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Home > Archive > Home Repair forum > August 2005 > 500 microns? - then you are a HACK!!
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500 microns? - then you are a HACK!!
|
|
| papaya 2005-08-19, 4:21 pm |
| if you only pull 500 microns of vacuum for your customer, you are not
getting all of the water out and are going to be making hydrochloric acid
for them, so they can buy a new unit from you, Mr. Con Artist.
quit ripping off the customer and change your pump oil or buy a new pump and
start pumping with good enough equipment, and for a long enough time, to get
down to 50 - 75 microns for an hour.
if you don't understand what the oil has to do with the final amount of
vacuum, or don't understand what are "microns" or don't have a precision way
to measure them, PLEASE RETIRE, because YOU SUCK, you INCOMPETENT HACK
| |
| Travis Jordan 2005-08-19, 4:21 pm |
| papaya wrote:
> if you only pull 500 microns of vacuum for your customer, you are not
> getting all of the water out and are going to be making hydrochloric
> acid for them, so they can buy a new unit from you, Mr. Con Artist.
Most manufacturers installation instructions say evacuate to 350
microns, then insure that the vacuum holds for at least a minute after
closing off the vacuum pump. Their instructions (and their warranty)
are good enough for me.
| |
|
| In article <a9GdnTGHFsxPv5veRVn-jA@comcast.com>,
"papaya" <papaya@papaya.com> wrote:
> if you only pull 500 microns of vacuum for your customer, you are not
> getting all of the water out and are going to be making hydrochloric acid
> for them, so they can buy a new unit from you, Mr. Con Artist.
>
> quit ripping off the customer and change your pump oil or buy a new pump and
> start pumping with good enough equipment, and for a long enough time, to get
> down to 50 - 75 microns for an hour.
>
> if you don't understand what the oil has to do with the final amount of
> vacuum, or don't understand what are "microns" or don't have a precision way
> to measure them, PLEASE RETIRE, because YOU SUCK, you INCOMPETENT HACK
You're a uninformed dipstick who posts about things you don't know shit
about.
At 500 microns water boils at minus 12 degree's which is plenty to get
the water out.
At 50 microns you're boiling the oil out.
--
Paul's cat got a furball and kept saying weasel's name.
*Hack* *Hack* *hack*
| |
|
| Gentlemen
I do not want blow you bobble however I think
that you are depending far to much on micron gauge
am I? nut no I am not I have been doing refrigeration work
guess? for over 40 years and field work since 1969
first good mechanic must visualized ( presume lost of gas)
how refrigerant was lost if is on high side or low side
if is on high side take in consideration what it will take to
fix the leak or problem and go from there on, it could
need just half hour or couple hours that determine how long
you will keep system open and to get it fix.
Low side leak again examined problem was the unit running
with no refrigerant in the system or did unit shut down on safety
how long was it with out any refrigerant in it, all this things
must be taken in consideration, only then you can
decide how long you will need to have it on vacuum
low side could be from hour to overnight and more if it
happen that solid water got into system, first you must
purge it with nitrogen (GN2) try to blow out all water as
possible then and only then put it on vacuum.
Now micron gauge With reading on the gauge
of 100 MICRONS YOU CAN STILL HAVE WATER
IN THE SYSTEM? impossible I have news for you
It is possible! how? well while water boils at low pressures
but it ALSO FREEZES and once it get frozen it does not
boils any more. Procedure is to pump system down
for couple hours then purge the system with GN2
let it sit for hour with GN2 in it then put on vacuum again
this procedure you may have to do few times depend
on size of the unit it self. I would also recommend changing
of oil "filter drier must" open and clean oil separator if there
is one plus add oil filter on return line On POE system
oil change is must and do not put clean oil in until
you have evacuated system first.
and no you are not boiling oil out what you see is oil bubbling
you are taken out residue of gas and moisture
Good luck Dido say that
"Travis Jordan" <no.one@no.net> wrote in message
news:PYpNe.24917$0_.17057@fe04.news.easynews.com...
> papaya wrote:
>
> Most manufacturers installation instructions say evacuate to 350
> microns, then insure that the vacuum holds for at least a minute after
> closing off the vacuum pump. Their instructions (and their warranty)
> are good enough for me.
>
>
| |
| PrecisionMachinisT 2005-08-19, 7:21 pm |
|
"DiDo" <a.seput@verizon.net> wrote in message
news:BMrNe.128$IG2.84@trndny01...
> It is possible! how? well while water boils at low pressures
> but it ALSO FREEZES and once it get frozen it does not
> boils any more.
Frozen water changes directly from the solid into the vapor phase under low
pressure conditions, due to a phenomena known as 'sublimation'.....IOW, no
"boiling" is needed.
http://www.newton.dep.anl.gov/askas...3/chem03598.htm
--
SVL
| |
| ~^Johnny^~ 2005-08-19, 8:21 pm |
| -----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
On Fri, 19 Aug 2005 14:20:04 -0400, "papaya" <papaya@papaya.com>
wrote:
>if you only pull 500 microns of vacuum for your customer, you are
>not getting all of the water out and are going to be making
>hydrochloric acid for them,
Bull feathers. If you are making acid, it's because you are a hack,
but for different reasons: No nitrogen while brazing, no drier
change, etc...
no vacuum pump can purge all the acid without an oil change and
flush, once contamination of "burnt freon" has taken place.
Why do you think, back in the old days, some techs used to flush the
lines with R11, R13 or dichloromethane, after a hermetic burnout?
With a single-stage vacuum pump, a good idea is to triple evacuate,
anyway.
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--
-john
wide-open at throttle dot info
| |
| ~^Johnny^~ 2005-08-19, 8:21 pm |
| -----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
On Fri, 19 Aug 2005 21:01:21 GMT, "DiDo" <a.seput@verizon.net> wrote:
>well while water boils at low pressures
>but it ALSO FREEZES and once it get frozen it does not
>boils any more.
Poppycock.
That far below its triple point, H2O sublimes readily.
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--
-john
wide-open at throttle dot info
| |
| ~^Johnny^~ 2005-08-19, 8:21 pm |
| -----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
On Fri, 19 Aug 2005 15:32:50 -0700, ~^Johnny^~
<nospam@gyrogearloose.com> wrote:
> some techs used to flush the
>lines with R11, R13
^^^
Oops! Typo. That should be R113, of course.
Stupid spell checker...
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--
-john
wide-open at throttle dot info
| |
|
|
"PrecisionMachinisT" <precisionmachinist@hotmail.com> wrote in message
news:wKOdnfthAfFFypveRVn-rA@scnresearch.com...
>
> "DiDo" <a.seput@verizon.net> wrote in message
> news:BMrNe.128$IG2.84@trndny01...
>
>
Frozen water changes directly from the solid into the vapor phase under low
> pressure conditions, due to a phenomena known as 'sublimation'.....IOW, no
> "boiling" is needed.
>
keep on dreaming you will learn sooner or later
From Dido
> http://www.newton.dep.anl.gov/askas...3/chem03598.htm
>
> --
>
> SVL
>
>
| |
|
|
"bill" <bill@hvac2.com> wrote in message
news:bill-BC1DF6.15020719082005@news-rdr-02.ohiordc.rr.com...
> In article <a9GdnTGHFsxPv5veRVn-jA@comcast.com>,
> "papaya" <papaya@papaya.com> wrote:
>
>
> You're a uninformed dipstick who posts about things you don't know shit
> about.
> At 500 microns water boils at minus 12 degree's which is plenty to get
> the water out.
> At 50 microns you're boiling the oil out.
>
My dear freinds
who ever told you that, he or she better get
little more knowlage and experience
or is it what you saying that if I evacuate system to
10 microns I will pump all of the oil out of compressor
you are so nerow mined I do not why
I bother answering
From Dido
> --
>
>
>
> Paul's cat got a furball and kept saying weasel's name.
>
> *Hack* *Hack* *hack*
| |
|
| What are these fabulous 'microns' you speak of, and where may I obtain
them?
Are they expensive?
I must have some.
| |
|
| In article <hqmcg1d8k29173v8h8ni6t0c66ton1soeo@4ax.com>,
~^Johnny^~ <nospam@gyrogearloose.com> wrote:
> With a single-stage vacuum pump, a good idea is to triple evacuate,
> anyway.
A single stage pump cannot pull a vacuum that can remove moisture.
--
Paul's cat got a furball and kept saying weasel's name.
*Hack* *Hack* *hack*
| |
|
| In article <97uNe.1432$3%1.292@trndny08>, "DiDo" <a.seput@verizon.net>
wrote:
> My dear freinds
> who ever told you that, he or she better get
> little more knowlage and experience
> or is it what you saying that if I evacuate system to
> 10 microns I will pump all of the oil out of compressor
> you are so nerow mined I do not why
> I bother answering
> From Dido
Dildo YOU need to do some reading.
--
Paul's cat got a furball and kept saying weasel's name.
*Hack* *Hack* *hack*
| |
|
| In article <IUtNe.29$rA2.28@trndny02>, "DiDo" <a.seput@verizon.net>
wrote:
> Frozen water changes directly from the solid into the vapor phase under low
> keep on dreaming you will learn sooner or later
> From Dido
Cite your sources dildo. Or do you just pull shit out of your XXX like
weasel does?
--
Paul's cat got a furball and kept saying weasel's name.
*Hack* *Hack* *hack*
| |
|
| Answer one question
on how many units did you work that do run at
-85 degrees Fahrenheit and must make -100
yes you can use R-11, R-114 and few others
but field person must use what is readily available
and don't come telling people what is in book
but from your own experience work done.
ANYTHING I POST I HAVE ALREADY DONE IT
I do not IMAGINE IT I did it
I suggest not only to you but to any that read this
get some books on ultra low temperature and start
reading before you come back to me
with some stupid answers that you have no idea
of what the heck you are talking about it is bloody disgrace
that some of you. servicing air conditioners and nothing ales
as long as you being doing this and you think you are expert
on refrigeration, with answers and posting you gave
if I was to gave you to clean my bathroom I strongly believe
that my bathroom would be insulted,
and Johnny this does not only pretend to you.
You have big company
"~^Johnny^~" <nospam@gyrogearloose.com> wrote in message
news:hqmcg1d8k29173v8h8ni6t0c66ton1soeo@4ax.com...
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> On Fri, 19 Aug 2005 14:20:04 -0400, "papaya" <papaya@papaya.com>
> wrote:
>
>
> Bull feathers. If you are making acid, it's because you are a hack,
> but for different reasons: No nitrogen while brazing, no drier
> change, etc...
>
> no vacuum pump can purge all the acid without an oil change and
> flush, once contamination of "burnt freon" has taken place.
>
> Why do you think, back in the old days, some techs used to flush the
> lines with R11, R13 or dichloromethane, after a hermetic burnout?
>
> With a single-stage vacuum pump, a good idea is to triple evacuate,
> anyway.
>
> -----BEGIN PGP SIGNATURE-----
> Version: PGP 7.1
>
> iQA/AwUBQwZeEAIk7T39FC4ZEQKCSwCeNrx4o/8DKt3InpXwjuExsB9IRUMAoPmF
> P+t1cifpZQANo5m/EmaVVsKL
> =O/jR
> -----END PGP SIGNATURE-----
> --
> -john
> wide-open at throttle dot info
| |
| Dr. Hardcrab 2005-08-19, 10:21 pm |
|
"bill" <bill@hvac2.com> wrote in message
news:bill-8E17D6.20323819082005@news-rdr-02.ohiordc.rr.com...
> In article <IUtNe.29$rA2.28@trndny02>, "DiDo" <a.seput@verizon.net>
> wrote:
>
>
> Cite your sources dildo. Or do you just pull shit out of your XXX like
> weasel does?
JEEBUS CHRIST ON A CRACKER!!!!!!
This damn place is turning into alt.hvac........
| |
| pjm@see_my_sig_for_address.com 2005-08-19, 11:21 pm |
| On Sat, 20 Aug 2005 01:15:53 GMT, "Dr. Hardcrab"
<drhardcrab@hotmail.SPAMcom> wrote:
>
>"bill" <bill@hvac2.com> wrote in message
>news:bill-8E17D6.20323819082005@news-rdr-02.ohiordc.rr.com...
>
>JEEBUS CHRIST ON A CRACKER!!!!!!
>
>This damn place is turning into alt.hvac........
>
Shee-it !!!! :-(
Click here every day to feed an animal that needs you today !!!
http://www.theanimalrescuesite.com/
Paul ( pjm @ pobox . com ) - remove spaces to email me
'Some days, it's just not worth chewing through the restraints.'
'With sufficient thrust, pigs fly just fine.'
HVAC/R program for Palm PDA's
Free demo now available online http://pmilligan.net/palm/
| |
| JohnR66 2005-08-19, 11:21 pm |
| "Dr. Hardcrab" <drhardcrab@hotmail.SPAMcom> wrote in message
news:dvvNe.2316$137.1018@trnddc08...
>
> "bill" <bill@hvac2.com> wrote in message
> news:bill-8E17D6.20323819082005@news-rdr-02.ohiordc.rr.com...
>
> JEEBUS CHRIST ON A CRACKER!!!!!!
>
> This damn place is turning into alt.hvac........
>
It is. Check the cross posting...
| |
|
| In article <D1vNe.131$Fq2.90@trndny03>, "DiDo" <a.seput@verizon.net>
wrote:
> Answer one question
> on how many units did you work that do run at
> -85 degrees Fahrenheit and must make -100
> yes you can use R-11, R-114 and few others
> but field person must use what is readily available
> and don't come telling people what is in book
> but from your own experience work done.
> ANYTHING I POST I HAVE ALREADY DONE IT
> I do not IMAGINE IT I did it
> I suggest not only to you but to any that read this
> get some books on ultra low temperature and start
> reading before you come back to me
> with some stupid answers that you have no idea
> of what the heck you are talking about it is bloody disgrace
> that some of you. servicing air conditioners and nothing ales
> as long as you being doing this and you think you are expert
> on refrigeration, with answers and posting you gave
> if I was to gave you to clean my bathroom I strongly believe
> that my bathroom would be insulted,
> and Johnny this does not only pretend to you.
> You have big company
You aren't the only one who works on low temp refrigeration.
You can't spew bullshit and not be called on it. Cite your sources dildo.
Or STFU.
There. You've been called on it. Pony up or pussy out.
--
Paul's cat got a furball and kept saying weasel's name.
*Hack* *Hack* *hack*
| |
|
| PrecisionMachinisT wrote:
> "DiDo" <a.seput@verizon.net> wrote in message
> news:BMrNe.128$IG2.84@trndny01...
>
>
>
>
> Frozen water changes directly from the solid into the vapor phase under low
> pressure conditions, due to a phenomena known as 'sublimation'.....IOW, no
> "boiling" is needed.
>
> http://www.newton.dep.anl.gov/askas...3/chem03598.htm
>
> --
>
> SVL
>
>
Sam,
I think Dido is talking about when you have a evap coil exposed to other
cold temps within a running freezer.. a common occurence in the
commercial world.
This is what the man meant, I believe.
Jake
| |
| Noon-Air 2005-08-20, 1:21 am |
| Dude, I got no idea what you are babbling on about.
reply below
"papaya" <papaya@papaya.com> wrote in message
news:a9GdnTGHFsxPv5veRVn-jA@comcast.com...
> if you only pull 500 microns of vacuum for your customer, you are not
> getting all of the water out and are going to be making hydrochloric acid
> for them, so they can buy a new unit from you, Mr. Con Artist.
Maybe if your pump is too big...
> quit ripping off the customer and change your pump oil or buy a new pump
> and start pumping with good enough equipment, and for a long enough time,
> to get down to 50 - 75 microns for an hour.
Umm..... you better check the specs on *new* pumps... they are rated for and
tested for a *maximum* of 50 microns
> if you don't understand what the oil has to do with the final amount of
> vacuum, or don't understand what are "microns" or don't have a precision
> way to measure them, PLEASE RETIRE, because YOU SUCK, you INCOMPETENT HACK
Do it right with N2 purge while brazing, new filter dryer, and use a small
vacuum pump(4 - 6 CFM) with new oil, and you won't have a problem drawing
down to between 300 - 400 microns. Too big of a vacuum pump will cause too
fast of a draw-down and cause any water in the system to turn to ice. OTOH,
If you are really gonna be that anal and have the time to leave your vacuum
pump on a resi system for 2 days while trying to draw it down to 50 microns,
then by all means, knock yourself out.
| |
|
| On 19 Aug 2005 16:59:55 -0700, "Matt" <mattmorgan64@msn.com> wrote:
>What are these fabulous 'microns' you speak of, and where may I obtain
>them?
>
>Are they expensive?
>
>I must have some.
don't new a/c installs have to be evacuated to 300 microns? in
automotive we use 600 microns, but we also use 0-rings instead of
sweated fittings.
I'd really like to see the vaccuum pump that will pull it to 50
microns.
Chip
| |
| PrecisionMachinisT 2005-08-20, 1:21 am |
|
"DiDo" <a.seput@verizon.net> wrote in message
news:IUtNe.29$rA2.28@trndny02...
>
> "PrecisionMachinisT" <precisionmachinist@hotmail.com> wrote in message
> news:wKOdnfthAfFFypveRVn-rA@scnresearch.com...
>
>
> Frozen water changes directly from the solid into the vapor phase under
low
no[color=darkred]
> keep on dreaming you will learn sooner or later
> From Dido
>
Well, I spose it was rather unrealistic of me to expect an illiterate
fuckwit such as yourself to actually comprehend much if any of the
information contained within the link I posted, and I guess I might be one
of only a few that actually paid much attention in 9th grade science
classes.
Still, appreciate if you don't send me anymore email on the topic.
--
SVL
| |
| Dr. Hardcrab 2005-08-20, 1:21 am |
|
"JohnR66" <nospam@att.net> wrote in message
news:gewNe.115707$5N3.24882@bgtnsc05-news.ops.worldnet.att.net...
> "Dr. Hardcrab" <drhardcrab@hotmail.SPAMcom> wrote in message
> news:dvvNe.2316$137.1018@trnddc08...
> It is. Check the cross posting...
DUH!
(I missed that)
| |
| PrecisionMachinisT 2005-08-20, 1:21 am |
|
"Jake" <jkelleyus@insightbb.com> wrote in message
news:CDwNe.48754$084.28178@attbi_s22...
> PrecisionMachinisT wrote:
low[color=darkred]
no[color=darkred]
> Sam,
>
> I think Dido is talking about when you have a evap coil exposed to other
> cold temps within a running freezer.. a common occurence in the
> commercial world.
>
> This is what the man meant, I believe.
>
Jake,
Doesn't matter--next time it snows, watch your outside temp real close, and
take note of any period over several days, or perhaps up to a week where the
temp stays constantly below freezing....notice that the snow 'just kinda
dissapears'....given enough time, it will eventually dissapear altogether,
without ever reaching a temp above freezing, and without rain falling on it,
etc.....now note that this process speeds up considerably at pressures below
atmospheric.
--
SVL
| |
|
| > Jake,
>
> Doesn't matter--next time it snows, watch your outside temp real close, and
> take note of any period over several days, or perhaps up to a week where the
> temp stays constantly below freezing....notice that the snow 'just kinda
> dissapears'....given enough time, it will eventually dissapear altogether,
> without ever reaching a temp above freezing, and without rain falling on it,
> etc.....now note that this process speeds up considerably at pressures below
> atmospheric.
>
> --
>
> SVL
>
>
OK, I buy that! The info in your article also said "If you've got a
week" or something similar. I don't think a tech in the field has that
kind of time, so perhaps that's what Dido is addressing.
I've seen ice develop in commercial Vacuum systems, and it does not
dissipate easily... it takes a long and slow pull. (NO one please make a
inference from this given my comments below)...
I *do* understand the pressure relationship, believe it or not....
BTW, I think I was either drunk or high in 9th grade science class...or
perhaps making passes at the lovely 'Tracey' that sat next to me, as I
recall. Tracey ended up on crack or welfare, or both, I think...
Oh, I got an A in Science... maybe it was Math, or English... or
something (-;.....
ahhhh... the '70's. DON'T TRY THIS NOW, KIDS!
Jake
| |
| Anthony Berlin 2005-08-20, 2:21 am |
| WTF did you just say? Better leave that alcohol alone, shit's burning the
cells faster than you're makin' 'em.
"DiDo" <a.seput@verizon.net> wrote in message
news:BMrNe.128$IG2.84@trndny01...
> Gentlemen
> I do not want blow you bobble however I think
> that you are depending far to much on micron gauge
> am I? nut no I am not I have been doing refrigeration work
> guess? for over 40 years and field work since 1969
> first good mechanic must visualized ( presume lost of gas)
> how refrigerant was lost if is on high side or low side
> if is on high side take in consideration what it will take to
> fix the leak or problem and go from there on, it could
> need just half hour or couple hours that determine how long
> you will keep system open and to get it fix.
> Low side leak again examined problem was the unit running
> with no refrigerant in the system or did unit shut down on safety
> how long was it with out any refrigerant in it, all this things
> must be taken in consideration, only then you can
> decide how long you will need to have it on vacuum
> low side could be from hour to overnight and more if it
> happen that solid water got into system, first you must
> purge it with nitrogen (GN2) try to blow out all water as
> possible then and only then put it on vacuum.
> Now micron gauge With reading on the gauge
> of 100 MICRONS YOU CAN STILL HAVE WATER
> IN THE SYSTEM? impossible I have news for you
> It is possible! how? well while water boils at low pressures
> but it ALSO FREEZES and once it get frozen it does not
> boils any more. Procedure is to pump system down
> for couple hours then purge the system with GN2
> let it sit for hour with GN2 in it then put on vacuum again
> this procedure you may have to do few times depend
> on size of the unit it self. I would also recommend changing
> of oil "filter drier must" open and clean oil separator if there
> is one plus add oil filter on return line On POE system
> oil change is must and do not put clean oil in until
> you have evacuated system first.
> and no you are not boiling oil out what you see is oil bubbling
> you are taken out residue of gas and moisture
> Good luck Dido say that
>
> "Travis Jordan" <no.one@no.net> wrote in message
> news:PYpNe.24917$0_.17057@fe04.news.easynews.com...
>
>
| |
| Richard J Kinch 2005-08-20, 3:21 am |
| PrecisionMachinisT writes:
> Frozen water changes directly from the solid into the vapor phase
> under low pressure conditions, due to a phenomena known as
> 'sublimation'
No, not without heat added.
No, not when the water is hydrating another substance.
| |
| Richard J Kinch 2005-08-20, 4:21 am |
| bill writes:
> At 500 microns water boils at minus 12 degree's which is plenty to get
> the water out.
It will not vaporize without the addition of heat.
It will not vaporize if it is bound to another substance.
| |
| PrecisionMachinisT 2005-08-20, 4:21 am |
|
"Richard J Kinch" <kinch@truetex.com> wrote in message
news:Xns96B816E6A47B1someconundrum@216.196.97.131...
> PrecisionMachinisT writes:
>
>
> No, not without heat added.
Dont be a fuckwit.
_Pressure_= heat.....
>
> No, not when the water is hydrating another substance.
>
And so now pray tell just what the hell is this mysterious 'substance' youve
added ( to the case in point)
Hmmm.......
Given a vacuum with some small amount of frozen water in it........will it
( eventually ) sublime or no ???
--
SVL
| |
| pjm@see_my_sig_for_address.com 2005-08-20, 8:21 am |
| On Sat, 20 Aug 2005 01:18:11 -0500, Richard J Kinch
<kinch@truetex.com> wrote:
>bill writes:
>
>
>It will not vaporize without the addition of heat.
>
>It will not vaporize if it is bound to another substance.
What line of work are you in, exactly ? I know it ain't HVAC
.....
Click here every day to feed an animal that needs you today !!!
http://www.theanimalrescuesite.com/
Paul ( pjm @ pobox . com ) - remove spaces to email me
'Some days, it's just not worth chewing through the restraints.'
'With sufficient thrust, pigs fly just fine.'
HVAC/R program for Palm PDA's
Free demo now available online http://pmilligan.net/palm/
| |
| nicksanspam@ece.villanova.edu 2005-08-20, 9:21 am |
| PrecisionMachinisT <precisionmachinist@hotmail.com> wrote:
>_Pressure_= heat.....
Learn something new every day around here.
Nick
| |
| pjm@see_my_sig_for_address.com 2005-08-20, 9:21 am |
| On 20 Aug 2005 07:57:28 -0400, nicksanspam@ece.villanova.edu wrote:
>PrecisionMachinisT <precisionmachinist@hotmail.com> wrote:
>
>
>Learn something new every day around here.
>
>Nick
Don't you have a big nasty program for that one ? :-)
Click here every day to feed an animal that needs you today !!!
http://www.theanimalrescuesite.com/
Paul ( pjm @ pobox . com ) - remove spaces to email me
'Some days, it's just not worth chewing through the restraints.'
'With sufficient thrust, pigs fly just fine.'
HVAC/R program for Palm PDA's
Free demo now available online http://pmilligan.net/palm/
| |
| papaya 2005-08-20, 10:21 am |
| > don't new a/c installs have to be evacuated to 300 microns? in
> automotive we use 600 microns, but we also use 0-rings instead of
> sweated fittings.
> I'd really like to see the vaccuum pump that will pull it to 50
> microns.
> Chip
" in automotive we use 600 microns"
EXCUSE ME???
WHAT KIND OF BULLSHIT "MECHANIC" ARE YOU??
I am in automotive A/C, and we use 50-75 microns vacuum, if you use 600 then
you are screwing your customers, and blaming O-rings for your insufficient
vacuum is ridiculous, what the hell do you think the seals your manifold
gauge set, hoses, and all other equipment are made up of?
you need to be in the special olympics, rather than working on automotive
A/C, you stupid retard hack
| |
|
|
"bill" <bill@hvac2.com> wrote in message
news:bill-12A288.22231319082005@news-rdr-02.ohiordc.rr.com...
> In article <D1vNe.131$Fq2.90@trndny03>, "DiDo" <a.seput@verizon.net>
> wrote:
>
>
> You aren't the only one who works on low temp refrigeration.
No I am not you are absulutly right
Good luck Dido
> You can't spew bullshit and not be called on it. Cite your sources dildo.
> Or STFU.
> There. You've been called on it. Pony up or pussy out.
>
> --
>
>
>
> Paul's cat got a furball and kept saying weasel's name.
>
> *Hack* *Hack* *hack*
| |
|
| In article <pfGNe.132$p32.83@trndny06>, "DiDo" <a.seput@verizon.net>
wrote:
[color=darkred]
>
> No I am not you are absulutly right
> Good luck Dildo
>
>
So you're going to pussy out I take it?
--
Paul's cat got a furball and kept saying weasel's name.
*Hack* *Hack* *hack*
| |
| Stormin Mormon 2005-08-20, 11:21 pm |
| Ah, an excellent question. A micron is a stone that is mined in South
Africa.
--
Christopher A. Young
Do good work.
It's longer in the short run
but shorter in the long run.
..
..
"Matt" <mattmorgan64@msn.com> wrote in message
news:1124495995.342167.139020@f14g2000cwb.googlegroups.com...
What are these fabulous 'microns' you speak of, and where may I obtain
them?
Are they expensive?
I must have some.
| |
| Richard J Kinch 2005-08-21, 2:21 am |
| PrecisionMachinisT writes:
[color=darkred]
> And so now pray tell just what the hell is this mysterious 'substance'
> youve added ( to the case in point)
Dessicants, lubricants, contaminants. They will not release water of
hydration just because you apply a vacuum at ambient temperatures.
Neither will slugs of free water trapped in lines, without either a lot
of time or an external heating source.
> Given a vacuum with some small amount of frozen water in
> it........will it ( eventually ) sublime or no ???
Only in proportion to the heat added. It *will not* sublime at all if
there is no heat added, even in a perfect vacuum.
The universe is full of solid water in the near-perfect vacuum of space.
Comets are an example.
Commercial food freeze-drying apparatus provide a circulating heat
medium on the trays. You can't just shove hunks of wet food in a vacuum
chamber and pump it down to freeze-dry it, practically speaking.
Neither can you dry out a wet HVAC system by leaving it on a vacuum. I
know this is an article of faith in the HVAC trade, but it is a myth
beacuse the tradesmen only learn a shallow smattering of chemistry and
thermodynamics. And they just want to believe it.
| |
| gfretwell@aol.com 2005-08-21, 3:21 am |
| On Sun, 21 Aug 2005 00:07:30 -0500, Richard J Kinch
<kinch@truetex.com> wrote:
>The universe is full of solid water in the near-perfect vacuum of space.
>Comets are an example.
I am not sure where you live but it is about 600 degrees F warmer than
"space " on earth, even in the winter. There is plenty of available
heat to sublimate water.
| |
| Richard J Kinch 2005-08-21, 3:21 am |
| > I am not sure where you live but it is about 600 degrees F warmer than
> "space " on earth, even in the winter. There is plenty of available
> heat to sublimate water.
Repeat after me: temperature is not heat.
| |
| PrecisionMachinisT 2005-08-21, 3:21 am |
|
"Richard J Kinch" <kinch@truetex.com> wrote in message
news:Xns96B9B6DE3209someconundrum@216.196.97.131...
> PrecisionMachinisT writes:
>
>
> Only in proportion to the heat added. It *will not* sublime at all if
> there is no heat added, even in a perfect vacuum.
>
Ignore the entire concept of latent heat if its convenient to you then....
Point being is the heat was already added or subtrcated from the sytstem
before or after the phase change took place........still, its pressure
causing the actual change to occur.
Im done, your a fuckwit and my opinion still stands.
>
> The universe is full of solid water in the near-perfect vacuum of space.
> Comets are an example.
>
And I've heard that it's fucking hotter than hell out there, too...
--
SVL
| |
| Richard J Kinch 2005-08-21, 4:21 am |
| PrecisionMachinisT writes:
> Ignore the entire concept of latent heat if its convenient to you
> then....
Haven't ignored anything.
(Regardless, I suspect you mean sensible heat.)
> Point being is the heat was already added or subtrcated from the
> sytstem before or after the phase change took place.
The heat initially present in the water itself, or something intimately
in contact with it, will vaporize very little water, and in practice the
ambient heat will not flow in quickly (the vacuum being an insulator).
And this only applies to free water. Ordinary vacuum dessication does
not work for water bound in something like a silica gel dessicant, or
entrained in the oil, or hydrating contaminants.
A lot of people have been taught the pseudo-scientific myth that "water
boils in a vacuum" in some magic sense that it doesn't in the
atmosphere. The truth is that water vaporizes in a vacuum or in the
atmosphere the same way: *only* because you add heat. In the same
sense, water doesn't boil at 212 deg F, it boils because you add more
heat after it is at 212 deg F.
Another related myth is that if *you* were put into a vacuum, your body
would explode or your "blood would boil". Pure bunk.
Another popular (and yes, even in the HVAC trade) myth is "saturation"
of air with humidity, that the moisture is carried or dissolved in the
air, and that it "saturates" like a solution of salt in water.
| |
| PrecisionMachinisT 2005-08-21, 5:21 am |
|
"Richard J Kinch" <kinch@truetex.com> wrote in message
news:Xns96B9211DA80F3someconundrum@216.196.97.131...
> PrecisionMachinisT writes:
>
>
> Haven't ignored anything.
>
> (Regardless, I suspect you mean sensible heat.)
>
>
> The heat initially present in the water itself, or something intimately
> in contact with it, will vaporize very little water, and in practice the
> ambient heat will not flow in quickly (the vacuum being an insulator).
>
> And this only applies to free water. Ordinary vacuum dessication does
> not work for water bound in something like a silica gel dessicant, or
> entrained in the oil, or hydrating contaminants.
>
> A lot of people have been taught the pseudo-scientific myth that "water
> boils in a vacuum" in some magic sense that it doesn't in the
> atmosphere. The truth is that water vaporizes in a vacuum or in the
> atmosphere the same way: *only* because you add heat. In the same
> sense, water doesn't boil at 212 deg F, it boils because you add more
> heat after it is at 212 deg F.
>
> Another related myth is that if *you* were put into a vacuum, your body
> would explode or your "blood would boil". Pure bunk.
>
> Another popular (and yes, even in the HVAC trade) myth is "saturation"
> of air with humidity, that the moisture is carried or dissolved in the
> air, and that it "saturates" like a solution of salt in water.
Obviously then , some part of "Im done, your a fuckwit and my opinion still
stands" has apparently still escaped your attention.
Bye bye idiot troll.........
--
SVL
| |
| Joshua Putnam 2005-08-21, 6:21 am |
| In article <1124495995.342167.139020@f14g2000cwb.googlegroups.com>,
mattmorgan64@msn.com says...
> What are these fabulous 'microns' you speak of, and where may I obtain
> them?
In case this was a genuine question, one micron = 1/25,400 inch.
In the case of vacuums, that's inches of mercury, just like in a
barometer.
--
josh@phred.org is Joshua Putnam
<http://www.phred.org/~josh/>
Braze your own bicycle frames. See
<http://www.phred.org/~josh/build/build.html>
| |
| TURTLE 2005-08-21, 2:21 pm |
|
"PrecisionMachinisT" <precisionmachinist@hotmail.com> wrote in message
news:UfudnXEM3PQbO5veRVn-qA@scnresearch.com...
>
> "Jake" <jkelleyus@insightbb.com> wrote in message
> news:CDwNe.48754$084.28178@attbi_s22...
> low
> no
>
> Jake,
>
> Doesn't matter--next time it snows, watch your outside temp real close, and
> take note of any period over several days, or perhaps up to a week where the
> temp stays constantly below freezing....notice that the snow 'just kinda
> dissapears'....given enough time, it will eventually dissapear altogether,
> without ever reaching a temp above freezing, and without rain falling on it,
> etc.....now note that this process speeds up considerably at pressures below
> atmospheric.
>
> --
>
> SVL
>
This is Turtle.
i see the example all the time with ice cub trays all the time. Fill a ice cube
tray with water and let them freeze real good and then keep them in the freezer
for 1 years. You will come back and find all the ice gone out of the ice cube
tray. I call it freezer evaperation or called freezer burning the ice. This
dehydration takes all the moisture out of food product and is called freezer
burn.
TURTLE
| |
| gfretwell@aol.com 2005-08-21, 3:21 pm |
| On Sun, 21 Aug 2005 00:41:04 -0500, Richard J Kinch
<kinch@truetex.com> wrote:
>
>Repeat after me: temperature is not heat.
Repeat after me, a gas at a given temperature (ambient air) is heat.
| |
| PrecisionMachinisT 2005-08-21, 3:21 pm |
|
<gfretwell@aol.com> wrote in message
news:epdhg11mb57ormuda429v73ctpk4m2vd77@4ax.com...
> On Sun, 21 Aug 2005 00:41:04 -0500, Richard J Kinch
> <kinch@truetex.com> wrote:
>
>
> Repeat after me, a gas at a given temperature (ambient air) is heat.
See cat...notice cat has a tail....pull on cat's tail........
Repeat until bored.
--
SVL
| |
| pjm@see_my_sig_for_address.com 2005-08-21, 3:21 pm |
| On Sun, 21 Aug 2005 10:46:35 -0700, "PrecisionMachinisT"
<precisionmachinist@hotmail.com> wrote:
>
><gfretwell@aol.com> wrote in message
>news:epdhg11mb57ormuda429v73ctpk4m2vd77@4ax.com...
>
>See cat...notice cat has a tail....pull on cat's tail........
>
>Repeat until bored.
See cow.
See cow udders.
Pull cow udders.
Get milk.
If cow only have one udder, get cream.
Click here every day to feed an animal that needs you today !!!
http://www.theanimalrescuesite.com/
Paul ( pjm @ pobox . com ) - remove spaces to email me
'Some days, it's just not worth chewing through the restraints.'
'With sufficient thrust, pigs fly just fine.'
HVAC/R program for Palm PDA's
Free demo now available online http://pmilligan.net/palm/
| |
| PrecisionMachinisT 2005-08-21, 4:21 pm |
|
<pjm@see_my_sig_for_address.com> wrote in message
news:peghg1dr05s67edsek37jla2fjl4otm61n@4ax.com...
>
> If cow only have one udder, get cream.
>
Bull.
--
SVL
| |
| ~^Johnny^~ 2005-08-21, 5:21 pm |
| -----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
On Sun, 21 Aug 2005 02:15:25 -0500, Richard J Kinch
<kinch@truetex.com> wrote:
> The truth is that water vaporizes in a vacuum or in the
>atmosphere the same way: *only* because you add heat. In the same
>sense, water doesn't boil at 212 deg F, it boils because you add
>more heat after it is at 212 deg F.
Then you're all wet.
-----BEGIN PGP SIGNATURE-----
Version: PGP 7.1
iQA/AwUBQwjejAIk7T39FC4ZEQIO9QCguHSRV5tUO06ZeIVnzzonnEDuqsEAnjJ1
Imv1in/cDv3fIdImpY7Mj8dN
=ZMXn
-----END PGP SIGNATURE-----
--
-john
wide-open at throttle dot info
| |
| Joseph 2005-08-21, 7:21 pm |
|
<pjm@see_my_sig_for_address.com> wrote in message
news:peghg1dr05s67edsek37jla2fjl4otm61n@4ax.com...
> On Sun, 21 Aug 2005 10:46:35 -0700, "PrecisionMachinisT"
> <precisionmachinist@hotmail.com> wrote:
>
>
> See cow.
>
> See cow udders.
>
> Pull cow udders.
>
> Get milk.
>
> If cow only have one udder, get cream.
"I think I'll go wash up..."
>
>
> Click here every day to feed an animal that needs you today !!!
>
> http://www.theanimalrescuesite.com/
>
> Paul ( pjm @ pobox . com ) - remove spaces to email me
> 'Some days, it's just not worth chewing through the restraints.'
> 'With sufficient thrust, pigs fly just fine.'
> HVAC/R program for Palm PDA's
> Free demo now available online http://pmilligan.net/palm/
| |
| Joseph 2005-08-21, 7:21 pm |
|
"TURTLE" <turtle4aire@bellsouth.net> wrote in message
news:062Oe.43519$rp.25413@bignews1.bellsouth.net...
>
> "PrecisionMachinisT" <precisionmachinist@hotmail.com> wrote in message
> news:UfudnXEM3PQbO5veRVn-qA@scnresearch.com...
>
> This is Turtle.
>
> i see the example all the time with ice cub trays all the time. Fill a ice cube
> tray with water and let them freeze real good and then keep them in the freezer
> for 1 years. You will come back and find all the ice gone out of the ice cube
> tray. I call it freezer evaperation or called freezer burning the ice. This
> dehydration takes all the moisture out of food product and is called freezer
> burn.
Also it can be freeze dried...
Joseph
> TURTLE
>
>
| |
| pjm@see_my_sig_for_address.com 2005-08-21, 7:21 pm |
| On Sun, 21 Aug 2005 14:19:42 -0700, "Joseph" <jrpitzner@yahoo.com>
wrote:
>
><pjm@see_my_sig_for_address.com> wrote in message
>news:peghg1dr05s67edsek37jla2fjl4otm61n@4ax.com...
>
> "I think I'll go wash up..."
>
I guess that can wait for an udder day.
Shoulda wore gloves.
Click here every day to feed an animal that needs you today !!!
http://www.theanimalrescuesite.com/
Paul ( pjm @ pobox . com ) - remove spaces to email me
'Some days, it's just not worth chewing through the restraints.'
'With sufficient thrust, pigs fly just fine.'
HVAC/R program for Palm PDA's
Free demo now available online http://pmilligan.net/palm/
| |
| ~^Johnny^~ 2005-08-21, 7:21 pm |
| -----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
> I guess that can wait for an udder day.
>
> Shoulda wore gloves.
Now you are in for a real teat.
-----BEGIN PGP SIGNATURE-----
Version: PGP 7.1
iQA/AwUBQwj3mAIk7T39FC4ZEQIg+gCeOJleXpVn84fHEmoKKKx74AqePXoAoOL5
YiIqi2zXsbkKjEjvLeO8Cl7g
=zaPo
-----END PGP SIGNATURE-----
--
-john
wide-open at throttle dot info
| |
| PrecisionMachinisT 2005-08-21, 9:21 pm |
|
"~^Johnny^~" <nospam@gyrogearloose.com> wrote in message
news:qpthg118lv01ekjqal2k5n1te29f72g8r0@4ax.com...
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
>
> Now you are in for a real teat.
>
Nice tits at this site:
http://www.nice-tits.org/
--
SVL
| |
| nicksanspam@ece.villanova.edu 2005-08-22, 2:21 pm |
| <gfretwell@aol.com> wrote:
>Repeat after me, a gas at a given temperature (ambient air) is heat.
Air = heat.
Oxygen = heat.
Nitrogen = heat...
Learn something new every day around here.
Nick
| |
| gfretwell@aol.com 2005-08-22, 5:21 pm |
| On 22 Aug 2005 08:46:05 -0400, nicksanspam@ece.villanova.edu wrote:
>Air = heat.
>Oxygen = heat.
>Nitrogen = heat...
>
>Learn something new every day around here.
If that air, nitrogen and oxygen is anything but 0 degrees Kelvin it
has heat. That is why we have "AIR" conditionoing in the first place.
For the purposes of this silly argument, water in the system will
actually be touching the metal or in the oil, both excellent
conductors of ambient heat. If the water is trapped in the dessicants
of the dryer, who cares?, That should be in the trash by now and a new
dryer in the system. If you are not replacing your dryers you are
certainly a hack.
| |
| pjm@see_my_sig_for_address.com 2005-08-22, 5:21 pm |
| On Mon, 22 Aug 2005 16:01:53 -0400, gfretwell@aol.com wrote:
>On 22 Aug 2005 08:46:05 -0400, nicksanspam@ece.villanova.edu wrote:
>
At least they're not = 'coolth' :-)
Excuse me, I have to go get a breath of fresh heat now ....
[color=darkred]
>If that air, nitrogen and oxygen is anything but 0 degrees Kelvin it
>has heat. That is why we have "AIR" conditionoing in the first place.
>
>For the purposes of this silly argument, water in the system will
>actually be touching the metal or in the oil, both excellent
>conductors of ambient heat. If the water is trapped in the dessicants
>of the dryer, who cares?, That should be in the trash by now and a new
>dryer in the system. If you are not replacing your dryers you are
>certainly a hack.
Click here every day to feed an animal that needs you today !!!
http://www.theanimalrescuesite.com/
Paul ( pjm @ pobox . com ) - remove spaces to email me
'Some days, it's just not worth chewing through the restraints.'
'With sufficient thrust, pigs fly just fine.'
HVAC/R program for Palm PDA's
Free demo now available online http://pmilligan.net/palm/
| |
| nicksanspam@ece.villanova.edu 2005-08-22, 6:21 pm |
| <gfretwell@aol.com> wrote:
[color=darkred]
>
>If that air, nitrogen and oxygen is anything but 0 degrees Kelvin it
>has heat. That is why we have "AIR" conditionoing in the first place.
Oh, you meant it CONTAINS heat...
Nick
| |
|
| Thank You
Mr. Richard J Kinc
For explaining to some of these VUSIS
and I say to some because when arrogance
superseded the ignorance there are some people
that will not except truth or the facts.
It does not metter how had you may try
Sorry I am not that patient
Good Luck from Dido
"Travis Jordan" <no.one@no.net> wrote in message
news:PYpNe.24917$0_.17057@fe04.news.easynews.com...
> papaya wrote:
>
> Most manufacturers installation instructions say evacuate to 350
> microns, then insure that the vacuum holds for at least a minute after
> closing off the vacuum pump. Their instructions (and their warranty)
> are good enough for me.
>
>
| |
| rick1matthews 2005-08-25, 9:21 am |
| > Richard J Kinchwrote:
PrecisionMachinisT writes:
>
> A lot of people have been taught the pseudo-scientific myth that
"water
> boils in a vacuum" in some magic sense that it doesn't in the
> atmosphere. The truth is that water vaporizes in a vacuum or in the
> atmosphere the same way: *only* because you add heat. In the same
> sense, water doesn't boil at 212 deg F, it boils because you add
more
> heat after it is at 212 deg F.
>
Nothing pseudo-scientific about it. I have boiled water with
ice.
Here is how: take a glass flask with an indentation in the bottom, add
a little water. You may want to add boiling chips to make the effect
more gradual. Attach a cork with a rubber hose to the top to vent.
Put it on a bunsen burner and boil, just to get the steam to drive all
the air out. Remove heat and clamp the rubber hose. Let it cool.
Invert, add ice to the depression, and watch the cool water boil, not
with the addition of heat, but with the addition of ice. I have
boiled water down to 60 degrees F with this technique.
What is happening is that cooling the glass on top causes most of the
remaining steam to condense, establishing a decent vacuum. Lowering
the pressure over the water lowers the boiling point, so the water
now boils.
You have said repeatedly that one must add heat for sublimation to
occur. That is not true. Sublimation and evaporation both proceed
by the same mechanism. Pour water on the floor, and it will
evaporate without addition of heat, unless the relative humidity is
100%. Sublimation happens, too, just starting from the solid instead
of liquid phase of water.
What is happening microscopically is related to the the kinetic energy
of the molecules. Temperature is not heat, as you pointed out. But
they are related. Temperature is defined to be proportional to the
random translational kinetic energy per molecule of the material.
Heat transfer is equal to the change of the random translation
kinetic energy plus rotational and vibrational kinetic energy plus
changes in potential energy. So any substance above absolute zero
contains heat, and its molecules have a distribution of kinetic
energies.
When a molecule on the surface achieves an atypically large kinetic
energy from collisions with its neighbors, it reaches escape
velocity. If the substance is a liquid, we call it evaporation. If
it is a solid, we call it sublimation. There is always a reverse
process of capture from the atmosphere. But the process is usually
slower.
The temperature of the surface determines the escape rate. The
partial pressure of water in the surrounding atmosphere determines
the capture rate. In a perfect vacuum, the capture rate is zero, and
the net effect is evaporation or sublimation.
| |
| nicksanspam@ece.villanova.edu 2005-08-25, 10:21 am |
| rick1matthews <matthews@wfu-dot-edu.no-spam.invalid> wrote:
>Pour water on the floor, and it will evaporate without addition of heat...
It's more accurate to say that the heat required to evaporate the water
(about 1000 Btu/lb) comes from the surroundings, ie this evaporation
cools the floor, the air, and so on.
Nick
| |
|
|
"rick1matthews" <matthews@wfu-dot-edu.no-spam.invalid> wrote in
message news:wriPe.150214$576.90026@fe02.news.easynews.com...
> PrecisionMachinisT writes:
> "water
the[color=darkred]
>
> more
>
> Nothing pseudo-scientific about it. I have boiled water with
> ice.
>
> Here is how: take a glass flask with an indentation in the bottom,
add
> a little water. You may want to add boiling chips to make the effect
> more gradual. Attach a cork with a rubber hose to the top to vent.
>
> Put it on a bunsen burner and boil, just to get the steam to drive
all
> the air out. Remove heat and clamp the rubber hose. Let it cool.
>
> Invert, add ice to the depression, and watch the cool water boil,
not
> with the addition of heat, but with the addition of ice. I have
> boiled water down to 60 degrees F with this technique.
>
> What is happening is that cooling the glass on top causes most of
the
> remaining steam to condense, establishing a decent vacuum. Lowering
> the pressure over the water lowers the boiling point, so the water
> now boils.
Julius Sumner Miller would be proud : )
>
> You have said repeatedly that one must add heat for sublimation to
> occur. That is not true. Sublimation and evaporation both proceed
> by the same mechanism. Pour water on the floor, and it will
> evaporate without addition of heat, unless the relative humidity is
> 100%. Sublimation happens, too, just starting from the solid
instead
> of liquid phase of water.
>
> What is happening microscopically is related to the the kinetic
energy
> of the molecules. Temperature is not heat, as you pointed out. But
> they are related. Temperature is defined to be proportional to the
> random translational kinetic energy per molecule of the material.
> Heat transfer is equal to the change of the random translation
> kinetic energy plus rotational and vibrational kinetic energy plus
> changes in potential energy. So any substance above absolute zero
> contains heat, and its molecules have a distribution of kinetic
> energies.
>
> When a molecule on the surface achieves an atypically large kinetic
> energy from collisions with its neighbors, it reaches escape
> velocity. If the substance is a liquid, we call it evaporation. If
> it is a solid, we call it sublimation. There is always a reverse
> process of capture from the atmosphere. But the process is usually
> slower.
>
> The temperature of the surface determines the escape rate. The
> partial pressure of water in the surrounding atmosphere determines
> the capture rate. In a perfect vacuum, the capture rate is zero,
and
> the net effect is evaporation or sublimation.
>
| |
| Rick Matthews 2005-08-27, 8:22 pm |
| nicksanspam@ece.villanova.edu wrote on 8/25/2005 8:37 AM:
> rick1matthews <matthews@wfu-dot-edu.no-spam.invalid> wrote:
>
>
>
>
> It's more accurate to say that the heat required to evaporate the water
> (about 1000 Btu/lb) comes from the surroundings, ie this evaporation
> cools the floor, the air, and so on.
>
Some of the heat comes from the surroundings in
this example. Some comes from within the water itself.
Key to this discussion is that no external source of
heat is needed to evaporate water.
Were a 70 degree F drop of water suspended (perhaps in a weightless
environment) in a hard vacuum, which in turn is completely
surrounded by shiny surfaces cooled to 100 milliKelvin, the drop
would still evaporate.
So where did the heat come to evaporate it?
Statements were made earlier that water only boils when
heat is added and that water only evaporates when heat
is added. Neither statement is true.
Water evaporates whenever the partial pressure of water
in the surrounding atmosphere is so small that the
capture of the water molecules from the air is less
than the escape of water molecules from the surface
of the water. The rate of escape is determined by
the water temperature. The rate of capture is determined
by the partial pressure of water. The water temperature
at which the two are in equilibrium is called the dew point.
If the water is cooler than the dew point, you get net
condensation. If the water is warmer than this dew point,
you get net evaporation.
When air pressure is very low, the partial pressure
of water can only be lower. Therefore the dew point must
be quite low, so that 72 degree F water (or 35 degree F
water, for that matter), is warmer that its dew point.
Water molecules are always escaping, and there are few
water molecules in the environment to balance the process.
Hence, the water evaporates.
The cooler it is, the slower it evaporates, but it does
still evaporate. In a perfect vacuum, even a 1 Kelvin ice
cube would eventually sublime way, though not in billion
years.
--
Rick Matthews matthews@wfu.edu
| |
| Richard J Kinch 2005-08-29, 9:21 pm |
| Rick Matthews writes:
> Statements were made earlier that water only boils when
> heat is added and that water only evaporates when heat
> is added. Neither statement is true.
It is true in the sense that the heat content of the water itself can
only evaporate a small portion of it. If you squirted warm water out of
the Space Shuttle in orbit, some would flash to vapor but most of it would
just wind up floating around frozen. The point is simply that vacuum
itself does not evaporate water, it is heat, contrary to the popular
notion.
| |
|
| True, most of the water will freeze before evaporating. But
you also said:
> It *will not* sublime at all if there is no heat added, even in a perfect vacuum.
which is not true.
The ice will sublime in a perfect vacuum if it is above absolute zero,
as long as there is any ice left.
Change "at all" to "quickly" and I will agree with you.
Rick
| |
| gfretwell@aol.com 2005-08-30, 1:21 am |
| On Mon, 29 Aug 2005 18:46:23 -0500, Richard J Kinch
<kinch@truetex.com> wrote:
> If you squirted warm water out of
>the Space Shuttle in orbit, some would flash to vapor but most of it would
>just wind up floating around frozen
The thing you are missing is gravity. Ice is not going to "float
around" in that pipe. It will lay on the pipe (compressor, valves etc)
and heat from the ambient air on the other side of the pipe will
evaporate the water.
| |
| Richard J Kinch 2005-08-30, 5:21 am |
| Rick writes:
> The ice will sublime in a perfect vacuum if it is above absolute zero,
> as long as there is any ice left.
If it is above absolute zero, then it must have had some heat added.
| |
| Richard J Kinch 2005-08-30, 6:21 am |
| > The thing you are missing is gravity. Ice is not going to "float
> around" in that pipe. It will lay on the pipe (compressor, valves etc)
> and heat from the ambient air on the other side of the pipe will
> evaporate the water.
Some of it will gain heat by this process, although much more slowly
than one might expect or hope. Remember it takes a huge amount of heat
transfer to vaporize water, and the vacuum is an excellent insulator.
Parts of a
glob of water in contact with the system will freeze and then tend to
sublimate a thin layer of vapor to separate themselves from the heat
source, instead of staying in intimate contact. And remember this
doesn't work at all for water entrained in or bound to something else.
Another practical problem in a AC system is that the water may trapped
on the other side of 50 feet of of 3/8 inch tubing from the vacuum
source, such as if the service connection is at the compressor on a
split system with the water stuck up in the evaporator. The back
pressure of a long thin line will spoil the vacuum on the other end.
My point is simply to correct the common misconception among AC techs
that if they pull a good vacuum on a system that it is guaranteed to be
dry, because they believe "water boils in a vacuum" from seeing a high
school science demonstration. The purpose of vacuuming an AC system is
to remove non-condensibles, not to clean out contaminants like water.
| |
|
| That does not follow.
Rick
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