Title of Invention	AN ELECTROSTATIC PRECIPITATOR WITH A DEVICE FOR THE SUSPENDING, GUIDDING AND RAPPING OF ONE OR MORE COLLECTING ELECTRODES
Abstract	(57) Abstract: A device in an electrostatic precipitator for suspending, controlling and rapping one or more collecting electrodes (2) arranged essentially vertically in one or more substan¬tially parallel rows (1), said device comprising for each row (1) a substantially hori¬zontally oriented carrier element (3), to which the upper ends of the collecting elec¬trodes (2) are attached, connecting elements (4a, 4b) which connect the carrier ele¬ment to the casing (5) of the electrostatic precipitator control means (11a, lib, 12a, 12b, 13, 14a, 14b) for controlling the motion of each row (1) of collecting electrodes hi the transverse and/or longitudinal direction of the electrostatic precipitator, and a rapping mechanism (6) for rapping the collecting electrodes (2) of each row, compris¬ing a rapping means (7), such as a rapping hammer, and an anvil (9) connected to the cagier element (3). The carrier element (3) of each row is separately suspended by means of said connecting elements (4a, 4b). thereby permitting, during rapping, a minimum horizontal pivoting motion restricted to each row (1) of collecting elec¬trodes and occurring in the longitudinal direction of the electrostatic precipitator.

Title of Invention

AN ELECTROSTATIC PRECIPITATOR WITH A DEVICE FOR THE SUSPENDING, GUIDDING AND RAPPING OF ONE OR MORE COLLECTING ELECTRODES

Abstract

(57) Abstract: A device in an electrostatic precipitator for suspending, controlling and rapping one or more collecting electrodes (2) arranged essentially vertically in one or more substan¬tially parallel rows (1), said device comprising for each row (1) a substantially hori¬zontally oriented carrier element (3), to which the upper ends of the collecting elec¬trodes (2) are attached, connecting elements (4a, 4b) which connect the carrier ele¬ment to the casing (5) of the electrostatic precipitator control means (11a, lib, 12a, 12b, 13, 14a, 14b) for controlling the motion of each row (1) of collecting electrodes hi the transverse and/or longitudinal direction of the electrostatic precipitator, and a rapping mechanism (6) for rapping the collecting electrodes (2) of each row, compris¬ing a rapping means (7), such as a rapping hammer, and an anvil (9) connected to the cagier element (3). The carrier element (3) of each row is separately suspended by means of said connecting elements (4a, 4b). thereby permitting, during rapping, a minimum horizontal pivoting motion restricted to each row (1) of collecting elec¬trodes and occurring in the longitudinal direction of the electrostatic precipitator.

Full Text	The present invention relates to a device in an electrostatic precipitator for the sus¬pending, controlling and rapping of one or more collecting electrodes arranged essen¬tially vertically in one or more substantially parallel rows and comprising for each row a substantially horizontally oriented carrier element to which the upper ends of the collecting electrodes are attached, connecting elements which connect the carrier element to the casing of the electrostatic precipitator, control means for controlling the motion of each row of collecting electrodes in the transverse and/or longitudinal direction of the electrostatic precipitator, and a rapping mechanism for rapping the collecting electrodes of each row and comprising a rapping means, such as a rapping hammer, arid an anvil compelled to the carrier element. Electrostatic precipitators are usually composed of a plurality)' of successive precipi¬tation fiends through which dust-laden gas is passed to be cleaned. Each of the preci¬pitation fields is divided into a plurality of parallel gas passages by means of a plura¬lity of juxtaposed, earthed collecting escaroles vertically arranged in rows . These are usually in the form of rectangular, substantially plate-slumped, sex-tonal metal sheets. Vertical discharge electrodes, to which a negative volute is supplied, are arranged in each gas passage. Owing to corona discharges at the discharge electrodes, the dust-laden gas is ionised in the electric field in the gas passages. The negative ions are attracted by the collecting electrodes and, while moving towards these, collide with the dust particles of the gas, which are then charged and separated from the gas by being attracted by the closest collecting electrode, on which they are deposited and build up a dust layer. At regular intervals, the dust layer is loosened, by vibrations, from the collecting electrodes by these being mechanically affected by means of a rapping mechanism. The dust particles then fall into a collecting hopper associated with the respective fields. The rapping mechanism can either be arranged at the top or at the bottom of each row of collecting electrodes and usually comprises a rapping hammer acting in a vertical plane about a rotary shaft which extends horizontally-in the transverse direction of the electrostatic precipitator and to which the rapping hammer thus is connected, and an anvil. The rapping force for cleaning each row of collecting electrodes is generated ■ by the rapping hammer giving a horizontally directed rap via the anvil to a rapping means cooperating with the collecting electrodes, whereby a horizontal motion is imparted to the rapping means. This motion is transferred to the collecting electrodes in the form of a shock wave which spreads across these. Thus, the dust layer accumu¬lated on the collecting electrodes is loosened. A greater or smaller amount of the rapping force is absorbed by the suspension of the collecting electrodes during the cleaning operation. The amount of absorbed rapping force depends on the manner of connecting the collecting electrodes to the suspension and on the manner in which the suspension is connected to the casing of the electro¬static precipitator. The collecting electrodes are usually controlled in the longitudinal as well as in the transverse direction of the electrostatic precipitator so as to be kept m exact positions and, thus, prevent tlashovers. There have been suggested various solutions of 3 in an electrostatic precipita¬tor for the suspending, controlling and rapping of its coalescing electrodes. For instance, EP 0 584 880 discloses a device for cleaning collecting electrodes in an electrostatic precipitator by rapping, the collecting electrodes being vertically arrang¬ed, successively in parallel rows. The collecting electrodes of each rows are, at their upper ends, attached between a pair of horizontally arranged longitudinal rapping beams and suspended from these, said.beams thus also serving as earner elements for the collecting electrodes. The rapping beams rest freely on a pair of supporting beams, between which the upper ends of the collecting electrodes are arranged. The pair of supporting beams rests, in turn, on a frame pertaining to the casing of the electrostatic precipitator. The pair of rapping beams thus is atoned so as to be able to slide, during rapping, horizontally on the supporting beams in the longitudinal direction of the electrostatic precipitator. During cleaning by rapping, the rapping force is transfer¬red in the form of a shock wave by means of a rapping hammer to ail the collecting electrodes of a row via an anvil, which is fixedly mounted on the pair of rapping beams of each row. On each side of the ends of the pair of rapping beams, laminated springs are mounted in the casing and cooperate why transverse so-called stop pins arranged at each end of the pair of rapping beams. A spring-back motion of the pair .of rapping beams to its original positioning is pnnted in connection vat the rapping before the anvil is again hit by the rapping hammer. As a result, the laminated springs control the row of collecting electrodes in the longitudinal direction of the electrosta¬tic precipitator. The laminated springs also serve as control means in the transverse direction of the electrostatic precipitator. A drawback of the thus disclosed device is that a relatively great amount of the rapping force is absorbed by the casing during rapping and, thus, is lost. Besides, for each row of collecting electrodes, the device consists of a large number of components, which makes it mechanically complicated. The mounting of the respective rows is carried out in such a manner that the upper ends of the collecting electrodes are first inserted between the pair of the supporting beams and are temporarily mounted therein by means of bolts. Each rapping beam is then arranged on both sides of the upwardly extending ends of the collecting elec¬trodes and is mounted therein by means of bolts, whereupon the bolts in the pair of supporting beams are removed. The mounting procedure accomplished in this manner thus is complicated and time- of each row will probably also take place inside the electrostatic precipitator, which is a drawback compared with the technique of mounting the row outside the electrostatic precipitator so as to be inserted afterwards. One object of the present invention thus is, in view of that stated above, to provide a new and improved device in an electrostatic precipitator for suspending, controlling and rapping its collecting electrodes-,-said device allowing a more efficient use of the generated rapping force when clearing the collecting electrodes. A further object of the present invention is to provide a device for suspending, controlling and rapping, which is mechanically simpler and, consequently,' easier to mount. These objects are achieved by a device which is of the type stated b>- way of introduc¬tion and which according to the present invention is characterised in that the carrier element of each row is suspended separately by means of connecting elements, which as stated above connect the carrier element to the casing of the electrostatic precipita¬tor, thereby permitting a minimum horizontal pivoting motion restricted to each col¬lecting electrode row and occurring in the longitudinal direction of the electrostatic precipitator. The pivoting motion arising in rapping occurs owing to the separate sus¬pension and thus fully independently of the remaining rows. By a restricted, minimum pivot motion is meant a pivoting motion which is less lain about 5 mm of the carrier element in its longitudinal direction. According to the present invention, the connecting elements of the carrier element preferably comprise two elongate rods, each making an angle a, relative to a vertical axis extending through each rod, in the range of about 5-35°, especially in the range of about 5-15°, in such a manner that said rods are positioned substantially in the plane of the row such that the distance between their lower ends is smaller than between their upper ends. In consequence of the carrier element being separately suspended in the above-mentioned fashion, the row of collecting electrodes will be self-centered after rapping, i.e. the row will immediately return to its correct original position. The smaller the angle a the more movable the actual suspension, which means that a greater amount of the rapping force, relatively seen, will be absorbed by the casing, which results in poorer cleaning. On the other hand, the greater the angle CL the more unresilient the suspension, which also results in poorer cleaning. To achieve optometry cleaning, i.e. to transfer as great an amount as positive of the rapping force to the col¬lecting electrodes, the angle is adjxisted according to the present invention so that as small an amount as possible of the rapping force is absorbed by the casing. Moreover, the angle a should be adjusted so as to prevent too great a pivoting motion of the col¬lecting electrodes. By such suspension, which is mechanically simple and easy to mount, a more efficient cleaning of the collecting electrodes is provided. According to the present invention, the control means of the device consist of upper control elements cooperating with the carrier element, and/or lower control elements cooperating with the lower ends of the collecting electrodes. The upper control ele¬ments preferably consist of upper cam control elements cooperating with the end por¬tions of the carrier element. Advantageously, the cam control elements extend sub¬stantially horizontally in the transverse direction of the electrostatic precipitator through a plurality of rows and thus prevent each row of collecting electrodes from moving in said direction. The upper control elements also serve as control means in the longitudinal direction of the electrostatic precipitator, especially m case of small angles a. By means of these upper control elements, which are mechanically simple and easy to mount, efficient control is achieved. To further improve the control, in addition to the control provided by means of the _upper control elements, lower control elements are preferably arranged at the bottom According to a preferred embodiment of the inventive device, the lower ends of the collecting electrodes are loosely controlled by the lower control elements on the one hand in the transverse direction of the electrostatic precipitator by means of a longi¬tudinally oriented, horizontal pair of rods, between which the lower ends of the col¬lecting electrodes are arranged and, on the other hand, in the longitudinal direction of the electrostatic precipitator by means of spacer members arranged before, after and/or between the collecting electrodes. A further alternative preferred embodiment of the inventive device is characterised in that the lower ends of the collecting electrodes are firmly controlled by the lower con¬trol elements in the transverse as well as longitudinal direction of the electric preci¬pitator by means of longitudinally oriented, horizontal rods, to which the lower ends of the collecting electrodes are attached, preverbal by means of bolts or rivets. A common feature of the lower control is teat. each row of collecting electrodes is controlled in the transverse direction of the electrostatics precipitator by means of transversely oriented lower cam control the ends of said rods. The cam control elements advantageously extend substantially vertically in the transverse direction of the electrostatic precipitator through a number of rows and thus prevent the respective rows of collecting elect codes from in said direc¬tion. By means of these lower control elements, which are mechanically simple and easy to mount, efficient control is achieved. The lower and the upper control accord¬ing to the invention is further designed with regard to thermal expansion. According to the present invention, the anvil of the rapping mechanism is preferably directly fixedly mounted on the upper side of the cannier element and comprises a rap¬ping shoulder, which is the rapping point of the rapping means, whirly is arranged in such a manner that the rapping point is located above the horizontal centre line of the carrier element. According to an alternative embodiment, the anvil can also extend across at least two rows of collecting electrodes in the transverse direction of the elec¬trostatic precipitator. In this case, the anvil, which consists of e.g. a flat iron bar, is also directly fixedly mounted on the upper side of the carrier element of each row. The rapping means of the rappingmechaiusm preferably acts in a vertical plane about a rotary shaft connected thereto and extending horizontally in the transverse direction of the electric precipitator, the rapping means giving the anvil a horizontally directed rap during rapping. In on the embodiment, the rap is given to the anvil either directly or indirectly via the above-mentioned rapping shoulder. A general advantage of the inventive device is that each row of collecting electrodes can be mounted outside the electrostatic and then be inserted. Accordingly, the present invent movies an electrostatic precipitator with a device for the suspending, guiding and rapping of one or more collecting electrodes located essentially vertically in one or more substantially parallel rows, said device comprising for each row a substantially horizontally oriented earner element to which the upper ends of the collecting electrodes are attached, connecting elements which connect the carrier element to the casing of the electrostatic precipitator, guiding means for guiding the motion of each row of collecting electrodes in a transverse a longitudinal direction of electrostatic precipitator, and a rapping mechanism for raping the collecting electrcxles, characterised in that the carrier element of each row is separately suspended by means of said connecting elements, that the connecting elements of the carrier element comprise two elongate rods, each making an angle (a), relative to a vertical axis (V) extending through each rod, in the range of about 5-35° in such a manner that said rods are positioned substantially in the plane of the row such that the distance between their lower ends is smaller than tiie distance between their upper thereby permitting, during rapping, a minimum, horizontal pivoting motion restricted to each row of collecting electrodes in the longitudinal direction of the electrostatic precipitator. The invention will now be described in more detail with reference to the accompany¬ing drawings, in which: Fig. 1 is a schematic vertical section of a device according to the invention in parallel with a row of collecting electrodes in an electrostatic pre¬cipitator. Fig. 2 is a horizontal section towards the collecting electrodes taken along line B-B in Fig. 1. Fig. 3 is an enlarged view of a lower control element in Fig. 2. Fig. 4 is a vertical section towards the collecting electrodes taken along line A-A in Fig. 1. Fig. 1 thus is a schematic vertical section in parallel with a row 1 of collecting electrodes 2 in an electrostatic precipitator, which for each row 1 is provided with a device for suspending, controlling and rapping the collecting electrodes 2. The electrostatic precipitator comprises a plurality of successive precipitation fields, each field consisting of a plurality of parallel rows 1 of earthed collecting electrodes 2, which are vertically arranged in succession in the respective rows. Each row 1 of collecting electrodes consists of substantially plate-.shaped, sectional metal sheets, which between themselves thus form gas passages for the dust-laden gas to be clean¬ed. The gas flow in the electrostatic precipitator occurs horizontally as indicated by arrow G. Between each row 1 of collecting electrodes 2, discharge electrodes (not shown) are accommodated, which are connected to a negative voltage. As indicated in Fig. 1, the collecting electrodes 2 of each row are at their upper ends attached by means of rivets or bolts to a horizontally oriented, flexural rigid earner element in the form of a U-beam 3. The U-beam 3 is in turn separately and movably suspended by means of connecting elements, which in the embodiment illustrated consist of two inclined, elongate round bars 4a, 4b. The round bars 4a, 4b are posi¬tioned in the plane of the row and are oriented in such a manner that their lower ends face each other and make an angle a of about 10° relative to a vertical axis V extend¬ing through the respective round bars. The lower ends of the round bars 4a, 4b are secured to the end portions of the U-beam 3 in the upper flange thereof, and the upper ends of the round bars are secured to the casing 5. Because of this, according to the invention, special suspension of the U-beam 3 and the fact that the collecting elec¬trodes 2 are in direct contact with the U-beam 3, a very small amount of the rapping force is absorbed by the casing 5, which results in efficient cleaning. Besides, the horizontal pivoting motion of the row 1 of collecting electrodes arising during clean¬ing will be minimal. In the illustrated embodiment, the rapping mechanism 6 for cleaning the collecting electrodes 2 of each row is arranged in the centre of the U-beam 3 and comprises a rapping hammer 7, which acts in a vertical plane about a rotary shaft 8 extending horizontally in the transverse direction of the electrostatic precipitator, and an anvil 9. As shown in Fig. 1, the anvil 9 in the form of an L-beam is directly fixedly mounted by means of bolts on the upper side of tile U-beam 3 and comprises a rapping shoul¬der 10. The U-beam 3 thus serves as carrier element as well as rapping means for tile collecting electrodes 2. During cleaning, the U-beam 3 is subjected to a horizontany directed rapping hammer 7 giving the rapping shoulder 10 arranged on the anvil 9 a rap, which is transferred in the form of a shock wave to the collecting electrodes 2 via the carrier beam 3. The rapping point of the rapping hammer 7 thus is placed in such a manner that it is located above the horizontal centre line C of the U-beam 3, which is also evident from Fig. 4. The shock wave spreads downwards along all the collecting electrodes 2 of the row 1, which are thus caused to vibrate, whereupon the dust layer is loosened by the vibrations. The dust particles then fall into a collecting hopper (not shown) pertaining to the respective precipitation fields. The illustrated device further comprises control means which consist of upper and lower control elements for controlling the motion of each row 1 of collecting elec¬trodes in the transverse as well as longitudinal direction of the electrostatic preci¬pitator. In order to prevent, during the cleaning operation, flashover because of the motion of the row 1 in the transverse direction of the electrostatic precipitator, the U-beam 3 is provided with upper control elements in the form of upper cam control elements 11a, lib, which at each end of the U-beam 3 cooperate with the web there¬of The upper cam control elements 11a, lib also constitute a certain control of the carrier element , and thus the row, in the longitudinal direction of the electrostatic precipitator, especially at small angles a. In the embodiment illustrated. the upper cam control elements 11a, lib extend horizontally through a plurality of rows in the transverse direction of the electrostatic precipitator. In the embodiment illustrated, the lower ends of the collecting electrodes 2 are for each row loosely controlled in the longitudinal as well as transverse direction of the electrostatic precipitator by means of lower control elements, which will appear from the following description. As shown in Figs 1 and 2, the lower ends of the collecting electrodes are inserted between a pair of rods in the form of flat iron rods 12a, 12b horizontally oriented in the longitudinal direction. In this manner, the flat iron rods prevent the motion of the collecting electrodes 2 in the transverse direction of the electrostatic precipitator. The control of the collecting electrodes 2 in the longitudinal direction of the electrostatic precipitator is carried out by means of spacer members 13 arranged before, after and between the collecting electrodes 2. The spacer members 13 are fixedly mounted in the transverse direction across the rods 12a, 12b as shown in Fig. 3. Moreover, the row 1 of collecting electrodes is controlled in the transverse direction of the electrostatic precipitator by means of guiding means 14a, 14b which are vertically oriented in the transverse direction and arranged at the ends of said pairs of rods which guides the rods 12a, 12b in the longitudinal direction. The rods 12a, 12b are further provided with a supporting suspension 15 in the centre of the row 1. The control described above is designed with regard to thermal expansion. The distance between the pair of rods is fixed by spacer members (not shown), which in suitable positions are arranged between the rods. The invention is, of course, not restricted to the embodiments described above and can be modified in various ways within the scope of the appended claims. For instance, the lower ends of the collecting electrodes 2 can be firmly controlled instead of loosely controlled. For instance, the anvil 9 can be designed so as to extend across at least two successive parallel rows 1 of collecting electrodes 2 in the transverse direction of the electrostatic precipitator, instead of across a single row. WE CLAIM; 1. An electrostatic precipitator with a crevice for the suspending, guiding and rapping of cuie or more collecting electrodes (2) located essentially vertically in one or more substantially parallel rows (1) said device comprising for each row (1) a substantially horizontally oriented carrier element (3) to which the uppar ends of the collecting electrodes (2) are attached, connecting elements which connect the carrier element (3) to the casing (5) of the electrostatic precipitator, guiding means (1 la, 1 lb, 12a, 12b, 13,14a, 14b) for Riding the motion of each row (1) of collecting electrodes (2) in a transverse and/or a longitudinal direction of the electrostatic precipitator, and a rapping mechanism (6) for rapping the collecting electrodes (2), diaracterised in that the carrier element (3) of each row is separately suspended by means of said connecting elements, that the connecting elements of the carrier element (3) comprise two elongate rods (4a, 4b), each making an angle (a), relative to a vertical axis (V) extending through each rod, in the range of about 5-35 ' in such a manner that said rods (4a, 4b) are positioned substantially in the plane of the row (1) such tilt the distance between their lower ends is smaller than the distance bateau their upper ends thereby permitting, during rapping, a minimum, horizontal pivoting motion restricted to each row (1) of collecting electrodes (2) in the longitudinal direction of the electrostatic precipitator. 2. An electrostatic precipitator with a device for the suspending, guiding and rapping of one or more collecting electrodes substantially as herein described with reference to the accompanying drawings.

Full Text

The present invention relates to a device in an electrostatic precipitator for the sus¬pending, controlling and rapping of one or more collecting electrodes arranged essen¬tially vertically in one or more substantially parallel rows and comprising for each row a substantially horizontally oriented carrier element to which the upper ends of the collecting electrodes are attached, connecting elements which connect the carrier element to the casing of the electrostatic precipitator, control means for controlling the motion of each row of collecting electrodes in the transverse and/or longitudinal direction of the electrostatic precipitator, and a rapping mechanism for rapping the collecting electrodes of each row and comprising a rapping means, such as a rapping hammer, arid an anvil compelled to the carrier element.
Electrostatic precipitators are usually composed of a plurality)' of successive precipi¬tation fiends through which dust-laden gas is passed to be cleaned. Each of the preci¬pitation fields is divided into a plurality of parallel gas passages by means of a plura¬lity of juxtaposed, earthed collecting escaroles vertically arranged in rows . These are usually in the form of rectangular, substantially plate-slumped, sex-tonal metal sheets. Vertical discharge electrodes, to which a negative volute is supplied, are arranged in each gas passage. Owing to corona discharges at the discharge electrodes, the dust-laden gas is ionised in the electric field in the gas passages. The negative ions are attracted by the collecting electrodes and, while moving towards these, collide with the dust particles of the gas, which are then charged and separated from the gas by being attracted by the closest collecting electrode, on which they are deposited and build up a dust layer. At regular intervals, the dust layer is loosened, by vibrations, from the collecting electrodes by these being mechanically affected by means of a rapping mechanism. The dust particles then fall into a collecting hopper associated with the respective fields.
The rapping mechanism can either be arranged at the top or at the bottom of each row of collecting electrodes and usually comprises a rapping hammer acting in a vertical plane about a rotary shaft which extends horizontally-in the transverse direction of the electrostatic precipitator and to which the rapping hammer thus is connected, and an anvil. The rapping force for cleaning each row of collecting electrodes is generated ■

by the rapping hammer giving a horizontally directed rap via the anvil to a rapping means cooperating with the collecting electrodes, whereby a horizontal motion is imparted to the rapping means. This motion is transferred to the collecting electrodes in the form of a shock wave which spreads across these. Thus, the dust layer accumu¬lated on the collecting electrodes is loosened.
A greater or smaller amount of the rapping force is absorbed by the suspension of the collecting electrodes during the cleaning operation. The amount of absorbed rapping force depends on the manner of connecting the collecting electrodes to the suspension and on the manner in which the suspension is connected to the casing of the electro¬static precipitator.
The collecting electrodes are usually controlled in the longitudinal as well as in the transverse direction of the electrostatic precipitator so as to be kept m exact positions and, thus, prevent tlashovers.
There have been suggested various solutions of 3 in an electrostatic precipita¬tor for the suspending, controlling and rapping of its coalescing electrodes.
For instance, EP 0 584 880 discloses a device for cleaning collecting electrodes in an electrostatic precipitator by rapping, the collecting electrodes being vertically arrang¬ed, successively in parallel rows. The collecting electrodes of each rows are, at their upper ends, attached between a pair of horizontally arranged longitudinal rapping beams and suspended from these, said.beams thus also serving as earner elements for the collecting electrodes. The rapping beams rest freely on a pair of supporting beams, between which the upper ends of the collecting electrodes are arranged. The pair of supporting beams rests, in turn, on a frame pertaining to the casing of the electrostatic precipitator. The pair of rapping beams thus is atoned so as to be able to slide, during rapping, horizontally on the supporting beams in the longitudinal direction of the electrostatic precipitator. During cleaning by rapping, the rapping force is transfer¬red in the form of a shock wave by means of a rapping hammer to ail the collecting electrodes of a row via an anvil, which is fixedly mounted on the pair of rapping beams of each row. On each side of the ends of the pair of rapping beams, laminated springs are mounted in the casing and cooperate why transverse so-called stop pins arranged at each end of the pair of rapping beams. A spring-back motion of the pair .of rapping beams to its original positioning is pnnted in connection vat the rapping before the anvil is again hit by the rapping hammer. As a result, the laminated springs

control the row of collecting electrodes in the longitudinal direction of the electrosta¬tic precipitator. The laminated springs also serve as control means in the transverse direction of the electrostatic precipitator. A drawback of the thus disclosed device is that a relatively great amount of the rapping force is absorbed by the casing during rapping and, thus, is lost. Besides, for each row of collecting electrodes, the device consists of a large number of components, which makes it mechanically complicated.
The mounting of the respective rows is carried out in such a manner that the upper ends of the collecting electrodes are first inserted between the pair of the supporting beams and are temporarily mounted therein by means of bolts. Each rapping beam is then arranged on both sides of the upwardly extending ends of the collecting elec¬trodes and is mounted therein by means of bolts, whereupon the bolts in the pair of supporting beams are removed. The mounting procedure accomplished in this manner thus is complicated and time- of each row will probably also take place inside the electrostatic precipitator, which is a drawback compared with the technique of mounting the row outside the electrostatic precipitator so as to be inserted afterwards.
One object of the present invention thus is, in view of that stated above, to provide a new and improved device in an electrostatic precipitator for suspending, controlling and rapping its collecting electrodes-,-said device allowing a more efficient use of the generated rapping force when clearing the collecting electrodes. A further object of the present invention is to provide a device for suspending, controlling and rapping, which is mechanically simpler and, consequently,' easier to mount.
These objects are achieved by a device which is of the type stated b>- way of introduc¬tion and which according to the present invention is characterised in that the carrier element of each row is suspended separately by means of connecting elements, which as stated above connect the carrier element to the casing of the electrostatic precipita¬tor, thereby permitting a minimum horizontal pivoting motion restricted to each col¬lecting electrode row and occurring in the longitudinal direction of the electrostatic precipitator. The pivoting motion arising in rapping occurs owing to the separate sus¬pension and thus fully independently of the remaining rows. By a restricted, minimum pivot motion is meant a pivoting motion which is less lain about 5 mm of the carrier element in its longitudinal direction.

According to the present invention, the connecting elements of the carrier element preferably comprise two elongate rods, each making an angle a, relative to a vertical axis extending through each rod, in the range of about 5-35°, especially in the range of about 5-15°, in such a manner that said rods are positioned substantially in the plane of the row such that the distance between their lower ends is smaller than between their upper ends. In consequence of the carrier element being separately suspended in the above-mentioned fashion, the row of collecting electrodes will be self-centered after rapping, i.e. the row will immediately return to its correct original position.
The smaller the angle a the more movable the actual suspension, which means that a greater amount of the rapping force, relatively seen, will be absorbed by the casing, which results in poorer cleaning. On the other hand, the greater the angle CL the more unresilient the suspension, which also results in poorer cleaning. To achieve optometry cleaning, i.e. to transfer as great an amount as positive of the rapping force to the col¬lecting electrodes, the angle is adjxisted according to the present invention so that as small an amount as possible of the rapping force is absorbed by the casing. Moreover, the angle a should be adjusted so as to prevent too great a pivoting motion of the col¬lecting electrodes. By such suspension, which is mechanically simple and easy to mount, a more efficient cleaning of the collecting electrodes is provided.
According to the present invention, the control means of the device consist of upper control elements cooperating with the carrier element, and/or lower control elements cooperating with the lower ends of the collecting electrodes. The upper control ele¬ments preferably consist of upper cam control elements cooperating with the end por¬tions of the carrier element. Advantageously, the cam control elements extend sub¬stantially horizontally in the transverse direction of the electrostatic precipitator through a plurality of rows and thus prevent each row of collecting electrodes from moving in said direction. The upper control elements also serve as control means in the longitudinal direction of the electrostatic precipitator, especially m case of small angles a. By means of these upper control elements, which are mechanically simple and easy to mount, efficient control is achieved.
To further improve the control, in addition to the control provided by means of the _upper control elements, lower control elements are preferably arranged at the bottom

According to a preferred embodiment of the inventive device, the lower ends of the collecting electrodes are loosely controlled by the lower control elements on the one hand in the transverse direction of the electrostatic precipitator by means of a longi¬tudinally oriented, horizontal pair of rods, between which the lower ends of the col¬lecting electrodes are arranged and, on the other hand, in the longitudinal direction of the electrostatic precipitator by means of spacer members arranged before, after and/or between the collecting electrodes.
A further alternative preferred embodiment of the inventive device is characterised in that the lower ends of the collecting electrodes are firmly controlled by the lower con¬trol elements in the transverse as well as longitudinal direction of the electric preci¬pitator by means of longitudinally oriented, horizontal rods, to which the lower ends of the collecting electrodes are attached, preverbal by means of bolts or rivets.
A common feature of the lower control is teat. each row of collecting electrodes is controlled in the transverse direction of the electrostatics precipitator by means of transversely oriented lower cam control the ends of said rods. The cam control elements advantageously extend substantially vertically in the transverse direction of the electrostatic precipitator through a number of rows and thus prevent the respective rows of collecting elect codes from in said direc¬tion. By means of these lower control elements, which are mechanically simple and easy to mount, efficient control is achieved. The lower and the upper control accord¬ing to the invention is further designed with regard to thermal expansion.
According to the present invention, the anvil of the rapping mechanism is preferably directly fixedly mounted on the upper side of the cannier element and comprises a rap¬ping shoulder, which is the rapping point of the rapping means, whirly is arranged in such a manner that the rapping point is located above the horizontal centre line of the carrier element. According to an alternative embodiment, the anvil can also extend across at least two rows of collecting electrodes in the transverse direction of the elec¬trostatic precipitator. In this case, the anvil, which consists of e.g. a flat iron bar, is also directly fixedly mounted on the upper side of the carrier element of each row.
The rapping means of the rappingmechaiusm preferably acts in a vertical plane about a rotary shaft connected thereto and extending horizontally in the transverse direction of the electric precipitator, the rapping means giving the anvil a horizontally directed

rap during rapping. In on the embodiment, the rap is given to the anvil either directly or indirectly via the above-mentioned rapping shoulder.
A general advantage of the inventive device is that each row of collecting electrodes can be mounted outside the electrostatic and then be inserted.
Accordingly, the present invent movies an electrostatic precipitator with a device for the suspending, guiding and rapping of one or more collecting electrodes located essentially vertically in one or more substantially parallel rows, said device comprising for each row a substantially horizontally oriented earner element to which the upper ends of the collecting electrodes are attached, connecting elements which connect the carrier element to the casing of the electrostatic precipitator, guiding means for guiding the motion of each row of collecting electrodes in a transverse a longitudinal direction of electrostatic precipitator, and a rapping mechanism for raping the collecting electrcxles, characterised in that the carrier element of each row is separately suspended by means of said connecting elements, that the connecting elements of the carrier element comprise two elongate rods, each making an angle (a), relative to a vertical axis (V) extending through each rod, in the range of about 5-35° in such a manner that said rods are positioned substantially in the plane of the row such that the distance between their lower ends is smaller than tiie distance between their upper thereby permitting, during rapping, a minimum, horizontal pivoting motion restricted to each row of collecting electrodes in the longitudinal direction of the electrostatic precipitator.

The invention will now be described in more detail with reference to the accompany¬ing drawings, in which:
Fig. 1 is a schematic vertical section of a device according to the invention in parallel with a row of collecting electrodes in an electrostatic pre¬cipitator.
Fig. 2 is a horizontal section towards the collecting electrodes taken along line B-B in Fig. 1.
Fig. 3 is an enlarged view of a lower control element in Fig. 2.
Fig. 4 is a vertical section towards the collecting electrodes taken along line A-A in Fig. 1.
Fig. 1 thus is a schematic vertical section in parallel with a row 1 of collecting electrodes 2 in an electrostatic precipitator, which for each row 1 is provided with a device for suspending, controlling and rapping the collecting electrodes 2.
The electrostatic precipitator comprises a plurality of successive precipitation fields, each field consisting of a plurality of parallel rows 1 of earthed collecting electrodes 2, which are vertically arranged in succession in the respective rows. Each row 1 of collecting electrodes consists of substantially plate-.shaped, sectional metal sheets, which between themselves thus form gas passages for the dust-laden gas to be clean¬ed. The gas flow in the electrostatic precipitator occurs horizontally as indicated by arrow G. Between each row 1 of collecting electrodes 2, discharge electrodes (not shown) are accommodated, which are connected to a negative voltage.
As indicated in Fig. 1, the collecting electrodes 2 of each row are at their upper ends attached by means of rivets or bolts to a horizontally oriented, flexural rigid earner element in the form of a U-beam 3. The U-beam 3 is in turn separately and movably suspended by means of connecting elements, which in the embodiment illustrated consist of two inclined, elongate round bars 4a, 4b. The round bars 4a, 4b are posi¬tioned in the plane of the row and are oriented in such a manner that their lower ends

face each other and make an angle a of about 10° relative to a vertical axis V extend¬ing through the respective round bars. The lower ends of the round bars 4a, 4b are secured to the end portions of the U-beam 3 in the upper flange thereof, and the upper ends of the round bars are secured to the casing 5. Because of this, according to the invention, special suspension of the U-beam 3 and the fact that the collecting elec¬trodes 2 are in direct contact with the U-beam 3, a very small amount of the rapping force is absorbed by the casing 5, which results in efficient cleaning. Besides, the horizontal pivoting motion of the row 1 of collecting electrodes arising during clean¬ing will be minimal.
In the illustrated embodiment, the rapping mechanism 6 for cleaning the collecting electrodes 2 of each row is arranged in the centre of the U-beam 3 and comprises a rapping hammer 7, which acts in a vertical plane about a rotary shaft 8 extending horizontally in the transverse direction of the electrostatic precipitator, and an anvil 9. As shown in Fig. 1, the anvil 9 in the form of an L-beam is directly fixedly mounted by means of bolts on the upper side of tile U-beam 3 and comprises a rapping shoul¬der 10. The U-beam 3 thus serves as carrier element as well as rapping means for tile collecting electrodes 2. During cleaning, the U-beam 3 is subjected to a horizontany directed rapping hammer 7 giving the rapping shoulder 10 arranged on the anvil 9 a rap, which is transferred in the form of a shock wave to the collecting electrodes 2 via the carrier beam 3. The rapping point of the rapping hammer 7 thus is placed in such a manner that it is located above the horizontal centre line C of the U-beam 3, which is also evident from Fig. 4. The shock wave spreads downwards along all the collecting electrodes 2 of the row 1, which are thus caused to vibrate, whereupon the dust layer is loosened by the vibrations. The dust particles then fall into a collecting hopper (not shown) pertaining to the respective precipitation fields.
The illustrated device further comprises control means which consist of upper and lower control elements for controlling the motion of each row 1 of collecting elec¬trodes in the transverse as well as longitudinal direction of the electrostatic preci¬pitator. In order to prevent, during the cleaning operation, flashover because of the motion of the row 1 in the transverse direction of the electrostatic precipitator, the U-beam 3 is provided with upper control elements in the form of upper cam control elements 11a, lib, which at each end of the U-beam 3 cooperate with the web there¬of The upper cam control elements 11a, lib also constitute a certain control of the
carrier element , and thus the row, in the longitudinal direction of the
electrostatic precipitator, especially at small angles a. In the embodiment illustrated.

the upper cam control elements 11a, lib extend horizontally through a plurality of rows in the transverse direction of the electrostatic precipitator.
In the embodiment illustrated, the lower ends of the collecting electrodes 2 are for each row loosely controlled in the longitudinal as well as transverse direction of the electrostatic precipitator by means of lower control elements, which will appear from the following description.
As shown in Figs 1 and 2, the lower ends of the collecting electrodes are inserted between a pair of rods in the form of flat iron rods 12a, 12b horizontally oriented in the longitudinal direction. In this manner, the flat iron rods prevent the motion of the collecting electrodes 2 in the transverse direction of the electrostatic precipitator. The control of the collecting electrodes 2 in the longitudinal direction of the electrostatic precipitator is carried out by means of spacer members 13 arranged before, after and between the collecting electrodes 2. The spacer members 13 are fixedly mounted in the transverse direction across the rods 12a, 12b as shown in Fig. 3. Moreover, the row 1 of collecting electrodes is controlled in the transverse direction of the electrostatic precipitator by means of guiding means 14a, 14b which are vertically oriented in the transverse direction and arranged at the ends of said pairs of rods which guides the rods 12a, 12b in the longitudinal direction. The rods 12a, 12b are further provided with a supporting suspension 15 in the centre of the row 1. The control described above is designed with regard to thermal expansion. The distance between the pair of rods is fixed by spacer members (not shown), which in suitable positions are arranged between the rods.
The invention is, of course, not restricted to the embodiments described above and can be modified in various ways within the scope of the appended claims.
For instance, the lower ends of the collecting electrodes 2 can be firmly controlled instead of loosely controlled.
For instance, the anvil 9 can be designed so as to extend across at least two successive parallel rows 1 of collecting electrodes 2 in the transverse direction of the electrostatic precipitator, instead of across a single row.

WE CLAIM;
1. An electrostatic precipitator with a crevice for the suspending, guiding and
rapping of cuie or more collecting electrodes (2) located essentially vertically in one or
more substantially parallel rows (1) said device comprising for each row (1) a
substantially horizontally oriented carrier element (3) to which the uppar ends of the
collecting electrodes (2) are attached, connecting elements which connect the carrier
element (3) to the casing (5) of the electrostatic precipitator, guiding means (1 la, 1 lb,
12a, 12b, 13,14a, 14b) for Riding the motion of each row (1) of collecting electrodes
(2) in a transverse and/or a longitudinal direction of the electrostatic precipitator, and a
rapping mechanism (6) for rapping the collecting electrodes (2), diaracterised in that
the carrier element (3) of each row is separately suspended by means of said
connecting elements, that the connecting elements of the carrier element (3) comprise
two elongate rods (4a, 4b), each making an angle (a), relative to a vertical axis (V)
extending through each rod, in the range of about 5-35 ' in such a manner that said rods
(4a, 4b) are positioned substantially in the plane of the row (1) such tilt the distance
between their lower ends is smaller than the distance bateau their upper ends thereby
permitting, during rapping, a minimum, horizontal pivoting motion restricted to each
row (1) of collecting electrodes (2) in the longitudinal direction of the electrostatic
precipitator.
2. An electrostatic precipitator with a device for the suspending, guiding and
rapping of one or more collecting electrodes substantially as herein described with
reference to the accompanying drawings.

Documents:

869-mas-1996 others.pdf

869-mas-1996 abstract.pdf

869-mas-1996 claims.pdf

869-mas-1996 correspondence others.pdf

869-mas-1996 correspondence po.pdf

869-mas-1996 description (complete).pdf

869-mas-1996 drawing.pdf

869-mas-1996 form-2.pdf

869-mas-1996 form-26.pdf

869-mas-1996 form-4.pdf

869-mas-1996 form-6.pdf

869-mas-1996 petition.pdf

« Previous Patent

Next Patent »

Patent Number

194250

Indian Patent Application Number

869/MAS/1996

PG Journal Number

08/2007

Publication Date

23-Feb-2007

Grant Date

05-Jan-2006

Date of Filing

22-May-1996

Name of Patentee

ABB FLAKT AKTIEBOLAG

Applicant Address

SICKLA ALLE 13 NACKA, S-120 86 STOCKHOLM,

Inventors:

#	Inventor's Name	Inventor's Address
1	FILIP KNUTSSON	SVANVAGEN 34, S-352 42 VAXJO,

PCT International Classification Number

B03C3/86

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	9502246 - 3	1995-06-20	Sweden