Design Challenge : accurately measure several liquids in a container

It has been a while since my last Design Challenge to the community, but it's time to get back into the groove and working the prefrontal cortex. Innovation is spurred through creative thinking, so give it a shot even if you don't reply.

Similar to one I proposed in the past, Measuring liquid inside a closed container, but now you can put anything you want into the container. But it isn't that easy. I want to measure two different liquids that a present in the container, water and oil.

Here are the requirements:

1. Monitor a container that is between 10-15 feet tall and 10 feet in diameter

2. Report the whole volume of liquid in the container

3. Report the amount of water, or water level

4. Report how much total oil is present

5. Constantly measure changes

6. Report back with an accuracy of about a 1/10th of a gallon. (or as accurate as possible)

I have a few ideas, but I don't want to contaminate early ideas with my own.

There is not right or wrong answer, so give it a shot.

Cabe

Check out some other challenges:

Design Challenge : relay spike protection

Design Challenge : The Amateur Fireworks Show

Thought Experiment; Detecting Distance

0 gordonmx over 14 years ago

If the container is a cylinder with a fixed diameter, you can meaure the thickness of each layer of liquid (assuming they seperate), but to be within 1/10th of a gallon accuracy would mean you must be able to accurately a measure thickness of ~.001" for water and know the density of the oil. At a radius of 5', a gallon of water only has a thickness of .02".
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0 Catwell over 14 years ago in reply to gordonmx

Gordon,

That is the challenge. To make it easier, let's say the container is over 3/4 of the way filled, but the amounts of the various liquids is not set.

Thoughts?

Cabe
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0 Former Member over 14 years ago

Put it in a container with a clear section, put a measure up the side and once the liquids have settled read off the values?
Done and dusted
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0 Catwell over 14 years ago in reply to Former Member

Tom,

That is really not an option. The container is too large, and the contents of the container change quite regularly. I want to monitor the vat 24/7 with constant precision. And hiring a guy to "eyeball" the levels seems like it may lead to inaccurate results.

Have any other ideas from an EDE viewpoint?

Cabe
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0 Lotfi_G over 14 years ago

A possible solution could be the measurment of resistivity change using a vertically inserted small electrodes from the top of the container (controlled by a motorised system allowing a fine control and measurment of the level of insertion of the electrodes within the container).
We will notice a resistivity change when crossing interfaces between air, liquid1 and liquid 2.

An enhancement of this solution could be to use a laser telemeter from the top to measure height of the the two liquids togheter.... when this level changes we control the electrodes system at the interface between liquid 1 and liquid 2 so that we avoid that the electrodes system be continiously moving up down and down up for real time measurments. It just needs to be moved to monitor the liquids interface height change.

Lotfi
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0 Catwell over 14 years ago in reply to Lotfi_G

Lotfi,

I like the laser solution, less moving parts. If the laser was turned on from the top, how would you measure the lower liquids level? Would there be two bounceback signals from the various liquids?

And if the top liquid is dense oil, the laser may not penetrate enough to bounce back from the second level.

Is ultrasonic an option?

Cabe
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