On-wall in-tube inserted thermal flexible micro sensors for measuring mass-flow

A new thermal mass flow micro sensor that uses polyimide film as the substrate material and thermal insulation has been developed. The working principle of thermal micro sensors is the calorimetric method, using Au as the resistance material. We describe a new inner wall surface-mounted structure. This design can decrease power consumption and improve measurement accuracy. The TCR value of the heater is 0.0026 K^-1, and a response time of less than 0.4 μs.