Anyone tried this low cost oxygen flow meter?

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It takes measurements in Liters/min....how are you going to know what that translates into ppm dissolved Oxygen?
 
It won't translate to ppm. As I understand it there is no way to directly measure that for under about $1000. The next best thing is to have a repeatable process. The stuff I've read all lists oxygenation times assuming a flow rate of 1 lpm through a 0.5 micron stone, but I've never had a way to know if my flow rate was anywhere near 1 lpm. If this thing can help me keep the flow at that constant rate then at least I'll always be delivering the same amount of oxygen and I can adjust the rate over time based on the results.
 
Yeah, I ordered 2 of them. They're not perfect for the job because they're designed to measure higher flows so 1 lpm is on the very low end of the scale. That being said it was certainly better than nothing because at first it wasn't reading anything and it turns out that my cylinder was nearly empty. Then with the new cylinder it was well over 2 lpm, so there is quite a range of flows comming out of the cylinder depending on how full it is. I found it easier to regulate at 1.5 lpm and will be basing my times on that rate.
 
Yeah, I ordered 2 of them. They're not perfect for the job because they're designed to measure higher flows so 1 lpm is on the very low end of the scale. That being said it was certainly better than nothing because at first it wasn't reading anything and it turns out that my cylinder was nearly empty. Then with the new cylinder it was well over 2 lpm, so there is quite a range of flows comming out of the cylinder depending on how full it is. I found it easier to regulate at 1.5 lpm and will be basing my times on that rate.

I hope it works out for you, but keep in mind that meters tend not to read as accurately at the extremes of their range as they do the middle. So that 1 lpm, right at the low end of the range, may not be 1 lpm at all.
 
You can score actual O2 flow meters MADE to go onto standard O2 tanks on ebay in the $20-$30 range most of the time (used). New ones can run over $100-$125 though. If you get one that doesn't come with the barb fitting for the gas line (you can use the standard 3/16" beer line there) then your local welding gas supplier (same place you can get the tank) should be able to get one to work. I got two there for my flow meters, made of brass, so that they won't break when I put a clamp onto them.

The flow meters I have range up to 8 LpM of O2, which is pretty much all you need for most brewing purposes. They both start at below 1 LpM, allowing me to adjust the flow to get to where I want it to be easily.

You can also look on amazon.com for the meters.
 
You can check the accuracy by pumping the oxygen into a balloon for 1 minute and then calculating the volume of the inflated balloon.
 
You can check the accuracy by pumping the oxygen into a balloon for 1 minute and then calculating the volume of the inflated balloon.

It would be interesting to do this and compare to to what the meter says. I bet it will be off a bit (the meter)...the balloon sounds like a good way to do this (if you have a good way to accurately measure it...maybe water displacement?)
 
There's a formula to calculate the volume of a sphere. I don't know it off hand, but all you need is the radius of the inflated balloon. Make sure you use round balloons.
 
Medical O2 regulators will regulate 1-15+ Liters/min. A few quick calculations can lead you to your total wort volume in Cubic Liters, same as the O2 volume output.

The O2 Regulator's 9/2 Pin index will ONLY FIT Medical O2 bottles. You won't be able to use any old tank.
 
Medical O2 regulators will regulate 1-15+ Liters/min. A few quick calculations can lead you to your total wort volume in Cubic Liters, same as the O2 volume output.

The O2 Regulator's 9/2 Pin index will ONLY FIT Medical O2 bottles. You won't be able to use any old tank.

Ummm, hate to burst your O2 bubble there buddy, but not 100% true... You CAN get the medical regulators that fit standard O2 tanks. I have two of them.
Here's one that's still available: eBay - New & used electronics, cars, apparel, collectibles, sporting goods & more at low prices

Here's another one... Amazon.com: Drive Medical Oxygen 540 Regulators with Liter Adjustment and Various Connection Styles, Green: Industrial & Scientific I can't see what the connector is for the tubing, but it looks like (from the description) that its a threaded fitting... Not difficult to get that in a barb fitting to connect tubing to. I've done it on both of mine for CHEAP money ($0.50-$1.00 per fitting)...
 
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You could also submerge the balloon in a graduated bucket or kettle and see how much water it displaces.
 
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