A gaseous substance detection device based on transparent capillary structure and fluorescence

Abstract

The invention discloses a gaseous substance detection device based on a transparent capillary structure and fluorescence, comprising a light source system arranged on a capillary base, a fluorescent coating capillary, and a detection system, and the detection system and the light source system are perpendicular to the wall of the fluorescent coating capillary The detection system and the light source system are set at 90 degrees. The light source system includes an LED light source, a collimation system, and a first optical filter connected in sequence. The detection system includes a detector and a second optical filter. The light source and the detector of the present invention are arranged at 90 degrees along the wall of the fluorescent coating capillary tube, avoiding the direct irradiation of the excitation light on the detector, the optical path is short, and the influence of water vapor is reduced, and the second filter is isolated from the gas path and will not be affected Gas pollution; the setting of the casing can reduce the stray light of the excitation light, enhance the fluorescence intensity and signal intensity; reduce the background noise of the signal, and reduce the influence of water vapor and dust adhesion in the detection gas.

Description

technical field [0001] The invention relates to a gas detection device, in particular to a gaseous substance detection device based on a transparent capillary structure and fluorescence. Background technique [0002] The gaseous substance detection and analysis technology using the intensity change of the coating fluorescence on the inner wall of the capillary is an effective detection and analysis technology for trace substances. At present, the devices using this technology usually have two forms. One is to coat the inner wall of the capillary The light source hits the coating on the inner wall to produce fluorescence. The light source and detector are placed on both sides of the capillary relative to each other. The filter on the light source side filters out the part of the excitation light that overlaps with the fluorescence wavelength, and the filter on the detector side Select the wavelength band of interest in fluorescence, filter out the excitation light, and the ga...

AI Technical Summary

Problems solved by technology

The problem with this structure is that the light source and the detector are placed face to face, and the excitation light emitted by the light source also directly irradiates the filter on the detector side, and then passes through the attenuation of the filter on the detector side and is received by the detector. arrive

The excitation light received by the detector is an invalid signal, superimposed on the effective fluorescence, resulting in an increase in the background output of the detector, resulting in an increase in output bias and background noise

[0003] Another structural form is that the light source is set on one side of the capillary wall, and the detector is set at the gas outlet end of the capillary, that is, the detector is placed on the end gas channel of the capillary, and the fluorescence is transmitted to the end of the capillary through the waveguide effect of the capillary, and then Received by the detector, the detector is not in the irradiation area of ​​the excitation light under this structure, so the interference caused by the excitation light can be largely suppressed. However, this structure has the following problems: the fluorescence needs to pass total reflection in the capillary wall Transmission, therefore, in the part where the fluorescence is generated and the light is emitted from the end, any adhesion phenomenon on the inner and outer walls (such as water vapor attached to the inner wall) will affect the total reflection, and the structure of placing the detector at the end lengthens the distance of light transmission in the glass wall , if the total reflection at any point in this long optical path is destroyed, the light transmission will be disturbed, resulting in abnormal changes in the output of the detector

In addition, the filter on the detector side is exposed to the gas path, and the adhesion of dust and water vapor will also cause abnormal changes in output

Both of these changes can lead to detection failure, and the latter can also cause filter failure, causing machine failure

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