Xeon you basic understanding of recovery is fundamentally wrong. very little oil is removed from the system by a recovery machine,usually measured in PPM(parts per million) from 500 to 5000. oil does not vaporize so it stays in the system, most of the oil you will get is if recovering liquid refrigerant.but these systems are to small to contain much if any liquid when offQuote:
Originally Posted by xeon th MG Pony
In the real world recovered refrigerants are divided into 2 categories ,clean & contaminated, clean may cost a dollar a pound or less as it is much easier to recycle, contaminated refrigerants cost over 12.00 a pound in some places to turn in a bottle , turn in a bottle you think is clean then get a bill for 26 pounds x 12 dollars a pound for contaminated. That adds up.
But I realize guys in the forum are primely concerned with saving their expensive refrigerant. remove it,fix problem and re-use it.it best to draw it out in vapor form although slower,but little liquid is present in small systems and it can be recovered in vapor form to prevent removing very little of the oil.
Having oil seperators will only cause the refrigerant to go into solution with the oil, why would you want to remove the oil at all? if fact the opposite is what you want to do. I just wrote a long post a few months ago about how even that a system that is off & equalized in pressure,any liquid refrigerant will vaporize move toward the oil,condense then go into solution with the oil.most guys want to recover only clean refrigerant and leave the oil in the system.
if the oil is bad ,you deal with that after you recover the refrigerant.
Standards are given for the amount of moisture,oil & incondensable in ppm by weight and differ for different refrigerants that acceptable for clean recover refrigerant or contaminated..oil does not vaporize so elaborate separators are not needed and if they collect oil will do more harm than good as the refrigerant will migrate there. There are many factory designs of recovery machines that use hermetic compressors and how they work. the vapor extraction rate is slow so they use what is called "a push pull method" to remove the liquid first on larger systems, then you remove the vapor. These small system may not have no to very little liquid in them to start with when off.
below is previous post on refrigerant & oil from a few months ago,read point 1 & 2
Quote:
I don't have much time to explain right now ,
1, oil attracts liquid refrigerant even if compressor is off and pressure is equalized,liquid refrigerant will vaporize migrate to oil,condense & go in to "solution" with the oil, this is a complex subject as entropy lends its affect to solution.
2,refrigerant in "gas state" does not mix with oil well, thats why piping sizes must be so enough velocity is created to "sweep" it along. nominal is 700 FPM for horizontal & 1500FPM for vertical
just note the difference between a "solution" and a "Emulsion" the latter is when oil & water are put together, there is complete separation until agitated into a emulsion.Think salad dressing....... viniger & oil
since entropy affects solution ,a point in time @ a point in system @ a specific temperature is needed. plus manufacturer data is needed to determine how much of the refrigerant is in "solution with the oil". There are other variables as oil system design,is foaming occuring,etc,etc.........
