Vacuum Pump question.

[wdrzal]

update how many compressors are we up to now ,2,3,4 or more.

[_HL4E_HalfLife_]

update how many compressors are we up to now ,2,3,4 or more.

just 2

[wdrzal]

any luck with two

[skate2snow]

Oh BTW... What you can do useful with a compressor, is doing a recovery unit.... not really hard, any size is good, and it doesnt really need to pull a deep vacuum.... Its useful for those who has limited refrigerant resources....

[wdrzal]

Oh BTW... What you can do useful with a compressor, is doing a recovery unit.... not really hard, any size is good, and it doesnt really need to pull a deep vacuum.... Its useful for those who has limited refrigerant resources....

this is correct, all early recovery units used hermetic compressors.

the industry is getting away from using them because you need to change the oil when you change refrigerent types. Most now are oiless.

[shinymod]

any results on this yet HL4E?

[_HL4E_HalfLife_]

any results on this yet HL4E?

Not really because today i just changed from paralell to series and we don't know just how fast it would remove the water from the bottle without acualy sucking the liquid water from the bottle u know what i mean? and its not very ez to make a 100% seal from a gauge hose to a bottle.

[shinymod]

ah, yeah. i can see that being a problem... well keep us informed wont you

[hatemi]

All you realy would need to do is get a sight glass and braze its other end shut and braze a schraeder to the remaining end. Then fill it with water just so that the water level is at the sight glass and not above when the thing is mounted vertically.

[_HL4E_HalfLife_]

Theres still the matter of how quickly a vacuum system would remove that water. A large sold amount of water may take many hours to remove compaired to mini droplets in a copper tube.

[n00b 0f l337]

Isnt that why you can crank up the MAP gas torch and lightly go over the tubes to melt it down?

[wdrzal]

the point of a large volume is so you can see it boil, like boiling water in a pot, if you can't lower the pressure enough to make that happen the pressure isn't low enough.

[n00b 0f l337]

Good point, but while its sucking down, you might as well use the time and melt the water on ur own.

[wdrzal]

you don't need to remove all the water just making it boil will prove the point, you should be able to make it boil in under 1 min, if not it never will.

[matttheniceguy]

Well I did it, boiled water at room temperature with regular compressors.

I made a vacume pump from two dirty old compressors I got from the scrap yard for free. They are connected in series.

I took a shrader valve with a stem, and wraped it with electrical tape until it fit snugly into a glass bottle. I put some grease on the tape and shoved it into the bottle. I connected the bottle to the pump with a manifolg gauge, turned on the pump, and a couple seconds later the water started to boil. The water is fresh from the tap, so it is actualy a few degrees below room temperature.

I made a video of the unit getting turned on and pulling a vacume, then the water boiling. I'll post it in a second, I just have to compress it a bit.

Edit:

Ok, it seems I can't upload anything over 200kb, so I can't upload much of the movie no matter how bad I make it look. Essentially the video shows the system turned of, manifold gauge reads 0. The system is turned on, manifold gauge drops to about 30"HG, and the water in the bottle begins to boil. The water temperature is 20 degrees through all of this, which is a bit below ambient. Here is a very bad looking 5 seconds of the video. If someone knows how I can post more of the video, or want's to host it, PM me.

My pump won't work as well as a real vacume pump, but for the price of a shrader valve and some brazing rod, it's pretty damn good.

[wdrzal]

Congradulations you just proved 2 compressors will work.what type are you using piston or rotary.

[matttheniceguy]

Both of them are piston. I was actually suprised at how easily it made the water boil. I threw the addapter for a bottle together in probably less than 2 minutes and just slapped everything else together. I can't say that I noticed any leaks, but I would be supprised if there wern't some very small ones. Even with the quick construction, the pump had no trouble boiling the water, and it only takes 10 seconds or so from the time you turn the compressors on until the boiling starts. Putting a marshmellow (sp?) in the bottle is also a lot of fun, although I don't think I will ever get it back out.

There is a little bit about the vacume pump at the end of this thread.

Is is just two small piston type R-12 compressors that I picked up from the Bin-O-Compressors at the scrap yeard, connected in series.

[wdrzal]

I will have to see if I can get a micron reading using 2 compressors. My micron gauge only reads below 2000 microns so not sure if the pressure will get that low.

[_HL4E_HalfLife_]

Hmm my water wasn't doing that when i tried pulling a vacuum in a bottle. What was ur ambient temp? Im in my bacement where its cool so im just wondering what room temp is needed to get the water to boil with 2 compressors in series.

[matttheniceguy]

I was boiling the water in my basement at night. The ambient air temperature was around 21 or 22 degrees, and the water temperature was a bit below this, around 20 degrees.

[_HL4E_HalfLife_]

I tried it again but this time a stuck a heater near the bottle for a min and next thing you know the water is bubbling.

BTW the temp in the room im building this was only 18.5c.

[expansionvalve]

Well, you got water to boil off, fair play well done.
What are the chances of someone testing a pair of compressors on a system with a micron guage?

[shinymod]

i would giggle so hard if 2 compressors pulled a 25 micron vacuum ^.^ of course they wont... but it'd be funny to see the so called "halfassed" method kick the ass of the "proper" method

[expansionvalve]

I would giggle too, I would buy that man a few beers lol

[wdrzal]

I would giggle too, I would buy that man a few beers lol

don't giggle yet, I hooked 2 compressors togeater and was not able to get a micron reading ,my meter starts at 2000. That alone does not prove 2 comprseeors won't work.

But more testing needs done.One could hook them to the low side of a system while conecting the bottle to the high side,then doing the same experiment. first to see if you can get it to boil.Then by trying to remove just a few drops of water fro the bottle on the other side of system.

lines losses &restrictions are critical in deep vacuum,just havig a condensor and evap in the loop may prove to much to overcome.but maybee not we'll see.