ELECTROSTATIC PRECIPITATOR AND SWEEPING APPARATUS BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to an electrostatic precipitator and a sweeping apparatus having movable electrodes, and particularly, to an electrostatic precipitator and a sweeping apparatus having a plurality of discharge electrodes suspended at predetermined intervals in a casing and a plurality of dust-collecting plates which are rotated while being arranged near the discharge electrodes.
(2) Description of the Related Art
The electrostatic precipitator of this kind is known as an electrostatic precipitator for removing dust contained in an exhaust gas from, for example, a boiler of a thermal power plant or various types of iron manufacturing furnaces, and an outline structure shown in Japanese Patent Application Laid-Open No. 2001-246286 will be described on the basis of Fig. 9 to Fig. 13.
In Fig. 9, a movable electrode-type electrostatic precipitator 10 includes a casing 12, a hopper 13 located at a lower part of the casing 12, and a plurality of discharge frames (discharge electrodes) 14 and a plurality of movable electrodes 15 arranged in the casing 12. The dust contained in an exhaust gas 17 introduced within the casing 12 from an inlet flue 16 is removed in accordance with the principle of electrostatic precipitation, and the gas is discharged from an outlet flue 18. The collected dust drops within the hopper 13, and is taken out of an exhaust port 20 by a mechanism (not shown).
Fig. 10 is a diagram taken along the arrow line A-A of Fig. 9, and
a plurality of discharge frames 14 provided at predetermined intervals are suspended through a suspension frame 24 suspended from an insulator 22 shown in Fig. 9 in the casing 12. In addition, a plurality of movable electrodes 15 which are rotated around every other discharge frame 14 are arranged.
Fig. 11 is a perspective view showing a structure of the movable electrode 15, and a pair of endless chains 30 and 30 are provided between upper driving wheels 26 and lower rollers 28. A plurality of dust-collecting plates 32 are suspended by the pair of endless chains 30 and 30 while each plate is locked at the position of a middle portion 33 in the vertical length of the moving direction, and plate surfaces are arranged along the flow of the gas to form a loop as a whole. A driving shaft 34 of the driving wheels 26 is rotated by a driving mechanism (not shown) , the rotation of the driving shaft 34 is transmitted to the pair of endless chains 30 and 30 which mesh with the driving wheels 26, and a plurality of dust-collecting plates 32 forming the loop are rotated around every other discharge frame 14.
Fig. 12 is an arrangement diagram of lower parts of the movable electrodes 15. Each of the dust-collecting plates 32 which are suspended by the endless chain 30 and move downward makes a U-turn at the position of the lower roller 28, and moves upward. A pair of rotational brushes 36 and 38 (hereinafter, the pair of rotational brushes are collectively referred to as a brush unit that is represented by the reference numeral 40) are arranged for each lane of the movable electrodes 15 at the position
where the dust-collecting plate 32 immediately after moving upward is
sandwiched. The brushes 36 and 38 are formed by implanting a metal brush into a rotational shaft. The brush 36 is rotated in the clockwise direction whereas the brush 38 is rotated in the counterclockwise direction, so that the dust adhere to surfaces of the dust-collecting plate 32 is swept and dropped downward. The dust-collecting plate 32 whose dust adhere to the surface was removed by the brush unit 40 sequentially moves upward, the discharge frames 14 collect the dust contained in the exhaust gas on their surfaces at a certain discharge region in accordance with the principle of electrostatic precipitation, and the dust-collecting plate 32 moves downward again.
The number of lanes for the movable electrodes 15 in a large-scale apparatus reaches to as many as 50 to 100. Thus, a driving apparatus for driving these electrodes and a driving apparatus for rotationally driving the brush units 40 are needed, which results in the increased cost of the apparatus. In addition, if the brush unit is worn, it is difficult to change the pressing range of the brush unit due to the presence of a driving unit, which leads to the necessity of cost and time for exchanging the brush unit in order to secure its function.
Japanese Patent Application Laid-Open No. 2003-62486 shows an electrostatic precipitator using a fixed brush. In this technique, the fixed brush is pressed to and brought into contact with a metal net of dust-collecting electrodes by its own weight or a spindle to sweep the dust.
However, if the fixed brush described in Japanese Patent
Application Laid-open No. 2003-62486 is employed in the electrostatic
precipitator described in Japanese Patent Application Laid-open No. 2001-246286, the fixed brush enters a clearance between the adjacent dust-collecting plates of Japanese Patent Application Laid-Open No. 2001-246286 to increase the driving resistance of the rotational movement of the dust-collecting plates. In addition, in the case of the brushes arranged to face the both surfaces of each dust-collecting plate, the hairs of the brushes entering the clearance become tangled to possibly stop the rotational movement.
Further, in the configuration where the fixed brush is pressed to the dust-collecting electrodes by its own weight, when the brush is worn, the brush leans against the dust-collecting electrodes, and the contact angle is accordingly changed. Thus, it is difficult to accurately recognize a dust sweeping amount due to instability of the detachability of dust. Further, in order to secure a pressing force with the weight of the brush or the spindle, the brush is used in an inclined manner from the beginning, and is largely inclined to the dust-collecting electrodes when the brush is worn in use. Accordingly, it is difficult to secure a large pressing range (a moving range to the dust-collecting electrodes) , and to maintain a uniform sweeping performance for a long term.
Further, the number of lanes for the movable electrodes in a large-scale apparatus reaches to as many as 50 to 100 in Japanese Patent Application Laid-Open No. 2001-246286. Thus, a driving apparatus for driving these electrodes and a driving apparatus for rotationally driving the brush units 40 are needed, which results in the increased cost of
the apparatus. In addition, if the brush unit is worn, it is difficult
to change the pressing range of the brush unit due to the presence of a driving unit, which leads to the necessity of cost and time for exchanging the brush unit in order to secure its function.
Further, since the brush in Japanese Patent Application Laid-Open No. 2003-62486 is a fixed brush formed by hair implantation, dust adhere to the dust-collecting plates can not be sufficiently swept in the rotational movement in some cases. Specifically, dust strongly adhere to the dust-collecting plates can not be sufficiently swept by the implanted brush in some cases.
In view of the conventional problems, an object of the present invention is to provide an electrostatic precipitator and a sweeping apparatus by which costs related to sweeping of dust can be reduced, a dust sweeping performance can be improved, and a uniform sweeping performance can be maintained for a long term.
SUMMARY OF THE INVENTION
In order to solve the above-described problems, the present invention provides an electrostatic precipitator including: a casing which allows a dust-containing gas to flow from an inlet for a gas to an outlet; a plurality of discharge electrodes which are suspended in a gas flow channel serving as a dust-collecting area in the casing; and a plurality of movable electrodes which are rotated by forming a loop using a plurality of dust-collecting plates suspended by a pair of endless chains and which include sweeping units for brushing surfaces of the dust-collecting plates being rotated at predetermined positions, wherein
the sweeping unit includes: an elongated brush which extends in the width
direction of the surface of the dust-collecting plate and is brought into contact therewith; a link mechanism to one end of which the brush is attached and the other end of which is fixed to a fixed member; a biasing unit which allows the brush to be pressed to and brought into contact with the dust-collecting plate through the link mechanism; and a restricting unit which restricts the press of the brush so that the brush is prevented from being fitted into a clearance between the adjacent dust-collecting plates.
In order to solve the above-described problems, the present invention provides an electrostatic precipitator including: a casing which allows a dust-containing gas to flow from an inlet for a gas to an outlet; a plurality of discharge electrodes which are suspended in a gas flow channel serving as a dust-collecting area in the casing; and a plurality of movable electrodes which are rotated by forming a loop using a plurality of dust-collecting plates suspended by a pair of endless chains and which include sweeping units for brushing surfaces of the dust-collecting plates being rotated at predetermined positions, wherein the sweeping unit includes: an elongated brush which extends in the width direction of the surface of the dust-collecting plate and is brought into contact therewith; a link mechanism to one end of which the brush is attached and the other end of which is fixed to a fixed member; and a biasing unit which allows the brush to be pressed to and brought into contact with the dust-collecting plate through the link mechanism, and is attached to the link mechanism while being inclined so that the brush
is prevented from being fitted into a clearance between the adjacent
dust-collecting plates and the brush is brought into contact with the
dust-collecting plates across the clearance.
In the electrostatic precipitator according to any one of the above-described aspects, the link mechanism is configured using a parallelogram link, and the brush and the biasing unit are attached to a front end and a rear end of the parallelogram link, respectively.
In the electrostatic precipitator according to any one of the above-described aspects, the biasing unit is a spindle, and the link mechanism is rotated by the gravity of the spindle to press the brush to the dust-collecting plate.
In the electrostatic precipitator according to any one of the above-described aspects, a plurality of brushes are divided and aligned in the width direction of the dust-collecting plate.
In the above-described electrostatic precipitator, the biasing unit is provided for each brush so that each of a plurality of divided and aligned brushes is pressed to and brought into contact with the dust-collecting plate with each biasing force.
The present invention provides a sweeping apparatus which brushes a surface of a target object by moving relative to the target object, the apparatus including: a brush which brushes a surface of the target object; a link mechanism to one end of which the brush is attached and the other end of which is fixed to a fixed member; and a biasing unit which allows the brush to be pressed to and brought into contact with the target object through the link mechanism.
In the above-described sweeping apparatus, a restricting unit for
restricting the press of the brush to the target object is further provided. Further, in the above-described sweeping apparatus, the link mechanism is configured using a parallelogram link, and the brush and the biasing unit are attached to a front end and a rear end of the parallelogram link, respectively. Furthermore, in the above-described sweeping apparatus, the biasing unit is a spindle, and the link mechanism is rotated by the gravity of the spindle to press the brush to the target object. Furthermore, in the above-described sweeping apparatus, a plurality of brushes are divided and aligned in the width direction of the target object. Furthermore, in the above-described sweeping apparatus, the biasing unit is provided for each brush so that each of a plurality of divided and aligned brushes is pressed to and brought into contact with the target object with each biasing force.
In order to solve the above-described problems, the present invention provides an electrostatic precipitator including: a casing which allows a dust-containing gas to flow from an inlet for a gas to an outlet; a plurality of discharge electrodes which are suspended in a gas flow channel serving as a dust-collecting area in the casing; and movable electrodes which are rotated by forming a loop using a plurality of dust-collecting plates suspended by a pair of endless chains and which include sweeping units for brushing surfaces of the dust-collecting plates being rotated at predetermined positions, wherein the sweeping unit includes brushes which are formed in an elongated shape extending in the width direction of the dust-collecting plate and which are aligned
and arranged at plural stages in the rotational direction, and biasing
units which allow the brushes to be pressed to and brought into contact with the dust-collecting plate, and the dust-collecting plates are brushed by the brushes at the respective stages with the rotational movement of the dust-collecting plates.
In the above-described electrostatic precipitator, the brush at the upstream stage (stage where brushing is performed for the first time) in the rotational direction of the dust-collecting plates is strong in hardness, and the brush at the downstream stage is weak in hardness.
In the above-described electrostatic precipitator, the brush at the upstream stage (stage where brushing is performed for the first time) in the rotational direction of the dust-collecting plates is a plate-like brush, and the brush at the downstream stage is a brush formed of a plurality of hairs.
In the above-described electrostatic precipitator, the brushes at the respective stages are attached while being inclined so that the brushes are prevented from being fitted into a clearance between the adjacent dust-collecting plates and are brought into contact with the dust-collecting plates across the clearance.
In the above-described electrostatic precipitator, the biasing unit includes a restricting unit which restricts the press of the brushes to the dust-collecting plate so that the brushes are prevented from being fitted into the clearance between the adjacent dust-collecting plates.
In the above-described electrostatic precipitator, a plurality of brushes at the respective stages are divided and aligned in the width
direction of the dust-collecting plate.
In the above-described electrostatic precipitator, the brushes at plural stages aligned in the rotational direction of the dust-collecting plates are arranged in the width direction of the dust-collecting plate while being divided into a plurality of sets.
In the above-described electrostatic precipitator, the biasing unit is provided for each set so that each set of brushes is pressed to and brought into contact with the dust-collecting plate with each biasing force.
The present invention provides a sweeping apparatus which brushes a surface of a target object by moving relative to the target object, the apparatus including: brushes which brush the surface of the target object and are aligned and arranged at plural stages in the relatively moving direction; and biasing units which allow the brushes to be pressed to and brought into contact with the target object, wherein the target obj ect is brushed by the brushes at the respective stages with the relative movement.
In the above-described sweeping apparatus, the brushes at plural stages are different in hardness, and the brush at the stage where the target object is brushed for the first time is stronger in hardness. Further, in the above-described sweeping apparatus, the brush at the stage where the target object is brushed for the first time is the plate-like brush, and the brushes at the other stages are brushes formed of a plurality of hairs.
In order to solve the above-described problems, the present
invention provides an electrostatic precipitator including: a casing which allows a dust-containing gas to flow from an inlet for a gas to an outlet; a plurality of discharge electrodes which are suspended in a gas flow channel serving as a dust-collecting area in the casing; and a plurality of movable electrodes which are rotated by forming a loop using a plurality of dust-collecting plates suspended by a pair of endless chains and which include sweeping units for brushing surfaces of the dust-collecting plates being rotated at predetermined positions, wherein the sweeping unit includes: an elongated brush which extends in the width direction of the surface of the dust-collecting plate and is brought into contact therewith.
According to said electrostatic precipitator, the dust swept and dropped downward flows to rearward with the exhaust gas flow, and the elongated brush is possible to prevent the dust from raising at a rear part of the elongated brush.
According to the present invention, it is possible to reduce the cost of an electrostatic precipitator with a simple configuration, to improve a dust sweeping performance, and to maintain the dust sweeping performance for a long term. Further, it is possible to reduce the cost of a sweeping apparatus with a simple configuration, to improve a sweeping performance for brushing a surface of a target object, and to maintain the dust sweeping performance for a long term. Furthermore, the brush is possible to prevent the swept dust from raising at a rear part of the brush.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is an arrangement diagram of lower parts of movable
electrodes according to a first embodiment of the present invention;
Fig. 2 is a detailed diagram of a brush unit according to the first embodiment;
Fig. 3 is a perspective view of the brush unit according to a second embodiment;
Fig. 4 is a perspective view of the brush unit according to a third embodiment;
Fig. 5 is a perspective view of the brush unit according to a fourth embodiment;
Fig. 6 is a detailed view of the brush unit according to a fifth embodiment;
Fig. 7 is a perspective view of the brush unit according to a sixth embodiment;
Fig. 8 is a perspective view of the brush unit according to a seventh embodiment;
Fig. 9 is a side sectional view for showing a general configuration of an electrostatic precipitator;
Fig. 10 is a view taken along the arrow line A-A of Fig. 10;
Fig. 11 is a perspective view for showing a general configuration of a movable electrode;
Fig. 12 is an arrangement diagram of lower parts of general movable electrodes; and
Fig. 13 is a graph for showing a relation between an angle of a brush and a dust sweeping amount.
DETAILED DESCRIPTION OF THE EMBODIMENT
Fig. 1 is an arrangement diagram of lower parts according to a first embodiment of the present invention. The entire configuration of an electrostatic precipitator is the same as that shown in Fig. 9 to Fig. 13 explained in the section of the background art, and units which are given the same reference numerals as those in the background art show the same constituent elements.
Movable electrodes 15A, 15B, and 15C arranged in parallel in Fig. 1 are suspended by endless chains 30, and each of dust-collecting plates 32A, 32B, and 32C which move downward in the course of rotation makes a U-turn at the position of a lower roller 28 and moves upward. Sweeping units (brush units) 40A, 40B, and 40C are arranged at positions where both surfaces of each of the dust-collecting plates 32A, 32B, and 32C immediately after moving upward are sandwiched, respectively.
The brush unit 40A includes a pair of elongated brushes 1 and 2 which are brought into contact with surfaces of each dust-collecting plate and extend in the width direction thereof, parallelogram links 3 and 4, as link mechanisms, which support the brushes at their front ends, and biasing units (spindles) 5 and 6 which are fixed to rear ends of the links. The biasing units press the pair of brushes 1 and 2 in the arrow directions where the dust-collecting plate 32A is sandwiched, and dust adhere to the both surfaces of the dust-collecting plate 32A is swept. The configuration of the brush unit 40A is the same as those of the brush units 40B and 40C.
In Fig. 2, a part of the brush unit 40A as an example is shown in
detail. In order to arrange an upper side 4a and a lower side 4b, which
are in parallel with each other, orthogonal to the dust-collecting plate 32A in the parallelogram link 4, a rear end of the lower side 4b is fixed to a fixed beam (fixed member) 7 of the electrostatic precipitator, and the elongated brush 2 is fixed to a front end of the upper side 4a towards the dust-collecting plate 32A. A front side 4c and a rear side 4d are rotatably linked to the both sides 4a and 4b, the rear side 4d extends downward while being bent from a link supporting point 4e of the rear side 4d with the side 4b, and the spindle (biasing unit) 6 is attached to a lower end thereof.
The spindle 6 is driven by the gravity (indicated by the arrow) so that the upper side 4a of the parallelogram link 4 is moved in the arrow direction. Accordingly, the brush 2 fixed to the upper side 4a is biased in the arrow direction through the parallelogram link 4, and is pressed to and brought into contact with the dust-collecting plate 32A. The pressing force is adjusted with the weight of the spindle so that a pressure suitable for sweeping the dust adhere to the dust-collecting plate 32A with the brush 2 can be obtained.
The brush 2 is a metal brush formed by bundling wire-like metal hairs, and is fixed to the side 4a, so that the brush 2 is brought into contact with the dust-collecting plate 32A while being inclined in the travelling direction (upper direction) of the dust-collecting plate 32A by an angle a (0° to 45°) relative to a line orthogonal to the surface of the dust-collecting plate 32A. The inclined angle a of the brush 2 is set to enhance the dust sweeping efficiency. Further, even if the
brush 2 is worn, the brush 2 is moved in parallel towards the direction
of the dust-collecting plate 32A through the parallelogram link 4 as a link mechanism, and the constant angle a is maintained.
Fig. 13 shows a graph of a relation between the angle a and a dust sweeping amount. The vertical axis represents a level (relative value) of a dust remaining amount (thickness of remaining dust) after sweeping, the horizontal axis represents the number of times of sweeping, and the angle a is set at 0°, 45°, and 60°. It can be understood from this graph that the remaining amount after sweeping is small at angles of 0° and 45° whereas the remaining amount is large at an angle of 60°. Specifically, if the angle a is set at 0° to 45°, it is possible to efficiently sweep the dust. This is possibly derived from the reason that as the angle a becomes smaller, the number of hairs of the brush which is brought into contact with the dust-collecting plate becomes larger.
Further, by adjusting the rising angles of the front side 4c and the rear side 4d of the parallelogram link 4, the moving range of the brush 2 towards the dust-collecting plate 32A can be arbitrarily set. Specifically, the both sides 4c and 4d are inclined on the left side in Fig. 2. However, if the both sides are orthogonally arranged at the beginning of use, the moving range from the orthogonal positions towards the dust-collecting plate 32A can be largely secured. If the brush is worn when being used, its sweeping performance can be maintained for a long term.
Thus, according to the embodiment, the brush 2 is pressed to the surface of the dust-collecting plate 32A at a constant angle for a long
term to sweep the dust, so that a constant dust sweeping amount can be
maintained for a long term from the beginning of use.
As illustrated in Fig. 1 and Fig. 2, the movable electrodes 15 are configured in such a manner that a plurality of dust-collecting plates (32A, 32B, and 32C) are suspended by the endless chains 30. In order for the dust-collecting plates to easily move when each one makes a U-turn at the position of the lower roller 28 in the course of rotation, a clearance 31 with a predetermined width is provided between the adjacent dust-collecting plates 32A. As described above, the brush 2 is always pressed to and brought into contact with the dust-collecting plate 32A by the gravity of the spindle 6, and thus, tip ends of the hairs enter the clearance 31 (interval W) .
If the tip ends of the hairs shallowly enter the clearance 31, no problem arises. However, if the tip ends of the hairs deeply enter, the driving resistance of the rotational movement of the dust-collecting plates is increased. In addition, in the case where the brushes are arranged so as to face the both surfaces of each of the dust-collecting plates as shown in Fig. 1, the hairs of the brushes entering the clearance 31 from the both sides become tangled, and the rotational movement is possibly stopped.
The reference numeral 8 denotes a stopper (restricting unit) for restricting the moving range of the spindle 6 so that the hairs of the brush do not deeply enter the clearance between the dust-collecting plates. The spindle 6 is moved in the arrow direction of Fig. 2 by rotation about the supporting point 4e of the rear side 4c of the parallelogram, and
the stopper 8 is fixed to the fixed member 7 so as to restrict the movement.
Accordingly, the spindle 6 allows the brush 2 to be always pressed to the surface of the dust-collecting plate 32A by the gravity. However, if the tip ends of the hairs slightly enter the clearance 31 when the brush 2 passes through the clearance 31, the spindle 6 is moved in the arrow direction of Fig. 2 to cause a lower end thereof to abut on the stopper 8. Thus, further movement is restricted, and the movement of the brush 2 is accordingly restricted. Therefore, it is possible to prevent the tip ends of the hairs of the brush 2 from deeply entering the clearance 31.
Fig. 3 shows a perspective view of a main part according to a second embodiment of the present invention. In the second embodiment, the elongated brush 2 is attached to the link mechanism while being inclined in the rotational direction of the dust-collecting plates, so that the brush 2 is brought into contact with the surfaces of the dust-collecting plates across the clearance 31 (height W) between the adjacent dust-collecting plates (the brush 2 intersects with the clearance 31 to be brought into contact with the surfaces of the dust-collecting plates) . Such a configuration prevents the tip ends of the hairs of the elongated brush 2 from deeply entering the clearance 31 because a part of the elongated brush 2 is always brought into contact with the surfaces of the dust-collecting plates. Specifically, the elongated brush 2 is allowed to be brought into contact with the surfaces of the dust-collecting plates across the clearance 31, so that the dust-collecting plates are used as stoppers. The inclined angle of the
the stopper 8 is fixed to the fixed member 7 so as to restrict the movement.
Accordingly, the spindle 6 allows the brush 2 to be always pressed to the surface of the dust-collecting plate 32A by the gravity. However, if the tip ends of the hairs slightly enter the clearance 31 when the brush 2 passes through the clearance 31, the spindle 6 is moved in the arrow direction of Fig. 2 to cause a lower end thereof to abut on the stopper 8. Thus, further movement is restricted, and the movement of the brush 2 is accordingly restricted. Therefore, it is possible to prevent the tip ends of the hairs of the brush 2 from deeply entering the clearance 31.
Fig. 3 shows a perspective view of a main part according to a second embodiment of the present invention. In the second embodiment, the elongated brush 2 is attached to the link mechanism while being inclined in the rotational direction of the dust-collecting plates, so that the brush 2 is brought into contact with the surfaces of the dust-collecting plates across the clearance 31 (height W) between the adjacent dust-collecting plates (the brush 2 intersects with the clearance 31 to be brought into contact with the surfaces of the dust-collecting plates) . Such a configuration prevents the tip ends of the hairs of the elongated brush 2 from deeply entering the clearance 31 because a part of the elongated brush 2 is always brought into contact with the surfaces of the dust-collecting plates. Specifically, the elongated brush 2 is allowed to be brought into contact with the surfaces of the dust-collecting plates across the clearance 31, so that the dust-collecting plates are used as stoppers. The inclined angle of the
brush 2 in this case is set at 5° to 45° relative to the width (lateral)
direction (longitudinal direction of the clearance 31) of the dust-collecting plate 32.
Fig. 4 shows a perspective view of a main part according to a third embodiment of the present invention. In the third embodiment, two sets of the elongated brushes 2 of the second embodiment are aligned and arranged in the width (lateral) direction of the dust-collecting plate 32 while being inclined in the same direction. The laterally-aligned brushes are arranged so that their sweeping ranges slightly overlap with each other. Two sets of the parallelograms 4 are fixed to the fixed member 7 so that the upper and lower sides 4a and 4b which are in parallel with each other are substantially horizontal, and the brushes 2 are attached to the sides 4a in an inclined manner. The spindles 6 are separately provided at the respective parallelogram links 4, and a pressing force (biasing force) can be separately applied to each set of the brushes.
If the length of each elongated brush 2 becomes too long, there is a possibility that the brush is bent and the pressing force of the both ends of the brush against the dust-collecting plate 32 can not be sufficiently secured. According to the embodiment, by providing a plurality of divided brushes 2, the length of each brush is shortened so that each brush is hardly bent. Accordingly, the pressing force from the upper side 4a can be transmitted to the whole length of the brush, resulting in less irregularities of sweeping.
Further, the plate surface of the dust-collecting plate 32 is arranged along the flow of an exhaust gas of a boiler. Accordingly, one
end of the plate surface in the width direction corresponds to the upstream
side of the gas and the other end thereof corresponds to the downstream side, which possibly causes irregularities in the thickness of the dust along the width direction. The pressing force (biasing force) of each set of the brushes can be separately applied in the embodiment. Accordingly, the spindle located at an area where the thickness of the dust on the dust-collecting plate is large is made heavier than the other to enhance a sweeping force, and thus, it is possible to uniform the dust remaining amount after sweeping.
Fig. 5 shows a perspective view of a main part according to a fourth embodiment of the present invention. In the embodiment, two sets of the elongated brushes 2 are aligned and arranged in the width (lateral) direction of the dust-collecting plate 32 while being inclined in the directions opposed to each other. Two sets of the brushes 2 are inclined in the same direction in the third embodiment of Fig. 4, and thus, the dust-collecting plate 32 tends to be pressed and biased in one of the width direction by the brushes 2 in the course of the rotational movement. In Fig. 4, two sets of the brushes 2 which are inclined in the counterclockwise direction press the dust-collecting plate 32 to the right side of the width direction to possibly result in rotational movement biased on the right side. Since two sets of the brushes 2 are inclined in the directions opposed to each other in the embodiment, the pressing forces of the brushes against the dust-collecting plate are offset, and the above-described problem does not occur. In addition, the brushes 2 are attached while being inclined downward towards the end
portions of the dust-collecting plate 32. Such inclination allows the
dust on the dust-collecting plate 32 to be swept and collected in the both end directions of the dust-collecting plate 32 with the brushes 2, and the collected dust drops. Thus, less dust drops into the parallelograms 4, and the parallelograms 4 are hardly deteriorated.
It should be noted that although the parallelogram link is used as a link mechanism in each embodiment, the present invention is not limited to this, but the brush 2 may be provided at a front end of the side 4c by using, for example, only the sides 4b and 4c in Fig. 2. In addition, although the spindle is used as a biasing unit, a biasing spring may be alternatively used.
Further, as a restricting unit for restricting the movement of the brush, the stopper for restricting the movement of the spindle is used in the embodiments. However, for example, the movement range of the parallelogram link or the brush may be alternatively restricted.
The electrostatic precipitator has been described in each embodiment. However, the present invention can be applied to another target object instead of the dust-collecting plate. The configuration (the reference numerals denote the corresponding parts) thereof is described as follows.
A sweeping apparatus brushes a surface of a target object by moving relative to the target object (32), and includes brushes (1 and 2) along the surface of the target object, a link mechanism (4) to one end of which the brush is attached and the other end of which is fixed to a fixed member, and biasing units (5 and 6) which allow the brushes to be pressed to and
brought into contact with the target object through the link mechanism.
In the above-described sweeping apparatus, a restricting unit (8) for restricting the press of the brush to the target object is further provided.
Further, in the above-described sweeping apparatus, the link mechanism is configured using a parallelogram link (4), and the brush and the biasing unit are attached to a front end and a rear end of the parallelogram link, respectively. Furthermore, in the above-described sweeping apparatus, the biasing unit is a spindle, and the link mechanism is rotated by the gravity of the spindle to press the brush to the target object. Furthermore, in the above-described sweeping apparatus, a plurality of brushes are divided and aligned in the width direction of the target object. Furthermore, in the above-described sweeping apparatus, the biasing unit is provided for each brush so that each of a plurality of divided and aligned brushes is pressed to and brought into contact with the target object with each biasing force. Thus, the same effects as those in the embodiments of the electrostatic precipitator can be obtained with the above-described configuration.
Next, a fifth embodiment of the present invention will be described. The arrangement of the lower parts of the movable electrodes in the fifth embodiment is the same as Fig. 1. Thus, the explanation thereof will not be repeated, but will be made in Fig. 6 and the subsequent drawings. Fig. 6 shows detailed right half portions of the brush units 4 0 shown in Fig. 1. Elongated bushes 2a, 2b, and 2c are configured at three stages along the rotational direction (travelling direction) of the
dust-collecting plates 32 from the downstream side (the upper side in
Fig. 2) towards the upstream side (the lower side in Fig. 2 where brushing is performed for the first time). The related structures of the elongated bushes 2a, 2b, and 2c are the same as those in the first embodiment of Fig. 1, and thus, the explanations thereof will not be repeated.
In Fig. 6, the brushes 2a and 2b are metal brushes formed by bundling wire-like metal hairs, and the brush 2c is a plate-like brush made of metal or synthetic resin. Among the brushes, the plate-like brush 2c is the strongest (highest rigidity) in hardness, the brush 2a is weak (low rigidity) in hardness, and the brush 2b is set at the intermediate level of hardness. By such setting, for the strongly-fixed dust among those adhere to the surfaces of the dust-collecting plates 32, rough sweeping is performed by the plate-like brush 2c at the stage (stage on the upstream side) where brushing is performed for the first time, intermediate finish sweeping is performed by the brush 2b at the stage where brushing is performed for the next time, and final finish sweeping is performed by the brush 2a at the stage (stage on the downstream side) where brushing is finally performed. Accordingly, the sweeping performance similar to that of the conventional rotational brushes can be obtained.
There will be described a relation between the hardness of each brush and sweeping. The plate-like brush that is strong (high rigidity) in hardness is brought into contact with the dust-collecting plate with a high pressure, but is weak in adhesiveness, thus being suitable for
sweeping hard and large dust. The implanted brush that is weak (low
rigidity) in hardness is brought into contact with the dust-collecting plate with a low pressure, but is excellent in adhesiveness, thus being suitable for sweeping fine dust. Accordingly, various types of dust are continuously swept plural times by the brushes at the respective stages that are different from each other in hardness, so that the sweeping performance can be improved. Due to the constant flow of a dust-containing exhaust gas, additional dust is immediately attached to the dust-collecting plates after a while. Thus, as shown in Fig. 6, the rough sweeping is performed by arranging the brush that is strong in hardness on the upstream side, and thereafter, the fine dust remaining after the rough sweeping is swept by the brush that is weak in hardness. Accordingly, a high sweeping performance can be obtained as a whole.
The sweeping performance can be confirmed also in Fig. 13. Fig. 13 is a graph for showing a relation between the angle a and a dust sweeping amount, and is also a graph for showing a relation between the number of times of sweeping and a dust sweeping amount. Each level of the dust remaining amounts (thicknesses of remaining dust) after the second and the third sweeping is reduced as compared to that after the first sweeping. In particular, the remaining amount after the second sweeping is remarkably reduced. In the embodiment, the sweeping is continuously performed three times by the brushes 2a, 2b, and 2c at three stages when the dust-collecting plate 32 passes through.
Fig. 7 shows a perspective view of a main part according to a sixth embodiment of the present invention. In the embodiment, a plurality of
elongated brushes 2a and 2c shown in Fig. 6 are divided and aligned in
the width (lateral) direction of the dust-collecting plate 32 while being inclined in the travelling direction of the dust-collecting plate, and are arranged at two stages. The laterally-aligned brushes are arranged so that the seeping ranges overlap with each other.
As similar to Fig. 6, the respective brushes 2a and 2c are fixed to the parallelogram links 4, the respective parallelogram links 4 are fixed to the fixed members 7a and 7c, and the respective spindles 6a and 6c are attached to lower ends extended downward from the rear sides 4d. In addition, the respective spindles are linked to link shafts 11a and 11d which penetrate through the link supporting points 4e between the rear sides 4d and the lower sides 4b, and the laterally-aligned brushes are pressed to the dust-collecting plate 32 with a uniform and separate pressure at each stage.
According to the sixth embodiment, by providing a plurality of divided and aligned brushes 2a and 2c in the lateral direction, the length of each brush is shortened so that each brush is hardly bent. Accordingly, the pressing force from the upper side 4a can be transmitted to the whole length of the brush, resulting in less irregularities of sweeping. In addition, the brushes can be pressed to the dust-collecting plate with a separate pressure at each stage, so that the dust sweeping amount can be controlled at each stage, and an efficient sweeping performance can be set as a whole.
Fig. 8 shows a perspective view of a main part according to a seventh embodiment of the present invention. In the embodiment, the elongated
brushes 2a, 2b, and 2c at three stages shown in Fig. 6 are inclined in
the travelling direction of the dust-collecting plate 32, and are arranged while being divided into five sets in the width (lateral) direction of the dust-collecting plate 32. The laterally-aligned brushes are arranged so that their sweeping ranges slightly overlap with each other.
As similar to Fig. 7, the respective brushes 2a, 2b, and 2c are fixed to the parallelogram links 4. However, Fig. 8 is different from Fig. 7 in that the brushes at three stages in each set are fixed to one parallelogram link through a link plate 9 (shown by the dashed line). The respective brushes are fixed to each link plate 9 in an inclined manner, each link plate 9 is fixed to the upper side 4a of each parallelogram link 4, and the rear side 4d of each parallelogram link 4 is fixed to one fixed member (fixed beam) 7. In addition, the spindles 6 are separately provided at the parallelogram links 4 in the respective sets, and a pressing force (biasing force) can be separately applied to the brushes in each set.
According to the seventh embodiment, by laterally providing a plurality of divided and aligned brushes, the length of each brush can be shortened as compared to that in the second embodiment, and thus, a pressing force can be sufficiently secured in the whole length of each brush. Further, the plate surface of the dust-collecting plate 32 is arranged along the flow of an exhaust gas of a boiler. Accordingly, one end of the plate surface in the width direction corresponds to the upstream side of the gas and the other end thereof corresponds to the downstream side, which possibly causes irregularities in the thickness of the dust
collected along the width direction. The pressing force (biasing force)
of the brushes in each set can be separately applied in the embodiment. Accordingly, the spindle located at an area where the thickness of the dust on the dust-collecting plate is large is made heavier to enhance a sweeping force, and thus, it is possible to uniform the dust remaining amount after sweeping.
It should be noted that although the parallelogram link is used as a link mechanism in each embodiment, the present invention is not limited to this, but the brush 2 may be provided at a front end of the side 4c by using, for example, only the sides 4b and 4c in Fig. 2. In addition, although the spindle is used as a biasing unit, a biasing spring may be alternatively used.
Further, as a restricting unit for restricting the movement of the brush, the stopper for restricting the movement of the spindle is used in the embodiments. However, for example, the movement range of the parallelogram link or the brush may be alternatively restricted. The electrostatic precipitator has been described in each embodiment. However, the present invention can be applied to another target object instead of the dust-collecting plate. The configuration (the reference numerals denote the corresponding parts) thereof is described as follows.
A sweeping apparatus brushes a surface of a target object (32) by moving relative to the target object, and includes brushes (2a, 2b, and 2c) which brush the surface of the target object and are aligned and arranged at plural stages in the relatively moving direction, and biasing
units (5 and 6) which allow the brushes to be pressed to and brought
into contact with the target object. The target object is brushed by the brushes at the respective stages with the relative movement. In the above-described sweeping apparatus, the brushes at plural stages are different in hardness, and the brush at the stage where the target object is brushed for the first time is stronger in hardness. Further, in the above-described sweeping apparatus, the brush at the stage where the target object is brushed for the first time is the plate-like brush (2c) , and the brushes at the other stages are brushes formed of a plurality of hairs. Thus, the same effects as those in the embodiments of the electrostatic precipitator can be obtained with the above-described configurations.

WHAT IS CLAIMED IS:
1. An electrostatic precipitator comprising:
a casing which allows a dust-containing gas to flow from an inlet for a gas to an outlet;
a plurality of discharge electrodes which are suspended in a gas flow channel serving as a dust-collecting area in the casing; and
a plurality of movable electrodes which are rotated by forming a loop using a plurality of dust-collecting plates suspended by a pair of endless chains and which include sweeping units for brushing surfaces of the dust-collecting plates being rotated at predetermined positions, wherein
the sweeping unit includes:
an elongated brush which extends in the width direction of the surface of the dust-collecting plate and is brought into contact therewith;
a link mechanism to one end of which the brush is attached and the other end of which is fixed to a fixed member;
a biasing unit which allows the brush to be pressed to and brought into contact with the dust-collecting plate through the link mechanism; and
a restricting unit which restricts the press of the brush so that the brush is prevented from being fitted into a clearance between the adjacent dust-collecting plates.
2. An electrostatic precipitator comprising:
a casing which allows a dust-containing gas to flow from an inlet for a gas to an outlet;
a plurality of discharge electrodes which are suspended in a gas flow channel serving as a dust-collecting area in the casing; and
a plurality of movable electrodes which are rotated by forming a loop
using a plurality of dust-collecting plates suspended by a pair of endless chains and which include sweeping units for brushing surfaces of the dust-collecting plates being rotated at predetermined positions, wherein
the sweeping unit includes:
an elongated brush which extends in the width direction of the surface of the dust-collecting plate and is brought into contact therewith;
a link mechanism to one end of which the brush is attached and the other end of which is fixed to a fixed member; and
a biasing unit which allows the brush to be pressed to and brought into contact with the dust-collecting plate through the link mechanism, and
is attached to the link mechanism while being inclined so that the brush is prevented from being fitted into a clearance between the adjacent dust-collecting plates and the brush is brought into contact with the dust-collecting plates across the clearance.
3. The electrostatic precipitator according to claim 1 or 2, wherein
the link mechanism is configured using a parallelogram link, and the brush and the biasing unit are attached to a front end and a rear end of the parallelogram link, respectively.
4. The electrostatic precipitator according to any one of claims 1 to 3,
wherein
the biasing unit is a spindle, and the link mechanism is rotated by the gravity of the spindle to press the brush to the dust-collecting plate.
5. The electrostatic precipitator according to any one of claims 1 to 3,
wherein
a plurality of brushes are divided and aligned in the width direction
of the dust-collecting plate.
6. The electrostatic precipitator according to claim 5, wherein
the biasing unit is provided for each brush so that each of a plurality of divided and aligned brushes is pressed to and brought into contact with the dust-collecting plate with each biasing force.
7. A sweeping apparatus which brushes a surface of a target object by moving
relative to the target object, the apparatus comprising:
a brush which brushes a surface of the target object;
a link mechanism to one end of which the brush is attached and the other end of which is fixed to a fixed member; and
a biasing unit which allows the brush to be pressed to and brought into contact with the target object through the link mechanism.
8. An electrostatic precipitator comprising:
a casing which allows a dust-containing gas to flow from an inlet for a gas to an outlet;
a plurality of discharge electrodes which are suspended in a gas flow channel serving as a dust-collecting area in the casing; and
movable electrodes which are rotated by forming a loop using a plurality of dust-collecting plates suspended by a pair of endless chains and which include sweeping units for brushing surfaces of the dust-collecting plates being rotated at predetermined positions, wherein
the sweeping unit includes brushes which are formed in an elongated shape extending in the width direction of the dust-collecting plate and which are aligned and arranged at plural stages in the rotational direction, and
biasing units which allow the brushes to be pressed to and brought into
contact with the dust-collecting plate, and
the dust-collecting plates are brushed by the brushes at the respective stages with the rotational movement of the dust-collecting plates.
9. The electrostatic precipitator according to claim 8, wherein
the brush at the upstream stage in the rotational direction of the dust-collecting plates is strong in hardness, and the brush at the downstream stage is weak in hardness.
10. The electrostatic precipitator according to claim 8 or 9, wherein
the brush at the upstream stage in the rotational direction of the dust-collecting plates is a plate-like brush, and the brush at the downstream stage is a brush formed of a plurality of hairs.
11. The electrostatic precipitator according to claim 8, wherein
the brushes at the respective stages are attached while being inclined so that the brushes are prevented from being fitted into a clearance between the adjacent dust-collecting plates and are brought into contact with the dust-collecting plates across the clearance.
12. The electrostatic precipitator according to claim 8, wherein
the biasing unit includes a restricting unit which restricts the press of the brushes to the dust-collecting plate so that the brushes are prevented from being fitted into the clearance between the adjacent dust-collecting plates.
13. The electrostatic precipitator according to claim 8, wherein
a plurality of brushes at the respective stages are divided and aligned
in the width direction of the dust-collecting plate.
14. The electrostatic precipitator according to claim 8, wherein
the brushes at plural stages aligned in the rotational direction of the dust-collecting plates are arranged in the width direction of the dust-collecting plate while being divided into a plurality of sets.
15. The electrostatic precipitator according to claim 14, wherein
the biasing unit is provided for each set so that each set of brushes is pressed to and brought into contact with the dust-collecting plate with each biasing force.
16. A sweeping apparatus which brushes a surface of a target object by moving
relative to the target object, the apparatus comprising:
brushes which brush the surface of the target object and are aligned and arranged at plural stages in the relatively moving direction; and
biasing units which allow the brushes to be pressed to and brought into contact with the target object, wherein
the target object is brushed by the brushes at the respective stages with the relative movement.
17. An electrostatic precipitator comprising:
a casing which allows a dust-containing gas to flow from an inlet for a gas to an outlet;
a plurality of discharge electrodes which are suspended in a gas flow channel serving as a dust-collecting area in the casing; and
a plurality of movable electrodes which are rotated by forming a loop using a plurality of dust-collecting plates suspended by a pair of endless chains and which include sweeping units for brushing surfaces of the
dust-collecting plates being rotated at predetermined positions, wherein
the sweeping unit includes:
an elongated brush which extends in the width direction of the surface of the dust-collecting plate and is brought into contact therewith.