Are you interested in mixture refrigerant in cryogenics

[gxhphh]

I am researching the mixture refrigerant in cryogenics. It seems to be a promising technology in the temperature range from -200 degree to 25 degree. Do you agree?

[Prof Sporlan]

The Prof recalls the correct term here is "autocascade" systems. He used to know an engineer at Revco Scientific who blended refrigerants so that he could achieve about a -150°F evaporator temperature on a single stage system.

[DaBit]

It is promisinng, but it relies a lot on 'black magic'. If you blend two refrigerants, pump them through a compressor, separate them and feed them to their respective evaporators, you cannot expect each of them to behave as the pure variant. This makes measuring and finetuning quite hard. Also, a change somewhere affects the entire system.

Getting these systems to operate over a wide range of environment and load conditions is not easy.

[norcool]

I am researching the mixture refrigerant in cryogenics. It seems to be a promising technology in the temperature range from -200 degree to 25 degree. Do you agree?
yes of course,we are doing som stuff with blend of methan ethan against
LNG condensation and gas cleaning, have nice day

[JTSTEN]

You want to know how to do this I can help I have been designing units capable of 4kW @ -120oC with ultimates of -160 oC

[Peter_1]

Jtsten,

Have you ever used the special scroll compressor of Copeland, designed for use with helium?
I posted some time ago a link here on RE.

If you're going as low as -120°C and even lower, is this with an autocascade system or with a conventional cascade setup? I suppose this is then at least a 3 stage cascade (surely for the -160°C application)

I service 2 autocascade systems from Polycold (US) on a vacuum metalising chamber (capacitor fabrication).
The first time they called me, I never heard before of an autocascade, I even didn't knew it was an autocascade.
And I never learned so much at a time on one single machine, in fact basically a simple machine.
It has 1 compressor of 10 HP, a watercooled condenser and a lot of capillary tubes and coppertubes inside a big foamed cube, 2 relays, and some SV's. That's all. But it cost +/- 35.000 to 40.000 Euros!

It was magic for me then: we learned in school that this was not possible in a conventional solution, especially in 1 stage. starting at 20°C and going to -100°C.

May I ask, in what application are these systems used? Medical machines for blood preservation perhaps.

And do you design/make only such a machines?

This still remains some sort of magical refrigeration for me. It's going far beyond that of what most of us are doing daily.

[JTSTEN]

I design these systems under the see s10tech.com principally these competed with the Polycodl systems although they are 20% more efficient. They despite being conceptually simple machines difficult to get to work sucessfully.

If you are interested in a specific application I would be interested in having an input on the design.

[waternut06]

hi, i am interested to know where i can purchase a phase separator. i am building a autocascade system using mixed refrigerants and i have problems finding a phase separator online. anyone has a clue where to begin? also, i am curious to know besides copeland compressor, which compressor may be suitable for my refrigerant mix?

[jinu117]

hi, i am interested to know where i can purchase a phase separator. i am building a autocascade system using mixed refrigerants and i have problems finding a phase separator online. anyone has a clue where to begin? also, i am curious to know besides copeland compressor, which compressor may be suitable for my refrigerant mix?

Oil separator should do the trick really. After all all you want to do is separate oil and liquid.

[jinu117]

Oil separator should do the trick really. After all all you want to do is separate oil and liquid.
--> can't seem to edit... i meant separate gas and liquid... gravity should do trick for it.
You could make can with copper wool in it for phase separator too. Let the gravity do the work basically.

[Polypete]

Scroll or reciprocating compressors of virtually any make will do the job. You need to be sure the compressor will be suitable for the refrigerants (and oil) you intend using though. What temperature are you trying to achieve, I assume this will be below -100 C. ?

[Gonzo]

Oil separator should do the trick really. After all all you want to do is separate oil and liquid.

Contact Temprite as they make high efficiency separators for cascade applications. :o

[ernestlin]

Oil separator should do the trick really. After all all you want to do is separate oil and liquid.
Actually, the "phase seperator" you mentioned is a stuff like "accumulator". And, the reciprocating compressor may be a better choice, there're a lots of previous successful examples.