1. A brush unit for use in a moving electrode type electrostatic precipitator, comprising: a rib that is arranged on an outer peripheral surface of a shaft in a longitudinal direction of the shaft; a brush that is formed by a plurality of brush wires clamped and fixed by a band-shape body; a fixture that allows the band-shape body to be sandwiched between the fixture and the rib; and a fastening unit that detachably fastens the rib and the fixture in a state in which the band-shape body is sandwiched between the rib and the fixture.

2. The brush unit for use in the moving electrode type electrostatic precipitator according to Claim 1, wherein the fixture includes a notch, and the band-shape body engages into the notch.

3. The brush unit for use in the moving electrode type electrostatic precipitator according to Claim 1, wherein an edge of the band-shape body to which the brush wires are attached is exposed outside peripheries of the rib and the fixture.

4. The brush unit for use in the moving electrode type electrostatic precipitator according to Claim 2, wherein the band-shape body, in a portion of a cross-sectional shape thereof, includes a cornered portion, the notch in the fixture is of a shape that is complementary to the cornered portion, and the cornered portion of the band-shape body engages into the notch of the fixture.

5. The brush unit for use in the moving electrode type electrostatic precipitator according to Claim 1, wherein a cross section of the fixture in a direction perpendicular to a direction in which the brush wires extend is channel-shaped.

6. The brush unit for use in the moving electrode type electrostatic precipitator according to Claim 1, wherein the fastening unit includes a bolt and a nut, and through holes are provided in the rib and the fixture so as to insert the bolt.

7. A moving electrode type electrostatic precipitator including the brush unit according to any one of Claims 1 to 6.

TECHNICAL FIELD

[0001] The present invention relates to a brush unit that scrapes off dust by making contact with a surface of a dust collecting electrode plate for use in a moving electrode type electrostatic precipitator, and such a moving electrode type electrostatic precipitator.

BACKGROUND ART

[0002] Moving electrode type electrostatic precipitators and such-like are conventionally deployed in thermal power plants as a device to remove dust such as soot resulting from exhaust gases emitted due to combustion. In a typical moving electrode type electrostatic precipitator, a dust collecting electrode includes a plurality of dust collecting electrode plates. The dust collecting electrode plates are connected to a chain to form a loop. The dust collecting electrode plates are rotated so that the dust can be scraped off the surfaces of the dust collecting electrode plates between a pair of brush units that are arranged on a rotation path. Each brush unit is formed by clamping a plurality of brush wires with an elongated band-shape body. The band-shape body is coupled to a rotary shaft. Conventionally, the band-shape body and the rotary shaft are coupled by welding the band-shape body directly to the rotary shaft or by first welding the band-shape body to a flat plate and then coupling the flat plate to a rib arranged on the rotary shaft (see Cited Document 1). Conventional Art Documents Patent Documents

[0003] Patent Document 1: Japanese Patent Application Laid-open No. H9-313253

DISCLOSURE OF INVENTION PROBLEM TO BE SOLVED BY THE INVENTION

[0004] As explained above, the band-shape body and the rotary shaft are coupled by welding. However, because the brush wires are made of metal such as stainless steel and have a thickness of 0.5 millimeters (mm) or less, the heat at the time of welding the band-shape body damages the brush wires, leading to degradation of the brush wires. Consequently, the brush wires tend to break easily, resulting in a decreased life.

[0005] It is an object of the present invention to provide a solution to the above problem and to provide a brush unit with brush wires that have a long life, and a moving electrode type electrostatic precipitator incorporating such a brush unit.

MEANS FOR SOLVING THE PROBLEM

[0006] To realize the above object, a brush unit for use in a moving electrode type electrostatic precipitator according to an aspect of the present invention includes a rib that is arranged on an outer peripheral surface of a shaft in a longitudinal direction of the shaft; a brush that is formed by a plurality of brush wires clamped and fixed by a band-shape body; a fixture that allows the band-shape body to be sandwiched between the fixture and the rib; and a fastening unit that detachably fastens the rib and the fixture in a state in which the band-shape body is sandwiched between the rib and the fixture.

[0007] According to the above aspect of the present invention, the rib and the fixtures are detachably fastened by the fastening unit in a state in which the band-shape body is sandwiched between the rib and the fixture. Consequently, the brush wires are safe from damage by heat resulting from welding, etc., and therefore the life of the brush wires can be increased.

According to the above aspect of the present invention, the fixture preferably includes a notch, and the band-shape body engages into the notch.

[0008] According to the above aspect of the present invention, the band-shape body can be immovably fixed between the rib and the fixtures.

According to the above aspect of the present invention, an edge of the band-shape body to which the brush wires are attached is preferably exposed outside peripheries of the rib and the fixture.

[0009] According to the above aspect of the present invention, the brush wires do not make contact with the rib or the fixture. Therefore, the brush wires are not subjected to any major bending that would have otherwise occurred at the contact region. Consequently, a bending stress on the brush wires can be reduced, and thereby the life of the brush wires can be increased.

According to the above aspect of the present invention, the band-shape body, in a portion of a cross-sectional shape thereof, preferably includes a cornered portion, the notch in the fixture is of a shape that is complementary to the cornered portion, and the cornered portion of the band-shape body engages into the notch of the fixture.

According to the above aspect of the present invention, a cross section of the fixture in a direction perpendicular to a direction in which the brush wires extend is preferably channel-shaped.

According to the above aspect of the present invention, the fastening unit preferably includes a bolt and a nut, and through holes are provided in the rib and the fixture so as to insert the bolt.

[0010] According to another aspect of the present invention, a moving electrode type electrostatic precipitator includes the above brush unit. According to the above aspect of the present invention, the life of the brush wires can be increased, and the brush should be replaced less frequently. Consequently, a moving electrode type electrostatic precipitator that has a high operation ratio and is economical can be provided.

ADVANTAGES OF THE INVENTION

[0011] According to an embodiment of the present invention, a rib and fixtures are detachably fastened by a fastening unit in a state in which a band-shape body is sandwiched between the rib and the fixtures. Consequently, because brush wires are safe from damage by heat resulting from welding, etc., the life of the brush wires can be increased.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] FIG. 1 is an exploded perspective view of a brush unit according to an embodiment of the present invention;

FIG. 2 is a perspective view of a channel brush;

FIG. 3 is a side view of the brush unit according to the present embodiment;

FIG. 4 is a cross-sectional view of the brush unit according to the present embodiment;

FIG. 5 is a diagram of a pair of the brush units arranged so as to sandwich the two surfaces of a dust collecting electrode plate of a moving electrode type electrostatic precipitator;

FIG. 6 is a perspective view of a structure of a moving electrode;

FIG. 7 is a layout drawing of a lower portion of a plurality of moving electrodes included in the moving electrode type electrostatic precipitator.

DETAILED DESCRIPTION

[0013] Exemplary embodiments of brush units according to the present invention incorporated in a moving electrode type electrostatic precipitator are explained in detail below with reference to the accompanying drawings.

The moving electrode type electrostatic precipitator includes a plurality of moving electrodes that electrostatically collect dust.

[0014] FIG. 6 is a perspective diagram explaining a structure of a moving electrode 15. As shown in FIG. 6, the moving electrode 15 includes driving wheels 26 arranged in the upper portion and rollers 28 arranged in the lower portion. A pair of endless chains 30 is stretched across the driving wheels 26 and the rollers 28. A plurality of dust collecting electrode plates 32 are suspended vertically between the pair of endless chains 30. In this manner, the moving electrode 15 forms, as a whole, a loop. A shaft 34 of the driving wheels 26 is rotated by a driving mechanism (not shown). The rotation of the shaft 34 is conveyed to the endless chains 30 that are engaged with the driving wheels 26, causing the endless chains 30 to rotate. As the endless chains 30 rotate, the dust collecting electrode plates 32 suspended on the endless chains 30 also rotate.

[0015] FIG. 7 is a layout drawing of the lower portions of the plurality of moving electrodes 15 included in the moving electrode type electrostatic precipitator. The moving electrodes 15 are arranged side by side, forming loops. Each loop of the moving electrode 15 moves around an alternate discharge electrode 14. In the course of rotation, each dust collecting electrode plate 32, which is vertically suspended on the endless chains 30, descends and then is turned up at the position of the rollers 28 to ascend. A pair of brush units 50 is arranged at a position such that the dust collecting electrode plate 32, after ascending, is sandwiched from the two sides thereof by the brush units 50. The brush units 50 brush off the dust adhering to the surfaces of the dust collecting electrode plate 32 as the tips of brush wires 62 slide against the surfaces of the dust collecting electrode plate 32. Once the dust is cleaned by the brush units 50, the dust collecting electrode plate 32 ascends, captures, owing to the principle of electrostatic precipitation, the dust from the atmosphere in an electrical discharge zone located above, and thereafter descends again.

[0016] FIG. 5 is an enlarged view of the brush units 50 shown in FIG. 7. Each of the brush units 50 includes a channel brush 60 that extends in a width direction of the surface of the dust collecting electrode plate 32 (that is, in a depth direction from a viewer of the drawing), and a shaft 51 that supports the base of the channel brush 60 and that can adjust the position of the channel brush 60 by rotating such that the channel brush 60 makes contact with the surface of the dust collecting electrode plate 32. The channel brush 60 is arranged in contact with the dust collecting electrode plate 32 at a predetermined upwardly-slanting angle (in a movement direction of the dust collecting electrode plate 32) relative to the surface of the dust collecting electrode plate 32. When the channel brush 60 fails to be into contact with the dust collecting electrode plate 32 due to wearing out, the shaft 51 can be rotated to cause the channel brush 60 to slant more downwardly relative to the current orientation so as to bring into contact with the dust collecting electrode plate 32. The channel brush 60 is clamped between a rib 52 arranged in the shaft 51 and fixtures 54.

[0017] FIG. 1 is an exploded perspective view of the brush unit 50. FIG. 2 is a perspective view of the channel brush 60. FIG. 3 is an enlarged view of the brush unit 50 shown in FIG. 5. FIG. 4 is a cross-sectional view of the brush unit 50. The structure of the brush unit 50 is explained in detail with reference to the above drawings.

[0018] As shown in FIG. 1, the flat plate-shaped rib 52 is welded onto an outer peripheral surface of the shaft 51 in a longitudinal direction of the shaft 51. Through holes 52a are formed in a thickness direction of the rib 52 to insert bolts 57. The channel brush 60 is sandwiched between the rib 52 and the fixtures 54 arranged in a longitudinal direction of the rib 52.

[0019] As shown in FIG. 2, the channel brush 60 includes a band-shape body 63 that is a channel (grooved steel), and a plurality of the brush wires 62. The brush wires 62 are clamped by the band-shape body 63. The band-shape body 63 is made of, for example, stainless steel. The band-shape body 63 prior to clamping the brush wires 62 has a U-shaped cross section. Each brush wire 62 is a fine wire of stainless steel having a diameter of, for example, about 0.5 mm. The brush wires 62 are gathered in a bunch and folded in half around a core rod 61 to form a bent portion. The bent portion is inserted into the groove of the band-shape body 63 from an upper opening and arranged inside the groove. The upper edges of the band-shape body 63 are swaged to prevent the brush wires 62 from slipping out, and the portion above the bent portion of the brush wires 62 is clamped by pressure bonding. Consequently, the band-shape body 63 is shaped into a triangular base having a triangular cross section, and the brush unit 50 is provided with a triangular base.

[0020] Each of the fixtures 54, as shown in FIG. 1, is channel-shaped, and is arranged so as to form a U shape when viewed from above. That is, the fixture 54 is arranged so that its cross section in a direction perpendicular to the direction in which the brush wires 62 of the channel brush 60 extend is channel-shaped. A notch 54a is provided on the leading end of the U-shaped portion of the fixture 54. The notch 54a is so formed that the corner formed between the bottom surface and the slanting surface of the triangular base of the band-shape body 63 fits into the notch 54a. As shown in FIGS. 3 and 4, the bottom surface and the slanting surface of the triangular base of the band-shape body 63 are tightly fitted into and engaged with the notch 54a so that the channel brush 60 can be immovably fixed to the rib 52. A through hole 54b is provided in the middle of the fixture 54 to insert the bolt 57.

[0021] The bolts 57 are inserted from the rib 52 side into the through holes 52a of the rib 52 and the through holes 54b of the fixtures 54. Washers 55 are slipped over the bolts 57 from the fixture 54 side, and thereafter nuts 56 are screwed onto the bolts 57. In the present embodiment, the bolts 57 and the nuts 56 serve as a fastening unit for fastening the rib 52 and the fixtures 54 together. The fastening units need not be limited to the bolts 57 and the nuts 56. Any fastening unit that can detachably fasten without requiring application of heat, for example, set screws, hooks, an adhesive tape, and a binding band can be used

[0022] In a state of being fastened as described above, as shown in FIGS. 3 and 4, an edge 63a of the band-shape body 63 on a side to which the brush wires 62 are attached is exposed outside the peripheries of the rib 52 and the fixtures 54. Consequently, the brush wires 62 do not make contact with the peripheries of the rib 52 and the fixtures 54. Therefore, the brush wires 62 are not subjected to any major bending that would have occurred at the contact region. Consequently, a bending stress on the brush wires 62 can be reduced, and thereby the life of the brush wires 62 can be increased.

[0023] For replacing the channel brush 60 when the brush wires 62 are worn out, the old channel brush 60 can be removed by unfastening the nuts 56 and the bolts 57, and then a new channel brush 60 is inserted in place between the rib 52 and the fixtures 54, and fastened the rib 52 and the fixtures 54 with the bolts 57 and the nuts 56. In this way, when the brush wires 62 have worn out, the entire brush unit 50 needs not be replaced, but only the channel brush 60 needs to be replaced. Consequently, cost can be reduced.

[0024] As explained above, the brush unit 50 can be assembled without having to mount the channel brush 60 onto the shaft 51 or the rib 52 by welding. The brush wires 62 are therefore safe from damage by heat resulting from welding. Consequently, the life of the brush wires 62 can be increased. This requires the replacement of the channel brush 60 less frequently, and the trouble associated with the replacement of the channel brush 60 can be reduced. When the replacement is actually required, the entire brush unit need not be replaced. Consequently, a moving electrode type electrostatic precipitator that has a high operation ratio and is economical can be provided.

[0025] In the above embodiment, one brush unit 50 is mounted linearly in the longitudinal direction of the shaft 51; however, this is cited as an example, and the number of brush units 50 mounted on the shaft 51 can be determined as required. Furthermore, the brush units 50 can be arranged helically and the shaft 51 can be rotated by motor. In the above embodiment, a plurality of the fixtures 54 is used. However, the fixtures 54 that form an integrated unit can also be used.

EXPLANATIONS OF LETTERS OR NUMERALS

[0026] 14: Discharge electrode; 15: Moving electrode; 26: Driving wheel; 28: Roller; 30: Endless chain; 32: Dust collecting electrode plate; 34: Shaft; 50: Brush unit; 51: Shaft; 52: Rib; 52a: Through hole; 54: Fixtures; 54a: Notch; 54b: Through hole; 55: Washer; 56: Nut; 57: Bolt; 60: Channel brush; 61: Core rod; 62: Brush wires; 63: Band-shape body; 63a: Edge

WE CLAIM:

1. A brush unit for use in a moving electrode type electrostatic precipitator, comprising:

a rib that is arranged on an outer peripheral surface of a shaft in a longitudinal direction of the shaft;

a brush that is formed by a plurality of brush wires clamped and fixed by a band-shape body;

a fixture that allows the band-shape body to be sandwiched between the fixture and the rib; and

a fastening unit that detachably fastens the rib and the fixture in a state in which the band-shape body is sandwiched between the rib and the fixture.

2. The brush unit for use in the moving electrode type electrostatic precipitator according to Claim 1, wherein the fixture includes a notch, and the band-shape body engages into the notch.

3. The brush unit for use in the moving electrode type electrostatic precipitator according to Claim 1, wherein an edge of the band-shape body to which the brush wires are attached is exposed outside peripheries of the rib and the fixture.

4. The brush unit for use in the moving electrode type electrostatic precipitator according to Claim 2, wherein

the band-shape body, in a portion of a cross-sectional shape thereof, includes a cornered portion,

the notch in the fixture is of a shape that is complementary to the cornered portion, and

the cornered portion of the band-shape body engages into the notch of the fixture.

5. The brush unit for use in the moving electrode type electrostatic precipitator according to Claim 1, wherein a cross section of the fixture in a direction perpendicular to a direction in which the brush wires extend is channel-shaped.

6. The brush unit for use in the moving electrode type electrostatic precipitator according to Claim 1, wherein the fastening unit includes a bolt and a nut, and through holes are provided in the rib and the fixture so as to insert the bolt.

7. A moving electrode type electrostatic precipitator including the brush unit according to any one of Claims 1 to 6.