WO2021171856A1

WO2021171856A1 - Dust collector

Info

Publication number: WO2021171856A1
Application number: PCT/JP2021/002344
Authority: WO
Inventors: 幸平村上
Original assignee: 富士電機株式会社
Priority date: 2020-02-25
Filing date: 2021-01-22
Publication date: 2021-09-02
Also published as: CN114144260A; EP3991850A4; KR20220020991A; EP3991850A1; JP7243915B2; JPWO2021171856A1

Abstract

Provided is a dust collector comprising a dust collection part for collecting particles, a microwave generation part for generating microwaves to be introduced into the dust collection part and burning the particles collected in the dust collection part by the microwaves, and an intensity detection part for detecting the intensity of the microwaves unabsorbed by the particles, wherein the microwave generation part controls the intensity of the microwaves to be introduced into the dust collection part on the basis of the intensity of the microwaves detected by the intensity detection part. The intensity detection part may be provided with: a derivation part for deriving at least a portion of the microwaves unabsorbed by the particles from the dust collection part; a microwave absorber for absorbing the microwaves derived from the dust collection part; and a temperature detection part for detecting the temperature of the microwave absorber.

Description

Dust collector

The present invention relates to a dust collector.

Conventionally, an electrostatic precipitator that "burns charged particles collected in a dust collecting portion by microwaves" is known (see, for example, Patent Document 1). Further, there are known devices that detect the amount of microwave energy from the temperature of a radio wave absorber that absorbs microwaves (see, for example, Patent Documents 2 and 3).
Patent Document 1 PCT / JP2019 / 35325
Patent Document 2 Japanese Patent Application Laid-Open No. 5-172884 Patent Document 3 Japanese Patent Application Laid-Open No. 5-52889

The problem to be solved

In the dust collector, it is preferable to reduce energy consumption.

General disclosure

In order to solve the above problems, in one aspect of the present invention, a dust collector is provided. The dust collector may include a dust collector that collects particles. The dust collector may include a microwave generating unit that generates microwaves to be introduced into the dust collecting unit and burns the particles collected in the dust collecting unit by the microwaves. The dust collector may include an intensity detector that detects the intensity of microwaves that have not been absorbed by the particles. The microwave generating unit may control the intensity of the microwave introduced into the dust collecting unit based on the intensity of the microwave detected by the intensity detecting unit.

The intensity detection unit may have a derivation unit that derives at least a part of microwaves that have not been absorbed by the particles from the dust collection unit. The intensity detecting unit may have a microwave absorber that absorbs microwaves derived from the dust collecting unit. The intensity detection unit may have a temperature detection unit that detects the temperature of the microwave absorber.

The microwave generator is a microwave generator that is introduced into the dust collector when the temperature of the microwave absorber becomes higher than the first reference temperature while the first intensity microwave is introduced into the dust collector. The strength may be switched to a second strength that is lower than the first strength.

The microwave generator is a microwave generator that is introduced into the dust collector when the temperature of the microwave absorber becomes lower than the second reference temperature while the second intensity microwave is introduced into the dust collector. The strength may be switched to the first strength.

The dust collector may be provided with a flame detection unit that detects that a flame has been generated in the dust collection unit. When a flame is generated, the microwave generating unit may reduce the intensity of the microwave introduced into the dust collecting unit, or may stop the introduction of the microwave into the dust collecting unit.

The dust collector is a calculation unit that calculates the amount of combustible particles accumulated in the dust collector based on the integrated time in which the microwave generator introduces the first-intensity microwave into the dust collector. May be equipped.

The dust collector may include a calculation unit that calculates the amount of particles introduced into the dust collection unit based on the slope of the rising waveform in the time waveform of the temperature detected by the temperature detection unit.

The intensity detection unit may store in advance the relationship between the temperature of the microwave absorber and the intensity of the microwave when the microwave is introduced into the dust collection unit in the state where no particles are present in the dust collection unit. The intensity detecting unit may detect the intensity of the microwave not absorbed by the particles from the temperature of the microwave absorber when the microwave is introduced into the dust collecting unit in the state where the particles are present in the dust collecting unit. ..

The dust collector is a calculation unit that calculates the intensity of microwaves absorbed by particles from the difference between the intensity of microwaves detected by the intensity detector and the intensity of microwaves introduced into the dust collector by the microwave generator. May be equipped.

The calculation unit may calculate the amount of combustible particles remaining in the dust collection unit based on the time integral value of the intensity of the microwave absorbed by the particles.

Derivation units may be provided at a plurality of derivation positions of the dust collection unit. The microwave absorber may absorb microwaves in which microwaves derived from a plurality of out-licensing units are combined.

The microwave generating unit may introduce microwaves into the dust collecting unit from a plurality of introduction positions of the dust collecting unit. The microwave absorber may be provided at each derivation position. The microwave generator may control the intensity of the microwave introduced from the corresponding introduction position based on the temperature of the microwave absorber at each lead-out position.

Exhaust gas emitted by the exhaust gas source may be introduced into the dust collector. When a flame is generated, the microwave generating unit may control the intensity of the microwave introduced into the dust collecting unit based on the operating state of the exhaust gas source.

The outline of the above invention does not list all the necessary features of the present invention. Sub-combinations of these feature groups can also be inventions.

It is a block diagram which shows the structural example of the dust collector 100 which concerns on one Embodiment of this invention. It is a schematic diagram which shows an example of the dust collecting part 120. It is a figure which shows an example of the structure of a partition wall 32. It is a figure which shows an example of the YZ cross section of the dust collecting part 120 at the position X1 in the X-axis direction in FIG. It is a figure which shows an example of the time waveform of the temperature of the microwave absorber 144, and the time waveform of the intensity of the microwave introduced by the microwave generation part 130 into the dust collecting part 120. It is a figure which shows the other structural example of the dust collector 100. It is a figure which shows the other structural example of the dust collector 100. It is a figure which shows the arrangement example of the microwave generation part 130 and the intensity detection part 140.

Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the inventions claimed. Also, not all combinations of features described in the embodiments are essential to the means of solving the invention.

FIG. 1 is a block diagram showing a configuration example of a dust collector 100 according to an embodiment of the present invention. The dust collector 100 collects particles contained in a target gas such as exhaust gas. In this specification, the target gas will be described as an exhaust gas. Exhaust gas may be introduced into the dust collector 100 from the exhaust gas source 200. The exhaust gas source 200 is, for example, an engine of a ship or the like. In this case, the dust collector 100 may be provided on the ship.

The exhaust gas introduced into the dust collector 100 includes particles such as nitrogen oxides (NOx), sulfur oxides (SOx), and particulate matter (PM: Particulate Matter). Particulate matter (PM), also known as black carbon, is generated by incomplete combustion of fossil fuels. Particulate matter (PM) is fine particles containing carbon as a main component.

The dust collector 100 may collect the charged particles charged with the target particles. That is, the dust collector 100 may be an electrostatic precipitator. The dust collector 100 burns the collected charged particles by microwaves. As a result, it is possible to suppress excessive accumulation of the collected charged particles and continuously treat the exhaust gas.

The dust collector 100 of this example includes a charging unit 110, a dust collecting unit 120, a microwave generating unit 130, an intensity detecting unit 140, and a control unit 150. Exhaust gas is introduced into the charged portion 110. For example, the charging unit 110 generates ions by corona discharge in a space through which exhaust gas passes to charge the target particles. The exhaust gas containing the charged particles is sent to the dust collecting unit 120.

The dust collecting unit 120 collects charged particles. The dust collecting unit 120 collects charged particles by Coulomb force by arranging a member to which a ground potential or the like is applied in a path through which the exhaust gas passes, for example. The dust collecting unit 120 discharges the exhaust gas after collecting the charged particles.

The microwave generating unit 130 generates microwaves and introduces them into the dust collecting unit 120. A microwave is an electromagnetic wave having a frequency of, for example, 300 MHz to 300 GHz.

The dust collector 100 of this example burns the charged particles collected by the dust collecting unit 120 by the microwave generated by the microwave generating unit 130. The microwave introduced into the dust collecting unit 120 is absorbed by the charged particles, so that the charged particles are heated. The charged particles can be burned by introducing microwaves to such an extent that the temperature of the charged particles becomes equal to or higher than the ignition point. Generally, the heating rate Q of the object to be heated by the microwave is expressed by the following formula.
Q = (1/2) σ | E | ² + (1/2) ωε'' | E | ² + (1/2) ωμ'' | B | ²

The first term (1/2) σ | E | ² indicates the heating rate due to Joule heating by an electric field. Here, σ is the conductivity of the fine particles contained in the object to be heated. Further, E is an electric field generated by microwaves. The application of an electric field to the object to be heated results in charge transfer in the object to be heated. This charge transfer, or current, results in Joule loss. The first term represents heat generation due to this Joule loss.

The second term (1/2) ωε'' | E | ² indicates the heating rate due to dielectric heating by an electric field. Here, ω is the angular frequency of the microwave, and ε'' is the imaginary part of the permittivity of the object to be heated. When an electric field is applied to the object to be heated, the electric dipole contained in the object to be heated follows the change in the electric field with a time delay. The time-lagging follow-up of this electric dipole results in loss. The second term represents heat generation due to this loss.

The third term (1/2) ωμ'' | B | ² indicates the heating rate due to Joule heating by eddy current. Here, μ'' is an imaginary part of the magnetic permeability of the object to be heated. When a magnetic field is applied to the object to be heated, an eddy current is generated in a direction that hinders the change in the magnetic field. This eddy current results in Joule loss. The third term represents heat generation due to this Joule loss.

The dust collecting unit 120 may have an antenna that irradiates the internal collecting space with microwaves. By burning the charged particles using microwaves, the target particles can be removed with a simple and space-saving structure as compared with methods such as hammering, air cleaning, and water cleaning.

Of the microwaves introduced into the dust collector 120, some components are absorbed by the charged particles, and the remaining components remain without being absorbed by the charged particles. When microwaves having an excessive intensity compared to the amount of charged particles collected in the dust collecting unit 120 are introduced, microwaves that cannot be completely absorbed by the charged particles remain. The intensity detecting unit 140 detects the intensity of the microwaves introduced into the dust collecting unit 120 that are not absorbed by the charged particles. This makes it possible to determine whether or not the microwave intensity is excessive.

The microwave generating unit 130 controls the intensity of the microwave introduced into the dust collecting unit 120 based on the intensity of the microwave detected by the intensity detecting unit 140. In this example, the control unit 150 generates a control signal for controlling the intensity of the microwave in the microwave generation unit 130. The control unit 150 may reduce the intensity of the microwave introduced by the microwave generating unit 130 into the dust collecting unit 120 as the intensity of the microwave detected by the intensity detecting unit 140 increases. The control unit 150 may reduce the intensity of the microwave introduced by the microwave generating unit 130 into the dust collecting unit 120 when the intensity of the microwave detected by the intensity detecting unit 140 exceeds a predetermined threshold value. According to the dust collector 100 of this example, the intensity of the microwave introduced into the dust collector 120 can be appropriately controlled to suppress energy consumption.

The intensity detection unit 140 of this example has a lead-out unit 142, a microwave absorber 144, and a temperature detection unit 146. The extraction unit 142 derives at least a part of the microwaves that have not been absorbed by the charged particles inside the dust collection unit 120 from the dust collection unit 120. The lead-out unit 142 may have a circulator that allows microwaves in the direction exiting the dust collection unit 120 to pass through and shields the microwaves in the direction toward the dust collection unit 120. The higher the intensity of the microwave remaining inside the dust collecting unit 120, the higher the intensity of the microwave derived by the out-licensing unit 142. Therefore, from the intensity of the microwave derived by the extraction unit 142, the intensity of the microwave not absorbed by the charged particles inside the dust collecting unit 120 can be detected.

The microwave absorber 144 absorbs the microwave derived from the dust collector 120. The microwave absorber 144 contains a substance that generates heat by absorbing microwaves. The microwave absorber 144 may contain water and may contain a ceramic such as silicon carbide or aluminum oxide.

The temperature detection unit 146 detects the temperature of the microwave absorber 144. The temperature detection unit 146 includes, for example, a sensor such as a thermoelectric pair provided in contact with the microwave absorber 144. The temperature detection unit 146 of this example notifies the control unit 150 of information indicating the temperature of the microwave absorber 144. As described above, the control unit 150 controls the microwave generation unit 130 based on the information. It can be seen that the higher the temperature of the microwave absorber 144, the higher the intensity of the microwave that was not absorbed by the charged particles.

FIG. 2 is a schematic view showing an example of the dust collecting unit 120. FIG. 2 schematically shows a perspective view of the dust collecting unit 120. The shape of the dust collecting portion 120 in this example is cylindrical, but it may be another shape such as a box shape.

The dust collecting unit 120 of this example has an opening 42 for supplying exhaust gas, a gas flow path 44 for flowing exhaust gas, and an opening 46 for discharging exhaust gas. The exhaust gas supplied to the opening 42 contains charged particles charged by the charging unit 110. The gas flow path 44 has a partition wall 32 that surrounds a space through which gas flows. The partition wall 32 may have a tubular shape. The charged particles are removed from the exhaust gas in the gas flow path 44. The exhaust gas from which the charged particles have been removed is discharged from the opening 46.

The dust collecting unit 120 has a charged particle accumulating unit 36 for accumulating charged particles. The charged particle accumulating portion 36 of this example has a partition wall 32, a space 41, and an outer wall 39 in the YZ plane. The space 41 is arranged outside the partition wall 32. The outer wall 39 is arranged outside the space 41 in the YZ plane. The outer wall 39 may have a tubular shape. Further, the partition wall 32 is provided with an opening (described later) for passing charged particles. The partition wall 32 and the outer wall 39 may be made of a metal material.

A potential capable of electrically attracting charged particles is applied to the outer wall 39. The potential applied to the outer wall 39 may be the ground potential. The charged particles contained in the exhaust gas passing through the gas flow path 44 pass through the opening (described later) of the partition wall 32 and adhere to the outer wall 39 or the like of the charged particle accumulating portion 36. By introducing microwaves into the space 41, charged particles adhering to the outer wall 39 and the like can be burned.

The outer wall 39 of this example has an opening 48 for introducing the microwave generated by the microwave generating unit 130 or deriving the microwave from the dust collecting unit 120. In this example, the traveling direction of the exhaust gas in the dust collecting unit 120 is defined as the X-axis. Let the two orthogonal axes on the plane perpendicular to the X axis be the Y axis and the Z axis. A plurality of openings 48 may be arranged along the X-axis direction. Further, a plurality of openings 48 may be arranged along the outer periphery of the outer wall 39 on the YZ surface. The opening 48 may be provided so as to penetrate the outer wall 39. In the example of FIG. 2, two openings 48 are arranged so as to sandwich the gas flow path 44 in the Y-axis direction.

The dust collecting unit 120 has reflecting units 34 for reflecting microwaves at both ends of the charged particle accumulating unit 36 in the X-axis direction. Reflecting portions 34 provided at one end and the other end in the X-axis direction may be provided so as to surround the space 41 in the YZ plane. The microwave introduced from the opening 48 propagates through the charged particle accumulating portion 36 and is reflected by the reflecting portion 34 to form a traveling wave or a standing wave in the charged particle accumulating portion 36. The traveling direction of the microwave is not limited to the direction parallel to the X-axis. Microwaves can form traveling or standing waves in various directions, such as the circumferential direction on the YZ plane of space 41.

The dust collecting unit 120 has a first electrode 30 and a second electrode. The first electrode 30 may be arranged along the central axis of the dust collecting portion 120. The first electrode 30 may have a rod shape having a length on the X-axis. The first electrode 30 may be continuously provided along the X-axis direction from the opening 42 to the opening 46. The second electrode may be arranged around the first electrode 30 in the YZ plane. In this example, the partition wall 32 functions as a second electrode. The partition wall 32 may have a tubular shape that accommodates the first electrode 30. The first electrode 30 may be arranged at the center of the region surrounded by the partition wall 32 on the YZ surface. In the YZ plane, the gas flow path 44 may be sandwiched between the first electrode 30 and the partition wall 32.

In this example, the microwave generation unit 130 introduces microwaves into a plurality of openings 48. The microwave generation unit 130 may introduce microwaves of the same intensity into the plurality of openings 48. In another example, the microwave generator 130 may be able to control the intensity of the microwave for each opening 48.

The intensity detection unit 140 detects the intensity of microwaves derived from the plurality of openings 48. The intensity detection unit 140 may detect the intensity by collecting microwaves derived from the plurality of openings 48. Microwaves derived from each aperture 48 may be introduced into a common waveguide. The intensity detection unit 140 may detect the intensity of microwaves in the common waveguide.

In the example of FIG. 2, the microwave generation unit 130 and the intensity detection unit 140 are provided in different openings 48. In another example, the microwave generation unit 130 and the intensity detection unit 140 may be provided in the common opening 48. In this case, the intensity detection unit 140 detects the intensity of the microwave from the opening 48 toward the microwave generation unit 130.

FIG. 3 is a diagram showing an example of the configuration of the partition wall 32. In FIG. 3, the partition wall 32 is shown by hatching. Further, in FIG. 3, the outer wall 39 is shown by a broken line. The partition wall 32 has an opening 38 through which charged particles pass. The opening 38 is a through hole connecting the space 41 and the gas flow path 44. A plurality of openings 38 may be provided. The openings 38 may be provided periodically in the X-axis direction and in the YZ plane.

The position of the opening 38 and the position of the opening 48 may be different in the X-axis direction. When the dust collecting portion 120 is viewed from the + Y-axis direction to the −Y-axis direction, the opening 48 and the partition wall 32 may overlap, and the opening 48 and the opening 38 do not have to overlap. When the dust collector 120 is viewed from the + Y-axis direction to the −Y-axis direction, a part of the opening 48 may overlap with a part of the opening 38.

FIG. 4 is a diagram showing an example of a YZ cross section of the dust collecting portion 120 at the position X1 in the X-axis direction in FIG. The cross section is a YZ plane passing through an opening 48, a first electrode 30, a gas flow path 44, a partition wall 32, an opening 38, a space 41 and an outer wall 39.

The partition wall 32 is provided so as to surround the gas flow path 44. The first electrode 30 is provided at the center position of the cross section of the gas flow path 44. The partition wall 32 is provided with an opening 38. A space 41 is provided on the outside of the partition wall 32. The space 41 is surrounded by an outer wall 39. The outer wall 39 and the partition wall 32 may be provided concentrically around the first electrode 30. The outer wall 39 is provided with an opening 48 for introducing or deriving microwaves.

The first electrode 30 may be set to a predetermined high potential of direct current with respect to the ground potential. The predetermined high potential may be 10 kV or more. The partition wall 32 (second electrode) and the outer wall 39 may be grounded. A predetermined high voltage (for example, 10 kV or more) of direct current is applied between the first electrode 30 and the partition wall 32.

When a predetermined high voltage of direct current is applied between the first electrode 30 and the partition wall 32 (second electrode), a corona discharge occurs in the gas flow path 44 between the first electrode 30 and the partition wall 32. As a result, the particles contained in the gas flowing through the gas flow path 44 are charged. The charged particles 28 are attracted to the partition wall 32 and the outer wall 39, pass through the opening 38, and move into the space 41.

The microwave generation unit 130 introduces microwaves from the opening 48. The microwave generation unit 130 and the opening 48 may be connected by a waveguide 131. The microwave introduced from the opening 48 propagates mainly in the space 41 and is absorbed by the charged particles 28. When the amount of the charged particles 28 in the space 41 is small, the microwaves absorbed by the charged particles 28 are small, so that the microwaves remaining in the space 41 are large.

The derivation unit 142 derives at least a part of the microwave remaining in the space 41 from the opening 48. The opening 48 and the lead-out unit 142 may be connected by a waveguide 131. The derivation unit 142 introduces the derived microwave into the microwave absorber 144. The lead-out unit 142 and the microwave absorber 144 may be connected by a waveguide 131. The lead-out unit 142 may have a circulator that shields microwaves from the waveguide 131 on the microwave absorber 144 side toward the opening 48. The microwave absorber 144 absorbs the introduced microwave and generates heat. The higher the temperature of the microwave absorber 144, the higher the intensity of the microwave that was not absorbed by the charged particles. With such a configuration, the intensity of excess microwaves that are not absorbed by the charged particles 28 can be detected.

In the example of FIG. 4, the microwave generation unit 130 and the lead-out unit 142 are connected to the two openings 48 arranged to face each other on the YZ surface. The arrangement of the two openings 48 to which the microwave generation unit 130 and the lead-out unit 142 are connected is not limited to the example of FIG. The two openings 48 to which the microwave generation unit 130 and the lead-out unit 142 are connected may be arranged at different positions in the X-axis direction.

Further, as shown in FIG. 2, the lead-out unit 142 and the microwave absorber 144 may be provided in common with respect to the plurality of openings 48. As a result, even when the microwaves remain unevenly in the space 41, the intensity of the microwaves in the space 41 can be averaged and detected.

FIG. 5 is a diagram showing an example of a time waveform of the temperature of the microwave absorber 144 and a time waveform of the intensity of the microwave introduced by the microwave generating unit 130 into the dust collecting unit 120. In the example of FIG. 5, the time when the microwave generating unit 130 is started is set to 0.

At startup, the microwave generation unit 130 generates microwaves of the first intensity P1. If the amount of the charged particles 28 in the space 41 is relatively small, the microwaves of the first intensity P1 cannot be completely absorbed by the charged particles 28, and the microwaves are introduced into the microwave absorber 144. As a result, the temperature of the microwave absorber 144 rises.

When the temperature of the microwave absorber 144 becomes equal to or higher than the first reference temperature C1 (time t1) in a state where the microwave of the first intensity P1 is introduced into the dust collector 120, the microwave generating unit 130 is used. , The intensity (watt) of the microwave introduced into the dust collecting unit 120 is switched to the second intensity P2, which is lower than the first intensity P1. The second intensity P2 may be 80% or less, 50% or less, or 0% of the first intensity P1. Further, when the temperature of the microwave absorber 144 becomes equal to or higher than the first reference temperature C1, the microwave generating unit 130 gradually reduces the intensity of the microwave until the temperature of the microwave absorber 144 begins to decrease. You may let me. As an example, the first intensity P1 is in the range of 450W to 550W, and the second intensity P2 is in the range of 350W to 450W.

When the intensity of the microwave becomes the second intensity P2 and most of the microwave introduced into the space 41 is absorbed by the charged particles 28, the microwave introduced into the microwave absorber 144 becomes smaller or becomes smaller. Almost disappear. As a result, the temperature of the microwave absorber 144 is lowered.

When the temperature of the microwave absorber 144 becomes equal to or lower than the second reference temperature C2 (time t2) in a state where the microwave of the second intensity P2 is introduced into the dust collector 120, the microwave generating unit 130 is used. , The intensity of the microwave introduced into the dust collecting unit 120 is switched to the first intensity P1. When the temperature of the microwave absorber 144 becomes equal to or lower than the second reference temperature C2, it can be determined that the intensity of the microwave introduced into the space 41 is less than the amount of the charged particles 28 in the space 41. Therefore, by switching the microwave intensity to the first intensity P1, the charged particles 28 in the space 41 can be easily burned. Further, the microwave generation unit 130 may gradually increase the intensity of the microwave until the temperature of the microwave absorber 144 starts to increase.

By repeating such processing, the microwave can be adjusted to the intensity according to the amount of charged particles 28 in the space 41. Therefore, it is possible to save microwave energy while preventing the charged particles 28 from remaining without burning.

FIG. 6 is a diagram showing another configuration example of the dust collector 100. The dust collector 100 of this example includes a calculation unit 152 in addition to the configuration of the dust collector 100 described with reference to FIGS. 1 to 5. Other configurations are the same as the dust collector 100 described with reference to FIGS. 1 to 5.

In the calculation unit 152, the combustibles of the charged particles 28 are accumulated in the dust collection unit 120 based on the integrated time in which the microwave generation unit 130 introduces the microwave of the first intensity P1 into the dust collection unit 120. The amount may be calculated. That is, the calculation unit 152 calculates the accumulated amount of combustibles based on the cumulative time of the period T2 shown in FIG. Since the charged particles 28 are mainly burned during the period T2 where the microwave intensity is high, the combustion amount of the charged particles 28 can be estimated by accumulating the period T2. The calculation unit 152 may calculate the accumulated amount of combustibles based on the cumulative time of the period T1 shown in FIG. The period T1 is a period from when the temperature of the microwave absorber 144 becomes equal to or lower than the second reference temperature C2 until the temperature reaches the first reference temperature C1.

The intensity detection unit 140 may calculate the intensity of the microwave remaining without being absorbed by the charged particles 28 from the temperature of the microwave absorber 144. The temperature of the microwave absorber 144 varies depending on the intensity of the microwave. The intensity detection unit 140 may acquire in advance the relationship between the temperature of the microwave absorber 144 and the intensity of the microwave when the microwave is introduced into the space 41 in the state where the charged particles 28 are not present in the space 41. As a result, the temperature-intensity relationship with the intensity of the residual microwave in the space 41 can be acquired from the temperature of the microwave absorber 144 and stored in advance in the intensity detection unit 140. The intensity detection unit 140 acquires the temperature of the microwave absorber 144 when the microwave is introduced into the space 41 in the state where the charged particles 28 are present in the space 41. The intensity detection unit 140 may derive the intensity of the residual microwave corresponding to the temperature from the temperature-intensity relationship described above.

The calculation unit 152 may calculate the intensity of the microwave absorbed by the charged particles 28 from the difference between the intensity of the residual microwave and the intensity of the microwave introduced into the dust collecting unit 120. Further, the calculation unit 152 may calculate the amount of combustibles remaining in the space 41 based on the time integral value of the intensity of the microwave absorbed by the charged particles 28. The relationship between the time integral value of the intensity of the absorbed microwave and the amount of combustibles may be obtained experimentally in advance.

When the amount of combustibles remaining in the space 41 exceeds a predetermined reference value, the calculation unit 152 may notify the user to that effect. This makes it easier to grasp the cleaning time of the dust collecting unit 120.

The calculation unit 152 may calculate the amount of particles introduced into the dust collecting unit 120 based on the slope of the rising waveform in the time waveform of the temperature detected by the temperature detecting unit 146. The calculation unit 152 detects the slope of the rising waveform 147 shown in FIG. Since the difference between the first reference temperature C1 and the second reference temperature C2 is known, the calculation unit 152 may detect the period T1 shown in FIG. 5 as the slope of the rising waveform 147. The smaller the amount of the charged particles 28 introduced into the dust collecting unit 120, the smaller the microwaves absorbed by the charged particles 28. Further, when the amount of the charged particles 28 is small, the heat insulating and heat retaining effect of the charged particles 28 itself becomes small. Therefore, heat dissipation from the charged particles 28 becomes dominant with respect to heat input to the charged particles 28 due to microwave absorption. As a result, the slope of the rising waveform 147 becomes small. The relationship between the slope of the rising waveform 147 and the amount of charged particles 28 can be obtained experimentally in advance.

The microwave generation unit 130 may control the first intensity P1 based on the slope of the rising waveform 147. For example, when the slope of the rising waveform 147 is small, it is estimated that the amount of charged particles 28 is small. In the microwave generation unit 130, the smaller the slope of the rising waveform 147, the larger the first intensity P1 may be. Thereby, the first intensity P1 of the microwave can be adjusted according to the amount of the charged particles 28.

FIG. 7 is a diagram showing another configuration example of the dust collector 100. The dust collector 100 of this example includes a flame detection unit 160 in addition to the configuration of the dust collector 100 described with reference to FIGS. 1 to 6. The other configuration is the same as the dust collector 100 of any aspect described with reference to FIGS. 1 to 6. FIG. 7 illustrates a configuration in which a flame detection unit 160 is added to the configuration shown in FIG.

The flame detection unit 160 detects that a flame has occurred in the space 41 of the dust collection unit 120. The charged particles 28 burn without generating a flame like charcoal by absorbing microwaves, but may generate a flame. For example, a flame may be generated in the space 41 due to reasons such as the intensity of microwaves being too strong, the amount of charged particles 28 being too small, or the exhaust gas containing a large amount of oil. For example, when a gasoline engine is driven with a low load, the exhaust gas may contain a large amount of oil. The flame detection unit 160 may detect a flame by detecting a wavelength component of light generated when the flame is generated. The flame detection unit 160 may detect the flame based on other parameters such as the amount of light and the temperature in the space 41.

When a flame is generated in the space 41, the microwave generating unit 130 reduces the intensity of the microwave introduced into the dust collecting unit 120, or stops the introduction of the microwave into the dust collecting unit 120. When a flame is generated, the microwave generating unit 130 may reduce the intensity of the microwave introduced into the dust collecting unit 120 to the second intensity P2, or may decrease the intensity to less than the second intensity P2, and the intensity may be reduced. May be 0. As a result, the dust collecting unit 120 can be protected.

The microwave generating unit 130 may control the intensity of the microwave introduced into the dust collecting unit 120 based on the operating state of the exhaust gas source 200 when a flame is generated. For example, the cause of the flame may differ depending on the operating state of the exhaust gas source 200. When the exhaust gas source 200 is in a low load state, for example, and the exhaust gas contains a large amount of oil, there is a high possibility that a flame is generated due to the oil content. In this case, the amount of charged particles 28 introduced into the space 41 is likely to be normal. On the other hand, when the exhaust gas source 200 is in a normal load state, it is highly possible that the microwave intensity is too high compared to the amount of charged particles 28 introduced into the space 41. The microwave generation unit 130 may reduce the intensity of microwaves when a flame is generated when the exhaust gas source 200 is in a normal load state, as compared with a case where a flame is generated when the exhaust gas source 200 is in a low load state. This makes it easier to control the intensity of microwaves according to the amount of charged particles 28.

The microwave generating unit 130 may restart the introduction of the microwave into the dust collecting unit 120 when the flame is extinguished. In the microwave generation unit 130, the intensity of the microwave at the time of resuming the introduction may be set to the first intensity P1 or lower than the first intensity P1.

Further, the dust collector 100 may include a plurality of dust collectors 120. In this case, the dust collector 100 may stop the introduction of the exhaust gas and the introduction of the microwave into the dust collecting unit 120 in which the flame is detected. The dust collector 100 may treat the exhaust gas by the dust collector 120 in which no flame is detected.

FIG. 8 is a diagram showing an arrangement example of the microwave generation unit 130 and the intensity detection unit 140. The microwave generation unit 130 of this example is provided for each of the plurality of openings 48 with respect to the plurality of openings 48. As a result, the microwave generation unit 130 introduces the microwave into the dust collection unit 120 from the plurality of introduction positions of the dust collection unit 120.

Further, the strength detection unit 140 is provided for each of the plurality of openings 48 with respect to the plurality of openings 48. As a result, the intensity detection unit 140 derives microwaves from the plurality of extraction positions of the dust collection unit 120. Each intensity detection unit 140 has the structure shown in FIG. That is, a lead-out unit 142, a microwave absorber 144, and a temperature detection unit 146 are provided for each opening 48.

Each microwave generation unit 130 controls the intensity of the microwave introduced into the corresponding opening 48 based on the intensity of the microwave detected by any of the intensity detection units 140. Each microwave generation unit 130 may control the microwave intensity based on the detection result of the intensity detection unit 140 provided at the derivation position closest to the self-introduction position. Further, each microwave generation unit 130 may control the microwave intensity based on the detection result of the intensity detection unit 140 provided at the same derivation position as the self-introduction position and the position in the X-axis direction. good.

The charged particles 28 may be unevenly distributed in the space 41. In this case, the intensity of the microwave derived from the extraction position in the vicinity of the region where the charged particles 28 are gathered may be relatively weak. By making the intensity of the microwave introduced from the introduction position near the derivation position relatively strong, it becomes easy to irradiate the region where the charged particles 28 are gathered with the microwave. Therefore, the charged particles 28 can be burned efficiently.

In the example of FIG. 8, the microwave generation unit 130 and the intensity detection unit 140 are connected to different openings 48. In another example, the microwave generation unit 130 and the intensity detection unit 140 may be connected to a common opening 48. In this case, since the introduction position and the derivation position of the microwave are the same, it becomes easy to control the intensity of the introduced microwave according to the distribution of the charged particles 28.

Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various changes or improvements can be made to the above embodiments. It is clear from the claims that the form with such modifications or improvements may also be included in the technical scope of the invention.

28 ... charged particles, 30 ... first electrode, 32 ... partition wall, 34 ... reflective part, 36 ... charged particle accumulating part, 38 ... opening, 39 ... outer wall, 41 ... space, 42 ... opening, 44 ... gas flow path, 46 ... opening, 48 ... opening, 100 ... dust collector, 110 ... charging part, 120 ... Dust collector, 130 ... Microwave generator, 131 ... Waveguide, 140 ... Strength detection unit, 142 ... Derivation unit, 144 ... Microwave absorber, 146 ... Temperature detection Unit, 147 ... Rising waveform, 150 ... Control unit, 152 ... Calculation unit, 160 ... Flame detection unit, 200 ... Exhaust gas source

Claims

A dust collector that collects particles,
A microwave generating unit that generates microwaves to be introduced into the dust collecting unit and burns the particles collected in the dust collecting unit by the microwaves.
It is provided with an intensity detection unit that detects the intensity of the microwave that was not absorbed by the particles.
The microwave generating unit is a dust collector that controls the intensity of the microwave introduced into the dust collecting unit based on the intensity of the microwave detected by the intensity detecting unit.
The strength detector
A derivation unit that derives at least a part of the microwaves that were not absorbed by the particles from the dust collecting unit, and a derivation unit.
A microwave absorber that absorbs the microwave derived from the dust collector, and
The dust collector according to claim 1, further comprising a temperature detection unit that detects the temperature of the microwave absorber.
When the temperature of the microwave absorber becomes equal to or higher than the first reference temperature in a state where the microwave of the first intensity is introduced into the dust collecting portion, the microwave generating portion is connected to the dust collecting portion. The dust collector according to claim 2, wherein the intensity of the microwave to be introduced is switched to a second intensity lower than the first intensity.
The microwave generating unit is the dust collecting unit when the temperature of the microwave absorber becomes equal to or lower than the second reference temperature in a state where the microwave of the second intensity is introduced into the dust collecting unit. The dust collector according to claim 3, wherein the intensity of the microwave introduced in the above is switched to the first intensity.
Calculation to calculate the amount of combustibles of the particles accumulated in the dust collecting portion based on the integrated time in which the microwave generating portion introduces the microwave of the first intensity into the dust collecting portion. The dust collector according to claim 3, further comprising a unit.
Any one of claims 2 to 4, further comprising a calculation unit that calculates the amount of the particles introduced into the dust collector based on the slope of the rising waveform in the time waveform of the temperature detected by the temperature detection unit. The dust collector described in the section.
The lead-out unit is provided at a plurality of lead-out positions of the dust collector, and the lead-out unit is provided.
The dust collector according to any one of claims 2 to 6, wherein the microwave absorber absorbs the microwave in which the microwaves derived by the plurality of derivation units are combined.
The lead-out unit is provided at a plurality of lead-out positions of the dust collector, and the lead-out unit is provided.
The microwave generating unit introduces the microwave into the dust collecting unit from a plurality of introduction positions of the dust collecting unit.
The microwave absorber is provided at each of the lead-out positions.
Any one of claims 2 to 6, wherein the microwave generating unit controls the intensity of the microwave introduced from the corresponding introduction position based on the temperature of the microwave absorber at each of the derivation positions. The dust collector described in.
The intensity detecting unit determines in advance the relationship between the temperature of the microwave absorber and the intensity of the microwave when the microwave is introduced into the dust collecting unit in a state where the particles are not present in the dust collecting unit. The intensity of the microwave that was not absorbed by the particles is calculated from the temperature of the microwave absorber when the microwave is introduced into the dust collector in a state where the particles are present in the dust collector. The dust collector according to any one of claims 2 to 8 to be detected.
The intensity of the microwave absorbed by the particles is calculated from the difference between the intensity of the microwave detected by the intensity detecting unit and the intensity of the microwave introduced by the microwave generating unit into the dust collecting unit. The dust collector according to any one of claims 2 to 8, further comprising a calculation unit.
The collection according to claim 10, wherein the calculation unit calculates the amount of combustibles of the particles remaining in the dust collection unit based on the time integral value of the intensity of the microwave absorbed by the particles. Dust device.
A flame detection unit for detecting the occurrence of a flame in the dust collecting unit is further provided.
The microwave generating unit reduces the intensity of the microwave introduced into the dust collecting unit or stops the introduction of the microwave into the dust collecting unit when the flame is generated. The dust collector according to any one of 1 to 11.
Exhaust gas discharged from the exhaust gas source is introduced into the dust collector, and the exhaust gas is introduced.
The dust collecting device according to claim 12, wherein the microwave generating unit controls the intensity of the microwave introduced into the dust collecting unit based on the operating state of the exhaust gas source when the flame is generated.