JG
Joe Gwinn
Thu, Dec 24, 2009 7:49 PM
A dodge occurs to me - a homebrew heat pipe:
http://en.wikipedia.org/wiki/Heat_pipe.
Make the cold plate of copper, to which is soldered a meandering
piece of copper tubing, which tubing is also soldered to a copper
radiator plate that is above the coldplate, forming a closed loop
with a fill tube attached by a T. Braze all tubing connections, as
for freon refrigeration systems. (Soft solder is too porous to work
for the joints, but is OK for attaching tubes to plates.)
Insulate the two tubes running between coldplate and radiator plate
from one another.
Put enough working fluid into the system to fill the tubing that is
soldered to the coldplate, but no more. Warm the system up so the
vapor drives all the air out, pinch the fill tube off and fold it
back, and braze the end shut. (It's not critical to get absolutely
all the air out.)
Making the radiator plate be above the coldplate (the boiler)
implements what amounts to an oldtime two-pipe water vapor heating
plant. Vapor goes up one pipe, condensed fluid returns via the
other. I lived in a house with such a system. The difference
between a vapor plant and a steam plant is pressure: the vapor plant
runs below atmospheric pressure, while the steam plant runs at or
slightly above.
Make sure that things are arranged so the returning fluid does not
pool anywhere but in the coldplate, or the heat pipe will bang like
an old steam heating system.
There is a brazing filler metal intended for copper-to-copper joints
that is widely used for freon systems:
http://www.uniweld.com/catalog/alloys/silver_brazing_alloys/phos_copper.htm.
The zero silver phos stuff is adequate, cheap and widely available.
While copper-to-copper needs no flux, copper-to-brass does, so also
get the flux. Plumbing supply houses and welding equipment stores
are likely sources. You will also need a torch or pair of torches
able to raise the tubing joints to an orange heat in a reasonable
length of time.
Depending on the chosen working fluid, the cold plate temperature
will not rise above the boiling point of the fluid unless the system
is too small (in radiator heat removal capacity) to easily handle the
10 or 20 thermal watts that are passing through.
What fluid to use? Anything common and thermally stable that does
not attack copper. Alcohol (methyl or ethyl) and water are common
choices, as are the various freons. I bet acetone would also work.
Anyway, one controls the coldplate temperature by a combination of
choice of working fluid and internal pressure.
I have seen commercially made heat pipes for cooling Intel CPUs
advertised, but I don't know that these units can be adapted.
Anyway, a heat pipe system will stabilize the coldplate temperature
fairly accurately despite variations in thermal load, has no moving
or electrical parts, and may be sufficient by itself. If not
sufficient, it can be used as the outer stage in a two-stage ovening
scheme.
Joe Gwinn
A dodge occurs to me - a homebrew heat pipe:
<http://en.wikipedia.org/wiki/Heat_pipe>.
Make the cold plate of copper, to which is soldered a meandering
piece of copper tubing, which tubing is also soldered to a copper
radiator plate that is above the coldplate, forming a closed loop
with a fill tube attached by a T. Braze all tubing connections, as
for freon refrigeration systems. (Soft solder is too porous to work
for the joints, but is OK for attaching tubes to plates.)
Insulate the two tubes running between coldplate and radiator plate
from one another.
Put enough working fluid into the system to fill the tubing that is
soldered to the coldplate, but no more. Warm the system up so the
vapor drives all the air out, pinch the fill tube off and fold it
back, and braze the end shut. (It's not critical to get absolutely
all the air out.)
Making the radiator plate be above the coldplate (the boiler)
implements what amounts to an oldtime two-pipe water vapor heating
plant. Vapor goes up one pipe, condensed fluid returns via the
other. I lived in a house with such a system. The difference
between a vapor plant and a steam plant is pressure: the vapor plant
runs below atmospheric pressure, while the steam plant runs at or
slightly above.
Make sure that things are arranged so the returning fluid does not
pool anywhere but in the coldplate, or the heat pipe will bang like
an old steam heating system.
There is a brazing filler metal intended for copper-to-copper joints
that is widely used for freon systems:
<http://www.uniweld.com/catalog/alloys/silver_brazing_alloys/phos_copper.htm>.
The zero silver phos stuff is adequate, cheap and widely available.
While copper-to-copper needs no flux, copper-to-brass does, so also
get the flux. Plumbing supply houses and welding equipment stores
are likely sources. You will also need a torch or pair of torches
able to raise the tubing joints to an orange heat in a reasonable
length of time.
Depending on the chosen working fluid, the cold plate temperature
will not rise above the boiling point of the fluid unless the system
is too small (in radiator heat removal capacity) to easily handle the
10 or 20 thermal watts that are passing through.
What fluid to use? Anything common and thermally stable that does
not attack copper. Alcohol (methyl or ethyl) and water are common
choices, as are the various freons. I bet acetone would also work.
Anyway, one controls the coldplate temperature by a combination of
choice of working fluid and internal pressure.
I have seen commercially made heat pipes for cooling Intel CPUs
advertised, but I don't know that these units can be adapted.
Anyway, a heat pipe system will stabilize the coldplate temperature
fairly accurately despite variations in thermal load, has no moving
or electrical parts, and may be sufficient by itself. If not
sufficient, it can be used as the outer stage in a two-stage ovening
scheme.
Joe Gwinn
DL
Don Latham
Thu, Dec 24, 2009 8:27 PM
Are we getting close to a Stirling engine running as a frig?
Don
Joe Gwinn
A dodge occurs to me - a homebrew heat pipe:
http://en.wikipedia.org/wiki/Heat_pipe.
Make the cold plate of copper, to which is soldered a meandering
piece of copper tubing, which tubing is also soldered to a copper
radiator plate that is above the coldplate, forming a closed loop
with a fill tube attached by a T. Braze all tubing connections, as
for freon refrigeration systems. (Soft solder is too porous to work
for the joints, but is OK for attaching tubes to plates.)
Insulate the two tubes running between coldplate and radiator plate
from one another.
Put enough working fluid into the system to fill the tubing that is
soldered to the coldplate, but no more. Warm the system up so the
vapor drives all the air out, pinch the fill tube off and fold it
back, and braze the end shut. (It's not critical to get absolutely
all the air out.)
Making the radiator plate be above the coldplate (the boiler)
implements what amounts to an oldtime two-pipe water vapor heating
plant. Vapor goes up one pipe, condensed fluid returns via the
other. I lived in a house with such a system. The difference
between a vapor plant and a steam plant is pressure: the vapor plant
runs below atmospheric pressure, while the steam plant runs at or
slightly above.
Make sure that things are arranged so the returning fluid does not
pool anywhere but in the coldplate, or the heat pipe will bang like
an old steam heating system.
There is a brazing filler metal intended for copper-to-copper joints
that is widely used for freon systems:
http://www.uniweld.com/catalog/alloys/silver_brazing_alloys/phos_copper.htm.
The zero silver phos stuff is adequate, cheap and widely available.
While copper-to-copper needs no flux, copper-to-brass does, so also
get the flux. Plumbing supply houses and welding equipment stores
are likely sources. You will also need a torch or pair of torches
able to raise the tubing joints to an orange heat in a reasonable
length of time.
Depending on the chosen working fluid, the cold plate temperature
will not rise above the boiling point of the fluid unless the system
is too small (in radiator heat removal capacity) to easily handle the
10 or 20 thermal watts that are passing through.
What fluid to use? Anything common and thermally stable that does
not attack copper. Alcohol (methyl or ethyl) and water are common
choices, as are the various freons. I bet acetone would also work.
Anyway, one controls the coldplate temperature by a combination of
choice of working fluid and internal pressure.
I have seen commercially made heat pipes for cooling Intel CPUs
advertised, but I don't know that these units can be adapted.
Anyway, a heat pipe system will stabilize the coldplate temperature
fairly accurately despite variations in thermal load, has no moving
or electrical parts, and may be sufficient by itself. If not
sufficient, it can be used as the outer stage in a two-stage ovening
scheme.
Joe Gwinn
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Are we getting close to a Stirling engine running as a frig?
Don
Joe Gwinn
> A dodge occurs to me - a homebrew heat pipe:
> <http://en.wikipedia.org/wiki/Heat_pipe>.
>
> Make the cold plate of copper, to which is soldered a meandering
> piece of copper tubing, which tubing is also soldered to a copper
> radiator plate that is above the coldplate, forming a closed loop
> with a fill tube attached by a T. Braze all tubing connections, as
> for freon refrigeration systems. (Soft solder is too porous to work
> for the joints, but is OK for attaching tubes to plates.)
>
> Insulate the two tubes running between coldplate and radiator plate
> from one another.
>
> Put enough working fluid into the system to fill the tubing that is
> soldered to the coldplate, but no more. Warm the system up so the
> vapor drives all the air out, pinch the fill tube off and fold it
> back, and braze the end shut. (It's not critical to get absolutely
> all the air out.)
>
> Making the radiator plate be above the coldplate (the boiler)
> implements what amounts to an oldtime two-pipe water vapor heating
> plant. Vapor goes up one pipe, condensed fluid returns via the
> other. I lived in a house with such a system. The difference
> between a vapor plant and a steam plant is pressure: the vapor plant
> runs below atmospheric pressure, while the steam plant runs at or
> slightly above.
>
> Make sure that things are arranged so the returning fluid does not
> pool anywhere but in the coldplate, or the heat pipe will bang like
> an old steam heating system.
>
> There is a brazing filler metal intended for copper-to-copper joints
> that is widely used for freon systems:
> <http://www.uniweld.com/catalog/alloys/silver_brazing_alloys/phos_copper.htm>.
> The zero silver phos stuff is adequate, cheap and widely available.
> While copper-to-copper needs no flux, copper-to-brass does, so also
> get the flux. Plumbing supply houses and welding equipment stores
> are likely sources. You will also need a torch or pair of torches
> able to raise the tubing joints to an orange heat in a reasonable
> length of time.
>
> Depending on the chosen working fluid, the cold plate temperature
> will not rise above the boiling point of the fluid unless the system
> is too small (in radiator heat removal capacity) to easily handle the
> 10 or 20 thermal watts that are passing through.
>
> What fluid to use? Anything common and thermally stable that does
> not attack copper. Alcohol (methyl or ethyl) and water are common
> choices, as are the various freons. I bet acetone would also work.
> Anyway, one controls the coldplate temperature by a combination of
> choice of working fluid and internal pressure.
>
>
> I have seen commercially made heat pipes for cooling Intel CPUs
> advertised, but I don't know that these units can be adapted.
>
> Anyway, a heat pipe system will stabilize the coldplate temperature
> fairly accurately despite variations in thermal load, has no moving
> or electrical parts, and may be sufficient by itself. If not
> sufficient, it can be used as the outer stage in a two-stage ovening
> scheme.
>
>
> Joe Gwinn
>
> _______________________________________________
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
--
Dr. Don Latham AJ7LL
Six Mile Systems LLP
17850 Six Mile Road
POB 134
Huson, MT, 59846
VOX 406-626-4304
www.lightningforensics.com
www.sixmilesystems.com
BC
Bob Camp
Thu, Dec 24, 2009 8:32 PM
Hi
A heat pipe might work if the fluid had a sufficiently low boiling point. The rubidium isn't terribly tolerant of high temperatures, and I'm going to pick up some heat rise as I put it inside some baffles / shields. You need to find something that fits a fairly narrow window.
I suspect that a recirculating water loop is a more practical approach to carry away the heat. It's got a pump to move the water, but the rest of it is fairly simple.
Bob
On Dec 24, 2009, at 2:49 PM, Joe Gwinn wrote:
A dodge occurs to me - a homebrew heat pipe: http://en.wikipedia.org/wiki/Heat_pipe.
Make the cold plate of copper, to which is soldered a meandering piece of copper tubing, which tubing is also soldered to a copper radiator plate that is above the coldplate, forming a closed loop with a fill tube attached by a T. Braze all tubing connections, as for freon refrigeration systems. (Soft solder is too porous to work for the joints, but is OK for attaching tubes to plates.)
Insulate the two tubes running between coldplate and radiator plate from one another.
Put enough working fluid into the system to fill the tubing that is soldered to the coldplate, but no more. Warm the system up so the vapor drives all the air out, pinch the fill tube off and fold it back, and braze the end shut. (It's not critical to get absolutely all the air out.)
Making the radiator plate be above the coldplate (the boiler) implements what amounts to an oldtime two-pipe water vapor heating plant. Vapor goes up one pipe, condensed fluid returns via the other. I lived in a house with such a system. The difference between a vapor plant and a steam plant is pressure: the vapor plant runs below atmospheric pressure, while the steam plant runs at or slightly above.
Make sure that things are arranged so the returning fluid does not pool anywhere but in the coldplate, or the heat pipe will bang like an old steam heating system.
There is a brazing filler metal intended for copper-to-copper joints that is widely used for freon systems: http://www.uniweld.com/catalog/alloys/silver_brazing_alloys/phos_copper.htm. The zero silver phos stuff is adequate, cheap and widely available. While copper-to-copper needs no flux, copper-to-brass does, so also get the flux. Plumbing supply houses and welding equipment stores are likely sources. You will also need a torch or pair of torches able to raise the tubing joints to an orange heat in a reasonable length of time.
Depending on the chosen working fluid, the cold plate temperature will not rise above the boiling point of the fluid unless the system is too small (in radiator heat removal capacity) to easily handle the 10 or 20 thermal watts that are passing through.
What fluid to use? Anything common and thermally stable that does not attack copper. Alcohol (methyl or ethyl) and water are common choices, as are the various freons. I bet acetone would also work. Anyway, one controls the coldplate temperature by a combination of choice of working fluid and internal pressure.
I have seen commercially made heat pipes for cooling Intel CPUs advertised, but I don't know that these units can be adapted.
Anyway, a heat pipe system will stabilize the coldplate temperature fairly accurately despite variations in thermal load, has no moving or electrical parts, and may be sufficient by itself. If not sufficient, it can be used as the outer stage in a two-stage ovening scheme.
Joe Gwinn
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Hi
A heat pipe might work if the fluid had a sufficiently low boiling point. The rubidium isn't terribly tolerant of high temperatures, and I'm going to pick up some heat rise as I put it inside some baffles / shields. You need to find something that fits a fairly narrow window.
I suspect that a recirculating water loop is a more practical approach to carry away the heat. It's got a pump to move the water, but the rest of it is fairly simple.
Bob
On Dec 24, 2009, at 2:49 PM, Joe Gwinn wrote:
> A dodge occurs to me - a homebrew heat pipe: <http://en.wikipedia.org/wiki/Heat_pipe>.
>
> Make the cold plate of copper, to which is soldered a meandering piece of copper tubing, which tubing is also soldered to a copper radiator plate that is above the coldplate, forming a closed loop with a fill tube attached by a T. Braze all tubing connections, as for freon refrigeration systems. (Soft solder is too porous to work for the joints, but is OK for attaching tubes to plates.)
>
> Insulate the two tubes running between coldplate and radiator plate from one another.
>
> Put enough working fluid into the system to fill the tubing that is soldered to the coldplate, but no more. Warm the system up so the vapor drives all the air out, pinch the fill tube off and fold it back, and braze the end shut. (It's not critical to get absolutely all the air out.)
>
> Making the radiator plate be above the coldplate (the boiler) implements what amounts to an oldtime two-pipe water vapor heating plant. Vapor goes up one pipe, condensed fluid returns via the other. I lived in a house with such a system. The difference between a vapor plant and a steam plant is pressure: the vapor plant runs below atmospheric pressure, while the steam plant runs at or slightly above.
>
> Make sure that things are arranged so the returning fluid does not pool anywhere but in the coldplate, or the heat pipe will bang like an old steam heating system.
>
> There is a brazing filler metal intended for copper-to-copper joints that is widely used for freon systems: <http://www.uniweld.com/catalog/alloys/silver_brazing_alloys/phos_copper.htm>. The zero silver phos stuff is adequate, cheap and widely available. While copper-to-copper needs no flux, copper-to-brass does, so also get the flux. Plumbing supply houses and welding equipment stores are likely sources. You will also need a torch or pair of torches able to raise the tubing joints to an orange heat in a reasonable length of time.
>
> Depending on the chosen working fluid, the cold plate temperature will not rise above the boiling point of the fluid unless the system is too small (in radiator heat removal capacity) to easily handle the 10 or 20 thermal watts that are passing through.
>
> What fluid to use? Anything common and thermally stable that does not attack copper. Alcohol (methyl or ethyl) and water are common choices, as are the various freons. I bet acetone would also work. Anyway, one controls the coldplate temperature by a combination of choice of working fluid and internal pressure.
>
>
> I have seen commercially made heat pipes for cooling Intel CPUs advertised, but I don't know that these units can be adapted.
>
> Anyway, a heat pipe system will stabilize the coldplate temperature fairly accurately despite variations in thermal load, has no moving or electrical parts, and may be sufficient by itself. If not sufficient, it can be used as the outer stage in a two-stage ovening scheme.
>
>
> Joe Gwinn
>
> _______________________________________________
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
BG
Bruce Griffiths
Thu, Dec 24, 2009 8:41 PM
Depending on the required flow rate you may be able to use a peristaltic
pump.
Bruce
Bob Camp wrote:
Hi
A heat pipe might work if the fluid had a sufficiently low boiling point. The rubidium isn't terribly tolerant of high temperatures, and I'm going to pick up some heat rise as I put it inside some baffles / shields. You need to find something that fits a fairly narrow window.
I suspect that a recirculating water loop is a more practical approach to carry away the heat. It's got a pump to move the water, but the rest of it is fairly simple.
Bob
On Dec 24, 2009, at 2:49 PM, Joe Gwinn wrote:
A dodge occurs to me - a homebrew heat pipe:http://en.wikipedia.org/wiki/Heat_pipe.
Make the cold plate of copper, to which is soldered a meandering piece of copper tubing, which tubing is also soldered to a copper radiator plate that is above the coldplate, forming a closed loop with a fill tube attached by a T. Braze all tubing connections, as for freon refrigeration systems. (Soft solder is too porous to work for the joints, but is OK for attaching tubes to plates.)
Insulate the two tubes running between coldplate and radiator plate from one another.
Put enough working fluid into the system to fill the tubing that is soldered to the coldplate, but no more. Warm the system up so the vapor drives all the air out, pinch the fill tube off and fold it back, and braze the end shut. (It's not critical to get absolutely all the air out.)
Making the radiator plate be above the coldplate (the boiler) implements what amounts to an oldtime two-pipe water vapor heating plant. Vapor goes up one pipe, condensed fluid returns via the other. I lived in a house with such a system. The difference between a vapor plant and a steam plant is pressure: the vapor plant runs below atmospheric pressure, while the steam plant runs at or slightly above.
Make sure that things are arranged so the returning fluid does not pool anywhere but in the coldplate, or the heat pipe will bang like an old steam heating system.
There is a brazing filler metal intended for copper-to-copper joints that is widely used for freon systems:http://www.uniweld.com/catalog/alloys/silver_brazing_alloys/phos_copper.htm. The zero silver phos stuff is adequate, cheap and widely available. While copper-to-copper needs no flux, copper-to-brass does, so also get the flux. Plumbing supply houses and welding equipment stores are likely sources. You will also need a torch or pair of torches able to raise the tubing joints to an orange heat in a reasonable length of time.
Depending on the chosen working fluid, the cold plate temperature will not rise above the boiling point of the fluid unless the system is too small (in radiator heat removal capacity) to easily handle the 10 or 20 thermal watts that are passing through.
What fluid to use? Anything common and thermally stable that does not attack copper. Alcohol (methyl or ethyl) and water are common choices, as are the various freons. I bet acetone would also work. Anyway, one controls the coldplate temperature by a combination of choice of working fluid and internal pressure.
I have seen commercially made heat pipes for cooling Intel CPUs advertised, but I don't know that these units can be adapted.
Anyway, a heat pipe system will stabilize the coldplate temperature fairly accurately despite variations in thermal load, has no moving or electrical parts, and may be sufficient by itself. If not sufficient, it can be used as the outer stage in a two-stage ovening scheme.
Joe Gwinn
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Depending on the required flow rate you may be able to use a peristaltic
pump.
Bruce
Bob Camp wrote:
> Hi
>
> A heat pipe might work if the fluid had a sufficiently low boiling point. The rubidium isn't terribly tolerant of high temperatures, and I'm going to pick up some heat rise as I put it inside some baffles / shields. You need to find something that fits a fairly narrow window.
>
> I suspect that a recirculating water loop is a more practical approach to carry away the heat. It's got a pump to move the water, but the rest of it is fairly simple.
>
> Bob
>
>
> On Dec 24, 2009, at 2:49 PM, Joe Gwinn wrote:
>
>
>> A dodge occurs to me - a homebrew heat pipe:<http://en.wikipedia.org/wiki/Heat_pipe>.
>>
>> Make the cold plate of copper, to which is soldered a meandering piece of copper tubing, which tubing is also soldered to a copper radiator plate that is above the coldplate, forming a closed loop with a fill tube attached by a T. Braze all tubing connections, as for freon refrigeration systems. (Soft solder is too porous to work for the joints, but is OK for attaching tubes to plates.)
>>
>> Insulate the two tubes running between coldplate and radiator plate from one another.
>>
>> Put enough working fluid into the system to fill the tubing that is soldered to the coldplate, but no more. Warm the system up so the vapor drives all the air out, pinch the fill tube off and fold it back, and braze the end shut. (It's not critical to get absolutely all the air out.)
>>
>> Making the radiator plate be above the coldplate (the boiler) implements what amounts to an oldtime two-pipe water vapor heating plant. Vapor goes up one pipe, condensed fluid returns via the other. I lived in a house with such a system. The difference between a vapor plant and a steam plant is pressure: the vapor plant runs below atmospheric pressure, while the steam plant runs at or slightly above.
>>
>> Make sure that things are arranged so the returning fluid does not pool anywhere but in the coldplate, or the heat pipe will bang like an old steam heating system.
>>
>> There is a brazing filler metal intended for copper-to-copper joints that is widely used for freon systems:<http://www.uniweld.com/catalog/alloys/silver_brazing_alloys/phos_copper.htm>. The zero silver phos stuff is adequate, cheap and widely available. While copper-to-copper needs no flux, copper-to-brass does, so also get the flux. Plumbing supply houses and welding equipment stores are likely sources. You will also need a torch or pair of torches able to raise the tubing joints to an orange heat in a reasonable length of time.
>>
>> Depending on the chosen working fluid, the cold plate temperature will not rise above the boiling point of the fluid unless the system is too small (in radiator heat removal capacity) to easily handle the 10 or 20 thermal watts that are passing through.
>>
>> What fluid to use? Anything common and thermally stable that does not attack copper. Alcohol (methyl or ethyl) and water are common choices, as are the various freons. I bet acetone would also work. Anyway, one controls the coldplate temperature by a combination of choice of working fluid and internal pressure.
>>
>>
>> I have seen commercially made heat pipes for cooling Intel CPUs advertised, but I don't know that these units can be adapted.
>>
>> Anyway, a heat pipe system will stabilize the coldplate temperature fairly accurately despite variations in thermal load, has no moving or electrical parts, and may be sufficient by itself. If not sufficient, it can be used as the outer stage in a two-stage ovening scheme.
>>
>>
>> Joe Gwinn
>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts@febo.com
>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>>
>>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
>
BC
Bob Camp
Thu, Dec 24, 2009 8:53 PM
Hi
Exactly right. You don't need a multiple horsepower pump to make it happen. WIth some careful thought, you may be able to share one pump between the set of standards (back to correlation issues though ...)
Bob
On Dec 24, 2009, at 3:41 PM, Bruce Griffiths wrote:
Depending on the required flow rate you may be able to use a peristaltic pump.
Bruce
Bob Camp wrote:
Hi
A heat pipe might work if the fluid had a sufficiently low boiling point. The rubidium isn't terribly tolerant of high temperatures, and I'm going to pick up some heat rise as I put it inside some baffles / shields. You need to find something that fits a fairly narrow window.
I suspect that a recirculating water loop is a more practical approach to carry away the heat. It's got a pump to move the water, but the rest of it is fairly simple.
Bob
On Dec 24, 2009, at 2:49 PM, Joe Gwinn wrote:
A dodge occurs to me - a homebrew heat pipe:http://en.wikipedia.org/wiki/Heat_pipe.
Make the cold plate of copper, to which is soldered a meandering piece of copper tubing, which tubing is also soldered to a copper radiator plate that is above the coldplate, forming a closed loop with a fill tube attached by a T. Braze all tubing connections, as for freon refrigeration systems. (Soft solder is too porous to work for the joints, but is OK for attaching tubes to plates.)
Insulate the two tubes running between coldplate and radiator plate from one another.
Put enough working fluid into the system to fill the tubing that is soldered to the coldplate, but no more. Warm the system up so the vapor drives all the air out, pinch the fill tube off and fold it back, and braze the end shut. (It's not critical to get absolutely all the air out.)
Making the radiator plate be above the coldplate (the boiler) implements what amounts to an oldtime two-pipe water vapor heating plant. Vapor goes up one pipe, condensed fluid returns via the other. I lived in a house with such a system. The difference between a vapor plant and a steam plant is pressure: the vapor plant runs below atmospheric pressure, while the steam plant runs at or slightly above.
Make sure that things are arranged so the returning fluid does not pool anywhere but in the coldplate, or the heat pipe will bang like an old steam heating system.
There is a brazing filler metal intended for copper-to-copper joints that is widely used for freon systems:http://www.uniweld.com/catalog/alloys/silver_brazing_alloys/phos_copper.htm. The zero silver phos stuff is adequate, cheap and widely available. While copper-to-copper needs no flux, copper-to-brass does, so also get the flux. Plumbing supply houses and welding equipment stores are likely sources. You will also need a torch or pair of torches able to raise the tubing joints to an orange heat in a reasonable length of time.
Depending on the chosen working fluid, the cold plate temperature will not rise above the boiling point of the fluid unless the system is too small (in radiator heat removal capacity) to easily handle the 10 or 20 thermal watts that are passing through.
What fluid to use? Anything common and thermally stable that does not attack copper. Alcohol (methyl or ethyl) and water are common choices, as are the various freons. I bet acetone would also work. Anyway, one controls the coldplate temperature by a combination of choice of working fluid and internal pressure.
I have seen commercially made heat pipes for cooling Intel CPUs advertised, but I don't know that these units can be adapted.
Anyway, a heat pipe system will stabilize the coldplate temperature fairly accurately despite variations in thermal load, has no moving or electrical parts, and may be sufficient by itself. If not sufficient, it can be used as the outer stage in a two-stage ovening scheme.
Joe Gwinn
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Hi
Exactly right. You don't need a multiple horsepower pump to make it happen. WIth some careful thought, you may be able to share one pump between the set of standards (back to correlation issues though ...)
Bob
On Dec 24, 2009, at 3:41 PM, Bruce Griffiths wrote:
> Depending on the required flow rate you may be able to use a peristaltic pump.
>
> Bruce
>
> Bob Camp wrote:
>> Hi
>>
>> A heat pipe might work if the fluid had a sufficiently low boiling point. The rubidium isn't terribly tolerant of high temperatures, and I'm going to pick up some heat rise as I put it inside some baffles / shields. You need to find something that fits a fairly narrow window.
>>
>> I suspect that a recirculating water loop is a more practical approach to carry away the heat. It's got a pump to move the water, but the rest of it is fairly simple.
>>
>> Bob
>>
>>
>> On Dec 24, 2009, at 2:49 PM, Joe Gwinn wrote:
>>
>>
>>> A dodge occurs to me - a homebrew heat pipe:<http://en.wikipedia.org/wiki/Heat_pipe>.
>>>
>>> Make the cold plate of copper, to which is soldered a meandering piece of copper tubing, which tubing is also soldered to a copper radiator plate that is above the coldplate, forming a closed loop with a fill tube attached by a T. Braze all tubing connections, as for freon refrigeration systems. (Soft solder is too porous to work for the joints, but is OK for attaching tubes to plates.)
>>>
>>> Insulate the two tubes running between coldplate and radiator plate from one another.
>>>
>>> Put enough working fluid into the system to fill the tubing that is soldered to the coldplate, but no more. Warm the system up so the vapor drives all the air out, pinch the fill tube off and fold it back, and braze the end shut. (It's not critical to get absolutely all the air out.)
>>>
>>> Making the radiator plate be above the coldplate (the boiler) implements what amounts to an oldtime two-pipe water vapor heating plant. Vapor goes up one pipe, condensed fluid returns via the other. I lived in a house with such a system. The difference between a vapor plant and a steam plant is pressure: the vapor plant runs below atmospheric pressure, while the steam plant runs at or slightly above.
>>>
>>> Make sure that things are arranged so the returning fluid does not pool anywhere but in the coldplate, or the heat pipe will bang like an old steam heating system.
>>>
>>> There is a brazing filler metal intended for copper-to-copper joints that is widely used for freon systems:<http://www.uniweld.com/catalog/alloys/silver_brazing_alloys/phos_copper.htm>. The zero silver phos stuff is adequate, cheap and widely available. While copper-to-copper needs no flux, copper-to-brass does, so also get the flux. Plumbing supply houses and welding equipment stores are likely sources. You will also need a torch or pair of torches able to raise the tubing joints to an orange heat in a reasonable length of time.
>>>
>>> Depending on the chosen working fluid, the cold plate temperature will not rise above the boiling point of the fluid unless the system is too small (in radiator heat removal capacity) to easily handle the 10 or 20 thermal watts that are passing through.
>>>
>>> What fluid to use? Anything common and thermally stable that does not attack copper. Alcohol (methyl or ethyl) and water are common choices, as are the various freons. I bet acetone would also work. Anyway, one controls the coldplate temperature by a combination of choice of working fluid and internal pressure.
>>>
>>>
>>> I have seen commercially made heat pipes for cooling Intel CPUs advertised, but I don't know that these units can be adapted.
>>>
>>> Anyway, a heat pipe system will stabilize the coldplate temperature fairly accurately despite variations in thermal load, has no moving or electrical parts, and may be sufficient by itself. If not sufficient, it can be used as the outer stage in a two-stage ovening scheme.
>>>
>>>
>>> Joe Gwinn
>>>
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts@febo.com
>>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
>>>
>>>
>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts@febo.com
>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
>>
>>
>
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
RD
Robert Darlington
Fri, Dec 25, 2009 12:14 AM
On Thu, Dec 24, 2009 at 1:32 PM, Bob Camp lists@cq.nu wrote:
Hi
A heat pipe might work if the fluid had a sufficiently low boiling point.
The working fluid in a heat pipe will boil at every temperature above its
melting point. I tend to use water because it's cheap, but have made them
with 3M "engineered fluids", Fluorinert, and denatured alcohol. I've found
that ordinary solder works just fine. A trick to make these things easy to
build is to use a ball valve at the top (I'm assuming there is a top and
we're going with gravity return because it's simple). I've got a few that
are still under vacuum for several years now in this configuration. My
giant heat pipe of doom is a 10 foot stick of 1/2" copper with a ball valve
at one end and an end cap at the other. There is perhaps 100ml water in
there total, and no air. You can either boil the liquid until it builds up
a nice head of steam, or go the easy way and pull a vacuum with a pump and
just close the valve. These things are incredible. If you pack snow around
the end of this thing, the other end that is ten feet away gets cold almost
immediately. They want to stay isothermal and the heat transfer is at the
speed of sound through the working fluid. Delays are introduced because
you're dealing with a thermal mass of copper pipe that needs to change
temperature along with the working fluid so it's not quite instant, but
still about 10,000 times faster heat transfer than copper by itself. They
are certainly handy for getting heat out of confined spaces.
-Bob
The rubidium isn't terribly tolerant of high temperatures, and I'm going to
pick up some heat rise as I put it inside some baffles / shields. You need
to find something that fits a fairly narrow window.
I suspect that a recirculating water loop is a more practical approach to
carry away the heat. It's got a pump to move the water, but the rest of it
is fairly simple.
Bob
On Dec 24, 2009, at 2:49 PM, Joe Gwinn wrote:
A dodge occurs to me - a homebrew heat pipe: <
Make the cold plate of copper, to which is soldered a meandering piece of
copper tubing, which tubing is also soldered to a copper radiator plate that
is above the coldplate, forming a closed loop with a fill tube attached by a
T. Braze all tubing connections, as for freon refrigeration systems. (Soft
solder is too porous to work for the joints, but is OK for attaching tubes
to plates.)
Insulate the two tubes running between coldplate and radiator plate from
Put enough working fluid into the system to fill the tubing that is
soldered to the coldplate, but no more. Warm the system up so the vapor
drives all the air out, pinch the fill tube off and fold it back, and braze
the end shut. (It's not critical to get absolutely all the air out.)
Making the radiator plate be above the coldplate (the boiler) implements
what amounts to an oldtime two-pipe water vapor heating plant. Vapor goes
up one pipe, condensed fluid returns via the other. I lived in a house with
such a system. The difference between a vapor plant and a steam plant is
pressure: the vapor plant runs below atmospheric pressure, while the steam
plant runs at or slightly above.
Make sure that things are arranged so the returning fluid does not pool
anywhere but in the coldplate, or the heat pipe will bang like an old steam
heating system.
There is a brazing filler metal intended for copper-to-copper joints that
is widely used for freon systems: <
http://www.uniweld.com/catalog/alloys/silver_brazing_alloys/phos_copper.htm>.
The zero silver phos stuff is adequate, cheap and widely available. While
copper-to-copper needs no flux, copper-to-brass does, so also get the flux.
Plumbing supply houses and welding equipment stores are likely sources.
You will also need a torch or pair of torches able to raise the tubing
joints to an orange heat in a reasonable length of time.
Depending on the chosen working fluid, the cold plate temperature will
not rise above the boiling point of the fluid unless the system is too small
(in radiator heat removal capacity) to easily handle the 10 or 20 thermal
watts that are passing through.
What fluid to use? Anything common and thermally stable that does not
attack copper. Alcohol (methyl or ethyl) and water are common choices, as
are the various freons. I bet acetone would also work. Anyway, one controls
the coldplate temperature by a combination of choice of working fluid and
internal pressure.
I have seen commercially made heat pipes for cooling Intel CPUs
advertised, but I don't know that these units can be adapted.
Anyway, a heat pipe system will stabilize the coldplate temperature
fairly accurately despite variations in thermal load, has no moving or
electrical parts, and may be sufficient by itself. If not sufficient, it
can be used as the outer stage in a two-stage ovening scheme.
and follow the instructions there.
On Thu, Dec 24, 2009 at 1:32 PM, Bob Camp <lists@cq.nu> wrote:
> Hi
>
> A heat pipe might work if the fluid had a sufficiently low boiling point.
The working fluid in a heat pipe will boil at every temperature above its
melting point. I tend to use water because it's cheap, but have made them
with 3M "engineered fluids", Fluorinert, and denatured alcohol. I've found
that ordinary solder works just fine. A trick to make these things easy to
build is to use a ball valve at the top (I'm assuming there is a top and
we're going with gravity return because it's simple). I've got a few that
are still under vacuum for several years now in this configuration. My
giant heat pipe of doom is a 10 foot stick of 1/2" copper with a ball valve
at one end and an end cap at the other. There is perhaps 100ml water in
there total, and no air. You can either boil the liquid until it builds up
a nice head of steam, or go the easy way and pull a vacuum with a pump and
just close the valve. These things are incredible. If you pack snow around
the end of this thing, the other end that is ten feet away gets cold almost
immediately. They want to stay isothermal and the heat transfer is at the
speed of sound through the working fluid. Delays are introduced because
you're dealing with a thermal mass of copper pipe that needs to change
temperature along with the working fluid so it's not quite instant, but
still about 10,000 times faster heat transfer than copper by itself. They
are certainly handy for getting heat out of confined spaces.
-Bob
> The rubidium isn't terribly tolerant of high temperatures, and I'm going to
> pick up some heat rise as I put it inside some baffles / shields. You need
> to find something that fits a fairly narrow window.
>
> I suspect that a recirculating water loop is a more practical approach to
> carry away the heat. It's got a pump to move the water, but the rest of it
> is fairly simple.
>
> Bob
>
>
> On Dec 24, 2009, at 2:49 PM, Joe Gwinn wrote:
>
> > A dodge occurs to me - a homebrew heat pipe: <
> http://en.wikipedia.org/wiki/Heat_pipe>.
> >
> > Make the cold plate of copper, to which is soldered a meandering piece of
> copper tubing, which tubing is also soldered to a copper radiator plate that
> is above the coldplate, forming a closed loop with a fill tube attached by a
> T. Braze all tubing connections, as for freon refrigeration systems. (Soft
> solder is too porous to work for the joints, but is OK for attaching tubes
> to plates.)
> >
> > Insulate the two tubes running between coldplate and radiator plate from
> one another.
> >
> > Put enough working fluid into the system to fill the tubing that is
> soldered to the coldplate, but no more. Warm the system up so the vapor
> drives all the air out, pinch the fill tube off and fold it back, and braze
> the end shut. (It's not critical to get absolutely all the air out.)
> >
> > Making the radiator plate be above the coldplate (the boiler) implements
> what amounts to an oldtime two-pipe water vapor heating plant. Vapor goes
> up one pipe, condensed fluid returns via the other. I lived in a house with
> such a system. The difference between a vapor plant and a steam plant is
> pressure: the vapor plant runs below atmospheric pressure, while the steam
> plant runs at or slightly above.
> >
> > Make sure that things are arranged so the returning fluid does not pool
> anywhere but in the coldplate, or the heat pipe will bang like an old steam
> heating system.
> >
> > There is a brazing filler metal intended for copper-to-copper joints that
> is widely used for freon systems: <
> http://www.uniweld.com/catalog/alloys/silver_brazing_alloys/phos_copper.htm>.
> The zero silver phos stuff is adequate, cheap and widely available. While
> copper-to-copper needs no flux, copper-to-brass does, so also get the flux.
> Plumbing supply houses and welding equipment stores are likely sources.
> You will also need a torch or pair of torches able to raise the tubing
> joints to an orange heat in a reasonable length of time.
> >
> > Depending on the chosen working fluid, the cold plate temperature will
> not rise above the boiling point of the fluid unless the system is too small
> (in radiator heat removal capacity) to easily handle the 10 or 20 thermal
> watts that are passing through.
> >
> > What fluid to use? Anything common and thermally stable that does not
> attack copper. Alcohol (methyl or ethyl) and water are common choices, as
> are the various freons. I bet acetone would also work. Anyway, one controls
> the coldplate temperature by a combination of choice of working fluid and
> internal pressure.
> >
> >
> > I have seen commercially made heat pipes for cooling Intel CPUs
> advertised, but I don't know that these units can be adapted.
> >
> > Anyway, a heat pipe system will stabilize the coldplate temperature
> fairly accurately despite variations in thermal load, has no moving or
> electrical parts, and may be sufficient by itself. If not sufficient, it
> can be used as the outer stage in a two-stage ovening scheme.
> >
> >
> > Joe Gwinn
> >
> > _______________________________________________
> > time-nuts mailing list -- time-nuts@febo.com
> > To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> > and follow the instructions there.
> >
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
