The beginnings of a beautiful thing... -150C
http://www.blairwing.com/images/3stage/1.jpg
http://www.blairwing.com/images/3stage/2.jpg
http://www.blairwing.com/images/3stage/3.jpg
http://www.blairwing.com/images/3stage/4.jpg
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The beginnings of a beautiful thing... -150C
http://www.blairwing.com/images/3stage/1.jpg
http://www.blairwing.com/images/3stage/2.jpg
http://www.blairwing.com/images/3stage/3.jpg
http://www.blairwing.com/images/3stage/4.jpg
looks real nice good luck
I never get tired of looking at system pics. Its amazing what people can build in their spare time.
What size capline you use from the valve to the evap? Looks sooouu nice:) A Pro is always a Pro no mater what, and it raly is visible in this sytem.
The tubing supplying the refrigerant to the evap is a 0.060 ID tube the metering device is the PEV which in this case will regulate the input pressure into the tube...
looks realy nice! btw what kind of brazeing rods do you use?
On the block I use 56% silver solder and on teh copper to copper I use 15% silver brazing alloy. With teh 56% you must use a floride paste flux with simmilar melt point to the solder. For teh 15% no flux is nessassary.Quote:
Originally Posted by JSU
This looks very very good!
It is a bad idea to take copper/phosphor brazing rods? Because I can get 5 c/p rods for the same price as for one silver rod
Looks Neat. Wish i had one or 2 of those laying around.
not bad, chilly :D
will it be r507, r1150, and then methane??
do you remember care50 post a few weeks back
r290 50% ethane for -50c at 1 atompshere and lower pressure than r410a
i recond if you got some ethane and played around a little could get a really cold first stage going
Phosphorous copper is good for copper to copper joints and dont need flux. Easy to use and cheap. With propper Silver rods you can braze almoste anything (exept aluminum) and you can get the rods that are covered with flux so no need for manual fluxing. Propper silversolder costs helluva lot but you realy don't need it unless you solder stainles to copper etc.
First stage R507, Second R1150 + 2 oz R12, Third R50 +25% R740 + 2 oz Ethlyene + 2 oz R12, This will be the first Range of refrigerant I will try. I am going with R12 instead of propane because of its misicibility with the oil.Quote:
Originally Posted by SlackeR
1. How do u measure 2 oz?
2. What the heck is R740 and why are u using it?
3. How are you going to add 25%?
2. R740 is argon, it has a boiling point of -182C.
Argon= R740 instrument grade, R50= Methane CP grade, R 290= Propane instrument grade.. Instrument grade is 99.997% pure , CP grade is 99.95% pure, My propane does not small (No mercaptian)
Are those plate HX's expensive?
And is the schematic for that 3 stage in your cascade drawings thread?
Cant wait to get some numbers on that beauty when you fire her up :)
Regards
John.
This is my three stage design. There are a few things in the block not shown... But basically thats it. Plate HX's of this size (originally for a 1/2 ton chiller) are 195 US plus shipping. This is my first cascade with plate HX's..
Update.The Argon needs a colder condensing temp (-130) to operate properly at load. The methane needs -100C to condense, On first run we found we had a dead first stage compressor, changed and restarted, third stage compressor started and hammered then tripped the breaker, Bent rod or broken poiston "Hammered it to 600 PSI" Danfoss compressors destroy them selves at 600+ psi. Changed this compressor charged third with ethlyene temps down to -112C on block... First at top of HX (outlet) -20C second HX (outlet) -70C Minimum for operation with methane is -95C , Working on it, I will post the answers asap... Probably remove the HX's and redesign the interstsage... Need more capacity. Maybe move up to a 2 hp for first and a 1hp for second. Tried a few blends only more of the same Temps stay the same but pressure rises with blend,, no Gains, Blew up a capacitor, dont stand over a start cap on a system.. Covered in Oil from the cap,,, More to follow...
ouch well atleast you are making some progress and gathering info.
you guys sure live on the razors edge :D
***OT***
here after awhile when money if gathered and wife won't notice ;) I will be contacting you via PMs on a nice -60+ single stage setup.
Anything over 2 stages requires some seriouse thought. Designing a system so that interstage temperatures are just enough to condense the next stage is foolish. You always need to alow plenty of room for error. When designing a 3+ stage system I will always be sure my 1st stage is nearly twice the size of my second. If designing a 4 stage, use the same logic... like Biggest, bigger, big, 4th stage. lol get me? Also an excellent way to minimize interstage loads is to pipe a completely seperate condenser with a fan, as a desuperheater. Use say, the first 5 or 6 loops to desuperheat the 1 stage. then the next 4 or 5 for the second desuperheater and so on. This will allow the bulk of the heat from each stage to be blown off prior to entering the interstage. This minimizes the desuperheaters physical space, while maximizing surface area.
C.C.
keep going chilly!!
Captain Long time no see, I am close to being able to condense methane the bottom of the HX (brazed plate) was -95C. The Metering device is an expermential valve from sporlan, The first compressor I had was 2X times the second but it was a DOA. I used a 1 hp R22 in its place and My condenser is a little small, I am instaling a larger one. Also I need to install a larger second stage air coil before the oil seperator, The discharge temp of the second stage was 215F which is about the limit of the compressor I had there, THe Third stage compressor has the same displacment as the second but with methane the BTU that it will dissipate is nearly half that of the previous stage. So With a few tweaks it should work...With methane.
Are you thinking a fourth stage may be required to condense the Argon? I dont know if you can get plate HX's that have 3 routes, can take three gases in seperate paths. Hope that makes sense. You could maybe run the discharge from the fourth stage and route it through all the HX's then.
That way the first two HX's would desuperheat the argon at it could then condense in the third? Probably damn expensive though, even if such a thing exists :mad:
Regards
John.
I am a little dissapointed at the preformance of the Plates but I can work with them. I did a few calculations on the enthalpy and critical temperatures of argon and we will need -140C to condense it at anywhere near resonable pressures.Quote:
Originally Posted by pythagoras
It blew up like a party popper, a white silly string like substance stuck to everything in its path.
CC, good to see you around.
I agree, we will need to hit ~10c beyond condensing temps of the next stage to be safe. With the expansion valves ability to maintain temps under load we dont have to get excessive here to maintain the capacity of the load. With a cap tube I can see where this would be a problem.
We need to hit -100c on the second stage @ ~ 20 psi to get the methane condensing.
A bypass valve may also help on restarts to equilize the pressure and prevent another blown compressor.
We needed a video of last night, two blown compressors (one doa, had start problems on first stage unloaded with R507), A blown cap.
Once running we had no problem getting the first two stages going in no time. They ran for hours and we swapped out the third stage compressor after failure with the first two stages running.
Though i dont know the specs of your plates, judgeing by their looks. I would say they might be a bit undersized for what you are trying to achieve... well with what compressors your ussing.
Lets see if i can make sense here?
plates offer a great deal of suface area. good
plates offer little (if any) restriction. good
Now lets take into acount the raw thermal conductivity of methane in its gas form. right.
Shes a thin little bugger of a gas. So what this means is that though a plate may be rated for 1/2 a ton. it aint gunna pull a half a ton. do you understand what im sayin?
you may need to make that 2nd to third interstage a bit larger bud. :( :(
Oh and you guys should call me next time all of ya hook up. maybe ill swing by and make some :banana::banana::banana::banana: cold with ya :D
Quote:
Originally Posted by pc ice
I dont want to see either of you vogue, strike a pose, bust a move, or even get down on it. thanx
sorry i couldnt help the cheap shot. i cant spell either lol
Actually the plates are five by twelve inches by 10 plates so the surface area is 60 x 10 x 2 -(40 for the two outside plate sides) or 1160 sq inches. almost 10 square feet. Considering the uppr half of the plate was uninsulated and there was no insulation on anything else. I needed to see where we could improve, refrigerant flow is a little differant in plates Unlike tubing both surfaces of the indivigual plate are used for heat sink area. As for the 1/2 ton rating that is at 3 degrees F at 38degF with 10 GPM of water and R22 gas. And as subcollers they are rated at 5 tons with a 25 degF TD. I suspect I blew the compressor a few weeks ago when I tested the pressure limit of the compressor. (Danfoss sc12mlx reaches its pumping ability at 10 psi into 600 psi and the compressor stops pumping and bypasses) DON'T TRY THIS ONE AT HOME PLEASE
The midstage needs more subcolling as the discharge temperature is high. I really need some R14 as we are at the nessassary condensing temperature for that.
i hope you understand my crapy drawing. its just a plain old condenser with three seperate runs for subcooling
So you are using the suction lines to shuffel the heat to the first stage with out using the second two compressors?
Is this what you mean? Like a tube in a tube in a tube in a tube in a tube in a tube. This is what I had in mind after the trial run...
http://www.blairwing.com/images/3stage/4.jpg
ugh your killin me, It isn't anything super inovative. Its just a cool easy way to pipe a desuperheater.
ill explain again.
serpentine condenser.
from the inlet to the outlet, lets say it goes back and fourth 10 times.
in a serpentine fashion.
now cut it so that we make 3 seperate condensers.
in goes in through the inlet.
goes back and fourth in a serpentine fashion.
but then we cut it.
so it only goes back and fourth 3 times
then it goes out to its respective condenser.
lets call it a 3 in 1 pre condenser
someone help me
Sorry cap. Still not making any sense. Sounds to me like it is only a desuperheater. Got some quility Pics? Or are you talking about an air cooled condenser? Where you take the loops of the second and third through the condenser itself? I am installing a small air coil after each sucessive stage also the heat load calls for it also.
this way, cc?
i dont beleive hes having trouble understand the concept but more the ending result.
So why add an air cooled condense rto teh first stage when One is already there?
Add an air coil to teh discharge to the second and third, already have these. I will need to expant the condenser or pre condenser for the second stage substiantially. The subcooler will be made of 6 concentric pipes of 14 inches to 16 inches with y fittings...
awsome chilly1, but where did u get argon?
liquid air or boc gases
NGC gasses affiliate of Aire Liquide
First of, I'm in no way claiming to know better than you guys. I have never even built a phase-change system myself yet.....
But I'm really intrigued by reaching really low temps, and I have read most of the amazing book: Cryogenic Engineering by Thomas M Flynn. It has taught me a lot on the physics involved in reaching these temperatures.
One thing that puzzles me about all the approaches you have chosen is that you don't seem particularly concerned about reusing the cold you have worked so hard to achieve. What I mean is that what you do with the gas from the third stage in you setup chilly1 is to use a fraction of the remaining cooling potential in it to subcool the incoming fluid/gas mix to the evap. But after that it is sent directly to the compressor! What a waist! If that gas is leaving the evap at -100C (if your goal of -150C evap temp that is even a bit high?) it still have quite a lot of cooling capacity (and that at a really low temperature even!).
What is important here is at what temps your heat loads is at. You all know that lifting 1 W at -150C takes WAY much more effort and energy than lifting 1 W at +20C. This implies that it is also les energy demanding to cool a gas at reasonably high temps (in the 0C range) compared to cool it to really low temps, and even possible to do it "for free" if the temp is above room temp.
This can be translated in to the following:
If you want to reach low temps you will gain efficiency by cooling the gas in the third stage of your cascade in several steps. What you want is to use an as efficient cooling as possible. First of you should implement an air (or rather water) cooled HX to get rid of excess heat above room temp (water temp) introduced by the comp. This will releave the second (and first....) stage of having to lift the heat introduced by the third stage comp. Then you would possibly want the next cooling stage to be done by an as efficient system as possible meaning the first stage. This stage is possible to make really efficient compared to the cascade the first and second stage is made up of. This way you will not have to use the not so efficient cascade to cool the gas from around room temp to a reasonably low temp (lets say about the evap temp of stage one….), thus using les energy to cool the gas, thus being able to lift more heat at the low temp.
Then there is the possible cooling potential of the gas leaving the CPU evap. after it leaves the subcooler. Remember that this is low temp, and therefore precious heat lifting capability that should be put to use. Remember that each heat lifting Watt here has gone through 3 stages of cascade and used a lot of energy to get at that low temp. This heat lift potential could be used to cool the gas in stage three before it enters stage 2/3 HX. Each W lifted from the gas before it enters the HX gives one more W heat lifting capacity or less energy used to cool stage 3.
To sum it all up, by using cooling processes that work in the appropriate temp region and to split it where the temperature range is to big is the key! The energy needed can fast reach 100 W used to lift each W at -150C! So you want an as efficient system as possible if you don’t want a HUGE electric bill…… and a hot computer room :)
It also seems to me that you should be careful to make sure the HX’ have good recuperative capabilities…. hm… not sure if that is the correct word. What I mean is that it is important that they are counter flow, and that the temp of the cooled gas leaving is close to the temp of the cooling gas entering. Plate HX’ with a wide footprint (meaning they are fairly wide compared to the length) isn’t as good in that respect, and tend to spread the heat to well if you understand what I mean.
In reaching these temps the HX efficiency is also really important, but the most important factor is in fact what is happening at the top of the system! Flynn had one comment this. Most designers seem to forget that all the work is done on the top (in and around the compressors where the temperature is high) and 99.999% of all refrigeration research has historically been done on the cold end. I think we should take this in to account and start by thinking again at what ways we have of improving things in the system.
Precooling is a major efficiency increasing factor. An example in the book describes the way precooling with LN2 to make LH2 liquefaction increases the capacity significantly. And the amount of used LN2 isn’t even more than about the same as the amount of LH2. And since LN2 is a LOT les energy demanding the net result is a huge saving on the energy used.
To get a better idea of what I’m talking about take a look at the Linde Liquefaction apparatus and how it operates. The key here is the heat exchanger that preserves the cold at witch the cooling takes place and makes the apparatus able to cool it to so low temperatures. If the HX’ efficiency is to low it will limit the lowest temperature it is able to reach.
The problem is that if the HX isn’t able to transfer enough energy needed to preserve the cold the energy the temperature reachable by the process is limited by this. And at the temperatures here the efficiency of the HX’ need to be better than 90-95%! So that is another place I would start looking. I’m sure you guys know how to measure and calculate it.
But to me the temperatures we are talking about here seem to call for other methods of cooling. And you chilly1 seems to have most parts of a G-M refrigerator capable of really low cryogenic temps. But the costs to operate it alone (both the ultra pure He and the absorbers in the filters) seems rather high to me. And then there is the efficiency problem. You have seen the compressors needed for this system, and they are as you have seen LARGE (wasn’t it 5 Hp or something???)! That is because the efficiency of this process is magnitudes (as in possibly 1/10 ) as efficient as the more efficient methods (phase-change, stirling, turbo-bryton and others). The reason for it being used in the vacuum chambers as you probably already know is the durability and the ease at witch cascading is accomplished.
My (over a very long time though) plan is to try to make a stirling cooler. I have a CNC-mill (oh well, soon the z-axis is converted too) in my basement, and I’m going to use it to make both stirling coolers and motors. My plan is to make a not so high-tech version of the wisper-tech stirling motors.
Hmmmmm…. sorry for making this such a long rant, but it’s kind of hard to explain these things in short terms in my own language, and even harder in a language not my mother-language.
And again, I’m NOT saying I know more than you guys. On the contrary…. I’m just trying to understand how real life implementations are done of the engineerisch (my second mother-language too :) ) language discusions in that book. BTW I really recommend this book to those of you really interested in reaching low temps (and understand engineerisch…..)! It has whatever you want to know of cryogenic properties of both fluids (gasses at normal temperatures) and solids. A lot to be learned on heat conduction in there! And there is even a whole chapter on insulating that is really informative and useful for our purpose! It’s expensive though, so a library visit is probably the best way to have a look, as I did.
akb1212 going back to lurking mode..... :cool:
Here is a drawing of my propased changes to the three stage as a result of findings from the first run. And yes I am trying to simplify the three cascade as well as make it more effecient. At the same time I wish to stay inside the relm of what I can build in my garage or purchase off the shelf and also power with house current. I do have economizerizers on this cascade but there is way more heat being generated by the second stage than I antipiciated and I have a solution for that also. There is a limit to how much superheat you can add to the gas entering a compressor and still be able to compress it. SO itf you heat the suction line too much you will end up too high a suction pressure and you will lose effeciency. The Subcooling HX in the drawing should shuffel the heat from stage to stage bypassing the compressors. This may help... http://www.blairwing.com/images/3stage/3stage.jpg
We got the compressors to cool down considerably. The methand was condensing in teh third stage but it does not have the capacity to work in this system. R14 will as teh mid stage condensing temp (R503) is -85C first stage was-30C and the final temp with Ethlyene was -114C, Looking for R14 for this rig now. sent it over to fuggers shop for bench testing. Its been a learning experience, We need to find some better gasses for the third stage or add a fourth either an autocascade forth and fifth or other method to condense Argon or nitrogen.
Well here are the final pictures I took here...
http://www.blairwing.com/images/3stage/5.jpg
http://www.blairwing.com/images/3stage/6.jpg
http://www.blairwing.com/images/3stage/7.jpg
http://www.blairwing.com/images/3stage/8.jpg
http://www.blairwing.com/images/3stage/9.jpg
holly sheat....u r crazy...!
We ended the night with a blown circuit breaker and didnt have the camera ready to take pics to the temp meters. With proper insulation and finer tuning I expect to hit closer to -120c
I also have the capability to subcool the entire unit 20 to 30 degrees colder than Cilly1's garage.
The third stage compressor ran nice and cool, it had plenty of cooling getting back.
The R503 is pretty nice, it drops to temp very quickly and has huge capacity. I have never seen the R1150 drop so fast. Watching the meter -19,..-25,..-46,...-72,..-95,... After we pulled the methane with first and second stage running we shot in some R1150 and fired it up.
We did condense methane. We reached -60c or so before making the call to switch back to R1150.
Add another Aspera 3/4HP compressor to the dead list.
It refuses to start with bypass wide open, it even tripped the breaker without a load.
Going with tripple danfoss SC12MLX
man u guys are lunatics!
600 posts, wheee!
man i cant belevie what i see that is a work of art guys. :slobber: :slobber: :toast:
well done cant wait to see some more
you added fans on the oil cooler/desuperheater????
After the first run the temperature and test results pointed at different areas to remove heat from and not add it to the interstage hx's This made it possiable to condense methane, which BTY has little heat capacity looking for alternatives now.... R14?
think its a good idea in a regular cascade?
On the second stage a little coil usually does the trick but if the refrigerant is exiting the oilseperator above ambient it can only help/.
r503 has a molecular mass of 87.25 and works well, r14 also has a molecular mass of 88.
so do you think that they will act similar?
where as r50 was 16.04 and not a very good gas. does molecular weight relate to the capacity of the gas?
Yes molecular weight and its density when compressed. These relate to its enthalpy.
I was looking through one of my dads old chemisty books and it shows that r14 boils at -150~ @ 100mm , I believe tha is around 4hg. So that sounds like a good 3rd stage refrigerant. The reason I said -150c is b/c carbon monoxide is a liquid @ -150 and 20bar, so that sounds like a realy good candidate. It boils @ -190~ with 1 atmosphere.
Carbonmonixide has a triple point also. That is the reason Co2 is such a hard refrigerant to use also.
I didnt notice that, ill have to check. You could probobly mix it with some argon or r14 and have it work alright. It still seems like a awsome refrigerant if you can condesne it.
and carbon monoxide is extremelly dangerous, when you brathe it, it blocks hemoglobine in your blood cells and you die with blood transporting no oxygene or you get REALLY sick for a few days at least. I was poisoned a few times with it, belive me you dont want to feel it
it only takes a few days for your blood to replenight itself? I have one of those masks that block ALOT of harmfull chemichals. It might be able to block co. Btw berkut how did you get poisoned? Jet engine?
same as N2 one mouth full and dead.Quote:
Originally Posted by berkut
80% of the air is N2 ;)
NOS is a bigger problem :)
Nos is the one gas (drug)that has had none of reported deths other than people faling asleep form inhaling it and hitting their head in the process:)
speaking of which, has anyone used the stuff in a cascade yet?
also there are 2 differant kinds, the one used in cars and the one your dentist has.
Isn't it NoX you are talking about here???
I do belive that if it had some real application to refrigeration it would have a R numer as in R740......
NOx is an oxident and should never be used in conjunction with a fuel (oil) under pressure with a possiable sourse of ignition.
wait, the Nitrous they put in cars, is nitrous oxide right? so its... N2O3, or N02, or what?
i think nitrogen is +3, and oxygen is -2, so it would be N2O3 or something
someone listened in chemistry.
N allso has a negative value if i remember correctly. And even a -2
so it is NO i think :)
but that's not really important. It is to dangerous to use in refridgerant systems. There is oil inside and oil + oxygen = bomb :)
wasnt NOX, NOS (however they call it) N20 ? :P
too bad the guy across the road does drag racing has a street legal car on nos.
hes always got 2 bottles laying in his shed that i could use.
i have a feeling its n20 with a yellow sticker
NOx is a collection name for NO and NO2(nitric vapors). the brown smoke you get when you poor some nitric acid(HNO3) on copper is NO. it is very harmfull if you breath it in.
Sorry, my mistake
NOx is NO or NO2
NOS is N2O (laughing gas).
But none of them are usable as refrigerant. They are all reactive.
NOS is also liquifyed at 50 bar at room temp, and boils at -88.5C at 1 atm and freezes at -91.8C. Not good for a refrigerant is it?
But I have to say that it seems to me that going from one stage to a normal (two stage) cascade is a rather huge difference. But I would expect going for a three stage is an even larger step towards a complicated setup that is way more complicated in ALL ways.
BTW what is the difference in OC when going from -100C to -120C (it seems to me that it is hard to get loaded temps below that temp even when using 3 stages)? Is it such a huge difference? And think about all the work to get those few degrees...... And how about runtime??? How long can one expect to run such a rigg?? Is it so much longer than a LN2 setup after all? And is it cheaper in the long run?
All these are questions I'm asking after looking at you guys strugle.
My answer would be to start looking at stirling cryo-coolers.
? lost stuff
We lost pages???? Checking>
nope. the nos/nox discussion is just in two separate threads:) This and the compressor oil Thread.
Did it get split?
Yes it kinda did. My gues is that you ment to post in this thread but accidently posted in the other one:)I was wondering why the discussion changed from compressor oil to the dangers of nitrous...
Chilly1 when did you hit that INSANE temp???????
I think that is in Kelvin, and 300 is actually quite high
um actualy its in ferenheit. Its impossible to be kelvin b/c it is negative. Well I found the thread. But I think LN2 is cheating...... Still very nice setup over there.
Why is Ln2 cheating It is using a pump and a compressor to cool that much, plus with one more stage I will be able to liquify nitrogen...
And Yes that is -300F and that is -185C
not reusable, i thought that it was in a closed system :( .
btw if you are going to the lowest pobbible temp why dont you pull a nice vacuum on something then let some ln2 in? rolly be realy realy cold and frosty
I am using a vacume pump on the outlet of the block to siphon the nitrogen out of the dewer. (No styrofoam cups)
Just to clean things up.
NOS = Nitrous Oxide System
That's the also the most known manufacturer for such car systems, so everyone calls it NOS. :D
I think a warning is in place here!
If you are working with LN2 temps things are starting to become VERY much harder to insulate. And there are real DANGERS if it is not done properly! These dangers are possibly even more severe than the dangers of cascade systems! WAY more severe!
Ok, this danger is caused by the following:
When not insulating metal parts that are at LN2 temps there is serious chance of condensing Liquid Oxygen (the condensed fluid will normally have about 50% LOX since O2 have a higher condensation temp!) on the bare surfaces. This is a highly dangerous liquid if not handled correctly. Most of you probably know that when using Oxy/Acetylene torches the O2 path have to be absolutely clean from ANY grease or other hydrocarbons. The danger of explosion is very large. And think of LOX as even more dangerous in this respect! The concentration of O2 molecules is almost 1000 times that of atmospheric O2, and then 5 times the concentration of the 200 Bar O2 in the pressurized bottles. I have seen pictures of completely exploded labs not showing care here! Remember that LOX is a low viscosity liquid and will collect at the bottom of whatever contains it, and oils and so on are also lightly to do that. And remember how efficient it is as oxidizer for rocket fuel!
And about the insulation. Most of you use insulation with trapped air bubbles. Remember that this air will be condensed at these temperatures after a while. This will make a vacuum in the bubbles, and since the structure of most plastics at these temps is drastically changed things are starting to change. The insulating properties are decreasing and the phenomenon is spreading.
If you use the way of using completely dried air in the computer to prevent ice to form on the components you are actually making ideal conditions for making LOX inside your container with the dangers that involves. You would not want this to happen! One way to avoid it is to make sure it is boiled of on the CPU or whatever.
Vacuum is probably the best insulation, and I would recommend it as the first choice. Most of you guys have access to vacuum pumps anyway, right :)
One other possible solution is to use Argon as the insulating gas. This is heavier than air and can be trapped in the bottom of a case. And most important of all, it is not explosive, poisonous or whatever and at the same time relatively cheap and easily available.
So chilly1 and all you guys fiddling with LN2 you really should study it more before going ahead. There are real dangers here that are all but obvious if you are inexperienced in this! Remember, this is LITERALLY rocket science! How many of you are rocket scientists? :)
Hi akb1212,
Would you mind filling us in a little with your background, it seems to me as though its scientific or lab tech stuff. And welcome to the forums.
Regards
John.
Um it is realy hard to condense O2 with LN2 b/c the condensing temps is realy close. Another thing is that you will have condensed/frozen water before you get O2. So because of 1. Having a barier of ice between the o2 2. The fact that the temperatures are so close 3. The o2 will probobly evaporate before it collects. 4. The area around the container is mostly N2 due to the fast evaporation of LN2 (namely no O2), you prolly wont see any LOX.
EDIT: I have tried making LOX using LN2 and it didnt work. Thats when TRYING to make it.
Quote:
Originally Posted by JSU
But i guess they are discussing the use of N2 in a cascade not in a container as we have seen many times before. The lowside of a cascade running a extremely lowtemp refrigerant would need to be carefully insulated, that's what i think akb1212 meant :).
But you got a point, there will be a barrier of ice before the O2 will condense on the surface.
The coldest surface on this setup will be the head of the block. The insulation is a problem, I do have access to nitrogenized foam glass insulation if and when we decide to full 24/7 operation. The Ln2 is being moved from the dewer by an open supply loop to the block, The insulation on the 20 min run shrunk up considerably but never dropped below -5C, water was condensing on the outside of it (3/8") and this was standard neoprene closed cell. With the setup on a working computer with it insulated with 1 inch closed cell foam we should have no problem. We are looking for -178C to -184C internal on the processor so the coldest the setup will see will be -195C.Quote:
Originally Posted by akb1212
I have some metering devices (Ln2 specific) for controlling the flow rates and therefore the temperatures.
you do know he is a certified HVAC engineer....right?Quote:
Originally Posted by akb1212
Ooops my bad, I thought that was positive 300K
Thx for the questions, as for the dangers of Ln2 they are very real and this needs to be understood fully before handeling it in any form. Ln2 in a line as I am doing here has it's own set of dangers that need to be addressed, as with any liquified gas in a line aas long as the Ln2 is liquid and at temp there is no problem but almost instantly the line will burst if you close it off on both ends, So every line every valve or device has to have a means of relief, The burst on the copper lines I use are 2000 psi with 1200 psi working pressure max. My reliefs are 20psi leaving me a comfortable margin. If Ln2 contacts skin or soft tissue you will lose it. No second chances with this stuff. This is why I use a tank with a relief and a open pume instead of a compressor.
lol, yeah, they use ln to burn off warts...:P my brother had tons of them:P the doctor did it..not me hehe
nyways, awsome temps chilly1, are u gonna put that on a chip?..
It will be on a chip by next week.
:cool: what chip?Quote:
Originally Posted by chilly1
this is probably the most "evil" rig i have seen.
And i f00king l0ve it !
I dun?t even think it?ll matter what chip, lol, its still gonna run fast?okey, lol, a 500mhz Celeron would be lame?
oh yeah, chilly1 do u have pics of ur setup?
there are some in the start of this thread, but i dare you to look at it,Quote:
Originally Posted by HawainPanda
any moment soon, Aliens will pop out of it and thake a big bite out of Berkut's left legg :D
why thank you! wait till you see the frankenprommie I am working on.... Poor prommie died a premature death, home depot had a sale on food processors, belt sanders and airconditioners, from the butchered remains of these and the contentts of a couple welding shops and supply houses the resurected remains of "Prommie" shall be brought to life!Quote:
Originally Posted by Zejtan