CA1127561A - Method and apparatus for the intermittent, regenerating cleaning of a filter bed - Google Patents
Method and apparatus for the intermittent, regenerating cleaning of a filter bedInfo
- Publication number
- CA1127561A CA1127561A CA342,477A CA342477A CA1127561A CA 1127561 A CA1127561 A CA 1127561A CA 342477 A CA342477 A CA 342477A CA 1127561 A CA1127561 A CA 1127561A
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- CA
- Canada
- Prior art keywords
- space
- gas
- particles
- granular material
- filter bed
- 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
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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
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Filtering Of Dispersed Particles In Gases (AREA)
- Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)
Abstract
ABSTRACT
A shell and two perforated cylindrical walls are radially spaced about a common vertical axis so as to define three coaxial spaces. A gas to be purified of suspended particles is admitted to the annular first space between the shell and a filter bed of granular material in the second space between the two perforated walls, and a purified gas is withdrawn from the third space. To clean the filter bed, granular material is conveyed from the lowermost portion of the second space through a conduit to a separating device above the topmost portion of the filter bed by a stream of conveying gas, and the gas entrains most of the particles from the granular material while the latter returns to the second space by gravity. The particle-laden conveying gas is introduced tangen-tially into the top portion of the annular first space where it is mixed with a scavenging gas passed through the filter bed from the third to the first space.
The gas mixture with the particles suspended therein descends in a spiral path through the first space, the particles are precipitated as in a cyclone, and gas and particles are withdrawn separately from the bottom of the first space.
A shell and two perforated cylindrical walls are radially spaced about a common vertical axis so as to define three coaxial spaces. A gas to be purified of suspended particles is admitted to the annular first space between the shell and a filter bed of granular material in the second space between the two perforated walls, and a purified gas is withdrawn from the third space. To clean the filter bed, granular material is conveyed from the lowermost portion of the second space through a conduit to a separating device above the topmost portion of the filter bed by a stream of conveying gas, and the gas entrains most of the particles from the granular material while the latter returns to the second space by gravity. The particle-laden conveying gas is introduced tangen-tially into the top portion of the annular first space where it is mixed with a scavenging gas passed through the filter bed from the third to the first space.
The gas mixture with the particles suspended therein descends in a spiral path through the first space, the particles are precipitated as in a cyclone, and gas and particles are withdrawn separately from the bottom of the first space.
Description
The present invention relates to a method and apparatus for purifying a gas of particles suspended therein.
Dust-laden gases or those which are loaded with other impurities can be cleaned in known manner by the crude gas stream being caused to flow through a layer of granular filter material, consisting for example of silica sand.
During the course of operation, the granular filter bed becomes progressively more laden with dust particles until its increase in flow resistance necessi-tates regeneration, i.e. freeing the granular filter bed from dust.
Several methods for regenerative cleaning of granular filter material are known. It has for instance been suggested to draw off the filter material from time to time, to lead it outside of the filter system through a cleaning apparatus (cyclone) and then to return it to the filter after the dust has been successfully extracted. These systems require a large amount of conveying means since the filter material must firstly be drawn off at the lower part of the filter system, then conveyed vertically upwards and finally led into the filter again from above.
In order to overcome this disadvantage, the suggestion has been made to arrange the granular filter bed between two gas-permeable, coaxial tubes and to circulate the filter material in a closed cycle during regenerative cleaning.
For this purpose, the material is carried upwards by a conveyor gas stream from a central conveyor tube and falls again through the annular filter bed into the range of the conveying gas stream. Arranged in such systems between the outer tube of the filter bed and the casing shell is a crude gas chamber, through which crude gas flows during filtration, and dust-laden scavenging gas flows during the regeneration phase. It is unavoidable that dust swirling in the crude gas space also settles on the outer tube and thereby impairs the effec-tiveness of the filter system in the long run. Also, the dust-laden conveying gas must be led out of the filter system and cleaned by a separator before ~, ~
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discharge.
The present invention provides apparatus for purifying a gas of particles suspended therein which comprises:
(a) a shell;
(b) two walls in said shell (1) said walls being annular about a common, vertically extending axis,
Dust-laden gases or those which are loaded with other impurities can be cleaned in known manner by the crude gas stream being caused to flow through a layer of granular filter material, consisting for example of silica sand.
During the course of operation, the granular filter bed becomes progressively more laden with dust particles until its increase in flow resistance necessi-tates regeneration, i.e. freeing the granular filter bed from dust.
Several methods for regenerative cleaning of granular filter material are known. It has for instance been suggested to draw off the filter material from time to time, to lead it outside of the filter system through a cleaning apparatus (cyclone) and then to return it to the filter after the dust has been successfully extracted. These systems require a large amount of conveying means since the filter material must firstly be drawn off at the lower part of the filter system, then conveyed vertically upwards and finally led into the filter again from above.
In order to overcome this disadvantage, the suggestion has been made to arrange the granular filter bed between two gas-permeable, coaxial tubes and to circulate the filter material in a closed cycle during regenerative cleaning.
For this purpose, the material is carried upwards by a conveyor gas stream from a central conveyor tube and falls again through the annular filter bed into the range of the conveying gas stream. Arranged in such systems between the outer tube of the filter bed and the casing shell is a crude gas chamber, through which crude gas flows during filtration, and dust-laden scavenging gas flows during the regeneration phase. It is unavoidable that dust swirling in the crude gas space also settles on the outer tube and thereby impairs the effec-tiveness of the filter system in the long run. Also, the dust-laden conveying gas must be led out of the filter system and cleaned by a separator before ~, ~
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discharge.
The present invention provides apparatus for purifying a gas of particles suspended therein which comprises:
(a) a shell;
(b) two walls in said shell (1) said walls being annular about a common, vertically extending axis,
(2) said shell and one of said walls defining therebetween a first space annular about said axis,
(3) said walls defining therebetween a second space annular about said axis,
(4) the other one of said walls bounds a third space therein;
(c) a filter bed of granular material in said second space, (1) said walls being formed with perforations permeable to the gas to be purified and to at least a portion of said particles;
(d) a conveying conduit having a bottom orifice communicating with the lowermost portion of said second space and upwardly extending therefrom;
(e) feeding means for feeding a gas under pressure to said bottom orifice and the communicating lowermost portion of said second space, said con-duit having a top orifice, whereby a mixture of said gas under pressure and of said granular material is conveyed upwardly through said conduit and discharged from said top orifice when said gas under pressure is fed to said bottom orificeand said lowermost portion;
(f) separating means for separating the granular material from the gas in said mixture, said separating means communicating with said top orifice in such a manner so as to receive the mixture discharged from said top orifice and with the topmost portion of said second space in such a manner so as to permit downward movement of the separated granular material from said separating 75~'~
means to said second space;
(g) a connecting conduit connecting said separating means with said first space for flow of the separated gas from said separating means to said first space;
(h) inlet means for admitting the gas to be purified to said first space, (i) outlet means for withdrawing purified gas from said third space; and (j) supply means for supplying a scavenging gas to said third space.
From another aspect, the invention provides in a method of purifying a gas of suspended particles in which the gas to be purified is passed from a first space to a third space through a filter bed of granular material confined in a second space between perforated, vertically extending walls, whereby at least a portion of said particles is retained by said granular material, said second space having topmost and lowermost portions, and purified gas is with-drawn from said third space in each of a plurality of filtering phases, granular material carrying retained particles is withdrawn from said lowermost portion during each of a plurality of filter bed cleaning phases alternating with said filtering phases by suspending the granular material in a stream of conveying gaseous material flowing toward a zone above said topmost portion, the suspended granular material is separated in said zone from said stream and said particles, the particles being suspended in said stream, the granular material being returned to said second space by gravity, the improvement which comprises:
(a) withdrawing the separated gaseous material and the particles suspended therein from said zone, (b) introducing the withdrawn material and the particles into said first space, and (c) separately withdrawing said gaseous material and the particles , ~
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from said first space during each of said cleaning phases.
An embodiment of the inventive subject matter is illustrated, by way of example only, in the accompanying drawings, wherein:-Figure 1 is a simplified vertical section of a filter unit showingit in its operational phase (cleaning crude gas);
Figure 2 is a cross-section on the line II - II in Figure 1 and simultaneously illustrates the parallel connection of several filter units;
Figure 3 is a cross-section on line III - III in Figure l;
Figure 4 is a cross-section on line IV - IV in Figure 5;
Figure 5 shows the filter unit shown in Figures 1 to 4 during the regenerative cleaning phase (cleaning filter bed); and Figure 6 is a vertical cross-section of a variant.
The schematic filter unit (illustrated without showing unimportant details) has a casing 1 which has on its upper part an inlet opening 2 for scavenging gas which enters via a scavenging gas pipe 3. Cn the opposite side of the casing 1 there is an outlet opening 4 for the purified gas which flows off through a pipe 5. By means of two gates 7 and 8 the openings 2 and 4 can be closed alternately, under command impulses that can, for example, originate from a schematically indicated servomotor M.
Inside the practically circular cylindrical casing 1 are two gas-permeable, coaxial cylindrical pipes 9, 10. The space between these two pipes is filled with a filter bed 11 consisting of a granular material, for example silica sand.
The two gas-permeable perforated pipes 9,10 taper towards the bottom.
Joining the lowest part of the outer pipe 9 is a conveying gas pipe 12, in which a throttle valve 13 and a porous, i.e. gas-permeable, plate 29 are mounted.
A central conveyor tube 14 extends upwards from the lowest, central point of the inner pipe 10. Above the upper mouth of the conveyor tube 14 is a deflecting S6~
member 15 which is shaped like an inverted cone and therefore has a downward-tapering deflection surface. The deflecting member 15 is attached to the housing 18 of a separating device by means of struts 16. The housing 18 is constructed as a double cone, the widest section of which lies approximately in its middle area. This housing 18 is connected by a pipe 19 to the space between the outer pipe 9 and the casing 1, which will now be called the crude gas chamber 20.
The two gates 7 and 8 are joined together by two rods 6 and traverses (not shown) arranged in the region of the gates. The rods 6 lie therefore on both sides of the separating housing 18 and rigidly couple the gates 7,8.
; A crude gas channel 21 opens into the casing 1 and arranged in the conically tapering lower section of the casing 1 in a conduit 22 a discharge conveyor, preferably a discharge screw 23. The crude gas channel 21 is limited laterally by two parallel, vertical walls 39 and 40.
As shown in Figure 1 and Figure 2, several filter units are arranged consecutively in a filter system and are fed by a common crude gas channel 21.
Neighbouring filter units are separated from one another in their lower sectionsbelow a floor 34 by vertical walls 33 and are connected to the crude gas channel 21 by openings 35.
Four radially-directed drop pipes 24 open into the bottom of the housing 18, connecting the space enclosed within the housing 18 to the filter bed 11. The drop pipes 24 are inclined downwards towards the filter bed at an angle which is larger than the angle of repose of the granular material used.
The connecting pipe 19 from the separating housing 18 to the crude gas chamber 20 as shown in Figure 3 opens preferably tangentially into the uppersection of the crude gas chamber 20.
As mentioned before, the filter unit shown in Figure 1 is to be thought of as a part of a system which comprises several such units, so that one of the elements can be regenerated as desired while the other elements maintain the cleaning operation of the crude gas.
In the crude gas cleaning operation, the dust-laden crude gas flows according to Figure 1 through the channel 21 into the crude gas chamber 20, flows subsequently through the filter bed 11 and leaves the inner, clean gas chamber surrounded by the filter bed through the spaces 25 between the pipes 24 (Figure 3). The clean gas then reaches the outlet 5 through the opening 4, the conveying gas valve 13 being closed.
If the filter bed material is to be regenerated, the conveying gas throttle valve 13 is opened (Figure 5). The gate 7 uncovers the flow-in opening for scavenging gas which then flows through the spaces 25 (Figure 3) into the clean gas chamber of the filter and from there through the filter bed 11 (see Figure 4) radially outwards (arrows 27) into the crude gas chamber 20.
The conveying gas stream flows, as mentioned, through the pipe 19 tangentially into the crude gas chamber 20. Since the crude gas chamber 20 is one of two annular spaces bounded by the cylindrical walls 1,9, the conveying gas $tream flows downwards in a helical path S (Figure 5). In this way, it mixes with the scavenging gas stream (arrows 27) which picks up dust from the filter bed 11, so that dust granules flushed out of the filter bed 11 by the scavenging gas follow the downward helical path.
If this dust-laden gas stream were to enter the lower collecting room 26 at all parts of its periphery, a large portion of the dust would then enter the crude gas channel 21 and therefore pass to the other filter elements. To avoid this, the entrance point E of the conveying gas pipe 19 is arranged in relation to the dimensions of the casing 1 and the gas flow speed in such a position on the circumference of the casing 1 that the end point Z of the helical path S lies at least substantially diametrically opposite the opening 35 (which serves as a flow-in opening during the crude gas cleaning operation).
i;6~
Thanks to this arrangement, the major part D of the dust is separated from the gas, not in the flow out region of the gas, but opposite the outlet opening 35, and slides downwards along the inclined wall 36 and is removed by the screw conveyor.
It will be clear to the person skilled in the art that the point Z
not only lies diametrically opposite the opening 35, but in fact covers a : relatively wide zone, as indicated in Figure 2.
The entrance point E (Figure 5) is determined experimentally by firstly determining the pitch h of the helical path S and then, beginning from point Z, plotting the helical path along the inner wall of the casing 1.
The vertical distance of the points E and Z is a whole multiple of the pitch h.
Through the co-operation of the radially directed scavenging gas stream 27 and the tangentially inflowing conveying gas stream 28, a cyclone effect results which provides intensive dust separation and prevents con-tamination of the outer surface of the pipe 9, Due to the abrupt interruption of the helical line S at point Z
caused by the sudden widening of the lower chamber 26, dust circulating near the walls quickly falls.
Since the crude gas is sucked through the crude gas channel 21 by means of a suction fan (not shown) arranged at the end of the channel, there is a sub-pressure in this channel so that the mixed scavenging and conveying gas stream is drawn without difficulty through the opening 35 (Figures 2 and 5) into the crude gas stream.
As shown in Figure 5, the granular filter material is caught by the conveying gas stream at the lowest point of the filter bed 11 and is conveyed upwards in the conveyor tube 14. After leaving the conveyor tube 14, the granular material strikes the deflecting member 15. The filter material l~Z75~j~
granules rebound from the deflecting member 15 and are guided downwards by the inner surface of the casing 18 and are returned to the filter bed 11 through the drop pipes 24. The conveying gas leaves the separating device 17 through the pipe 19 and enters, as already mentioned, the crude gas chamber 20 tangentially at point E (Figure 5).
Figure 6 shows a variant where like parts are marked with the same reference numerals. Contrary to the embodiment as per Figures 1-5, the convey-ing gas pipe 37 is led concentrically downwards in the conveyor tube 14 and opens into a deflection chamber 38 arranged below the conveyor tube 14. The conveying gas entering deflection chamber 38 is deflected upwards and sweeps the granules of the filter bed 11 in the annular space 12 upwards. Apart from this differ-ence, the filter unit works as described on the basis of Figures 1 to 4.
(c) a filter bed of granular material in said second space, (1) said walls being formed with perforations permeable to the gas to be purified and to at least a portion of said particles;
(d) a conveying conduit having a bottom orifice communicating with the lowermost portion of said second space and upwardly extending therefrom;
(e) feeding means for feeding a gas under pressure to said bottom orifice and the communicating lowermost portion of said second space, said con-duit having a top orifice, whereby a mixture of said gas under pressure and of said granular material is conveyed upwardly through said conduit and discharged from said top orifice when said gas under pressure is fed to said bottom orificeand said lowermost portion;
(f) separating means for separating the granular material from the gas in said mixture, said separating means communicating with said top orifice in such a manner so as to receive the mixture discharged from said top orifice and with the topmost portion of said second space in such a manner so as to permit downward movement of the separated granular material from said separating 75~'~
means to said second space;
(g) a connecting conduit connecting said separating means with said first space for flow of the separated gas from said separating means to said first space;
(h) inlet means for admitting the gas to be purified to said first space, (i) outlet means for withdrawing purified gas from said third space; and (j) supply means for supplying a scavenging gas to said third space.
From another aspect, the invention provides in a method of purifying a gas of suspended particles in which the gas to be purified is passed from a first space to a third space through a filter bed of granular material confined in a second space between perforated, vertically extending walls, whereby at least a portion of said particles is retained by said granular material, said second space having topmost and lowermost portions, and purified gas is with-drawn from said third space in each of a plurality of filtering phases, granular material carrying retained particles is withdrawn from said lowermost portion during each of a plurality of filter bed cleaning phases alternating with said filtering phases by suspending the granular material in a stream of conveying gaseous material flowing toward a zone above said topmost portion, the suspended granular material is separated in said zone from said stream and said particles, the particles being suspended in said stream, the granular material being returned to said second space by gravity, the improvement which comprises:
(a) withdrawing the separated gaseous material and the particles suspended therein from said zone, (b) introducing the withdrawn material and the particles into said first space, and (c) separately withdrawing said gaseous material and the particles , ~
75t~
from said first space during each of said cleaning phases.
An embodiment of the inventive subject matter is illustrated, by way of example only, in the accompanying drawings, wherein:-Figure 1 is a simplified vertical section of a filter unit showingit in its operational phase (cleaning crude gas);
Figure 2 is a cross-section on the line II - II in Figure 1 and simultaneously illustrates the parallel connection of several filter units;
Figure 3 is a cross-section on line III - III in Figure l;
Figure 4 is a cross-section on line IV - IV in Figure 5;
Figure 5 shows the filter unit shown in Figures 1 to 4 during the regenerative cleaning phase (cleaning filter bed); and Figure 6 is a vertical cross-section of a variant.
The schematic filter unit (illustrated without showing unimportant details) has a casing 1 which has on its upper part an inlet opening 2 for scavenging gas which enters via a scavenging gas pipe 3. Cn the opposite side of the casing 1 there is an outlet opening 4 for the purified gas which flows off through a pipe 5. By means of two gates 7 and 8 the openings 2 and 4 can be closed alternately, under command impulses that can, for example, originate from a schematically indicated servomotor M.
Inside the practically circular cylindrical casing 1 are two gas-permeable, coaxial cylindrical pipes 9, 10. The space between these two pipes is filled with a filter bed 11 consisting of a granular material, for example silica sand.
The two gas-permeable perforated pipes 9,10 taper towards the bottom.
Joining the lowest part of the outer pipe 9 is a conveying gas pipe 12, in which a throttle valve 13 and a porous, i.e. gas-permeable, plate 29 are mounted.
A central conveyor tube 14 extends upwards from the lowest, central point of the inner pipe 10. Above the upper mouth of the conveyor tube 14 is a deflecting S6~
member 15 which is shaped like an inverted cone and therefore has a downward-tapering deflection surface. The deflecting member 15 is attached to the housing 18 of a separating device by means of struts 16. The housing 18 is constructed as a double cone, the widest section of which lies approximately in its middle area. This housing 18 is connected by a pipe 19 to the space between the outer pipe 9 and the casing 1, which will now be called the crude gas chamber 20.
The two gates 7 and 8 are joined together by two rods 6 and traverses (not shown) arranged in the region of the gates. The rods 6 lie therefore on both sides of the separating housing 18 and rigidly couple the gates 7,8.
; A crude gas channel 21 opens into the casing 1 and arranged in the conically tapering lower section of the casing 1 in a conduit 22 a discharge conveyor, preferably a discharge screw 23. The crude gas channel 21 is limited laterally by two parallel, vertical walls 39 and 40.
As shown in Figure 1 and Figure 2, several filter units are arranged consecutively in a filter system and are fed by a common crude gas channel 21.
Neighbouring filter units are separated from one another in their lower sectionsbelow a floor 34 by vertical walls 33 and are connected to the crude gas channel 21 by openings 35.
Four radially-directed drop pipes 24 open into the bottom of the housing 18, connecting the space enclosed within the housing 18 to the filter bed 11. The drop pipes 24 are inclined downwards towards the filter bed at an angle which is larger than the angle of repose of the granular material used.
The connecting pipe 19 from the separating housing 18 to the crude gas chamber 20 as shown in Figure 3 opens preferably tangentially into the uppersection of the crude gas chamber 20.
As mentioned before, the filter unit shown in Figure 1 is to be thought of as a part of a system which comprises several such units, so that one of the elements can be regenerated as desired while the other elements maintain the cleaning operation of the crude gas.
In the crude gas cleaning operation, the dust-laden crude gas flows according to Figure 1 through the channel 21 into the crude gas chamber 20, flows subsequently through the filter bed 11 and leaves the inner, clean gas chamber surrounded by the filter bed through the spaces 25 between the pipes 24 (Figure 3). The clean gas then reaches the outlet 5 through the opening 4, the conveying gas valve 13 being closed.
If the filter bed material is to be regenerated, the conveying gas throttle valve 13 is opened (Figure 5). The gate 7 uncovers the flow-in opening for scavenging gas which then flows through the spaces 25 (Figure 3) into the clean gas chamber of the filter and from there through the filter bed 11 (see Figure 4) radially outwards (arrows 27) into the crude gas chamber 20.
The conveying gas stream flows, as mentioned, through the pipe 19 tangentially into the crude gas chamber 20. Since the crude gas chamber 20 is one of two annular spaces bounded by the cylindrical walls 1,9, the conveying gas $tream flows downwards in a helical path S (Figure 5). In this way, it mixes with the scavenging gas stream (arrows 27) which picks up dust from the filter bed 11, so that dust granules flushed out of the filter bed 11 by the scavenging gas follow the downward helical path.
If this dust-laden gas stream were to enter the lower collecting room 26 at all parts of its periphery, a large portion of the dust would then enter the crude gas channel 21 and therefore pass to the other filter elements. To avoid this, the entrance point E of the conveying gas pipe 19 is arranged in relation to the dimensions of the casing 1 and the gas flow speed in such a position on the circumference of the casing 1 that the end point Z of the helical path S lies at least substantially diametrically opposite the opening 35 (which serves as a flow-in opening during the crude gas cleaning operation).
i;6~
Thanks to this arrangement, the major part D of the dust is separated from the gas, not in the flow out region of the gas, but opposite the outlet opening 35, and slides downwards along the inclined wall 36 and is removed by the screw conveyor.
It will be clear to the person skilled in the art that the point Z
not only lies diametrically opposite the opening 35, but in fact covers a : relatively wide zone, as indicated in Figure 2.
The entrance point E (Figure 5) is determined experimentally by firstly determining the pitch h of the helical path S and then, beginning from point Z, plotting the helical path along the inner wall of the casing 1.
The vertical distance of the points E and Z is a whole multiple of the pitch h.
Through the co-operation of the radially directed scavenging gas stream 27 and the tangentially inflowing conveying gas stream 28, a cyclone effect results which provides intensive dust separation and prevents con-tamination of the outer surface of the pipe 9, Due to the abrupt interruption of the helical line S at point Z
caused by the sudden widening of the lower chamber 26, dust circulating near the walls quickly falls.
Since the crude gas is sucked through the crude gas channel 21 by means of a suction fan (not shown) arranged at the end of the channel, there is a sub-pressure in this channel so that the mixed scavenging and conveying gas stream is drawn without difficulty through the opening 35 (Figures 2 and 5) into the crude gas stream.
As shown in Figure 5, the granular filter material is caught by the conveying gas stream at the lowest point of the filter bed 11 and is conveyed upwards in the conveyor tube 14. After leaving the conveyor tube 14, the granular material strikes the deflecting member 15. The filter material l~Z75~j~
granules rebound from the deflecting member 15 and are guided downwards by the inner surface of the casing 18 and are returned to the filter bed 11 through the drop pipes 24. The conveying gas leaves the separating device 17 through the pipe 19 and enters, as already mentioned, the crude gas chamber 20 tangentially at point E (Figure 5).
Figure 6 shows a variant where like parts are marked with the same reference numerals. Contrary to the embodiment as per Figures 1-5, the convey-ing gas pipe 37 is led concentrically downwards in the conveyor tube 14 and opens into a deflection chamber 38 arranged below the conveyor tube 14. The conveying gas entering deflection chamber 38 is deflected upwards and sweeps the granules of the filter bed 11 in the annular space 12 upwards. Apart from this differ-ence, the filter unit works as described on the basis of Figures 1 to 4.
Claims (12)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. Apparatus for purifying a gas of particles suspended therein which comprises:
(a) a shell;
(b) two walls in said shell (1) said walls being annular about a common, vertically extending axis, (2) said shell and one of said walls defining therebetween a first space annular about said axis, (3) said walls defining therebetween a second space annular about said axis, (4) the other one of said walls bounds a third space therein;
(c) a filter bed of granular material in said second space, (1) said walls being formed with perforations permeable to the gas to be purified and to at least a portion of said particles;
(d) a conveying conduit having a bottom orifice communicating with the lowermost portion of said second space and upwardly extending therefrom;
(e) feeding means for feeding a gas under pressure to said bottom orifice and the communicating lowermost portion of said second space, said con-duit having a top orifice, whereby a mixture of said gas under pressure and of said granular material is conveyed upwardly through said conduit and discharged from said top orifice when said gas under pressure is fed to said bottom orifice and said lowermost portion;
(f) separating means for separating the granular material from the gas in said mixture, said separating means communicating with said top orifice in such a manner so as to receive the mixture discharged from said top orifice and with the topmost portion of said second space in such a manner so as to per-mit downward movement of the separated granular material from said separating means to said second space;
(g) a connecting conduit connecting said separating means with said first space for flow of the separated gas from said separating means to said first space;
(h) inlet means for admitting the gas to be purified to said first space, (i) outlet means for withdrawing purified gas from said third space;
and (j) supply means for supplying a scavenging gas to said third space.
(a) a shell;
(b) two walls in said shell (1) said walls being annular about a common, vertically extending axis, (2) said shell and one of said walls defining therebetween a first space annular about said axis, (3) said walls defining therebetween a second space annular about said axis, (4) the other one of said walls bounds a third space therein;
(c) a filter bed of granular material in said second space, (1) said walls being formed with perforations permeable to the gas to be purified and to at least a portion of said particles;
(d) a conveying conduit having a bottom orifice communicating with the lowermost portion of said second space and upwardly extending therefrom;
(e) feeding means for feeding a gas under pressure to said bottom orifice and the communicating lowermost portion of said second space, said con-duit having a top orifice, whereby a mixture of said gas under pressure and of said granular material is conveyed upwardly through said conduit and discharged from said top orifice when said gas under pressure is fed to said bottom orifice and said lowermost portion;
(f) separating means for separating the granular material from the gas in said mixture, said separating means communicating with said top orifice in such a manner so as to receive the mixture discharged from said top orifice and with the topmost portion of said second space in such a manner so as to per-mit downward movement of the separated granular material from said separating means to said second space;
(g) a connecting conduit connecting said separating means with said first space for flow of the separated gas from said separating means to said first space;
(h) inlet means for admitting the gas to be purified to said first space, (i) outlet means for withdrawing purified gas from said third space;
and (j) supply means for supplying a scavenging gas to said third space.
2. Apparatus as set forth in claim 1, wherein said shell and said one wall have respective faces bounding said first space therebetween, one of said faces being arcuate about said axis, and said connecting conduit having an orifice directed inward of said first space in a direction approximately tangential to said one face.
3. Apparatus as set forth in claim 2, wherein said faces of said shell and said one wall are substantially circular in cross-section transverse to said axis, whereby said first space is circularly arcuate in cross-section, said direction being approximately tangential to said first space.
4. Apparatus as set forth in claim 1, wherein said separating means includes a casing and baffle means in said casing for deflecting the mixture discharged from said top orifice against said casing.
5. Apparatus as set forth in claim 4, wherein said baffle means includes a baffle member having a tip opposite said top orifice and flaring from said tip in an upward direction away from said top orifice.
6. Apparatus as set forth in claim 4, wherein said conveying conduit extends from said lowermost portion through said third space to said separating means, the separating means further including a plurality of pipes angularly distributed about said conveying conduit and connecting said casing to said topmost portion.
7. Apparatus as set forth in claim 1, 2 or 3 wherein said feeding means includes a feeding conduit passing through said conveying conduit between the orifices thereof.
8. Apparatus as set forth in claim 1, 2 or 3 further comprising means for withdrawing solid particles from the lowermost portion of said first space.
9. In a method of purifying a gas of suspended particles in which the gas to be purified is passed from a first space to a third space through a filter bed of granular material confined in a second space between perforated, vertical-ly extending walls, whereby at least a portion of said particles is retained by said granular material, said second space having topmost and lowermost portions, and purified gas is withdrawn from said third space in each of a plurality of filtering phases, granular material carrying retained particles is withdrawn from said lowermost portion during each of a plurality of filter bed cleaning phases alternating with said filtering phases by suspending the granular material in a stream of conveying gaseous material flowing toward a zone above said top-most portion, the suspended granular material is separated in said zone from said stream and said particles, the particles being suspended in said stream, the granular material being returned to said second space by gravity, the improvement which comprises:
(a) withdrawing the separated gaseous material and the particles suspended therein from said zone, (b) introducing the withdrawn material and the particles into said first space, and (c) separately withdrawing said gaseous material and the particles from said first space during each of said cleaning phases.
(a) withdrawing the separated gaseous material and the particles suspended therein from said zone, (b) introducing the withdrawn material and the particles into said first space, and (c) separately withdrawing said gaseous material and the particles from said first space during each of said cleaning phases.
10. In a method as set forth in claim 9, scavenging gas being passed through said filter bed from said third space to said first space during each of said cleaning phases and being mixed with said withdrawn gaseous material in said first space.
11. In a method as set forth in claim 10, said first space being annular about a vertically extending axis, and said withdrawn material and particles being introduced into said first space in a substantially tangential direction.
12. In a method as set forth in claim 11, said gaseous material and particles being introduced into the topmost portion of said first space so as to move downward in said first space in a path spiraling about said axis.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CH1314278A CH637845A5 (en) | 1978-12-22 | 1978-12-22 | METHOD AND DEVICE FOR INTERMITTENT, REGENERATIVE CLEANING OF A FILTER BED. |
| CH13'142/78 | 1978-12-22 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1127561A true CA1127561A (en) | 1982-07-13 |
Family
ID=4389688
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA342,477A Expired CA1127561A (en) | 1978-12-22 | 1979-12-21 | Method and apparatus for the intermittent, regenerating cleaning of a filter bed |
Country Status (10)
| Country | Link |
|---|---|
| JP (1) | JPS5588819A (en) |
| AU (1) | AU5405279A (en) |
| CA (1) | CA1127561A (en) |
| CH (1) | CH637845A5 (en) |
| DE (1) | DE2951877A1 (en) |
| ES (1) | ES247612Y (en) |
| FR (1) | FR2444490A1 (en) |
| GB (1) | GB2038200B (en) |
| SE (1) | SE7910615L (en) |
| ZA (1) | ZA796966B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GR78597B (en) * | 1982-06-22 | 1984-09-27 | Gimag Ag | |
| DE3424170A1 (en) * | 1984-06-30 | 1986-02-27 | Metallgesellschaft Ag, 6000 Frankfurt | CLINKER COOLER WITH DEDUSTING DEVICE IN A METHOD FOR THE PRODUCTION OF CEMENT |
| US5342427A (en) * | 1992-12-29 | 1994-08-30 | Edmeston Ab | Apparatus for cullet preheating and polluting emission reduction in the glass manufacturing process |
| US5855636A (en) * | 1995-12-12 | 1999-01-05 | Edmeston Ab | Method which removes odor and pollutants when preparing cullet for use in an electrostatic bed filter |
| CN102805986B (en) * | 2012-05-25 | 2016-08-31 | 湖州师范学院 | The double louver mobile layer granule Multi-effect dust of preposed whirlwind |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2539042B2 (en) * | 1975-09-02 | 1980-07-24 | Waeschle Maschinenfabrik Gmbh, 7980 Ravensburg | Method and device for temperature treatment of or for mass transfer in bulk material |
| CH614128A5 (en) * | 1976-05-06 | 1979-11-15 | Gimag Ag |
-
1978
- 1978-12-22 CH CH1314278A patent/CH637845A5/en not_active IP Right Cessation
-
1979
- 1979-12-20 AU AU54052/79A patent/AU5405279A/en not_active Abandoned
- 1979-12-20 ES ES1979247612U patent/ES247612Y/en not_active Expired
- 1979-12-21 GB GB7944040A patent/GB2038200B/en not_active Expired
- 1979-12-21 CA CA342,477A patent/CA1127561A/en not_active Expired
- 1979-12-21 SE SE7910615A patent/SE7910615L/en not_active Application Discontinuation
- 1979-12-21 ZA ZA00796966A patent/ZA796966B/en unknown
- 1979-12-21 DE DE19792951877 patent/DE2951877A1/en not_active Withdrawn
- 1979-12-21 FR FR7931405A patent/FR2444490A1/en active Granted
- 1979-12-21 JP JP16744979A patent/JPS5588819A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| ES247612U (en) | 1980-09-01 |
| SE7910615L (en) | 1980-06-23 |
| ZA796966B (en) | 1980-11-26 |
| GB2038200B (en) | 1983-03-23 |
| FR2444490A1 (en) | 1980-07-18 |
| JPS5588819A (en) | 1980-07-04 |
| FR2444490B1 (en) | 1983-04-22 |
| GB2038200A (en) | 1980-07-23 |
| DE2951877A1 (en) | 1980-07-10 |
| AU5405279A (en) | 1980-06-26 |
| CH637845A5 (en) | 1983-08-31 |
| ES247612Y (en) | 1981-01-01 |
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| MKEX | Expiry |