CN-121994754-A - High-temperature-resistant diffuse reflection gas measuring device based on optical waveguide

CN121994754ACN 121994754 ACN121994754 ACN 121994754ACN-121994754-A

Abstract

The application discloses a high-temperature-resistant diffuse reflection gas measuring device based on an optical waveguide, which comprises a diffuse reflection sheet, a first convex lens, an optical waveguide, an antireflection film optical window, a second convex lens, a collimator and a photoelectric detector, wherein the diffuse reflection sheet and the first convex lens are fixedly arranged at one end of the optical waveguide and form a TDLAS air chamber, the antireflection film optical window, the second convex lens, the collimator and the photoelectric detector are fixedly arranged at the other end of the optical waveguide, the antireflection film optical window is fixedly arranged at the end surface of the optical waveguide, an opening is arranged in the middle of the second convex lens, the beam output end of the collimator passes through the second convex lens from the opening, the beam input end of the collimator is connected with an output optical fiber of the TDLAS laser, and the photoelectric detector is positioned at the beam input end of the collimator. The high-temperature-resistant diffuse reflection gas measuring device based on the optical waveguide can stably measure gas for a long time under the environmental working conditions of high temperature, corrosion, water vapor condensation and the like, and has the advantages of simple structure and low cost.

Inventors

WEI ZHANFENG
ZHOU XIAOCHUN
CHANG YANG
ZHANG JUN

Assignees

北京光感慧智科技有限公司

Dates

Publication Date: 20260508
Application Date: 20251219

Claims (8)

1. The high-temperature-resistant diffuse reflection gas measuring device based on the optical waveguide is characterized by comprising a diffuse reflection sheet, a first convex lens, the optical waveguide, an antireflection film optical window, a second convex lens, a collimator and a photoelectric detector, wherein the optical waveguide is made of high-temperature-resistant materials, the diffuse reflection sheet and the first convex lens are fixedly arranged at one end of the optical waveguide, the first convex lens is close to the optical waveguide, the diffuse reflection sheet is far away from the optical waveguide, a certain distance exists between the first convex lens and the diffuse reflection sheet and forms a TDLAS air chamber, the antireflection film optical window, the second convex lens, the collimator and the photoelectric detector are fixedly arranged at the other end of the optical waveguide, the antireflection film optical window is fixedly arranged at the end face of the optical waveguide, an opening is arranged in the middle of the second convex lens, the beam output end of the collimator passes through the second convex lens from the opening, the beam input end of the collimator is connected with the output optical fiber of the TDLAS laser, and the photoelectric detector is positioned at the collimator input end of the collimator and has a certain distance.
2. The optical waveguide-based high temperature resistant diffuse reflection gas measurement device of claim 1, wherein the optical waveguide is a quartz optical waveguide.
3. The optical waveguide-based high temperature resistant diffuse reflection gas measuring device of claim 1, wherein the optical waveguide has a length of at least 0.6m.
4. The optical waveguide-based high temperature resistant diffuse reflection gas measurement device of claim 1, wherein the diameter of the antireflection film optical window is 1.5 times the diameter of the collimated beam.
5. The high temperature resistant diffuse reflection gas measuring device based on optical waveguide according to claim 1, wherein the antireflection film optical window is adhered to the end face of the optical waveguide by transparent glue with refractive index of 1.45.
6. The optical waveguide-based high temperature resistant diffuse reflection gas measuring device according to claim 1, wherein the diffuse reflection sheet is made of a metal material or a glass material.
7. The optical waveguide-based high temperature resistant diffuse reflection gas measurement device according to claim 1, further comprising a collimator fine adjustment fixing structure comprising a fixed adjustment structure and a fixed structure, wherein the collimator is disposed in the fixed adjustment structure and the fixed structure, is fixed by a fixing screw, and is adjusted by an adjusting screw.
8. The optical waveguide-based high temperature resistant diffuse reflection gas measurement device of claim 1, further comprising a flange that is sleeved and circumferentially fixed to an axial middle portion of the optical waveguide.

Description

High-temperature-resistant diffuse reflection gas measuring device based on optical waveguide Technical Field The application relates to the technical field of gas measurement, in particular to a high-temperature-resistant diffuse reflection gas measurement device based on an optical waveguide. Background A TDLAS (Tunable Diode Laser Absorption Spectroscopy ) laser gas sensor is a high-precision gas detection device based on the principle of spectral absorption. The air chamber of the TDLAS laser gas sensor is composed of an optical lens. The gas chamber is used for transmitting laser in the laser to the gas chamber, converting the laser into a light beam transmitted in space, irradiating the light beam into an atmosphere to be detected, if the atmosphere to be detected contains gas to be detected, the gas can absorb energy with corresponding wavelength in the laser, outputting the light beam to the photoelectric detector through the gas chamber, analyzing a light intensity signal of the laser light beam, judging the intensity of an absorption curve, and calculating the concentration of the gas by inversion. However, the traditional air chamber has poor tolerance, is limited by the reliability of temperature resistance, corrosion resistance and steam resistance of glue for fixing the air chamber structure, can not be bonded when glue materials deform or glue is carbonized at high temperature, and is limited by the temperature deformation of the air chamber fixing structure, for example, 316L stainless steel is adopted in the general industrial field, and the deformation amount is large under the high-low temperature change, so that the optical coupling can be damaged, and signals can not return to a detector. In practical application, the air chamber is placed in the environment to be measured. If the measurement is performed in the industrial field, most of the air chambers are subjected to environments such as high temperature, corrosion, water vapor condensation and the like, so that the measuring working conditions of the air chambers are poor. To solve the problem, the application in the industrial field of TDLAS generally adopts a pair of holes formed in an industrial pipeline and two optical observation windows are arranged, a TDLAS optical path is designed to pass through one optical observation window, and a detector is arranged on the other side to form a TDLAS measuring air chamber. Because the increased optical observation window is in contact with the outside, and the outside temperature is lower than the temperature in the pipeline, high-temperature water vapor in the pipeline can form condensed water on the observation window when encountering cold. In order to solve the problem of water vapor condensation, a heat tracing structure is also required to be added, so that the system structure is complex. In addition, the heat tracing structure requires pipeline punching for installation, and the accuracy of punching must be ensured, so that production is stopped when punching is performed. If adjustment is needed, the machine also has to be stopped for maintenance. In order to treat condensed water and pollutants, heating and purging functions are added on the light window, so that additional equipment is increased, the cost is increased, and the reliability is reduced. In summary, the two existing schemes can not meet the long-term, stable and low-cost measurement of the TDLAS gas sensor under severe working conditions. Disclosure of Invention Therefore, the application provides a high-temperature-resistant diffuse reflection gas measuring device based on an optical waveguide, which aims to solve the problem that a TDLAS gas sensor in the prior art cannot stably measure gas for a long time under the environment working conditions of high temperature, corrosion and water vapor condensation. In order to achieve the above object, the present application provides the following technical solutions: The high-temperature-resistant diffuse reflection gas measuring device based on the optical waveguide comprises a diffuse reflection sheet, a first convex lens, the optical waveguide, an antireflection film optical window, a second convex lens, a collimator and a photoelectric detector, wherein the optical waveguide is made of high-temperature-resistant materials, the diffuse reflection sheet and the first convex lens are fixedly arranged at one end of the optical waveguide, the first convex lens is close to the optical waveguide, the diffuse reflection sheet is far away from the optical waveguide, a certain distance exists between the first convex lens and the diffuse reflection sheet and forms a TDLAS air chamber, the antireflection film optical window, the second convex lens, the collimator and the photoelectric detector are fixedly arranged at the other end of the optical waveguide, the antireflection film optical window is fixedly arranged at the end face of the optical waveguide, an opening is forme