Today, the operating volumetric flow rate has been obtained many industrial flow measurement applications for compressible fluids:
This requires additional measurements of pressure and temperature to calculate the
mass flow rate. These corrective measures and compansations add cost and increase the complexity of the
measurements; in addition they decrease the measuring system accuracy. The thermal
mass flow measurement for gases, on the contrary, provides mass flow rate in kg/h directly
without any additional measurements or calculations. Using the normal density
of the gas the normal volume flow rate can be calculated, e.g. in Nm³/h.
There are two industrial methods used for thermal gas mass flow rate measurement,
hot film anemometers and calorimetric or capillary meters.
Advantages:
– Direct gas mass flow measurement
– No pressure and temperature compensation required
– Very low pressure drop
– High measuring accuracy
– Large span
– No moving parts
– Rugged construction
– Short response time
– Easily sterilized
Limitations:
– For gases only
– Inlet and outlet sections required
Typical Applications
• Gas flow measurements in the chemical and process industries
• Compressed air balancing
• Gas burner control
• Digester gas and aeration measurements in sewage treatment plants
• Gas measurements in air separation systems
• Hydrogen measurements in processes
• Carbonization in breweries and soft drink production