Mechanical sealing type minitype thermal conductivity detector

Abstract

The invention relates to a mechanical sealing type minitype thermal conductivity detector and belongs to the field of microelectronics mechanical systems. An organic glass cover plate slotted at the center is fixedly connected with a bolt of an organic glass base, a silica gel spacer, a glass sheet, a rubber seal ring and a silicon substrate between the organic glass cover plate and the organic glass base are compressed and integrated to form a gas passage and a minitype thermal conductivity cell of the thermal conductivity detector, and the heat loss of a thermistor is maximally reduced through the design of a back air cavity, an air cavity formed by large and small rubber rings, and a suspended thin-layer silicon nitride support layer. Meanwhile, the comb-structure staggered arrangementmode of the thermistors in the single thermal conductivity cell guarantees the consistency of the temperatures of the thermistors on diagonal arms of a bridge; and the bolt connecting and sealing avoids the high-temperature high-pressure bonding process. Therefore, on the basis of low power consumption and high-accuracy performance of the design of the minitype thermal conductivity detector, the processing craft is simplified, the stability and the firmness are improved, the processing cost is effectively saved, and the economic benefit is increased.

Description

technical field [0001] The invention relates to the field of micro-electro-mechanical systems, in particular to the design of a mechanically sealed miniature thermal conductivity detector, which can be widely used in the analysis of various binary and multi-component gas mixtures. Background technique [0002] The thermal conductivity detector is widely used in the field of gas analysis as an independent sensor element or a gas chromatograph tail-end detector. It uses the difference in thermal conductivity of different gases to make the mixed gas with different volume fractions pass through the thermal conductivity detector. The resistance is used to detect the integral fraction of the mixed gas according to the steady-state temperature achieved by the thermistor. Thermal conductivity detectors are widely used as general-purpose detectors due to their simple setup, low cost, and their response to almost all gases. [0003] The thermal conductivity detection method is the ea...

AI Technical Summary

Problems solved by technology

[0004] 1. In the current design of micro-thermal conductivity detectors, the complexity of the micro-machining process is insufficiently considered, and the design is more ideal, especially for the bonding steps involved in the process. There is no good solution. Most of them will remove the insulating layer on the bonding surface for bonding before the bonding step, but there is still no good way to deal with the electrode leads, which requires multi-step photolithography and etching processes to solve the problem, which makes the cost rise rapidly and is economical. Poor sex

[0005] 2. In the current design of miniature thermal conductivity detectors, it is often used as an auxiliary detector, but if it is used as an independent gas sensor, its stability and robustness are slightly insufficient, and it is easier to damage , especially the design of some cantilever beams has greatly increased the process complexity and vulnerability in the case of limited sensitivity improvement

In addition, in the previous design, the two thermistors in a single thermal conductivity cell were arranged in the upstream and downstream of the air flow direction in turn, which made the heat dissipation of the two thermistors different, making it difficult to ensure temperature consistency and affecting the measurement accuracy

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