Generator motor dust collection device and method

Abstract

The invention discloses a power generation motor dust collecting device and method.The collecting device comprises dust collecting boxes (2) installed on the upper side and the lower side of a carbon brush (12) and an air suction pipe (3) installed on a brake (14), suction inlets (22) of the dust collecting boxes (2) correspond to the contact face of the carbon brush (12) and a collecting ring (11), and the annular surface of the collecting ring (11) is of a comb tooth structure; a suction inlet (22) of the air suction pipe (3) corresponds to the contact surface of the brake (14) and the brake ring (13); an exhaust port (23) of the dust collection box (2) is connected with the dual-purpose dust remover (4) through a carbon powder dust collection pipeline (21), an exhaust port (23) of the air suction pipe (3) is connected with the dual-purpose dust remover (4) through a braking dust collection pipeline (31), and an inlet of the dual-purpose dust remover (4) is provided with a switching assembly (5) for switching the carbon powder dust collection pipeline (21) and the braking dust collection pipeline (31). The invention has the characteristics of equipment space reduction and cost saving.

Description

Technical Field

[0001] The invention relates to a generator motor cleaning device, in particular to a generator motor dust collection device and method. Background Art

[0002] In a pumped-storage power station, when there is excess electricity in the power system, the generator motor operates as a motor, driving the water pump to pump water from downstream into the reservoir, converting the electrical energy into the potential energy of water and storing it. When the system is at peak load, the reservoir releases water, and the generator motor operates as a generator, using the potential energy of water to drive the turbine to rotate, thereby generating electricity for the power grid. Therefore, the generator motor plays a vital role in a pumped-storage power station and is one of the core equipment of a pumped-storage power station. It has dual functions: it can operate as a motor or a generator, and it operates frequently.

[0003] The generator motor is a synchronous motor, which mainly includes a stator, a rotor, an excitation system, a braking system, etc. Its rotor winding is connected to the excitation system through a collector ring carbon brush. During the rotation of the unit, the collector ring rubs against the carbon brush to produce carbon brush dust. This carbon brush dust will pollute the insulating parts in the collector ring chamber, resulting in reduced insulation of the rotor circuit. In severe cases, the rotor will be grounded at one point, causing the unit to stop operating and affecting economic benefits. At the same time, when the generator motor is mechanically braked, the brake will rub against the brake ring of the generator motor, and the brake gate will wear to produce gate dust, which will pollute the internal air duct of the generator motor and produce difficult-to-clean sludge after mixing with the oil mist, threatening the safe operation of the unit.

[0004] The existing dust collection method for generator motors only uses fans or other air blowing or dust collection devices to collect or transfer carbon brush dust, and can only perform dust collection operations on one position alone, and cannot perform dust collection on other positions of the generator motor. The dust collection range is relatively single. If two parts of the generator motor need to be dusted at the same time, two sets of dust collection equipment are required, which occupies a large area, has high energy consumption and high cost. Summary of the invention

[0005] The object of the present invention is to provide a dust collection device and method for a generator motor, which has the characteristics of reducing equipment space and saving costs.

[0006] The technical solution of the present invention: a dust collection device for a generator motor, comprising a dust box installed on the upper and lower sides of the carbon brush of the generator motor and an air suction pipe installed on the brake of the generator motor, the suction port of the dust box corresponds to the contact surface between the carbon brush and the collector ring, and the annular surface of the collector ring is a comb tooth structure; the suction port of the air suction pipe corresponds to the contact surface between the brake and the brake ring; the discharge port of the dust box is connected to the dual-purpose dust collector via a carbon powder dust suction pipeline, the discharge port of the air suction pipe is connected to the dual-purpose dust collector via a brake dust suction pipeline, and the inlet of the dual-purpose dust collector is provided with a switching component for switching the carbon powder dust suction pipeline and the brake dust suction pipeline.

[0007] In the aforementioned dust collection device for the generator motor, a windshield located on the left and right sides of the carbon brush is provided between the two dust collecting boxes.

[0008] In the aforementioned dust collection device for the generator motor, the inlets of the carbon dust suction pipeline and the brake dust suction pipeline are both provided with branch pipes, and blowers are provided on the branch pipes.

[0009] In the aforementioned dust collection device for the generator motor, the inlet of the dual-purpose dust collector includes a first inlet corresponding to the carbon powder dust suction pipeline and a second inlet corresponding to the brake dust suction pipeline, and the switching assembly includes a baffle located at the inlet, a switching motor is provided in the middle of the baffle, a through hole corresponding to the first inlet or the second inlet is provided on one side of the baffle, and the other side of the baffle is closed.

[0010] In the aforementioned dust collection device for the generator motor, an electrostatic adsorption device, a dust suction fan and a water washing tank are arranged in sequence inside the dual-purpose dust collector along the dust collection direction. A vibration motor is provided on the electrostatic adsorption device, and the dust suction fan is connected to the water washing tank via an exhaust pipe.

[0011] In the aforementioned dust collection device for the generator motor, the electrostatic adsorption device includes a mounting frame, on which a plurality of elastic isolation plates are provided along the dust flow direction, a mounting groove is formed between adjacent elastic isolation plates, a metal filter screen is provided on the mounting groove, two adjacent metal filter screens are alternately connected to the positive pole and the negative pole respectively, a first dust suction port is provided on the elastic isolation plate, and the mounting frame is provided with a second dust suction port at the bottom of the elastic isolation plate.

[0012] In the aforementioned dust collection device for the generator motor, a dust inlet and a sewage outlet are provided at the bottom of the water washing tank, a plurality of layers of partitions staggered left and right are provided inside the water washing tank, and a water mist nozzle connected to a water inlet pipe and a drainage pipe connected to a sedimentation tank are provided at the top of the water washing tank.

[0013] In the aforementioned dust collection device for the generator motor, a pair of electrostatic rollers and a static-eliminating roller are provided in the dust collection box, the electrostatic roller is close to the contact surface between the carbon brush and the collector ring, a dust collection belt is surrounded between the electrostatic roller and the static-eliminating roller; and a driving motor is provided on the electrostatic roller or the static-eliminating roller.

[0014] The collection method of the above-mentioned generator motor dust collection device includes: when the unit shutdown speed is not less than 40%, the switching component switches the carbon powder dust suction pipeline to open, the brake dust suction pipeline is closed, and the carbon brush dust generated by the friction between the carbon brush and the collector ring enters the dual-purpose dust collector through the carbon powder dust suction pipeline; when the unit shutdown speed is lower than 40%, the switching component switches the carbon powder dust suction pipeline to close, the brake dust suction pipeline to open, and the gate dust generated by the friction between the brake and the brake ring enters the dual-purpose dust collector through the brake dust suction pipeline.

[0015] In the aforementioned collection method, after the carbon brush dust or gate dust enters the dual-purpose dust collector, it first passes through the electrostatic adsorption device, and the dust enters from the metal filter of the positive electrode and flows out from the metal filter of the negative electrode. It is adsorbed on the metal filter under the action of static electricity, and then sent into the water washing tank from the bottom of the water washing tank by the dust suction fan. Through each layer of partition, the carbon brush dust or gate dust is mixed in the water, and further dust is removed by the water mist nozzle. Then the water flow containing dust in the water washing tank enters the sedimentation tank through the upper drain pipe. After sufficient sedimentation, the wastewater is discharged.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The carbon brush dust of the carbon brush in the generator motor of the present invention is sent to the dust collector through the carbon dust suction pipeline; the gate dust on the brake is sent to the dust collector through the brake dust suction pipeline, and the two are transported separately through separate pipelines without interfering with each other; a switching component is arranged inside the dust collector to switch the pipeline inlet, so that the two pipelines share a dual-purpose dust collector, and the dual-purpose dust collector is only connected to one pipeline at a time for dust removal processing, which can not only ensure the dust suction effect between the collector ring and the carbon brush and between the brake and the brake ring, but also reduce energy consumption, save equipment space and cost.

[0018] Therefore, the present invention has the characteristics of reducing equipment space and saving costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the present invention.

[0020] Figure 2 It is a schematic diagram of the installation structure of the carbon brush and the dust box.

[0021] Figure 3 It is a schematic diagram of the structure of the dust box.

[0022] Figure 4 It is a schematic diagram of the structure of the switching component and the metal filter.

[0023] Figure 5 It is a structural schematic diagram of an electrostatic adsorption device.

[0024] Figure 6It is a schematic diagram of the structure of the dust collecting belt.

[0025] The markings in the attached drawings are: 1, generator motor; 11, collector ring; 12, carbon brush; 13, brake ring; 14, brake; 2, dust box; 21, carbon powder suction pipeline; 22, suction port; 23, discharge port; 24, wind deflector; 25, electrostatic roller; 26, anti-static roller; 27, dust collecting belt; 3, suction pipe; 31, brake dust suction pipeline; 32, branch pipe; 33, blower; 4, dual-purpose dust collector; 41, first inlet; 4 2. Second inlet; 5. Switching assembly; 51. Baffle; 52. Switching motor; 53. Through hole; 6. Electrostatic adsorption device; 61. Mounting frame; 611. Elastic isolation plate; 62. Mounting slot; 63. Metal filter; 64. First dust suction port; 65. Second dust suction port; 7. Dust suction fan; 71. Exhaust duct; 8. Washing tank; 81. Partition; 82. Water mist nozzle; 83. Water inlet pipe; 84. Drain pipe; 85. Sedimentation tank. DETAILED DESCRIPTION

[0026] The present invention will be further described below in conjunction with the embodiments, but they are not intended to limit the present invention.

[0027] Example:

[0028] like Figure 1-Figure 6 As shown, the dust collection device for the generator motor comprises a dust box 2 installed on the upper and lower sides of the carbon brush 12 of the generator motor 1 and an air suction pipe 3 installed on the brake 14 of the generator motor 1, the suction port 22 of the dust box 2 corresponds to the contact surface between the carbon brush 12 and the collector ring 11, and the suction port 22 of the air suction pipe 3 corresponds to the contact surface between the brake 14 and the brake ring 13; the discharge port 23 of the dust box 2 is connected to the dual-purpose dust collector 4 through the carbon dust suction pipeline 21, and the discharge port 23 of the air suction pipe 3 is connected to the dual-purpose dust collector 4 through the brake dust suction pipeline 31, and the inlet of the dual-purpose dust collector 4 is provided with a switching component 5 for switching the carbon dust suction pipeline 21 and the brake dust suction pipeline 31. The annular surface of the collector ring 11 is a concave and convex comb tooth structure. The comb tooth structure is conducive to the formation of an air duct for absorbing carbon brush dust, which is beneficial to the collection efficiency of carbon brush dust. It can also improve the stiffness, strength and service life of the collector ring 11 while ensuring that the contact surface of the carbon brush 12 meets the current carrying capacity requirements, and is also beneficial to the ventilation and cooling of the collector ring 11 and the carbon brush 12.

[0029] The dust box 2 is distributed on the upper and lower sides of the carbon brush 12, and the suction port 22 corresponds to the contact surface between the carbon brush 12 and the collector ring 11; the suction pipe 3 is set on the brake 14 of the generator motor 1, and the suction port 22 corresponds to the contact surface between the brake 14 and the brake ring 13; thereby, the dust at the collector ring 11 and the brake ring 13 in the generator motor 1 can be collected respectively through the dust box 2 and the suction pipe 3, so as to better control the suction position, accurately absorb dust, and prevent dust from escaping.

[0030] The carbon brush dust of the carbon brush 12 in the generator motor 1 is sent to the dust collector through the carbon dust suction pipeline 21; the dust on the brake 14 is sent to the dust collector through the brake dust suction pipeline 31, and the two are transported separately through separate pipelines without interfering with each other; a switching component 5 is arranged inside the dust collector to switch the pipeline inlet, so that the two pipelines share a dual-purpose dust collector 4, and the dual-purpose dust collector 4 is only connected to one pipeline at a time for dust removal, which can not only ensure the dust suction effect between the collector ring 11 and the carbon brush 12 and between the brake 14 and the brake ring 13, but also reduce energy consumption, save equipment space and cost.

[0031] A windshield 24 is provided between the two dust collecting boxes 2 and is located on the left and right sides of the carbon brush 12. The windshield 24 is provided to cooperate with the dust collecting box 2 and surround the periphery of the carbon brush 12, so as to better collect the carbon brush dust and prevent the carbon brush dust from escaping.

[0032] The inlets of the carbon dust suction pipeline 21 and the brake dust suction pipeline 31 are both provided with a branch pipe 32, and a blower 33 is provided on the branch pipe 32. The carbon dust suction pipeline 21 and the brake dust suction pipeline 31 are regularly purged by the blower 33 to prevent the carbon dust suction pipeline 21 and the brake dust suction pipeline 31 from being blocked.

[0033] The inlet of the dual-purpose dust collector 4 includes a first inlet 41 corresponding to the carbon dust suction pipeline 21 and a second inlet 42 corresponding to the brake dust suction pipeline 31. The switching assembly 5 includes a baffle 51 located at the inlet, a switching motor 52 is provided in the middle of the baffle 51, a through hole 53 corresponding to the first inlet 41 or the second inlet 42 is provided on one side of the baffle 51, and the other side of the baffle 51 is closed. The baffle 51 rotates under the drive of the switching motor 52, thereby changing the position of the through hole 53; when the closed part of the baffle 51 blocks the first inlet 41, the through hole 53 is connected with the second inlet 42, the brake dust suction pipeline 31 is opened, and the carbon dust suction pipeline 21 is closed; when the closed part of the baffle 51 blocks the second inlet 42, the through hole 53 is connected with the first inlet 41, the carbon dust suction pipeline 21 is opened, and the brake dust suction pipeline 31 is closed, and the switching is convenient and flexible.

[0034] The interior of the dual-purpose dust collector 4 is provided with an electrostatic adsorption device 6, a dust suction fan 7 and a water washing tank 8 in sequence along the dust collection direction. The electrostatic adsorption device 6 is provided with a vibration motor, and the dust suction fan 7 is connected to the water washing tank 8 via an exhaust pipe 71. The dust entering the dual-purpose dust collector 4 is adsorbed by the electrostatic adsorption device 6, and the vibration motor vibrates the electrostatic adsorption device 6 to remove the dust deposited on the electrostatic adsorption device 6, clean the electrostatic adsorption device 6, and maintain the long-term electrostatic adsorption of the electrostatic adsorption device 6. The dust passing through the electrostatic adsorption device 6 is introduced into the water washing tank 8 by the exhaust pipe 71 for sedimentation to prevent the dust from escaping to the external environment.

[0035] The electrostatic adsorption device 6 includes a mounting frame 61, on which a plurality of elastic isolation plates 611 are arranged along the dust flow direction, a mounting groove 62 is formed between adjacent elastic isolation plates 611, a metal filter screen 63 is arranged on the mounting groove 62, two adjacent metal filter screens 63 are respectively alternately connected to the positive and negative poles of the high-voltage DC power supply, a first dust suction port 64 is arranged on the elastic isolation plate 611, and a second dust suction port 65 is arranged at the bottom of the elastic isolation plate 611 of the mounting frame 61. Dust enters from the metal filter screen 63 connected to the positive pole and flows out from the metal filter screen 63 connected to the negative pole, and is adsorbed on the metal filter screen 63 under the action of static electricity, and the metal filter screen 63 is subjected to multi-layer adsorption through multiple layers of metal filter screens 63 with alternately distributed positive and negative poles, which can effectively improve the adsorption effect. The elastic isolation plate 611 can be bent to adjust the installation angle of the metal filter 63 to better absorb, block and filter the dust; when the metal filter 63 is cleaned, the dust attached to the metal filter 63 can be removed by vibrating the metal filter 63 with a vibration motor or by cutting off the power, and then the dust is sucked away through the first dust suction port 64 and the second dust suction port 65 by the dust suction fan 7, thereby achieving a good cleaning effect.

[0036] The bottom of the water washing tank 8 is provided with a dust inlet and a sewage outlet, and the inside of the water washing tank 8 is provided with a plurality of layers of partitions 81 staggeredly distributed left and right. The top of the water washing tank 8 is provided with a water mist nozzle 82 connected to the water inlet pipe 83 and a drainage pipe 84 connected to the sedimentation tank 85. The dust enters the water washing tank 8 from the dust inlet, and is fully in contact with water in the water washing tank 8. The partitions 81 provided in the water washing tank 8 form a winding water channel in the water washing tank 8, which prolongs the contact time between the dust and the water body, increases the contact area, and improves the dust settling effect. At the same time, the water mist nozzle 82 sprays water mist on the dust scattered on the top, so that the dust particles condense and settle in the water washing tank 8, which is conducive to the capture of the escaped dust.

[0037] The water washing tank 8 and the sedimentation tank 85 are provided to protect the environment, reduce air pollution, and avoid direct gas discharge into the factory, which may cause damage to the respiratory system of workers.

[0038] A pair of electrostatic rollers 25 and a static-eliminating roller 26 are provided in the dust collecting box 2. The electrostatic roller 25 is close to the contact surface between the carbon brush 12 and the collector ring 11. A dust collecting belt 27 is surrounded between the electrostatic roller 25 and the static-eliminating roller 26. A driving motor is provided on the electrostatic roller 25 or the static-eliminating roller 26 to drive the electrostatic roller 25 or the static-eliminating roller 26 to rotate. The electrodes of the electrostatic roller 25 in the dust collecting box 2 located on the upper side of the carbon brush 12 and the electrostatic roller in the dust collecting box 2 located on the lower side of the carbon brush 12 are opposite.

[0039] A high-voltage electrostatic field is generated by connecting the electrostatic roller 25 to the electrode, so that the dust collector wrapped around the electrostatic roller 25 is electrostatically charged, and the carbon brush dust is polarized to show positive and negative charges respectively, and adsorbed on the dust collecting belt 27. As the driving motor drives the electrostatic roller 25 or the anti-static roller 26 to rotate, the dust collecting belt 27 rotates. When the dust collecting belt 27 adsorbed with carbon brush dust is transferred to the anti-static roller 26, the anti-static roller 26 eliminates the static electricity on the dust collecting belt 27, so that the carbon brush dust is separated from the dust collecting belt 27 and is sucked into the dual-purpose dust collector 4 by the dust collecting box 2 and the carbon powder suction pipeline 21.

[0040] The collection method of the above-mentioned dust collection device includes: when the unit shutdown speed is not less than 40%, the switching component 5 switches the carbon powder dust suction pipeline 21 to open, and the brake dust suction pipeline 31 to close, and the carbon brush dust generated by the friction between the carbon brush 12 and the collector ring 11 enters the dual-purpose dust collector 4 through the carbon powder dust suction pipeline 21; when the unit shutdown speed is lower than 40%, the switching component 5 switches the carbon powder dust suction pipeline 21 to close, and the brake dust suction pipeline 31 to open, and the gate dust generated by the friction between the brake 14 and the brake ring 13 enters the dual-purpose dust collector 4 through the brake dust suction pipeline 31.

[0041] After the carbon brush dust or gate dust enters the dual-purpose dust collector 4, it first passes through the electrostatic adsorption device 6, and the dust enters from the metal filter 63 of the positive electrode and flows out from the metal filter 63 of the negative electrode. Under the action of static electricity, it is adsorbed on the metal filter 63, and then sent into the water washing tank 8 from the bottom of the water washing tank 8 by the dust suction fan 7. Through each layer of partition 81, the carbon brush dust or gate dust is mixed in the water, and further dusted by the water mist nozzle 82. Then, the water flow containing dust in the water washing tank 8 enters the sedimentation tank 85 through the upper drain pipe 84. After sufficient sedimentation, the wastewater is discharged.

[0042] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. For those skilled in the art, the technical solutions described in the above embodiments can be modified, or some of the technical features therein can be replaced by equivalents; and all these modifications and replacements should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A dust collection device for a generator motor, characterized in that: The invention comprises a dust collecting box (2) installed on the upper and lower sides of a carbon brush (12) and an air suction pipe (3) installed on a brake (14); the suction port (22) of the dust collecting box (2) corresponds to the contact surface between the carbon brush (12) and a collector ring (11); the annular surface of the collector ring (11) is a comb tooth structure; the suction port (22) of the air suction pipe (3) corresponds to the contact surface between the brake (14) and the brake ring (13); the discharge port (23) of the dust collecting box (2) is connected to a dual-purpose dust collector (4) via a carbon dust suction pipeline (21); the discharge port (23) of the air suction pipe (3) is connected to the dual-purpose dust collector (4) via a brake dust suction pipeline (31); and the inlet of the dual-purpose dust collector (4) is provided with a switching component (5) for switching between the carbon dust suction pipeline (21) and the brake dust suction pipeline (31).

2. The dust collection device for a generator motor according to claim 1, characterized in that: A windshield plate (24) is provided between the two dust collection boxes (2) and is located on the left and right sides of the carbon brush (12).

3. The dust collection device for a generator motor according to claim 1, characterized in that: The inlets of the carbon powder suction pipeline (21) and the brake suction pipeline (31) are both provided with branch pipes (32), and a blower (33) is provided on the branch pipes (32).

4. The dust collection device for a generator motor according to claim 1, characterized in that: The inlet of the dual-purpose dust collector (4) comprises a first inlet (41) corresponding to the carbon powder suction pipeline (21) and a second inlet (42) corresponding to the brake dust suction pipeline (31); the switching component (5) comprises a baffle (51) located at the inlet; a switching motor (52) is provided in the middle of the baffle (51); a through hole (53) corresponding to the first inlet (41) or the second inlet (42) is provided on one side of the baffle (51); and the other side of the baffle (51) is closed.

5. The dust collection device for a generator motor according to claim 1, characterized in that: The interior of the dual-purpose dust collector (4) is provided with an electrostatic adsorption device (6), a dust suction fan (7) and a water washing tank (8) in sequence along the dust collection direction; a vibration motor is provided on the electrostatic adsorption device (6); and the dust suction fan (7) is connected to the water washing tank (8) via an exhaust pipe (71).

6. The dust collection device for the generator motor according to claim 5, characterized in that: The electrostatic adsorption device (6) comprises a mounting frame (61), a plurality of elastic isolation plates (611) are arranged on the mounting frame (61) along the dust flow direction, a mounting groove (62) is formed between adjacent elastic isolation plates (611), a metal filter screen (63) is arranged on the mounting groove (62), two adjacent metal filter screens (63) are respectively connected alternately to a positive electrode and a negative electrode, a first dust suction port (64) is arranged on the elastic isolation plate (611), and a second dust suction port (65) is arranged on the mounting frame (61) at the bottom of the elastic isolation plate (611).

7. The dust collection device for a generator motor according to claim 5, characterized in that: The bottom of the water washing tank (8) is provided with a dust inlet and a sewage outlet, the interior of the water washing tank (8) is provided with a plurality of layers of partitions (81) staggeredly distributed left and right, and the top of the water washing tank (8) is provided with a water mist nozzle (82) connected to a water inlet pipe (83) and a drainage pipe (84) connected to a sedimentation tank (85).

8. The dust collection device for a generator motor according to claim 1, characterized in that: A pair of electrostatic rollers (25) and a static-eliminating roller (26) are arranged in the dust collecting box (2); the electrostatic roller (25) is close to the contact surface between the carbon brush (12) and the collector ring (11); a dust collecting belt (27) is surrounded between the electrostatic roller (25) and the static-eliminating roller (26); and a driving motor is connected to the electrostatic roller (25) or the static-eliminating roller (26).

9. The dust collection method of the generator motor dust collection device according to any one of claims 1 to 8, characterized in that: The invention comprises the following steps: when the unit is stopped and the rotation speed is not less than 40%, the switching component (5) switches the carbon dust suction pipeline (21) to open and the brake dust suction pipeline (31) to close, and the carbon brush dust generated by the friction between the carbon brush (12) and the collector ring (11) enters the dual-purpose dust collector (4) through the carbon dust suction pipeline (21); when the unit is stopped and the rotation speed is less than 40%, the switching component (5) switches the carbon dust suction pipeline (21) to close and the brake dust suction pipeline (31) to open, and the gate dust generated by the friction between the brake (14) and the brake ring (13) enters the dual-purpose dust collector (4) through the brake dust suction pipeline (31).

10. The collection method according to claim 9, characterized in that: When the carbon brush dust or the gate dust enters the dual-purpose dust collector (4), it first passes through the electrostatic adsorption device (6), and the dust enters from the metal filter screen (63) of the positive electrode and flows out from the metal filter screen (63) of the negative electrode. Under the action of static electricity, the dust is adsorbed on the metal filter screen (63), and then sent into the water washing tank (8) from the bottom of the water washing tank (8) by the dust suction fan (7). Through each layer of partition (81), the carbon brush dust or the gate dust is mixed with water, and further dust is removed by the water mist nozzle (82). Then, the water flow containing dust in the water washing tank (8) enters the sedimentation tank (85) through the upper drainage pipe (84), and after sufficient sedimentation, it is discharged as waste water.

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