--- In VacuumX@..., "nano_tronics" <nortronics@s...>
wrote:

--- In VacuumX@..., gjnelson@a... wrote:

Were you thinking of this?



It is a sorption pump and is useful for small things.

I think it could be used very well for testing gauges but not for

pumping down a

chamber of a significant size

some time ago on the net i saw a site witch talked about plans

to

make

OK found it :)

just read the article

your own VD pump out of ordinary threaded steel or copper pipes

and

fittings and performed quite good especialy from out of standard
plumbing stuff, i cant remember what magazine it was all i

know

that

it was a monthly science mag like american scientist or amateur
scientist or something like that

no no i was talking about a real home made vapor diffusion pump

damm

i cant remember in witch magazine and what article it was :( ill

try

to trace that info

--- In VacuumX@..., gjnelson@a... wrote:

Were you thinking of this?



It is a sorption pump and is useful for small things.

I think it could be used very well for testing gauges but not for

pumping down a

chamber of a significant size

some time ago on the net i saw a site witch talked about plans to

make

your own VD pump out of ordinary threaded steel or copper pipes

and

fittings and performed quite good especialy from out of standard
plumbing stuff, i cant remember what magazine it was all i know

that

it was a monthly science mag like american scientist or amateur
scientist or something like that

no no i was talking about a real home made vapor diffusion pump damm
i cant remember in witch magazine and what article it was :( ill try
to trace that info

Were you thinking of this?



It is a sorption pump and is useful for small things.

I think it could be used very well for testing gauges but not for pumping down a
chamber of a significant size

--- In VacuumX@..., RON WHITE <ron_white@s...> wrote:

Time is a real problem right now I have way to many projects going

on but I think I can get the info shortly. the bottom spinning sets
flat to the bottom and if memory is correct there are small notches 3
or 4 to allow the oil under it. I think the oil level is what
generates the pressure difference to force the vapor to the top. I'll
get sketches / photos

Ron white

Charles Mitchard <charlesmitchard@i...> wrote:
Hi Ron,
I would love some dimensions if you have the time.
From what I can see of the glass design it should be simple to

build in

aluminium or stainless.
Do the chimneys actually sit in the oil or do they sit just above

the oil?

Thats the sort of questions I have at the moment.
I would use a freezer coil and jacket surrounding the parts

requiring

cooling to experiment with.
Charles

At 04:04 AM 8/11/03 +0000, you wrote:

Geoff
Welcome, the glass pump looks real sharp It looks like a lot of

work

to put it together.
E-bay seems to be where most of us get used stuff.
The workings of most of these pumps seem to be simple so I don't

know

that you would need an engineered design, rather just scale some of
the existing sketches and go from there. I would be glad to measure
up one or both of mine but they are very old and I don't know if

the

design is obsolete. I have a CVC 6"(I think!)and a varian 3" If

you

have access to someone with a wood lathe and metal spinning

experence

it may be easer to make one from some soft (1100 )aluminum and

pipe.

The glass one does looks nice. How do you cool it?

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some time ago on the net i saw a site witch talked about plans to
make your own VD pump out of ordinary threaded steel or copper pipes
and fittings and performed quite good especialy from out of standard
plumbing stuff, i cant remember what magazine it was all i know that
it was a monthly science mag like american scientist or amateur
scientist or something like that

开云体育

Hi Ron,
I would love some dimensions if you have the time.
From what I can see of the glass design it should be simple to build in aluminium or stainless.
Do the chimneys actually sit in the oil or do they sit just above the oil? Thats the sort of questions I have at the moment.
I would use a freezer coil and jacket surrounding the parts requiring cooling to experiment with.
Charles

Geoff
Welcome, the glass pump looks real sharp It looks like a lot of work
to put it together.
E-bay seems to be where most of us get used stuff.
The workings of most of these pumps seem to be simple so I don't know
that you would need an engineered design, rather just scale some of
the existing sketches and go from there. I would be glad to measure
up one or both of mine but they are very old and I don't know if the
design is obsolete. I have a CVC 6"(I think!)and a varian 3" If you
have access to someone with a wood lathe and metal spinning experence
it may be easer to make one from some soft (1100 )aluminum and pipe.
The glass one does looks nice. How do you cool it?

We all tend to talk to little a bit of chatter would be most
welcome.

Ron White

-

Hi

I am new here, James Lerch told me about you guys. I have just finished reading the
archives. Interesting and seems like a good resource.

I am busy trying to find parts for a vacuum system for ATM aluminium coating. South
Africa seems to be a little poor on the second hand diffusion pump side. I have
however found a local glass blower who can make a diffusion pump. The inlet would
end up being about one inch. Does anyone have any experience to share.

Please check out the the following

I saw in the archives that someone was looking for design parameters for a pump. If
someone at an academic institution can access this then we may have a source for the
design criteria. I am thinking particularly of the people who live in out of the way places
like South Africa.

I am still asking around for an ultra centrifuge as it may be a little more accessible than
other redundant equipment.

Any other ideas where I may get some old equipment.

Kind regards and nice to meet you folks.

Geoff

Please be patient with me I do tend to talk a bit much

On Tuesday, November 4, 2003, at 09:48 AM, arcstarter wrote:

OK, I just bought a used diffusion pump.
Inlet is about 3 inches.
Outlet is about 1 inch.
Height is about 12 inches.
Water cooled with normally closed thermostat device on the water
jacket.

Since I don't have a spec sheet, I am at a bit of a loss as to how
to proceed. For instance, how do I determine what volume of oil to
use? The label indicates that this is an Alcatel model 6063 (which
I have looked for on the 'net but not been able to find specs on).
There are fields on the label for power, liters/minute etc but the
numbers were not inserted!

Have you tried calling up Alcatel?

The heater is also a bit of a mystery. There are apparently two
heating elements, currently wired in series but with all three leads
coming out of the can. Element one (which is physically located on
the outside edge of the heating base) measures 134 ohms. Element
two (which is located in the center of the base) measures 248 ohms,
but has heavier gauge wires than the outer heater.

Differential heating of diffusion pumps is mentioned in the literature,
to achieve a temperature gradient across the base of the stack, from
inside to outside. This is probably in support of that, although
without the technical docs, there's probably no way to tell how to
set yours up correctly.

OK, I just bought a used diffusion pump.
Inlet is about 3 inches.
Outlet is about 1 inch.
Height is about 12 inches.
Water cooled with normally closed thermostat device on the water
jacket.

Since I don't have a spec sheet, I am at a bit of a loss as to how
to proceed. For instance, how do I determine what volume of oil to
use? The label indicates that this is an Alcatel model 6063 (which
I have looked for on the 'net but not been able to find specs on).
There are fields on the label for power, liters/minute etc but the
numbers were not inserted!

The heater is also a bit of a mystery. There are apparently two
heating elements, currently wired in series but with all three leads
coming out of the can. Element one (which is physically located on
the outside edge of the heating base) measures 134 ohms. Element
two (which is located in the center of the base) measures 248 ohms,
but has heavier gauge wires than the outer heater.

Rumor has it that this is wired for 220 volts, but this is not
necessarily accurate. There is a 4th wire which is tied to the pump
chassic ground and is not shared with the heaters. If 220 volts
were applied to these two elements in series - power would be about
126 watts. Is this wattage in the ballpark for a water-cooled unit?

The other way to wire it would be to apply 220 across the elements
in parallel, whcih would produce ~560 watts total dissipation -
which seems perhaps a bit more reasonable for the water-cooled
jacket?

Can anyone advise me about typical wattages for a unit of these
dimensions? Does anyone have information on a dual-coil heating
element for these sorts of things?

Thanks in advance!
-Bill

--- In VacuumX@..., Gomez <gomez@o...> wrote:

On Thursday, October 30, 2003, at 05:13 AM, nano_tronics wrote:

ok now i understand , i tought that to have an UVH in a closed

seal

container it was needed to be pumped as long as it need to be
substained because of constant outgasing of container material

Obviously not, (if everything is done right) since things like

high

vacuum
capacitors and other ultra high vacuum devices work fine for

decades

without
so much as a getter. The tricks are getting everything clean

enough,

using
the right materials, bake-out, and so on.

i understand that the getter play a big roles in stabilyzing the
vacuum
if every proceding step is taken care of for reaching the UVH

barrier

and torr can be translate to hg/mm

Yes. 1000 Torr = 1000 mm/Hg @ 0C. 760 Torr = 1 atmosphere

(standard)

i ask this question because it
gets confusing when looking for spec for VD pumps many of them

are in

mbar some in pascal and other in torr i prefer to work with torr

too

it is less confusing

There are many handy software utilities for most operating

systems

which
will convert any unit of measure into any other (within a

measurement

regime,
such as pressure). In MacOS, I use a tool called

simply, "Convert" -

very
handy, and worth every bit of the $15 shareware fee.

thank you so much for answering my question now i know what can be
done and what cant, it is much clearer for me now :)

and dont worry when ill be able to get all my vacuum pump stuff ill
let you know for sure :)

Now I have a handle on how diffusion pumps work would anyone be willing to post a sketch/drawing with dimensions of all the various bits.
Such as how the various chimneys and baffles fit, their angles plus the sizes of any holes the jet stream of hot vapor shoots out.
I cannot find a suitable source here in Oz (thats cheap to everyone else) so would like to have a go at building something.

For an excellent converter try here

Many thanks
Charles

Many times I have used old refrigerators or deep freezers as cooling plants for a variety of tasks.
Find a throwaway that still works but is rusty (no value) remove all the cooling equipment in one piece. (I often use a thin chisel to cut the tin)
If you have a friend who is a refrigeration mechanic then cutting and re-gassing is easier. (venting to atmosphere???)
Wrap the cooler plate around what you want to cool.
Seal in place to make a container, (Ive used epoxy and silicone, they both work) insulate the outside, fill with glycol and switch on.
If you can find a fridge with cooler pipes instead of a plate its even easier.
The radiator can be folded inside a large dia pipe with a fan to improve the temp differential and reduce footprint.

Questions:-
Would this produce a sufficient temp drop for the diffusion pump?
What about using it for cold traps?

Does anyone know if it is possible to over-cool a water-cooled
diffusion pump?

If this answer is yes then a thermostat would solve it.

Charles

On Thursday, October 30, 2003, at 09:05 AM, arcstarter wrote:

Comments:
--- In VacuumX@..., "nano_tronics" <nortronics@s...>
wrote:

here are my questions

1) how much ultimate vacuum i can achive with a diffusion pump

setup

bellow

a) without a cold trap ( and oil backstreaming problem that go's
with it )

b) with a cold trap

c) a cheap an easy way to replace the LN2 coolant for the cold

trap

Here's a hair-brained idea. Since once a reasonable vacuum level is
achieved (1 micron or whatever it takes to start the diffusion
pump) - the actual mass flow through the cold trap is very low.
Therefore would it be possible to use some of the thermo-electric
cooling elements (Peltier devices) to cool the baffle plates? Total
heat flow will be low (perhaps mostly radiative), and the Peltiers
can be arranged in series to add temperature drops etc.

Temperature differential is created by moving heat. The greater the
differential, the more heat you have to move. While the heat load
entering the cold trap from the inside of the vacuum system may be
low, there is lots of other heat from the room and the material of
the trap itself, and its physical connections to the rest of the
system, which are constantly trying to warm it up. That actually
represents the lion's share of the heat you need to remove.

Now then, the amount of heat transported by each Peltier array is
proportional to the current through it. Furthermore, each Peltier
array has a maximum temperature differential it will sustain at its
maximum electrical ratings. For greater differentials, you have to
put several arrays in series. This is how very cold focal plane
array temperatures are achieved on some chilled CCD cameras for low
light photography (to reduce the inherent thermal noise of the array)

So, to get to LN2 or at least dry ice temperatures, you are going
to have to have 1) a lot of Peltier arrays in a series-parallel
arrangement and 2) an insane amount of power.

I had the chance to speak face to face with Don Mattox at the Indy
coating show yesterday, and I asked him about Peltier cold traps.
As far as he knows it hasn't been tried.

They are not very efficient. Moving fluid refrigeration is more
efficient. Their sole advantage is light weight and low cost.
Note that the portable coolers which use them have either large or
cigarette lighter cords to run off of a car's power. They also have
thicker insulation than regular ice chests. The owner's manuals
recommend that you not attempt to chill down the contents of the
cooler with the cooler alone, but rather that you put already-cold
foods into it and use the cooler only to help maintain a low
temperature.

In short, it could certainly be done, but at a very high cost
compared to the alternatives.

2) the pros an cons of air cooled VS liquid cooled diffusion pump

3) on a liquid cooled VD pump can a radiator with a fan and a
circulator pump be used instead of running faucette water

I was planning on doing exactly this. Can get a condensation pump
(intended to be used with a high efficiency fgurnace to remove flue
condensation) for about $50 or less - right off the shelf at
Grainger's etc. I think this would do the job. www.meci.com used to
have heater cores out of cars - which could be used for the radiator.

I believe that the efficiency of the diff. pump is related to how well the
walls are cooled. Warm water won't work as well as cool water, if the VD
is designed to use water cooling. A heat exchanger without refrigeration
will only lower your loop temp down to slightly above ambient, at best.

Another arrangement might be to use your cold trap AC system to
assist in cooling the closed-loop water used to chill a water-cooled
diffusion pump... This might allow you to use the fan and condenser
out of the AC to not only cool the cold trap but cool the diffusion
pump.

That's an interesting idea.

Does anyone know if it is possible to over-cool a water-cooled
diffusion pump?

That's a very good question! And one we should answer before anyone goes
to all the effort to try this.

I have a line on a used evaporating station - no vac pumps but with
misc vac valves and a 18 inch diam x 30 tall bell jar. Filament
transformer is included. They want $500 which I think is a good
deal.

Sweet! It's possible to do better, but that still seems reasonable.

Also I took apart a commercial $0.50 quartz crystal the other day -
one of those HC-49 type package styles such as this one:

I used a coarse file to remove the top of the can. Inside the can
I found a quartz slab with metallized sides connected to the
leadouts. I am considering using these as film thickness monitors
in the evaporator. The price is right!

Let us know how that works for you - I'm very curious about that myself.

On Thursday, October 30, 2003, at 05:13 AM, nano_tronics wrote:

ok now i understand , i tought that to have an UVH in a closed seal
container it was needed to be pumped as long as it need to be
substained because of constant outgasing of container material

Obviously not, (if everything is done right) since things like high vacuum
capacitors and other ultra high vacuum devices work fine for decades without
so much as a getter. The tricks are getting everything clean enough, using
the right materials, bake-out, and so on.

i understand that the getter play a big roles in stabilyzing the vacuum
if every proceding step is taken care of for reaching the UVH barrier

and torr can be translate to hg/mm

Yes. 1000 Torr = 1000 mm/Hg @ 0C. 760 Torr = 1 atmosphere (standard)

i ask this question because it
gets confusing when looking for spec for VD pumps many of them are in
mbar some in pascal and other in torr i prefer to work with torr too
it is less confusing

There are many handy software utilities for most operating systems which
will convert any unit of measure into any other (within a measurement regime,
such as pressure). In MacOS, I use a tool called simply, "Convert" - very
handy, and worth every bit of the $15 shareware fee.

Comments:
--- In VacuumX@..., "nano_tronics" <nortronics@s...>
wrote:

here are my questions

1) how much ultimate vacuum i can achive with a diffusion pump

setup

bellow

a) without a cold trap ( and oil backstreaming problem that go's
with it )

b) with a cold trap

c) a cheap an easy way to replace the LN2 coolant for the cold

trap

Here's a hair-brained idea. Since once a reasonable vacuum level is
achieved (1 micron or whatever it takes to start the diffusion
pump) - the actual mass flow through the cold trap is very low.
Therefore would it be possible to use some of the thermo-electric
cooling elements (Peltier devices) to cool the baffle plates? Total
heat flow will be low (perhaps mostly radiative), and the Peltiers
can be arranged in series to add temperature drops etc.

I had the chance to speak face to face with Don Mattox at the Indy
coating show yesterday, and I asked him about Peltier cold traps.
As far as he knows it hasn't been tried.

2) the pros an cons of air cooled VS liquid cooled diffusion pump

3) on a liquid cooled VD pump can a radiator with a fan and a
circulator pump be used instead of running faucette water

I was planning on doing exactly this. Can get a condensation pump
(intended to be used with a high efficiency fgurnace to remove flue
condensation) for about $50 or less - right off the shelf at
Grainger's etc. I think this would do the job. www.meci.com used to
have heater cores out of cars - which could be used for the radiator.

Another arrangement might be to use your cold trap AC system to
assist in cooling the closed-loop water used to chill a water-cooled
diffusion pump... This might allow you to use the fan and condenser
out of the AC to not only cool the cold trap but cool the diffusion
pump.

Lets see - seem to recall that a small 'window-banger' air
conditioner would pull about 5100 BTU/hr of heat out of the
evaporator. 5100 BTU/hr = 1400 watts or so. So a small AC would
(with a proper heat exchanger) cool a diffusion pump ~1400 watts
(which is a pretty big pump IMO).

Units conversions at:


Does anyone know if it is possible to over-cool a water-cooled
diffusion pump?

I have a line on a used evaporating station - no vac pumps but with
misc vac valves and a 18 inch diam x 30 tall bell jar. Filament
transformer is included. They want $500 which I think is a good
deal.

Also I took apart a commercial $0.50 quartz crystal the other day -
one of those HC-49 type package styles such as this one:

I used a coarse file to remove the top of the can. Inside the can
I found a quartz slab with metallized sides connected to the
leadouts. I am considering using these as film thickness monitors
in the evaporator. The price is right!

Anyone ever tried rolling their own film monitor?

-Bill