JP6952346B2 - Light scattering dust densitometer for cloudy exhaust gas - Google Patents

Description

The present invention relates to a light scattering type dust densitometer, and in particular, dust in a cloudy exhaust gas that is cloudy due to adsorption and coexistence of mist (droplet particles) and dust (solid particles) in the flue below the dew point. The present invention relates to a light scattering dust densitometer for cloudy exhaust gas, which can continuously and accurately measure the concentration in the flue for a long period of time.

Exhaust gas generated in various factories contains harmful substances such as sulfur oxides and nitrogen oxides. For this reason, it is obligatory to install an exhaust gas treatment device such as a desulfurization device or a denitration device in a path (exhaust gas path) for discharging exhaust gas into the atmosphere through a chimney.

On the other hand, there are also predetermined emission concentration regulations for dust. For example, in a paper mill or the like, the mist used in the exhaust gas treatment device is contained in the exhaust gas and becomes white smoke, which is discharged from the chimney. Then, there are cases where local residents see the white smoke emitted from the chimney and feel that dust exceeding the regulation value is being emitted, and inquire at the factory or the like.

Therefore, in various factories, a method of clearly indicating that white smoke is simply due to mist and does not contain dust exceeding the regulation standard, that is, a method of constantly confirming that the regulations related to dust emission are observed. (Means) was strongly desired.

As a means for measuring the dust concentration, a light scattering type dust densitometer has been conventionally known. However, the conventional light scattering type dust concentration meter can continuously measure the dust concentration in the exhaust gas in real time, but for the exhaust gas containing mist (white turbid exhaust gas below the dew point) after being treated by a desulfurization device or the like. In principle, it is difficult to accurately measure the dust concentration due to the influence of a large amount of mist. That is, conventionally, the light scattering type dust concentration meter has a problem that it cannot be applied to the measurement of the dust concentration of the exhaust gas containing mist.

On the other hand, the inventor of the present application is for collecting a part of the cloudy exhaust gas in the flue directly in the flue continuously and accurately, and continuously for a long period of time, in other words, in a laboratory outside the flue. We have invented a light-scattering dust densitometer that can measure the duct concentration in cloudy exhaust gas continuously, accurately, and continuously for a long period of time without using a sampling tube. The patent application shown in 3 has been filed and the patent right has already been obtained.

The light scattering type dust densitometer described in Patent Document 1 is a dust densitometer that measures the dust concentration in a cloudy exhaust gas in which mist and dust are adsorbed and coexist in the flue, and is in the cloudy exhaust gas in the flue. It is equipped with a vaporizer that vaporizes the mist, a light irradiator that irradiates the area where the mist is vaporized in the flue, and a scattered light detector that detects the scattered light reflected by the dust from which the mist has been removed. , It is configured to obtain the dust concentration in the cloudy exhaust gas based on the scattered light intensity detected by the scattered light detector.

The light scattering type dust densitometer described in Patent Document 2 is a dust densitometer that directly measures the dust concentration in the cloudy exhaust gas in the flue, and is a measurement target after separating the white turbid exhaust gas to be measured in the flue. An air blow mechanism that forms an air curtain downstream of the vaporizer that separates the vaporizer that vaporizes the mist in the cloudy exhaust gas, the area where the mist remains vaporized through the vaporizer, and the cloudy exhaust gas that does not pass through the vaporizer. Etc., and it is configured to detect the scattered light reflected by the mist-removed dust in the air curtain to obtain the dust concentration in the cloudy exhaust gas.

The light scattering type dust densitometer described in Patent Document 3 takes in the cloudy exhaust gas to be measured in the flue, vaporizes the mist with a vaporizer, and reflects it on the dust from which the mist has been removed in the region where the mist is vaporized. In a dust densitometer that detects scattered light and directly measures the dust concentration in the cloudy exhaust gas in the flue, an intermittent air blow mechanism that intermittently generates air near the intake port of the cloudy exhaust gas to be measured by the vaporizer ( It is configured to have a dirt prevention function on the entrance side of the vaporizer).

Japanese Patent No. 5453607 Japanese Patent No. 5976885 Japanese Patent No. 624941

Here, in Patent Document 3, an intermittent air blow mechanism is provided, and air is intermittently generated near the intake port of the cloudy exhaust gas to be measured by the vaporizer, so that the mist vaporized is generated by the light scattering type dust densitometer. It does not condense near the entrance and accumulate as drain, and as a result, it is possible to prevent dust from adhering to the vicinity of the entrance and further growing. This makes it possible to continuously, accurately, and continuously measure the dust concentration in the exhaust gas containing a large amount of mist for a long period of time.

On the other hand, in the light scattering type dust densitometer of Patent Document 3 (Patent Document 1 and Patent Document 2), the cloudy exhaust gas is taken in from the inlet, the mist is vaporized by the vaporizer, and the exhaust immediately after exiting from the outlet of the vaporizer. The gas (exhaust gas vaporized by mist) is irradiated with light by a light irradiator, and the scattered light detector is configured to detect the scattered light reflected by the dust.

For this reason, when the measurement is continuously performed for a longer period of time, it is provided near the outlet of the vaporizer, and the light is emitted (exported) from the photodetector toward the exhaust gas and reflected by the dust. It is conceivable that mist, dust, etc. gradually accumulate on the translucent surface at which the scattered light is incident toward the scattered light detector, and there is room for improvement in this respect.

In view of the above circumstances, the present invention is provided near the outlet of the vaporizer, irradiates light from the light irradiator toward the exhaust gas, and causes the scattered light reflected by the dust to enter toward the scattered light detector. It is an object of the present invention to provide a light scattering type dust concentration measuring device capable of preventing (suppressing) the accumulation of mist, dust, etc. on the surface.

The present inventor irradiates light from a photodetector toward exhaust gas, and prevents mist, dust, etc. from accumulating on a translucent surface that causes scattered light reflected by dust to enter toward a scattered light detector. We have found a means and have completed the present invention.

(1) The present invention is a dust densitometer for cloudy exhaust gas for directly detecting dust in cloudy exhaust gas in which mist and dust are adsorbed and coexisting in the flue and measuring the dust concentration. A vaporizer that is disposed in the flue and takes in the cloudy exhaust gas to be measured and vaporizes the mist, a light irradiator that irradiates a region where the mist is vaporized, and the light. The mist emits light emitted from the light irradiator from the dust detection device including the scattered light detector that detects the scattered light reflected by the dust and the outlet side of the exhaust gas that vaporizes the mist of the vaporizer. A translucent surface that ejects air toward the translucent surface that projects light into the vaporized region and toward the translucent surface that receives the scattered light reflected by the dust by the scattered light detector. It is characterized by being provided with an air blow mechanism for use.

(2) In the above (1), the present invention provides the air curtain that separates the region where the mist is vaporized through the vaporizer from the cloudy exhaust gas that does not pass through the vaporizer. An air blow mechanism for an air curtain formed from the outlet side of the exhaust gas to the downstream in the flow direction of the exhaust gas is provided, and the air blow mechanism for the translucent surface is in a state where the mist is vaporized through the vaporizer in the air curtain. An air discharge port for ejecting air is provided in the region where the above is maintained, and a region where the mist is maintained in a vaporized state through the vaporizer in the air curtain on the downstream side in the flow direction of the exhaust gas from the air discharge port. It may be configured to eject the air toward the side of the translucent surface provided inside.

(3) In the above (1) or (2), the present invention is a front view from the downstream side in the flow direction of the exhaust gas, and the air discharge port is in the vertical direction of the exhaust gas outlet and the translucent surface. It may be provided between.

According to the present invention, by providing an air blow mechanism for a translucent surface, light is emitted from a photoirradiator toward an exhaust gas, and scattered light reflected by dust is incident on a scattered light detector. It is possible to prevent (suppress) the accumulation of mist and dust on the surface.

Therefore, according to the light scattering type dust densitometer of the present invention, the dust concentration in the cloudy exhaust gas, which is cloudy due to the adsorption and coexistence of mist and dust when the inside of the flue is below the dew point, is continuous in the flue. It is possible to realize a more reliable light-scattering dust concentration meter for cloudy exhaust gas, which can be measured accurately and continuously for a long period of time.

It is a figure which shows the light scattering type dust densitometer which concerns on one Embodiment of this invention, and is the figure which shows the state attached to the flue. It is a figure which shows typically the principle of measuring the dust density | concentration in the cloudy exhaust gas by the light scattering type dust concentration meter which concerns on one Embodiment of this invention. It is sectional drawing which shows the light scattering type dust densitometer which concerns on one Embodiment of this invention. It is the X1-X1 line arrow view of FIG. It is the X2-X2 line arrow view of FIG. It is the X3-X3 line arrow view of FIG. It is a figure which shows the modification example of the light scattering type dust densitometer which concerns on one Embodiment of this invention.

Hereinafter, a light scattering type dust densitometer for cloudy exhaust gas according to an embodiment of the present invention will be described with reference to FIGS. 1 to 7. Here, in the present embodiment, the dust concentration in the cloudy exhaust gas, which is cloudy due to the adsorption and coexistence of mist and dust when the inside of the flue is below the dew point, is continuously, accurately and for a long period of time in the flue. It relates to a light scattering type dust densitometer for cloudy exhaust gas that can be continuously measured over a period of time.

As shown in FIGS. 1 and 2, the light scattering type dust densitometer (light scattering type dust densitometer for cloudy exhaust gas) A of the present embodiment has a flow direction T of the cloudy exhaust gas 2 in the flue 1. A vaporizer A1 is arranged on the upstream side, the mist 3 is vaporized by the vaporizer A1, the measurement light 4 is irradiated by the dust detection device A2 downstream of the vaporizer A1, and the scattered light 6 reflected by the dust 5 is detected. , It is configured to measure the dust concentration by the light scattering intensity.

Specifically, as shown in FIGS. 1, 2, and 3, the light scattering type dust densitometer A of the present embodiment takes in the cloudy exhaust gas 2 flowing through the flue 1 while maintaining its flow and becomes cloudy. A vaporizer A1 that vaporizes the mist 3 in the exhaust gas 2, a dust detection device A2 for measuring the dust concentration in the exhaust gas (2) after being vaporized by the vaporizer A1, a calculation device 7, and the first 1 The air blow mechanism 8, the second air blow mechanism 9, and the third air blow mechanism 10 are provided.

As shown in FIGS. 3 to 6 (and 2), the vaporizer A1 has an inner cylinder (heater pipe) formed in a cylindrical shape and arranged so that the axis O1 direction is aligned with the flow direction T of the cloudy exhaust gas 2. ) 11, a sheath heater 12 that is wound around the outer circumference of the inner cylinder 11, a heat transfer material 13 that covers the outer peripheral surface of the inner cylinder 11 so as to embed the sheath heater 12, the inner cylinder 11, the sheath heater 12, and heat transfer. A heat insulating material 14 arranged so as to include the material 13 and a first container 15 forming an outer shell of the vaporizer A1 and accommodating the inner cylinder 11, the sheath heater 12, the heat transfer material 13, and the heat insulating material 14 are provided. ing.

The inner cylinder 11 is formed by using a metal material such as a copper material having excellent thermal conductivity. In the present embodiment, the inner cylinder 11 is formed by combining a copper material and a nickel material, thereby realizing the inner cylinder 11 having extremely high thermal conductivity and excellent heat resistance and corrosion resistance.

As the sheath heater 12, for example, a 220 V / 600 W sheath heater 12 is wound around a plurality of inner cylinders 11 and used. Of course, one sheath heater 12 may be wound around the inner cylinder 11 to be configured.

The heat transfer material 13 is, for example, a heat transfer cement, and the heat generated by the sheath heater 12 is generated by covering the outer peripheral surface of the inner cylinder 11 with the heat transfer material 13 and burying the sheath heater 12 with the heat transfer material 13. Can be effectively propagated in the direction of the axis O1 of the inner cylinder 11 and effectively heated so that the entire inner cylinder 11 reaches a predetermined temperature. Further, by providing such a heat transfer material 13 (and a sheath heater 12, a heat insulating material 14), a large heat distribution does not occur in the entire inner cylinder 11, that is, the temperature distribution of the inner cylinder 11 becomes smaller. It becomes possible to heat (so as to be substantially uniform), and it becomes possible to efficiently heat the inner cylinder 11 to a high temperature of 500 ° C. or higher.

The heat insulating material 14 is a fiber-based heat insulating material having excellent heat resistance such as glass wool and rock wool, and a foam-based heat insulating material having excellent heat resistance such as phenol foam, and the fiber-based heat insulating material is particularly preferable.

In the first container 15 forming the outer shell of the vaporizer A1, the inner cylinder 11 has a plate surface orthogonal to the axis O1 of the inner cylinder 11 while communicating the inlet (entrance opening) 20 on one end side of the inner cylinder 11 to the outside. The plate surface is orthogonal to the axis O1 of the inner cylinder 11 while communicating the inlet side shielding plate portion 21 arranged on one end side of the inner cylinder 11 and the outlet (outlet opening) 22 on the other end side of the inner cylinder 11 to the outside. Both ends are joined to the outer peripheral surfaces of the outlet side shielding plate portion 23, the inlet side shielding plate portion 21 and the outlet side shielding plate portion 23 arranged on the other end side of the inner cylinder 11, and the inner cylinder 11 and the sheath heater 12 are joined. , A cover portion 24 arranged so as to surround the heat transfer material 13 and the heat insulating material 14, and an inlet side shield so as to accommodate the inner cylinder 11, the sheath heater 12, the heat transfer material 13, and the heat insulating material 14 together with the cover portion 24. The light scattering type dust densitometer A is fixed to the skeleton or the like formed by joining and arranging the plate portion 21 and the outer peripheral surface of the outlet side shielding plate portion 23 to form the flue 1, the sheath heater 12 and various air blow mechanisms 8 and 9. It is formed to include a board-shaped base portion 25 used for wiring such as 10 and the like, insertion and connection of pipes.

The inner cylinder 11, the sheath heater 12, the heat transfer material 13, and the heat insulating material 14 are housed in a sealed state by the inlet side shielding plate portion 21, the outlet side shielding plate portion 23, the cover portion 24, and the base portion 25.

In the present embodiment, a sealing agent such as a silicone sealant is applied to the joint portion of the inlet side shielding plate portion 21, the outlet side shielding plate portion 23, the cover portion 24, and the base portion 25. Further, as shown in FIG. 1, the base portion 25 is fixedly attached so as to seal the flue 1, so that the airtightness of the attachment hole 26a portion formed through the skeleton 26 or the like forming the flue 1 is airtight. Can be secured.

As shown in FIGS. 3 to 5, the inlet-side shielding plate portion 21 has a through-hole portion forming an inlet opening 20 on one end side of the inner cylinder 11 from the outer side in the radial direction centered on the axis O1 of the inner cylinder 11. It is formed as an inclined surface (tapered surface) 21a from the front surface where the entrance 20 gradually opens toward the inner surface on the rear side in the axis O1 direction toward the axis O1 side of the cylinder 11. As a result, the cloudy exhaust gas 2 can be smoothly introduced into the inner cylinder 11 from the inlet 20 on one end side of the inner cylinder 11.

In the first container 15 of the present embodiment, the inlet side shielding plate portion 21, the outlet side shielding plate portion 23, the cover portion 24, and the base portion 25 are formed of a resin material. As a result, the weight of the light scattering type dust densitometer A can be reduced, and even when exposed to the cloudy exhaust gas 2 for a long period of time, the cloudy exhaust gas 2 contains a corrosive substance such as hydrochloric acid. Even in this case, it is possible to form a container having excellent corrosion resistance and durability, which is less likely to cause corrosion or damage.

Further, by forming the inlet side shielding plate portion 21, the outlet side shielding plate portion 23, the cover portion 24, and the base portion 25 using a resin material, it is easy to replace the member when damage is caused by an impact or the like. It is possible to realize a light scattering type dust densitometer A that can be carried out and has excellent maintainability.

Further, it is preferable to use a fluororesin such as PTFE (polytetrafluoroethylene (tetrafluoroethylene resin)), PFA (perfluoroalkoxy alkane resin), PVDF (polyvinylidene fluoride) for the first container 15, and it is preferable to use a fluororesin. It is more preferable to use a resin material in which carbon is mixed with the resin. By using such a fluorine-based resin and a carbon-mixed fluorine-based resin, it becomes possible to more effectively form a container having excellent corrosion resistance and durability.

The first container 15 may be formed by using a metal material, for example, a stainless steel material such as SUS304, or a member obtained by coating a stainless steel material with a fluorine-based resin.

As shown in FIGS. 5 and 6, the first container 15 of the present embodiment is partially (upper end side) formed in an arc shape along the outer peripheral surface of the inner cylinder 11. On the other hand, as shown in FIG. 7, the first container 15 may be formed in a rectangular box shape (including a substantially rectangular box shape). When the first container 15 is formed in a rectangular box shape as shown in FIG. 7, the cover portion 24 can be easily attached, processed, replaced, etc., and further, the airtightness can be easily ensured. become.

In the vaporizer A1 of the present embodiment, for example, the inner cylinder 11 is heated to a high temperature of 500 ° C. or higher by providing the inner cylinder 11, the sheath heater 12, the heat transfer material 13, the heat insulating material 14, and the first container 15. can do. As shown in FIG. 3, a thermocouple 27 as a temperature measuring means is arranged inside the first container 15 in order to measure and control the temperature of the sheath heater 12 and the like.

Next, as shown in FIGS. 1 to 4 and 6, the dust detection device A2 is the exhaust gas 2 of the outlet opening 22 (outlet side shielding plate portion 23) on the other end side of the inner cylinder 11 of the vaporizer A1. It is included in the light irradiator 30 and the exhaust gas 2, which are provided adjacent to the downstream side of the flow direction T, vaporize the mist 3 by the vaporizer A1 and irradiate the exhaust gas 2 coming out of the outlet opening 22 with the light 4. A scattered light detector 31 that detects the scattered light 6 reflected by the dust 5 and a second container 32 that forms an outer shell of the dust detection device A2 and houses the light irradiator 30 and the scattered light detector 31 are provided. It is configured.

The second container 32 that forms the outer shell of the dust detection device A2 has a rectangular box shape (including a substantially rectangular box shape) that includes the light irradiator 30 and the scattered light detector 31 while sharing the base portion 25 of the first container 15. ) Is formed. Further, a circular through hole 32a is formed on the upper surface of the vaporizer A1 facing the exhaust gas 2 side immediately after exiting the outlet opening 22, and the light irradiator 30 and the scattered light detector 31 are held in the through hole 32a. The holding block 32b is fitted and provided.

Further, the holding block 32b is projected with the light 4 emitted from the light irradiator 30 inside the second container 32 toward the exhaust gas 2, and the scattered light 6 reflected by the dust 5 is projected inside the second container 32. A light transmitting member (transmissive surface: light projecting surface and light receiving surface) 32c for receiving light from the scattered light detector 31 of the above is provided. In this embodiment, a sealing material such as a holding block 32b and an O-ring 32d and a packing material are used to ensure a sealed state inside the second container 32.

The second container 32 of the present embodiment is formed by using a resin material like the first container 15. As a result, the weight of the light scattering type dust densitometer A can be reduced, and even when exposed to the cloudy exhaust gas 2 for a long period of time, the cloudy exhaust gas 2 contains a corrosive substance such as hydrochloric acid. Even in this case, it is possible to form a container having excellent corrosion resistance and durability, which is less likely to cause corrosion or damage. Further, by using the resin material, the member can be easily replaced when the member is damaged due to an impact or the like, and the light scattering type dust densitometer A having excellent maintainability can be realized.

Further, the second container 32, like the first container 15, is made of a fluororesin such as PTFE (polytetrafluoroethylene (tetrafluoroethylene resin)), PFA (perfluoroalkoxy alkane resin), PVDF (polyvinylidene fluoride). It is preferable to use it. Further, it is more preferable to use a composite resin material in which carbon (silicon carbide) is mixed with a fluororesin. By using such a fluorine-based resin and a carbon-mixed fluorine-based resin, it becomes possible to more effectively form a container having excellent corrosion resistance and durability.

Of course, the second container 32 may be formed by using a metal material as in the first container 15, and may be formed by using, for example, a member obtained by coating a stainless steel material such as SUS304 with a fluorine-based resin.

As shown in FIG. 3, the light irradiator 30 has a region S1 in which only dust 5 exists in an air curtain (air curtain described in detail later) 33 downstream of the flow direction T of the cloudy exhaust gas 2 with respect to the vaporizer A. A part of the scattered light detection area S2 is irradiated with the measurement light 4 for detecting the scattered light 6 which is the basis for measuring the dust concentration as diffused light. At that time, it is advisable to irradiate the measurement light 4 that has been synchronously detected at a constant wavelength.

The scattered light detector 31 detects the scattered light 6 scattered by reflecting the measurement light 4 on the dust 5 from which the mist 3 has been removed via the vaporizer A1.

Although the cloudy exhaust gas region S3 that has not passed through the vaporizer A1 is adjacent to the scattered light detection region S2 (region S1), the surrounding cloudy exhaust gas 2 is blocked by the air curtain 33 and vaporized by the vaporizer A1. By irradiating the exhaust gas 2 with the measurement light 4 which is not mixed with the exhaust gas 2 and is synchronously detected at a constant wavelength, the scattered light 6 scattered by the dust 5 in the scattered light detection region S2 and the vaporizer A1 are combined. The scattered light 6 having a different wavelength from the scattered light 6 scattered by the mist 3 and the mist adsorbed dust 5 in the cloudy exhaust gas 2 that has not passed through becomes a scattered light 6, and these can be identified by the scattered light detector 31.

Further, even if the scattered light 6 having the same wavelength as the scattered light 6 generated from the scattered light detection area S2 is generated from the adjacent or mixed cloudy exhaust gas 2 that has not passed through the vaporizer A1, the amount is extremely low. Further, since the light intensity of the scattered light detection region S2 is extremely strong, the amount of scattered light 6 from the cloudy exhaust gas 2 can be ignored.

Further, the inventor of the present application sets the intersection angle θ between the optical axis of the photodetector 30 and the optical axis of the scattered light detector 31 to 45 ° to 90 °, preferably 60 °, so that the exhaust gas vaporized by the vaporizer A is exhausted. It has been found that the dust 5 in 2 can be reliably and suitably detected by the dust detection device A2.

As shown in FIG. 1, the arithmetic unit 7 is an apparatus that calculates the dust concentration from the light intensity of the scattered light 6 based on the fact that the scattered light is in a proportional relationship with the dust concentration. For example, if a calibration curve having a proportional relationship between the dust concentration and the amount of light is created in advance, the dust concentration with respect to the amount of light of the detected scattered light 6 can be obtained from the calibration curve. The arithmetic unit 7 and the scattered light detector 31 may be integrated. In the present embodiment, the arithmetic unit 7 is configured to receive the scattered light intensity signal via the optical fiber.

On the other hand, as shown in FIGS. 3 and 5, the light scattering type dust densitometer A of the present embodiment includes a first air blow mechanism 8 that ejects intermittent air toward the inlet 20 side of the cloudy exhaust gas 2.

The first air blow mechanism 8 has a first flow path 8a for passing intermittent air through the inlet-side shielding plate portion 21 of the first container 15, and an inner surface on the rear side in the axis O1 direction from the front surface where the inlet 20 on one end side of the inner cylinder 11 opens. It is provided on the inclined surface (tapered surface) 21a of the inlet-side shielding plate portion 21 facing toward, and is provided with a large number of air discharge ports 8b through which the first flow path 8a communicates.

Then, when the first air blow mechanism 8 supplies the intermittent air to the first flow path 8a, the first air blow mechanism 8 ejects air from the plurality of air discharge ports 8b. By the air blow of the first air blow mechanism 8, the mist 3 condensed in the inlet 20 side portion (the through hole portion of the inlet side shielding plate portion 21) which is the intake port of the cloudy exhaust gas 2 can be dried or blown off. Further, since the inside of the through hole portion is formed as the inclined surface 21a, the mist 3 and the air blow flow from the first container 15 to the outside. As a result, it is possible to prevent the mist 3 from aggregating and accumulating drain on the inlet 20 side of the intake port of the cloudy exhaust gas 2 of the first container 15.

Next, as shown in FIGS. 3 and 6, the light scattering type dust densitometer A of the present embodiment has a region (air flow) S1 in which the mist 3 is maintained in a vaporized state through the vaporizer A1 and the vaporizer A1. A second air blow mechanism 9 for forming an air curtain 33 that separates and separates the cloudy exhaust gas region S3 that does not pass through is provided.

The second air blow mechanism 9 is provided in the outlet-side shielding plate portion 23 of the first container 15 and opens toward the second flow path 9a through which air is constantly passed and the outlet-side shielding plate portion 23 toward the downstream side in the flow direction T. It is provided with an air discharge port 9b that is formed along the outer peripheral end of the outlet-side shielding plate portion 23 and communicates with the second flow path 9a.

As a result, the second air blow mechanism 9 ejects air toward the downstream side of the flow direction T of the cloudy exhaust gas 2, and the region S1 in which the mist 3 is maintained in a vaporized state via the vaporizer A1 and the vaporizer A1. An air curtain 33 for separating and separating the cloudy exhaust gas 2 from the region S3, preventing the mist 3 from being mixed into the scattered light detection region S1 (S2), and detecting the scattered light 6 without the influence of the mist 3. Can be formed. That is, such an air curtain 33 can form an isolation space (S1) on the second container 32.

The air discharge port 9b is arranged along the outer peripheral end of the first container 15 up to the upper surface of the second container 32. At this time, the air discharge port 9b may be formed by interspersing a plurality of holes, or may be formed by extending one opening in a streak.

On the other hand, in the light scattering type dust densitometer A of the present embodiment, as shown in FIGS. 3 and 6, in addition to the above-mentioned first air blow mechanism 8 and second air blow mechanism 9, the translucent surface of the second container 32. A third air blow mechanism (air blow mechanism for a light transmitting surface) 10 for preventing drain accumulation due to condensation of mist 3, dust 5 adhering to the drain, accumulation, etc. is provided on the (light emitting surface, light receiving surface) 32c. I have.

The third air blow mechanism 10 is provided in the outlet-side shielding plate portion 23 of the first container 15 and allows air to pass through the second flow path 9a (10a) constantly or intermittently, and the flow direction of the outlet-side shielding plate portion 23. It opens toward the downstream side of T, and is formed along the width direction between the outlet opening 22 and the upper surface of the second container 32 below the outlet opening 22 of the outlet side shielding plate portion 23, and is a second flow path. It is provided with an air discharge port 10b that communicates with 9a (10a).

As a result, the third air blow mechanism 10 faces the downstream side of the flow direction T of the exhaust gas 2 and toward the light-transmitting surface 32c (above the light-transmitting surface) of the second container 32 inside the air curtain 33. By ejecting air to blow off the mist 3 and the like, it is possible to prevent (suppress) the accumulation of drain due to the condensation of the mist 3 and the adhesion and accumulation of dust 5 to the drain on the translucent surface 32c of the second container 32.

Here, as shown in FIGS. 1 and 3, the first air blow mechanism 8, the second air blow mechanism 9, and the third air blow mechanism 10 include an air supply source (not shown), an air supply source, and a first flow path 8a. A pipe 34 connecting the second flow path 9a (10a) and an electromagnetic valve provided in each pipe 34 are provided. Air is intermittently supplied to the first flow path 8a by controlling the opening and closing of the solenoid valve, and the solenoid valve is released to the second flow path 9a (10a) during normal measurement use other than maintenance. Air is always supplied.

Since the air blow by the first air blow mechanism 8 affects the dust detection value, the CPU records the dust detection value immediately before the air blow on the recording device in conjunction with the timing of the air blow, and displays the dust detection value on the display unit during the air blow. It is preferable to display it as the measured concentration so as not to affect the continuous instruction.

If the air blow by the third air blow mechanism 10 may affect the dust detection value as in the first air blow mechanism 8, the flow path 10a of the third air blow mechanism 10 may be provided independently, or the third air blow mechanism 10 may be provided independently. 1 The third air blow mechanism 10 is connected to the first flow path 8a of the air blow mechanism 8 or the pipe connected to the first flow path 8a of the first air blow mechanism 8 is connected to the flow path 10a of the third air blow mechanism 10. Air may be intermittently supplied to the flow path 10a to blow off the mist 3 and the like.

Therefore, in the light scattering type dust densitometer A of the present embodiment, the outlet 22 of the exhaust gas 2 of the vaporizer A1 is provided by providing the third air blow mechanism 10 in addition to the first air blow mechanism 8 and the second air blow mechanism 9. A mist 3 or a mist 3 or It is possible to prevent (suppress) the accumulation of dust 5 and the like.

Therefore, according to the light scattering type dust concentration meter A of the present embodiment, the dust concentration in the cloudy exhaust gas 2 in which the inside of the flue 1 is below the dew point and the mist 3 and the dust 5 are adsorbed and coexist and become cloudy. Can be continuously and accurately measured in the flue 1 for a long period of time, and a more reliable light scattering type dust densitometer A for the cloudy exhaust gas 2 can be realized.

Although one embodiment of the light scattering type dust densitometer according to the present invention has been described above, the present invention is not limited to the above one embodiment and can be appropriately changed without departing from the spirit of the present invention.

The light scattering dust densitometer of the present invention can be easily and inexpensively attached to an existing flue. In addition, only the dust in the cloudy exhaust gas below the dew point, which was difficult until now, is directly in the flue, and even if the flow of the cloudy exhaust gas is slow, it is continuous and accurate without being affected by other mists. Explaining evidence to residents who are worried that the standard value may be exceeded for cloudy exhaust gas because it is highly versatile and reliable because it is compatible with all flow velocities that can be continuously measured over a long period of time. Can be provided. Furthermore, it can also be used for white smoke prevention measures. Therefore, it can be expected to make a great contribution in the technical field and industry of exhaust gas measurement.

1 Flue 2 Cloudy exhaust gas 3 Mist 4 Measured light (light)
5 Dust 6 Scattered light 7 Arithmetic logic unit 8 1st air blow mechanism 9 2nd air blow mechanism (air blow mechanism for air curtain)
10 Third air blow mechanism (air blow mechanism for translucent surface)
10b Air discharge port 11 Inner cylinder 12 Sheath heater 13 Heat transfer material 14 Insulation material 15 First container 20 Inlet (inlet opening)
21 Entrance side shielding plate 22 Exit (outlet opening)
23 Outlet side shielding plate part 24 Cover part 25 Base part 26 Frame forming flue 26a Mounting hole 27 Thermocouple 30 Photoirradiator 31 Scattered light detector 32 Second container 32c Translucent member (translucent surface: light projecting surface) And the light receiving surface)
33 Air curtain A Light scattering type dust concentration meter for cloudy exhaust gas A1 Vaporizer A2 Dust detector O1 Axis of inner cylinder S1 Region where mist is maintained in a vaporized state through the vaporizer (region where mist is vaporized)
S2 Scattered light detection area S3 White turbid exhaust gas area that has not passed through the vaporizer T Flow direction of cloudy exhaust gas

Claims (3)

A dust densitometer for cloudy exhaust gas for directly detecting dust in the cloudy exhaust gas in which mist and dust are adsorbed and coexisting in the flue and measuring the dust concentration.
A vaporizer that is arranged in the flue and takes in the cloudy exhaust gas to be measured and vaporizes the mist.
A dust detection device including a photoirradiator that irradiates a region where the mist is vaporized with light, and a scattered light detector that detects the scattered light that the light is reflected on the dust.
From the outlet side of the exhaust gas that vaporized the mist of the vaporizer, toward the side of the translucent surface that causes the light emitted by the light irradiator to be projected onto the region where the mist is vaporized, and the dust. An air blow mechanism for the translucent surface that ejects air toward the translucent surface that receives the scattered light reflected by the scattered light detector.
A first air blow mechanism for ejecting intermittent air to the inlet side of the cloudy exhaust gas in the vaporizer is provided.
The flow path of the first air blow mechanism includes an electromagnetic valve for intermittently supplying air by opening / closing control.
The flow path of the air blow mechanism for the translucent surface is a light scattering type dust densitometer for cloudy exhaust gas that communicates with the flow path of the first air blow mechanism on the downstream side of the solenoid valve. An air curtain that separates the region where the mist is maintained in a vaporized state through the vaporizer from the cloudy exhaust gas that does not pass through the vaporizer is provided from the outlet side of the exhaust gas of the vaporizer to the downstream in the flow direction of the exhaust gas. Equipped with an air blow mechanism for the air curtain formed in
The air blow mechanism for the translucent surface is
An air discharge port for ejecting air is provided in a region in the air curtain where the mist is maintained in a vaporized state through the vaporizer.
The air is directed to the side of the translucent surface provided in a region where the mist is maintained in a vaporized state through the vaporizer in the air curtain on the downstream side in the flow direction of the exhaust gas from the air discharge port. The light scattering type dust densitometer for cloudy exhaust gas according to claim 1, which is configured to eject. The cloudy exhaust gas according to claim 2, wherein the air discharge port is provided between the outlet of the exhaust gas and the translucent surface in the vertical direction when viewed from the downstream side in the flow direction of the exhaust gas. Light scattering dust densitometer for.

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