CN1939594A - The moving electrode of the moving electrode type electric dust collecting device - Google Patents

Abstract

The invention aims to provide a movable electrode of a movable electrode type electric dust collector, which can increase the length of a dust collecting pole plate, is beneficial to simplifying the structure of the device and reducing the cost. A movable electrode (18) of a movable electrode type electric dust collector comprises a pair of driving wheels (20), a pair of driven rollers (22), a pair of endless chains (24) stretched between the driving wheels and the driven rollers, and a dust collecting electrode plate (26) suspended on the pair of endless chains (24), wherein the dust collecting electrode plate (26) rotates around a discharge electrode, wherein a 1 st auxiliary roller (32) is additionally arranged at the middle position of a rotating shaft (30) connected with the pair of driving wheels (20), and a 2 nd auxiliary roller (36) is additionally arranged at the middle position of a rotating shaft (34) connected with the pair of driven rollers (22). Permanent magnets are installed on the outer circumference of the 2 nd auxiliary roller.

Description

The moving electrode of the moving electrode type electric dust collecting device

technical field

The present invention relates to an electrode structure of a movable electrode type electric dust collecting device, in particular to a mobile electrode structure in which a plurality of dust-collecting pole plates suspended on an annular cord-shaped body (endless cord-shaped body) rotate and move around a discharge electrode. The mobile electrode of the electrode type electric dust collector.

Background technique

In order to remove dust from boiler exhaust gas of a thermal power station or various furnace exhaust gases, a mobile electrode type electric dust collector as disclosed in JP-A-2001-246284 is used. Fig. 4 is a perspective view showing a schematic structure of a moving electrode used in such a moving electrode type electric dust collecting device. Between a pair of drive sprocket wheels 1 arranged at the top and a pair of driven rollers 2 arranged at the bottom, a pair of endless chains 3, 3 are rotatably stretched as endless cord-shaped bodies. The rectangular dust-collecting pole plate 4 is connected by the middle part 5 of its side edge and installed between a pair of endless chains 3, 3, and a plurality of dust-collecting pole plates 4, 4, . . . are arranged along the chain rotation direction. The shaft 6 of the driving sprocket 1 is rotated by a driving mechanism not shown, and the rotation of the shaft 6 is transmitted to a pair of endless chains 3 and 3 engaged with the driving sprocket 1, forming a plurality of dust collectors in a loop as a whole. The pole plates 4, 4, . . . rotate and move around unshown discharge electrodes.

Fig. 5 is a configuration diagram of the lower part of the mobile electrode 10. The dust collecting pole plate 4 suspended on the endless chain 3 and descending turns U-shaped at the position of the driven roller 2 and turns to rise. Rotating brushes 7 are arranged on the lanes of the moving electrodes 10 at positions sandwiching the dust-collecting plate 4 that has just risen. A discharge electrode 8 is arranged above the rotating brush 7 . During the movement of the dust-collecting plates 4 and 4 in the vertical direction in the lateral direction of the discharge electrode 8, the dust in the exhaust gas is charged by the corona discharge from the discharge electrode 8 and is collected on the surface of each dust-collecting plate 4. . When each dust-collecting pole plate 4 passes through the position where the rotating brush 7 is arranged, the dust attached to the surface of the dust-collecting pole plate 4 is peeled off and removed by the rotating brush 7 .

That is, in this moving electrode type electric dust collector, the following operations are repeated: During the movement of each dust collecting pole plate 4 in the upper dust collecting space where the discharge electrode 8 exists, dust is collected to each dust collecting pole The surface of the plate 4, the dust collection pole plate 4 descends and turns in a U shape at the position of the driven roller 2, and when it turns to rise, the dust attached to the surface of the dust collection pole plate 4 is peeled off and removed by the rotating brush 7. According to this structure, whenever the dust-collecting plate 4 passes through the rotating brush 7, the dust attached to the surface of the dust-collecting plate 4 is surely removed, and the cleanliness of the surface of the dust-collecting plate 4 is restored. Therefore, the thickness of the dust layer that is collected and accumulated on the surface of the dust collecting plate 4 can always be kept very thin.

The dust collection performance of the electric dust collector is greatly influenced by the resistivity of the collected dust. Especially when the resistivity of the dust is as high as 10 ¹² Ωcm or more, if the thickness of the dust layer accumulated on the surface of the dust collecting plate exceeds the specified value, the reverse ionization phenomenon will occur, and the dust collection performance will drop sharply. Since the moving electrode type electric dust collecting device can keep the thickness of the dust layer collected and accumulated on the surface of the dust collecting plate 4 always very thin as mentioned above, it is difficult for the reverse ionization phenomenon to occur. Therefore, this type of moving electrode ESP is mainly used in exhaust air containing high-impedance dust.

In the moving electrode 10, as shown in FIG. In the moving electrode 10 , the dust is removed and the purified process gas is discharged in the direction of arrow B . The dust collection rate largely depends on the residence time of the gas to be processed when it passes through the area of the moving electrode 10 . If the residence time of the gas to be processed is short, the dust collection rate is low, and if the residence time of the gas to be processed is long, the dust collection rate is high.

When the flow rate of the gas to be processed is constant, the larger the width of the moving electrode 10 indicated by the dimension L in the figure, the longer the residence time of the gas to be processed. Therefore, in order to improve the dust collection rate, it is only necessary to increase the width of the moving electrode 10 (in other words, the length of the dust collection pole plate 4 ) as much as possible.

However, if the width of the moving electrode 10 is excessively increased, a practical problem arises. FIG. 6 is a schematic side view of the moving electrode 10 for explaining this problem. That is, in order to reduce the cost, it is necessary to reduce the weight of the dust-collecting pole plate 4, and to make the brush cleaning effect of the rotating brush 7 effective, it is necessary to make the dust-collecting pole plate as thin as possible. Therefore, if the length of such a thin dust-collecting pole plate 4 is excessively increased, then as shown in FIG. , There is a problem that the dust-collecting pole plates 4A, 4B in a horizontal state are excessively bent. When the bending becomes large, a large bending stress is generated on the electrode plate itself, and plastic deformation occurs. If the plastic deformation gradually increases, it will also have a bad influence on the coupling part 5, and it will develop to the point that the dust collecting plate 4 falls off from the endless chain 3, or the meshing between the endless chain 3 and the driving sprocket 1 will not match, resulting in The operation is not smooth, and at the same time, the change of the distance from the discharge electrode induces a spark.

Therefore, in the existing mobile electrode type electric dust collecting device, as a method of improving the dust collection rate, as shown in Fig. 7, the unitized mobile electrodes 10 are arranged in the front stage along the flow direction of the gas to be treated in multiple stages. The structure of the mobile electrode 10A and the subsequent mobile electrode 10B. However, such a structure complicates the structure of the device, leading to an increase in cost.

Contents of the invention

The purpose of the present invention is to improve the above-mentioned shortcomings of the prior art, and provide a movable electrode for a movable electrode type electric dust collecting device which can increase the length of the dust collecting pole plate and help simplify the structure of the device and reduce the cost.

In order to achieve the above object, the moving electrode of the mobile electrode type electric dust collecting device of the present invention is equipped with a dust collecting pole plate rotating around the discharge electrode in the electric dust collecting device, and it is characterized in that: On the turning path, an auxiliary roller that is in rotational contact with the inner surface of the revolving dust-collecting pole plate is set. In this case, it is only necessary to arrange the auxiliary roller on the reversed portion of the rotation direction.

In addition, the moving electrode of the moving electrode type electric dust collecting device of the present invention has a pair of driving wheels arranged above, a pair of driven rollers arranged below, and a roller stretched between the driving wheels and the driven rollers. A pair of ring-shaped cords and a plurality of dust-collecting plates suspended on the pair of ring-shaped cords, the plurality of dust-collecting plates rotate and move around the discharge electrode, characterized in that: At the middle position of the rotating shaft of a pair of driving wheels, a first auxiliary roller is attached to suppress the bending of the moving dust collecting pole plate, and at the middle position of the rotating shaft connecting the pair of driven rollers, a first auxiliary roller is attached to suppress the moving. The second auxiliary roller for bending the dust collection plate. In addition, the endless cord can be interpreted as broadly as possible, including endless chains and endless wires.

The moving electrode may have a structure in which a permanent magnet is attached to the outer periphery of the second auxiliary roller. In addition, the moving electrode may be formed by stretching an annular cord-shaped body between the first auxiliary roller and the second auxiliary roller, and connecting the central parts of the plurality of dust-collecting electrode plates to the corresponding annular cord-shaped bodies. Structure. In addition, the structure may be such that the endless cable-shaped body is a chain, and the driving wheel is a driving sprocket meshed with the chain. Alternatively, as a steel cord, the endless cord-like body is desirably a twisted-strand cord construction. In addition, the structure may be such that the first and second auxiliary rollers are arranged at one position in the center of the pole plate. In addition, at least one of the first and second auxiliary rolls is arranged at two or more locations along the longitudinal direction of the electrode plate 4 .

The first auxiliary roller or the second auxiliary roller in the present invention supports the weight of the dust-collecting electrode plate and suppresses its bending when the dust-collecting electrode plate turns in a U-shape at the position of the driving wheel or the driven roller and becomes horizontal. . Therefore, according to the moving electrode of the moving electrode type electric dust collecting device in this embodiment, the length of the dust collecting plate can be increased, which helps to simplify the structure of the device and reduce the cost.

Description of drawings

Fig. 1 is a schematic perspective view showing the first embodiment of the moving electrode of the present invention;

Fig. 2 is the front view showing the main structure of the moving electrode type electric dust collecting device with the moving electrode of the present invention;

Fig. 3 is a schematic perspective view showing a second embodiment of the moving electrode of the present invention;

4 is a perspective view showing a schematic structure of a prior art mobile electrode;

FIG. 5 is a diagram showing a lower configuration of a conventional moving electrode;

FIG. 6 is a schematic side view for explaining problems of conventional moving electrodes;

Fig. 7 is a perspective view showing an arrangement example of conventional moving electrodes.

Detailed ways

Fig. 1 is a schematic perspective view showing a first embodiment of a moving electrode of a moving electrode type electric dust collector according to the present invention. A pair of endless chains 24 , 24 are rotatably stretched as endless cord-shaped bodies between a pair of driving wheels 20 arranged at the upper portion and a pair of driven rollers 22 arranged at the lower portion. A plurality of dust-collecting pole plates 26, 26, ... are suspended on a pair of ring metal wires 24, 24 by locking with a suspension member 28 at an intermediate position in the width direction thereof. In addition, in FIG. 1, for convenience of description, most of the dust collection electrode plate 26 is omitted from illustration.

The pair of driving wheels 20 are connected by a rotating shaft 30 . At an intermediate position of the rotating shaft 30, a first auxiliary roller 32 is attached. The first auxiliary roller 32 is formed to have substantially the same diameter as the drive pulley 20 . The pair of driven rollers 22 are connected by a rotating shaft 34 , and a second auxiliary roller 36 is attached to an intermediate position of the rotating shaft 34 . The second auxiliary roller 36 is formed to have substantially the same diameter as the driven roller 22 . A permanent magnet 37 is attached to the outer periphery of the second auxiliary roller 36 .

A driving mechanism (not shown) is connected to one end of the rotating shaft 30 , and the rotating shaft 30 is rotated by the driving mechanism so that the driving wheels 20 , 20 and the first auxiliary roller 32 rotate integrally. The rotation of the driving wheels 20, 20 is transmitted to a pair of endless chains 24, 24, and a plurality of dust collecting plates 26, 26 ... which form a loop as a whole rotate and move around an unillustrated discharge electrode.

FIG. 2 is a front view showing a main structure of a moving electrode type electric dust collector having the moving electrode 18 having the above-mentioned structure. In the dust collecting space, a plurality of discharge electrodes 38 are arranged in parallel at predetermined intervals, and a plurality of moving electrodes 18 are arranged so as to surround these discharge electrodes 38 every other. The dust-collecting pole plate 26 suspended on the endless chain 24 and descending turns U-shaped at the position of the driven roller 22 and turns to rise. Rotating brushes 40 are arranged on the path of each moving electrode 18 at a position sandwiching the dust-collecting plate 26 that has just risen.

Processed gas, containing high-impedance dust, flows in a direction perpendicular to the paper. During the movement of the dust-collecting plates 26 and 26 in the dust-collecting space above the rotating brush 40 along the vertical direction in the lateral direction of the discharge electrode 38, the dust being processed is charged due to the corona discharge from the discharge electrode 38 and is charged. Collected on the surface of each dust collecting pole plate 26. When each dust-collecting pole plate 26 passes through the position where the rotating brush 40 is arranged, the dust adhering to the surface of the dust-collecting pole plate 26 is peeled off and removed by the rotating brush 40 .

That is, in this moving electrode type electric dust collecting device, the following operations are repeated: During the movement of each dust collecting pole plate 26 in the upper dust collecting space where the discharge electrode 38 exists, dust is collected on each dust collecting pole plate 26, the dust collecting pole plate 26 descends and turns in a U shape at the position of the driven roller 22, and after turning to rise, the rotating brush 40 peels off and removes the dust attached to the surface of the dust collecting pole plate 26.

The dust-collecting pole plate 26 rises and turns in a U shape at the position of the drive wheel 20, and when turning to descend, during its movement, as shown in FIG. 1, the dust-collecting pole plate 26 becomes a horizontal state. Therefore, the dust collecting plate 26A tends to bend. However, according to the moving electrode of this embodiment, the first auxiliary roller 32 is present. Since the first auxiliary roller 32 rotates in constant contact with the lower surface of the dust collecting electrode plate 26 and supports the weight of the dust collecting electrode plate 26A, the bending of the dust collecting electrode plate 26A is suppressed.

The dust-collecting pole plate 26 descends and turns in a U-shape at the position of the driven roller 22, and when it turns to rise, it becomes a horizontal state during its movement. Therefore, the dust collecting plate 26B tends to bend. However, according to the moving electrode of this embodiment, the second auxiliary roller 36 exists at this position, and the permanent magnet 37 is attached to the outer periphery of the second auxiliary roller 36 . In addition, the dust collection pole plate 26 is made of a magnetic material such as a carbon steel plate. Therefore, the center part of the dust collecting pole plate 26B is attracted to the outer periphery of the 2nd auxiliary roller 36 by the appropriate magnetic force of the permanent magnet 37, and bending is suppressed.

However, further study on the magnetic force of the permanent magnet 37 is required. If the magnetic force is too small, the desired attracting effect cannot be obtained. In addition, if the magnetic force is too large, the moving operation of the dust collecting pole plate 26B at the time of U-turn at the position of the driven roller 22 cannot be performed smoothly.

As described above, in the moving electrode 18 of the present embodiment, the first auxiliary roller 32 supports the weight of the dust collecting pole plate 26 when the dust collecting pole plate 26A turns in a U-shape at the position of the driving wheel 20 and becomes horizontal, and suppresses the weight of the dust collecting pole plate 26. its curved. Moreover, the 2nd auxiliary roller 36 attracts the dust collection pole plate 26B by magnetic force when the dust collection pole plate 26B turns U-shape at the position of the driven roller 22, and becomes a horizontal state, and suppresses its bending. Therefore, according to the moving electrode 18 of the moving electrode type electric dust collecting device in this embodiment, the length of the dust collecting plate 26 can be increased, which helps to simplify the structure of the device and reduce the cost.

Fig. 3 is a schematic perspective view showing a second embodiment of the moving electrode of the moving electrode type electric dust collector of the present invention. In FIG. 3 , elements assigned the same reference numerals as in FIG. 1 have the same functions as those described in the first embodiment, and description thereof will be omitted. In the moving electrode 18A of the second embodiment, the first auxiliary roller 42 is provided at the middle position of the rotating shaft 30 , and the second auxiliary roller 44 is provided at the middle position of the rotating shaft 34 . An endless wire 46 is stretched between the first auxiliary roller 42 and the second auxiliary roller 44 . The center part of each dust collecting electrode plate 26 is connected with this ring wire 46 by the connection member 48. As shown in FIG. Therefore, each dust-collecting plate 26 moves while its both ends in the longitudinal direction are supported by the endless chains 24 , 24 by the suspension members 28 , and its central portion is supported by the ring wire 46 by the connecting member 48 . Therefore, even when the position of the driving wheel 20 or the driven roller 22 turns in a U-turn to become a horizontal state, bending and stable movement can be suppressed. Therefore, according to the moving electrode 18A of the moving electrode type electric dust collecting device of this embodiment, the length of the dust collecting plate 26 can be increased, which helps to simplify the structure of the device and reduce the cost.

In each of the above-described embodiments, the case where only the first auxiliary roller or the second auxiliary roller is arranged at one position at a position corresponding to the center of the dust collecting electrode plate 26 is shown. However, the present invention is not limited thereto, and two or more first auxiliary rollers or second auxiliary rollers may be arranged at positions where the dust collecting electrode plate 26 is roughly equally divided.

Claims (9)

1. A mobile electrode of an electric dust collecting device, which is equipped with a dust collecting pole plate that rotates around the discharge electrode in the electric dust collecting device. The inner surface of the rotating dust-collecting plate rotates in contact with the auxiliary roller. 2. The mobile electrode of the electric dust collecting device according to claim 1, characterized in that: The auxiliary roller is arranged on a reversed portion of the rotation direction. 3. A moving electrode of a moving electrode type electric dust collector, which has a pair of driving wheels arranged above, a pair of driven rollers arranged below, and a pair of driven rollers stretched between the driving wheels and driven rollers. For the annular cord-shaped body and the plurality of dust-collecting pole plates suspended on the pair of annular cord-shaped bodies, the plurality of dust-collecting pole plates rotate and move around the discharge electrode, characterized in that: At the middle position connecting the pair of driving wheel rotation shafts, a first auxiliary roller is attached to suppress the bending of the dust collecting plate during movement, and at the middle position connecting the pair of driven roller rotation shafts, a first auxiliary roller is attached to prevent movement. The second auxiliary roller in the bending of the dust collection plate. 4. The moving electrode of the moving electrode type electric dust collecting device according to claim 3, characterized in that: A permanent magnet is mounted on the outer periphery of the second auxiliary roller. 5. The moving electrode of the moving electrode type electric dust collecting device according to claim 3, characterized in that: Between the first auxiliary roller and the second auxiliary roller, an endless cord-shaped body is stretched, and the central parts of the plurality of dust collecting electrode plates are respectively connected to the endless cord-shaped body. 6. The moving electrode of the moving electrode type electric dust collecting device according to claim 3, characterized in that: The endless cable-shaped body is a chain, and the driving wheel is a sprocket engaged on the chain. 7. The moving electrode of the moving electrode type electric dust collecting device according to claim 3, characterized in that: The ring-shaped cable-shaped body is a steel cable. 8. The moving electrode of the moving electrode type electric dust collecting device according to claim 3, characterized in that: The first and second auxiliary rollers are arranged at one position in the center of the pole plate. 9. The moving electrode of the moving electrode type electric dust collecting device according to claim 3, characterized in that: At least one of the first and second auxiliary rolls is arranged at two or more locations along the longitudinal direction of the electrode plate 4 .

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