MOVING ELECTRODE TYPE ELECTRIC DUST COLLECTOR AND METHOD OF CARRYING IN PART THEREOF
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the carrying in replacement parts for a dry electric dust collector included in smoke control equipment used in power generation and other industries, and more particularly, to a moving electrode type electric dust collector using moving electrodes for dust collection and a method of carrying in parts of the dust collector.
2. Description of the Related Art
FIG. 1 outlines a construction of a general moving electrode type electric dust collector. An electric dust collector 1 includes a casing 2 in which a gas passage leading from a gas inlet 2a to a gas outlet 2b is formed and in which plural fixed electrodes 3 and moving electrodes 4 for dust collection are installed. A hopper 6 for receiving dust falling after being collected by the dust collecting electrodes is disposed below each of the fixed electrodes 3 and moving electrodes 4 with a discharge conveyer 7 provided to discharge the dust recovered from the hoppers. The hoppers 6 are each provided with a hopper grating 8 which prevents large objects to possibly clog up the discharge conveyer 7 from falling into the hopper and which can be used as footing for workers working in the casing.

FIG. 2 is an enlarged view of an example moving electrode of an electric dust collector. The moving electrode includes dust collecting electrode plates 9 which are shaped like rectangular strips and hung from a pair of endless chains 10 forming a loop. The dust collecting electrode plates 9 very slowly move with the chains 10 driven by a motor 11 for the dust collecting electrode plates and thereby collect dust contained in the gas in a dust collection zone 12 forming a gas passage. Reference numerals 16 and 17 denote upper and lower wheels around which the chains 10 are wound. The dust collected by the dust collecting plates 9 is brushed off by rotary brushes 15 which are installed in a dust non-collection zone 13 downward of the gas passage and turned by a rotary brush motor 14.
The construction of the moving electrodes will be described in detail with reference to FIG. 3. FIG. 3 is a partial sectional view taken along line A-A in the direction of the arrows shown in FIG. 2. As shown, there are multiple discharge electrodes 5 and plural moving electrodes 4 in the casing 2 . The discharge electrodes 5 are hung in a gas passage forming a dust collection zone 12. Each of the moving electrodes 4 includes plural dust collecting electrode plates 9 which are hung from a pair of endless chains 10 thereby forming a loop and which turn around the discharge electrodes 5 and a pair of brush units 15 which sandwich and brush the dust collecting electrode plates 9 at a predetermined position. The looped dust collecting electrode plates 9 of each of the moving

electrodes 4 are wound around the corresponding upper and lower wheels 16 and 17, so that the loop runs through the dust collection zone 12 and the dust non-collection zone 13. In the example shown in FIG. 3, the three moving electrodes 4 are arranged along a cross-sectional direction of the gas passage (dust collection zone 12) . The brush units 15 and the lower wheels 17 of each of the moving electrodes 4 are disposed in the dust non-collection zone 13 with the chains 10 turning in the direction shown by vertical arrows and the pair of the brush units 15 turning in the directions shown by the circumferential arrows, respectively, so as to brush off the dust collected by the dust collecting electrode plates 9.
When a moving electrode type electric dust collector constructed as described above is operated for a certain period, moving parts of the moving electrodes 4 are worn and require to be replaced. To be concrete, such constituent parts of the moving electrodes 4 as the dust collecting electrode plates 9, chains 10, upper wheels 16, lower wheels 17, and rotary brushes 15 are replaced when required according to a prescribed replacement criterion. Generally, when replacing a part of an electric dust collector, a required replacement part is first carried into an upper chamber 18. FIG. 6 illustrates an example case of carrying in a replacement part. A replacement part 19 is lifted above the dust collector 1 by a crane 20 and is carried into the upper chamber 18. Workers walk in the upper chamber 18 via a corridor 21 and carry out replacement work from above the dust collector.

The patent document 1 discloses a method of assembling an electric dust collector using a crane. In the method, moving electrodes to form a loop are lifted by a crane, carried in through an upper opening of the casing of the dust collector, and assembled by workers positioned in upper and lower portions of the casing. The patent document 2 discloses a method of replacing a chain for moving electrodes. In the method, a chain to be replaced is cut off, one end of a chain to replace is linked to a cut-off end of the chain to be replaced, and the two chains thus connected are turned so as to sequentially move the dust collecting electrode plates connected to the chain to be replaced to the chain to replace. [Patent Document 1] Japanese Patent Laid-Open No. 2000-342994 [Patent Document 2] Japanese Patent Laid-Open No. 2000-342995
SUMMARY OF THE INVENTION
A general electric dust collector is, however, about 30 m high. Therefore, replacing parts of an electric dust collector by the above described method or carrying out the electric dust collector assembly method disclosed by the patent document 1 requires a large crane for lifting parts of the electric dust collector. This increases the cost of the replacement or assembly work. Furthermore, workers to carry out replacement work are required to walk into a top portion of the electric dust collector using, for example, a corridor. This may make the working conditions severe for the workers. The casing of the electric dust collector

has an opening for carrying in replacement parts. Considering the strength of the casing and the operability in opening/closing the opening, the opening cannot be made arbitrarily large. When the opening is much smaller than required, parts cannot be efficiently carried into the casing and it may also become necessary to reorient the parts carried into the casing resulting in lowering the efficiency of the replacement work. The patent document 2 gives no clear consideration to the opening for carrying parts into the casing.
An object of the present invention that has been made in view of the above problems is to provide a moving electrode type electric dust collector and a method of carrying in parts of the electric dust collector which enable replacement parts to be carried in easily and reduce the work load on the workers to engage in replacement work.
To solve the above problems, the present invention provides a moving electrode type electric dust collector having a casing which causes a dust containing gas to flow from a gas inlet to a gas outlet thereof; multiple discharge electrodes hung in a gas passage which forms a dust collection zone in the casing; and multiple moving electrodes which each include a plurality of dust collecting electrode plates hung from a pair of endless chains, the plurality of dust collecting electrode plates forming a loop and turning around the discharge electrodes, and a brushing unit for brushing the tuning dust collecting electrode plates at a

prescribed position. The moving electrode type electric dust collector comprises: a carry-in stage which is provided outside the casing and downward of the moving electrodes and on which a constituent part of the moving electrodes is tentatively placed; and a carry-in manhole which is provided in a wall near the carry-in stage of the casing and through which the constituent part of the moving electrodes is moved from the carry-in stage into the casing.
In the moving electrode type electric dust collector, according to another aspect of the invention, the carry-in manhole allows the constituent part of the moving electrodes to be moved therethrough from the carry-in stage into the casing, the constituent part being oriented identically to an orientation thereof in an installed state.
In the moving electrode type electric dust collector, according to still another aspect of the invention: the moving electrodes are arranged along a cross-sectional direction of the gas passage to range through a dust collection zone and a dust non-collection zone in the casing; and the carry-in stage and the carry-in manhole are included in a portion of the casing, the portion of the casing being for a portion of the dust non-collection zone near the moving electrodes.
In the moving electrode type electric dust collector, according to still another aspect of the invention: the dust collecting electrode plates are hung from the endless chains such that a width direction of the dust collecting electrode plates in

an installed state extends along the gas passage; and the dust collecting electrode plates are, when required to be carried into the casing, moved along the width direction through the carry-in manhole into the casing.
In the moving electrode type electric dust collector, according to still another aspect of the invention: the dust collecting electrode plates in an installed state are hung from the endless chains such that a width direction of the dust collecting electrode plates extends along the gas passage and the brushing unit is disposed such that a longitudinal direction thereof extends along the width direction of the dust collecting electrode plates; and, when being carried into the casing, the brushing unit is moved through the carry-in manhole along the longitudinal direction.
In the moving electrode type electric dust collector, according to still another aspect of the invention: corresponding to the moving electrodes, a plurality of the carry-in stages and a plurality of the carry-in manholes are provided in the casing.
The present invention also provides a method of carrying a part into a moving electrode type electric dust collector, the electric dust collector having a casing which causes a dust containing gas to flow from a gas inlet to a gas outlet thereof; multiple discharge electrodes hung in a gas passage which forms a dust collection zone in the casing; and multiple moving electrodes which each include a plurality of dust collecting electrode plates hung from a pair of endless chains, the plurality of dust collecting

electrode plates forming a loop and turning around the discharge electrodes, and a brushing unit for brushing the tuning dust collecting electrode plates at a prescribed position. The method of carrying a part into a moving electrode type electric dust collector comprises: tentatively placing a constituent part of the moving electrodes on a carry-in stage which is provided outside the casing and downward of the moving electrodes; and moving the constituent part of the moving electrodes into the casing through a carry-in manhole provided in a wall near the carry-in stage of the casing, the constituent part being oriented identically to an orientation thereof in an installed state.
In the method of carrying a part into a moving electrode type electric dust collector, according to another aspect of the invention; the moving electrodes are arranged along a cross-sectional direction of the gas passage to range through a dust collection zone and a dust non-collection zone in the casing, and the part is carried into the dust non-collection zone for the moving electrodes through the carry-in manhole.
According to the present invention, no large crane is required to carry in parts of a moving electrode type electric dust collector, and it is possible to improve the efficiency of carrying in parts of the dust collector through an opening provided in the casing of the dust collector, the efficiency of moving and installing the parts that have been carried in, and the work environment for workers.

BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 outlines a construction of a moving electrode type electric dust collector;
FIG. 2 is an enlarged view of a moving electrode of a moving electrode type electric dust collector;
FIG. 3 is a partial sectional view taken along line A—A in the direction of the arrows shown in FIG. 2;
FIG. 4 is an enlarged view of an essential part of construction of an embodiment of the present invention;
FIG. 5 illustrates how a replacement part is carried in according to the embodiment of the invention;
FIG. 6 illustrates how a replacement part is carried in for a conventional moving electrode type electric dust collector;
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 3, 4, and 5 show a construction of an embodiment of the present invention. In these drawings, parts which are the same as those shown in the foregoing drawings are denoted by the same reference numerals as in the foregoing drawings.
Referring to FIG. 4, reference numeral 2c denotes a vertical wall, near a lower portion of moving electrodes 4, of a casing 2. The vertical wall 2c makes up a casing portion extending in a direction vertically crossing a horizontal gas flow (gas passage) . It is formed to extend downward vertically from an inclined wall

portion of the casing 2 toward a hopper 6. Reference numeral 22 denotes a carry-in stage projecting horizontally from a lower end portion of the vertical wall 2c (an upper end portion of a hopper 6) provided near a lower end portion of the moving electrodes 4. When a large part, for example, a dust collecting electrode plate 9, a rotary brush (means of brushing dust off) 15, and a chain 10 is carried in as a replacement part, it can be tentatively placed on the carry-in stage 22. Referring to FIG. 4, for example, a rotary brush is placed on the carry-in stage 22 as shown by reference numeral 15a.
Reference numeral 23 denotes a carry-in manhole which is provided in the vertical wall 2c to be in the vicinity of the carry-in stage 22. When the dust collector is operated, the carry-in manhole 23 is closed with a lid (not shown) to prevent the gas in the casing from leaking out.
When moving a replacement part placed on the carry-in stage 22 into the casing 2, the lid of the carry-in manhole 23 is opened allowing the replacement part, oriented identically to its orientation in an installed state, to be moved from the carry-in stage 22 into the casing 2. For example, when the rotary brush 15 is in use, it is oriented, as shown in FIG. 4, such that its rotary axis (longitudinal direction) extends horizontally (sideways) along the direction of the gas flow (direction of the gas passage) . To move the rotary brush 15a placed on the carry-in stage 22 into the casing 2, it is moved horizontally along the direction of its

rotary axis (along its longitudinal direction) as shown by arrows in FIG. 4 (leftward as seen in FIG. 4) , i.e. in the same orientation as it is in when installed for use, through the carry-in manhole 23 as shown by reference numeral 15b. The rotary brush moved into the casing 2 is lifted, without changing its orientation, from the position shown by reference numeral 15b to an installable position shown by reference numeral 15 and installed there. As shown in FIG. 4, the rotary brush 15 is installed such that its axial direction extends along the widths of the dust collecting electrode plates 9.
The width of each of the dust collecting electrode plates 9 in an installed state extends horizontally (sideways) along the gas flow direction (gas passage direction) . When it is carried in, it is moved through the carry-in manhole 23 along its width direction
(horizontally), positioned for installation without changing its orientation, and then attached to the chains 10 (not illustrated) . As described above, with the carry-in manhole 23 provided to allow a part to be carried in therethrough sideways
(horizontally) , parts of the moving electrode 4 can be moved through the carry-in manhole 23 in the same orientation as they are in when they are in an installed state. Therefore, when they are moved into the casing 2, they can be installed in their respective positions without having their orientation changed. This improves the efficiency of part movement and other operations performed in the casing 2 while also reducing the space requirement inside the casing

2.
Referring to FIGS. 3 and 4, the plural moving electrodes 4 are arranged to range through a dust collection zone 12 and a dust non-collection zone 13 in the casing 2 and extend along the cross-sectional direction of the gas passage. The carry-in stage 22 and the carry-in manhole 23 are provided in the vertical wall 2c of the casing 2 for the dust non-collection zone 13 near the moving electrodes 4. The dust non-collection zone 13 in the casing 2 is where the dust collected by the dust collecting electrode plates 9 is brushed off by the rotary brushes 15. There are no discharge electrodes 5 provided in the dust non-collection zone, so that the zone can be suitably used for part replacement. Namely, in the dust non-collection zone, the moving electrodes 4 can be attached to the chains 10 and the rotary brushes 15 can be fixed in their respective positions with high efficiency.
The carry-in stage 22 and a hopper grating 8 provide stable footholds for workers to carry out replacement work, so that the load on the workers can be reduced.
FIG. 5 illustrates how a replacement part is carried in according to the present embodiment. A replacement part 19 is lifted to the carry-in stage 22 using a crane 20 and tentatively placed on the carry-in stage 22. The replacement part 19 is then moved into the casing 2 of the electric dust collector 1 through the carry-in manhole 23. Replacement parts such as the dust collecting electrode plates 9 and rotary brushes 15 can be moved into the casing

2 through the carry-in manhole 23 while they are oriented identically to their orientation in an installed state. That is, the dust collecting electrode plates 9 are moved in along their width direction and the rotary brushes 15 are moved in along their axial direction (longitudinal direction), so that it is not necessary to change their orientation inside the casing 2.
In cases where stationary brushes (not shown) are used instead of the rotary brushes 15 as means of brushing dust off, too, the above advantageous effects of the present invention can be obtained. Namely, the stationary brushes can be moved into the casing 2 along their longitudinal direction, i.e. with the stationary brushes oriented identically to their orientation in an installed state, so that they need not be reoriented inside the casing 2.
Workers to carry out replacement work can move via a corridor 21 to a manhole 24 provided in a side near the lower end of the casing 2.
The electric dust collector 1 is about 30 m high as mentioned in the foregoing. The carry-in stage 22, the carry-in manhole 23 for use in carrying in replacement parts, and the walk-through manhole 24, that is the lowermost manhole, for use by workers are as high as the hoppers 6, i.e. about 15 m high. The crane 20 for lifting replacement parts, therefore, need not be a large machine, so that the work cost can be held low. Furthermore, the workers to engage in replacement work can use the corridor 21 to move to the carry-in stage 22, the carry-in manhole 23, and the lowermost

walk-through manhole 24. This improves the condition under which the replacement work is carried out. Thus, providing the carry-in stage 22 and the carry-in manhole 23 in an upright (vertical) casing portion extending perpendicularly to the horizontal gas flow can reduce the work load in moving in replacement parts and carrying out replacement work.
A plurality of the carry-in manholes 23 are provided corresponding to the plural moving electrodes. As shown in FIG. 3, the plural moving electrodes 4 are arranged along a cross-sectional direction of the gas passage to extend through the dust collection zone 12 and the dust non-collection zone 13 in the casing 2. A carry-in manhole 23 is provided for each of the moving electrodes 4. It is provided in an area indicated, in FIG. 3, by a broken-line box of the vertical wall 2c of the casing portion corresponding to the dust non-collection zone 13 for each of the moving electrodes 4. In this case, there may be either plural carry-in stages 22 corresponding to the plural manholes 23 or a carry-in stage 22 for common use. This construction allows parts replacement work to be carried out efficiently for any of the moving electrodes 4 and provides better environment for parts replacement work.

What Is Claimed Is:
1. A moving electrode type electric dust collector having
a casing which causes a dust containing gas to flow from a gas inlet
to a gas outlet thereof; multiple discharge electrodes hung in a
gas passage which forms a dust collection zone in the casing; and
multiple moving electrodes which each include a plurality of dust
collecting electrode plates hung from a pair of endless chains,
the plurality of dust collecting electrode plates forming a loop
and turning around the discharge electrodes, and a brushing unit
for brushing the tuning dust collecting electrode plates at a
prescribed position; the electric dust collector comprising:
a carry-in stage which is provided outside the casing and downward of the moving electrodes and on which a constituent part of the moving electrodes is tentatively placed; and
a carry-in manhole which is provided in a wall near the carry-in stage of the casing and through which the constituent part of the moving electrodes is moved from the carry-in stage into the casing.
2. The moving electrode type electric dust collector
according to claim 1;
wherein the carry-in manhole allows the constituent part of the moving electrodes to be moved therethrough from the carry-in stage into the casing, the constituent part being oriented

identically to an orientation thereof in an installed state.
3. The moving electrode type electric dust collector according to any one of claims 1 and 2 : wherein the moving electrodes are arranged along a cross-sectional direction of the gas passage to range through a dust collection zone and a dust non-collection zone in the casing; and wherein the carry-in stage and the carry-in manhole are included in a portion of the casing, the portion of the casing being for a portion of the dust non-collection zone near the moving electrodes.
4. The moving electrode type electric dust collector according to any one of claims 1 to 3: wherein the dust collecting electrode plates are hung from the endless chains such that a width direction of the dust collecting electrode plates in an installed state extends along the gas passage; and wherein the dust collecting electrode plates are, when required to be carried into the casing, moved along the width direction through the carry-in manhole into the casing.
5. The moving electrode type electric dust collector according to any one of claims 1 to 4 : wherein the dust collecting electrode plates in an installed state are hung from the endless chains such that a width direction of the dust collecting electrode plates extends along the gas passage and the brushing unit is

disposed such that a longitudinal direction thereof extends along the width direction of the dust collecting electrode plates; and wherein, when being carried into the casing, the brushing unit is moved through the carry-in manhole along the longitudinal direction.
6. The moving electrode type electric dust collector according to any one of claims 1 to 5: wherein, corresponding to the moving electrodes, a plurality of the carry-in stages and a plurality of the carry-in manholes are provided in the casing.
7. A method of carrying a part into a moving electrode type electric dust collector, the electric dust collector having a casing which causes a dust containing gas to flow from a gas inlet to a gas outlet thereof; multiple discharge electrodes hung in a gas passage which forms a dust collection zone in the casing; and multiple moving electrodes which each include a plurality of dust collecting electrode plates hung from a pair of endless chains, the plurality of dust collecting electrode plates forming a loop and turning around the discharge electrodes, and a brushing unit for brushing the tuning dust collecting electrode plates at a prescribed position; the method comprising:
tentatively placing a constituent part of the moving electrodes on a carry-in stage which is provided outside the casing and downward of the moving electrodes; and

moving the constituent part of the moving electrodes into the casing through a carry-in manhole provided in a wall near the carry-in stage of the casing, the constituent part being oriented identically to an orientation thereof in an installed state.
8 . The method of carrying a part into a moving electrode type electric dust collector according to claim 7; wherein the moving electrodes are arranged along a cross-sectional direction of the gas passage to range through a dust collection zone and a dust non-collection zone in the casing, and the part is carried into the dust non-collection zone for the moving electrodes through the carry-in manhole.
9. The method of carrying a part into a moving electrode type
electric dust collector according to any one of claims 7 and 8:
wherein the dust collecting electrode plates are hung from the
endless chains such that a width direction of the dust collecting
electrode plates in an installed state extends along the gas
passage; and wherein the dust collecting electrode plates are, when
required to be carried into the casing, moved along the width
direction through the carry-in manhole into the casing.
10. The method of carrying a part into a moving electrode
type electric dust collector according to any one of claims 7 to
9: wherein the dust collecting electrode plates are hung from the

endless chains such that a width direction of the dust collecting electrode plates in an installed state extends along the gas passage, and the brushing unit is disposed such that a longitudinal direction thereof extends along the width direction of the dust collecting electrode plates; and wherein, when required to be carried into the casing, the brushing unit is moved through the carry-in manhole along the longitudinal direction into the casing.