Thermal Flow Meter for Condensing Gas Environments
2 Comments


Kurz instruments manufactures thermal
mass flow meters for dry and wet gas applications. A probe with two temperature sensors is inserted
into the process flow. One sensor provides the process
reference temperature. The other sensor is heated to a
constant temperature above the process flow. Gas molecules strike the heated
sensor and draw away heat. To compensate for the heat loss
additional power is directed to the heated sensor to keep the constant temperature differential. The speed of the flow and the type of gas determines the
amount of energy sent to the sensor. The amount of energy used to maintain
the differential temperature reflects the mass flow rate. Wet gas is found in digester and landfill
environments. It contains mostly methane carbon
dioxide and water vapor. Daily and seasonal
cooling fluctuations commonly reduce the wet gas temperature
causing the water vapor to condense into a heavy fog. The water droplets contacting the heated
sensor draw much more energy than dry gas molecules. The extra energy use to compensate for
this cause a false high reading. Long
cooling periods result in large water droplets forming in the biogas flow, causing water to collect on and drip
down the pipe walls. Sensors that have a low overheat are
unable to vaporize all the water in larger drops. The excess
water spreads across the heated sensor and causes spikes and poor readings.
Depending on the overheat it can take up to 30 minutes for a
thermal meter to recover from a large water impact. The Kurz WGF is the solution for
monitoring wet gas flows. The heated sensor operates at 300
degrees Celsius above the process temperature, instantly
vaporizing any water on contact. With this
super-heated sensor, the vaporization energy becomes a small
portion of the available signal, so the flow reading is relatively
unaffected by the water. The vaporized water also creates a
momentary cushion around the super-heated sensor that
diverts water around the sensor. This natural barrier allows the WGF
to maintain a high signal-to-noise ratio and provide accurate and repeatable
readings. Kurz instruments provides the innovative solutions for the challenges
in biogas applications.

2 thoughts on “Thermal Flow Meter for Condensing Gas Environments

  1. Traditional thermal flow meters cannot function properly in a wet gas environment. The Kurz 454FTB-WGF is not a traditional thermal flow meter…

  2. dear Kruz

    do you have something accurate to measure a very low velocities and volume in huge lines such as flare lines
    example:
    50000 scfd at 36" line

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