Design of refrigerated micro-flow thermal mass flow controller

Abstract

The article addresses the problems of low linearity, poor reliability, and susceptibility to environmental and other factors in the measurement of small flow rates by liquid mass flow meters in industry and designs a refrigeration-type thermal mass flow controller without making the device large-scale. Adopting a microprocessor and pt1000 temperature sensor, the semiconductor refrigeration sheet utilizing the Peltier effect makes the temperature difference of the flowing liquid so as to measure the liquid mass flow rate by obtaining the temperature data and analyzing the data in order to achieve the function of flow rate measurement, so as to realize the purpose of flow rate measurement and control. By keeping the heating element and the measured fluid temperature difference constant after constant power work, measuring the fluid temperature after heat transfer, and finally detecting the voltage connected to the platinum resistor to react to the fluid flow. After preliminary testing in non-extreme environments, it is proved that the system has the characteristics of low cost and low power consumption, which is of reference value for the development and application of embedded systems and provides an effective method for the measurement of micro-flow liquids.