The HUALIU Thermal Gas Mass Flowmeter (model HL-RSL) is a gas mass flow measuring instrument based on the thermal dispersion principle. Two standard-grade platinum resistance thermometers (RTDs) are built into the sensor: one serves as a constant-temperature heat source, the other measures the fluid temperature. As gas flows past, the heat dissipation varies with flow rate, and the temperature difference between the two RTDs is linearly related to the flow rate; microelectronic control technology then converts this into a linear flow signal output. Because mass flow is measured directly, stable and reliable results are obtained without additional temperature or pressure compensation.

The product offers outstanding advantages: a wide turndown ratio (100:1), high sensitivity to low flows in large diameters, resistance to on-site pipeline vibration, and short upstream and downstream straight-run requirements. A proprietary "dual-balanced structure" encapsulates the sensor and, combined with high-temperature, high-humidity algorithms, allows medium temperatures up to 300℃, enabling simultaneous flow and temperature detection with switchable display, together with multi-point non-linear curve correction and bidirectional detection. The instrument is available in insertion-type and in-line installation forms, with integral or remote structures, and outputs covering 4~20mA, RS485/RS232 (MODBUS RTU), HART and pulse/frequency signals. Flameproof and SIL2 certification options are available, and installation and maintenance are simple.

With its wide range of applicable diameters and flow velocities, the HUALIU Thermal Gas Mass Flowmeter is widely used in the utilities, oil and gas, power, chemical, metallurgical, paper, food and pharmaceutical, and environmental protection industries, for the metering and monitoring of compressed air, natural gas, biogas, coal gas, flue gas, hydrogen, nitrogen and various corrosive gases.