Affected by medium type. Constant power thermal mass flow meter measurement will not affected by medium wet or dirty. But for constant temperature difference type to keep the constant temperature difference and fast response time of temperature, the RTD is made a thin type. The scavenged will on the probe after long operating in wet or dirty medium measurement and this scavenged will affected RTD heat dissipation! Finally the accuracy will be lower. The constant power type have been polished and can keep high accuracy in the long-term.
Temperature compensation difference. Constant temperature difference do not have the compensation for temperature loss. As we know the value of thermal mass and equilibrium constant changes with the change of temperature and temperature of medium will affected by many factors to keep constant. Constant power type thermal mass flow meters capable of automatic compensation for temperature variations over a wide range
The temperature changes in constant power type will not have compensation, but constant temperature
High temperature tolerance; Constant power type max high temperature is 454°C（849.2°F）, and constant temperature difference type is max high temperature is 260°C(500°F).
In conclusion, the constant power thermal mass flow meter will have significant
advantages than constant temperature type in mostly fluids measured fields.