CN220104855U - Detector for gas detection - Google Patents

Abstract

The utility model provides a detector for gas detection, which comprises a tube seat, a tube cap, a photoelectric detector chip and a reflecting piece group, wherein the tube cap is fixed on the tube seat and encloses a closed cavity with the tube seat, a light window is arranged on the tube cap, the photoelectric detector chip and the reflecting piece group are arranged in the cavity, the cavity is filled with detected gas, and light beams enter the cavity from the light window and then are projected onto the reflecting piece group, and are reflected by the reflecting piece group and then are projected onto the photoelectric detector chip. The utility model can improve the optical path of the detector for gas detection so as to improve the resolution of the detector.

Description

Detector for gas detection

Technical Field

The utility model relates to the technical field of gas component detection, in particular to a detector for gas detection.

Background

The TDLAS (Tunable Diode LaserAbsorption Spectroscopy) technology is based on a tunable diode laser, and utilizes the characteristic of frequency selection of measured gas molecules to realize the measurement of the measured gas characteristics. The method successfully avoids the interference of other gas components and becomes the optimization of the scheme of the current accurate real-time online gas detection system. Meanwhile, the method has the advantages of high corresponding speed and low measurement lower limit, and can simultaneously analyze various gas components, mainly including methane, carbon monoxide, carbon dioxide, oxygen, ammonia, ethylene, acetylene and other gases. Therefore, in the late nineties, gas detection schemes and devices based on TDLAS technology have emerged as spring shoots, and various measurement modes such as fixed test systems, distributed test systems, portable test systems, and telemetry test systems have appeared in the field of industrial application.

To achieve high accuracy measurements, it is necessary to ensure that the center wavelength of the laser operation in the laser system is exactly aligned with the absorption wavelength of the gas being measured. However, the driving current of the laser, the ambient temperature and other factors can cause the wavelength drift of the laser, so that the detector with the reference air chamber is inoculated. However, current detectors with reference gas cells suffer from the following disadvantages: the volume is large, the optical path is short, and according to Beer-Lambert Law (Beer-Lambert Law), the optical path and the gas absorption intensity are positively correlated, so that the shorter the optical path is, the lower the resolution of the reference gas chamber detector is, and the lower the accuracy of the laser wavelength calibration is.

Therefore, there is a need for improvement of the existing gas detection probes to increase the resolution of the gas detection probes, thereby increasing the detection accuracy of the gas.

Disclosure of Invention

The utility model aims to provide a detector for gas detection, which aims to solve the problem of low resolution of the existing detector for gas detection.

In order to solve the technical problems, the utility model provides a detector for gas detection, which comprises a tube seat, a tube cap and a photoelectric detector chip, and further comprises a reflecting piece group, wherein the tube cap is fixed on the tube seat and encloses a closed cavity with the tube seat, a light window is arranged on the tube cap, the photoelectric detector chip and the reflecting piece group are arranged in the cavity, the cavity is filled with detected gas, and light beams are projected onto the reflecting piece group after entering the cavity from the light window, reflected by the reflecting piece group and then projected onto the photoelectric detector chip.

Optionally, the reflecting member group includes a first reflecting member and a second reflecting member, and the light beam enters the cavity from the light window and then is projected onto the first reflecting member, reflected by the first reflecting member and then is projected onto the second reflecting member, and reflected by the second reflecting member and then is projected onto the photodetector chip.

Optionally, the photodetector chip and the first reflecting member are respectively fixed on the upper surface of the tube seat, the tube cap is provided with the optical window, and the second reflecting member is fixed on the optical window on the inner side of the tube cap.

Optionally, the photodetector chip and the first reflecting member are respectively disposed on two sides of the central axis of the tube socket.

Optionally, an included angle between the first reflecting piece and the upper surface of the tube seat is greater than or equal to 1 °.

Optionally, the second reflecting member is disposed in parallel with a surface opposite to the upper surface of the stem.

Optionally, the first reflecting piece includes first speculum and base, the base is right trapezoid or right triangle's boss or right trapezoid or right triangle's recess of cross-section, first speculum sets up on the inclined plane of boss or set up on the inclined plane of recess, the second reflecting piece is the second speculum.

Optionally, the first reflecting piece includes reflection seat and first high reflectivity coating film layer, the reflection seat sets up on the upper surface of tube socket, the reflection seat is right trapezoid or right triangle's boss or right trapezoid or right triangle's recess for the cross-section, first high reflectivity coating film layer sets up on the inclined plane of boss or set up on the inclined plane of recess, the second reflecting piece is including setting up the second high reflectivity coating film layer on the light window of tube cap inner wall.

Optionally, the tube seat and the reflection seat are integrally formed.

Optionally, a header pin is further included, and the header pin passes through the header and is electrically connected with the photodetector chip.

The detector for gas detection provided by the utility model has the following beneficial effects:

firstly, because the reflecting piece group is arranged in the cavity, the pipe cap is provided with the light window, the cavity is filled with the detected gas, and the light beam enters the cavity from the light window and then is projected onto the reflecting piece group, and is projected onto the photoelectric detector chip after being reflected by the reflecting piece group, the original direct light can be changed into reflection type through the reflection of the reflecting piece group, the optical path of the light beam is increased, the absorption intensity of the gas to the light intensity of specific wavelength is greatly improved in a limited space, the absorption depth and the amplitude of the modulated light intensity received by the photoelectric detector chip in the gas detection system circuit of the detector are deeper, and the wavelength of the semiconductor laser is fed back to an algorithm to be adjusted more accurately and constantly, and the resolution and the detection precision of the detector for gas detection are improved.

In addition, because the pipe cap is fixed on the pipe seat and encloses a closed cavity with the pipe seat, and the photoelectric detector chip is arranged in the cavity, compared with the direct-injection type long-optical-path reference air chamber detector in the current market, the volume of the detector in the embodiment is tighter, and the requirements of portable and telemetering products with small sizes are met more easily.

In addition, the detected gas filled in the space surrounded by the tube seat and the tube cap of the detector is dry detected gas with low dew point temperature, and the dew point temperature is less than or equal to 0 ℃. Therefore, the situation that the system misjudges the center wavelength is caused by the fact that water gas in the gas is separated out and light path and light intensity change caused by the fact that the gas to be detected is adhered to the surface of an optical element due to the fact that the temperature of the gas to be detected is too low can be effectively avoided, and the applicability of the low-temperature environment of the product can be improved.

In addition, as the reflecting piece group is arranged, the light beam is not vertically incident to the photosensitive surface of the photoelectric detector chip, and the reflected light cannot return to the emergent laser along the original light path, so that unstable and nonlinear output power and mode-jump phenomenon of the laser caused by the reflected light are avoided, and meanwhile, the reflected light in the optical link is reduced, so that the noise of the optical link is reduced.

Drawings

FIG. 1 is a cross-sectional view of a gas detection probe according to a first embodiment of the present utility model;

FIG. 2 is a schematic view of an optical path of a gas detection probe according to a first embodiment of the present utility model;

FIG. 3 is a cross-sectional view of a gas detection probe according to a second embodiment of the present utility model;

fig. 4 is a schematic optical path diagram of a gas detection probe according to a second embodiment of the present utility model.

Reference numerals illustrate:

100-tube seats; 200-pipe cap; 300-a photodetector chip; 400-chamber; 500-light window; 510-an antireflection film layer; 600-a first reflector; 610-a first mirror; 620-a base; 630-a reflection base; 640-a first high-reflectivity coating layer; 700-a second reflector; 710-a second high reflectivity coating; 800-tube base pins; 900-measured gas.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present utility model more apparent, the technical solutions of the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model, and it is apparent that the described embodiments are some embodiments of the present utility model, but not all embodiments of the present utility model. The components of the embodiments of the present utility model generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the utility model, as presented in the figures, is not intended to limit the scope of the utility model, as claimed, but is merely representative of selected embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.

In the description of the present utility model, it should be noted that, directions or positional relationships indicated by terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., are directions or positional relationships based on those shown in the drawings, or are directions or positional relationships conventionally put in use of the inventive product, are merely for convenience of describing the present utility model and simplifying the description, and are not indicative or implying that the apparatus or element to be referred to must have a specific direction, be constructed and operated in a specific direction, and thus should not be construed as limiting the present utility model. Furthermore, the terms "first," "second," "third," and the like are used merely to distinguish between descriptions and should not be construed as indicating or implying relative importance.

Furthermore, the terms "horizontal," "vertical," and the like do not denote a requirement that the component be absolutely horizontal or overhang, but rather may be slightly inclined. As "horizontal" merely means that its direction is more horizontal than "vertical", and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.

In the description of the present utility model, it should also be noted that, unless explicitly specified and limited otherwise, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present utility model will be understood in specific cases by those of ordinary skill in the art.

Embodiment 1,

Referring to fig. 1 and 2, fig. 1 is a cross-sectional view of a gas detection probe according to a first embodiment of the present utility model, and fig. 2 is a schematic view of an optical path of the gas detection probe according to the first embodiment of the present utility model, where the gas detection probe includes a socket 100, a cap 200, a photodetector chip 300, and a reflector group, the cap 200 is fixed on the socket 100 and encloses a closed chamber 400 with the socket 100, the cap 200 is provided with an optical window 500, the photodetector chip 300 and the reflector group are disposed in the chamber 400, the chamber 400 is filled with a gas 900 to be detected, and a light beam is projected onto the reflector group after entering the chamber 400 from the optical window 500, reflected by the reflector group, and then projected onto the photodetector chip 300.

Because the reflecting piece group is arranged in the cavity 400, the light window 500 is arranged on the pipe cap 200, the cavity 400 is filled with the detected gas 900, and the light beam enters the cavity 400 from the light window 500 and then is projected onto the reflecting piece group, and is reflected by the reflecting piece group and then is projected onto the photoelectric detector chip 300, the original direct type can be changed into the reflective type through the reflection of the reflecting piece group, the light path of the light beam is increased, the absorption intensity of the gas to the light intensity with specific wavelength is greatly improved in a limited space, the absorption depth of the modulated light intensity received by the photoelectric detector chip 300 in the gas detection system circuit of the detector is larger, and the wavelength of the semiconductor laser is fed back to the algorithm to be adjusted more accurately and constantly, so that the resolution and the detection precision of the detector for gas detection are improved; in addition, since the pipe cap 200 is fixed on the pipe seat 100 and encloses a closed cavity 400 with the pipe seat 100, and the photo-detector chip 300 is disposed in the cavity 400, compared with the direct-injection long-optical-path reference air chamber detector in the current market, the volume of the detector in the embodiment is tighter, and the requirements of portable and telemetering products with small size are more easily met; in addition, since the reflecting member group is provided, the light beam is not vertically incident to the photosensitive surface of the photodetector chip 300, and the reflected light cannot return to the outgoing laser along the original light path, so that unstable and nonlinear output power and mode-jump phenomenon of the laser caused by the reflected light are avoided, and meanwhile, the reflected light in the optical link is reduced, so that the noise of the optical link is reduced.

Referring to fig. 1 and 2, the reflector group includes a first reflector 600 and a second reflector 700, and the light beam is projected onto the first reflector 600 after entering the cavity 400 from the light window 500, is projected onto the second reflector 700 after being reflected by the first reflector 600, and is projected onto the photodetector chip 300 after being reflected by the second reflector 700. Thus, the optical path in the chamber 400 has a zigzag shape, or an N-shape. In one embodiment, the reflector assembly may further include a third reflector, such that the optical path within the chamber 400 is M-shaped. In another embodiment, the reflector group may further include a third reflector and a fourth reflector, so that multi-stage reflection may be formed in the chamber 400 to increase the optical path length. Of course, in other embodiments, the reflector assembly may include other reflectors, such that multiple reflections may be formed to increase the optical path, and the utility model is not limited to a particular number of reflectors.

Referring to fig. 1 and 2, specifically, the photodetector chip 300 and the first reflecting member 600 are respectively fixed on the upper surface of the stem 100, the cap 200 is provided with an optical window 500, and the second reflecting member 700 is fixed on the inner side of the optical window 500 on the cap 200.

Referring to fig. 1 and 2, the photodetector chip 300 and the first reflecting member 600 are disposed on both sides of the central axis of the stem 100, respectively.

Referring to fig. 1 and 2, the first reflecting member 600 forms an angle of 1 ° or more with the upper surface of the stem 100. Thus, the light beam is not vertically incident to the photosensitive surface of the photodetector chip 300, and the reflected light cannot return to the outgoing laser along the original light path, so that unstable output power, nonlinearity and mode-jump phenomenon of the laser caused by the reflected light are avoided, and meanwhile, the reflected light in the optical link is reduced, so that the noise of the optical link is reduced.

Preferably, the angle between the first reflecting member 600 and the upper surface of the stem 100 is 17 °.

The second reflecting member 700 is disposed in parallel with the upper surface of the stem 100.

The first reflecting member 600 includes a first reflecting mirror 610 and a base 620, the base 620 is a boss with a right trapezoid cross section, the first reflecting mirror 610 is disposed on an inclined plane of the boss, and the second reflecting member 700 is a second reflecting mirror. In other embodiments, the base 620 is a groove with a right trapezoid cross section, and the first reflecting mirror is disposed on an inclined plane of the groove.

In this embodiment, the stem 100 is integrally formed with the base 620.

The gas detection probe further includes a socket pin 800, and the socket pin 800 is electrically connected to the photodetector chip 300 through the socket 100.

The gas filled in the chamber 400 may be a dry measured gas 900 having a low dew point temperature. The dew point temperature is less than or equal to 0 ℃. The situation that the system misjudges the center wavelength is caused by light path and light intensity change caused by the fact that water gas in the internal gas is separated out and attached to the surface of an optical element due to the fact that the environmental temperature of the internally filled measured gas 900 is too low is effectively avoided, and the applicability of the low-temperature environment of the product can be improved.

The preparation method of the detector for gas detection in this embodiment is as follows:

in step S100, the photodetector chip 300 is fixed on the upper surface of the socket 100 provided with the 2pin socket pin 800, and is positioned on one side of the axis of the socket 100, and the distance from the axis is 1.72mm.

In step S200, the first reflector 600 is fixed on the upper surface of the stem 100, and is located at the other side of the axial center of the stem 100, and the distance from the axial center is 0.8mm.

In step S300, the positive and negative electrodes of the photodetector chip 300 are electrically connected to the header pins 800.

In step S400, the second reflecting member 700 is fixed to the inner surface of the light window 500 in the cap 200, and covers only half of the circular light window 500. A part of the semicircular window of the circular light window 500 is transparent to light beams in a plan view, and the other part of the semicircular window is blocked by the second reflecting member 700.

Step S500: the stem 100 including the photodetector chip 300 and the first reflector 600 is coaxially aligned with the cap 200 including the second reflector 700, and after rotating the cap 200 to the same side of the second reflector within the cap 200 as the photodetector chip 300 on the stem 100, it is placed into a sealing machine of the measured atmosphere.

Step S600: and (5) placing the pre-aligned tube seat 100 and tube cap 200 into a sealing machine in the measured atmosphere environment for airtight sealing welding, and completing assembly and sealing.

The optical path of the gas detection probe in this embodiment is as shown in fig. 2: the external incident light beam is perpendicular to the tube holder 100, passes through the light window 500, and then passes through the first reflecting member 600, the second reflecting member 700, and finally is reflected to the photosensitive surface of the photodetector chip 300, and is transmitted to form a reflective reference detector light path. The light path is Z-shaped or N-shaped.

At this time, the relative angle of the incident beam with respect to the first reflecting element 600 is 107 °, the light passes through the first reflecting element 600, the second reflecting element 700 in turn according to the principle of total reflection, and finally the beam is incident on the photosensitive surface of the photodetector chip 300 at an angle of 34 ° with respect to the photodetector chip 300. The position distance of the photodetector chip 300 with respect to the central axis of the header 100 is the final offset distance after the incident beam is reflected twice.

Embodiment II,

The present embodiment provides a gas detection probe. The gas detection probe in this embodiment is different from the gas detection probe in the first embodiment in that the first reflecting member 600 and the second reflecting member 700 are different.

Specifically, in this embodiment, referring to fig. 3 and 4, fig. 3 is a cross-sectional view of a gas detection probe according to the second embodiment of the present utility model, and fig. 4 is a schematic view of an optical path of the gas detection probe according to the second embodiment of the present utility model, the first reflecting member 600 includes a reflecting base 630 and a first high-reflectivity coating layer 640, the reflecting base 630 is disposed on the upper surface of the stem 100, the reflecting base 630 is a boss or a groove with a right trapezoid cross-section, the first high-reflectivity coating layer 640 is disposed on a slope of the boss or on a slope of the groove, and the second reflecting member 700 includes a second high-reflectivity coating layer 710 disposed on the inner surface of the optical window 500 on the cap 200. Compared with the first embodiment, the present embodiment can realize the functions of the first reflecting member 600 and the second reflecting member 700, thereby reducing the complexity of assembling the gas detection detector, reducing the number of separate optical elements, increasing the reliability of the product and reducing the cost on the premise of maintaining the performance. In other embodiments, the reflection seat 630 is a boss or a groove with a triangular cross section, and the first high-reflectivity coating 640 is disposed on an inclined surface of the boss or on an inclined surface of the groove.

In this embodiment, the second reflecting member 700 is disposed on the optical window 500, and half of the optical window 500 is provided with the anti-reflection film 510, and half is provided with the second high-reflectivity coating 710.

The preparation method of the detector for gas detection in this embodiment is as follows:

in step S100, the photodetector chip 300 is fixed on the upper surface of the socket 100 provided with the 2pin socket pin 800, and the distance from the axis is 1.72mm, which is located opposite to the first reflector 600 on the socket 100.

In step S200, the positive and negative electrodes of the photodetector chip 300 are electrically connected to the header pins 800.

In step S300, the stem 100 including the photodetector chip 300 and the first reflector 600 is coaxially aligned with the cap 200 including the second reflector 700, and the cap 200 is rotated until the second high-reflectivity coating 710 in the cap 200 is on the same side as the photodetector chip 300 on the stem 100, and then the stem is placed in a sealing machine in the measured atmosphere.

Step S400: and (5) placing the pre-aligned tube seat 100 and tube cap 200 into a sealing machine in the measured atmosphere environment for airtight sealing welding, and completing assembly and sealing.

In this embodiment, the external incident beam is perpendicular to the tube holder 100, and the beam passes through the transmission portion of the light transmission window 500, is reflected by the first high-reflectivity coating 640 and the second high-reflectivity coating 710, and finally is reflected to the photosensitive surface of the photodetector chip 300, and is transmitted to form a reflective reference detector light path. The light path is Z-shaped or N-shaped.

At this time, the relative angle between the incident beam and the first high-reflectivity coating 640 on the tube holder 100 is 107 °, the light passes through the first high-reflectivity coating 640 and the second high-reflectivity coating 710 in sequence according to the principle of total reflection, and finally the beam is incident on the photosensitive surface of the photodetector chip 300 at an angle of 34 ° with respect to the photodetector chip 300. The position distance of the photodetector chip 300 with respect to the central axis of the header 100 is the final offset distance after the incident beam is reflected twice.

The above description is only illustrative of the preferred embodiments of the present utility model and is not intended to limit the scope of the present utility model, and any alterations and modifications made by those skilled in the art based on the above disclosure shall fall within the scope of the appended claims.

Claims (10)

1. The utility model provides a gas detection is with detector, includes tube socket, tube cap and photoelectric detector chip, its characterized in that still includes reflector group, the tube cap is fixed on the tube socket and with the tube socket encloses into inclosed cavity, the light window has been seted up on the tube cap, the photoelectric detector chip with reflector group sets up in the cavity, the cavity intussuseption is filled with the gas under test, wherein, the light beam is followed the light window gets into behind the cavity throw on the reflector group, through reflector group reflection back throw on the photoelectric detector chip.

2. The gas detection probe of claim 1, wherein the set of reflectors comprises a first reflector and a second reflector, the light beam entering the chamber from the light window is projected onto the first reflector, reflected by the first reflector, projected onto the second reflector, reflected by the second reflector, and projected onto the photodetector chip.

3. The gas detection probe according to claim 2, wherein the photodetector chip and the first reflecting member are fixed to an upper surface of the stem, respectively, the cap is provided with the light window, and the second reflecting member is fixed to the light window inside the cap.

4. The gas detection probe according to claim 3, wherein the photodetector chip and the first reflecting member are disposed on both sides of the central axis of the stem, respectively.

5. The gas detecting probe according to claim 2, wherein an angle between the first reflecting member and an upper surface of the stem is not less than 1 °.

6. The gas detection probe according to claim 2, wherein the second reflecting member is disposed in parallel with a surface opposite to the upper surface of the stem.

7. The gas detecting probe according to claim 2, wherein the first reflecting member includes a first reflecting mirror and a base, the base is a boss having a right trapezoid or right triangle in cross section or a groove having a right trapezoid or right triangle in cross section, the first reflecting mirror is provided on an inclined surface of the boss or on an inclined surface of the groove, and the second reflecting member is a second reflecting mirror.

8. The gas detection probe according to claim 2, wherein the first reflecting member includes a reflecting base and a first high-reflectivity coating layer, the reflecting base is provided on an upper surface of the stem, the reflecting base is a boss having a right trapezoid or right triangle in cross section or a groove having a right trapezoid or right triangle in cross section, the first high-reflectivity coating layer is provided on an inclined surface of the boss or on an inclined surface of the groove, and the second reflecting member includes a second high-reflectivity coating layer provided on the optical window of the inner wall of the cap.

9. The gas detection probe of claim 8, wherein the stem and the reflector are integrally formed.

10. The gas detection probe of claim 1, further comprising a header pin electrically connected to the photodetector chip through the header.