# Calculating volume of bottle of water.

1. Jul 29, 2012

### Paws!

Can a venturi be used to calculate the flow rate of water out of a 1000ml bottle of water to determine an arbitrary volume left within the bottle?

I need to calculate arbitrary volumes of water within opaque bottles of >1000ml without removing or coming into contact with the solution.

I need to calculate results electronically so was thinking of using sensors of a venturi of a way of achieving this.
Anybody have any advice, or a solution?

Thanks.

P.s: This is an independent study, not academic.

2. Jul 29, 2012

### Danger

Welcome to PF, Paws!.
My approach would be to weight the thing, but I don't know whether or not that meets your requirements.

3. Jul 29, 2012

### Paws!

I have considered that, I'm just not sure how sensitive it would be to changes of around 10ml at a time, and also how accurately I could determine the exact volume remaining in the bottle.

4. Jul 29, 2012

### Danger

I guess that it depends upon your resources. For the 20 years that I tended bar, I had to do a visual inventory. I actually bought a postal scale to make the job easier, but my boss wouldn't let me use it. (I took the price of it out of the till, though, because she told me ahead of time that I could use one.) The other main bar in town has a really nice electronic scale that plugs into the bar computer. It's accurate to less than a quarter-gram, and the software is programmed with the specific gravities of just about any liquor available on the planet. For instance, 350 grams of Kahlua will show a different volume on the display than will 350 grams of vodka.
If you can find and/or afford a system like that, and have it calibrated to whatever fluid you're using, it could save you some hassle. The system here, back when I was in the business, cost about $2,500, so that's a definite drawback. My postal scale, on the other hand, cost$40 and was accurate to about 1/2 gram. Whether or not that coincides with your 10ml requirement depends upon the density of your fluid.
There are far more sensitive digital (mine was mechanical) scales available, but I don't know what they cost.
If your fluid is dense enough that you don't need a highly accurate measurement, maybe seek out a diabetic friend and ask to use his/her food scale. They're good to within a couple of grams. (I was diabetic for about 30 years, and had to weigh everything that I ate. Jeez, but I'm glad that I discovered beer and gave up on all of that noise.)

5. Jul 29, 2012

### Paws!

Thanks, that maybe useful. Could you point me in the direction of such a system.

P!

6. Jul 29, 2012

### Danger

I'll snoop around a bit. Where do you live? (You don't have to be precise, but at least divulge what country you're in.) I'm in western Canada, so it's not likely that our markets overlap.

7. Jul 30, 2012

### Paws!

I'm based in London, uk.

8. Jul 30, 2012

### Staff: Mentor

9. Jul 30, 2012