In James Lerch's system he uses an adjustable valve to "tune" the
amount of cooling derived from an air conditioning compressor to cool
his cold trap... I have a similar cold trap (3 actually) that I have
not set up yet. They came with compressors, expansion chambers and
capillary tubes.

Should I go ahead and try using the capillary tubes or change over to
an adjustable valve? I would have to re-weld, silver solder the
capillary tubes back into the chambers to get them working.

Does the tubing aperature actually have to be changed if the
compressed liquid type is changed? I'm not sure what the original
refrigerant was but the system is fairly ancient. Most likely I'd
have to change refrigerent types to a newer approved refrigerant.

Anybody out there have any ideas on what would be the best way to
proceed?

Looks like I might need to start a "compressed gasses" group...

Ken Hunter

开云体育

Hi James,

Thanks for the informative post on the Capillary tube usage.

I don't know much about those things but I'd have to guess that the
capillary tubes I have are about 6-8 feet long (in a 3 inch dia
coil), maybe 1/16th inch OD and have a hole so tiny that I can't blow
air through them. I can take some photo's later but doubt that you'll
be able to see anything.

The 3 compressor units came on a frame with my 3 diffusion pumps,
valves etc. and 2 of thecapillary tubes were broken off at the point
where they were (looks like) soldered into the expansion chamber. I
haven't taken them apart to see what's inside but I imagine just a
couple inches of the capillary tube is sticking into the chamber.

Thought I could re-solder (maybe have to silver solder) the Capillary
tube back into the chamber and give it a go to see what happens. I
think I have a photo of the valves that also shows the compressors...

I'll need to find a set of A/C gauges to give it a try. Interesting
that you said just to give it a shot of freon... I gather the idea is
to get the maximum pressure differential across the chamber while
still delivering a compressed liquid to the chamber to be expanded.

I'll try to get some measurements of the Capillary tubing and some
photo's this week if it get's warm enough to get outside to the barn.

There sure is a lot to learn.

Ken Hunter

On Sun, 2003-01-26 at 08:32, Ken Hunter wrote:

Hi James,

Thanks for the informative post on the Capillary tube usage.

I don't know much about those things but I'd have to guess that the
capillary tubes I have are about 6-8 feet long (in a 3 inch dia
coil), maybe 1/16th inch OD and have a hole so tiny that I can't blow
air through them. I can take some photo's later but doubt that you'll
be able to see anything.

The 3 compressor units came on a frame with my 3 diffusion pumps,
valves etc. and 2 of thecapillary tubes were broken off at the point
where they were (looks like) soldered into the expansion chamber. I
haven't taken them apart to see what's inside but I imagine just a
couple inches of the capillary tube is sticking into the chamber.

Thought I could re-solder (maybe have to silver solder) the Capillary
tube back into the chamber and give it a go to see what happens. I
think I have a photo of the valves that also shows the compressors...

Yes - it is necessary to silver solder. If you just use a tin lead (or
whatever the newer version is) you run a severe risk of failure. Silver
solder done well has a tensile that is higher than your base material
where regular tin lead (I think the new version is zinc tin???) is
considerably weaker (about 5000# tensile if my information is correct
(it was for 37% Sn solder)).

I'll need to find a set of A/C gauges to give it a try. Interesting
that you said just to give it a shot of freon... I gather the idea is
to get the maximum pressure differential across the chamber while
still delivering a compressed liquid to the chamber to be expanded.

I'll try to get some measurements of the Capillary tubing and some
photo's this week if it get's warm enough to get outside to the barn.

There sure is a lot to learn.

Maybe I should introduce myself. I am a machinist with a fair amount of
welding experience that also likes to tinker. Astronomy has been
something that I have wanted to get into for a long time so I am
gathering information and we will see from there.

Has anyone here silvered a mirror and then coated it?

Just wondering how something like that would work out.

Darald

Hi Darald,

James is the ONE to ask about silvering... He has done quite a few
mirrors that way and I believe he's made a few attempts at coating
them to prevent tarnishing. I'd bet that he can give you all the info
you need to Silver then give you his reasons for Aluminizing too...

Check out his web page. The URL for his web site is in the LINKS
section

<------- over there

Ken Hunter

--- In VacuumX@..., Darald Bantel <dbantel@t...> wrote:

On Sun, 2003-01-26 at 08:32, Ken Hunter wrote:

Hi James,

Thanks for the informative post on the Capillary tube usage.

I don't know much about those things but I'd have to guess that

the

capillary tubes I have are about 6-8 feet long (in a 3 inch dia
coil), maybe 1/16th inch OD and have a hole so tiny that I can't

blow

air through them. I can take some photo's later but doubt that

you'll

be able to see anything.

The 3 compressor units came on a frame with my 3 diffusion pumps,
valves etc. and 2 of thecapillary tubes were broken off at the

point

where they were (looks like) soldered into the expansion chamber.

I

haven't taken them apart to see what's inside but I imagine just

a

couple inches of the capillary tube is sticking into the chamber.

Thought I could re-solder (maybe have to silver solder) the

Capillary

tube back into the chamber and give it a go to see what happens.

I

think I have a photo of the valves that also shows the

compressors...

Yes - it is necessary to silver solder. If you just use a tin lead

(or

whatever the newer version is) you run a severe risk of failure.

Silver

solder done well has a tensile that is higher than your base

material

where regular tin lead (I think the new version is zinc tin???) is
considerably weaker (about 5000# tensile if my information is

correct

(it was for 37% Sn solder)).

I'll need to find a set of A/C gauges to give it a try.

Interesting

that you said just to give it a shot of freon... I gather the

idea is

to get the maximum pressure differential across the chamber while
still delivering a compressed liquid to the chamber to be

expanded.

I'll try to get some measurements of the Capillary tubing and

some

photo's this week if it get's warm enough to get outside to the

barn.

There sure is a lot to learn.

Maybe I should introduce myself. I am a machinist with a fair

amount of

welding experience that also likes to tinker. Astronomy has been
something that I have wanted to get into for a long time so I am
gathering information and we will see from there.

Has anyone here silvered a mirror and then coated it?

Just wondering how something like that would work out.

Darald

Hi Ken,
a bit late but this site may have what you are looking for
Its also a great set of instructions on how to build your own cooler using old fridge pumps.
well worth a look.

Charles

Charles...

Thanks for that link...

A lot of good information on the refrigerants but not much mention
of how to adjust or figure the capillary size.

I've got it bookmarked for later reference.

Ken Hunter

--- In VacuumX@..., Charles Mitchard
<charlesmitchard@i...> wrote:

Hi Ken,
a bit late but this site may have what you are looking for
Its also a great set of instructions on how to build your own

cooler using

old fridge pumps.
well worth a look.

Charles

Does the tubing aperature actually have to be changed if the
compressed liquid type is changed? I'm not sure what the original
refrigerant was but the system is fairly ancient. Most likely I'd
have to change refrigerent types to a newer approved refrigerant.

Anybody out there have any ideas on what would be the best way to
proceed?

Looks like I might need to start a "compressed gasses" group...

Ken Hunter

---
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--- In VacuumX@..., Charles Mitchard
<charlesmitchard@i...> wrote:

Hi Ken,
a bit late but this site may have what you are looking for
Its also a great set of instructions on how to build your own

cooler using

old fridge pumps.
well worth a look.

Hey if Ken starts a "Compressed Gas" list - let me know!

One can acquire a EPA 609 license for $15 + an online test. The 609
is required to purchase most anything other than R134. One place is


The overclockers site seems fairly accurate, except for methane.
Methane won't liquify at any pressure whatsoever at temperatures
anywhere close to ambient. Critical temperature (which is -82C) is
too low. Same for Argon and certain other gasses listed on
overclockers.

Large over the road vehicles configured for natural gas often contain
a cryogenic plant in order to keep their methane fuel liquid (and
therefore reasonably dense). Mostly local semi tractors in
California.

The following provides useful information about many interesting
substances:

?
Select your gas, and the site will regurgitate the facts!

A site containing an interesting critical point experiment:


-Bill