter (circumference / 3.14159) to say 1/16"? Likewise, is the depth exactly 3"? And while you have that tape measure out, what is the depth from bottom to the bottom of the edge curl?
 
David
Top  #50 Print Post
Posted on 02/19/2008 4:11 PM
Ah, yes, the measurements.

I had noticed earlier that the disk had plenty of room at the top, but snugged up as it went to the bottom. Clearly there was a taper, but didn't actually measure it.

So, 14" is the OD at the bottom.
14 3/16th is the ID at the top and the metal is about 1 mm thick.

From the bottom of the pan it is 3 3/4" to the bottom of the curl.
 
Alchemist
Top  #51 Print Post
Posted on 04/17/2008 6:12 PM
OK, I know - long time no action. Life got away from me.

Materials: I know you were waiting on me. I have to do some area calcs still, and will, but for the moment, start looking for some mild steel or aluminum. I don't care which. Food safe and "soft" is the key. Gauge - I check out a whole bunch and with as soft as mild or Al is, you have a very open window. Anything from 20-26 should work. 22-24 would be a tighter range if you want it. See what you find price vs amount wise.

Let me know what you find. Are you going to get it local or metalsexpress? I will get some amounts for you.
 
David
Top  #52 Print Post
Posted on 04/18/2008 12:19 AM
Welcome back, sir.
--
I will probably order the metal online.
I'll start pricing this weekend.
 
Alchemist
Top  #53 Print Post
Posted on 04/22/2008 5:46 PM
OK, I am not going to list out the piece by piece addition, but I wanted to get you some parameters to buy materials for. In general, it is the interior walls, bottom and chaff tray. Leaving your Stainless for the outside.

That said, look for aluminum or mild steel. Food safe basically. No galvanized. Technically we could use it in some of the bottom and interior, but I am trying to keep it simple. Look for 22-26 gauge. Kind of a wide range, but we can work with what you find. If you find 24, that is probably a safe better.

We want about (and I stress about) 24 square feet. Minimum 2 feet wide. You can go from there. 4 2' x 3' would work. 2 4' x 3' would work. One 8' x 3' would be ok. We will cut it up. Mostly keep it in 1' increments and we will be fine. I have padded the number there so we should have extra.

Questions? With that in hand, plus a little more angle aluminum we can start the cooler, as far as metal goes.
 
David
Top  #54 Print Post
Posted on 04/23/2008 9:02 AM
Roger that. I'll get on it right away.
 
Alchemist
Top  #55 Print Post
Posted on 05/13/2008 4:06 PM
Ok David, and folks. Getting very close to the first steps. With that in mind, I want to lay out what my plan is in verbal terms with a few approximate number. Basically lecture time. The real "how I do it" and why I say building this pup isn't going to be hard. It just takes time and thought, but no rocket science. Of course, more detailed info will follow. So, this is what has been going on in my head.

We have a roaster. The drum is about 8" in diameter. Lessons learned make me want a 2" clearance around drum. Then I want 2" insulation. 8+2*2+2*2 = 16" wide. I want the cooling try the same for aesthetic purposes. We are going to make the front curve around matching the curve of the cooling try and the back will square up to the roaster. That gives up base dimensions left to right and front to back, i.e. 16". Top to bottom. The tray is 3-4" (to lazy to look it up right now). The motor in question is 4" back to tip. 7-8" there. I again want some breathing room, so 10" high.

Construction: We are going to have an aluminum angle support and cover it with sheet metal. What we get here is a strong, light frame, reinforced by the rigidity of the sheet metal. The recurring theme in forming this roaster will be using some wooden jigs to attach parts to as a guide and for leverage. I wanted to stay away from a break for simplicity sake and approachability. Briefly, we will make a wooden form out of 2x4 and plywood in the shape of the part in question, minus appropriate material dimensions (16" - 1/8" - 1/8" = 15.75" for instance assuming 1/8" angle aluminum. In my mind's eye we will assemble the rough shape in 2x4's, mount the plywood, layout the exact shape and cut it all at once, no muss, no fuss.

The angle aluminum will be notched (see photos somewhere else), mounting and attachment holes pre-drilled (since it will weaken post notching but pre-assembly) and it will be mounted on one end to the jib. With leverage being our friend, and aluminum being soft, we will bend the frame around. Then we repeat with the sheet metal. Remove it from the jib and assemble.

A few notes on this part. I want a support under the cooling try "just in case" and we will need something to mount the stirring motor on. More angle aluminum notched, cut and attached, probably with a small sheet metal piece for support again. The frame I think I want to rivet together and I want self tapping sheet metal screws for the sheet metal attachment. We can decide if we want flush or raise screws for aesthetic purposes (your thoughts?).

The blower we will keep simple. Cut a hole, shove it through, and hold in place with something simple like pipe support. The final thing I want is to tape with aluminum tape all the interior seams for air tightness, just so the air goes right where we want it and no where else.

Ok, that is the basic road map for the cooler and the rough one for the whole roaster. What do you think? How far could you go just from those thoughts in place? Part of this section is to work out how we are going to really communicate construction procedures. What would be easy in person is fussy on line.

Your thoughts please.
 
David
Top  #56 Print Post
Posted on 05/15/2008 5:18 PM
The metal that I ordered has arrived. s:2
I will check it out for workability this weekend.

I understand what you have said above and can picture the roaster in my mind.
I'll be ready to start cutting and bending as soon as you are able to put up the drawings of the specific jigs and templates.
 
Alchemist
Top  #57 Print Post
Posted on 05/19/2008 1:17 PM
So, how is the workability. Did you/me/we guess correctly? The other thing I remembered (again) about specifying the materials was brought home when you mentioned how heavy the metal was, package wise, all in one place. That was one of my complaints about my Zen I - it was too heavy, although no one piece was that heavy. THAT was one of the reasons I was pushing so hard about 24-26 gauge metal and had some reservations about the free stainless you got - purely the weight of the final roaster.

But, at this moment, we have what we have, and we'll see how it works.

I am very glad you can picture the roaster in your mind. That is a great first step because if you can't see it, it is really hard to build it.
 
David
Top  #58 Print Post
Posted on 05/24/2008 2:09 PM
I opened up the package of metal. It does seem quite workable with hand tools. Grin

I see what you mean about weight, however. The next time we do this, I'll vote for lighter even if it means hunting around some more. c:1
 
David
Top  #59 Print Post
Posted on 06/22/2008 7:09 PM
From Alchemist's sketch I marked off the cuts on a 72" piece of 1/8th inch angle aluminum.

Actually, I decided to do two pieces in tandem, so I screwed them down to a spare piece of 2x4.
David attached the following image:
comp01z02z[978].jpg
 
David
Top  #60 Print Post
Posted on 06/22/2008 7:10 PM
After the cuts.
David attached the following image:
03z[979].jpg
 
David
Top  #61 Print Post
Posted on 06/22/2008 7:11 PM
There was 16" left over on each long piece.
So, I cut them in half, giving me the four 8" vertical pieces for the frame.
David attached the following image:
04z[980].jpg
 
David
Top  #62 Print Post
Posted on 06/22/2008 7:12 PM
I drilled some more holes and attached the two pieces to the board at the 8-inch mark, securing it to the board at the point of the first bend..
David attached the following image:
05z[981].jpg
 
David
Top  #63 Print Post
Posted on 06/22/2008 7:13 PM
This allowed me to gently bend the two pieces upwards...
David attached the following image:
06z[982].jpg
 
David
Top  #64 Print Post
Posted on 06/22/2008 7:15 PM
and around
David attached the following image:
07z[983].jpg
 
David
Top  #65 Print Post
Posted on 06/22/2008 7:16 PM
into a semi-circle.
David attached the following image:
08z[984].jpg
 
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