| Topic: |
Science > Physics |
| User: |
"Marshall Dudley" |
| Date: |
17 Sep 2005 11:08:03 AM |
| Object: |
drip viscosity measurements |
I am wanting to measure the viscosity of some oils at different
temperatures and since I do not need high accuracy, was trying to use a
drip method of viscosity measurement. I took a syringe that has a long
plastic tip on it and was trying to use it. It was nice since it was
marked off in 1 cc increments up to 12 cc. This allowed me to easily
put more "head" on lighter liquids to compensate for the difference in
density. For instance for water I can fill it to the 10 cc mark and
measure the time it takes to drain out to 9 cc, and for oil that has a
density of .9, I can fill it to 11 and let it drain to 10. When I ran
some viscosity tests the results seemed to be very non-linear.
liquid expected viscosity measured time
water 1 4 seconds
diesel 2-3 8 seconds
soy oil 60-80 60 seconds
I believe that the non linearity is most likely due to the energy
necessary to accelerate the liquid through the end of the tip for the
thinner liquids is slowing it down, so water it taking about 4 times as
long as expected just from viscosity.
Is there any correction table available for drip measurements that can
be used to look up the measured time ratio with water, and get a good
estimate of the actual viscosity?
Thanks,
Marshall
.
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| User: "James Copeland" |
|
| Title: Re: drip viscosity measurements |
17 Sep 2005 03:40:45 PM |
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Imho, for your purpose with oils, I believe that the falling ball method
would serve you best. I discussed this technique for another person in the
sci.chem newsgroup on July 17, so you might still find it there. (It's
medium long, and I don't want to repeat it here if you can find it there.)
Jim C.
"Marshall Dudley" <mdudley@king-cart.com> wrote in message
news:432C3F62.8414BC69@king-cart.com...
I am wanting to measure the viscosity of some oils at different
temperatures and since I do not need high accuracy, was trying to use a
drip method of viscosity measurement. I took a syringe that has a long
plastic tip on it and was trying to use it. It was nice since it was
marked off in 1 cc increments up to 12 cc. This allowed me to easily
put more "head" on lighter liquids to compensate for the difference in
density. For instance for water I can fill it to the 10 cc mark and
measure the time it takes to drain out to 9 cc, and for oil that has a
density of .9, I can fill it to 11 and let it drain to 10. When I ran
some viscosity tests the results seemed to be very non-linear.
liquid expected viscosity measured time
water 1 4 seconds
diesel 2-3 8 seconds
soy oil 60-80 60 seconds
I believe that the non linearity is most likely due to the energy
necessary to accelerate the liquid through the end of the tip for the
thinner liquids is slowing it down, so water it taking about 4 times as
long as expected just from viscosity.
Is there any correction table available for drip measurements that can
be used to look up the measured time ratio with water, and get a good
estimate of the actual viscosity?
Thanks,
Marshall
.
|
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| User: "James Copeland" |
|
| Title: Re: drip viscosity measurements |
17 Sep 2005 03:44:05 PM |
|
|
Correction: it was on July 21, and the original message in the sci.chem
thread was titled: Making a Quick and Simple Viscometer. My discussion was
down the line a few messages in that thread. Hope this helps. Feel free to
contact me if I can be of further help.
Jim C.
"James Copeland" <chemcope@ksu.edu> wrote in message
news:dghv1k$pah$1@cnn.cns.ksu.edu...
Imho, for your purpose with oils, I believe that the falling ball method
would serve you best. I discussed this technique for another person in the
sci.chem newsgroup on July 17, so you might still find it there. (It's
medium long, and I don't want to repeat it here if you can find it there.)
Jim C.
"Marshall Dudley" <mdudley@king-cart.com> wrote in message
news:432C3F62.8414BC69@king-cart.com...
I am wanting to measure the viscosity of some oils at different
temperatures and since I do not need high accuracy, was trying to use a
drip method of viscosity measurement. I took a syringe that has a long
plastic tip on it and was trying to use it. It was nice since it was
marked off in 1 cc increments up to 12 cc. This allowed me to easily
put more "head" on lighter liquids to compensate for the difference in
density. For instance for water I can fill it to the 10 cc mark and
measure the time it takes to drain out to 9 cc, and for oil that has a
density of .9, I can fill it to 11 and let it drain to 10. When I ran
some viscosity tests the results seemed to be very non-linear.
liquid expected viscosity measured time
water 1 4 seconds
diesel 2-3 8 seconds
soy oil 60-80 60 seconds
I believe that the non linearity is most likely due to the energy
necessary to accelerate the liquid through the end of the tip for the
thinner liquids is slowing it down, so water it taking about 4 times as
long as expected just from viscosity.
Is there any correction table available for drip measurements that can
be used to look up the measured time ratio with water, and get a good
estimate of the actual viscosity?
Thanks,
Marshall
.
|
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| User: "Marshall Dudley" |
|
| Title: Re: drip viscosity measurements |
19 Sep 2005 12:58:56 PM |
|
|
Thanks, however I had already given up on the ball bearing method. The blasted
thing falls so fast through water I as unable to time it with a stopwatch, and
I do not have the equipment to capture it electronically with light beams. I
am concerned that if I get a plastic bead that sinks slowly in water, then the
density of the liquids will become a major factor.
Marshall
James Copeland wrote:
Imho, for your purpose with oils, I believe that the falling ball method
would serve you best. I discussed this technique for another person in the
sci.chem newsgroup on July 17, so you might still find it there. (It's
medium long, and I don't want to repeat it here if you can find it there.)
Jim C.
"Marshall Dudley" <mdudley@king-cart.com> wrote in message
news:432C3F62.8414BC69@king-cart.com...
I am wanting to measure the viscosity of some oils at different
temperatures and since I do not need high accuracy, was trying to use a
drip method of viscosity measurement. I took a syringe that has a long
plastic tip on it and was trying to use it. It was nice since it was
marked off in 1 cc increments up to 12 cc. This allowed me to easily
put more "head" on lighter liquids to compensate for the difference in
density. For instance for water I can fill it to the 10 cc mark and
measure the time it takes to drain out to 9 cc, and for oil that has a
density of .9, I can fill it to 11 and let it drain to 10. When I ran
some viscosity tests the results seemed to be very non-linear.
liquid expected viscosity measured time
water 1 4 seconds
diesel 2-3 8 seconds
soy oil 60-80 60 seconds
I believe that the non linearity is most likely due to the energy
necessary to accelerate the liquid through the end of the tip for the
thinner liquids is slowing it down, so water it taking about 4 times as
long as expected just from viscosity.
Is there any correction table available for drip measurements that can
be used to look up the measured time ratio with water, and get a good
estimate of the actual viscosity?
Thanks,
Marshall
.
|
|
|
| User: "James Copeland" |
|
| Title: Re: drip viscosity measurements |
19 Sep 2005 06:09:17 PM |
|
|
Yes, a ball bearing would fall terribly fast through water and liquids of
similar viscosity. However, since you said oils, I thought you might have a
chance at it. Depends on if the oils in question are sufficiently viscous.
Also, if you are interested only in comparative viscosities (such as the
numerical ratio of one to another) there would be negligible error so long
as you used the same ball in the same apparatus at the same temperature for
all the oils. This is because the viscosity is directly proportional to the
fall time of the ball (within reasonable error). Of course, if you want
absolute viscosity, you would need to know densities of both ball and
liquid.
Jim C.
"Marshall Dudley" <mdudley@king-cart.com> wrote in message
news:432EFC5F.4C8DB8A@king-cart.com...
Thanks, however I had already given up on the ball bearing method. The
blasted
thing falls so fast through water I as unable to time it with a stopwatch,
and
I do not have the equipment to capture it electronically with light beams.
I
am concerned that if I get a plastic bead that sinks slowly in water, then
the
density of the liquids will become a major factor.
Marshall
James Copeland wrote:
Imho, for your purpose with oils, I believe that the falling ball method
would serve you best. I discussed this technique for another person in
the
sci.chem newsgroup on July 17, so you might still find it there. (It's
medium long, and I don't want to repeat it here if you can find it
there.)
Jim C.
"Marshall Dudley" <mdudley@king-cart.com> wrote in message
news:432C3F62.8414BC69@king-cart.com...
I am wanting to measure the viscosity of some oils at different
temperatures and since I do not need high accuracy, was trying to use a
drip method of viscosity measurement. I took a syringe that has a long
plastic tip on it and was trying to use it. It was nice since it was
marked off in 1 cc increments up to 12 cc. This allowed me to easily
put more "head" on lighter liquids to compensate for the difference in
density. For instance for water I can fill it to the 10 cc mark and
measure the time it takes to drain out to 9 cc, and for oil that has a
density of .9, I can fill it to 11 and let it drain to 10. When I ran
some viscosity tests the results seemed to be very non-linear.
liquid expected viscosity measured time
water 1 4 seconds
diesel 2-3 8 seconds
soy oil 60-80 60 seconds
I believe that the non linearity is most likely due to the energy
necessary to accelerate the liquid through the end of the tip for the
thinner liquids is slowing it down, so water it taking about 4 times as
long as expected just from viscosity.
Is there any correction table available for drip measurements that can
be used to look up the measured time ratio with water, and get a good
estimate of the actual viscosity?
Thanks,
Marshall
.
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| User: "John C. Polasek" |
|
| Title: Re: drip viscosity measurements |
17 Sep 2005 12:26:19 PM |
|
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On Sat, 17 Sep 2005 12:08:03 -0400, Marshall Dudley
<mdudley@king-cart.com> wrote:
I am wanting to measure the viscosity of some oils at different
temperatures and since I do not need high accuracy, was trying to use a
drip method of viscosity measurement. I took a syringe that has a long
plastic tip on it and was trying to use it. It was nice since it was
marked off in 1 cc increments up to 12 cc. This allowed me to easily
put more "head" on lighter liquids to compensate for the difference in
density. For instance for water I can fill it to the 10 cc mark and
measure the time it takes to drain out to 9 cc, and for oil that has a
density of .9, I can fill it to 11 and let it drain to 10. When I ran
some viscosity tests the results seemed to be very non-linear.
liquid expected viscosity measured time
water 1 4 seconds
diesel 2-3 8 seconds
soy oil 60-80 60 seconds
I believe that the non linearity is most likely due to the energy
necessary to accelerate the liquid through the end of the tip for the
thinner liquids is slowing it down, so water it taking about 4 times as
long as expected just from viscosity.
Is there any correction table available for drip measurements that can
be used to look up the measured time ratio with water, and get a good
estimate of the actual viscosity?
Thanks,
Marshall
Might be surface tension. Put the merest amount of liquid soap in.
John Polasek
http://www.dualspace.net
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