CA1045051A - Gravel bed dust collector - Google Patents
Gravel bed dust collectorInfo
- Publication number
- CA1045051A CA1045051A CA224,229A CA224229A CA1045051A CA 1045051 A CA1045051 A CA 1045051A CA 224229 A CA224229 A CA 224229A CA 1045051 A CA1045051 A CA 1045051A
- Authority
- CA
- Canada
- Prior art keywords
- duct
- back flush
- gas
- gas duct
- dust collector
- 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
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D46/00—Filters or filtering processes specially modified for separating dispersed particles from gases or vapours
- B01D46/30—Particle separators, e.g. dust precipitators, using loose filtering material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2273/00—Operation of filters specially adapted for separating dispersed particles from gases or vapours
- B01D2273/20—High temperature filtration
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Filtering Of Dispersed Particles In Gases (AREA)
- Cyclones (AREA)
Abstract
Abstract A gravel bed dust collector system is arranged so that each of a number of gravel beds may be individually back flushed by a single back flush collector and fan combination. Preferably the ducts carrying dust laden raw gas or back flush gas from the filter beds are arranged vertically to inhibit settling of dust in the ducts. It is also preferable, although not necessary, to operate the collection system and the back flush recirculation system under negative pressure in order to minimize gas leaks to the environment.
Description
Background of the Invention ~arious types o~ systems for separating solid particles of material, such as dust from gas from a boiler, industrial process, or similar sources, are in use. If 5the temperature of the gas carrying the dust is low enough the gas may be passed through porous filter bags or through a spray chamber in which a liquid spray separates the dust from the gas. If the gas is hot these systems are not suitable 5 because of the danger of fire or rapid evaporation of the lQspray materials.
Gravel bed filters have been used in high temperature systems. In a gravel bed system the raw gas (gas carrying the dust to be collected) is drawn, usually downwardly, through a bed of particulate material. The dust lodges 15on the particles of filter material. As the process continues the dust collected in the ~ilter bed impedes-the flow and the dust must then be removed. This is done by replacing the bed or by back flushing it by flowing clean air through the filter bed in a direction reverse to the previous gas 20flow while gently agitating the bed. Much of the collected dust agglomerates into a filter cake that is carried off ;
in pieces during the back ~lush operation. In the usual systems, the back flush gas at a pressure higher than the pressure of the raw gas is forced through the bed, then through a raw gas precleaner such as a cyclone for the -individual filter bed and into the raw gas duct. It is intended thak the pieces of filter cake be collected in the inlet precleaner or cyclone. However~ a separator, such as a cyclone separator, is e~ficient only for flow in one 3 direction and as a result much of the filter cake is broken ;
and dust is carried back into the raw gas duct to be collected ~,i another fllter bed. As a reault the ~ystem tends to load up wlth dust and the actual dust collectlng capacity of the system i~ reduced.
SUMMARY OF THE INVENTION
.
According to ~he invention a number of filter modules, each with a filter bed, are arranged such that a separate collector and fan, in cooperation with simple valves in the ducts of ~he system, may draw back flush gas through a selected filter bed and the collector and discharge the gas from the collector into a raw gas duct of the system. The invention further includes arranging the back flush gas supply duct of the system in heat exchange relation wi~h at least one of the raw gas duct - and cleaned gas duct to heat the back flush gas and thus avoid cooling and condensing any vapours from the raw gas that might be in the filter systems. In a preferred form of the invention the system is arranged so that at least the raw gas duct and the back flush receiver duct from the modules are substantially vertical and extend upwardly from collected dust discharge means.
Broadly speaking, therefore, the present invention ;~
provides a gravel bed dust collector system comprising in combina-tion, at least two collector modules each comprising an upper and a lower chamber, a perforated partition separating the chamber~ and a bed of particulate fileer material on the partition, a raw gas duct that receives the gas to be cleaned and that has sollds material discharge means, a back flush receiver duct tha~
extendo generally parallel to the raw ga~ duct, first branch ducts includi~g valves arran8ed to selectively connect the upper chamber of each module to the raw gas duct and the back flush receiver duct, a cleaned ga~ duct that extends generally parallsl to the raw gas duct, a back flush 8as supply duct, second branch -~ducts lncluding vslves arranged to s~lectively connect the lower chamber of each module to the cleaned gas duct and back flush gas ~upply duct, and a dust collector and fsn arranged a~d connected ,1 ~ - 2 -d ap /)~3 .. . .
. . .
;. . . . ~ :.
~LO~S~51 ln series betwee~ the back flush receiver duct and the raw gas duct, the fan servin~ to malntain the pre~sure in the back flush receiver duct less than the Pressure in the raw ~as duct, whereby, when the valves are in first positions ~as may be drawn f rom the raw gas duct, downwardly throu~h the bed of particulate -filter material and into the cleaned gas duct, and when the valves are in second positions back flush gas from the back flush gas supply duct is drawn upwardly through the filter beds and the gas together with collected dust from the bed is carried through the back flush receiver dust into the dust collector.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a schematic diagram of the improved dust collector system.
~ig. 2 is a perspective view, wîth parts broken away, `-of a filter module of the improved system.
Fig. 3 is a front elevation, with part broken away, of a preferred arrangement of filter modules and connectin~ ducts.
Fig. 4 is a side elevation, with parts broken away, of the preferred arrangement.
Fig. 5 is a top view, with parts broken away, of the preferred arrangement.
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Description of a Preferred Embodiment A gravel bed dust collecter system operates on the principle that the fine dust in the gas to be cleaned can be caught in the gravel bed of a module as the gas flows from the raw gas duct through the module to the cleaned gas duct. The collected dust serves to catch more of the dust so that a layer of dust forms on the surface of the gravel bed. The dust in this layer tends to agglomerate.
When the pressure drop for a given gas flow exceeds a given value, i.e. a substantial quantity of dust has been collected on the bed, the collected dust is removed from the bed.
This is done by back flushing the bed, i.e. drawing or blowing clean air or gas through the bed in a reverse direction. -The reverse air flow, perferably aided by gentle mechanical agitation of the bed, lifts the collected dust out of and off the bed. In accordance with the invention~ the back flush air or gas after leaving the module is drawn through a collector, preferably of the cyclone type, and discharged into the raw gas duct. A cyclone type collector can easily collect the agglomerated dust although it is quite inefficient '.~:, , !, in collecting the dust before agglomeration.
The gas flow paths in the improved dust collector system are shown in Fig. 1. As shown, the raw gas to be cleaned enters the system through a raw gas duct 1. Just before it enters an upper chamber 2 of a filter module 3 it passes a diverter valve 4 which normally is in its first position with the duct 1 open.
~ rom the upper chamber 2 the raw gas flows down through a gravel bed 5 that is supported on a perforated divider plate or partition 6 and into a lower chamber 7 of the module 3. As the raw gas is passing through the gravel bed 5 dust in the gas is trapped by the particulate material of the bed 5 while the now cleaned gas continues , , ~ ~ ; , , : , ~L~45~S~
through the bed and partition into the lower chamber 7 and out through a normally open back flush valve 8 into a cleaned gas duct 9. An induction fan 10 maintains a subatmosphere pressure in the cleaned gas duct 9 to maintain the just described gas flow. `
In a commercial system a plurality of modules 3 are provided, the raw gas duct 1 and the cleaned gas duct 9 are in fact manifolds with short branch ducts leading to the individual filter modules 3. A diverter valve 4 is ~
lQ provided in each branch duct from the raw gas duct while ~;
each branch duct from the cleaned gas duct 9 includes a back flush valve 8. :
When the bed 5 is to be back flushed the associated diverter valve 4 and back flush valve 8 are moved to their '`
second positions. Air or cleaned gas from the output of the fan 10 is then drawn from a back flush gas supply duct 11, through the back flush valve 8, the lower chamber ~;-7, the perforated partition 6 and filter bed 5 into the ~'r .:
upper chamber 2. While passing through the bed 5 the gas 2Q picks up the collected dust and carries it from the chamber .,, ,, :
Gravel bed filters have been used in high temperature systems. In a gravel bed system the raw gas (gas carrying the dust to be collected) is drawn, usually downwardly, through a bed of particulate material. The dust lodges 15on the particles of filter material. As the process continues the dust collected in the ~ilter bed impedes-the flow and the dust must then be removed. This is done by replacing the bed or by back flushing it by flowing clean air through the filter bed in a direction reverse to the previous gas 20flow while gently agitating the bed. Much of the collected dust agglomerates into a filter cake that is carried off ;
in pieces during the back ~lush operation. In the usual systems, the back flush gas at a pressure higher than the pressure of the raw gas is forced through the bed, then through a raw gas precleaner such as a cyclone for the -individual filter bed and into the raw gas duct. It is intended thak the pieces of filter cake be collected in the inlet precleaner or cyclone. However~ a separator, such as a cyclone separator, is e~ficient only for flow in one 3 direction and as a result much of the filter cake is broken ;
and dust is carried back into the raw gas duct to be collected ~,i another fllter bed. As a reault the ~ystem tends to load up wlth dust and the actual dust collectlng capacity of the system i~ reduced.
SUMMARY OF THE INVENTION
.
According to ~he invention a number of filter modules, each with a filter bed, are arranged such that a separate collector and fan, in cooperation with simple valves in the ducts of ~he system, may draw back flush gas through a selected filter bed and the collector and discharge the gas from the collector into a raw gas duct of the system. The invention further includes arranging the back flush gas supply duct of the system in heat exchange relation wi~h at least one of the raw gas duct - and cleaned gas duct to heat the back flush gas and thus avoid cooling and condensing any vapours from the raw gas that might be in the filter systems. In a preferred form of the invention the system is arranged so that at least the raw gas duct and the back flush receiver duct from the modules are substantially vertical and extend upwardly from collected dust discharge means.
Broadly speaking, therefore, the present invention ;~
provides a gravel bed dust collector system comprising in combina-tion, at least two collector modules each comprising an upper and a lower chamber, a perforated partition separating the chamber~ and a bed of particulate fileer material on the partition, a raw gas duct that receives the gas to be cleaned and that has sollds material discharge means, a back flush receiver duct tha~
extendo generally parallel to the raw ga~ duct, first branch ducts includi~g valves arran8ed to selectively connect the upper chamber of each module to the raw gas duct and the back flush receiver duct, a cleaned ga~ duct that extends generally parallsl to the raw gas duct, a back flush 8as supply duct, second branch -~ducts lncluding vslves arranged to s~lectively connect the lower chamber of each module to the cleaned gas duct and back flush gas ~upply duct, and a dust collector and fsn arranged a~d connected ,1 ~ - 2 -d ap /)~3 .. . .
. . .
;. . . . ~ :.
~LO~S~51 ln series betwee~ the back flush receiver duct and the raw gas duct, the fan servin~ to malntain the pre~sure in the back flush receiver duct less than the Pressure in the raw ~as duct, whereby, when the valves are in first positions ~as may be drawn f rom the raw gas duct, downwardly throu~h the bed of particulate -filter material and into the cleaned gas duct, and when the valves are in second positions back flush gas from the back flush gas supply duct is drawn upwardly through the filter beds and the gas together with collected dust from the bed is carried through the back flush receiver dust into the dust collector.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a schematic diagram of the improved dust collector system.
~ig. 2 is a perspective view, wîth parts broken away, `-of a filter module of the improved system.
Fig. 3 is a front elevation, with part broken away, of a preferred arrangement of filter modules and connectin~ ducts.
Fig. 4 is a side elevation, with parts broken away, of the preferred arrangement.
Fig. 5 is a top view, with parts broken away, of the preferred arrangement.
~i"
,' ,,.
, d ap /,~
:1 ,. ,~
~45~5~
Description of a Preferred Embodiment A gravel bed dust collecter system operates on the principle that the fine dust in the gas to be cleaned can be caught in the gravel bed of a module as the gas flows from the raw gas duct through the module to the cleaned gas duct. The collected dust serves to catch more of the dust so that a layer of dust forms on the surface of the gravel bed. The dust in this layer tends to agglomerate.
When the pressure drop for a given gas flow exceeds a given value, i.e. a substantial quantity of dust has been collected on the bed, the collected dust is removed from the bed.
This is done by back flushing the bed, i.e. drawing or blowing clean air or gas through the bed in a reverse direction. -The reverse air flow, perferably aided by gentle mechanical agitation of the bed, lifts the collected dust out of and off the bed. In accordance with the invention~ the back flush air or gas after leaving the module is drawn through a collector, preferably of the cyclone type, and discharged into the raw gas duct. A cyclone type collector can easily collect the agglomerated dust although it is quite inefficient '.~:, , !, in collecting the dust before agglomeration.
The gas flow paths in the improved dust collector system are shown in Fig. 1. As shown, the raw gas to be cleaned enters the system through a raw gas duct 1. Just before it enters an upper chamber 2 of a filter module 3 it passes a diverter valve 4 which normally is in its first position with the duct 1 open.
~ rom the upper chamber 2 the raw gas flows down through a gravel bed 5 that is supported on a perforated divider plate or partition 6 and into a lower chamber 7 of the module 3. As the raw gas is passing through the gravel bed 5 dust in the gas is trapped by the particulate material of the bed 5 while the now cleaned gas continues , , ~ ~ ; , , : , ~L~45~S~
through the bed and partition into the lower chamber 7 and out through a normally open back flush valve 8 into a cleaned gas duct 9. An induction fan 10 maintains a subatmosphere pressure in the cleaned gas duct 9 to maintain the just described gas flow. `
In a commercial system a plurality of modules 3 are provided, the raw gas duct 1 and the cleaned gas duct 9 are in fact manifolds with short branch ducts leading to the individual filter modules 3. A diverter valve 4 is ~
lQ provided in each branch duct from the raw gas duct while ~;
each branch duct from the cleaned gas duct 9 includes a back flush valve 8. :
When the bed 5 is to be back flushed the associated diverter valve 4 and back flush valve 8 are moved to their '`
second positions. Air or cleaned gas from the output of the fan 10 is then drawn from a back flush gas supply duct 11, through the back flush valve 8, the lower chamber ~;-7, the perforated partition 6 and filter bed 5 into the ~'r .:
upper chamber 2. While passing through the bed 5 the gas 2Q picks up the collected dust and carries it from the chamber .,, ,, :
2 through a short branch duct and the diverter valve 4 into a back flush receiver duct 12 that leads into a dust collector 13, preferably a cyclone, and thence through a back flush fan 14 that discharges into the raw gas duct 1.
While a bed is being back flushed it is gently 1" :
agitated by a motor driven rake 15 to loosen the dust adhering to the particles without breaking up or reducing the agglomerated ... .
material to dust.
It may be noted that any leakage in the diverter valve 4 merely passes raw gas from the raw gas duct 1 into the back flush receiver duct 12 from which it is returned .' .' by way of the collector 13 and fan 14 to the raw gas duct.
Thus the only effect of the leakage is to slightly increase S~Sl the load on the fan 14. Likewise any leakage through the back flush valve 8 passes clean air or gas from the back flush supply duct 11 to the cleaned gas duct 9 with no -ill effects other than a slight increase in load on the induction ran 10.
Each rilter module 3, as shown in greater detail ~
in Fig. 2, comprises a generally cylindrical tank 16 that `
i5 divided into the upper chamber 2 and lower chamber 7 by the perforated partition 6. The gravel bed 5 resting ;
on the partition 6 may be any suitable granular material, such as, for example, silica sand. During back rlush~
to loosen the collected dust, the bed 5 is gently agitated by the rake 15 having tines 17 that clear the partition 6.
The rake 15 is driven by any suitable drive such as a gear motor 18 mounted on the top of the tank or container 16.
The upper chamber 2 is connected by branch duct 19 and diverter valve 4 to either the raw gas duct 1 or the back ~lush receiver duct 12. Pre~erably the branch duct 19 is rectangular in cross section so that a simple valve plate 20 hinged at a side of the duct can alternatively close the portions 21, 22 of the duct leading to the raw gas duct 1 and receiver duct 12 respectively. Any suitable operator 23 may be provided to move the valve plate 20.
It is desirable but not necessary that the path of the back flush gas be as straight as possible to avoid fragmentation o~ the agglomerated dust loosened ~rom the filter bed.
A similar branch duct 24 connects the lower chamber 7 to the back ~lush supply duct 11 and the cleaned gas duct 9. A suitable valve plate 25 moved by an operator 26 controls .
. . .
: ,, , ~. , ;, 11)45~1S~ ~
the flow through branches 27 and 28 connected to the cleaned gas and back flush supply ducts respectively.
In a typical installation a plurality of modules
While a bed is being back flushed it is gently 1" :
agitated by a motor driven rake 15 to loosen the dust adhering to the particles without breaking up or reducing the agglomerated ... .
material to dust.
It may be noted that any leakage in the diverter valve 4 merely passes raw gas from the raw gas duct 1 into the back flush receiver duct 12 from which it is returned .' .' by way of the collector 13 and fan 14 to the raw gas duct.
Thus the only effect of the leakage is to slightly increase S~Sl the load on the fan 14. Likewise any leakage through the back flush valve 8 passes clean air or gas from the back flush supply duct 11 to the cleaned gas duct 9 with no -ill effects other than a slight increase in load on the induction ran 10.
Each rilter module 3, as shown in greater detail ~
in Fig. 2, comprises a generally cylindrical tank 16 that `
i5 divided into the upper chamber 2 and lower chamber 7 by the perforated partition 6. The gravel bed 5 resting ;
on the partition 6 may be any suitable granular material, such as, for example, silica sand. During back rlush~
to loosen the collected dust, the bed 5 is gently agitated by the rake 15 having tines 17 that clear the partition 6.
The rake 15 is driven by any suitable drive such as a gear motor 18 mounted on the top of the tank or container 16.
The upper chamber 2 is connected by branch duct 19 and diverter valve 4 to either the raw gas duct 1 or the back ~lush receiver duct 12. Pre~erably the branch duct 19 is rectangular in cross section so that a simple valve plate 20 hinged at a side of the duct can alternatively close the portions 21, 22 of the duct leading to the raw gas duct 1 and receiver duct 12 respectively. Any suitable operator 23 may be provided to move the valve plate 20.
It is desirable but not necessary that the path of the back flush gas be as straight as possible to avoid fragmentation o~ the agglomerated dust loosened ~rom the filter bed.
A similar branch duct 24 connects the lower chamber 7 to the back ~lush supply duct 11 and the cleaned gas duct 9. A suitable valve plate 25 moved by an operator 26 controls .
. . .
: ,, , ~. , ;, 11)45~1S~ ~
the flow through branches 27 and 28 connected to the cleaned gas and back flush supply ducts respectively.
In a typical installation a plurality of modules
3 are operated in parallel during the dust collecting time and are back flushed individually. That is~ while one module is being back flushed or regenerated the remaining modules are collecting dust.
A preferred arrangement for a commercial installation is shown in Fig. 3, 4 and 5. The filter modules 3 are arranged in groups, each group occupying one level or one floor of a tower arrangement. The tower comprises an open frame 30 including a horizontal support frame 31 at each level to carry the filter modules of that graoup. The modules ^;
can also be arranged in a spiral like the steps of a spiral staircase. A raw gas duct 32, corresponding to the duct -1 of Fig. 1 and shown as rectangular in cross section, extends vertically up the center of the tower. As shown, ,.,~; ~
it has an inlet 33 (Fig. 3) leading into its lower end. .
The inlet may be at any elevation depending upon the particular installation. The duct 32 has a solids discharge gate 34 at its bottom. The gate 34, which is provided with tipping valves or other suitable means forming an air lock, discharges into a solids collector conveyor 35 to dispose o~ any solids matter that may drop out of the raw gas in the raw gas duct.
At each module branch ducts, similar to the duct `~
19, 22, 23 lead from the raw gas duct 32 into the upper :
chamber of the module and from the module to a back flush receiver duct 37. Diverter valves corresponding to the valve 20 (Fig. 2) are arranged to direct the flow into the chamber as indicated by an arrow 38 ( Fig. 5) or from the chamber to the back flush receiver ducts as shown by arrow 39 ( Fig. 5).
~'04S~S~ ::
The back flush receiver duct 37, which may be either one or several individual ducts, leads into a cyclone collector 40. The output of the cyclone passes through a fan 41 and into the raw gas duct 32. When several individual 5 back flush ducts are used it may be more convenient to supply more than one cyclone collector and fan than to supply the duck work required to lead all of the ducts into one cyclone. Also the provision of two or more cyclones and fans allows an equal number of modules to be back flushed 10 simultaneously.
The cleaned gas from the lower chamber 7 of each module flows through a branch duct 42 and a back flush ~ ~ va ~e
A preferred arrangement for a commercial installation is shown in Fig. 3, 4 and 5. The filter modules 3 are arranged in groups, each group occupying one level or one floor of a tower arrangement. The tower comprises an open frame 30 including a horizontal support frame 31 at each level to carry the filter modules of that graoup. The modules ^;
can also be arranged in a spiral like the steps of a spiral staircase. A raw gas duct 32, corresponding to the duct -1 of Fig. 1 and shown as rectangular in cross section, extends vertically up the center of the tower. As shown, ,.,~; ~
it has an inlet 33 (Fig. 3) leading into its lower end. .
The inlet may be at any elevation depending upon the particular installation. The duct 32 has a solids discharge gate 34 at its bottom. The gate 34, which is provided with tipping valves or other suitable means forming an air lock, discharges into a solids collector conveyor 35 to dispose o~ any solids matter that may drop out of the raw gas in the raw gas duct.
At each module branch ducts, similar to the duct `~
19, 22, 23 lead from the raw gas duct 32 into the upper :
chamber of the module and from the module to a back flush receiver duct 37. Diverter valves corresponding to the valve 20 (Fig. 2) are arranged to direct the flow into the chamber as indicated by an arrow 38 ( Fig. 5) or from the chamber to the back flush receiver ducts as shown by arrow 39 ( Fig. 5).
~'04S~S~ ::
The back flush receiver duct 37, which may be either one or several individual ducts, leads into a cyclone collector 40. The output of the cyclone passes through a fan 41 and into the raw gas duct 32. When several individual 5 back flush ducts are used it may be more convenient to supply more than one cyclone collector and fan than to supply the duck work required to lead all of the ducts into one cyclone. Also the provision of two or more cyclones and fans allows an equal number of modules to be back flushed 10 simultaneously.
The cleaned gas from the lower chamber 7 of each module flows through a branch duct 42 and a back flush ~ ~ va ~e
4~ 1 vl~vc 43 (shown as a disk valve) into a cleaned gas duct 44. As shown, there are two of the cleaned gas ducts to 15 simpli~y the duct work from the modules. Also, the modules shown in Fig. 3, 4, 5 are double units, each having two complete filter beds and upper and lower chambers.
The cyclone 40 or each cyclone if more than one are used has a solids discharge gate 45, equipped with 20 an air lock, connected to the conveyor 35 to dispose of the dust collected during back flush of the several filter beds.
One feature of this particular arrangement is the means for preheating the back flush gas to avoid cooling 25 the filter beds during back flush. Cooling the beds may cause condensation of vapors and lead to failure of the beds. In this arrangement a first run 46 of the back ; flush duct extends upwardly between and in heat exchange relation to the raw gas duct 32 and the cleaned gas duct 30 44. Thus heat is transferred from the hot raw gas and the hot cleaned gas to the back flush gas.
At the top of the tower, or at some other convenient place, a cross over duct 46 leads to a second run of the , . , : : .
l~S~)51.
back flush supply duct leading downwardly past the valves ~.
43. This duct is connected through the valves 43 to the .
adjacent modules for back flush gas flow as indicated by the arrow 47. :
The preferred arrangement with the modules stacked at several levels above each other and supplied through vertical ducts takes advantage of gravity to prevent solids ~ . , build up in the ducts as well as requiring relatively small '-area.
The duct work may also be arranged horizontally to provide the same flow paths except that means would :
then be required along each duct to dispose of solids that may settle out of the gas particularly in the raw gas duct and the back flush receiver duct.
This system thus provides a simple compact arrangement for a dust collector having a minimum number of fans or blowers, and high efficiency means for cleaning the collected ..
dust from the filter beds.
20 `
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... . .
, :
.`~,""'' , , 30 .
~;
The cyclone 40 or each cyclone if more than one are used has a solids discharge gate 45, equipped with 20 an air lock, connected to the conveyor 35 to dispose of the dust collected during back flush of the several filter beds.
One feature of this particular arrangement is the means for preheating the back flush gas to avoid cooling 25 the filter beds during back flush. Cooling the beds may cause condensation of vapors and lead to failure of the beds. In this arrangement a first run 46 of the back ; flush duct extends upwardly between and in heat exchange relation to the raw gas duct 32 and the cleaned gas duct 30 44. Thus heat is transferred from the hot raw gas and the hot cleaned gas to the back flush gas.
At the top of the tower, or at some other convenient place, a cross over duct 46 leads to a second run of the , . , : : .
l~S~)51.
back flush supply duct leading downwardly past the valves ~.
43. This duct is connected through the valves 43 to the .
adjacent modules for back flush gas flow as indicated by the arrow 47. :
The preferred arrangement with the modules stacked at several levels above each other and supplied through vertical ducts takes advantage of gravity to prevent solids ~ . , build up in the ducts as well as requiring relatively small '-area.
The duct work may also be arranged horizontally to provide the same flow paths except that means would :
then be required along each duct to dispose of solids that may settle out of the gas particularly in the raw gas duct and the back flush receiver duct.
This system thus provides a simple compact arrangement for a dust collector having a minimum number of fans or blowers, and high efficiency means for cleaning the collected ..
dust from the filter beds.
20 `
;.:
... . .
, :
.`~,""'' , , 30 .
~;
Claims (7)
1. A gravel bed dust collector system comprising in combination, a) at least two collector modules each comprising an upper and a lower chamber, a perforated partition separating the chambers and a bed of particulate filter material on the partition, b) a raw gas duct that receives the gas to be cleaned and that has solids material discharge means, c) a back flush receiver duct that extends generally parallel to the raw gas duct, d) first branch ducts including valves arranged to selectively connect the upper chamber of each module to the raw gas duct and the back flush receiver duct, e) a cleaned gas duct that extends generally parallel to the raw gas duct, f) a back flush gas supply duct, g) second branch ducts including valves arranged to selectively connect the lower chamber of each module to the cleaned gas duct and back flush gas supply duct, h) and a dust collector and fan arranged and connected in series between the back flush receiver duct and the raw gas duct, said fan serving to maintain the pressure in the back flush receiver duct less than the pressure in the raw gas duct, whereby, when the valves are in first positions gas may be drawn from the raw gas duct, downwardly through the bed of particulate filter material and into the cleaned gas duct, and when the valves are in second positions back flush gas from the back flush gas supply duct is drawn upwardly through the filter beds and the gas together with collected dust from the bed is carried through the back flush receiver dust into the dust collector.
2. A gravel bed dust collector system according to claim 1 in which said raw gas duct, said cleaned gas duct, and said back flush supply and receiver ducts are substantially vertical.
3. A gravel bed dust collector system according to claim 1 in which the dust collector is a cyclone separator connected to the back flush receiver duct.
4. A gravel bed dust collector system according to claim 2 in which a plurality of modules are divided into groups with each group occupying a level of a vertical array of groups.
5. A gravel bed dust collector according to claim 4 in which all of the groups of modules are oper-atively connected to a single raw gas duct, cleaned gas duct, and back flush supply and receiver ducts.
6. A gravel bed dust collector system according to claim 1 in which a parallelly directed run of the back flush gas supply duct is juxtaposed in heat exchange relation to at least one of the raw gas duct and the cleaned gas duct.
7. A gravel bed dust collector system according to claim 6 in which the raw gas duct, a cleaned gas duct, and parallelly directed runs of back flush supply ducts are juxtaposed to each other to form a vertical core and the modules of each group are arranged around the core.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US46337374A | 1974-04-23 | 1974-04-23 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1045051A true CA1045051A (en) | 1978-12-26 |
Family
ID=23839862
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA224,229A Expired CA1045051A (en) | 1974-04-23 | 1975-04-09 | Gravel bed dust collector |
Country Status (8)
| Country | Link |
|---|---|
| JP (1) | JPS50148981A (en) |
| AU (1) | AU8008975A (en) |
| BE (1) | BE827961A (en) |
| CA (1) | CA1045051A (en) |
| DE (1) | DE2517502A1 (en) |
| FR (1) | FR2268550A1 (en) |
| GB (1) | GB1501705A (en) |
| ZA (1) | ZA752364B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3311108A1 (en) * | 1983-03-26 | 1984-09-27 | Klöckner-Humboldt-Deutz AG, 5000 Köln | GAS CLEANING FILTER |
| CN113908657A (en) * | 2021-11-19 | 2022-01-11 | 马鞍山科宇环保设备股份有限公司 | Combined industrial dust collector with reverse dust blowing function at air outlet |
-
1975
- 1975-04-09 CA CA224,229A patent/CA1045051A/en not_active Expired
- 1975-04-11 GB GB14926/75A patent/GB1501705A/en not_active Expired
- 1975-04-11 AU AU80089/75A patent/AU8008975A/en not_active Expired
- 1975-04-14 ZA ZA00752364A patent/ZA752364B/en unknown
- 1975-04-15 BE BE155431A patent/BE827961A/en unknown
- 1975-04-19 DE DE19752517502 patent/DE2517502A1/en active Pending
- 1975-04-23 JP JP50050184A patent/JPS50148981A/ja active Pending
- 1975-04-23 FR FR7512688A patent/FR2268550A1/fr not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| GB1501705A (en) | 1978-02-22 |
| FR2268550A1 (en) | 1975-11-21 |
| ZA752364B (en) | 1976-03-31 |
| DE2517502A1 (en) | 1975-11-13 |
| BE827961A (en) | 1975-07-31 |
| JPS50148981A (en) | 1975-11-28 |
| AU8008975A (en) | 1976-10-14 |
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