CN106769737B - An optical fiber dust concentration measuring device - Google Patents

Abstract

The invention relates to the technical field of dust concentration measurement, and specifically discloses an optical fiber dust concentration measurement device, which sequentially includes a light source part, an input optical fiber, a measurement part, an output optical fiber, a signal conversion part and a data processing part. The measuring part includes a beam splitter, a first measuring area composed of a first transmitting end, a first attenuation area, a first receiving end, and a first connecting rod, and a first measuring area composed of a second transmitting end, a second attenuation area, a second receiving end, The second measurement area formed by the second connecting rod. The laser is divided into the first optical path and the second optical path by the beam splitter, and then enters the first measurement area and the second measurement area respectively for measurement. After the measurement, the output fiber is sent to the signal conversion part to convert the optical signal into an electrical signal, and the data processing part The laser attenuation coefficient is calculated from the received electrical signal. The invention utilizes the double optical path measurement and the differential operation method to eliminate the measurement error and improve the measurement accuracy.

Description

An optical fiber dust concentration measuring device

technical field

The invention relates to the field of dust concentration measurement, in particular to an optical fiber type dust concentration measurement device.

Background technique

The measurement methods of dust concentration mainly include optical analysis method and non-optical analysis method. The non-optical analysis method is difficult to monitor the dust concentration in real time due to the slow response speed of the detection equipment and the complicated processing. The dust concentration measurement technology based on optical analysis has the characteristics of high detection sensitivity, strong selectivity, and fast response speed.

The existing handheld dust concentration measuring device must require operators to measure on the spot, and in an environment with high dust concentration similar to coal mines, operators must take dust-proof measures when measuring, otherwise it will damage the respiratory tract and affect health. The existing chemical reaction type dust concentration sensor needs to collect and process the air dust, which has poor measurement time delay and cannot perform real-time measurement; the electrical dust concentration measurement device has poor safety. Electric sparks create a risk of mine explosion. For fiber-optic dust concentration sensors, the use of optical fibers for long-distance transmission of optical signals can realize remote measurement, but the measuring instrument is located in a high-dust area.

SUMMARY OF THE INVENTION

In view of the problems existing in the prior art, the present invention provides an optical fiber dust concentration measuring device, which transmits an optical signal to a measurement area through an optical fiber, transmits the optical signal through an optical fiber after measurement, and conducts two-way optical measurement to measure the error. Elimination not only realizes remote measurement, but also improves measurement accuracy.

An optical fiber dust concentration measuring device provided by the present invention comprises a light source part, a measurement part and a signal conversion part, the light source part and the measurement part are connected by an input optical fiber, and the measurement part and the signal conversion part are connected by an output optical fiber, wherein the measurement part includes a The beam splitter and the first measurement area and the second measurement area, the input end of the beam splitter is fixedly connected with the output end of the input fiber, the beam splitter divides the laser into a first optical path and a second optical path, and the first optical path enters the first measurement area, The second optical path enters the second measurement area; the measurement part is located at the measurement site, and the measurement part is far away from the light source part and the signal conversion part.

Further, the light source part includes a laser and a coupler, wherein the laser emits laser light and is coupled through the coupler and then transmitted to the input fiber.

Further, the first measurement area includes a first transmitting end, a first attenuation area, a first receiving end, and a first connecting rod, and the second measuring area includes a second transmitting end, a second attenuation area, a second receiving end, a second A connecting rod, wherein the first transmitting end and the first receiving end are fixedly connected by a first connecting rod; the second transmitting end and the second receiving end are fixedly connected by a second connecting rod; the first attenuation area is located between the first transmitting end and the first connecting rod Between the receiving ends, the second attenuation area is located between the second transmitting end and the second receiving end, and both the first attenuation area and the second attenuation area are dust-containing gas to be tested; the light of the first optical path in the first attenuation area The optical path is smaller than the optical path of the second optical path in the second attenuation region.

Further, the first transmitting end includes a first collimator and a first output mirror, the second transmitting end includes a second collimator and a second output mirror, wherein the distance between the first collimator and the first output mirror The distance between the second collimator and the second output mirror is the same; the first optical path passes through the first collimator and then passes through the first output mirror to illuminate the first attenuation area, and the second optical path passes through the second collimator and then passes through The second output mirror illuminates the second attenuation area, and the first optical path located in the first attenuation area is parallel to the second optical path located in the second attenuation area.

Further, the first transmitting end further includes a first single-lens shaper, and the second transmitting end further includes a second single-lens shaper, wherein the first single-lens shaper is installed between the first collimator and the first output mirror , after the first optical path passes through the first collimator, the spatial distribution of the laser energy is uniformized by the first single-lens shaper, and then irradiated to the first attenuation area by the first output mirror; the second single-lens shaper is installed in the second Between the collimator and the second output mirror, after the second optical path passes through the second collimator, the laser energy spatial distribution is uniformized by the second single lens shaper, and then irradiated by the second output mirror to the second attenuation area.

Further, the first receiving end includes a first input mirror and a third collimator, and the second receiving end includes a second input mirror and a fourth collimator, which are irradiated into the first input mirror through the first optical path of the first attenuation region. Then, it is irradiated into the third collimator, and then irradiated into the second input mirror through the second optical path of the second attenuation region, and then irradiated into the fourth collimator.

Further, the placement directions of the first collimator and the second collimator are the same, the placement directions of the third collimator and the fourth collimator are the same, and the placement directions of the first collimator and the third collimator are opposite, The placement direction of the second collimator is opposite to that of the fourth collimator.

Further, the output fiber includes a first output fiber and a second output fiber, wherein the input end of the first output fiber is connected to the output end of the first measurement area, the input end of the second output fiber is connected to the output end of the second measurement area, and the first output fiber is connected to the output end of the second measurement area. The output ends of the first output fiber and the second output fiber are both connected to the signal conversion part.

Further, the signal conversion part includes a first detector and a second detector, wherein the first detector is connected with the output end of the first output fiber, and the second detector is connected with the output end of the second output fiber; the first detector The optical signal of the first optical path is converted into an electrical signal, and the second detector converts the optical signal of the second optical path into an electrical signal.

Further, it also includes a data processing part, the data processing part is connected with the signal conversion part, and the signal conversion part sends the electrical signal to the data processing part for processing.

An optical fiber type dust concentration measuring device of the present invention has the following beneficial effects:

1. The measurement part is a pure optical structure, which is very safe to place on the measurement site;

2. Use optical fiber to transmit optical signals over long distances to realize remote measurement of dust concentration;

3. Double optical path measurement method, using differential operation to eliminate measurement errors and improve measurement accuracy;

4. Set the collimator to expand and contract the laser beam, so that the attenuation effect of the wide-beam laser in the attenuation area is more obvious, and the laser beam after the beam contraction is convenient for fiber transmission;

5. Set up a single lens shaper to homogenize the spatial distribution of laser energy, so that the measurement of dust concentration is carried out in a uniformly distributed light field, which can improve the adverse effect of the non-uniform distribution of dust concentration in the measurement space on the measurement results;

6. Use the influence of the dust concentration in the measurement area on the light intensity loss of the expanded beam to measure, the measurement process is carried out at the speed of light, there is no time delay problem, and the real-time measurement effect can be achieved.

Description of drawings

In order to illustrate the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the drawings that are required in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only These are some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative effort.

Fig. 1 is the composition diagram (1) of the optical fiber dust concentration measuring device of the present invention;

Fig. 2 is the composition diagram (1) of the measuring part of the optical fiber type dust concentration measuring device of the present invention;

Fig. 3 is the composition diagram of the light source part and the measuring part of the optical fiber type dust concentration measuring device of the present invention;

Fig. 4 is the composition diagram (2) of the optical fiber dust concentration measuring device of the present invention;

Fig. 5 is the composition diagram (2) of the measuring part of the optical fiber type dust concentration measuring device of the present invention;

Fig. 6 is the structure diagram (1) of the optical fiber type dust concentration measuring device of the present invention;

Fig. 7 is the structure diagram (2) of the optical fiber type dust concentration measuring device of the present invention;

In the figure: 1-light source part, 2-input fiber, 3-measurement part, 4-output fiber, 5-signal conversion part, 6-beam splitter, 7-first measurement area, 8-second measurement area, 9 -first optical path, 10-second optical path, 11-laser, 12-coupler, 13-first output fiber, 14-second output fiber, 15-first transmitting end, 16-first receiving end, 17- First connecting rod, 18-second transmitting end, 19-second receiving end, 20-second connecting rod, 21-first collimator, 22-first output mirror, 23-second collimator, 24 - second output mirror, 25 - third collimator, 26 - first input mirror, 27 - fourth collimator, 28 - second input mirror, 29 - first detector, 30 - second detector, 31-first single-lens shaper, 32-second single-lens shaper.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

As shown in FIG. 1 , the optical fiber dust concentration measuring device according to the first embodiment of the present invention includes a light source part 1, an input optical fiber 2, a measurement part 3, an output optical fiber 4 and a signal conversion part 5, a light source part 1 and a measurement part 3 The input optical fiber 2 is connected, and the measurement part 3 and the signal conversion part 5 are connected through the output optical fiber 4. The connection mode is not specifically limited in this embodiment. Preferably, flange connection is used. Similarly, the connection between the components in the present invention The methods are not specifically limited.

Specifically, as shown in FIG. 2, the measurement part 3 includes a beam splitter 6, a first measurement area 7 and a second measurement area 8, and the input end of the beam splitter 6 is fixedly connected to the output end of the input fiber 2; A beam of light is divided into two or more beams. There are currently two types: 1×N and 2×N. In this embodiment, a 1×2 beam splitter 6 is used, and the beam splitter 6 divides the laser light into the first optical path 9 and the The second optical path 10, the first optical path 9 enter the first measurement area 7, and the second optical path 10 enters the second measurement area 8. In order to reduce the measurement error, a beam splitter 6 with better spectral uniformity is selected to make the first optical path 9 The light intensity of the second optical path 10 is more equal; the measurement part 3 is located at the measurement site, and the measurement part 3 is far away from the light source part 1 and the signal conversion part 5, because the measurement part 3 is connected with the light source part 1 and the signal conversion part 5 through a long-distance optical fiber , the operator can operate the light source part 1 and the signal conversion part 5 at a position far away from the site, so as to realize the remote measurement of the dust concentration.

Specifically, as shown in FIG. 3 , the light source part 1 includes a laser 11 and a coupler 12. The laser 11 emits laser light and then enters the coupler 12. Since the laser light emitted by the laser 11 is approximately parallel light, the coupler 12 couples and focuses the laser light and transmits it. To the input fiber 2 , the input fiber 2 transmits the coupled laser light to a beam splitter 6 located in the measuring section 3 , and the beam splitter 6 splits the laser light to generate a first optical path 9 and a second optical path 10 .

Specifically, as shown in FIG. 4 , the output fiber 4 includes a first output fiber 13 and a second output fiber 14 , the input end of the first output fiber 13 is connected to the output end of the first measurement area 7 , and the input end of the second output fiber 14 The output end of the second measurement area 8 is connected, and the output ends of the first output fiber 13 and the second output fiber 14 are connected to the signal conversion part 5, and the signal conversion part 5 converts the light output by the first output fiber 13 and the second output fiber 14. The signal is converted into an electrical signal.

Specifically, as shown in FIG. 5 , the first measurement area 7 includes a first transmitting end 15 , a first attenuation area, a first receiving end 16 , and a first connecting rod 17 , and the second measuring area 8 includes a second transmitting end 18 , a first receiving end 16 , and a first connecting rod 17 . Two attenuation areas, a second receiving end 19, and a second connecting rod 20; the first transmitting end 15 and the first receiving end 16 are fixedly connected by the first connecting rod 17, and the second transmitting end 18 and the second receiving end 19 are connected by the second connecting rod 17. The connecting rod 20 is fixedly connected; the first attenuation area is located between the first transmitting end 15 and the first receiving end 16 , and the second attenuation area is located between the second transmitting end 18 and the second receiving end 19 . Both the first attenuation zone and the second attenuation zone are dust-containing gas to be tested. The optical path of the first optical path 9 in the first attenuation region is smaller than the optical path of the second optical path 10 in the second attenuation region. After the first optical path 9 is emitted from the first transmitting end 15, it is irradiated into the first attenuation area, and the laser light of the first optical path 9 is irradiated into the first receiving end 16 after being attenuated by the gas to be measured; the second optical path 10 is irradiated by the second transmitting end After 18 is emitted, it is irradiated into the second attenuation area, and the laser light of the second optical path 10 is irradiated into the second receiving end 19 after being attenuated by the gas to be tested; because the purpose of this case is to measure the dust concentration of the gas to be tested, the first emission The end 15 and the first receiving end 16 are both set as optical transmission devices with strong sealing performance. In order to further improve the measurement accuracy, the structures of the first transmitting end 15 and the second transmitting end 18 16 and the structure of the second receiving end 19 are set to the same structure. Since the optical path of the first optical path 9 in the first attenuation area is smaller than the optical path of the second optical path 10 in the second attenuation area, the attenuation of the first optical path 9 is smaller than that of the second optical path 9. The attenuation of the optical path 10.

Specifically, as shown in FIG. 6 , the first transmitting end 15 includes a first collimator 21 and a first output mirror 22 , the second transmitting end 18 includes a second collimator 23 and a second output mirror 24 , and the first collimator The collimator 21 and the second collimator 23 are placed in the same direction, and are used to expand the laser beams input into the first measurement area 7 and the second measurement area 8 into two wide beams of light, and the first optical path 9 becomes the first beam of light. The wide beam of light is irradiated into the first attenuation area through the first output mirror 22, and the second optical path 10 becomes the second wide beam of light and irradiated into the second attenuation area through the second output mirror 24. The first wide beam located in the first attenuation area The light is parallel to the second broad beam of light located in the second attenuation region. The first receiving end 16 includes a first input mirror 26 and a third collimator 25, the second receiving end 19 includes a second input mirror 28 and a fourth collimator 27, and the third collimator 25 and the fourth collimator 27 is placed in the same direction, but is opposite to the placement direction of the first collimator 21 and the second collimator 23. The first wide beam of light passing through the first attenuation zone is irradiated into the first input mirror 26 and then irradiated into the third collimator. The collimator 25 performs beam reduction focusing, and the second optical path 10 in the second attenuation region is irradiated into the second input mirror 28 and then irradiated into the fourth collimator 27 for beam reduction focusing. The distance between the first input mirror 26 and the third collimator 25 is the same as the distance between the second input mirror 28 and the fourth collimator 27 . The output end of the third collimator 25 is connected to the input end of the first output fiber 13 , and the output end of the fourth collimator 27 is connected to the input end of the second output fiber 14 . Preferably, the geometric centers of the first collimator 21 and the first output mirror 22 , the third collimator 25 , and the first input mirror 26 are on the same straight line, and are in the first measurement area 7 with the first optical path 9 The propagation paths of the second collimator 23 and the second output mirror 24, the fourth collimator 27, and the geometric centers of the second input mirror 28 are on the same line, and the second optical path 10 is in the second measurement area. The propagation paths in 9 and the second optical path 10 have the same propagation environment in the transmission element to improve the accuracy of dust concentration measurement.

The measurement part 3 is a pure optical device, which is installed in a mine or in a measurement environment prone to accidents with high safety performance. The signal conversion part 5 includes a first detector 29 and a second detector 30 , the first detector 29 is fixedly connected to the output end of the first output fiber 13 , and the second detector 30 is fixedly connected to the output end of the second output fiber 14 ; The first detector 29 converts the optical signal of the first optical path 9 into an electrical signal, and the second detector 30 converts the optical signal of the second optical path 10 into an electrical signal.

Specifically, an optical fiber dust concentration measuring device in this embodiment further includes a data processing part, the data processing part is connected with the signal conversion part 5, and the signal conversion part 5 sends the electrical signal to the data processing part for processing. The data processing part performs calculation through the electrical signal transmitted by the signal conversion part 5, and finally obtains the laser attenuation coefficient.

Specifically, as shown in FIG. 7 , in the second embodiment of the present invention, the optical fiber dust concentration measuring device, on the basis of the first embodiment, the first transmitting end 15 further includes a first single lens shaper 31 , a second The transmit end 18 also includes a second single lens shaper 32 . Since the laser light transmitted to the measuring part 3 through the input fiber 2 is coupled and focused by the coupler 12 and then transmitted, although the first optical path 9 and the second optical path 10 are connected by the first collimator 21 and the second collimator 23 The beam is expanded to become the first wide beam light and the second wide beam light, but the first wide beam light and the second wide beam light are Gaussian light, and the energy distribution of the light cross section is not uniform. If the laser is directly irradiated to the first attenuation area If the attenuation is large, the error will be large in the later data analysis, so the first single-lens shaper 31 is installed between the first collimator 21 and the first output mirror 22, and the second single-lens shaper 32 is installed between the first Between the second collimator 23 and the second output mirror 24, the first wide beam of light is uniformized by the first single lens shaper 31, and then irradiated to the first attenuation area for laser attenuation. Similarly, the second After the broad beam of light is uniformized by the second single lens shaper 32, the laser energy is irradiated into the second attenuation area for laser attenuation. The first single-lens shaper 31 and the second single-lens shaper 32 use the same aspherical lens, the design of the lens surface is determined according to the use environment, the present invention does not make specific limitations, and only needs to achieve the transformation of Gaussian light into flat top light purpose can be. To avoid unnecessary errors, the distance between the first collimator 21 and the first single-lens shaper 31 is set equal to the distance between the second collimator 23 and the second single-lens shaper 32 . In this embodiment, the first single-lens shaper 31 and the second single-lens shaper 32 are set to uniformize the spatial distribution of laser energy, so that the first broad beam light and the second broad beam light are in the first attenuation area and the second attenuation area The attenuation is more uniform, which in turn makes the results of post-processing data more accurate.

In this embodiment, the gas to be measured is measured by two paths of light respectively, and the laser attenuation coefficient is calculated according to the measurement data. Since the attenuation coefficient has a certain proportional relationship with the dust concentration of the gas to be measured, the measurement to be measured can be calculated according to a certain proportional relationship. Dust concentration of the gas. The specific algorithm of the measurement process and the laser attenuation coefficient of the fiber-optic dust concentration measuring device of the present embodiment is as follows:

由于第一光路9与第二光路10通过分束器6平均分为两束光，且第一准直器21与第二准直器23完全相同，所以I＝I′,故计算得α＝ln(I₂/I₁)/(l₁-l₂)。在距离l₁与l₂为固定值时，通过测量进入第三准直器25与第四准直器27的光强I₁与I₂，便可计算得出待测气体对激光的衰减系数α。由于一定的粉尘浓度对应着一定的激光衰减系数，而在实际应用中，可通过标准试验方法确定出粉尘浓度与激光衰减系数之间的对应关系，在测量中便可根据实验值算出粉尘浓度。The output light of the laser 11 is coupled by the coupler 12 and then enters the input fiber 2, and then is divided into two paths by the beam splitter 6 for transmission. The first optical path 9 enters the first collimator 21 for beam expansion and then exits from the first output mirror 22 , set the intensity of the laser light emitted from the first output mirror 22 as 1, the second optical path 10 enters the second collimator 23 for beam expansion and then emits from the second output mirror 24, and sets the laser light emitted from the second output mirror 24 The light intensity is I′, the light intensity of the first wide beam of light irradiated into the first input mirror 26 after being attenuated by the first attenuation zone is I ₁ , the second wide beam of light being attenuated by the second attenuation zone and then irradiated into the second input mirror The light intensity of 28 is I ₂ , the distance between the first collimator 21 and the third collimator 25 is l ₁ , the distance between the second collimator 23 and the fourth collimator 27 is l ₂ , and the attenuation coefficient is set is α, then

Since the first optical path 9 and the second optical path 10 are equally divided into two beams by the beam splitter 6, and the first collimator 21 and the second collimator 23 are exactly the same, I=I′, so α= ln(I ₂ /I ₁ )/(l ₁ -l ₂ ). When the distances l ₁ and l ₂ are fixed values, by measuring the light intensities I ₁ and I ₂ entering the third collimator 25 and the fourth collimator 27 , the attenuation coefficient of the gas to be measured to the laser light can be calculated. a. Since a certain dust concentration corresponds to a certain laser attenuation coefficient, in practical applications, the corresponding relationship between the dust concentration and the laser attenuation coefficient can be determined by standard test methods, and the dust concentration can be calculated according to the experimental value during measurement.

Preferably, a 1×3 beam splitter 6 can be selected. At this time, a third measurement area and a third detector need to be added, and the third measurement area, the first measurement area 7, and the light propagation device of the second measurement area 8 The structure is the same, the difference is that the optical path of the third optical path in the third attenuation area is different from the optical path of the first optical path in the first attenuation area and the optical path of the second optical path in the second attenuation area. The three optical paths pass through the third measurement area and then transmit to the third detector. The third detector converts the optical signal into an electrical signal and sends it to the data processing part. Effectively improve the measurement accuracy.

The entire fiber-optic dust concentration measurement device, based on the realization of remote measurement and the setting of a single lens shaper, uses a beam splitter to divide a laser beam into two beams equally, and inject the two beams into the same waiting station with different path lengths. The measurement is carried out in the measurement environment. After the two beams of light are attenuated, the two beams of light are output to the signal conversion part far away from the measurement area through the first output fiber and the second output fiber. The electrical signal is input to the data processing part for calculation, and finally the dust concentration of the gas to be measured is obtained. In this scheme, except that the optical paths of the first attenuation area and the second attenuation area are not equal, the other measurement environments are completely the same, so in the subsequent differential calculation, the optical path difference is used to calculate the laser attenuation coefficient, and all errors are eliminated by difference. , the calculated value is more accurate.

The present invention has been further described above with the help of specific embodiments, but it should be understood that the specific description herein should not be construed as a limitation on the spirit and scope of the present invention. Various modifications made in the embodiments all belong to the protection scope of the present invention.

Claims (8)

1. An optical fiber type dust concentration measuring device is characterized in that, comprising a light source part, a measurement part and a signal conversion part, the light source part and the measurement part are connected by an input optical fiber, and the measurement part and the signal conversion part are connected. Connected via output fiber, where: The measurement part includes a beam splitter, a first measurement area and a second measurement area, the input end of the beam splitter is fixedly connected to the output end of the input fiber, and the beam splitter divides the laser light into a first optical path and a second optical path. Two optical paths, the first optical path enters the first measurement area, and the second optical path enters the second measurement area; The measurement part is located at the measurement site, and the measurement part is far away from the light source part and the signal conversion part; The first measurement area includes a first transmitting end, a first attenuation area, a first receiving end, and a first connecting rod, and the second measuring area includes a second transmitting end, a second attenuation area, a second receiving end, and a first connecting rod. Two connecting rods, of which: The first transmitting end and the first receiving end are fixedly connected by the first connecting rod; the second transmitting end and the second receiving end are fixedly connected by the second connecting rod; The first attenuation area is located between the first transmitting end and the first receiving end, the second attenuation area is located between the second transmitting end and the second receiving end, and the first attenuation area is located between the second transmitting end and the second receiving end. Both the attenuation area and the second attenuation area are the gas to be tested containing dust; The optical path of the first optical path in the first attenuation region is smaller than the optical path of the second optical path in the second attenuation region; The first transmitting end includes a first collimator and a first output mirror, and the second transmitting end includes a second collimator and a second output mirror, wherein: The distance between the first collimator and the first output mirror is the same as the distance between the second collimator and the second output mirror; The first optical path is collimated by the first collimator and then irradiated to the first attenuation region through the first output mirror, and the second optical path is collimated by the second collimator and then passed through the first output mirror. The second output mirror illuminates the second attenuation area, and the first optical path located in the first attenuation area is parallel to the second optical path located in the second attenuation area. 2. A fiber-optic dust concentration measuring device according to claim 1, wherein the light source part comprises a laser and a coupler, wherein: The laser emits laser light and is coupled through the coupler and transmitted to the input fiber. 3. The optical fiber dust concentration measuring device according to claim 1, wherein the first transmitting end further comprises a first single-lens shaper, and the second transmitting end further comprises a second single-lens shaper , where: The first single-lens shaper is installed between the first collimator and the first output mirror, and the first optical path passes through the first collimator and is then shaped by the first single-lens After the laser energy is homogenized by the device, the first output mirror is irradiated to the first attenuation area; The second single-lens shaper is installed between the second collimator and the second output mirror, and the second optical path passes through the second collimator and is then shaped by the second single-lens The second output mirror irradiates the laser energy to the second attenuating region after the laser energy is uniformized by the device. 4 . The optical fiber dust concentration measuring device according to claim 3 , wherein the first receiving end comprises a first input mirror and a third collimator, and the second receiving end comprises a second input mirror and a fourth collimator, wherein: the first optical path passing through the first attenuation region is irradiated into the first input mirror and then into the third collimator, passing through the second attenuation region The second optical path is irradiated into the second input mirror and then into the fourth collimator. 5 . The fiber-optic dust concentration measuring device according to claim 4 , wherein the first collimator and the second collimator are placed in the same direction, and the third collimator and the The fourth collimator is placed in the same direction, the first collimator is placed in the opposite direction to the third collimator, and the second collimator is placed in the opposite direction to the fourth collimator . 6. An optical fiber dust concentration measuring device according to claim 5, wherein the output optical fiber comprises a first output optical fiber and a second output optical fiber, wherein: The input end of the first output fiber is connected to the output end of the first measurement area, the input end of the second output fiber is connected to the output end of the second measurement area, and the first output fiber is connected to the first output fiber. The output ends of the two output fibers are both connected to the signal conversion part. 7. The optical fiber dust concentration measuring device according to claim 6, wherein the signal conversion part comprises a first detector and a second detector, wherein: The first detector is connected to the output end of the first output fiber, and the second detector is connected to the output end of the second output fiber; The first detector converts the optical signal of the first optical path into an electrical signal, and the second detector converts the optical signal of the second optical path into an electrical signal. 8. An optical fiber dust concentration measuring device according to any one of claims 1 to 7, characterized in that, further comprising a data processing part, wherein: The data processing part is connected to the signal conversion part, and the signal conversion part sends the electrical signal to the data processing part for processing.

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