Vacuum Techniques

[wdrzal]

After I get all you guys working safely, then I will start on clean

you should assemble a refrigeration system like in a NASA clean room building a satellite.

[n00b 0f l337]

Some of these times I'm so happy your here Walt. Sounds good.

[Exahertz]

Yea me too. And now that you mention filters, i have heard of cleaning desiccants of their retained water by the use of deep vacuum and heat. would heating the filter/dryer durring a vacuum be helpful?

you should assemble a refrigeration system like in a NASA clean room building a satellite.

aww man... does that mean i need to ware the bunny suite too?

[n00b 0f l337]

Actually using a heat gun on the system can help moisture boil off.

[wdrzal]

I'll say this ,never heat with a torch as you can damage a filter/dryer or valve if the wrong part get hot.

Also never heat a filter dryer or you will evaporate the moisture you want it to hold
a heat gun on low to medium or a hair dryer for the tubing or compressor to help release moisture that has a stronger bond (surface tension) when on a metal surface than in free air (no bond)

my heat gun on high I can soft solder 1/2" ID plumbing tube

[Exahertz]

Also never heat a filter dryer or you will evaporate the moisture you want it to hold

you mean durring opperation, right? i would only do it while i have a vacuum pump hooked up, and probably never exceed 120F.

[wdrzal]

I would not heat a filter dryer at all. re-read post 30 I added to it

[sacha35]

I am a bit confused hear walt, why would you not heat the filter dryer, as I think I am right in saying that they contain Silica gel which allows it to absorb water/moisture readily, making it useful as a desiccant (drying agent).

And once saturated with water/moisture, the gel can be regenerated by heating to 150 °C (300 °F) for 1.5 hours per liter of gel.

I do understand about over heating the gel as it will pop" when exposed to heat above the recommended level.

But if there is anything that you could share with us on why you should not heat the filter dryer please do, as I am very interested in why this should not be done, I understand you want the dryer to hold any moisture in the system, but if you can dry it out when under vacuum would this not be better.

[wdrzal]

because there is not only desiccant in there, F/D are made by mixing desiccant with a fine grit and some adhesive and pressed into a filter element,where liquid or gas has to pass from inside to outside depending on design, over heating can damage that material.

you want the desiccant to trap the moisture and not release it, Do you think there is only 1 type a desiccant ???? what comes in shoe & electronics boxes?

some filters /dryers have replacable elements, I see tomorrow if I can find one the seal was broken and not used take a picture.

[sacha35]

because there is not only desiccant in there, F/D are made by mixing desiccant with a fine grit and some adhesive and pressed into a filter element,where liquid or gas has to pass from inside to outside depending on design, over heating can damage that material.

you want the desiccant to trap the moisture and not release it, Do you think there is only 1 type a desiccant ???? what comes in shoe & electronics boxes?

some filters /dryers have replacable elements, I see tomorrow if I can find one the seal was broken and not used take a picture.

Thanks Walt, I was not sure on this that is why I asked, if you could find out the info it would be great, as I think others and myself included would be better informed of this.

[wdrzal]

if you could find out the info it would be great, as I think others and myself included would be better informed of this.

You would be also better informed if you did the research your self. you maybe learn a Extra item or two that day.

Then come back and tell the forum what you learned that day,plus the extras while researching, related to this forum,just think if everyone did that..........


Forgot: There should not be enough moisture left after a Proper Evacuation to matter < 300 to 500 microns.

[- Feedback]

Does the vacuum process remove the moisture from the desiccant? At some point the desiccant becomes saturated and can no longer hold any more moisture. I'd guess that proper refrigerant handling practices would lead the filter to become clogged before the desiccant can saturate.

[sacha35]

You would be also better informed if you did the research your self. you maybe learn a Extra item or two that day.

Then come back and tell the forum what you learned that day,plus the extras while researching, related to this forum,just think if everyone did that..........


Forgot: There should not be enough moisture left after a Proper Evacuation to matter < 300 to 500 microns.

As you rightly stated Walt, i found this bit of useful information from Parker that i found very helpful and informative that might be of some use to others so i have listed the link to there site for all to have a look.

Link:http://www.parker.com/cig/catalogs/C...lterdryers.pdf

[Athanatos]

original core


replacement filter and rings


the filter is replaceable, the screen is permanent

[Exahertz]

When a system's charge has been recovered, and the F/D beeing used is a molecular siev type, should it be changed? because from what i understand, molecular siev (synthetic zeolite) filters are positivly charged and retain polar molocules like water very tightly. so when in a deep vacuum, would any of the water come out? unlike loose-filled copper/steel dryers which seems like water would readily evaporate.
or is this the wrong direction im going, should all filters always be changed right before vacuuming?

[wdrzal]

Does the vacuum process remove the moisture from the desiccant? At some point the desiccant becomes saturated and can no longer hold any more moisture. I'd guess that proper refrigerant handling practices would lead the filter to become clogged before the desiccant can saturate.

No, its designed to lock it in, that why you change filter/dryers not evacuate them.

[Exahertz]

heres a benchmark i did with the vacuum pumps i have.
A while back someone asked to see one of my pumps pull less than one micron.



Welch 8917 / Fisher Scientific Maxima C+
Two Stage Rotary Vane
With 1/2 hp Explosion Proof Motor



Total pull down time: 9 minuets
ultimate pressure: 2 microns
Noise level: moderate
Weight: 68 lbs

Welch / York 1402
Two Stage Rotary Vane
With 1 hp Motor




Total pull down time: 7 minuets
ultimate pressure: <1 micron
Noise level: High
Weight: 102 lbs

Welch 1400
Singel Stage Rotary Vane
With 1/2 hp Motor




Total pull down time: 5 minuets
ultimate pressure: 2 microns
Noise level: very low
Weight: 40 lbs

[Marvin]

nice vacuum pumps.
i wish i have one.

[n00b 0f l337]

Those are some strong ass pumps, how do they handle a single stage?

[wdrzal]

Those are some strong ass pumps, how do they handle a single stage?

That doesn't matter and you won't get no where near that low with a compressor with oil in it.

those are medical /lab/scientific grade pumps that have a 1" or larger inlet usually. notice how the gauge clamps on .

pobably about 10 grand or more in pumps not counting the electronic gauge.

[n00b 0f l337]

Whoa I'm just asking. He does build phase units, or is building one, so i'm wondering how long. Those units can be obtained in working condition, and needing a little bit of tender love for around $300.

[wdrzal]

Exahertz do you know why the one pump has a snow flake on it ?????

[wdrzal]

Those are some strong ass pumps, how do they handle a single stage?

That doesn't matter and you won't get no where near that low with a compressor with oil in it.

those are medical /lab/scientific grade pumps that have a 1" or larger inlet usually. notice how the gauge clamps on .

pobably about 10 grand or more in pumps not counting the electronic gauge.

[n00b 0f l337]

Double post error?

[Exahertz]

Exahertz do you know why the one pump has a snow flake on it ?????

Yes, it’s a Welch pump that has a York sticker on it for use with refrigeration systems…

However these pumps do have a very wide array of uses. The 1402/YORK pump is used a lot in phase unit evacuative vacuum systems. I get at least one customer a week asking questions about the 1402 that’s refrigeration related. A very similar pump (the 1397B-01) is used a lot in recovery systems as well. But many labs and medical industries use them too (they just don’t buy them through York).

As for connecting this pump to a gauge manifold, there is a NW/KF Flange - Hose Barb adapter:


or the idea way is to get a NW/KF Flange - 1/4" NPT(TF) adapter, then also get a 1/4" NPT(TM) - Flare adapter