A Miniature Thermal Conductivity Gas Sensor

Abstract

The invention relates to a miniature heat conduction gas sensor, which comprises: a lower cover and an upper cover airtightly bonded to the lower cover, wherein, the upper surface of the lower cover is provided with: two oppositely arranged pads and two suspended hot wire assemblies respectively connected to the two pads and arranged opposite to each other; the lower surface of the upper cover is provided with: two groups of first shallow groove air passages connected in sequence, gas diffusion chamber and the second shallow groove air channel, wherein the two gas diffusion chambers correspond to the positions of the two hot wire assemblies respectively, and each gas diffusion chamber is provided with an isolation structure protruding downward from the upper cover. The invention avoids the flowing gas directly blowing the hot wire, so that the whole micro-thermal conductivity gas sensor is insensitive to the flow rate, thereby effectively reducing the noise generated by the fluctuation of the flow rate of the gas path without the need for subsequent compensation calculations, thereby achieving high High performance, extremely low power consumption, and extremely small size thermal conductivity gas sensor.

Description

technical field [0001] The invention relates to a gas sensor, in particular to a miniature heat conduction gas sensor which realizes gas concentration detection based on the difference of gas thermal conductivity. Background technique [0002] The thermal conductivity detector (Thermal Conductivity Detector, TCD) is a non-destructive, physical and universal detector, which realizes gas concentration detection by measuring the difference in thermal conductivity between the measured component and the carrier gas. The principle of operation, basic theory and response characteristics of thermal conductivity detectors were well established in the 1960s. It basically responds to all gaseous substances, and has the advantages of simple structure, reliable performance, accurate quantification, low price and durability. Since the thermal conductivity detector is non-destructive, it can also be used in conjunction with other detectors. Therefore, thermal conductivity detectors are a...

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Problems solved by technology

According to the above gas heat conduction formula, the shallow groove is more sensitive to the change of gas concentration than the deep groove, but the response of the two hot wires to the gas flow rate is equivalent. Although the μ-TCD can reduce the fluctuation noise of the gas flow rate through subsequent compensation, time consuming

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