Device and method for mixing fuel gas and combustion air, hot water installation provided with it, corresponding mass flow thermal sensor and method for measuring a mass flow of a gas flow

摘要

A device for mixing combustible gas and combustion air, hot water installation, and corresponding thermal mass flow sensor and method. The device includes an air line, a gas line with a control valve, a first measuring line connecting the air and gas lines, and a second measuring line connecting the first measuring line to the gas and/or air line, forming a three-way intersection. A thermal mass flow sensor includes first and second temperature sensors in the first measuring line, positioned respectively in a gas flow between the three-way intersection and the air line and in a gas flow between the three-way intersection and the gas line. A controller controls the control valve based on a difference, measured by the flow sensor, between mass flow rate of gas between the three-way intersection and the air line and mass flow rate of gas between the three-way intersection and the gas line.