Sensing liquid levels
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Posts: 46,084
how about a optical or IR detector/emitter pair that is mounted on the
nozzle that looks through the test tube and turns off pump/solenoid when the
fluid interferes with the line of sight ?
I have also seen a proximity detector that looks for a reflection off of the
surface of the fluid
The detector and the emitter are at an angle such that at a predetermined
distance the reflection shines onto the detector. The cpu turns off valve
when it reaches proper level.
richard
Original Message
From: "Ricky Konvicka" <ricky@m...>
To: <basicstamps@yahoogroups.com>
Sent: Monday, October 15, 2001 1:08 PM
Subject: [noparse][[/noparse]basicstamps] Sensing liquid levels
> http://www.acroname.com/robotics/parts/c_Sensors.html
> Has anyone used any of the sensors from the above website to measure fluid
levels. I am building a machine to fill tubes with a hot wax type substance
and I need to sense when the tube is full. I need to do this as accurately
as possible. I want to mount the filling apparatus on an x y type plotter
and let it fill about 20 rows of tubes one at a time. But due to the
cooling nature of the liquid it takes two filling operations because the wax
shrinks and creates a cavity in the tube. So a fill of about 2/3 first,
then let cool, then top off. The first fill could probably be timed but the
second one has to be accurate because of the cap that goes on the end of the
tube. I have built a manual version that fills four tubes at a time with a
foot operated switch but this is very time consuming when you get an order
for 12,000.
>
>
> Ricky Konvicka
> Electronic Engineer
> BioTech International Inc.
> www.biotechintl.com
>
>
> [noparse][[/noparse]Non-text portions of this message have been removed]
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nozzle that looks through the test tube and turns off pump/solenoid when the
fluid interferes with the line of sight ?
I have also seen a proximity detector that looks for a reflection off of the
surface of the fluid
The detector and the emitter are at an angle such that at a predetermined
distance the reflection shines onto the detector. The cpu turns off valve
when it reaches proper level.
richard
Original Message
From: "Ricky Konvicka" <ricky@m...>
To: <basicstamps@yahoogroups.com>
Sent: Monday, October 15, 2001 1:08 PM
Subject: [noparse][[/noparse]basicstamps] Sensing liquid levels
> http://www.acroname.com/robotics/parts/c_Sensors.html
> Has anyone used any of the sensors from the above website to measure fluid
levels. I am building a machine to fill tubes with a hot wax type substance
and I need to sense when the tube is full. I need to do this as accurately
as possible. I want to mount the filling apparatus on an x y type plotter
and let it fill about 20 rows of tubes one at a time. But due to the
cooling nature of the liquid it takes two filling operations because the wax
shrinks and creates a cavity in the tube. So a fill of about 2/3 first,
then let cool, then top off. The first fill could probably be timed but the
second one has to be accurate because of the cap that goes on the end of the
tube. I have built a manual version that fills four tubes at a time with a
foot operated switch but this is very time consuming when you get an order
for 12,000.
>
>
> Ricky Konvicka
> Electronic Engineer
> BioTech International Inc.
> www.biotechintl.com
>
>
> [noparse][[/noparse]Non-text portions of this message have been removed]
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
Comments
>http://www.acroname.com/robotics/parts/c_Sensors.html
>Has anyone used any of the sensors from the above website to measure fluid
>levels. I am building a machine to fill tubes with a hot wax type
>substance and I need to sense when the tube is full. I need to do this as
>accurately as possible. I want to mount the filling apparatus on an x y
>type plotter and let it fill about 20 rows of tubes one at a time. But
>due to the cooling nature of the liquid it takes two filling operations
>because the wax shrinks and creates a cavity in the tube. So a fill of
>about 2/3 first, then let cool, then top off. The first fill could
>probably be timed but the second one has to be accurate because of the cap
>that goes on the end of the tube. I have built a manual version that
>fills four tubes at a time with a foot operated switch but this is very
>time consuming when you get an order for 12,000.
Have you considered a suck-back tube in the fill head that assures the
cylinders being filled can't be overfilled? You would fill 2/3 - 3/4 or
so, cool, then refill, overfilling and sucking back any extra. You would
control the final fill level by the depth you insert the fill head into the
tube being filled. Requires an extra pump, maybe a heater to keep the waxy
stuff molten on the return trip, but has the advantage of no real time
measurements needing to be made, no photo sensors to be confused by
splashed wax on the sidewalls, etc.
Jim H
Has anyone used any of the sensors from the above website to measure fluid
levels. I am building a machine to fill tubes with a hot wax type substance and
I need to sense when the tube is full. I need to do this as accurately as
possible. I want to mount the filling apparatus on an x y type plotter and let
it fill about 20 rows of tubes one at a time. But due to the cooling nature of
the liquid it takes two filling operations because the wax shrinks and creates a
cavity in the tube. So a fill of about 2/3 first, then let cool, then top off.
The first fill could probably be timed but the second one has to be accurate
because of the cap that goes on the end of the tube. I have built a manual
version that fills four tubes at a time with a foot operated switch but this is
very time consuming when you get an order for 12,000.
Ricky Konvicka
Electronic Engineer
BioTech International Inc.
www.biotechintl.com
[noparse][[/noparse]Non-text portions of this message have been removed]
tube won't work. I have tried some proximity type sensors but can't get the
accuracy. The top is tricky to because there is a rippling effect on the
surface as the tube is being filled. I have one sensor that shines 3 beams
down that cross. When the liquid rises to where the 3 beams cross it
triggers the sensor, but the rippling effect gives false readings.
Original Message
From: Richard Friedrich <rfriedrich@a...>
To: <basicstamps@yahoogroups.com>
Sent: Monday, October 15, 2001 9:13 AM
Subject: Re: [noparse][[/noparse]basicstamps] Sensing liquid levels
> how about a optical or IR detector/emitter pair that is mounted on the
> nozzle that looks through the test tube and turns off pump/solenoid when
the
> fluid interferes with the line of sight ?
>
> I have also seen a proximity detector that looks for a reflection off of
the
> surface of the fluid
> The detector and the emitter are at an angle such that at a predetermined
> distance the reflection shines onto the detector. The cpu turns off valve
> when it reaches proper level.
>
> richard
>
>
>
>
>
Original Message
> From: "Ricky Konvicka" <ricky@m...>
> To: <basicstamps@yahoogroups.com>
> Sent: Monday, October 15, 2001 1:08 PM
> Subject: [noparse][[/noparse]basicstamps] Sensing liquid levels
>
>
> > http://www.acroname.com/robotics/parts/c_Sensors.html
> > Has anyone used any of the sensors from the above website to measure
fluid
> levels. I am building a machine to fill tubes with a hot wax type
substance
> and I need to sense when the tube is full. I need to do this as
accurately
> as possible. I want to mount the filling apparatus on an x y type plotter
> and let it fill about 20 rows of tubes one at a time. But due to the
> cooling nature of the liquid it takes two filling operations because the
wax
> shrinks and creates a cavity in the tube. So a fill of about 2/3 first,
> then let cool, then top off. The first fill could probably be timed but
the
> second one has to be accurate because of the cap that goes on the end of
the
> tube. I have built a manual version that fills four tubes at a time with
a
> foot operated switch but this is very time consuming when you get an order
> for 12,000.
> >
> >
> > Ricky Konvicka
> > Electronic Engineer
> > BioTech International Inc.
> > www.biotechintl.com
> >
> >
> > [noparse][[/noparse]Non-text portions of this message have been removed]
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed. Text in the Subject
and
> Body of the message will be ignored.
> >
> >
> > Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
> >
> >
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
>
units (134105) will give you an accuracy in millimeters. Commercial
units are reliable but expensive (around $200 by the time you put
everything in). You can also build one very easy. Check the
Parallax book for project. Also check Scott Edwards book "
Programming and Customizing the Basic Stamp" for complete example
and code to make a simple U-sound measuring device using a Stamp.
Al
--- In basicstamps@y..., "Ricky Konvicka" <ricky@m...> wrote:
> http://www.acroname.com/robotics/parts/c_Sensors.html
> Has anyone used any of the sensors from the above website to
measure fluid levels. I am building a machine to fill tubes with a
hot wax type substance and I need to sense when the tube is full. I
need to do this as accurately as possible. I want to mount the
filling apparatus on an x y type plotter and let it fill about 20
rows of tubes one at a time. But due to the cooling nature of the
liquid it takes two filling operations because the wax shrinks and
creates a cavity in the tube. So a fill of about 2/3 first, then
let cool, then top off. The first fill could probably be timed but
the second one has to be accurate because of the cap that goes on
the end of the tube. I have built a manual version that fills four
tubes at a time with a foot operated switch but this is very time
consuming when you get an order for 12,000.
>
>
> Ricky Konvicka
> Electronic Engineer
> BioTech International Inc.
> www.biotechintl.com
>
>
> [noparse][[/noparse]Non-text portions of this message have been removed]