Pumps and Meters??
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Hello - I am trying to tinker with an industrial control type application
which will deliver a calibrated amount of liquid over and over again.
Does anyone know of any low cost pumps which are pretty accurate that
could be hooked to a basic stamp to deliver bursts of a liquid to a catch
basin? The device would need to be pretty accurate and the volume of
product delivered will not be constant all the time, but the pump should
be able to deliver a repeatable volume of liquid for periods of time.
If no-one knows of a pump, do you know of any electronic fluid flow
metering devices which can be used with non-corrosive liquids such that
the device could be placed in-line with a fluid supply and, in
combination with a stamp, could "shut off" the stream once an amount of
liquid has been delivered?
Both of the above would need to be relatively low cost.
This is my first experience with playing with digital electronics - I am
a computer scientist by nature, so the programming part is easy - but if
we need to get into detailed electronics lingo - take it easy on me [noparse]:)[/noparse]
Bob.
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which will deliver a calibrated amount of liquid over and over again.
Does anyone know of any low cost pumps which are pretty accurate that
could be hooked to a basic stamp to deliver bursts of a liquid to a catch
basin? The device would need to be pretty accurate and the volume of
product delivered will not be constant all the time, but the pump should
be able to deliver a repeatable volume of liquid for periods of time.
If no-one knows of a pump, do you know of any electronic fluid flow
metering devices which can be used with non-corrosive liquids such that
the device could be placed in-line with a fluid supply and, in
combination with a stamp, could "shut off" the stream once an amount of
liquid has been delivered?
Both of the above would need to be relatively low cost.
This is my first experience with playing with digital electronics - I am
a computer scientist by nature, so the programming part is easy - but if
we need to get into detailed electronics lingo - take it easy on me [noparse]:)[/noparse]
Bob.
________________________________________________________________
YOU'RE PAYING TOO MUCH FOR THE INTERNET!
Juno now offers FREE Internet Access!
Try it today - there's no risk! For your FREE software, visit:
http://dl.www.juno.com/get/tagj.
Comments
>which will deliver a calibrated amount of liquid over and over again.
>
>Does anyone know of any low cost pumps which are pretty accurate that
>could be hooked to a basic stamp to deliver bursts of a liquid to a catch
I don't know about 'low cost', but we use a chemical injection pump to feed
the cooling towers for large commercial chillers. The length of the piston
pump stroke is adjustable to change the anount of feed, as well as the length
of time that the pump runs. Newer pumps are lighter, all plastic and *should*
cost less. Check with NALCO or MITCO chemical.
what are your accuracy requirements?
I built a device a few years back for dispensing 100 to 1,000 millileters
of de-ionoized
water for a chemical extraction setup. The poor soul using the machine had
over twenty thousand to do.
It was accurate to better than 0.5% and cost about $100 in parts
Steve
At 06:40 PM 09/26/2000 -0400, you wrote:
>>Hello - I am trying to tinker with an industrial control type application
>>which will deliver a calibrated amount of liquid over and over again.
>>
>>Does anyone know of any low cost pumps which are pretty accurate that
>>could be hooked to a basic stamp to deliver bursts of a liquid to a catch
>
>I don't know about 'low cost', but we use a chemical injection pump to feed
>the cooling towers for large commercial chillers. The length of the piston
>pump stroke is adjustable to change the anount of feed, as well as the
length
>of time that the pump runs. Newer pumps are lighter, all plastic and
*should*
>cost less. Check with NALCO or MITCO chemical.
>
>
>
>
> what type of volumes are you needing?
>
> what are your accuracy requirements?
>
> I built a device a few years back for dispensing 100 to 1,000
> millileters
> of de-ionoized
> water for a chemical extraction setup. The poor soul using the
> machine had
> over twenty thousand to do.
>
> It was accurate to better than 0.5% and cost about $100 in parts
>
> Steve
I am looking to deliver volumes from 6cc's to 40cc's in volume (6mL to
40mL's) with a decent accuracy (+/- 1-2% would be best)
I'd be interested in hearing your solution, regardless of whether or not
it meets my requirements.
Bob.
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>Hello - I am trying to tinker with an industrial control type application
>which will deliver a calibrated amount of liquid over and over again.
>
>Does anyone know of any low cost pumps which are pretty accurate that
>could be hooked to a basic stamp to deliver bursts of a liquid to a catch
>basin? The device would need to be pretty accurate and the volume of
>product delivered will not be constant all the time, but the pump should
>be able to deliver a repeatable volume of liquid for periods of time.
>
>
>
>Hi Bob,
Web offset presses use these devices. Try that.
Svata (Steve)
http://skalicka.8k.com
Try a bellows pump, we've used these for our automatic titration machines,
this would be perfect for your application.
http://www.gripumps.com/
Hope this helps,
David
Robert Smith wrote:
> On Tue, 26 Sep 2000 19:54:34 -0500 sargent@s... writes:
> > what type of volumes are you needing?
> >
> > what are your accuracy requirements?
> >
> > I built a device a few years back for dispensing 100 to 1,000
> > millileters
> > of de-ionoized
> > water for a chemical extraction setup. The poor soul using the
> > machine had
> > over twenty thousand to do.
> >
> > It was accurate to better than 0.5% and cost about $100 in parts
> >
> > Steve
>
> I am looking to deliver volumes from 6cc's to 40cc's in volume (6mL to
> 40mL's) with a decent accuracy (+/- 1-2% would be best)
>
> I'd be interested in hearing your solution, regardless of whether or not
> it meets my requirements.
>
> Bob.
>
> ________________________________________________________________
> YOU'RE PAYING TOO MUCH FOR THE INTERNET!
> Juno now offers FREE Internet Access!
> Try it today - there's no risk! For your FREE software, visit:
> http://dl.www.juno.com/get/tagj.
I'll try to explain it the best I can, it's been a few years since I worked
with it, but the accuracy it delivered was alot better than I could have
expected.
I'm sure many on this list understand the principles at work here better
than I, so please
bear with me.
The heart of the design was based around a mariotte siphon. I filled a
large sealable container with water and inserted a mariotte tube. I hose
was then connected from the spigot of the container to a remote ball valve
(made by spraying systems). An adjustable timer was set up so that when i
pushed a small button, it opened the valve for a certain period of time,
adjustable by a potentiometer, and then closed it. by adjusting the time it
was open would change the volume delivered. The mariotte siphon in the
water container tricked the water pressure into staying relatively
constant, even as the container was drained. I built this in 1992, and
often think of the neat things i could do with it now with a stamp.
It seemed like a dumb idea, surely the time between when the ball valve
opened to when it closed would not be very uniform, but it was awfully good.
The system was used to dispense 1,000 ml volumes over 25,000 times without
any trouble.
I expected the ball valve to wear out, but it never did.
When I had the system fine tuned, I would come to expect the device to
deliver 1,000 ml
plus or minus 3 or 4 ml, or + - .4%. I'm sure this could be improved if i
used a stamp to monitor the actual water pressure and apply a correction as
the container drained.
I located a link which explains the mariotte tube principle,
http://www.uswcl.ars.ag.gov/events/exper/mariotte.htm
hope someone finds this interesting,
/Steve
At 12:06 AM 09/27/2000 -0400, you wrote:
>
>
>On Tue, 26 Sep 2000 19:54:34 -0500 sargent@s... writes:
>> what type of volumes are you needing?
>>
>> what are your accuracy requirements?
>>
>> I built a device a few years back for dispensing 100 to 1,000
>> millileters
>> of de-ionoized
>> water for a chemical extraction setup. The poor soul using the
>> machine had
>> over twenty thousand to do.
>>
>> It was accurate to better than 0.5% and cost about $100 in parts
>>
>> Steve
>
>I am looking to deliver volumes from 6cc's to 40cc's in volume (6mL to
>40mL's) with a decent accuracy (+/- 1-2% would be best)
>
>I'd be interested in hearing your solution, regardless of whether or not
>it meets my requirements.
>
>Bob.
>
>________________________________________________________________
>YOU'RE PAYING TOO MUCH FOR THE INTERNET!
>Juno now offers FREE Internet Access!
>Try it today - there's no risk! For your FREE software, visit:
>http://dl.www.juno.com/get/tagj.
>
>
>
Interesting post....never heard of a mariotte tube.... printed the posting
and am pondering the physics as I type this message.
Thanks,
Ray McArthur
> I located a link which explains the mariotte tube principle,
>
> http://www.uswcl.ars.ag.gov/events/exper/mariotte.htm
>
> hope someone finds this interesting,
>
> /Steve