Electrostatic precipitator and stacking forming device

Abstract

An electrostatic precipitator and a stacking forming device are provided to prevent clogging of an ozone removal filter and prolong the life of the ozone removal filter. An electrostatic precipitator is provided, comprising: a gas inlet for supplying gas containing dust as a magnetic body; a charging section for charging the dust; a dust collecting section for collecting the charged dust; a cleaning device including at least one of a charging section cleaning device and a dust collecting section cleaning device; a magnetic filter disposed on the downstream side of the dust collecting section; an ozone removal filter disposed on the downstream side of the magnetic filter for removing ozone from the gas; and a gas outlet for discharging the gas from which dust and ozone have been removed, wherein the magnetic filter has a structure configured in the following manner, namely, a plurality of magnet plates are arranged at a predetermined interval, and in each magnet plate disposed on the upper side of the center, the downstream side of each magnet plate is inclined downward, and in each magnet plate disposed on the lower side of the center, the downstream side of each magnet plate is inclined upward.

Description

Technical Field

[0001] The invention relates to an electric precipitator and a stacking forming device comprising the electric precipitator. Background Art

[0002] As a device for removing dust from gas, an electric precipitator is known. The electric precipitator includes a charging unit that positively or negatively charges dust contained in the gas by corona discharge, and a dust collecting unit that collects the charged dust by Coulomb force.

[0003] This type of electric precipitator is effectively used, for example, in the field of stacking molding. In a stacking molding device, in order to prevent the deterioration of the material layer and the solidified layer, the solidified layer is formed in a chamber filled with an inert gas. Moreover, in the stacking molding device, when the material layer is irradiated with laser light or electron beam to melt or sinter it to form a solidified layer, smoke called fume is generated as a kind of dust. This fume may block the laser light or electron beam, or contaminate optical parts, and thus may affect the molding quality. Therefore, the stacking molding device is constructed so that an inert gas of a specified concentration is supplied to the chamber, and the inert gas containing fume is discharged from the chamber. The inert gas discharged from the chamber is sent to the electric precipitator, and the fume is removed from the inert gas and then returned to the chamber. In this way, the chamber is kept in a clean inert gas environment, and the inert gas is reused.

[0004] If an electric dust collector is used for a long time, dust will accumulate in the charged part or the dust collecting part, resulting in a decrease in the collection capacity. Therefore, there is a known electric dust collector that cleans the charged part or the dust collecting part during use, thereby extending the continuous use time. For example, Patent Document 1 discloses an electric dust collector that cleans the charged part by spraying an inactive gas, and cleans the dust collecting part using a scraper or the like.

[0005] Moreover, in the electric dust collector, ozone may be generated during corona discharge. Ozone emits a unique odor, and therefore, from the perspective of industrial hygiene, it is not desirable to release it directly to the outside. Moreover, ozone may deteriorate components including resin or rubber, etc. Therefore, it is desirable to remove ozone generated by corona discharge from the gas. Patent document 2 discloses an electric dust collector including an ozone removal device for removing ozone generated by corona discharge.

[0006] In addition, in the electric dust collector, in addition to the dust collecting part, a member configured to collect dust is sometimes provided. For example, Patent Document 3 discloses an electric dust collector including a magnetic dust collecting plate including an electromagnet near a gas inlet and a gas outlet. If the dust is a magnetic body, it can be captured by such a magnetic dust collecting plate.

[0007] [Prior art literature]

[0008] [Patent Document]

[0009] [Patent Document 1] Japanese Patent No. 6095147

[0010] [Patent Document 2] Japanese Patent No. 6600211

[0011] [Patent Document 3] Japanese Patent Utility Model Publication No. 54-037507 Summary of the invention

[0012] [Problems to be solved by the invention]

[0013] In an electric precipitator including a cleaning device for cleaning a charging part or a dust collecting part, secondary scattering occurs during cleaning, that is, dust attached to the charging part or the dust collecting part is blown up and scattered again into the gas. In particular, a dry electric precipitator that captures dust in a dry state and does not use a cleaning fluid during cleaning has a larger amount of secondary scattering of dust than a wet electric precipitator that sprays a cleaning fluid on the dust collecting part to wash away the dust.

[0014] Furthermore, in an electrostatic precipitator further including an ozone removing filter for removing ozone from gas, there is a possibility that the secondarily scattered dust adheres to the ozone removing filter and clogs the ozone removing filter.

[0015] Furthermore, in order to extend the life of the ozone removal filter, it is desirable that the gas flows substantially evenly over a wider area of ​​the ozone removal filter.

[0016] The present invention is completed in view of this situation, and its purpose is to provide an electrostatic precipitator and a stacking forming device to prevent secondary scattered dust from adhering to the ozone removal filter and causing clogging, and to allow gas to flow roughly evenly over a wider area of ​​the ozone removal filter, thereby extending the life of the ozone removal filter.

[0017] [Technical means to solve the problem]

[0018] According to the present invention, an electric dust collector is provided, comprising: a frame; a gas inlet, which is provided in the frame and supplies gas containing dust as a magnetic body; a charging part, which is provided in the frame and charges the dust positively or negatively; a dust collecting part, which is provided in the frame and captures the charged dust; a cleaning device, which is provided in the frame and includes at least one of a charging part cleaning device for removing dust attached to the charging part and a dust collecting part cleaning device for removing dust attached to the dust collecting part; a magnetic filter, which is provided in the frame on the downstream side of the dust collecting part; an ozone removal filter, which is provided in the frame on the downstream side of the magnetic filter and removes ozone from the gas; and a gas outlet, which is provided in the frame and discharges the gas from which the dust and ozone have been removed, wherein the magnetic filter has a structure arranged in the following manner, that is, a plurality of magnet plates are arranged at a predetermined interval, and in each magnet plate provided on the upper side than the center, the downstream side of each magnet plate is inclined downward, and in each magnet plate provided on the lower side than the center, the downstream side of each magnet plate is inclined upward.

[0019] [Effects of the Invention]

[0020] In the electric precipitator of the present invention, a magnetic filter is arranged on the downstream side of the dust collecting section, and an ozone removal filter is arranged on the downstream side of the magnetic filter. Moreover, the magnetic filter has a structure arranged in the following manner, that is, a plurality of magnet plates are arranged at a predetermined interval, and in each magnet plate arranged on the upper side than the center, the respective downstream side is inclined downward, and in each magnet plate arranged on the lower side than the center, the respective downstream side is inclined upward. When the dust is a magnetic body, according to this kind of magnetic filter, the secondary scattered dust can be adsorbed and removed, thereby preventing the ozone removal filter from being clogged. Moreover, the magnet plates arranged as described above play the role of a rectifier plate, so that the gas can be made to flow roughly evenly over a wider area in the filtering area of ​​the ozone removal filter, and the life of the ozone removal filter can be extended. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a side view of the stacking formation device of this embodiment.

[0022] Figure 2 yes Figure 1 II-II arrow diagram.

[0023] Figure 3 This is a three-dimensional view of the recoater head as seen from above.

[0024] Figure 4 This is a three-dimensional view of the recoater head as seen from below.

[0025] Figure 5 This is a schematic diagram of the structure of the irradiation device.

[0026] Figure 6It is a schematic structural diagram of the electric precipitator of this embodiment.

[0027] Figure 7 yes Figure 6 VII-VII arrow diagram.

[0028] Figure 8 yes Figure 6 VIII-VIII arrow diagram.

[0029] Fig. 9 It is a three-dimensional diagram of a magnetic filter.

[0030] Fig.10 It is a cross-sectional view of the magnet plate according to this embodiment.

[0031] Fig.11 It is a schematic structural diagram of an electric precipitator according to a modified example.

[0032] [Explanation of Symbols]

[0033] 1: Layered shaping device

[0034] 3: Material layer forming device

[0035] 4: Irradiation device

[0036] 5: Cutting device

[0037] 6: Electric dust collector

[0038] 7: Cleaning device

[0039] 8: Magnetic filter

[0040] 11: Chamber

[0041] 11a: Modeling Room

[0042] 11b: Drive room

[0043] 11c: Snake Belly

[0044] 13: Window

[0045] 15: Pollution prevention device

[0046] 17: Inert gas supply device

[0047] 19: Branch pipe

[0048] 21a~21e:Supply port

[0049] 22a~22c:Discharge outlet

[0050] 23a: Divider

[0051] 23b: Upper guide plate

[0052] 23c: Lower guide plate

[0053] 23d: Fan

[0054] 23e: Rectifier

[0055] 31: Base

[0056] 33: Recoat the machine head

[0057] 35, 731: scraper

[0058] 37: Shaping Platform

[0059] 39: Shaping platform drive device

[0060] 41: Light Source

[0061] 43: Collimator

[0062] 45: Focus control unit

[0063] 47: Scanning device

[0064] 51: Processing head

[0065] 53: Spindle

[0066] 55: X-axis drive device

[0067] 57: Y-axis drive device

[0068] 59: Z-axis drive device

[0069] 61: Frame

[0070] 62: Gas inlet

[0071] 63: Live part

[0072] 64: Dust collection unit

[0073] 65: Storage

[0074] 66: Ozone removal filter

[0075] 67: Oxygen concentration meter

[0076] 68: Fan

[0077] 69: Gas outlet

[0078] 71: Live parts cleaning device

[0079] 73: Dust collection cleaning device

[0080] 81: Magnetic board

[0081] 83: Framework

[0082] 91: Bottom plate

[0083] 93: Material layer

[0084] 95: Curing layer

[0085] 171: First inert gas supply device

[0086] 172: Second inert gas supply device

[0087] 331: Material Containment Department

[0088] 332: Material supply port

[0089] 333: Material discharge port

[0090] 471: X-axis galvanometer

[0091] 472: Y-axis galvanometer

[0092] 631: Charged Electrode

[0093] 632: Opposite electrodes

[0094] 641: Dust collecting plate

[0095] 642: Positive plate

[0096] 711: Nozzle

[0097] 712: Intermittent spray control unit

[0098] 811: Permanent magnet

[0099] 812: Shell

[0100] 831: Incision

[0101] L: Laser light DETAILED DESCRIPTION

[0102] The following is an explanation of the embodiments of the present invention using the accompanying drawings. In particular, the embodiments of the present invention are explained as a stacking forming device including an electric precipitator, the gas sent to the electric precipitator is an inert gas, and the dust to be captured is a magnetic mist generated when the solidified layer is formed. The various modifications described below can be implemented in any combination.

[0103] Figure 1 as well as Figure 22 shows a schematic structure of the stacking forming apparatus 1 of the present embodiment. The stacking forming apparatus 1 is an apparatus that alternately repeats the formation of a material layer 93 and the formation of a solidified layer 95, and stacks a plurality of solidified layers 95 to produce a desired three-dimensional object. The stacking forming apparatus 1 includes a chamber 11, a material layer forming apparatus 3, an irradiation apparatus 4, a cutting apparatus 5, and an inert gas supply and exhaust mechanism.

[0104] The chamber 11 is substantially sealed and covers the area where the desired three-dimensional object can be formed, i.e., the forming area. During the forming, the chamber 11 is filled with an inert gas of a predetermined concentration. The chamber 11 is divided by the bellows 11c into a forming chamber 11a having a forming area and forming the three-dimensional object, and a driving chamber 11b accommodating most of the driving device of the cutting device 5. Between the forming chamber 11a and the driving chamber 11b, there is a small gap, i.e., a connecting portion, through which only the inert gas can pass.

[0105] The material layer forming device 3 is arranged in the forming chamber 11a of the chamber 11, and forms a material layer 93 of a predetermined thickness. The material layer forming device 3 includes a base table 31 having a forming area and a recoating head 33 arranged on the base table 31. The recoating head 33 is configured to be movable in the horizontal direction by a recoating head driving device (not shown) having an arbitrary actuator. In the forming area, a forming platform 37 is arranged. The forming platform 37 is configured to be movable in the vertical direction by a forming platform driving device 39 having an arbitrary actuator. During forming, a base plate 91 may also be arranged on the forming platform 37, and a first layer of the material layer 93 may be formed on the base plate 91.

[0106] like Figure 3 as well as Figure 4 As shown, the recoater head 33 includes a material storage section 331, a material supply port 332, and a material discharge port 333. The material storage section 331 stores material powder. The material supply port 332 is provided on the upper surface of the material storage section 331, and serves as a receiving port for material powder supplied to the material storage section 331 from a material supply device (not shown). The material discharge port 333 is provided on the bottom surface of the material storage section 331, and discharges the material powder in the material storage section 331. The material discharge port 333 has a slit shape extending in a horizontal direction orthogonal to the moving direction of the recoater head 33. A scraper 35 is provided on the side of the recoater head 33 to flatten the material powder to form a material layer 93. The recoater head 33 generally discharges the material powder contained in the material storage section 331 from the material discharge port 333 while reciprocating in the horizontal direction on the forming area. At this time, the scraper 35 flattens the discharged material powder to form a material layer 93. In the present embodiment, the material powder may be any magnetic substance, and typically is a ferromagnetic metal powder.

[0107] The irradiation device 4 is provided above the chamber 11. The irradiation device 4 irradiates the laser light L to the predetermined irradiation area of ​​the material layer 93 formed on the forming area, so that the material layer 93 at the irradiation position is melted or sintered to form a solidified layer 95. The irradiation area exists in the forming area and is roughly consistent with the area surrounded by the contour shape of the three-dimensional forming object in the predetermined segmented layer. Figure 5 As shown, the irradiation device 4 includes a light source 41 , a collimator 43 , a focus control unit 45 and a scanning device 47 .

[0108] The light source 41 generates laser light L. Here, the type of laser light L is not limited as long as it can sinter or melt the material layer 93, and it can be, for example, fiber laser, CO2 laser, yttrium aluminum garnet (YAG) laser, green laser or blue laser. The collimator 43 converts the laser light L output from the light source 41 into parallel light. The focus control unit 45 has a focus adjustment lens and a lens actuator that moves the focus adjustment lens back and forth, and adjusts the laser light L output from the light source 41 to a desired spot diameter. The scanning device 47 is, for example, a galvanometer scanner. The scanning device 47 has an X-axis galvanometer mirror 471, an X-axis mirror actuator that rotates the X-axis galvanometer mirror 471, a Y-axis galvanometer mirror 472, and a Y-axis mirror actuator that rotates the Y-axis galvanometer mirror 472. The rotation angles of the X-axis galvanometer mirror 471 and the Y-axis galvanometer mirror 472 are controlled so that the laser light L output from the light source 41 performs two-dimensional scanning.

[0109] The laser light L that has passed through the X-axis galvanometer mirror 471 and the Y-axis galvanometer mirror 472 is transmitted through the window 13 provided on the upper surface of the chamber 11 and irradiated to the material layer 93 formed in the formation area. The window 13 is formed of a material that can transmit the laser light L. For example, when the laser light L is a fiber laser or a YAG laser, the window 13 may include quartz glass.

[0110] On the upper surface of the chamber 11, a pollution prevention device 15 is provided in a manner covering the window 13. The pollution prevention device 15 includes a cylindrical frame and a cylindrical diffusion member arranged in the frame. An inert gas supply space is provided between the frame and the diffusion member. In addition, an opening is provided on the bottom surface of the diffusion member. A large number of fine holes are provided on the peripheral wall of the diffusion member. Clean inert gas is introduced into the inert gas supply space and supplied to the diffusion member through the fine holes. The clean inert gas fills the diffusion member and is ejected downward. In this way, smoke is prevented from adhering to the window 13.

[0111] In addition, the irradiation device 4 of the present embodiment is configured to irradiate the laser light L to form the solidified layer 95, but the irradiation device 4 may also irradiate an electron beam. For example, the irradiation device 4 may also be configured to have: a cathode electrode that emits electrons, an anode electrode that gathers and accelerates the electrons, a solenoid that forms a magnetic field to gather the direction of the electron beam in one direction, and a collector that is electrically connected to the material layer 93 as the irradiated body and applies a voltage between the cathode electrode and the collector.

[0112] The cutting device 5 performs cutting processing on the solidified layer 95. The cutting device 5 includes: a processing head 51, which is arranged in the molding chamber 11a and has a built-in spindle 53; an X-axis drive device 55, which moves the processing head 51 along a predetermined horizontal direction, namely, the X-axis direction; a Y-axis drive device 57, which moves the processing head 51 along a horizontal direction orthogonal to the X-axis direction, namely, the Y-axis direction; and a Z-axis drive device 59, which moves the processing head 51 along a vertical direction, namely, the Z-axis direction. The spindle 53 is configured to be rotatable by mounting a cutting tool such as an end mill. By using this cutting device 5, the surface or non-main part of the solidified layer 95 can also be cut during the molding process of the three-dimensional object.

[0113] The inert gas supply and exhaust mechanism supplies inert gas to the chamber 11 and exhausts the inert gas including smoke to maintain the chamber 11 in a clean state. The inert gas supply and exhaust mechanism includes an inert gas supply device 17, an electric dust collector 6, a supply port 21a, a supply port 21b, a supply port 21c, a supply port 21d, a supply port 21e, an exhaust port 22a, an exhaust port 22b, an exhaust port 22c, a partition plate 23a, an upper guide plate 23b, a lower guide plate 23c, a fan 23d, a rectifying plate 23e, and pipes connecting the various parts.

[0114] The inert gas supply device 17 supplies an inert gas of a specified concentration to the chamber 11. The inert gas supply device 17 is, for example, an inert gas generating device that extracts inert gas from the surrounding air or a gas cylinder storing inert gas. The inert gas supply device 17 of this embodiment has a first inert gas supply device 171 and a second inert gas supply device 172. Ideally, the first inert gas supply device 171 is capable of supplying an inert gas with a higher concentration than the second inert gas supply device 172. In this embodiment, the first inert gas supply device 171 is a pressure swing adsorption (PSA) type nitrogen generating device, and the second inert gas supply device 172 is a membrane separation type nitrogen generating device. In addition, the inert gas supply device 17 may also include an inert gas supply device. Inert gas refers to a gas that does not substantially react with the material layer 93 or the solidified layer 95, and an appropriate gas can be selected from nitrogen, argon, helium, etc. according to the type of material powder.

[0115] The electric precipitator 6 removes most of the mist from the inert gas exhausted from the chamber 11, and then returns the inert gas to the chamber 11. The detailed structure of the electric precipitator 6 will be described later.

[0116] The supply port 21a is provided on one side of the recoater head 33. The supply port 21b is provided on a pipe laid on the end surface of the base table 31 opposite to the side where the supply port 21a is provided. The supply port 21a and the supply port 21b are respectively connected to the first inert gas supply device 171. Inert gas is selectively supplied to the chamber 11 through the supply port 21a or the supply port 21b according to the moving position of the recoater head 33. That is, when the supply port 21a is at a position facing the forming area, the inert gas is supplied through the supply port 21a, and when the supply port 21a is at a position not facing the forming area, the inert gas is supplied through the supply port 21b. The supply port 21c is provided on the side wall of the chamber 11 on the side where the supply port 21b is provided. The supply port 21c is connected to the electric precipitator 6, and the inert gas from which most of the smoke is removed by the electric precipitator 6 is returned to the chamber 11 through the supply port 21c. The supply port 21d is provided on the upper surface of the chamber 11 and is connected to the first inert gas supply device 171. The inert gas is supplied to the inert gas supply space of the pollution prevention device 15 through the supply port 21d. The supply port 21e is provided at the upper portion of the drive chamber 11b and is connected to the second inert gas supply device 172. The inert gas supplied from the second inert gas supply device 172 to the drive chamber 11b is supplied to the inside of the build chamber 11a through the connecting portion between the build chamber 11a and the drive chamber 11b.

[0117] A partition plate 23a is provided so as to cover the side wall of the chamber 11 on the opposite side to the side where the supply port 21b and the supply port 21c are provided. A discharge port 22a is provided on the upper surface of the chamber 11 in the space partitioned by the partition plate 23a and the side wall, and a discharge port 22b is provided on the upper surface of the chamber 11 on the molding area side near the partition plate 23a. Furthermore, an upper guide plate 23b extending in an L-shaped cross section is provided on the partition plate 23a side below the discharge port 22b so as to surround the discharge port 22b. A lower guide plate 23c whose lower portion extends to the molding area side is provided at the lower end of the partition plate 23a, and a predetermined gap is formed between the partition plate 23a and the lower guide plate 23c. The gap is located at a height lower than the center of the molding chamber 11a. Near the gap, there are multiple fans 23d that suck inert gas into the space separated by the partition plate 23a and the side wall, and at both ends of each fan 23d, there are rectifier plates 23e extending upward. The inert gas sent to the vicinity of the partition plate 23a is sent to the exhaust port 22a from the gap or under the lower guide plate 23c through the space separated by the partition plate 23a and the side wall. Moreover, the inert gas that is not completely recovered from the gap rises along the partition plate 23a, is guided by the upper guide plate 23b, and is sent to the exhaust port 22b. The exhaust port 22c is provided on the side of the recoating machine head 33 on the side where the supply port 21a is not provided. Through the exhaust port 22a, the exhaust port 22b and the exhaust port 22c, the inert gas is discharged from the chamber 11 and sent to the electrostatic precipitator 6.

[0118] The above-described structure of the inert gas supply and exhaust mechanism is only an example, and the positions, shapes, and numbers of the supply ports for supplying inert gas to the chamber 11 and the exhaust ports for exhausting inert gas from the chamber 11 may be arbitrarily configured as long as the inert gas can be appropriately supplied and exhausted.

[0119] Here, the structure of the electric precipitator 6 of this embodiment is described. Figure 6 As shown, the electric precipitator 6 includes a frame 61, a gas inlet 62, a charged part 63, a dust collecting part 64, a cleaning device 7, a bucket 65, a magnetic filter 8, an ozone removal filter 66, a fan 68 and a gas outlet 69. The electric precipitator 6 of this embodiment is a so-called one-stage (Cottrell type) dry electric precipitator in which the charged part 63 and the dust collecting part 64 are formed integrally. In addition, hereinafter, upstream and downstream are defined along the flow direction of the gas (inactive gas). In other words, the place relatively close to the gas inlet 62 in the electric precipitator 6 is called the upstream side, and the place relatively close to the gas outlet 69 in the electric precipitator 6 is called the downstream side.

[0120] The gas inlet 62 is provided in the housing 61 and connected to the exhaust ports 22a, 22b, and 22c. The gas containing dust, that is, the inert gas containing mist exhausted from the chamber 11 is supplied to the gas inlet 62 and sent into the housing 61.

[0121] The charging section 63 and the dust collecting section 64 are integrally formed and are disposed in the frame 61. Figure 6 as well as Figure 7 As shown, a plurality of positive plates 642 are provided at predetermined intervals, and a plurality of needle-shaped charged electrodes 631 are respectively mounted on the positive plates 642. The positive plates 642 and the charged electrodes 631 can be positively charged by a voltage supply component not shown. A dust collecting plate 641 is respectively provided in each interval of the positive plates 642. The dust collecting plate 641 is connected to the ground and is configured to be rotatable.

[0122] The inert gas containing smoke supplied from the gas inlet 62 is sent to the charging section 63. The charging electrode 631 in the charging section 63 positively charges the smoke in the inert gas by corona discharge. In the dust collecting section 64, the positively charged smoke repels the positive electrode plate 642 due to the Coulomb force and is pulled to the dust collecting plate 641 and collected.

[0123] The inert gas from which the smoke is removed by the dust collecting section 64 is sent to the gas outlet 69 through the magnetic filter 8 and the ozone removal filter 66. The gas outlet 69 is provided in the frame 61 and connected to the supply port 21c. In this way, the inert gas from which the smoke is removed is discharged from the electric dust collector 6 and returned to the chamber 11.

[0124] In addition, in this embodiment, the charging part 63 is configured to charge the mist as dust positively, but it may be configured to charge negatively. Also, a metal thin wire or brush-shaped electrode may be used instead of the needle-shaped charging electrode 631.

[0125] The cleaning device 7 removes the smoke as dust from at least one of the charging part 63 and the dust collecting part 64 to restore its collection capacity, so that the electric dust collector 6 can be used continuously for a long time. The cleaning device 7 of this embodiment includes: a charging part cleaning device 71 to remove the smoke attached to the charging part 63; and a dust collecting part cleaning device 73 to remove the smoke attached to the dust collecting part 64.

[0126] The charged part cleaning device 71 has, for example, a nozzle 711 and an intermittent ejection control unit 712. The nozzle 711 is disposed above the charged electrode 631, and gas is ejected from the nozzle 711 toward the charged electrode 631, thereby being able to remove the smoke attached to the charged electrode 631 of the charged part 63. In order to maintain the chamber 11 in a prescribed inert gas environment, it is ideal that the gas ejected from the nozzle 711 is the same gas as the inert gas supplied to the chamber 11. In this embodiment, a branch pipe 19 is provided between the supply port 21a, the supply port 21b, the supply port 21d and the first inert gas supply device 171, and the inert gas is supplied to the nozzle 711 from the first inert gas supply device 171 via the branch pipe 19. Moreover, it is ideal that the nozzle 711 is made of a non-conductive raw material such as resin to prevent a short circuit between the nozzle 711 and the charged electrode 631 and the positive plate 642. Furthermore, it is desirable to configure such that a wide range of the charged electrode 631 can be cleaned with a small number of nozzles 711. For example, as the nozzle 711, Figure 6 as well as Figure 8 As shown by the dotted arrow in , a fan-shaped nozzle is used to spray the inactive gas in a fan-shaped manner so as to cover the entire charged electrode 631. The intermittent spraying control unit 712 controls to intermittently spray the inactive gas from the nozzle 711. By spraying the inactive gas intermittently, a larger flow rate of inactive gas than that in continuous spraying can be intermittently sprayed toward the charged electrode 631, thereby improving the cleaning efficiency. In addition, the inactive gas used for cleaning can be saved.

[0127] The dust collecting section cleaning device 73 includes, for example, a plate-shaped scraper 731 disposed close to or adjacent to the side of the dust collecting plate 641, and a motor (not shown) for rotating the dust collecting plate 641. When the dust collecting plate 641 of the dust collecting section 64 is cleaned, the dust collecting plate 641 is rotated by the motor (not shown), and the attached smoke is scraped off by the scraper 731.

[0128] The smoke removed by the charging section cleaning device 71 and the dust collecting section cleaning device 73 falls into the storage hopper 65 provided below the charging section 63 and the dust collecting section 64 .

[0129] The charged part cleaning device 71 and the dust collecting part cleaning device 73 are not limited to the above structure. For example, the charged part cleaning device 71 of the present embodiment has a nozzle 711 as a fan-shaped nozzle that ejects inert gas in a fan-shaped manner, but it can also be replaced by a configuration in which the charged part cleaning device 71 has a nozzle that is arranged above each column of the charged electrode 631 and ejects the inert gas in a straight line toward the charged electrode 631. Moreover, the dust collecting part cleaning device 73 may also have a nozzle that ejects inert gas to the dust collecting plate 641, and may also have a beating device that vibrates the dust collecting plate 641. Moreover, the cleaning device 7 may also include only one of the charged part cleaning device 71 and the dust collecting part cleaning device 73.

[0130] When cleaning is performed by the cleaning device 7, it is desirable to temporarily stop charging the positive electrode 642 and the charging electrode 631. At this time, the dust collecting capability is temporarily reduced, so it is desirable that the solidified layer 95 is not formed in the stacking forming device 1 during cleaning. In other words, it is desirable that the cleaning device 7 cleans the charging portion 63 or the dust collecting portion 64 when the solidified layer 95 is not formed, for example, when the material layer 93 is formed or when the solidified layer 95 is cut.

[0131] Here, the structures of the magnetic filter 8 and the ozone removal filter 66 are described in detail. The magnetic filter 8 is provided in the frame 61 on the downstream side of the dust collecting section 64. The ozone removal filter 66 is provided in the frame 61 on the downstream side of the magnetic filter 8.

[0132] The magnetic filter 8 has a plurality of magnet plates 81, and the plurality of magnet plates 81 are arranged at predetermined intervals. When the dust is a magnetic body, the dust that is not completely captured by the dust collecting section 64 or the dust that is secondary scattered when the cleaning device 7 is cleaning is captured by the magnet plates 81 by means of magnetic force when passing between the magnet plates 81. In this way, the secondary scattered dust is prevented from adhering to the ozone removal filter 66 located downstream of the magnetic filter 8 and causing clogging. In addition, it is preferred that the magnet plates 81 adjacent to each other in the plurality of magnet plates 81 are arranged in a manner that different polarities are opposite to each other. In other words, in each magnet plate 81, the directions of the N pole and the S pole are unified into one direction. In this way, the magnetic flux density between the magnet plates 81 can be increased, so that the dust can be better captured.

[0133] Moreover, the plurality of magnet plates 81 are arranged so that the downstream side is inclined downward at the upper side than the center, and the downstream side is inclined upward at the lower side than the center. Specifically, in the present embodiment, the magnetic filter 8 has six magnet plates 81, and the three magnet plates 81 located at the upper side than the center are arranged in a manner that the downstream side is inclined downward, and the three magnet plates 81 located at the lower side than the center are arranged in a manner that the downstream side is inclined upward. By arranging the magnet plates 81 in this way, the magnetic filter 8 acts as a rectifying plate relative to the ozone removal filter 66. That is, the gas that has passed through the magnet plates 81 is diffused and is supplied to a wider area in the filtering area of ​​the ozone removal filter 66 in a roughly uniform manner. As a result, it is possible to prevent the ozone removal filter 66 from being locally deteriorated, thereby extending the life of the ozone removal filter 66.

[0134] To facilitate maintenance, Fig. 9 As shown, the magnetic filter 8 and the ozone removal filter 66 may also be mounted on a frame 83 that is detachably mounted from the frame body 61. The frame 83 is formed with a cutout 831 through which the magnet plate 81 can be inserted, and the magnet plate 81 is inserted into the cutout 831 and mounted on the frame 83. For example, by making the frame 83 include a magnetic body, the magnet plate 81 can be fixed to the frame 83 by magnetic force, and the mounting and removal of the magnet plate 81 becomes easy.

[0135] The magnet plate 81 of this embodiment is composed of a permanent magnet 811. More specifically, Fig.10 As shown, each magnet plate 81 has a permanent magnet 811 and a housing 812 containing a magnetic body that holds the permanent magnet 811. According to this structure, dust can be prevented from directly adhering to the permanent magnet 811, and dust adhering to the housing 812 can be easily removed by removing the permanent magnet 811 from the housing 812.

[0136] The ozone removal filter 66 removes ozone that may be generated during corona discharge from the gas. The ozone removal filter 66 is formed by filling an ozone decomposition catalyst such as activated carbon or manganese dioxide or nickel oxide in a carrier having a honeycomb structure. Ozone that has passed through the ozone removal filter 66 is decomposed by the activated carbon or the ozone decomposition catalyst.

[0137] The fan 68 sends out the gas inside the electric dust collector 6 to generate airflow, so that the gas circulates efficiently. The fan 68 can be set at any position in the frame 61, but in order to prevent pollution caused by dust and degradation caused by ozone, it is ideally set at the downstream side of the ozone removal filter 66. In addition, when cleaning is performed using the cleaning device 7, the fan 68 is stopped.

[0138] As described above, dust and ozone are removed from the gas supplied from the gas inlet 62 and the gas is discharged from the gas outlet 69 .

[0139] Here, Fig.11 The electric precipitator 6 of the modified example shown will be described. Fig.11 In the present invention, the same symbols are given to the same or equivalent components as the structures shown in the above embodiment, and detailed descriptions are omitted.

[0140] The electric precipitator 6 of the modified example is a so-called two-stage (Penny type) dry electric precipitator in which the charging part 63 and the dust collecting part 64 are independently formed. That is, the electric precipitator 6 may also include: the charging part 63, in which the positively charged needle-shaped charging electrode 631 and the opposite electrode 632 connected to the ground are arranged oppositely; and the dust collecting part 64, in which the positively charged positive electrode plate 642 and the dust collecting plate 641 connected to the ground are alternately provided. In addition, the charging part 63 may also be configured to make the smoke as dust negatively charged.

[0141] The plurality of magnet plates 81 of the modified example each have an electromagnet. By energizing the electromagnet to generate a magnetic field, dust that is a magnetic body can be removed. In addition, when the magnet plate 81 includes an electromagnet, it is ideally configured such that an oxygen concentration meter 67 for measuring the oxygen concentration of the gas is provided in the frame 61 on the downstream side of the dust collecting section 64, and when the oxygen concentration of the gas is higher than the limit oxygen concentration for dust ignition, the electromagnet is not energized.

[0142] Although some examples have been specifically shown, the present invention is not limited to the configurations of the embodiments shown in the drawings, and various modifications and applications are possible within the scope of the technical concept of the present invention.

Claims

1. An electric dust collector, comprising: Frame; A gas inlet is provided in the frame and supplies gas containing dust as a magnetic body; A charging unit, disposed in the frame, charges the dust positively or negatively; A dust collecting unit is disposed in the frame and collects the charged dust; a cleaning device, provided in the frame, including at least one of a charging part cleaning device for removing the dust attached to the charging part and a dust collecting part cleaning device for removing the dust attached to the dust collecting part; A magnetic filter is disposed in the frame at a downstream side of the dust collecting portion; an ozone removal filter, disposed in the frame on a downstream side of the magnetic filter, for removing ozone from the gas; as well as A gas outlet is provided on the frame body to discharge the gas from which the dust and the ozone have been removed. The magnetic filter has a structure configured in the following manner, that is, multiple magnet plates are arranged at predetermined intervals, and in each magnet plate located above the center, each downstream side is inclined downward, and in each magnet plate located below the center, each downstream side is inclined upward.

2. The electric precipitator according to claim 1, wherein Each of the plurality of magnet plates includes a permanent magnet and a housing that holds the permanent magnet and includes a magnetic body.

3. The electric precipitator according to claim 1, wherein The plurality of magnet plates each have an electromagnet.

4. The electric dust collector according to claim 3, further comprising: an oxygen concentration meter, disposed in the frame at a downstream side of the dust collecting section, for measuring the oxygen concentration of the gas; The electromagnet is configured not to be energized when the oxygen concentration of the gas is higher than the limit oxygen concentration for ignition of the dust.

5. The electric precipitator according to claim 1, wherein The plurality of magnet plates are arranged so that adjacent magnet plates have different polarities facing each other.

6. The electric dust collector according to claim 1, further comprising: The frame holds the magnetic filter and the ozone removing filter and is configured to be detachable from the frame body.

7. The electric precipitator according to claim 6, wherein The frame has cutouts through which the plurality of magnet plates can be inserted, and the plurality of magnet plates are inserted through the cutouts and fixed to the frame by magnetic force.

8. The electric precipitator according to claim 1, wherein The ozone removal filter contains activated carbon or an ozone decomposition catalyst.

9. The electric dust collector according to claim 1, further comprising: The fan is provided on the downstream side of the ozone removing filter in the housing and sends out the gas.

10. A stacking forming device, comprising the electric precipitator of claim 1, wherein The stacking forming device comprises: A chamber covering a specified shaping area and filled with an inert gas at a specified concentration; an irradiation device for irradiating the material layer formed in the forming area with laser light or electron beam to form a solidified layer; a supply port for supplying the inert gas to the chamber; an exhaust port for exhausting the inert gas from the chamber; and an inert gas supply device for supplying the inert gas to the supply port, The gas is the inert gas, The dust is smoke generated when the solidified layer is formed. The inert gas exhausted from the exhaust port is sent to the electric precipitator, and after the mist is removed, the inert gas is returned to the supply port.

11. The stacking forming device according to claim 10, wherein The stacked forming device further includes a cutting device for cutting the solidified layer.

12. The stacking forming device according to claim 10, wherein The cleaning device cleans the charging section or the dust collecting section when the formation of the solidified layer is not being performed.

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