how do i build a Refrigerant Recovery Unit

[EvoCarlos]

right so as you know im doing some playing with phase change atm but for my next project i would like to make a Refrigerant Recovery Unit so that i can reuse the gas and clean it in the process (it would also pass for a vac pump to lol)
i know the basic layout but where it all goes i dont know
you guys know a solution
carl.

[n00b 0f l337]

If your going to recover from a static unit, your going to need a compressor, oil separator, condenser, a good flare connecting filter, some access valves, and probably some hand valves or solenoids.
Diagram like this should work. The idea is your going to need to separate out the oil from the refrigerant.

[Xeon th MG Pony]

got it back wards nol. Oil sep befor condencer and good idea to have an oil sep on suction side too.

[n00b 0f l337]

With the size of the floated oil seps we got, I'd imagine with oil sep before you'd lose some refrigerant to the oil. This way you just have to have a good oil sep to separate refrigerant from oil right? Maybe your right.
Suction prob too, but at a bare minimum you don't necesarily need it. More need a bunch of access ports, hand valves, and filters so you can vac the recovery unit first to an acceptable micronity Maybe put a micron gauge on the low side at the access even.

[Xeon th MG Pony]

thats why you make a recovery unit for one refrigerant only when making them your self, they never get empty all ways leave some gas above atmosphere in the unit.

Need the oil sep BEFOR condensor for it to do any thing usefull, that is the fact of the matter.

[n00b 0f l337]

Ah okay! Revise that then Mines the other way, maybe I'll flip it.

[teyber]

evocarlos- if your going to vacuum with it too try to use a powerful rotary, two is a lot better then 1 for vacuuming.

xeon- oil sep on suction side, brings the oil back to where? the system being evacuated or...? im real tired atm so please forgive but if you use a decent oil sep, why should you only use it with 1 refrigerant? if you use a rotary, but use a oil sep, will it be OK for evacuations of HFC's?

ive been wanting to build a similar thing evocarlos (but minus the vacuum pump ) for reclamation but also for "cleaning" the refrigerant a bit (taking oil out). mainly because i have a couple blissfields, rechi's, and 2 cheapo floated oil seps

[wdrzal]

much of this was covered if you use the search function.......The main consideration is if you are using a hermetic compressor(then the compressor oil must match the system oil being recovered) or a much better solution is buying a modern oiless compressor/recovery unit. Then it can be used on any rerigerant.(within technical specs.)

[Duzter]

xeon- oil sep on suction side, brings the oil back to where? the system being evacuated or...? im real tired atm so please forgive but if you use a decent oil sep, why should you only use it with 1 refrigerant? if you use a rotary, but use a oil sep, will it be OK for evacuations of HFC's?

EDIT: Understood your question now. :P

Are you going to put a solenoid or hand valve on that oil return?

An oil sep is never 100% effective.

[Xeon th MG Pony]

evocarlos- if your going to vacuum with it too try to use a powerful rotary, two is a lot better then 1 for vacuuming.

xeon- oil sep on suction side, brings the oil back to where? the system being evacuated or...? im real tired atm so please forgive but if you use a decent oil sep, why should you only use it with 1 refrigerant? if you use a rotary, but use a oil sep, will it be OK for evacuations of HFC's?

ive been wanting to build a similar thing evocarlos (but minus the vacuum pump ) for reclamation but also for "cleaning" the refrigerant a bit (taking oil out). mainly because i have a couple blissfields, rechi's, and 2 cheapo floated oil seps

On the suction side the oil is disposed of, it stops the oil from the unit being recovered from mixing and or flooding the recovery unit.

[wdrzal]

I never seen a early recovery unit with a oil, separators. The hermetic compressors just used sight glasses and drains to remove the excess oil they recovered from a system.

in small systems ,especially cap tube ,the refrigerant is removed mostly in vapor form and little oil is removed from the original system.

Only when removing condensed (liquid)refrigerant like from receivers or holding tanks in larger systems is oil a real issue.

[Xeon th MG Pony]

I never seen a early recovery unit with a oil, separators. The hermetic compressors just used sight glasses and drains to remove the excess oil they recovered from a system.

in small systems ,especially cap tube ,the refrigerant is removed mostly in vapor form and little oil is removed from the original system.

Only when removing condensed (liquid)refrigerant like from receivers or holding tanks in larger systems is oil a real issue.

Righto eh? Sorry but oil foaming during rapid recovery kinda ensures oil gets taken up. Frankly the older designs sucked so I upgraded it! I've improved recovery time and quality with my design, all so helps prevent the machine from geting to warm during heavy use and not to mention less oil carry over

Such a simplistic addition yet so much good things come from it, just becuase made that way doesn't mean it can't be made better! After 10 to 15 fridges/freezers I can fill a small bucket with all the oil the suction sep catches!

So for a new commer the suction sep will afford them lee way as they learn and not to mention further improves on an old design!

Perhaps in most application it is not "needed" How ever it does greatly improve the design making it far more solid and harder to kill a unit when some one with no experiance plays with it! So I will say it is some thing that should be put on any DIY unit!

[Xeon th MG Pony]

http://www.xtremesystems.org/forums/...covery+machine

[EvoCarlos]

evocarlos- if your going to vacuum with it too try to use a powerful rotary, two is a lot better then 1 for vacuuming.

xeon- oil sep on suction side, brings the oil back to where? the system being evacuated or...? im real tired atm so please forgive but if you use a decent oil sep, why should you only use it with 1 refrigerant? if you use a rotary, but use a oil sep, will it be OK for evacuations of HFC's?

ive been wanting to build a similar thing evocarlos (but minus the vacuum pump ) for reclamation but also for "cleaning" the refrigerant a bit (taking oil out). mainly because i have a couple blissfields, rechi's, and 2 cheapo floated oil seps

well i was hoping that as the system im recovering was in a charged state i would not need to go mad with using the reclam unit as a vac but it would help lol if i can get my hands on a roto i will use but the normal hermectric comps is problly what i will get

If your going to recover from a static unit, your going to need a compressor, oil separator, condenser, a good flare connecting filter, some access valves, and probably some hand valves or solenoids.
Diagram like this should work. The idea is your going to need to separate out the oil from the refrigerant.

i can see the layout now but wher would all the valves go or shall i do a doodle and you can say yes or no

thats why you make a recovery unit for one refrigerant only when making them your self, they never get empty all ways leave some gas above atmosphere in the unit.

Need the oil sep BEFOR condensor for it to do any thing usefull, that is the fact of the matter.

is there no way to make the unit self priming like commercial units?

much of this was covered if you use the search function.......The main consideration is if you are using a hermetic compressor(then the compressor oil must match the system oil being recovered) or a much better solution is buying a modern oiless compressor/recovery unit. Then it can be used on any rerigerant.(within technical specs.)

so that said if im recovering R134a and r404/r507 id be ok with POE oil in the recovery unit buying a unit is out of the qusetion to much cost and i would much preffer to make it as then i can say i made this lol


on another note the main reasion for this thread i saw a unit on ebay but missed it i thought that makeing one cant be that hard here are some pics of the unit off ebay i missed

[EvoCarlos]

lol you've done this before nol havnt you

[Duzter]

Maybe something like this:

schräder valve > hand valve > maybe an accumulator here if you suck liquid out > compressor > condenser > filter > sight glas > hand valve > schräder



With accumulator:

[EvoCarlos]

thanks for the posts guys i will try and get hold of a compersser soon and do a build i will be doing lots of images so you can all see also i will be open to further sujestions when i start the build watch this space

also i have some 134a in a bottle that has air mixed in is there any way to remove the air and will the reclam process sort that out?

[n00b 0f l337]

Purify is a different process. You'd really need a phase separator then, remove the gaseous air from the liquid refrigerant a few times...

[Xeon th MG Pony]

thanks for the posts guys i will try and get hold of a compersser soon and do a build i will be doing lots of images so you can all see also i will be open to further sujestions when i start the build watch this space

also i have some 134a in a bottle that has air mixed in is there any way to remove the air and will the reclaim process sort that out?

throw it in the freezer over night, take it out and put gauges on it. purge it to atmosphere very slowly till the pressure matches the pt chart, if don slowly and care fully you'll lose no refrigerant, only the air will be released

(This is the approved method via Canadian ODP Laws of removing air from a tank)

[EvoCarlos]

Purify is a different process. You'd really need a phase separator then, remove the gaseous air from the liquid refrigerant a few times...

hows that work then nol?

throw it in the freezer over night, take it out and put gauges on it. purge it to atmosphere very slowly till the pressure matches the pt chart, if don slowly and care fully you'll lose no refrigerant, only the air will be released

(This is the approved method via Canadian ODP Laws of removing air from a tank)

im not quite sure what you mean xeon so what will the frezzing process do to the 134a / o2 ?
"purge it to atmosphere very slowly till the pressure matches the pt chart" could you provide me with more info

[Xeon th MG Pony]

freezing it just makes the refrigerant slower to boil off thus as you purge lends to les mixing, remember refrigerant is heavier then air, so all the air is sitting ontop of the R-134a gas. As we bleed off the air the R-134a will expand pushing the air off, as we do this our pressure tempriture relationship will again match saturated 134a.

[EvoCarlos]

freezing it just makes the refrigerant slower to boil off thus as you purge lends to les mixing, remember refrigerant is heavier then air, so all the air is sitting ontop of the R-134a gas. As we bleed off the air the R-134a will expand pushing the air off, as we do this our pressure tempriture relationship will again match saturated 134a.

ahh now i get it so the o2 sits on top of the gas
so a wid guess is the pressure a set value?
or is it like 0 psig making -15 for r134a?
or other random figure
will the same work for all gas or just 134a
on and thanks for the help

[wdrzal]

ahh now i get it so the o2 sits on top of the gas
so a wid guess is the pressure a set value?
or is it like 0 psig making -15 for r134a?
or other random figure
will the same work for all gas or just 134a
on and thanks for the help

First air is not O2 (oxygen) . Air contains about 20.9% oxygen(@ least @ my elevation around 1400' Above sea level.,78% nitrogen .o3% co2 and the rest is rare earth gases.

You need to study and understand pressure/temperature charts for each refrigerant/ gas.
If you know the pressure,you know the temperature,if you know the temperature you know the pressure. This applies to tanks or system that have at least 1% liquid present(the number is actualy lower but 1% is very little liquid and a safe rule of thumb.If no liquid is present the p/t chart is invalid.

you also need to understand the critical pressures and temperatures and triple points of each gas. figures are not random.

air has a specific gravity of 1,some refrigeration vapors(or pure gases) are heavier than air or greater than 1 and some are lighter than air ,less than 1. You need to consult physical properties of each specific refrigerant or gas. most MSDS sheets list these but not all list complete info.

[EvoCarlos]

First air is not O2 (oxygen) . Air contains about 20.9% oxygen(@ least @ my elevation around 1400' Above sea level.,78% nitrogen .o3% co2 and the rest is rare earth gases.

You need to study and understand pressure/temperature charts for each refrigerant/ gas.
If you know the pressure,you know the temperature,if you know the temperature you know the pressure. This applies to tanks or system that have at least 1% liquid present(the number is actualy lower but 1% is very little liquid and a safe rule of thumb.If no liquid is present the p/t chart is invalid.

you also need to understand the critical pressures and temperatures and triple points of each gas. figures are not random.

air has a specific gravity of 1,some refrigeration vapors(or pure gases) are heavier than air or greater than 1 and some are lighter than air ,less than 1. You need to consult physical properties of each specific refrigerant or gas. most MSDS sheets list these but not all list complete info.

yes air is not o2 but you knew exzacllly what i ment i have been up 18hours lol
i did look in to the pt for 134a on here --> http://www.engineeringtoolbox.com/re...nts-d_902.html
and from what it tells me the boiling point of 134a is -15 @ 14.7psia which is 0psigg on the gages is it?< am i right do i get a cookie

[EvoCarlos]

right will this do for an oilsep ?

the red line shows where the pipe goes to
oh and ive got to fill it with scouring pad when i get some