In a new video which was just released, I explain thermal mass flow meter theory and working principal.
Thermal Mass Flow Working Principle
The thermal flow mass meter measures gas flow based upon the idea of convective heat transfer.
Either in-line flow bodies or insertion-style probes of the meter support two sensors that interface with the gas being measured. In the case of the Sage thermal mass meter, the sensors are resistance temperature detectors (RTDs), consisting of highly durable reference-grade platinum windings that are clad in a protective 316 SS or Hastelloy C cover.
One of the sensors is heated by an integrated circuit and functions as the flow sensor while a second sensor acts as the reference sensor, and determines the gas temperature. The Sage proprietary circuitry maintains an ongoing overheat between the flow and reference sensor. As gas flows by the heated sensor, flowing gas molecules transport heat away from the sensor and as a result, the sensor cools and the energy is lost. The circuit balance is disrupted, and the temperature difference (ΔT) between the heated RTD and the reference sensor has been altered. Within a second, the circuit restores the lost energy by heating the flow sensor, to adjust the overheat temperature.
New Video on Thermal Flow Meter Theory
Watch and listen as I explain how the electrical power required to maintain this overheat denotes the mass flow signal.
Thermal mass flow meter working principle and theory. (n.d.). Retrieved from https://sagemetering.com/blog/back-to-basics/thermal-mass-flow-meter-working-principle-and-theory/