Auto-c gas ratio that gets to -140

[Quasi]

[0037] The refrigerant mixture should consist of R142b (22 oz.), R134a (20 oz.), R508b or R508a (18.2 to 19.7 oz.), R14 (16.7 to 17.5 oz.) and R740 (14.6 to 17.1 oz.) to achieve a freezer of -140.degree. C. to -154.degree. C.


Found this on a patent site and didn't pics yet of the physical setup - but I thought it would be interesting to share. They actually give the mix.

I didn't read everything so I'm not sure how stages it had to get these temps (2?) and I haven't found the diagrams yet - will look tonight if someone doesn't post them first.

[n00b 0f l337]

5 stages, unless the argons not being condensed. But even then the r14 cant possibly condense argon without insane pressures. Hmmmm I wonder if it makes a blend.... But what i find interesting is the similar amounts of each gas.

EDIT: Didnt cryo use some argon with the r14 to lower the BP but doesnt help to much with load?

[eshbach]

134a condensing 508a

yea, it will work, but there's not big cushion there... especially if the 134a temps go up under load... i guess that's what the 142b is for, but.... i'd be uncomfortable with that.

[Unknown_road]

the amount of gas in a system in system and load dependent. You can't make an autocascade now and trow these amounts of refrigerant in it and expect it to work flawless.

eshbach, it no problem for r134a to condens r508a/b, look at a PT-chart.

[Blaster]

this has already been discussed here

[n00b 0f l337]

Hehehe i get it 100% of the way...
Welcome to the land of the Polycold.

[jinu117]

LoL... I see someone else paid for the patent... other than me :P
Anyways, gas mixture looks to have huge mass on that one making me think it is probably for small environmental chamber. Yup, those guys were talking about alternative refrigerant for auto-c instead of "traditional" R123, R22, R23, R14, etc. Now, I really don't feel comfortable with some composition they talked about espeically R508. Maybe there is enough gap between R22 and R14 that partial separation of R508 (r23+r116) isn't big issue since R23 and R116 has very similar properties over all... (in ball park compared to other gases in there.
Only way to find out.... is to play with it I guess

[eshbach]

the amount of gas in a system in system and load dependent. You can't make an autocascade now and trow these amounts of refrigerant in it and expect it to work flawless.

eshbach, it no problem for r134a to condens r508a/b, look at a PT-chart.

i don't have a chart for 508 handy, but i thought it was something like 220 psi at -15...

with all those other gasses in there, i'd imagine the low side pressure could easily get fairly high. what temperature do you think you could hold with the 134a stage in that system?

i'm just saying i wouldn't feel totally comfortable with it. i'd always be wondering how well the 508 was being condensed.

[n00b 0f l337]

BTW most of you are looking at this the wrong way. This system has 2 stages if you can call it that, can go from idle to -150C in under a minute (not off to -150C, IDLE) and does not autocascade the way we autocascade.

If you want more info, search up the R134a/Argon myth on this forum.

[wdrzal]

Don't forget a patent just means you have the rights to your invention, it can be snake oil and not do a thing and you can get a patent. A patent is no gaureentee that it works.Its just gives you the rights so its not copied for a period of time. If it does work!!!

[Unknown_road]

BTW most of you are looking at this the wrong way. This system has 2 stages if you can call it that, can go from idle to -150C in under a minute (not off to -150C, IDLE) and does not autocascade the way we autocascade.

If you want more info, search up the R134a/Argon myth on this forum.

the r134a/argon myth all started out over an autocascade. Somebody saw a unit that said -150 or something and saw at the gas label r134a and argon (and forgot to mention to others). He didn't know what an autocascade was and with 1 compressor he assumed it was a blend.

2 stages? Does not autocascade the way we autocascade? Could you be less vague? saying we look at this the wrong way and then explain nothing isn't helpfull

[n00b 0f l337]

Eh I think more along the lines of simply showing a diagram wouldnt teach anyone anything. I'm thinking a bit abstratcly, maybe some updates later.

[Quasi]

Jinu - I didn't pay for it - just came across it here

If you read it all (which I haven't) you will find a part in it that mentions that the 744 and 14 are what travels to the final stage in this setup.

Never did find the diagrams referred to in the patent.

I mostly bring it up because it has ratios which is what everyone seemed to be looking for - "the magic ratios". But - of course - Unknown is right - the ratios will change if your HX's are different and cap tubes (or other metering devices) are different etc. You would have to change the ratios I would imagine if the system were setup differently.

That would make the diagrams nice wouldn't it? But I din't seem to be able to find the links to the drawings.

[Clemmaster]

It can't be a 5 stage autocascad because autoC can't work at so different low side pressures, espacially in last stage wich would mean that argon vaporises at 23 bar . And can't work at so different high side pressures too. If what quasi says is true, it might be a 3stages autoC :
1- Blend of R134a / R143a to increase a bit the HP
2- R508a
3- Blend of R14/Argon