CA1129788A - Rapping apparatus for an electrostatic precipitator - Google Patents
Rapping apparatus for an electrostatic precipitatorInfo
- Publication number
- CA1129788A CA1129788A CA337,336A CA337336A CA1129788A CA 1129788 A CA1129788 A CA 1129788A CA 337336 A CA337336 A CA 337336A CA 1129788 A CA1129788 A CA 1129788A
- Authority
- CA
- Canada
- Prior art keywords
- plate
- free
- hammer
- fall
- shaft
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
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- Electrostatic Separation (AREA)
Abstract
RAPPING APPARATUS FOR AN ELECTROSTATIC PRECIPITATOR
Abstract of the Disclosure A rapper for an electrostatic precipitator of the type using plate electrodes and having a free-fall hammer fastened eccentrically to a rotating shaft. The free-fall of the hammer is intercepted by an attenuator plate which is adjustable. This provides means for adjusting the force of impact on an anvil for the purpose of adjusting the rapping force during operation of the precipitator.
Abstract of the Disclosure A rapper for an electrostatic precipitator of the type using plate electrodes and having a free-fall hammer fastened eccentrically to a rotating shaft. The free-fall of the hammer is intercepted by an attenuator plate which is adjustable. This provides means for adjusting the force of impact on an anvil for the purpose of adjusting the rapping force during operation of the precipitator.
Description
~z~
RAPPING APPARATUS FOR AN ELECTROSTATIC PRECIPITATOR
Background of the Invention The invention relates to electrostatic precipitators and in particular to a rapping mechanism therefore.
During operation of electrostatic precipitators dust collects on the electrodes. In order to maintain a high dust collection efficiency, the dust must be periodically removed from the electrodes. One method of removing this dust is rapping the electrodes to shake the dust free.
A simple low maintenance apparatus for effecting this rapping involves locating anvils which contact selected collector plates. A hammer is eccentrically located to a rotating shaft such ; that it is raised above the shaft during the rotation. As it passes top dead center, the hammer swings free under the force of gravity and strikes the anvil.
It is essential to rap the electrodes with sufficient force to break the dust loose. Preferably the dust breaks loose from the electrodes in flakes dropping to the hopper located there-below. If excessive rapping force is used, the flakes are disin-tegrated reforming as dust which is then carried on through the prec;pitator with the gas. Other rapping mechanisms such as electro-magnetic coils which shake an entire electrode field have been designed with varying rapping intensity so that the optimum rapping intensity for a particular precipitator can be obtained.
Adjusting the rapping intensity of free-fall hammers requires shutting down the apparatus and changing the hammers. This is inconvenient and costly because of the many shutdowns and the difficulty of predicting the rapping performance under particular C780Y90 operating conditions. Furthermore should operating conditions -.
~L~lZ~37 ~3 change, a shutdown is required for modification of the rapping intensity.
In addition to the problem of disintegration of the flakes when rapping with unnecessary force, the excess force creates unnecessary wear and tear on the equipment.
In Russian Patent No. 450,592 a plate is arranged passing within the normal free fall path of a rapping hammer.
The plate is pivoted above the top position of the hammer, and is movable to various locations, each cutting a sector thru the free fall path.
'~lith such an arrangement the plate must also intercept the path of the hammer in its fully cocked position. It must, therefore, move with each rotation of the hammer. If the plate is spring loaded it can limit the minimum hammer fall only from the position where the hammer and plate are perpendicular, re~ardless of the initial plate position. Alternately -the plate must be independently actuated to release the hammer from some point between its initial contact point and the limit position clescribed above. Such an apparatus involves wear, restricted adjustment flexibility, and/or complicated operating mechanism.
Summary of the Invention It is an object of the invention to vary the rapping intenstty of a free-fall hammer-type rapper in a simple manner which may be effectuated without shutting down the equipment.
The electrostatic precipitator of the invention is of the type using suspended plate-shaped electrodes and including an anv;l which is rapped to remove the dust from the electrodes. A
free-fall hammer associated with each of the rapping bars is attached to a rotating shaft so that it falls against the anvil ~0 from the top dead center position, with the weight and size being selected to obtain the maximum desired rapping intensity with this free-fall. An attenuator plate is adjustably located to a fixed position within this free-fall area of the hammer so that the hammer is intercepted during its fall by the attenuator plate. The subse-quent fall from the attenuator plate to the anvil is adjusted bylocating the attenuator plate. The attenuator plate may be adjusted :780990 from outside the apparatus, thereby varying the rapping intensity of the free-fall hammer.
Brief Description of the Dra~!in~s Figure 1 is a general arrangement o-f the electrostatic precipitator, Figure 2 is a detail view of the anvil beam hammer and attenuator plate, and Figure 3 is a plan view of the impact area of the anvil illustrating several hammers.
Description o~ the Preferred Embodiment A casing 10 is arranged to confine a flow of gases 12 passing horizontally through the precipitator. A plurality of plate-shaped collector electrodes 14 are each pivotally suspended from pins 16 and aligned so as to be parallel with the flow of gases. A plurality of these electrodes are arranged in a plurality of transverse parallel rows.
A plurality of anvil beams 18 are supported from each of the transverse rows of electrodes. They are operatively attached to the row of electrodes so that an impact on the anvil beam will be transmitted to the freely suspended collector plates for the purpose of shakiny dust therefrom. Each of the anYil beams has an impact location 20 at one end thereof.
A slowly rotating shaft 22 is located above one end of the anvil. Eccentrically attached to the shaft by pivot pin 24 is a hammer 26. As the shaft is rotated, the hammer moves to the top dead center location 28 from which upon further rotation of the shaft it falls through the free-fall zone 3n downwardly striking the anvil 1>3 at impact location 20. Operation as described provides the maximum impact for a particular size and weight hammer.
An attenuator plate 32 is mounted with an axis 34 parallel to the shaft 22 and located outside the free-fall zone 30. The attenuator plate may be anaularly adjusted to any selected position aroundits axis by moving the external adjustment arm 36 which is located outside the precipitator by extension of the axis 34.
Arcuate plate 38 has a plurality of locking points such that the 80990 external arm may be locked into any locking point, thereby setting ~L~2~38 a relative position of the attenuator plate within the apparatus.
The attenuator plate 32 is held in the locked position during day-to-day operation of the precipitator. ~Ihen it is desired that the rapping intensity be changed, the plate is moved to an alternate locked position. This change in position may be accomplished with the precipitator in operation by moving arm 36 to a new locked position with respect to plate 38.
The attenuator plate is extended inwardly from the axis 34 so that in selected locations it will pass within the free-fall zone 30. In such a location, the attenuator plate will intercept the free-fall of the hammer. As the shaft 22 is further rotated and pin 24 moves away from the attenuator plate, the head 40 of the hammer pulls free from the attenuator plate and falls against the anvil with reduced force.
lS The attenuator plate may be of any shape or form provided only that it intersect the free-fall path to intercept the fall of the hammer. It may extend further into the free-fall zone than illustrated if more adjustab;lity is required. Locatins the atten-uator plate with free space between it and the shaft prcvides means for the hammer to pull free from the attenuator plate so that it may impact with the reduced force.
It can be seen, upon inspection of Figure 2, that release of the hammer from attenuator plate 32 is caused by the rotation of shaft 22 carrying pin 24 away from plate 32. The plate must be located so that the head 40 clears the plate before shaft 22 binds the hammer 26. The bindin~ position is the relative position between hammer 26 and shaft 22 illustrated as the cocked position at the top dead center location 28. More specifically~ the distance between the centerline of shaft 22 and the closest portion of attenuator plate 32 must be greater than the distance between the centerline and the outer edge of hammer ao when it is at the top dead center location 28.
As best seen in Figure 3, the attenuator plate extends across a number of the transverse parallel rows to intersect with the free-fall hammers of each line of electrodes. These hammers are conventionally located at different positions around the shaft so C7809gO
~l~2~7~!3 that the timing of the impacts on the anvil as well as the attenuator plate are stagqered.
sasso
RAPPING APPARATUS FOR AN ELECTROSTATIC PRECIPITATOR
Background of the Invention The invention relates to electrostatic precipitators and in particular to a rapping mechanism therefore.
During operation of electrostatic precipitators dust collects on the electrodes. In order to maintain a high dust collection efficiency, the dust must be periodically removed from the electrodes. One method of removing this dust is rapping the electrodes to shake the dust free.
A simple low maintenance apparatus for effecting this rapping involves locating anvils which contact selected collector plates. A hammer is eccentrically located to a rotating shaft such ; that it is raised above the shaft during the rotation. As it passes top dead center, the hammer swings free under the force of gravity and strikes the anvil.
It is essential to rap the electrodes with sufficient force to break the dust loose. Preferably the dust breaks loose from the electrodes in flakes dropping to the hopper located there-below. If excessive rapping force is used, the flakes are disin-tegrated reforming as dust which is then carried on through the prec;pitator with the gas. Other rapping mechanisms such as electro-magnetic coils which shake an entire electrode field have been designed with varying rapping intensity so that the optimum rapping intensity for a particular precipitator can be obtained.
Adjusting the rapping intensity of free-fall hammers requires shutting down the apparatus and changing the hammers. This is inconvenient and costly because of the many shutdowns and the difficulty of predicting the rapping performance under particular C780Y90 operating conditions. Furthermore should operating conditions -.
~L~lZ~37 ~3 change, a shutdown is required for modification of the rapping intensity.
In addition to the problem of disintegration of the flakes when rapping with unnecessary force, the excess force creates unnecessary wear and tear on the equipment.
In Russian Patent No. 450,592 a plate is arranged passing within the normal free fall path of a rapping hammer.
The plate is pivoted above the top position of the hammer, and is movable to various locations, each cutting a sector thru the free fall path.
'~lith such an arrangement the plate must also intercept the path of the hammer in its fully cocked position. It must, therefore, move with each rotation of the hammer. If the plate is spring loaded it can limit the minimum hammer fall only from the position where the hammer and plate are perpendicular, re~ardless of the initial plate position. Alternately -the plate must be independently actuated to release the hammer from some point between its initial contact point and the limit position clescribed above. Such an apparatus involves wear, restricted adjustment flexibility, and/or complicated operating mechanism.
Summary of the Invention It is an object of the invention to vary the rapping intenstty of a free-fall hammer-type rapper in a simple manner which may be effectuated without shutting down the equipment.
The electrostatic precipitator of the invention is of the type using suspended plate-shaped electrodes and including an anv;l which is rapped to remove the dust from the electrodes. A
free-fall hammer associated with each of the rapping bars is attached to a rotating shaft so that it falls against the anvil ~0 from the top dead center position, with the weight and size being selected to obtain the maximum desired rapping intensity with this free-fall. An attenuator plate is adjustably located to a fixed position within this free-fall area of the hammer so that the hammer is intercepted during its fall by the attenuator plate. The subse-quent fall from the attenuator plate to the anvil is adjusted bylocating the attenuator plate. The attenuator plate may be adjusted :780990 from outside the apparatus, thereby varying the rapping intensity of the free-fall hammer.
Brief Description of the Dra~!in~s Figure 1 is a general arrangement o-f the electrostatic precipitator, Figure 2 is a detail view of the anvil beam hammer and attenuator plate, and Figure 3 is a plan view of the impact area of the anvil illustrating several hammers.
Description o~ the Preferred Embodiment A casing 10 is arranged to confine a flow of gases 12 passing horizontally through the precipitator. A plurality of plate-shaped collector electrodes 14 are each pivotally suspended from pins 16 and aligned so as to be parallel with the flow of gases. A plurality of these electrodes are arranged in a plurality of transverse parallel rows.
A plurality of anvil beams 18 are supported from each of the transverse rows of electrodes. They are operatively attached to the row of electrodes so that an impact on the anvil beam will be transmitted to the freely suspended collector plates for the purpose of shakiny dust therefrom. Each of the anYil beams has an impact location 20 at one end thereof.
A slowly rotating shaft 22 is located above one end of the anvil. Eccentrically attached to the shaft by pivot pin 24 is a hammer 26. As the shaft is rotated, the hammer moves to the top dead center location 28 from which upon further rotation of the shaft it falls through the free-fall zone 3n downwardly striking the anvil 1>3 at impact location 20. Operation as described provides the maximum impact for a particular size and weight hammer.
An attenuator plate 32 is mounted with an axis 34 parallel to the shaft 22 and located outside the free-fall zone 30. The attenuator plate may be anaularly adjusted to any selected position aroundits axis by moving the external adjustment arm 36 which is located outside the precipitator by extension of the axis 34.
Arcuate plate 38 has a plurality of locking points such that the 80990 external arm may be locked into any locking point, thereby setting ~L~2~38 a relative position of the attenuator plate within the apparatus.
The attenuator plate 32 is held in the locked position during day-to-day operation of the precipitator. ~Ihen it is desired that the rapping intensity be changed, the plate is moved to an alternate locked position. This change in position may be accomplished with the precipitator in operation by moving arm 36 to a new locked position with respect to plate 38.
The attenuator plate is extended inwardly from the axis 34 so that in selected locations it will pass within the free-fall zone 30. In such a location, the attenuator plate will intercept the free-fall of the hammer. As the shaft 22 is further rotated and pin 24 moves away from the attenuator plate, the head 40 of the hammer pulls free from the attenuator plate and falls against the anvil with reduced force.
lS The attenuator plate may be of any shape or form provided only that it intersect the free-fall path to intercept the fall of the hammer. It may extend further into the free-fall zone than illustrated if more adjustab;lity is required. Locatins the atten-uator plate with free space between it and the shaft prcvides means for the hammer to pull free from the attenuator plate so that it may impact with the reduced force.
It can be seen, upon inspection of Figure 2, that release of the hammer from attenuator plate 32 is caused by the rotation of shaft 22 carrying pin 24 away from plate 32. The plate must be located so that the head 40 clears the plate before shaft 22 binds the hammer 26. The bindin~ position is the relative position between hammer 26 and shaft 22 illustrated as the cocked position at the top dead center location 28. More specifically~ the distance between the centerline of shaft 22 and the closest portion of attenuator plate 32 must be greater than the distance between the centerline and the outer edge of hammer ao when it is at the top dead center location 28.
As best seen in Figure 3, the attenuator plate extends across a number of the transverse parallel rows to intersect with the free-fall hammers of each line of electrodes. These hammers are conventionally located at different positions around the shaft so C7809gO
~l~2~7~!3 that the timing of the impacts on the anvil as well as the attenuator plate are stagqered.
sasso
Claims (3)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A rapping apparatus for an electrostatic precipitator having a casing for conveying a horizontal flow of gas to be cleaned, a plurality of plate-shaped collecting electrodes arranged parallel to the gas flow direction and located in transverse paral-lel rows, means for pivotally suspending said electrodes, and elon-gated anvils connected to each row of said transverse rows of elec-trodes, comprising: a rotatable shaft located above one end of said anvils; a pivot located on said rotatable shaft at a location eccentric of the centerline of said shaft; hammers pivotally sup-ported on said pivot and arranged for free-fall from top dead center to an impact point against each of said anvils; and an atten-uator plate adjustably located in the free-fall path of each of said hammers, said attenuator plate being rigid and located with sufficient free space between said attenuator plate and said rota-table shaft such that continued rotation of the shaft past the free-fall position causes the hammer to be released from the rigid atten-uator plate.
2. An apparatus as in claim 1, wherein said attenuator plate is angularly adjustable about an axis parallel to said shaft, with said axis being at a location outside the free-fall area, said plate extending into said free-fall area at varying fixed locations, and being adjustable by location of the plate around its axis.
3. An apparatus as in claim 1 or 2, wherein the distance bet-ween the centerline of said rotatable shaft and the closest portion of said attenuator plate is greater than the distance from the centerline of said rotatable shaft and the outer edge of each hammer when each hammer is at the top dead center position.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US95902978A | 1978-11-08 | 1978-11-08 | |
| US959,029 | 1978-11-08 | ||
| US42084579A | 1979-09-17 | 1979-09-17 | |
| US420,845 | 1979-09-17 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1129788A true CA1129788A (en) | 1982-08-17 |
Family
ID=27025004
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA337,336A Expired CA1129788A (en) | 1978-11-08 | 1979-10-10 | Rapping apparatus for an electrostatic precipitator |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1129788A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7459010B2 (en) | 2005-02-10 | 2008-12-02 | Alstom Technology Ltd | Method and apparatus for the acceleration of an electromagnetic rapper |
| CN102350099A (en) * | 2011-06-23 | 2012-02-15 | 韦志锋 | Oscillatory type sewage sedimentation basin and operation method thereof |
-
1979
- 1979-10-10 CA CA337,336A patent/CA1129788A/en not_active Expired
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7459010B2 (en) | 2005-02-10 | 2008-12-02 | Alstom Technology Ltd | Method and apparatus for the acceleration of an electromagnetic rapper |
| CN102350099A (en) * | 2011-06-23 | 2012-02-15 | 韦志锋 | Oscillatory type sewage sedimentation basin and operation method thereof |
| CN102350099B (en) * | 2011-06-23 | 2015-05-20 | 韦志锋 | Oscillatory type sewage sedimentation basin and operation method thereof |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |