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Density Measurement in 3051SMV Multivariable Transmitter


I would like to know that for a Natural Gas application, how a 3051SMV Multivariable transmitter can measure the density? I could not find a way to feed the live gas composition to this transmitter, then why it is marketed as a a fully compensated mass flow transmitter that can consider all the factors in the AGA 3 flow equation including density?



1 Reply

  • Hi Shaig,

    The 3051SMV measures static pressure, differential pressure and process temperature. None of these measured variables can be used separately or in combination to determine process fluid composition. They can, however, be used to determine the density of a known fluid with an established relationship between compressibility and density. With regard to natural gas, this relationship is established through AGA which assumes a gas composition as part of the known variables going into the calculation for gas compressibility and density. Basically, the transmitter does not physically measure the density of the fluid, rather it uses the measured variables mentioned above to calculate a fluid density given the user selected process fluid (Natural Gas composition) that is imported into the transmitter using Engineering Assistant Software.

    Thank you,
    Michael Flesch