JPH0652235B2 - Method and apparatus for measuring color of powder in air flow - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a color measuring method and apparatus of a powder in an air stream such as ash in exhaust gas.

[Conventional technology]

The color measuring means includes a light projecting unit that projects light onto the sample, and a light receiving unit that receives the reflected light from the sample due to this light projecting. 2. Description of the Related Art A colorimeter for obtaining a hue, lightness or saturation value, or a color difference meter for measuring a difference from a standard color is generally known. Such color measuring means can be used for measuring the color of a fixed object such as a metal, a coating film, cloth, and paper.

However, if the conventional color measuring means is used as is,
For example, it is difficult to measure the color of ash in the exhaust gas at the time of coal combustion to measure the end-of-ash content in ash. On the other hand, it is conceivable to collect and fix a fixed amount of powder from the air flow and apply the above-mentioned color measuring means to it. However, not only is quantitative collection of powder and its fixation troublesome, but even if the amount of powder collected is determined in advance, the content of powder changes (in the case of ash in the above exhaust gas, coal combustion conditions and raw materials). The amount of ash contained in the exhaust gas changes depending on the type of charcoal).
In this case, the specified recovery amount is insufficient for measuring the color of the powder, and a measurement error may occur. Also, if a method is adopted in which a large amount of powder is collected and fixed in advance in anticipation of changes in the powder content, it will take a long time to complete the collection and color measurement, and the measurement result will be displayed on the powder source side. Can not be reflected in the control of.

In order to solve the above-mentioned problems, the inventors of the present invention have disclosed in JP-A-62-2
A method and a device as disclosed in Japanese Patent 17143 are proposed. That is, this method and apparatus measure the time-dependent change of the reflected light generated by the light projected onto the filter paper while adsorbing the powder in the air flow to the filter paper in the first cell, and the reflected light is in the steady state. After that, the color of the powder is judged from the characteristics of the reflected light obtained by projecting light on the filter paper in the second cell.

Further, conventionally, a device for detecting the visibility in the atmosphere having a very low concentration (detection of soot, clouds, raindrops, etc.) has been proposed (see, for example, JP-A-62-87830). Is possible because the target has a very low concentration, and cannot be applied to the application of measuring the color of powder.

[Problems to be Solved by the Invention]

The method and apparatus described in JP-A-62-217143 have the following disadvantages.

(1) Since the two cells of the first cell and the second cell are required, the device becomes large.

(2) Since the cell and the sensor unit such as the light emitter and the light receiver are provided in close proximity to each other, the sensor unit such as the light emitter and the light receiver is easily soiled. Further, the temperature of the sensor unit such as the light projector and the light receiver largely changes, and the accuracy is lowered.

(3) Since the ash on the sampled filter paper is moved and then measured, an error in reflected light intensity is likely to occur due to a change in the surface state of the ash. That is, the intensity of reflected light changes because the uniformly sampled ash shifts or cracks.

The present invention has been made to solve the above-mentioned points, and by separating the sample measuring unit and the sensor unit by using an optical fiber, while preventing the sensor unit from becoming dirty,
We aim to improve the accuracy by reducing the temperature change of the sensor part.
Another object of the present invention is to provide a method for measuring the color of powder in an air stream and the device thereof, which can increase the temperature of the sample measuring unit and further reduce the size of the entire device by using one cell. is there.

[Means for Solving the Problems]

In order to achieve the above object, the method for measuring the color of powder in an air stream according to the present invention, as shown in the drawing, supplies an air stream containing the powder from above a filter paper 7 placed substantially horizontally, While adsorbing the powder in the filter paper, the light source 16
From optical fiber 15 and transparent dustproof shutter 22
The transparent dustproof shutter 22 and the optical fiber 15 are used to measure the change with time of the reflected light caused by projecting the light through the
When the reflected light is in a steady state, the transparent dustproof shutter 22 is rotated to pass through the transparent dustproof shutter under the optical fiber 15 (a hole without anything penetrating to the side) 21. Is positioned, and the color of the powder is judged from the characteristics of the reflected light obtained by projecting light onto the filter paper through the through hole 21 of the transparent dustproof shutter.

In the method of the present invention, the fluctuation of the light source illuminance can be corrected by correcting the error of the reflected light intensity measurement value due to the output fluctuation of the light source 16 by the separately measured light source illuminance measurement value.

Further, the corrected reflected light intensity of the blank filter paper is measured in a state where the through hole 21 of the transparent dustproof shutter 22 is positioned below the optical fiber 15, and when the measured value becomes equal to or less than the limit value, By judging as dirty,
The dirt on the tip of the optical fiber can be detected.

In order to detect the dirt of the transparent dustproof shutter, the difference between the reflected light intensities before and after the powder-containing airflow is sucked in the shutter closed state in which the transparent portion of the transparent dustproof shutter 22 is positioned below the optical fiber 15 and the spring. The dirt on the transparent dustproof shutter surface is detected from the correlation with the difference in the reflected light intensity before and after the suction of the powder-containing air flow in the shutter open state in which the through hole 21 of the transparent dustproof shutter 22 is positioned below 15. To do

Further, in order to detect a trouble of filter paper feeding, an optical switch 45 is provided on the upper side of the filter paper, and the optical switch is turned off when the surface of the filter paper on which the powder adheres is viewed, and the optical switch is turned on when the surface of the blank paper is viewed. The fact that the filter paper feed is operating reliably is detected by the characteristics of the optical switch output pattern during filter paper feed.

In addition, starting suction from a blank filter paper, covering the filter paper with powder, and measuring the integrated value of the amount of suction gas during one batch measurement until the reflected light intensity becomes constant, and the powder adheres to the filter paper surface. The powder concentration in the air stream can be calculated with the amount being a fixed amount per unit area.

As shown in the drawing, the color measuring apparatus for powder in airflow of the present invention comprises an upper cell 2 and a lower cell 3 provided with a sealing means 4, and a vacuum pump 5 or an induction fan is connected to the lower portion of the upper cell 2. 1 closed cell for introducing powder-containing air stream from
And a filter paper supplying / moving means 8 for intermittently supplying / moving the filter paper 7 in a substantially horizontal direction between the upper cell and the lower cell, and projecting and reflecting light on the filter paper 7 which adsorbs powder in the air stream. And a sample measuring section 14 for obtaining
A light source 16, a reflected light sensor 17, and a light source sensor 18, which are connected via a sensor unit 20, and a through hole 21 provided between the sample measuring unit 14 and the sensor unit 20. Dustproof shutter 22
And a control device 24 connected to the reflected light sensor 17, the light source sensor 18, the filter paper supply / moving means 8, the sealing means 4 and the vacuum pump 5 or the induction fan, and a calculation / display device connected to this control device. And 25.

The sample measuring unit 14 has a shape that matches the light receiving angle of the optical fiber 15.

Further, as the transparent dustproof shutter 22, a heat resistant glass plate coated with an antireflection coating is used, and two through holes 21 are provided in the diameter direction in the heat resistant glass plate, and the shutter is opened and closed by rotating the heat resistant glass plate by 90 °. As described above, the support shaft 33 is inserted in the center of the shutter 22.

Further, as a sample line for powder-containing air flow, a sample gas introduction pipe 6 for introducing the powder-containing air flow connected to the upper part of the closed cell 1 is a vertical pipe, and this vertical pipe is It is desirable to be connected to a circulation line 47 provided in the main pipe 46 of the air flow.

In the method and apparatus of the present invention, it is desirable to use a bundle fiber as the optical fiber to integrate the light emitting and receiving fibers.

[Action]

When the powder-containing airflow is being sucked, the measurement is performed through the transparent portion of the transparent dustproof shutter 22 in order to prevent the sensor portion 20 from being soiled.

While the reflected light from the filter paper 7 is changing, it is in a state of being reflected by the filter paper itself, and it can be considered that the reflected light after the reflected light becomes a steady state is only due to the powder. Therefore, the hue, brightness, or saturation of only the powder can be measured by observing the characteristics of the reflected light due to the light projection after the steady state.

After the steady state, the transparent dustproof shutter 22 is rotated, the through hole 21 of the shutter 22 is positioned below the optical fiber 15, and light is projected to receive reflected light.

〔Example〕

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. However, unless otherwise specified, the materials, shapes, relative positions, etc. of the constituent devices described in this embodiment are not intended to limit the scope of the present invention thereto, but are merely an explanation. It's just an example.

The present embodiment is an application of the present invention to measuring the color of powder in exhaust gas in coal combustion, that is, the color of ash to measure the unburned content in ash. FIG. 1 shows the overall structure of the device, FIG. 2 shows a vertical cross section of the device, and FIG. 3 shows the periphery of the sample measuring section.

Reference numeral 1 denotes a closed cell, which comprises an upper cell 2 and a lower cell 3 having a sealing means 4 such as a sealing air cylinder. A vacuum pump 5 or an induction fan is connected to the lower portion of the lower cell 3 to connect the upper cell 2 A sample gas introduction pipe 6 is connected to the upper part of the.

Filter paper feeding / moving means 8 for intermittently feeding / moving the filter paper 7 in a substantially horizontal direction between the upper cell 2 and the lower cell 3 are provided on the left and right of the closed cell 1. The filter paper supply / moving means 8 includes a filter paper reel 10, a guide roller 11, and a drive roller 1.
2. It comprises a drive roller motor 13. Reference numeral 14 is a sample measuring section, which is a section for projecting light on filter paper which adsorbs ash in exhaust gas to obtain reflected light. This sample measuring unit 1
4, a sensor unit 20 including a light source 16, a reflected light sensor 17, and a light source sensor 18 via an optical fiber 15.
Are connected.

A rotatable transparent dustproof shutter 22 having a through hole 21, as shown in FIGS. 4 and 5, is provided between the sample measuring unit 14 and the sensor unit 20. Furthermore, sensor 17 for reflected light, sensor 18 for light source, filter paper supply /
A control device 24 is connected to the motor 13 of the moving means 8, the sealing means 4, and the control valve 23 at the inlet of the vacuum pump 5. The calculation / display device 25 is connected to the control device. In FIG. 2, 26 is a shutter drive motor, 27 is a temperature sensor, 28 is a heater, 29 is a pressure sensor, and 30 is a porous glass plate. The temperature sensor 27 and the pressure sensor 29 are also connected to the control device 24. Further, the case where the air cylinder 31 and the seal piston 32 are combined as the sealing means is shown. θ is the light receiving angle.

Further, in FIG. 3, 33 is a support shaft for inserting into the central hole 34 of the shutter 22, 35 is a collar, 36 is a bush, and 37 is an optical switch.

As shown in FIGS. 3 and 14, the sample measuring unit 14 has a shape that matches the light receiving angle θ of the optical fiber 15. That is, the NA (numerical aperture) of the optical fiber 15 is used to arrange the sample measuring unit 14, and the optical fiber alone constitutes a light condensing system. In this way, the sample measuring unit 14
In addition to downsizing, there is an advantage that the lens is not necessary, and therefore, the error due to the dirt of the lens is eliminated and the accuracy is improved.

Further, it is desirable to use a heat-resistant glass plate coated with an antireflection coating as the transparent dustproof shutter 22,
As shown in FIGS. 4 and 5, two through holes 21 are bored in the heat-resistant glass plate in the diameter direction, and the shutter is opened and closed by rotating the heat-resistant glass plate by 90 °. The support shaft 33 is inserted into the central central hole 34. The shutter 22 is rotated by a shutter drive motor 26, as shown in FIG. The shutter rotation position is detected by marking the marking portion 38 such as black matte coating provided on the peripheral surface of the disk-shaped shutter.
It is performed by detecting with the optical switch 37. Further, the shutter open / closed state is detected by measuring the reflected light intensity. That is, as shown in FIG. 15, when the shutter is closed, the intensity of the reflected light increases due to the reflection on the glass surface. Then, the open / closed state of the shutter is determined based on the reflected light levels before and after the shutter rotation.

In the color measuring device configured as described above, the exhaust gas containing unburned ash is supplied from above the filter paper 7 placed substantially horizontally so that the ash in the exhaust gas is adsorbed on the filter paper 7 and On the other hand, light is emitted from the light source 16 through the optical fiber 15 and the transparent portion of the transparent dustproof shutter 22. Then, the reflected light generated by this is transmitted to the transparent dustproof shutter 2
The sensor 17 for reflected light detects it via the transparent part 2 and the optical fiber 15, and measures the change with time of the reflected light. When the reflected light reaches a steady state, the transparent dustproof shutter 22 is rotated to position the through hole 21 of the shutter 22 below the optical fiber 15, and the filter paper 7 is projected through this through hole 21. The ash color is judged from the characteristics of the reflected light.

As shown in FIG. 6, the control device 24 includes a steady state determination means 40, a powder color determination means 41, a temperature control means 42, a data output means 43, an operating part control means 44, and a light source illuminance variation correction means 49. ing. Steady state determination means 40
Is the output from the reflected light sensor 17 and the pressure sensor 2
The closed cell 1 receives the output from 9 and changes from both outputs with time.
In the process in which the reflected light from the inner filter paper 7 is adsorbed by the ash on the filter paper 7, it is determined whether or not a steady state is reached. That is,
When the ash in the exhaust gas is adsorbed on the filter paper 7, the influence of reflection by the filter paper 7 itself becomes smaller according to the amount of the adhered ash. As a result, the intensity of the reflected light from the filter paper 7 decreases, and as a result, the output of the reflected light sensor 17 decreases as shown in FIG. Therefore, if the ash is continuously adsorbed, at the time T when the output of the reflected light sensor 17 becomes substantially constant, the entire surface of the filter paper 7 in the closed cell 1 is covered with ash, and the reflection of the filter paper itself is prevented. It can be judged that there was no effect and that only ash was reflected. However, the amount of ash in the exhaust gas decreased due to factors such as trouble on the combustion side or the sampling line, and the filter paper 7 was temporarily removed.
When the ash adheres to the sheet, the output of the reflected light sensor 17 becomes substantially constant, although the reflected light is affected by the filter paper itself. However, in this case, the pressure on the downstream side of the filter paper does not decrease any more because the ash has stopped adhering and shows a constant value. Therefore, when the pressure shows a constant value due to the output from the pressure sensor 29,
It is judged that ash deposition has stopped, and that it has not reached a steady state.

The steady state determination means 40 determines that the steady state is achieved when the output from the reflected light sensor 17 is constant and the output from the pressure sensor 29 is decreasing.

The powder color determination means 41 receives the output from the reflected light sensor 17, and from the output, captures the characteristic of the reflected light from the filter paper 7 after the above-mentioned steady state, that is, the reflected light due to the ash, (In the case of this embodiment, the lightness of ash) is determined, and the amount of unburned ash in the ash is calculated from the color of ash and sent to the data output means 43 and further to the calculation / display device 25.
That is, the reflected light sensor 17 outputs an output according to the intensity (brightness) of the reflected light, and the powder color determination means 41 determines the lightness of ash from this output, and the data output means 43 and the calculation / display device. In 25, the ratio of the unburned ash content is calculated from the correlation data between the ash brightness (corresponding directly to the output of the reflected light sensor 17) shown in FIG. 8 and the unburned ash content shown in FIG. indicate.

The actuation unit control means 44 operates upon receipt of the judgment of the steady state from the steady state judgment means 40, outputs a seal release signal to the sealing means 4 and a stop signal to the control valve 23 of the vacuum pump 5. A drive command is output to the drive roller motor 13, the reflected light becomes steady and the measured filter paper portion is sent to the outside of the closed cell 1, and a stop signal is sent to the motor 1.
3, the drive signal is output to the control valve 23, and the seal actuation signal is output to the sealing means 4.

The temperature control means 42 receives the output from the temperature sensor 27, operates the heater 28, and controls the filter paper 7 in the closed cell 1 and the atmosphere around it to about 100 ° C.

In order to correct the illuminance fluctuation of the light source 16, the error of the reflected light intensity resulting from the fluctuation of the light source illuminance due to the aging of the lamp and the fluctuation of the power supply voltage is corrected by the separately measured light source illuminance value. That is, when the reflected light output fluctuation of the blank filter paper when the light source illuminance is artificially fluctuated in advance and the correlation equation between them is obtained, a linear equation as shown in FIG. 9 is obtained. By using FIG. 9, the difference between the reflected light intensity of the blank filter paper obtained from the output of the light source sensor 18 at the time of measurement and the output of the reflected light sensor 17 at that time is set as the corrected sensor output.

Further, when detecting the tip (lower end) of the optical fiber 15, the reflected light intensity of the blank filter paper is measured every time the shutter 22 is open, and when the level is below the limit value, the tip of the optical fiber 15 is contaminated. judge. Then, purge air is flown to remove dirt on the tip of the optical fiber 15. As a result, it is possible to improve reliability, accuracy, and maintain performance.

Further, when detecting the dirt on the transparent dustproof shutter 22, the correlation between the difference in the reflected light intensity before and after the exhaust gas suction when the shutter 22 is closed and the difference in the reflected light intensity before and after the exhaust gas suction when the shutter 22 is open is correlated. , As shown in FIG. 10, it is obtained in advance, and the dirt on the surface of the shutter 22 is detected from this correlation. As a result, it is possible to improve accuracy and maintain performance.

In order to detect the reliable movement of the filter paper 7, as shown in FIG. 11, the optical switch 4 is placed above the filter paper on the exit side of the closed cell 1.
5 is provided, and when viewing the filter paper with ash attached, the optical switch 45
Is turned off, and the optical switch 45 is turned on when the blank filter paper surface is viewed. If the output shown in FIG. 12 is obtained, it is determined to be normal, and if the output of the optical switch appears to be in a straight line at the on position, it is determined to be abnormal. This makes it possible to detect a filter paper jam and a filter paper feeding trouble due to a filter paper shortage, thereby improving reliability.

In addition, the integrated value of the suctioned exhaust gas amount of 1 batch (the time from the suction of the blank filter paper until the filter paper is covered with ash and the reflected light intensity becomes constant) was measured, and the ash adhesion amount was 2 to 10 mg / cm
^The dust concentration is calculated from the curve shown in FIG. 13 using ² filter papers, for example, 3 mg / cm ² filter paper. That is, irrespective of the unburned content in the ash, the surface of the filter paper is covered with ash for about 3 m.
Since it is g / cm ² filter paper, the dust concentration is calculated back from this.

Also, when introducing sample gas, if there is a horizontal part in the sampling line, powder, such as ash, will accumulate when sample gas suction is stopped, and a large amount of powder will flow in at once when suction is restarted. Is a vertical short tube as much as possible,
The gas up to that point always flows in the circulation line to prevent the accumulation of ash in the sampling line. That is, as shown in FIG. 16, a sample gas introduction pipe 6 connected to the upper part of the closed cell 1 of a color measuring device, for example, an unburned ash in-medium meter is a vertical pipe, and this vertical pipe is It is connected to a circulation line 47 provided in a main pipe 46 (boiler flue) for a powder-containing air flow, for example, a boiler exhaust gas. 48 is a circulation fan.

In addition, although the said Example is related to the measurement of the color of the ash in exhaust gas, it is needless to say that this invention can be applied to the measurement of the color of the powder in another air stream.

Further, in determining the color of the powder, the type of the reflected light sensor may be changed to determine the hue or the saturation.

〔The invention's effect〕

Since the present invention is configured as described above, it has the following effects.

(1) Since the sample measuring unit and the sensor unit are separated by using an optical fiber, the temperature change of the sensor unit is reduced,
It is possible to improve accuracy and prevent contamination of the sensor unit. In addition, the sample measuring unit, without degrading the accuracy,
It is possible to raise the temperature.

(2) Since the number of closed cells is one, the entire device can be downsized. Further, in the conventional 2-cell system, the problem of the change of the filter paper state due to the movement of the filter paper is eliminated.

(3) Since the transparent dustproof shutter having the through hole is provided at the lower end of the optical fiber, it is possible to prevent the optical fiber and the sensor unit from being soiled.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of a color measuring apparatus for powder in an air stream according to the present invention, FIG. 2 is an explanatory view of a longitudinal section of the same, and FIG. 3 is an enlarged sectional explanatory view showing the periphery of a sample measuring section. Fig. 4 is a plan view of a transparent dustproof shutter, Fig. 5 is a sectional view of the same, Fig. 6 is a detailed view around the control device, Fig. 7 is an output characteristic diagram of a reflected light sensor, and Fig. 8 is for reflected light. A graph showing the relationship between the sensor output and the amount of unburned ash, Fig. 9 is a graph showing the relationship between the sensor output for the light source and the sensor output for the reflected light in the state of the blank filter paper, and Fig. 10 is the graph when the shutter is open. A graph showing the relationship between the reflected light intensity and the reflected light intensity when the shutter is closed, FIG. 11 is an explanatory view of an apparatus for detecting movement of filter paper, and 12th is 11th.
Output characteristic diagram of the optical switch in the figure, FIG. 13 is a graph showing the relationship between the amount of dust adhesion and the sensor output for reflected light,
14 is an explanatory view showing one example of the structure of the sample measuring section, FIG. 15 is a characteristic diagram of reflected light intensity by opening and closing the shutter, and FIG. 16 is an explanatory diagram around the sampling line. 1 ... closed cell, 2 ... upper cell, 3 ... lower cell, 4
... Sealing means, 5 ... Vacuum pump, 6 ... Sample gas introduction tube, 7 ... Filter paper, 8 ... Filter paper supply / moving means, 10 ...
... filter paper reel, 11 ... guide roller, 12 ... drive roller, 13 ... drive roller motor, 14 ... sample measuring unit, 15 ... optical fiber, 16 ... light source, 17 ... reflected light sensor, 18 ...... Light source sensor, 20 ...... Sensor part, 21 ...... Through hole, 22 ...... Transparent dustproof shutter, 23 ...... Control valve, 24 ...... Control device, 25 ...... Calculation / display device, 26 ...... Shutter Drive motor, 27 ...
... Temperature sensor, 28 ... Heater, 29 ... Pressure sensor, 30 ... Porous glass plate, 31 ... Air cylinder, 32 ... Seal piston, 33 ... Spindle, 34 ...
Central hole, 35 ... Collar, 36 ... Bush, 37 ...
Optical switch, 38 ... Marking part, 40 ... Steady state judging means, 41 ... Powder color judging means, 42 ... Temperature control means, 43 ... Data output means, 44 ... Actuating part control means, 45 ... ... optical switch, 46 ... main pipe, 47 ... circulation line, 48 ... circulation fan, 49 ... light source illuminance fluctuation correction means

Continuation of the front page (56) Reference JP 62-217143 (JP, A) JP 62-87830 (JP, A) JP 58-113736 (JP, A) JP 57-184953 (JP , A)

Claims (10)

[Claims] 1. An air flow containing powder is supplied from above a filter paper (7) placed substantially horizontally to adsorb the powder in the air flow to the filter paper, and a light source (16) from this fiber to the filter paper. (15) and transparent dustproof shutter (22)
The time-dependent change of reflected light caused by the light is measured via the transparent dustproof shutter (22) and the optical fiber (15), and when the reflected light is in a steady state, the transparent dustproof shutter. (22) was rotated to locate the through hole (21) of the transparent dustproof shutter below the optical fiber (15), and the light was projected onto the filter paper through the through hole (21) of the transparent dustproof shutter. A method for measuring the color of powder in an air stream, which comprises determining the color of powder from the characteristics of reflected light. 2. The color measuring method for powder in an air flow according to claim 1, wherein an error in the reflected light intensity measurement value due to the output fluctuation of the light source (16) is corrected by the separately measured light source illuminance measurement value. 3. The reflected light intensity of a blank filter paper is measured with the through hole (21) of the transparent dustproof shutter (22) positioned below the optical fiber (15), and the measured value is below a limit value. 2. The method for measuring the color of powder in an air flow according to claim 1, wherein it is determined that the tip of the optical fiber is dirty. 4. The difference between the reflected light intensities before and after the powder-containing air flow is sucked in the shutter closed state in which the transparent portion of the transparent dustproof shutter (22) is positioned below the optical fiber (15),
From the correlation with the difference in reflected light intensity before and after suction of the powder-containing air flow in the shutter open state in which the through hole (21) of the transparent dustproof shutter (22) is located below the optical fiber (15), the transparent dustproof dustproof The color measuring method for powder in an air flow according to claim 1, wherein dirt on the shutter surface is detected. 5. An optical switch (45) is provided on the upper side of the filter paper,
The optical switch is turned off when looking at the filter paper on which the powder adheres, the optical switch is turned on when looking at the blank filter paper, and the filter paper feed is operating reliably due to the characteristics of the optical switch output pattern during filter paper feed. The method for measuring the color of powder in an air stream according to claim 1, wherein 6. An integrated value of the suction gas amount during one batch measurement time from the start of suction from a blank filter paper until the filter paper is covered with powder and the intensity of the reflected light becomes constant, and the amount of suction gas on the filter paper surface is measured. 2. The method for measuring the color of powder in an air stream according to claim 1, wherein the powder concentration in the air stream is calculated with the powder adhesion amount being a fixed amount per unit area. 7. An upper cell (2) and a lower cell (3) provided with a sealing means (4), and a vacuum pump (5) in the lower part.
Alternatively, one closed cell (1) that connects an induction fan and introduces a powder-containing air stream from above and a filter paper (7) is intermittently supplied and moved in a substantially horizontal direction between the upper cell and the lower cell. A sample measuring unit (1) that obtains reflected light by projecting light onto filter paper supply / moving means (8) and filter paper (7) that adsorbs powder in the air stream.
4), a light source (16) connected to the sample measuring section via an optical fiber (15), and a reflected light sensor (17)
And a sensor section (2) including a light source sensor (18)
0), a rotatable transparent dustproof shutter (22) having a through hole (21) provided between the sample measuring section (14) and the sensor section (20), and a reflected light sensor (1).
7), a light source sensor (18), a filter paper supply / moving means (8), a sealing means (4) and a control device (24) connected to the vacuum pump (5) or an induction fan, and this control device. A color measuring device for powder in an air stream, which further comprises a calculation / display device (25). 8. The method for measuring the color of powder in an air stream according to claim 7, wherein the shape of the sample measuring section (14) is matched with the light receiving angle of the optical fiber (15). 9. A transparent dustproof shutter (22) is made of a heat-resistant glass plate having an antireflection coating, and the heat-resistant glass plate is provided with two through-holes (21) in the diameter direction, and the opening and closing of the shutter is heat-resistant. The color measuring method for powder in an air flow according to claim 7, wherein a support shaft (33) is inserted in the center of the shutter (22) so as to be performed by rotating the glass plate by 90 °. 10. A sample gas introduction pipe (6) connected to the upper part of the closed cell (1) for introducing a powder-containing air flow is a vertical pipe, and this vertical pipe is used as a powder-containing air flow book. The color measuring device for powder in air flow according to claim 7, which is connected to a circulation line (47) provided in a pipe (46).