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Thread: Looking for a flow meter...

  1. #31
    Join Date
    Mar 2009
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    CT
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    361
    Quote Originally Posted by Roland Jacques View Post
    I believe you can factor out temp differences and even factor out water vapor using a modified bottle testing.

    If you fill your 1 litter bottle with your HHO gas from your cell. then disconnect the hose. let that bottle stand for a few hours. the gas temp will become room temp (which 70 degrees should be our standard) AND the vapor will condensate out of it's gas state. then measure the contents. from this...
    I agree a standard is needed, this would cut out some of the bullsh*t in this field.

  2. #32
    Join Date
    Aug 2008
    Location
    Southern Alberta Canada
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    483
    Quote Originally Posted by HHO BLASTER View Post
    I agree a standard is needed, this would cut out some of the bullsh*t in this field.
    I thought this calc adjusts for temp - http://site.altpropulsion.com/MMWCalc.htm
    Come to the Darkside - We have Cookies
    And lots of KOH (16 LBS)

    Not currently running HHO.
    I dont run HHO during winter.

  3. #33
    Join Date
    Aug 2008
    Location
    GA
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    1,079
    Quote Originally Posted by mytoyotasucks View Post
    I thought this calc adjusts for temp - http://site.altpropulsion.com/MMWCalc.htm
    Hmm interesting, that calculator shows temp having virtually no impact It seems that there is some discrepancies, that calculator does not jive with the gas laws... or at least the way i understand them.

  4. #34
    Join Date
    Jun 2009
    Location
    Fort Worth, TX
    Posts
    510
    I know a semiconductor company, FreeScale, makes some electronic sensors that measure air pressure. These sensors have a connection for tubing to be attached.

    What I have in mind, is making a digital flow sensor using these pressure sensors. How do you measure flow with pressure? Simple - well, relatively... If you have the HHO gas going into a small compartment with a tiny hole drilled in it, the pressure inside this compartment will be higher as more HHO gas flows into it. This is analogous to Ohms law in electronics - the voltage across a resistor is proportional to the current through it. If the gas flow were current, and the pressure were voltage, this would be very similiar.

    Granted, the flow/pressure relationship is somewhat nonlinear, but this IS a digital sensor, so if it were interfaced with something like my Digital HHO Controller, calculations could easily be made to determine the correct flow rate. Hey, there's another feature... HHO Production metering!

  5. #35
    Join Date
    Oct 2008
    Posts
    126
    Make one, very easy to do....


  6. #36
    Join Date
    Jul 2009
    Location
    Australia
    Posts
    23

    flow meter

    Hi Dodge,
    Thats great thanks very much.
    Llew

  7. #37
    There has been much debate about various methods used to measure the gas output of our electrolizers. For affordability I still favor the variable area meters for many reasons which I have previously stated, most prevalent being real-time measurement. I have also stated that the float method, having its inherent inaccuracies is still a good method for the home experimenter to use for relative measurements to deduce possible cell design improvements. However it is a totally unacceptable method for a seller of electrolyzers to use to claim cell performance. Posted here are pictures of our latest gas measurement instrument, The Alicat M Series Digital / Analog Mass Flow Meter. http://www.alicatscientific.com/prod...flow-meter.php As you can read on their website this meter is pressure and temperature compensated, measures 31 different gases, ect. Several IHHOI members are now using Alicats and we see it as our reference standard for measuring cell performance. I’m looking into developing procedures to verify the calibration of VA meters as referenced to the Alicat. FYI an Alicat able to measure to 20 LPM with HHO calibration can be had for slightly over $1000.00, for a few hundred dollars more you can purchase software to interface it to your computer. The pictured Alicat originally measured to 50 LPM, however having a turndown ratio of 100:1, I wanted the guaranteed accuracy on the low end to be at 300mlm instead of 500mlm so I had it recalibrated (certification number 0000038814) to measure a max of 30 LPM. I fabricated the battery bracket to afford portability, enabling field testing of installs unable to enter the lab. Once again in my opinion, using compensation for gas temperature, for convenience, real-time measurement, and affordability, a variable area flow meter with calibration for HHO is heads above anything floating in water. If you can afford ten to twelve+ times the cost, by all means call Alicat Scientific, talk to Jesse, and order one for yourself, you won’t regret it. Last Saturday, just for grins and my own edification, I ran around collecting materials and built a eudiometer patterned after the one built and displayed on youtube by Lutherp40, with a couple of my own design changes. Many kudos to Luther for all his excellent work, I do recommend to anyone wishing to step up from the "bottle in a bucket", build one of these, this is a slick tool for relative measurement. On the flow bench I have a "B3" from "Hydrogen Junkie" (OUTSTANDING cell). I ran it at at about 8 amps and the eudiometer took 43 seconds to register 500ml. Rounded that's .698LPM. Immediately switching to the Alicat (affectionately having been coined the disappoint meter by Spodie Odie) and read on the Mass flow scale .500LPM. You don't have to be Einstein to see that as an industry we should not, no, can not, endorse floating anything as a method to verify advertised performance claims. It's also real easy to see how so many people can arrive at completely erroneous MMW numbers.
    "EXPERIENCE" it's what you get when you don't get what you want!

  8. #38

    Unhappy

    I must post a retraction. During my conversation with Spodie tonight, I was corrected, he let me know that he does not call the Alicat the disappoint meter, he in fact refers to it as the depressometer. (depress-O-meter)
    "EXPERIENCE" it's what you get when you don't get what you want!

  9. #39
    Join Date
    Aug 2008
    Location
    GA
    Posts
    1,079
    Most "High tech flow meters" measure the velocity and density ... of the gases and then try to determine a volume from that, some types can be WAY off & some are spot on
    The bottle measures the actual volume.
    If the pump at a gasoline station (a velocity type flow meter) says it gave you 5 gallons of gasoline, yet your gas can (actual volume) only reads 4.5 gallons which one will you think is right?

    If you really want to make your bottle/eudiometer testing accurate.
    1. Let that gas stand for 1 hour, become a ambient 75 degree room temperature. Measure the gas shrinkage, and now you can factor that percent of shrinkage into your calculations of you future tests of that cell.
    2. Let the steam condensate now the accuracy is even better.
    3. And if you really want go to better accuracy, Then factor in your atmospheric pressure. http://www.turblex.com/altitude/index.cfm but even Denver’s -2 psi makes little difference
    4.To improve time accuracy run you test repeatedly and take a average. A bigger bottles helps time accuracy also.

    IMO. Sellers should always ALSO use the bottle method when advertising. If 95% of us use it It really is the standard. To use any other in advertising makes it impossible to hold sellers accountable. Seller can claim anything when they have the excuses, “We have the Triple X-Caliber flow meter and according to it we are right.” I’ve seen 34 MMW claims by sellers, and they say they use the best flow meter available so… Then you get it, and measure 4 MMW with the bottle method. Then they tell you the bottle method is wrong…

    Gas law calculator
    http://www.1728.com/combined.htm

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