Gas measuring device and method without zero calibration

Abstract

The invention relates to a gas measuring device and method. The gas measuring device comprises a measuring gas chamber and a reference gas chamber, wherein the reference gas chamber is used for encapsulating a zero-reference gas; and a circuit on the gas measuring device is symmetrically provided with sensors which correspond to the reference gas chambers. The gas measuring method comprises the step of automatically carrying out regular zero calibration by utilizing a zero-reference signal acquired by the sensor arranged corresponding to the reference gas chamber. The gas measuring device and method does not need to carry out the regular zero calibration based on an externally input zero-reference gas, thereby ensuring that the standard of gas measurement is more accurate and then ensuring the accuracy of the gas measurement.

Description

technical field [0001] The invention relates to medical electronics, in particular to a gas measuring device without zero calibration and a method thereof. Background technique [0002] At present, medical respiratory gas monitoring equipment generally uses chopping to modulate the optical path system composed of infrared light source and detector, so as to eliminate the influence of factors such as ambient temperature, light source and detector parameter changes on the measurement results during direct measurement. influences. The following takes the measurement of carbon dioxide concentration as an example. The measurement method is based on the Lambert-Beer law in spectral absorption. Since the analytical formula cannot be obtained, it is usually stored in a reference curve based on zero reference carbon dioxide concentration, and then based on real-time monitoring. Value, and look up the table according to this reference curve, and take the average calculation method to...

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Problems solved by technology

[0003] 1. Extract the air in the ambient atmosphere as the zero value of carbon dioxide. If the air carbon dioxide in the ambient atmosphere accumulates instead of zero, it will lead to a false value of the zero reference point of carbon dioxide, which will make the final measured value of respiratory carbon dioxide low;

[0004] 2. Place an adsorbent material capable of absorbing carbon dioxide at the air inlet that extracts the air in the ambient atmosphere to eliminate the possible accumulation of ambient carbon dioxide concentration, which can eliminate the problem of high zero point to a certain extent, but it also brings the possibility of this air intake The mouth is blocked due to the adsorption material. This adsorption material has a lifetime and needs to be replaced regularly, otherwise the above problems will also occur;

[0005] 3. This zero-calibration process needs to drive the strobe of the gas path of the three-way valve, and there are electrical, mechanical, and gas path conversions. Such multiple steps will also cause gas path leakage in the entire system, resulting in reliability issues. question

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