:woot:
welcome me to the club guys...
She came home to DADDY today!!!
My first phase change, too.
C
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:woot:
welcome me to the club guys...
She came home to DADDY today!!!
My first phase change, too.
C
have fun with your baby charly;)
what kind of temps you looking at charlie?
He told me non of them would put out. :slap: self :mad: . Stress full day.Quote:
Originally Posted by Revv23
I would be interested in the temperatures too ;)
Regards
John.
charlie we want some nice pics (this thread) once ya got it going.
Autocascade for you first phase change unit, ya a bit spoilt, now punish that WR :toast:
Hi Chilly 1,
It looks like you have a Polycold P-75 or P-100. That thing should do -120c.
The mix is most likely R-123, R-22, R-23, R-14 and Argon. If you are still playing with this let me know and I will come up with a gas charge for it. If you leave out the argon it won't get as cold but should handle more load.
I have P-75 that I use for cryo tempering.
I have a system that I get -170c out of.
-170 wow
what kind of load it holds?
:welcome: to XS :D
That you just have to post some pictures of, Im already drawling :slobber:Quote:
Originally Posted by cryo-tek
Holy thread revival batman!!!
Welcome to the forums cryo-tek, yes, post piccies of your auto-c please!
(Just a quick FYI that auto-c belonged to charlie, and if I'm not mistaken it now belongs to s7e9h3n.)
condensing argon with R14?Quote:
Originally Posted by cryo-tek
http://www.airliquide.com/en/busines...r_Pressure.GIF
the critical point of argon is -122, sounds like very dangerous bussiness to me.
I'm the current owner of the unit ;) It's been retuned an regassed by Chilly1 to bottom out @ around -87C on the evap and is able to hold temps @ ~-70C @ ~180-200W. If you're really serious about knowing the charge to get this unit to do -120C WITHOUT it taking 1.5 hours to get to that temp :p: - I currently have to wait ~20min for the unit to drop to a decent operating temperature - please drop me a PM so I can discuss this with Chilly. He's a busy guy these days and probably will miss this post :rolleyes: Also, would the modified cooling head play a part in the temps acheived by the unit? Look forward to hearing from you :toast:Quote:
Originally Posted by cryo-tek
sweet reallyt nice
Hi Unknown_road,Quote:
Originally Posted by Unknown_road
You're correct, the critical point of argon is -122c at about 47 bar. Check out the critical point of R-14.
My discharge pressures are around the 15 bar mark. So I need -150c to condense argon at 100% argon. The argon is only about 15% of the mix so now I need -173c.
What does the argon do? Two thoughts. One is that it changes the partial pressure of the R-14 allowing the R-14 to evaporate colder that the suction pressure normally allows. Thought two is that it acts like glycol in water and changes the evaporating point of the R-14. What do I know for sure; adding argon to an auto cascade will drive up the discharge pressure and temp. and It will lower the evaporator temp. I can have a -150c evaporator temp with a 2 bar evaporator pressure. What does your R-14 PT chart say? I hope I have these pressures right, I had to convert to bar on the fly.
What are your thoughts on this? Until I found this site I was in the cold with no one to talk to.
this mix is ok just with R-14 or is ok with other gas ?
Could you give some more info about the autocascade we are talking about here. How many stages is it? Do you know the temperature of the "last" heat exchanger?
http://www.airliquide.com/en/busines...r_Pressure.GIF
Hehehehe....Turns out that Cryo-Tek lives relatively close to me. I'm going to try to have him take a look at my auto-cascade and see what we can do with it. Maybe it's time for my auto to go sub -100C :D
welcome cryo-tek !!!
:toast: :toast: :toast:
Hay unknown road, Where do you find the pressure temperature curves that you post? They would be very helpful in understanding the Autocascade.Quote:
Originally Posted by Unknown_road
Zeotropes are normally defined at 0psi G and an average ambient temp of maybe between 25 and 35C, it could be that r14 and argon form a zeotrope at sub zero C, as autocascades are so specialised you would not find many references to this and hence not see anywhere that r14 and argon was a zeotropic mix.Quote:
Originally Posted by cryo-tek
Just speculation basd on the evidence, on my part, so dont hold me to that:D
Regards
John.
I thought about that John, but I think it's a little weird a very inert gas like argon would form such a blend (even zeotropic). But it could be possible, maybe it acts like a impurity such like ions in water lowering the boiling point of water.
personnaly I think it works a little different, little thought experiment:
when you have a perfectly insulated and closed bucket of water, you make 2 holes in it. in 1 hole you put a hose from witch dry nitrogen flows, the other hole is the exhaust. because the nitrogen is very dry, the water has the affinity to evaporate into the nitrogen faster as it normally would (when you leave a glass of water standing for a few days it will be empty although the water in it never reached boiling point) . When you compress the nitrogen after it comes out of the bucket the absorbed water will condens and form a liquid again.
Because the water in the bucket evaporates the liquid water cools down. phase-change without boiling ;)
Because the load temp of the polycold autocascade is the same as you would expect it from pure r14 I think this is what is happing in the system. @ no load, when the evap temp reaches -130 or something, the r14 stops boiling but not evaporating. argon has the "absorbing" effect twice that of nitrogen. So the argon works something like a spong for evaporating and thus allowing it to cool down futher.