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gordob
11-03-2011, 01:40 AM
Hi all,

A Client of mine has asked if it is possible to have a vessel fabricated to hold upto 250 Litres of Water in a Cube shape for freezing. He wants this vessel to be easily disassembled as it is going to be used as a sculpture piece soon. I have access to coolrooms as needed to try out designs.

My current thoughts are using sheetmetal to act as the walls of the tank as two pieces then use a silicon type agent to seal the two open joints. (i am planning to use some angle iron with threaded rod to provide the bracing for the walls and hold the weakened edges together)

I know this thread is VERY open to speculation and questions, but that is what im after. If anyone has questions, comments, ideas (or whatever else) to ask / say, Please do as i am still in the stage of thinking out the design)

Thanks,
Gordob

914Wilhelm
11-03-2011, 02:06 AM
How are you going to compensate for the volume increase with phase change? About 9% if I recall. Enough force to tear up your mold.

gordob
11-03-2011, 02:39 AM
Im thinking that if i use one or two Aquarium pumps to keep the water moving constantly as it reaches freezing point that i should hopefully be able to limit the expansion upwards. As far as i am aware, this should also remove any dissolved air from the water...

i would expect that the angle iron should contain most of the pressures involved, But i could be wrong

Boostinjdm
11-03-2011, 02:47 AM
Does it all have to be froze at once? I would think that freezing a layer then adding more water and repeating would limit the expansion to only going up. I wouldn't be too sure about angle Iron containing it since I've seen quite a few fence posts blown out from freezing.

914Wilhelm
11-03-2011, 03:11 AM
The force of expansion will be more than most mere men can contain here on earth without containers of extraordinary construction. If you start with boiling distilled water, the ice will be clear. Too much turbulence at the water air interface using pumps will likely dissolve more air into the water making it cloudy.

DickDastardly40
11-03-2011, 04:10 AM
Cloudy ice is caused by freezing water too quickly, clear ice cubes from a machine are formed by spraying water onto either a 'post' with refrigerant flowing through it so that it builds up gradually from the inside out or into a mould so it builds up from the outside in. Hot refrigerant is passed through the 'post' or mould after a predetermined time to get the cubes to harvest and fall off into the collection tray. You can tell which method they were made by by if they are solid and have a small dimple in (mould) or if they are like a shot glass (post).

A ship I used to be on had brine tanks for making ice by secondary cooling, ie the refrigerant cooled the brine which cooled the water in the mould suspended in the brine tank. The moulds were aluminium about 3 feet long by 6 inchs wide.

I would experiment with a tank made out of screwed plywood with wooden battens for strength lined with a plastic sheet. As long as the ice can expand upwards into you might be OK. Once your ice is formed you could unscrew the mould and remove your berg which would be easier than turning it out.

gordob
11-03-2011, 04:22 AM
Boostin, i wasnt thinking small scale angle iron, more like 50x50x5 mm stuff. I have watched the professional ice suppliers freeze their cubes on youtube (Link: http://www.youtube.com/watch?v=itvuudjb9hk) and most of the expansion occurs vertically (but that could be the freezer also)

Ideally i would like to freeze it all at once to maximise structual integrity of the block. I believe that the point where the sections meet could prove to be a weak point.

thanks again for your input

Doc Nickel
11-03-2011, 04:32 AM
It needs to be four piece (technically five including the floor) and it'll have to have tapered sides (wider at the top.)

Make the flanges at the corners, and make 'em heavy enough to take a goodly number of heavy bolts (3/8" or bigger.) The best one I saw had square broached holes on one flange, and just wing nuts to hold it together. They don't need heavy torque, they just have to be strong enough and numerous enough to hold it together.

That same one had machined grooves for a round rubber seal (basically a cut-open O-ring) but still needed a dab of some kind of nonhardening sealer at the corners. It was meant for essentially "production" of heavy ice blocks, if you're only doing one at a time or a few at a time, a silicone or possibly even a thick axle grease might work. I even saw one that used tape.

The water needs to be either boiled or vacuum degassed for clarity. I've seen homebrew versions of both, the vacuum tends to be quicker and less energy-intensive, but you need a high volume pump for a significant amount of water.

A square-sided mold will blow out, or at least bulge, even if the walls are 1" plate steel. You must taper the sides, and have them smooth enough for the ice to slip a little. (Doesn't have to be mirror polished, just don't have exposed bolt heads or internal reinforcing ribs, etc.)

Doc.

gordob
11-03-2011, 05:35 AM
Doc,
Part of my design requires the use of a square sided design. im sure i should be able to live with a degree of bowing in the sides of the block considering its going to be sculpted anyway

madmec
11-03-2011, 07:11 AM
Here in Germany we have a kind of "thermal accumulator" heat system wich uses a large water filled Tank. During the winter month some kind of Refrigerator freezes the water, providing heating for the house.

The trick to keep the Tank from bursting during freezing ist that they start it in the middle of the bottom of this tank. This way the Ice can expand upwards and sideways until its completely frozen.

I would suggest insulating your "ice cube box" on all sides except bottom to generate this effect.

Thomas

SGW
11-03-2011, 07:32 AM
If I did the math correctly, a cube to hold 250 liters works out to be a box just under 2.07 feet (about 63cm) on a side.

Duffy
11-03-2011, 09:19 AM
You dont*say where you are. There is a company in Clinton, Ontario, Canada that specializes in producing "sculpting ice" blocks.They supply restaurants and organizations with LARGE quantities of clear ice blocks all over eastern North America. I suspect that they can produce and deliver they required block for less than the cost of a tank.
Sorry, dont know the company name, I just know that they supply all the ice for the annual Ottawa Winter Carnival ice sculpture contest, which amounts to MANY truckloads.

DFMiller
11-03-2011, 09:57 AM
Iceculture.com
Dave

lynnl
11-03-2011, 10:22 AM
I have NOT done the math, but I'll trust SGW's work above.
Given that it's only about 2ft cubed, I'd just get a plastic bin and use that. It will permit the bulging as the freezes.

I routinely freeze water in 1 gal milk plastic jugs, as well as 1/2 gal cardboard cartons, leaving about 1 inch of air space at the top. They bulge slightly, but never rupture.
Granted, that's considerably less than the 250 liters, but with an open top plastic container I don't think there'd be any problem.

SGW
11-03-2011, 10:36 AM
I have NOT done the math, but I'll trust SGW's work above.


You are entirely too trusting! :D

What I did: 250 liters is 250,000 cubic centimeters.
250,000cc is 8.83 cubic feet
The cube root of 8.83 is 2.067, so the cube is just under 2.07 feet on a side.
And 2.07 feet is about 63cm

As a check, the cube root of 250,000 is almost exactly 63.

strokersix
11-03-2011, 10:57 AM
If you somehow built a container strong enough to hold the pressure the water will freeze at a lower temperature, then your container will burst.

Kind of like the radiator pressure cap on your automobile raises the boiling point.

gordob
11-04-2011, 02:26 AM
Where are my manners?? Im located in Sydney, Australia.

My thoughts on using a submerged pump to keep the water moving (whilst ensuring the pump cannot suck air) should hopefully allow me to control the pressures associated with the big freeze.

i also forgot to mention that i can take the cool room down to a toasty -24 degrees Celcius too.

The measurements of the vessel having 63cm Wide Side walls is spot on also

darryl
11-04-2011, 03:37 AM
Looking at this from a different perspective, don't even try to contain the ice as it's forming. Just arrange the walls to come together and make a sealed box capable of containing water. As the ice forms, the walls get pushed apart and you could take them away. I'm thinking that since the water is probably going to freeze from the outside in, that once it began to freeze it would become its own container. The walls would only need enough strength to contain the volume of water, and enough weight to maintain the bottom seal. You would connect the corners with removable spring clamps having only enough overall clamping force to keep the seals in contact when the 'tank' is full of water.

If each side had about a 2 inch wide flange bent out at 45 degrees, the four walls could come together with the flanges all touching. A seal would be between each pair of mating flanges. The bottom of each wall would have a flange also, but bent out at 90 degrees, and that creates a place for the bottom seal. If that seal was attached to the wall, it would be displaced the same as the wall when the water freezes. You should be able to get a reasonable degree of durability from it, and repeatability in sealing to the bottom 'plate'.

Just an idea.

Kiwi
11-04-2011, 05:34 AM
What stops the submersible from freezing solid and burning out ?

sandiapaul
11-04-2011, 05:36 AM
I wonder if this is the same guy...I offered some advice on this about 2 years ago...then never heard anything back. Or maybe its the "hot" new thing, ICE!

RussZHC
11-04-2011, 02:22 PM
Me thinks this is going to take some experimenting w your particular freezer as well as the other conditions affecting the overall project.

We freeze relatively small blocks 3x8x12 (inches all measurements) just inside a small deep freeze, using plastic margarine tubs as the "mold"(expansion does bulge the side which are tapered)...
the time to freeze is all over the map (access to the freezer and other things it contains is pretty random) but also seems to be influences by where in the freezer the forming block is placed (sort of the reverse of hot spots in many ovens)...
this time means we sometimes end up with blocks that are not frozen through and through, the ice is sometimes very clear and other times a bit "cloudy" or bubble filled, for whatever reason... some blocks also seem more prone to fracturing (but even then some sort of split into large chunks whereas others just shatter)

MrSleepy
11-04-2011, 06:15 PM
If you somehow built a container strong enough to hold the pressure the water will freeze at a lower temperature, then your container will burst.


you can create ice by compressing water at 15000atmospheres pressure...it forms at room temperature...the volume reduces...and it will not melt unless taken above 100c.


Rob