The FMM 504 series of thermal gas mass flow meters are instruments that measure the mass flow of gases using the principle of heat transfer.
The meter’s sensor consists of two reference-level thermal resistors (platinum RTD). One is the mass velocity sensor T1, and the other is the temperature sensor T2 that measures the temperature change of the gas. When the two RTDs are placed in the gas to be measured, the sensor T1 is heated to a constant temperature difference above the gas temperature, and the other sensor T2 Used to sense the temperature of the gas being measured. As the gas mass flow rate increases, the airflow takes more heat, and the temperature of the sensor T1 decreases. To maintain a constant temperature difference between T1 and T2, the heating power of T1 increases. According to the law of Kin’s law of thermal effect, the heating power P, the temperature difference ΔT (T1-T2) and the mass flow rate Q have a certain mathematical relationship.
