One can regard the needle of a syringe as a very thin pipe, but it is also
a very short pipe. Syringes are used in microscale organic chemistry labs
to transfer small quantities of fluids. If one wanted to avoid syringes
and instead transfer the same quantities of liquids along a pipe from a
small tank of the liquid, I imagine one would need a pipe as thin as a
syringe needle. At any rate, one can choose to do so at the design level.
(I realize there might be more resistance along the pipe and considerable
difficulty clearing a blocked pipe and possible problems due to sagging of
the pipe, but never mind.)

I have no laboratory and no shop and have no plans to actually do any of this.
I'm just thinking about how it might be done. Since the solution involves
a problem in metal work, I think it is appropriate to ask about it here.

The questions a
(1) How would one make a long metal pipe (e.g. a few feet) which is as thin
and as hollow as a syringe needle?
(2) And what if one wanted the pipe to follow some path other than straight?
Probably it is too thin to bend without closing it off, no matter how
carefully one tries to do it. Maybe one has to make miniature versions
of all of the standard plumbing fixtures and, to make sure the connections
are strong enough, one allows the outer diameters of the pipes to increase
where the threads are. So that feature of the pipe design would also have
to be included.

Ignorantly,
Allan Adler


************************************************** **************************
* *
* Disclaimer: I am a guest and *not* a member of the MIT Artificial *
* Intelligence Lab. My actions and comments do not reflect *
* in any way on MIT. Moreover, I am nowhere near the Boston *
* metropolitan area. *
* *
************************************************** **************************

Allan Adler wrote in
:


One can regard the needle of a syringe as a very thin pipe, but it is
also a very short pipe. Syringes are used in microscale organic
chemistry labs to transfer small quantities of fluids. If one wanted
to avoid syringes and instead transfer the same quantities of liquids
along a pipe from a small tank of the liquid, I imagine one would need
a pipe as thin as a syringe needle. At any rate, one can choose to do
so at the design level. (I realize there might be more resistance
along the pipe and considerable difficulty clearing a blocked pipe and
possible problems due to sagging of the pipe, but never mind.)

I have no laboratory and no shop and have no plans to actually do any
of this. I'm just thinking about how it might be done. Since the
solution involves a problem in metal work, I think it is appropriate
to ask about it here.

The questions a
(1) How would one make a long metal pipe (e.g. a few feet) which is as
thin
and as hollow as a syringe needle?
(2) And what if one wanted the pipe to follow some path other than
straight?
Probably it is too thin to bend without closing it off, no matter
how carefully one tries to do it. Maybe one has to make miniature
versions of all of the standard plumbing fixtures and, to make
sure the connections are strong enough, one allows the outer
diameters of the pipes to increase where the threads are. So that
feature of the pipe design would also have to be included.

Ignorantly,
Allan Adler


************************************************** *********************
***** *
* * Disclaimer: I am a guest and *not* a member of the MIT
Artificial * * Intelligence Lab. My actions and
comments do not reflect * * in any way on MIT.
Moreover, I am nowhere near the Boston * * metropolitan
area. * *
*
************************************************** *********************
*****





Would it not be the same to use a larger, more easily manufacturable pipe
(read cost) for most of the conduit with only a metering section near the
end? What process would require this small of a conduit for any
appreciable length? The mechanical properties of this type of conduit
would be terrible, subseptable to any vibration, mechanical distortion
and temperature gradients.


--
Anthony

You can't 'idiot proof' anything....every time you try, they just make
better idiots.

Remove sp to reply via email

In article ,
Allan Adler wrote:

The questions a
(1) How would one make a long metal pipe (e.g. a few feet) which is as thin
and as hollow as a syringe needle?
(2) And what if one wanted the pipe to follow some path other than straight?
Probably it is too thin to bend without closing it off, no matter how
carefully one tries to do it. Maybe one has to make miniature versions
of all of the standard plumbing fixtures and, to make sure the connections
are strong enough, one allows the outer diameters of the pipes to increase
where the threads are. So that feature of the pipe design would also have
to be included.

When I needed tiny pipe recently, I used a piece of refrigerator
cappilary fropm a junk refrigerator. Probably smaller ID than a syringe
but can be bent without closing.

--
free men own guns - slaves don't
www.geocities.com/CapitolHill/5357/

"Allan Adler" wrote in message
...

The questions a
(1) How would one make a long metal pipe (e.g. a few feet) which is as
thin
and as hollow as a syringe needle?

As a thought exercise only, I offer the following possibilities:

1a-start off with a flat sheet, of the right width. form it first into a
"u" shape, then into an "0" shape. gently heat the resultant shape using
electricity to "weld" the seam together.
1b- syringe needles, joined end to end, with flared joints
1c- make a mold, using tungsten wire as the core.
1d-use an extruding mold, and a metal that's soft enough and melts at a low
enough temperature to pass through it. You specify "metal". You don't say
which type.

(2) And what if one wanted the pipe to follow some path other than
straight?
Probably it is too thin to bend without closing it off, no matter how
carefully one tries to do it. Maybe one has to make miniature versions
of all of the standard plumbing fixtures and, to make sure the
connections
are strong enough, one allows the outer diameters of the pipes to
increase
where the threads are. So that feature of the pipe design would also
have
to be included.

2a-compression fittings
2b-make the bends big enough and the tubing won't kink.




Ignorantly,
Allan Adler



************************************************** **************************
*
*
* Disclaimer: I am a guest and *not* a member of the MIT Artificial
*
* Intelligence Lab. My actions and comments do not reflect
*
* in any way on MIT. Moreover, I am nowhere near the Boston
*
* metropolitan area.
*
*
*

************************************************** **************************

First of all this type of device is common in precision assembly lines
for dispensing glues. Pumping fluids long distances through very narrow
pipes is extremely inefficient so a high pressure hose feeds a manifold
with capillary tube size nozzles. For two part resin/catylist systems
two hoses feed a mixing chamber at the manifold.

Capillary tube is available in copper, aluminum, stainless steel and
several plastics. There are even some aramid capillaries with ODs
smaller than a human hair. Refrigeration thermostats use a very small
ID capillary tube to connect sensor bulbs to a pressure switch. It is
relatively thick walled compared to the ID so that it can be bent
without crimping.

Metal and thermoplastic tube is made with water cooled a die.
(Thermoset plastics use a heated die.) The die has a hole the size of
the tube OD. A pin the size of the ID is centered in the hole. A metal
alloy or thermoplastic polymer just at the liquidus point is extruded
through under high pressure and solidifies as it exits the other side.

Allan Adler wrote:
One can regard the needle of a syringe as a very thin pipe, but it is also
a very short pipe. Syringes are used in microscale organic chemistry labs
to transfer small quantities of fluids. If one wanted to avoid syringes
and instead transfer the same quantities of liquids along a pipe from a
small tank of the liquid, I imagine one would need a pipe as thin as a
syringe needle. At any rate, one can choose to do so at the design level.
(I realize there might be more resistance along the pipe and considerable
difficulty clearing a blocked pipe and possible problems due to sagging of
the pipe, but never mind.)

I have no laboratory and no shop and have no plans to actually do any of this.
I'm just thinking about how it might be done. Since the solution involves
a problem in metal work, I think it is appropriate to ask about it here.

The questions a
(1) How would one make a long metal pipe (e.g. a few feet) which is as thin
and as hollow as a syringe needle?
(2) And what if one wanted the pipe to follow some path other than straight?
Probably it is too thin to bend without closing it off, no matter how
carefully one tries to do it. Maybe one has to make miniature versions
of all of the standard plumbing fixtures and, to make sure the connections
are strong enough, one allows the outer diameters of the pipes to increase
where the threads are. So that feature of the pipe design would also have
to be included.

Ignorantly,
Allan Adler


************************************************** **************************
* *
* Disclaimer: I am a guest and *not* a member of the MIT Artificial *
* Intelligence Lab. My actions and comments do not reflect *
* in any way on MIT. Moreover, I am nowhere near the Boston *
* metropolitan area. *
* *
************************************************** **************************



--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

Allan Adler wrote in message ...
(1) How would one make a long metal pipe (e.g. a few feet) which is as thin
and as hollow as a syringe needle?

http://www.smallparts.com/products/descriptions/htx.cfm
Hypodermic Tubing, 304SS, welded and drawn - which means they fold
a sheet into a "U", then close it the rest of the way and weld the
seam, then draw it thru a die (and possibly over a mandrel) to smooth
the seam and reduce the diameter. They have 3' lengths as small as
0.012 OD and 0.006 ID. (I expect this is done with multiple stages
of drawing.)

http://www.smallparts.com/products/d...tx,%20ctni.cfm
Capillary tubing - they don't say how it is made, but I imagine it is
also drawn down from a larger size. The wall is thicker, and it doesn't
come as small a hypodermic tube - they have several sizes, all 0.062 OD,
with IDs ranging from 0.005 to 0.030. It is available in _much_ longer
lengths, up to 100'. They coil it - the wall is thick enough that you
can handle it much like wire of the same OD.

(2) And what if one wanted the pipe to follow some path other than straight?
Probably it is too thin to bend without closing it off, no matter how
carefully one tries to do it. Maybe one has to make miniature versions
of all of the standard plumbing fixtures and, to make sure the connections
are strong enough, one allows the outer diameters of the pipes to increase
where the threads are. So that feature of the pipe design would also have
to be included.

The capillary tubing has walls thick enough that you _can_ bend it into
a moderately tight raduis without pinching off. The hypodermic tubing
would be more difficult. You could fill it with a low melting alloy like
Cerrosafe, bend, then melt out the alloy.

John Kasunich

In article , Allan Adler says...

I have no laboratory and no shop and have no plans to actually do any of this.
I'm just thinking about how it might be done. Since the solution involves
a problem in metal work, I think it is appropriate to ask about it here.

Microbore capillary tubine is commonly manfuactured from a variety
of materials, but specialty draw houses like Uniform Tubes. Basically
a billet of material is gun drilled, and then drawn down over
successive draws to achieve the desired wall and bore dimensions.

Bending small diameter tubing such as this is trivially
done by filling the tubing with water, and then freezing the
water with liquid nitrogen. As long as the water is kept
solid during the bending by repeated re-freezing, the tube
will not collapse or kink. The water is blown out after
all the bending is complete.

Jim

==================================================
please reply to:
JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com
==================================================

"Wayne Bengtsson" wrote in message ...
"Allan Adler" wrote in message
...

The questions a
(1) How would one make a long metal pipe (e.g. a few feet) which is as
thin
and as hollow as a syringe needle?

As a thought exercise only, I offer the following possibilities:

1a-start off with a flat sheet, of the right width. form it first into a
"u" shape, then into an "0" shape. gently heat the resultant shape using
electricity to "weld" the seam together.
1b- syringe needles, joined end to end, with flared joints
1c- make a mold, using tungsten wire as the core.
1d-use an extruding mold, and a metal that's soft enough and melts at a low
enough temperature to pass through it. You specify "metal". You don't say
which type.

(2) And what if one wanted the pipe to follow some path other than
straight?
Probably it is too thin to bend without closing it off, no matter how
carefully one tries to do it. Maybe one has to make miniature versions
of all of the standard plumbing fixtures and, to make sure the
connections
are strong enough, one allows the outer diameters of the pipes to
increase
where the threads are. So that feature of the pipe design would also
have
to be included.

2a-compression fittings
2b-make the bends big enough and the tubing won't kink.




Ignorantly,
Allan Adler



************************************************** **************************
*
*
* Disclaimer: I am a guest and *not* a member of the MIT Artificial
*
* Intelligence Lab. My actions and comments do not reflect
*
* in any way on MIT. Moreover, I am nowhere near the Boston
*
* metropolitan area.
*
*
*

************************************************** **************************



I'd just order ss hypodermic tubing and components from
smallparts.com.
They're not cheap, but a hell of a lot faster and easier than making
the tubing, connectors, and fittings yourself.
As far as bending goes... I never tried to bend hypo tube and I hope
I never have to.

John B.

P.S. I have no connection with Small Parts Inc. (In fact, I think some
of their prices are "down right criminal") but when it comes to low
volume orders of small components, they're often the only source -
that I have found anyway.

The tubing is available as hypodermic tubing in at least 6 foot lengths. I
use it at work quite often, in .109 diameter. Other sizes are available.

RJ

"Allan Adler" wrote in message
...

One can regard the needle of a syringe as a very thin pipe, but it is also
a very short pipe. Syringes are used in microscale organic chemistry labs
to transfer small quantities of fluids. If one wanted to avoid syringes
and instead transfer the same quantities of liquids along a pipe from a
small tank of the liquid, I imagine one would need a pipe as thin as a
syringe needle. At any rate, one can choose to do so at the design level.
(I realize there might be more resistance along the pipe and considerable
difficulty clearing a blocked pipe and possible problems due to sagging of
the pipe, but never mind.)

I have no laboratory and no shop and have no plans to actually do any of
this.
I'm just thinking about how it might be done. Since the solution involves
a problem in metal work, I think it is appropriate to ask about it here.

The questions a
(1) How would one make a long metal pipe (e.g. a few feet) which is as
thin
and as hollow as a syringe needle?
(2) And what if one wanted the pipe to follow some path other than
straight?
Probably it is too thin to bend without closing it off, no matter how
carefully one tries to do it. Maybe one has to make miniature versions
of all of the standard plumbing fixtures and, to make sure the
connections
are strong enough, one allows the outer diameters of the pipes to
increase
where the threads are. So that feature of the pipe design would also
have
to be included.

Ignorantly,
Allan Adler



************************************************** **************************
*
*
* Disclaimer: I am a guest and *not* a member of the MIT Artificial
*
* Intelligence Lab. My actions and comments do not reflect
*
* in any way on MIT. Moreover, I am nowhere near the Boston
*
* metropolitan area.
*
*
*

************************************************** **************************

Impractical. The design should pipe the compound through a
regular, small tube of reasonable dimension, then meter the
compound through an orifice at the end.
JR
Dweller in the cellar

Allan Adler wrote:

One can regard the needle of a syringe as a very thin pipe, but it is also
a very short pipe. Syringes are used in microscale organic chemistry labs
to transfer small quantities of fluids. If one wanted to avoid syringes
and instead transfer the same quantities of liquids along a pipe from a
small tank of the liquid, I imagine one would need a pipe as thin as a
syringe needle. At any rate, one can choose to do so at the design level.
(I realize there might be more resistance along the pipe and considerable
difficulty clearing a blocked pipe and possible problems due to sagging of
the pipe, but never mind.)

I have no laboratory and no shop and have no plans to actually do any of this.
I'm just thinking about how it might be done. Since the solution involves
a problem in metal work, I think it is appropriate to ask about it here.

The questions a
(1) How would one make a long metal pipe (e.g. a few feet) which is as thin
and as hollow as a syringe needle?
(2) And what if one wanted the pipe to follow some path other than straight?
Probably it is too thin to bend without closing it off, no matter how
carefully one tries to do it. Maybe one has to make miniature versions
of all of the standard plumbing fixtures and, to make sure the connections
are strong enough, one allows the outer diameters of the pipes to increase
where the threads are. So that feature of the pipe design would also have
to be included.

Ignorantly,
Allan Adler


************************************************** **************************
* *
* Disclaimer: I am a guest and *not* a member of the MIT Artificial *
* Intelligence Lab. My actions and comments do not reflect *
* in any way on MIT. Moreover, I am nowhere near the Boston *
* metropolitan area. *
* *
************************************************** **************************

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