Gas temperature meter

Abstract

Purpose: of the article is to develop a digital portable gas temperature meter in the range of -50…+600°C. To measure the temperature of dusty gas flows in the air pollution sources with the least significant digit of the digital device 1°C. Design/methodology/approach: The microprocessor measuring unit, probe and software is proposed. It leads to build a high-precision temperature meter based on a thin film sensor HM220 type "pt100". Findings: The calculation of the electrical schematic diagram parameters for signal conditioning of the sensor relative to the input range of the analog-to-digital converter. The experimental measuring unit and the probe of the gas temperature meter are assembled. The principle of the gas temperature meter calibration with the help of a precision resistance box MSR-60M is considered. The experimental gas temperature meter has a total standard uncertainty determined by type B for a maximum value of the measurement range of 1.94°C. The error of the sensor "pt100" makes the largest contribution to the total standard uncertainty, so the error increases in proportion to the value of the measured temperature. Research limitations/implications: On the basis of the proposed design of gas temperature meter it is possible to construct devices with various lengths of probes. Practical implications: The proposed meter is designed for environmental laboratories that measure the velocity, flow and sampling of dust and gas emissions from sources of air pollution. Originality/value: The device design differs due to the use of thermostable wire made of constantan as extending conductors of the temperature sensor, which is included in the unbalanced Wheatstone bridge. This solution allows the use of unipolar power supply 3.3 V for both analog and digital part of the meter. Temperature meter based on a thin film resistance thermometer is characterized by relative ease of manufacture, low material consumption, cost and high reliability.