Thanks for the information. We just got 3 brand new flow controllers without really knowing how to use them. We are just following the instruction manuals. I'm trying to explain to my coworkers that you have to FLOW the gas. You can just stopper it into a chamber and say DONE. We want only a small amount to generate small bubbles in liquid. But we don't need a bubble bath, we need a few bubbles. So i'm suggesting we mix our gasses and then sample FROM the gas stream. I think it's best for us.

This channel is literally better than an undergraduate degree

Thank you for learning me something better then I had known before hand. Love your stuff no matter what you call your channel, always informative and interesting to boot.

Always enjoy your well done videos with clear explanations. The pleasure of a good class/lab lecture without the commute and cranky professor..LOL Thanks!

holy cow i now understand why and how to calibrate a mass flow controller for a given gas, probably for deeper engineering behind it one has to change RTD (resistive temperature detector) for the given gas

At 1:56, that is just one of the ways to measure gas flow. Another very interesting way to measure gas flow is using the coriolis force. By having a tube that goes in a square, and exciting this structure with a current in a magnetic field (lorentz force), we can observe the motion this makes. By now having a flow through that hollow tube, this movement will change due to the coriolis force, which is caused by the mass flow. This is of course all a MEMS. The advantage of this method is that you can measure far more accurately how much the mass flow is. You can also measure other things like viscosity. A downside is that it has an upper limit to how much massflow it can actually measure, in contrary to the heater/thermocouple measurement. That is why companies like bronckhorst often combine both of these sensor types to achieve a higher dynamic range of massflow.

Gets me thinking of variometers - instruments glider pilots use to measure their ascent rate in rising air. I had a simple pellet gauge/ flask vario in the 70's but I suspect modern electronic versions use something like this.

I used a anemometer for air flow measurements. It used a heater and a thermocouple down stream. That's basically what your device does. So I guess that was really a mass flow measurement device. they are designed to be inserted in air ducts.

oh your changed your channel name. i like it.

That was some useful explanation. Thanks and well done!!

Always something interesting to show, I see. Thanks. Am I understanding the way it works correctly. At 2:37ish the coils are providing the heat and the temperature sensing is being done my measuring the temperatures of the coils? That makes sense in regard to your temperature profiles since the incoming gas would take more heat from the first coil than the second coil, since the greater the temperature difference the more efficient the heat transfer. The gas is still cool at the first coil so there's more efficient heat transfer and so the coil gives up more heat making that coil cooler. When the gas gets to the second coil, the gas is heated so there's a smaller temperature difference and so a less efficient heat transfer. The second coil therefore doesn't give up as much heat and remains hotter.

Not a bad explanation. I own a company that has calibrated, repaired and sold MFC's for 37 years.

Last time i disassembled flow meter, it had Analog Blackfin DSP :) (we use it in our lab, for HHG generation)

this dude is my nigga

Nice video, like all your videos!

Great video as always Ben

norxcontacts I'm curious to know why you don't like the channel name, and what sort of name you'd prefer.

Hey what? Applied Science? Ben Krasnow was getting immortal soon.

Very curious about how the proportional valve works? Is it just a needle valve balanced between a spring and the coil current?

The biggest and common problem of MFC is when the the capilairy tube clodged, sadly I never know how to clean it up.

Hi, I'm a bit confused... You said that 12 psi is about 2 atm, but from another source I get that 1 psi is about 0.068 atm, and consequently 12 psi is about 0.816 atm. Am I missing something?

youre a really smart. i always like your videos!

I like the name change.

These things are great, nice explanation too. Do you know what temperature do the coils get up to in yours?

High Valued Stuff. thanks as always;

very old UNIT elastomer, (rubber seals) MFC. solenoid valve is very hard to stably set... valve must be stable. 10 cc very hard to accurately set to specification.

Well done sir!

As far as I know the LM324 isn't the best of OP-AMPs. It's very basic and it is the component that needs the +/-15V supply,

good stuff, as always...

A new username can be confusing, but nice video as always.

Nice video, In the real world though, those instruments are not calibrated with the specific gas (i.e. the one that the user will measure). Some manufacturers like Bronkhorst, Brooks and Sierra Instruments deliver instruments for all gases which were factory-calibrated only with air (or N2). They provide the user with a K-Factor whose exactitude has not been proven. Some other companies like Horiba-STEC do not even use K-factors but Polynomial correction curves. K-factors give errors…. Another point, and not the least of them, These traditional meters like the capillary principle are a metal tube that gets heated, as a consequence these units drift over time and need to be calibrated and of course adjusted at least once per year. An alternative is to use mass flow meters/controllers with MEMS sensors technology which, conversely, are always factory-calibrated with the "real gas" so to obtain the best possible accuracy. These units are extremely stable, with clean gas they can stay stable for more than 10 years.

The inlet and outlet connection of that mass control is called VCR. You will have a leak if you connect gas tubing that way. Here is the 1/4 female VCR to 1/4 tube adapter. m.ebay.com/itm/321787470755

I have an idea for your next project, build an Einstein refrigerator! Never seen one in operation or heard any specs!

Thanks for the video. used mfc for a long time without knowing how it works! I have a question: we know it works well for gaseous content (N2, O2, Ar). How will it work for vapors (ethanol, water, acetone vapors generated from the vaporized liquids)? I was looking at how to introduce weird gases into my chamber. Do share some wisdom if u have :P

Applied Science What is the actuator for the valve and the valve type/mechanism? Also, did you measure, or find out from specs what the change time (to within 5 or 10% or something) is to stabilize/steady-state from a given set point to another? Also as a side note, you should probably enunciate the A sound more because it sounds like you're saying roto meter. I also prefer the pronunciation "rotam eter" because it sounds less weird, although it is preference and I think both are OK.

Which kind of electronic circuits you use can you send the circuit details???

I like Ben Krasnow better... it Branding of his specific style and class of video... What storm causes the change?

i like the older channel name better..

Would a combination of automotive sensors be precise enough for your purposes...?

I am trying to understand if it is possible to build digitally controlled system that could cycle a propane/oxygen surface mix burner on for a set amount of time and then back off again. I am designing a robot that will be controlled by Pololu Maestro Servo Controller. This will control multiple servos that will primarily power gear racks for linear movement. An element of the robot is the flame that I am hoping I can also control with the Pololu Maestro as well. Is it possible to turn oxygen and propane lines on and off with a solenoid valve and somehow have the mass flow controllers located after the solenoids to deliver the precise flow I am looking for? Or do the mass flow controllers have to be manually turned on and off for each cycle. Sorry for all of the questions. I'm just starting on this project and after many hours of searching, watching, reading I have no idea where to turn for answers. The linear movement aspect of the robot is quite simple but understanding how to or even if I can cycle the flame on and off precisely still eludes me. Do you have any suggestions? Thanks for any help you can provide.

Thanks for your video! But could you please help me with this problem. We have the same system in our brewery. And the thing is that the Rotameter shows 17 Nm3/h and the mass flow shows 22 kg/h. When i do the conversion, it seems not correct. The rotameter is calibrated at 6 bar 20 deg. C and our supply air is at 5.5 bar and 30 deg .C. I check the density of air at that condition should be 6.32 kg/m3, but it seems like they are programmed at standard condition with the density of air is ~ 1.2 kg/m3.

Greeting; Can you please release the name of the gas mass flow controllers (both electromagnetic & manual) as well the software use to control & reading them. Thanks a lot

Is something similar used in IC engines with Electronic control?

I am interested in making a MFC work to control some gases in an experiment. Can you tell me the wiring you used to make your mfc work?

How much power input the mass flow meter requires to measure the flow?

Could you use a fan? the energy generated by it would be the flow.

0 - 5 vdc valve drive circuit, 0 - 5 vdc sensor circuit...

I just realized that you go through infinity times more argon per month than almost every other person on Earth. What's that like? How does it feel? What's your monthly argon budget?

Wouldn't the rotometer read accurately on the output side of the mass flow controller?

...ever heard of Forrest Mims?

Am I missing something or is 12 PSI not even 1 atmosphere ?

what SCCM range are they?

Oh... you changed the channel name. Had me confused. "I didn't subscribe to a channel of this name."

Why do you need to do this? ha! I'm just asking.....what is you line of work that you get to "play" in you lab all day??!?!?!?

I think it's time for u Ben to have 2 or 3 kids...don't u love kids? U can explain all this to them :)

Dig ur chnl......subbbbbz. Do stuff on lasers pleaseeeee. Chrys on top

Some of his information is correct but I hope he is not in the mass flow business because he has NO idea what he is talking about! That pot that is exposed with a hole in cover is the zero pot.

Ben I'm a fan, but "applied science" sucks.