Particle-aggregation-promoting device and dust collector

Abstract

This particle-aggregation-promoting device (3) comprises: a vibrating element (10); a plurality of flat plates (12) arranged in parallel with each other; a single screw shaft (11) linking the vibrator (10) and the flat plates (12) between the vibrating element (10) and the flat plates (12); and nuts (13) for linking the flat plates (12) to the screw shaft (11) at discretionary positions on the screw shaft (11).

Description

Particle aggregation promoter and dust collector

[0001] The present invention relates to a particle coagulation promotion device that promotes the coagulation of solid particles contained in air to be treated, and a dust collector equipped with the particle coagulation promotion device.

[0002] It is known to provide a particle aggregation promoting device inside a filter-type dust collector that filters the air to be treated to remove solid particles contained in the air to be treated. Equipping a dust collector with a particle aggregation promoting device increases the particle size of the solid particles, thereby improving the capture rate of the solid particles in the filter. It also makes it possible to capture solid particles with a coarse-mesh filter. Making the filter coarser reduces the flow resistance of the dust collector, thereby reducing the power required for the blower that supplies the air to be treated to the dust collector.

[0003] For example, the particle separator described in Patent Document 1 includes a reflector fixed to a flow path, a vibrating plate disposed within the flow path facing the reflector, and a vibrator that applies ultrasonic vibrations to the vibrating plate. According to the description in Patent Document 1, by vibrating the vibrating plate, standing waves are generated in the air to be treated between the vibrating plate and the reflector. The standing waves act on solid particles contained in the air to be treated, promoting the aggregation of the solid particles. As a result, the solid particles with enlarged particle sizes are captured and removed by a filter located at the downstream end of the flow path.

[0004] In this way, in the particle separator described in Patent Document 1, the set of the vibrator, the vibrating plate, and the reflecting plate functions as a particle aggregation promoting device.

[0005] Japanese Patent Application Laid-Open No. 2018-134612

[0006] Dust collectors are required to have an increased processing capacity per unit time. In order to increase the processing capacity per unit time, it is necessary to increase the flow rate of the air to be treated that passes through the dust collector per unit time. In order to increase the flow rate of the air to be treated that passes through the dust collector per unit time, it is necessary to increase the flow velocity of the air to be treated that passes through the dust collector or to increase the cross-sectional area of ​​the flow path of the dust collector.

[0007] However, increasing the flow velocity of the air to be treated passing through the dust collector increases the flow resistance, which increases the power required for blowing the air. Also, the noise generated by the dust collector increases. Therefore, it is not desirable to increase the flow velocity of the air to be treated passing through the dust collector.

[0008] On the other hand, if the cross-sectional area of ​​the flow path of the dust collector is increased, the above problem does not occur. However, in the dust collector described in Patent Document 1, increasing the cross-sectional area of ​​the flow path increases the gap between the vibrating plate and the reflecting plate. Increasing the gap between the vibrating plate and the reflecting plate causes the sound waves emitted from the vibrating plate to attenuate before reaching the reflecting plate, making it impossible to form a sufficient sound field. Therefore, solid particles contained in the air to be treated cannot be sufficiently coagulated. As a result, solid particles cannot be sufficiently captured and removed. Thus, the dust collector described in Patent Document 1 has the problem that simply increasing the cross-sectional area of ​​the flow path does not improve the processing capacity of the dust collector.

[0009] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a particle aggregation promotion device that functions sufficiently even when placed inside a dust collector having a large cross-sectional area of ​​the flow path, and to provide a dust collector equipped with the particle aggregation promotion device.

[0010] In order to achieve the above-mentioned object, the particle aggregation promotion device of the present invention comprises a vibrator, a plurality of flat plates arranged parallel to each other, a single rod-shaped member located between the vibrator and the flat plates and connecting them, and connecting means for connecting the flat plates to the rod-shaped member at any position on the rod-shaped member.

[0011] The rod-shaped member may be a threaded shaft having a male thread formed thereon, and the connecting means may be two nuts that are threaded onto the threaded shaft and clamp the flat plate therebetween.

[0012] The particle aggregation promotion device according to the present invention may include a collar that is inserted onto the screw shaft and is sandwiched between the flat plate and the nut, and the flat plate may be sandwiched between the two collars.

[0013] A dust collector according to the present invention comprises a housing, any one of the particle coagulation promotion devices described above disposed inside the housing, an inlet at one end of the housing through which air to be treated flows in, an outlet at the other end of the housing through which the air to be treated flows out, and a filter disposed at the outlet for capturing solid particles contained in the air to be treated. The flat plate of the particle coagulation promotion device is disposed parallel to the flow of the air to be treated from the inlet toward the outlet.

[0014] The particle aggregation promotion device according to the present invention includes a plurality of flat plates. The flat plates can function as vibrating plates that emit ultrasonic waves. Alternatively, some of the flat plates can function as reflecting plates that reflect ultrasonic waves emitted from other flat plates. Therefore, by appropriately adjusting the spacing between the flat plates, standing waves of ultrasonic waves can be generated in the spaces between the flat plates. By applying standing waves of ultrasonic waves to solid particles contained in the air to be treated, aggregation of the solid particles can be promoted.

[0015] The particle aggregation promotion device according to the present invention includes multiple flat plates, and therefore can generate ultrasonic standing waves of sufficient strength even when placed inside a dust collector with a large cross-sectional area of ​​the flow path, thereby enabling solid particles contained in the air to be treated to be sufficiently condensed inside the dust collector with a large cross-sectional area of ​​the flow path.

[0016] 1 is a side cross-sectional view showing the overall configuration of a dust collector according to an embodiment of the present invention. FIG. 2 is an explanatory diagram showing a detailed configuration of a connecting portion between a screw shaft and a flat plate shown in FIG. 1. FIG. 2A is a plan view of the collar shown in FIG. 2A, that is, a view of the collar as seen from the direction of arrow A shown in FIG. 2A. FIG. 2B is a cross-sectional view of the collar cut along the plane shown by line BB' in FIG. 2B. FIG. 2C is an explanatory diagram showing the operation of the dust collector shown in FIG. 1. FIG. 3 is a graph showing the relationship between the particle size of fine particles and the ratio of the amplitude of the fine particles vibrating when placed in an ultrasonic sound field to the amplitude of the ultrasonic waves. FIG. 4 is a perspective view showing the results of estimating the natural frequency of a flat plate, showing the vibration mode of the flat plate. FIG. 5 is a plan view showing the dimensions and shape of the collar. FIG. 6 is a side view showing the dimensions and shape of the collar. FIG. 7 is a side view showing the configuration of another example of connecting means for connecting a flat plate to a round bar. FIG. 8 is a plan view showing yet another example of connecting means.

[0017] The configurations and operations of a particle aggregation promotion device and a dust collector according to embodiments of the present invention will be described in detail below with reference to the drawings. Note that the same reference numerals are used in each drawing to designate the same or equivalent parts.

[0018] (Overall Configuration) FIG. 1 is a side cross-sectional view showing the configuration of a dust collector 1 according to an embodiment of the present invention.

[0019] As shown in FIG. 1, the dust collector 1 includes a housing 2 and a particle aggregation promoting device 3 .

[0020] 1, the housing 2 has an inlet 5 through which the air to be treated 4 flows in before treatment. A blower and a duct (not shown) are arranged upstream of the inlet 5. The air to be treated 4 generated in a location (not shown) is sucked in by the blower, flows through the duct, passes through the inlet 5, and flows into the housing 2.

[0021] 1, the housing 2 is provided with an outlet 7 through which the treated air 6 flows out. A filter 8 is attached to the outlet 7. The filter 8 is a filtering material that captures solid particles contained in the air to be treated 4. Therefore, the solid particles contained in the air to be treated 4 are removed when the air passes through the filter 8.

[0022] 1, a reflector 9a is fixed to the top surface of the housing 2, and a reflector 9b is fixed to the surface of the housing 2. The functions of the reflectors 9a and 9b will be described later.

[0023] (Particle Aggregation Promotion Device) Next, the configuration of the particle aggregation promotion device 3 will be described. The particle aggregation promotion device 3 is a device that promotes aggregation of fine solid particles contained in the air to be treated that passes through the housing 2. As shown in Fig. 1, the particle aggregation promotion device 3 includes a vibrator 10 arranged outside the housing 2, a screw shaft 11 connected to the output end of the vibrator 10 and extending into the housing 2, and three flat plates 12 arranged inside the housing 2 and connected to the screw shaft 11.

[0024] A piezoelectric element such as PZT (lead zirconate titanate) is built into the vibrator 10. The vibrator 10 can generate ultrasonic vibrations by applying a pulse voltage supplied from a power supply (not shown) to the piezoelectric element.

[0025] The screw shaft 11 is an example of a rod-shaped member in the present invention, and is a member that receives vibration from the vibrator 10 and vibrates in the vertical direction, i.e., in the longitudinal direction of the screw shaft 11. A male thread is formed over the entire length of the screw shaft 11. The screw shaft 11 is located between the vibrator 10 and the flat plate 12 and corresponds to a member that connects the two.

[0026] The flat plate 12 is a metal plate, and functions as a vibration plate or a reflector depending on its mounting position on the screw shaft 11. That is, when the flat plate 12 is connected to a portion corresponding to an antinode of the vibration of the screw shaft 11, which vibrates in response to the vibration of the vibrator 10, the flat plate 12 resonates with the vibrator 10 and radiates ultrasonic waves to the surroundings. That is, in this case, the flat plate 12 functions as a vibration plate. When the flat plate 12 is connected to a portion corresponding to a node of the vibration of the screw shaft 11, vibration is not transmitted to the flat plate 12. In this case, the flat plate 12 functions as a reflector that reflects ultrasonic waves radiated by other flat plates 12 that function as vibration plates.

[0027] The material, dimensions, and shape of the flat plate 12 are selected so that it resonates with the vibration of the vibrator 10 and vibrates flexurally. In other words, the flat plate 12 is designed to have the same natural frequency as the vibration frequency of the vibrator 10. Specific design examples of the flat plate 12 will be described later.

[0028] 1 , the three flat plates 12 are arranged parallel to each other and facing each other. The three flat plates 12 are also arranged parallel to the flow of the air 4 to be treated from the inlet 5 toward the outlet 7. That is, inside the housing 2 of the dust collector 1, the air 4 to be treated flows parallel to the three flat plates 12.

[0029] As shown in FIG. 1 , a total of 12 nuts 13 are threaded onto the screw shaft 11. The nuts 13 are threaded onto the screw shaft 11 in pairs, forming a so-called double nut. A pair of nuts 13 is arranged above and below each flat plate 12. That is, each flat plate 12 is sandwiched between two pairs of double nuts. A collar 14 is inserted into the screw shaft 11, and the collar 14 is sandwiched between the flat plate 12 and the nuts 13. In this way, the flat plate 12 is connected to the screw shaft 11 by the nuts 13 and collar 14. The specific functions of the nuts 13 and collar 14 will be described later.

[0030] Next, the detailed configuration of the connecting portion between the screw shaft 11 and the flat plate 12 will be described with reference to Figures 2A, 2B, and 2C. Figure 2A is an enlarged view showing the connecting portion between the screw shaft 11 and the flat plate 12, and Figure 2B is a view of the collar 14 as seen from the direction of arrow A shown in Figure 2A, i.e., a plan view of the collar 14. Figure 2C is a cross-sectional view of the collar 14 taken along the plane indicated by line BB' in Figure 2B.

[0031] As shown in Figure 2A, two nuts 13 are arranged at the top of the connection between the screw shaft 11 and the flat plate 12, with a collar 14 arranged below that and the flat plate 12 arranged below that. Another collar 14 is arranged below the flat plate 12, with two more nuts 13 arranged below that. In other words, a set of a collar 14 and two nuts 13 is arranged above and below the flat plate 12. The collar 14 is sandwiched between the nuts 13 and the flat plate 12. The four nuts 13 are threaded onto the screw shaft 11. The screw shaft 11 is inserted through the collar 14 and the flat plate 12.

[0032] Because of the above configuration, by rotating the nuts 13 relative to the screw shaft 11, the nuts 13 can be moved up and down relative to the screw shaft 11. Therefore, by moving all four nuts 13 in the same direction relative to the screw shaft 11, the flat plate 12 can be moved up and down relative to the screw shaft 11. For example, in FIG. 2A , by moving all four nuts 13 upward in order starting from the top nut 13, the flat plate 12 can be moved upward relative to the screw shaft 11. Conversely, by moving all four nuts 13 downward in order starting from the bottom nut 13, the flat plate 12 can be moved downward relative to the screw shaft 11. Then, by rotating the two nuts 13 arranged above the flat plate 12 so that these two nuts 13 move downward, and by rotating the two nuts 13 arranged below the flat plate 12 so that these two nuts 13 move upward, the flat plate 12 is fixed to the screw shaft 11.

[0033] In this way, the nut 13 and the collar 14 function as a connecting means for connecting the flat plate 12 to the screw shaft 11. Furthermore, the nut 13 and the collar 14 allow the flat plate 12 to be connected to the screw shaft 11 at any position on the screw shaft 11.

[0034] 2A, the outer diameter of the collar 14 is smaller than the outer diameter of the nut 13. As shown in Figures 2B and 2C, the outer diameter of the end of the collar 14 that abuts against the flat plate 12 is smaller than the outer diameter of the end that abuts against the nut 13. Therefore, the range over which the displacement of the flat plate 12 is constrained by the abutment of the collar 14 is smaller than the range over which the displacement of the flat plate 12 is constrained by the nut 13 directly abutting against the flat plate 12.

[0035] (Function of Dust Collector) Fig. 3 is an explanatory diagram showing the function of the dust collector 1. As described above, in the particle aggregation promotion device 3, the connection position of the flat plate 12 with respect to the screw shaft 11 can be changed individually and arbitrarily. In addition, by changing the frequency of the pulse voltage applied to the vibrator 10, the vibration frequency of the vibrator 10 can be changed.

[0036] In the dust collector 1, by appropriately adjusting the connection position of the flat plate 12 relative to the screw shaft 11 and the vibration frequency of the vibrator 10, ultrasonic standing waves can be generated in the spaces A1 to A4 shown in FIG.

[0037] For example, if all three flat plates 12 are connected to locations corresponding to the antinodes of vibration of the screw shaft 11, all three flat plates 12 function as vibration plates, and ultrasonic waves are emitted from all three flat plates 12. As a result, ultrasonic standing waves are generated in the spaces A2 and A3. If two of the three flat plates 12, located at the top and bottom ends, are connected to locations corresponding to the antinodes of vibration of the screw shaft 11, these two flat plates 12 function as vibration plates. If the remaining plate 12 is connected to a location corresponding to the node of vibration of the screw shaft 11, this one flat plate 12 functions as a reflector. In this case as well, ultrasonic standing waves are generated in the spaces A2 and A3.

[0038] If the wavelength of the ultrasonic waves emitted from the flat plate 12 functioning as a vibration plate is λ and N is an arbitrary integer, then by adjusting the position of the flat plate 12 so that the spacing S1 between the flat plate 12 at the upper end and the reflector 9a in Fig. 3 is 0.5 × λ × N, i.e., so that S1 is a multiple of half the wavelength, a standing wave of ultrasonic waves will be generated in the space A1. If the position of the flat plate 12 is adjusted so that the spacing S4 between the flat plate 12 at the lower end and the reflector 9b in Fig. 3 is 0.5 × λ × N, i.e., so that S4 is a multiple of half the wavelength, a standing wave of ultrasonic waves will be generated in the space A4.

[0039] In this way, ultrasonic standing waves can be generated in all of the spaces A1 to A4 in the dust collector 1. Furthermore, since the dust collector 1 includes three flat plates, standing waves of sufficient strength can be generated in all parts of the flow path of the dust collector 1. Therefore, aggregation of solid particles contained in the air to be treated can be promoted in all parts of the flow path of the dust collector 1.

[0040] (Design Examples of Flat Plate and Function of Collar) Here, design examples of the flat plate 12 and the function of the collar 14 will be described.

[0041] Generally, the particle collection efficiency of the filter 8 is nearly 100% when the particle size is 5 μm or greater, but gradually decreases as the particle size decreases. It is known that the capture rate is approximately 80% when the particle size is approximately 2 μm, and less than 20% when the particle size is approximately 0.5 μm or less (e.g., Hakamata T., Ushiroebisu K., et al., Performance of pulse-jet type bag filter, 6th World Filtration Congress, (1993) 483). Therefore, the particle aggregation promotion device 3 included in the filtration-type dust collector 1 must apply ultrasonic waves to particles less than 2.0 μm in size to reduce the particle size of all particles to 5 μm or greater. To achieve this, the particle aggregation promotion device 3 must vibrate the particles at various amplitudes. If all particles vibrate at the same frequency and amplitude, the relative velocity between particles becomes zero, preventing collisions between particles.

[0042] It is known that the amplitude (Xp) of a particle placed in an ultrasonic field varies depending on the particle size and the ultrasonic frequency (e.g., Brandt, O., Freund, H. and Hiedemann, E., Kolloid Z. 77, 103 (1936)). As the particle size decreases, the amplitude (Xp) of the particle approaches the amplitude (Xg) of the ultrasonic wave. In other words, as the particle size decreases, the ratio (Xp / Xg) of the particle amplitude (Xp) to the ultrasonic amplitude (Xg) approaches 1. Furthermore, the value of Xp / Xg never exceeds 1. Therefore, when the particle size becomes sufficiently small, the amplitude (Xp) of the particle becomes equal to the amplitude (Xg) of the ultrasonic wave, and even if the particle size is further reduced, the amplitude (Xp) of the particle does not change.

[0043] On the other hand, when the particle size of the microparticles is increased, the amplitude (Xp) of the microparticles decreases. In other words, when the particle size of the microparticles is increased, the ratio (Xp / Xg) of the amplitude (Xp) of the microparticles to the amplitude (Xg) of the ultrasonic waves approaches 0. Therefore, when the particle size of the microparticles is sufficiently large, the amplitude (Xp) of the microparticles becomes almost 0, and even if the particle size of the microparticles is further reduced, the amplitude (Xp) of the microparticles does not change.

[0044] Thus, the amplitude (Xp) of a particle placed in an ultrasonic field changes depending on the particle size when the particle size is within a certain range. It is known that the particle size range varies depending on the ultrasonic frequency. Figure 4 is a graph showing the relationship between particle size and Xp / Xg, and is a graph published in the aforementioned paper by Brandt et al. In Figure 4, the horizontal axis represents the radius of particles (particle size), and the vertical axis represents the fraction of particle vibrating with gas amplitude, which corresponds to the above Xp / Xg. The graph also shows curves showing the relationship between the particle size of a particle placed in an ultrasonic field at a constant frequency and the value of Xp / Xg generated for that particle when the ultrasonic frequency is set to 1, 5, 10, 20, 50, or 100 kHz.

[0045] 4, it can be seen that the slope of the curve becomes steeper when Xp / Xg is between 0.8 and 0.2, regardless of the ultrasonic frequency. In other words, when the particle size of the microparticles is in the range where Xp / Xg is between 0.8 and 0.2, the difference in amplitude between microparticles of different sizes becomes large. It can also be seen that as the ultrasonic frequency increases, the range of particle size where Xp / Xg is between 0.8 and 0.2 shifts to the left of the graph.

[0046] 4, when the ultrasonic frequency is set to 20 kHz, Xp / Xg is approximately 0.8 when the particle diameter is approximately 0.7 μm, and Xp / Xg is approximately 0.2 when the particle diameter is approximately 2.0 μm. In other words, it can be seen that the amplitude of the particle changes significantly as the particle diameter changes between approximately 0.7 μm and 2.0 μm. Therefore, when the particles to be processed are placed in an ultrasonic sound field with a frequency of 20 kHz, collisions and aggregation of particles between approximately 0.7 μm and 2.0 μm are promoted. As a result, a large number of particles exceeding 5.0 μm in diameter are generated early in the processing. Particles less than 0.7 μm in diameter collide with particles exceeding 5.0 μm in diameter and aggregate due to their reduced amplitude. Thus, by setting the ultrasonic frequency to 20 kHz, it is possible to aggregate particles of all particle sizes in a short time, and all particles can be made larger than 5.0 μm in diameter.

[0047] When the ultrasonic frequency is set to 1, 5, or 10 kHz, collisions and aggregation of particles originally exceeding 2.0 μm are promoted, resulting in larger particle sizes for the particles ultimately generated. However, aggregation of particles less than 0.7 μm is delayed, resulting in longer overall processing time. When the ultrasonic frequency is set to 50 kHz or 100 kHz, the amplitude change becomes smaller when the particle size exceeds 2.0 μm, making it difficult to generate particles exceeding 5.0 μm. This results in longer overall processing time. Thus, in order to efficiently generate particles exceeding 5.0 μm in particle size in the particle aggregation promotion device 3, an ultrasonic frequency of 20 kHz is optimal.

[0048] Therefore, when designing the particle aggregation promotion device 3, if the flat plate 12 is to function as a vibrating plate, it is necessary to design the flat plate 12 so that it resonates at 20 kHz and vibrates flexurally in a stripe mode.

[0049] Therefore, in this embodiment, a duralumin A2017 plate having a thickness of 3 mm, a length of 443 mm, and a width of 170 mm was used as the flat plate 12. FIG. 5 is a perspective view showing the vibration mode of the flat plate 12, illustrating the results of estimating the natural frequency when the flat plate 12 is point-supported at its center. It was found that the flat plate 12 has a natural frequency near 20 kHz and flexurally vibrates in the mode shown in FIG. 5. In the mode shown in FIG. 5, the internodal length is approximately 17 mm. In this way, if the flat plate 12 can be connected to the screw shaft 11 in a state close to point support, it can resonate at 20 kHz and flexurally vibrate in the stripe mode.

[0050] Therefore, in this embodiment, the dimensions and shape of the collar 14 were selected as shown in Figures 6A and 6B. That is, the outer diameter of the top surface of the collar 14, i.e., the surface that contacts the flat plate 12, is 14.2 mm. This selection of dimensions allows the collar 14 to abut against the flat plate 12 within the range of the internodal length of the vibration mode shown in Figure 5. Therefore, the range of the flat plate 12 that is restrained by the collar 14 can be limited to the range of the internodal length, so the flat plate 12 is supported by the screw shaft 11 in a state close to point support. As a result, the flat plate 12 vibrates in a mode close to the mode shown in Figure 5. On the other hand, if the collar 14 were not provided and the nut 13 were abutted against the flat plate 12, the flat plate 12 would be restrained beyond the range of the internodal length, and the vibration mode shown in Figure 5 would not be obtained.

[0051] If the flat plate 12 is to function as a reflector, the collar 14 is not necessary. Alternatively, the collar 14 and the nut 13 may be integrally formed, and the collar 14 may be omitted. In other words, the end surface of the nut 13 that comes into contact with the flat plate 12 may be machined to form a portion that functions as the collar 14.

[0052] (Modifications of the Coupling Means) In the above, the threaded shaft 11 was shown as a specific example of a rod-shaped member. Furthermore, the nut 13 and collar 14 were shown as specific examples of the coupling means for coupling the flat plate 12 to the threaded shaft 11. However, the rod-shaped member is not limited to the threaded shaft 11. For example, as shown in FIG. 7A , a metal round bar 15 may be used as the rod-shaped member. Instead of the nut 13, a metal ring 16 may be inserted into the round bar 15 and fixed to the round bar 15 by shrink fitting. That is, as shown in FIG. 7A , the ring 16 and collar 14 may be used as the coupling means for coupling the flat plate 12 to the round bar 15. In this case, a trial run of the dust collector 1 is performed with the ring 16 temporarily fastened to the round bar 15 by some means. After adjusting the coupling position of the flat plate 12, the dust collector 1 is disassembled and the shrink fitting process is performed. After the shrink fitting process is completed, the dust collector 1 is reassembled.

[0053] Alternatively, instead of the ring 16, a C-shaped clamp 17 may be provided that is inserted onto the round bar 15, as shown in Fig. 7B. The C-shaped clamp 17 is literally a metal part that is C-shaped in plan view, with a bolt 18 threaded onto one end. By tightening the bolt 18, the C-shaped clamp 17 is fixed to the round bar 15. By loosening the bolt 18, the C-shaped clamp 17 becomes slidable relative to the round bar 15. Therefore, if the C-shaped clamp 17 and the collar 14 form a connecting means, it becomes easy to adjust the position of the flat plate 12.

[0054] As described above, the particle aggregation promotion device 3 includes a plurality of flat plates 12, and the flat plates 12 can function as vibration plates that emit ultrasonic waves or as reflection plates that reflect ultrasonic waves emitted from the vibration plates. By adjusting the distance between the flat plates 12, standing waves of ultrasonic waves can be generated in the space between one flat plate 12 and another flat plate 12 facing it.

[0055] If the dust collector 1 is provided with the particle aggregation promotion device 3, aggregation of fine solid particles contained in the air to be treated is promoted within the flow path of the dust collector 1. As a result, the particle diameter of the solid particles increases, making it easier for the filter 8 to capture the solid particles. Furthermore, since the particle aggregation promotion device 3 includes multiple flat plates 12, the mutual spacing between the flat plates 12 can be maintained appropriately even if the flow path of the dust collector 1 is enlarged. Therefore, even if the flow path of the dust collector 1 is enlarged, it is possible to generate ultrasonic standing waves of the strength required to promote aggregation of solid particles. Therefore, if the dust collector 1 is provided with the particle aggregation promotion device 3, it becomes easier to enlarge the dust collector 1.

[0056] However, the technical scope of the present invention is not limited by the specific configurations of the above-mentioned dust collector 1 and particle aggregation promotion device 3. The present invention can be freely applied, modified, or improved within the scope of the technical concept set forth in the claims.

[0057] For example, although the above example shows that the particle aggregation promotion device 3 includes three flat plates 12, the particle aggregation promotion device according to the present invention is not limited to one including three flat plates. The particle aggregation promotion device according to the present invention may include four or five or more flat plates.

[0058] In the above example, the dust collector 1 is provided with the reflecting plates 9a and 9b, but the reflecting plates 9a and 9b are not essential components of the dust collector according to the present invention. Alternatively, the top plate or the bottom plate of the housing 2 may be configured to function as the reflecting plates 9a and 9b.

[0059] Although the example in which the vibrator 10 is disposed outside the housing 2 has been described above, the vibrator 10 may be disposed inside the housing 2. In other words, the entire particle aggregation promotion device 3 including the vibrator 10 may be disposed inside the housing 2.

[0060] In the above, two nuts 13 are arranged above and below the flat plate 12 to form a so-called double nut. However, in the present invention, when nuts are provided in the connecting means, the nuts do not have to form a double nut.

[0061] Furthermore, although the above describes an example of vibrator 10 that generates ultrasonic vibrations by applying a pulse voltage to a piezoelectric element, the configuration and operating principle of the vibrator provided in the particle aggregation promotion device according to the present invention are not limited to this. It is sufficient for the vibrator provided in the particle aggregation promotion device according to the present invention to have the function of generating ultrasonic vibrations, and the configuration, type, or operating principle of the vibrator can be selected arbitrarily.

[0062] The present invention allows various embodiments and modifications without departing from the broad spirit and scope of the present invention. Furthermore, the above-described embodiments are intended to explain the present invention and do not limit the scope of the present invention. That is, the scope of the present invention is defined by the claims, not the embodiments. Various modifications made within the scope of the claims and the meaning of the disclosure equivalent thereto are considered to be within the scope of the present invention.

[0063] This application is based on Japanese Patent Application No. 2023-195398, filed on November 16, 2023. The entire specification, claims, and drawings of Japanese Patent Application No. 2023-195398 are incorporated herein by reference.

[0064] The particle aggregation promoting device according to the present invention is useful in the industrial or consumer fields as a device for promoting aggregation of fine solid particles contained in air to be treated. The dust collector according to the present invention is useful in the industrial or consumer fields as a dust collector for removing fine particles contained in air to be treated.

[0065] 1 Dust collector, 2 Housing, 3 Particle aggregation promotion device, 4 Air to be treated, 5 Inlet, 6 Treated air, 7 Outlet, 8 Filter, 9a, 9b Reflector, 10 Vibrator, 11 Screw shaft, 12 Vibration plate, 13 Nut, 14 Collar, 15 Round bar, 16 Ring, 17 C-shaped clamp, 18 Bolt,

Claims

1. A particle aggregation promotion device comprising: a vibrator; a plurality of flat plates arranged parallel to each other; a single rod-shaped member located between the vibrator and the flat plates and connecting the two; and connecting means for connecting the flat plates to the rod-shaped member at any position on the rod-shaped member.

2. The particle aggregation promotion device according to claim 1, wherein the rod-shaped member is a threaded shaft having a male thread, and the connecting means is two nuts that are screwed onto the threaded shaft and clamp the flat plate.

3. The particle aggregation promotion device according to claim 2, further comprising a collar that is inserted onto the screw shaft and sandwiched between the flat plate and the nut, and the flat plate is sandwiched between two of the collars.

4. A dust collector comprising: a housing; and a particle agglomeration promotion device according to any one of claims 1 to 3 arranged inside the housing; and further comprising an inlet at one end of the housing through which air to be treated flows in and an outlet at the other end of the housing through which the air to be treated flows out; and a filter arranged at the outlet for capturing solid particles contained in the air to be treated, wherein the flat plate of the particle agglomeration promotion device is arranged parallel to the flow of the air to be treated from the inlet toward the outlet.

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