AU776136B2

AU776136B2 - Moving electrode type electric dust collecting apparatus

Info

Publication number: AU776136B2
Application number: AU35412/00A
Authority: AU
Inventors: Takeo Arimitsu; Toshiyuki Eguchi
Original assignee: Hitachi Plant Technologies Ltd; Hitachi Plant Engineering and Construction Co Ltd
Current assignee: Hitachi Ltd
Priority date: 2000-05-19
Filing date: 2000-05-19
Publication date: 2004-08-26
Anticipated expiration: 2020-05-19
Also published as: AU3541200A

Description

S&F Ref: 508820

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FnP( A TA NTA D A TENTT

ORIGINAL

0 00** 0* *000 Name and Address of Applicant: Actual Inventor(s): Address for Service: Invention Title: Hitachi Plant Engineering Construction Co., Ltd.

1-14, Uchikanda 1-chome Chiyoda-ku Tokyo Japan Takeo Arimitsu, Toshiyuki Eguchi Spruson Ferguson St Martins Tower 31 Market Street Sydney NSW 2000 Moving Electrode Type Electric Dust Collecting Apparatus The following statement is a full description of this invention, including the best method of performing it known to me/us:- IP Australia Documents received on: 1 MAY 2000 Bacn No: 5845c 1 MOVING ELECTRODE TYPE ELECTRIC DUST COLLECTING

APPARATUS

Background of the Invention and Related Art Statement The present invention relates to an elecLric dus cullecing apparatus, particularly, to a moving electrode type electric dust collecting apparatus of the type that the dust attached to a dust collecting electrode plate is removed by a brush while moving in a vertical direction the dust collecting electrode plate positioned to face a discharge frame equipped with a discharge electrode.

10 A moving electrode type electric dust collecting apparatus is used for ooooo removing the dust contained in the waste gas of a boiler of a thermoelectric power plant or in the waste gas out of various furnaces used in an iron mill.

Figs. 7 to 10 collectively show schematically the construction of the moving S* electrode type electric dust collecting apparatus.

15 Specifically, Fig. 7 is a cross sectional side view showing the general construction of a moving electrode type electric dust collecting apparatus As shown in the drawing, the moving electrode type electric dust collecting apparatus 10 comprises a casing 12, a lower hopper 13 arranged in a lower portion of the casing 12, a large number of discharge frames 14 arranged within the casing 12, and a large number of moving electrodes 15 attached thereto. The dust contained in a waste gas 17, which is introduced from an inlet flue 16 into the casing 12, is attached to the moving electrodes acting as dust collecting electrodes based on the principle of the electric dust collection. As a result, a clean gas, from which the dust has been removed, is discharged from an outlet flue 18. The dust collected by the dust collecting electrodes drops into the hopper 13 so as to be taken out through a discharge port 20 by a dust discharge mechanism (not shown).

2 Fig. 8 shows the apparatus 10 as seen in the direction denoted by arrows A-A shown in Fig. 7. As shown in the drawing, the discharge frames 14 are fixed a predetermined distance apart from each other within the casing 12. Each of the discharge frames 14 is supported by a hanging frame 24 hanging from an insulator 22. The moving electrodes 15 are arranged to surround alternative frames 14 that are fixed a predetermined distance apart from each other.

Fig. 9 is an oblique view showing the construction of the moving electrode 15. As shown in the drawing, a pair of endless chains 30, 30 are S 10 respectively wound around a driving wheel 26, 26 arranged at an upper $oooo portion and a lower roller 28, 28 at a lower position. A plurality of dust collecting electrode plates 32 are mounted at central portions 33 to the pair of endless chains 30, 30 to form a loop as a whole. A driving shaft 34 of the driving wheel 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 in mesh with the driving wheel 26. The loops each formed by a plurality of dust collecting electrode plates 32 are moved around alternative discharge frames 14.

Fig. 10 shows the arrangement of the lower portion of the moving electrodes 15. The dust collecting electrode plates 32, which are mounted to the endless chains 30, 30, are moved around the discharge frame 14.

The dust collecting electrode plate 32 moved downward is turned upward at the position of the lower roller 28 and, then, is moved upward. A pair of rotary brushes 36, 38 (hereinafter referred to collectively as a "brush means" and denoted by a reference numeral 40), are arranged to sandwich the dust collecting electrode plate 32 immediately after the upward movement. The brush means 40 is arranged for every lane. These brushes 36, 38 are prepared by mounting short metal wires around a rotary shaft. As shown 3 in the drawing, the brush 36 is rotated clockwise in the drawing, and the other brush 38 is rotated counterclockwise. The dust attached to the surfaces of the dust collecting electrode plates 32 is brushed to fall downward. The dust collecting eiecruue piaLe 32 having the dust attached to the surfaces removed by the brush means 40 is moved upward. Then, the dust within the waste gas is collected again on the surfaces of the dust collecting electrode plate 32 by the discharge frame 14 in a predetermined discharge region by the principle of the electric dust collection. The dust collecting electrode plate 32 having the dust collected on both surfaces is 10 moved again downward.

$oooo Summary of the Invention Where the dust collecting apparatus is relatively large, the apparatus includes fifty to a hundred lanes of the moving electrodes 15. The number of driving devices for driving the moving electrodes 15 and the number of driving devices for driving the brush means 40 are equal to the number of ":lanes of the moving electrodes and to the number of the brush means respectively. It was ordinarily in the past to arrange the driving devices by the number equal to the number of mechanisms to be driven, giving rise to the problem that the facility cost of the driving devices was markedly increased.

What should also be noted is that the driving devices, which were commonly connected to a single power source system, were driven independently. Therefore, even if there was unevenness in the cleaning capability of the brush means, it was impossible to adjust the cleaning capability of the individual brush means independently.

An object of the present invention, which was achieved in view of the above-noted problems inherent in the conventional technique, is to provide a moving electrode type electric dust collecting apparatus that permits actuating the driving system by a common driving source and also permits operating the driving system simultaneously so as to improve the dust collecting efficiency. The present invention is also intended to provide a moving electroue type electric dust cui cltig apparaLus tla pterMiLs decreasing the facility cost of the driving mechanisms for driving the moving electrodes and the brush means so as to increase the investment effect of the facility.

The present invention is directed to a moving electrode type electric dust collecting apparatus, comprising a large number of discharge frames S 10 arranged in a hanging manner a predetermined distance apart from each other within a casing, a large number of moving electrodes each including a plurality of dust collecting electrode plates attached to a pair of endless Schains to form a loop as a whole, said moving electrodes being arranged to circulate about alternative frames, and brush means arranged to rotate at 5 predetermined positions of each moving electrode for brushing the dust collecting electrode plate. In the moving electrode type electric dust collecting apparatus of the present invention, a plurality of adjacent brush means are driven simultaneously by a common driving source. Also, the driving source of the moving electrode is driven such that the dust collecting electrode plates of each moving electrode corresponding to the plurality of the brush means are circulated to have a difference in phase from the dust collecting electrode plates of at least one other moving electrode. In this case, it is possible to drive the plural moving electrodes corresponding to the plural brush means by a common driving source. Also, the group of the brush means driven by the common driving source may be the same as or different in combination from the group of the moving electrodes moved by the common driving source. Of course, it is possible for the driving sources of the moving electrodes to be individual driving sources to produce a difference in phase in the circulation of the moving electrodes.

Brief Description of the Drawing Fig. i shows the arrangement in the lower portion of the moving electrodes according to one embodiment of the present invention; Fig. 2 is a cross sectional view showing the driving mechanism of the brush means according to one embodiment of the present invention; Fig. 3 is an oblique view showing the driving mechanism of the brush means according to one embodiment of the present invention; 10 Fig. 4 is an oblique view showing the driving mechanism of the .oe.oi moving electrode; Fig. 5 is an oblique view showing the construction of the dust collecting electrode according to one embodiment of the present invention; Fig. 6 shows the operating state of the brush means according to one 15 embodiment of the present invention; ~Fig. 7 is a side cross sectional view showing the general construction Sof a moving electrode type electric dust collecting apparatus; Fig. 8 is a cross sectional view as seen in the direction denoted by arrows A-A in Fig. 7; Fig. 9 is an oblique view showing the general construction of the moving electrode; and Fig. 10 shows the general arrangement in a lower portion of the moving electrode.

List of Reference Numerals 12 casing; 14.. discharge frame; moving electrode; 26 driving wheel; endless chain; 32 dust collecting electrode plate; brush means; 60, 174 driving source.

Detailed Description of the Preferred Embodiment Fig. 1 shows the arrangement in the lower portion of a moving electrode according to one embodiment of the present invention. The entire structure of the moving electrode type electric dust collecting apparatus is similar to that described previously in the prior art portion hereof.

Therefore, the same reference numeral denotes the same constituent of the apparatus.

As shown in Fig. 1, moving electrodes 15A, 15B and 15C are arranged S 10 in parallel. The dust collecting electrode plates 32A, 32B, 32C attached to .oe.oi the endless chains 30 and moving downward are turned at the positions of the lower rollers 28 and, then, are moved upward. Brush means 40A, 40C are arranged in a manner to sandwich the dust collecting electrode plates 32A, 32B, 32C, respectively, that begin to be moved upward. A pair of brushes 36A, 38A constituting the brush means 40A are rotated in opposite directions as denoted by arrows in the drawing so as to brush away downward the dust attached to the surfaces of the dust collecting electrode plate 32A. The brush means 40B and 40C are of identical.

These brush means 40A, 40B, 40C are driven by a common driving source, as shown in Figs. 2 and 3. Specifically, the rotary shaft of each brush extends through a wall material 21 of the casing and the lower end portion of the rotary shaft is supported by a bearing 41 positioned outside the casing. A gear 46A and a sprocket 50A are mounted to the rotary shaft 42A of the brush 36A. A gear 48A is mounted to the rotary shaft 44A of the brush 38A. A gear 46B and a sprocket 50B are mounted to the rotary shaft 42B of the brush 36B. A sprocket 50C is mounted to the rotary shaft 42C of the brush 36C. Further, a sprocket 51C and another sprocket 52C are mounted to the rotary shaft 44C of the brush 38C.

As shown in Fig. 3, a brush means 40D is positioned adjacent to the brush means 40C. A gear 46D and a sprocket 50D are mounted to a rotary shaft 42D of a brush 36D, and a gear 48D and a sprocket 52D are mounted to a rotary shaft 44D of a brush 38D. Further, a sprocket 58 is mounted to a rotary shaft 62 of a driving source In the construction described above, the sprocket 58, the sprocket the sprocket 51C and the sprocket 50D are pivotally joined with a chain 64. If the rotary shaft 62 of the driving source 60 is rotated clockwise, the tuning effort of the rotary shaft 62 is transmitted to each of S 10 the sprockets the 50C, 51C, 50D through chain 64 so as to permit the rotary ooooog shafts 42C and 42D to be rotated clockwise and to permit the rotary shaft 44C to be rotated counterclockwise. Also, since the sprocket 52C and the sprocket 52B are joined to each other through a chain 66, the rotary shaft 44B is rotated counterclockwise by the rotary shaft 44C. Also, since the 15 gear 46B is engaged with the gear 48B, the rotary shaft 42B is rotated clockwise by the rotary shaft 44B. Likewise, the rotary shaft 42A is rotated clockwise and the rotary shaft 44A is rotated counterclockwise by transmission of the turning effort.

Further, when the rotary shaft 42D is rotated, the turning effort is transmitted to the rotary shaft 44D through the gears 46D and 48D.

Likewise, the adjacent rotary shafts (not shown) are also rotated by the turning effort.

As a result, a plurality of adjacent brush means 40 can be driven simultaneously by the common driving source 60 through the rotation transmitting mechanism of the gears, sprockets and chains. In this embodiment, the driving source 60 is arranged in the center, and three brush means 40 arranged on each side of the driving source 60 totaling six brush means are driven simultaneously by the common driving source In the moving electrode type electric dust collecting apparatus including sixty lanes of moving electrodes 15, all the brush means can be driven simultaneously by 10 driving sources by applying the similar construction to the other brush means so as to markedly simplify the driving apparatus.

Also, in the embodiment of the present invention described above, a plurality of adjacent brush means are driven simultaneously by the common driving source, and a plurality of moving electrodes corresponding to these plural brush means are driven by the common driving source, with the result that the driving apparatus can be markedly simplified.

S 10 Fig. 4 shows the driving mechanism of the moving electrodes. As ooooo shown in the drawing, moving electrodes 15A, 15B, 15C and 15D are arranged in parallel. In these moving electrodes, the dust collecting Selectrode plates, which are attached to endless chains 30 and are moved upward, are turned at the positions of the driving wheels 26A, 26B, 26C and 26D, respectively, so as to be moved downward. Driving shafts 34A, 34B, 34C and 34D of these driving wheels are pivotally supported within the casing (not shown), and double raw driving sprockets 172A, 172B, 172C and 172D are respectively mounted to one end portion of each driving shafts projecting outside the casing.

A common driving source 174 is arranged outside the casing.

Turning effort force produced by the driving source 174 is transmitted to the sprocket 172B and 172C through a sprocket 176 and a chain 178. As a result, the driving shafts 34B and 34C integral with the sprockets 172B and 172C are rotated so as to drive the moving electrodes 15B, 15C. Further, the rotation of the sprocket 172B is transmitted to the sprocket 172A through the chain 180 so as to rotate the driving shaft 34A integral with the sprocket 172A, thereby driving the moving electrode 15A. Likewise, the rotation of the sprocket 172A is transmitted to a sprocket (not shown) of the adjacent moving electrode through a chain 182 so as to drive the adjacent moving electrode. The moving electrode 15D and another moving electrode (not shown) positioned adjacent thereto are similarly driven by the similar chain transmission of the turning effort.

As a result, a plurality of adjacent moving electrodes 15 can be driven by the common driving source 174 through the rotation transmitting mechanism consisting of the sprockets and chains. In this embodiment, the driving source 174 is arranged in the center, and three lanes of moving electrodes 15 arranged on each side of the driving source 174 totaling six lanes of the moving electrodes 15 are driven by the common driving source 174. In the moving electrode type electric dust collecting apparatus including sixty lanes of moving electrodes, all the moving electrodes can be driven by ten sets of driving source by applying the similar construction to the other moving electrodes so as to markedly simplify the driving apparatus.

In addition to the features described above, the dust collecting electrode plates of each of the moving electrodes corresponding to a plurality of adjacent brush means are driven to have phase difference from the dust collecting electrode plates of the other moving electrodes in this embodiment of the present invention. Specifically, the dust collecting electrode plate 32B of the moving electrode 15B is driven with a phase difference of relative to the phase of the dust collecting electrode plate 32A of the moving electrode 15A, as shown in Fig. 1. Likewise, the dust collecting electrode plate 32C of the moving electrode 15C is driven with a phase difference of 600 relative to the phase of the dust collecting electrode plate 32A of the moving electrode 15A. Similarly, the dust collecting electrode plates 32 of the moving electrodes 15 of the six lanes corresponding to a plurality of brush means driven by the common driving source 60 are driven with phase differences of 30' 600, 900, 1200 and 1500 such that a phase difference of 300 is provided between adjacent dust collecting electrode plates.

The reason for providing a phase difference in the driving of the dust collecting electrode plates 32 is considerably related to the outer contour of the dust collecting electrode plate 32. Specifically, as shown in Fig. 5, the dust collecting electrode plate 32 is prepared by reinforcing the peripheral portion of a thin steel plate 72 with relatively thick vertical frames 74 and relatively thick lateral frames 76 in view of, mainly, reduction in weight and improvement in mechanical strength of the dust collecting electrode plate 32.

Figs. 6(A) and 6(B) show how the metal hairs 78 of the brushes arranged at predetermined positions act on the dust collecting electrode S. 55 plate 32. Specifically, deformation of the metal hairs 78 is relatively small when the thin steel plate 72 of the dust collecting electrode plate 32 passes through the clearance between the pair of the brushes 36 and 38, as shown in Fig. leading to a small tuning effort of the brushes 36, 38. Also, since the pressure of the metal hairs 78 against the steel plate 72 is low, the frictional resistance between the metal hair and the steel plate is low when the steel plate 72 passes through the brush means 40. On the other hand, deformation of the metal hairs 78 of the brush is high when the lateral frames 76 pass through the brush means 40, as shown in Fig. leading to a high turning effort of the brushes 36 and 38. Also, since the pressure of the brushes against the lateral frames 76 is high, the frictional resistance is high when the lateral frames 76 pass through the brush means Calculation shows that the frictional resistance and the turning effort required for the brush means 40 when the lateral frames 76 pass through the brush means 40 are about twice as high as those in the case where the steel plate 72 passes through the brush means It follows that, where a plurality of moving electrodes 15 and a plurality of brush means 40 are driven respectively by common driving sources under the state that there is no phase difference between the dust collecting electrode plates of a plurality of adjacent moving electrodes 15 as shown in Fig. 10, the lateral frames 76 of the plural dust collecting electrode plates 32 pass simultaneously through the brush means 40, results in a heavy load concentrating thereto It is necessary to allow the common driving sources and the transmitting mechanisms to be capable of withstanding such a heavy loads, leading to an increased facility cost.

S• 10 In the embodiment of the present invention, however, the dust oo 0o collecting electrode plates of a plurality of adjacent moving electrodes 15 are arranged to have a difference in phase from each other as shown in Fig. 1.

00 00 Since a plurality of moving electrodes 15 and a plurality of brush means .are driven by common driving sources, the lateral frames 76 of the dust 15 collecting electrode plates 32 do not pass across the brush means 40, thereby equalizing such a heavy load applied to the common driving sources of the brush means 40 and the moving electrodes 15, and the transmitting mechanisms. It follows that the capacity and the mechanical strength of the common driving sources and the transmitting mechanisms can be diminished so as to save the facility cost.

In the embodiment described above, a plurality of adjacent brush means are driven simultaneously by a common driving source, and a plurality of moving electrodes corresponding to these brush means are driven by a common driving source of the similar mechanism. However, the present invention is not limited to the particular embodiment. For example, it is possible for a group of brush means driven by a common driving source to be different in combination from a group of moving electrodes driven by a common driving source. Specifically, it is not

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*5S5 S S S* S absolutely necessary for the number of brush means driven by a common driving source to be equal to the number of moving electrodes driven by a common driving source. To be more specific, it is possible to use a common driving source for commonly driving the brush means mounted to the moving electrodes for six lanes and to use a common driving source for commonly driving the moving electrodes for three lanes. Alternatively, it is possible to use a common driving source for driving the brush means alone while using a single driving source to independently drive each of the moving electrodes.

10 In the embodiment described above, the dust collecting electrode plates of the adjacent moving electrodes are made different from each other in phase by 300. However, the present invention is not limited to the particular embodiment. To be more specific, it suffices for the dust collecting electrode plates of at least one moving electrode to be different in 15 phase from the dust collecting electrode plates of the moving electrodes corresponding to a plurality of brush means driven commonly by the same common driving source. For example, where the brush means driven by the common driving means covers six lanes of the moving electrodes, it is possible for the dust collecting electrode plates of the moving electrodes corresponding to a plurality of brush means to have phase differences of the combinations given below.

lane 1 lane 2 lane 3 lane 4 lane 5 lane 6 Example 1 00 300 600 00 300 600 SExample 2 00 00 900 900 1 1800 1800 Example 3 00 900 00 900 00 900 Of course, the scope of the present present invention.

combinations given above fall within the technical invention and produce the prominent effect of the The moving electrode type electric dust collecting apparatus of the present invention permits decreasing the facility cost of the driving mechanism. It is also possible to decrease the facility cost of the driving mechanism tor driving the moving electrodes.

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Claims

1. A moving electrode type electric dust collecting apparatus including a plurality of lanes of moving electrodes circulated around discharge frames equipped with discharge electrodes and a plurality of brush means for brushing the dust collecting electrode plates mounted to each moving electrode, characterized by comprising: a rotation transmitting mechanism for rotating a plurality of brush means simultaneously; a common driving source for supplying a turning effort to said S. o 10 rotation transmitting mechanism; and moving electrode driving means for moving around a plurality of moving electrodes that are to be brushed by a group of brush means rotated simultaneously such that a phase difference is generated at the brushing position among the dust collecting electrode plates included in a plurality of 0 moving electrodes.

The moving electrode type electric dust collecting apparatus according to claim 1, characterized in that a plurality of moving electrodes corresponding to a plurality of brush means are driven by a common driving 0@ S .:ago: source.

3. The moving electrode type electric dust collecting apparatus according to claim 1, characterized in that said moving electrode driving means provides a driving means for driving respective moving electrode independently.

4. The moving electrode type electric dust collecting apparatus according to claim 2, characterized in that a group of brush means driven by a common driving source differs in combination from a group of moving electrodes driven by a common driving source. A moving electrode type electric dust collecting apparatus, comprisinga large number of discharge frames arranged in a hanging manner a predetermined distance apart from each other within a casing, a large number of moving electrodes each including a plurality of dust collecting electrode plates attached to a pair of endless chains to form a loop as a whole, said moving electrodes being arranged to move around alternative frames, and brush means arranged to rotate at a predetermined position of each moving electrode for brushing the dust collecting electrode plate, characterized in that a io plurality of adjacent brush means are rotated simultaneously by a common driving source, and that the apparatus includes a common driving source for moving around a plurality of moving electrodes such that the dust collecting electrode plates of the moving electrodes corresponding to a plurality of brush means are rotated to generate a phase difference 0* C from the dust collecting electrode plates attached to at least one moving electrode. 6 :o i15 6. A moving electrode type electric dust collecting apparatus, said apparatus being substantially as described herein in relation to any one embodiment with reference to Figs. 1 to 6 of the drawings. DATED this Nineteenth Day of May, 2000 Hitachi Plant Engineering Construction Co., Ltd. Patent Attorneys for the Applicant -go, SPRUSON FERGUSON R:\LIBFI27675.doc:GMM