CA1195622A - Gas borne particle filtering method - Google Patents
Gas borne particle filtering methodInfo
- Publication number
- CA1195622A CA1195622A CA000429409A CA429409A CA1195622A CA 1195622 A CA1195622 A CA 1195622A CA 000429409 A CA000429409 A CA 000429409A CA 429409 A CA429409 A CA 429409A CA 1195622 A CA1195622 A CA 1195622A
- Authority
- CA
- Canada
- Prior art keywords
- filter medium
- belt
- casing
- projections
- strands
- 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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- Filtering Of Dispersed Particles In Gases (AREA)
- Filtering Materials (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A gas borne particle filtering apparatus having a filter medium (13) with inlet and outlet openings (11, 12) in a staggered sawtooth cross-sectional configuration (140, 141) in a casing (10) for the filter medium positioned such that the gas passes along and between the sawteeth on both sides of the filter medium is described. A screened belt or support (14) for the filter medium is described and method for the use thereof is also described. The apparatus and method are particularly suited to cleaning heated or cooled air in a confined work space in a factory containing small micron sized particles so that the air can be recycled.
A gas borne particle filtering apparatus having a filter medium (13) with inlet and outlet openings (11, 12) in a staggered sawtooth cross-sectional configuration (140, 141) in a casing (10) for the filter medium positioned such that the gas passes along and between the sawteeth on both sides of the filter medium is described. A screened belt or support (14) for the filter medium is described and method for the use thereof is also described. The apparatus and method are particularly suited to cleaning heated or cooled air in a confined work space in a factory containing small micron sized particles so that the air can be recycled.
Description
~s~;~z HaTnmon~L 4 . 1--2 GAS BOE~NE PARTICLE FI~iTERING METHOD
B KGROUND OF TEIE INVENTION
1. Fi~1d o~ the Invention ~ . ~
The present invention relates to an impro~ed gas filter~ng apparatus and methodO In particular the p~esent inventlc,n re.a~es '~o an apparatus and ~lethcd adapte~ ~or cleaning air of small, micron sized particles.
B KGROUND OF TEIE INVENTION
1. Fi~1d o~ the Invention ~ . ~
The present invention relates to an impro~ed gas filter~ng apparatus and methodO In particular the p~esent inventlc,n re.a~es '~o an apparatus and ~lethcd adapte~ ~or cleaning air of small, micron sized particles.
2. Prior Art The prior art is concerned with conserva~ion oE
energy used to h~at a gas, particularly air, used in a confined work space where small particles are generated.
Under manufacturing conditions, a.ir can accu~ula~e very fine micron sized particles which are a health hazard and whi~h can create a fire hazard. In many plants, in the wihter, the particle laden, heated air is vented to the ~tm~sphere and fresh air is heated rom outside ambient temperatu.res for use in the building. In the 5ummer, the rever~e is ~rue and cooled air is vented. This process is a waste o~ energy~ since the article laden gas OL air can be clean~ed and recycled.
U~S. Patent No. 1,965,717 to Wechsber~ describe~ a du~t filter device as ~oes Canadian Patent ~o. 1,072~890 to _ermans. In these devices the filter medium is unsupporte~ and the filter3 are concerned ~i~h dust SL2ed particle~ ~50 microns and abo~e~ The air flow is parallel to the surace of the ilter medium.
~he prior art is faced with the problem of pr~viding appropriate filter medi~m and filtering apparatus which allows for iltering of micron sized partLcles ~, ~s~
particularly for welding smoke and oil ~is~. The problem is to remove micron ~ized particles such as smoke or oil mist. Generally the prior art has used apparatus w~erein gas flow towards the filter medium is perpendicular to the general plane o~ the medium, tending to dri~e the particles through the mediumO ~ecause o the density of the ~ilter medium a porous support must be used for support of and transfer of the filter med;umO
The prior art shows various types of fllter ~edia having a sawtoothed conflguration. In all of this prior art where a porous support is used the gas flow is directed towards the projections def;ning the sawtoothed confi~uration with the gas flow perpendicular to the general plane defined by the filter medium~ I have found lS that the particles in the gas tend to be driven directly through the filter medium even with this configurationO
Also this gas flow creates turbulence at the filter medium surface and tend~ to dislodge particles embedded in the mediumO
U.S0 Pa~ent No. 2,016,991 to Dollinqer, shows the use of moveable screen belts 7a ~upporting a filter medium in a sinuou~ path where the gas flow p is directed towards the projections and the general plane o~ the filter medium.
The Eilter medium is slightl~ wider than the width of the ca3ing 4 which forms a seal with the walls of the ca~ing~
ll,S, Patent No. 1~982,~39 to Chris~o~erson shows a d~vice wherein non~moveable screens 31 position the filter m~dia B during filtration. Automatic feed means is provided ~or advancement o the filter media. The gas 10w ~0 1~ directed towards the pro~ectiorls and the general plane of filter medium.
U.S~ Patent NoO~2,076,305 to ~ shows a similar type o~ device to t~at described by Dollin~er without the moveable screen.
U.S. Patent No. 2,133,931 to Wal~er et al des~ribes a mechanism for forming a sinuous filter medium whereb~
wedge shaped clamping rails 28 and 29 on slide plates 14 are moveable to engage the filter medla A during filtrationO
The gas flow is the same as ~
~5~
U.S~ Patent No. 3,019~855 to Engle describe~
specific means ~or securing the edges of the filter media 45 and al~o a mean~ ~or detecting the dif~erence in pressure in the filter media in order to provid~ for advancement for the fresh mediaO The gas flow is the same as the earlier paten~s.
~ S~ Patent No. 3,045,410 to loyd show~ a roll type device wherein the rclls 12 are in contact with the filter media 19. The gas 1Ow is conventionalO
U.S. Patent No. 3,406,503 also to Floyd shows a mechanism for the edge support of the ~ilter me~ia. The gas flow is con~entional.
U.S. Patent No~ 3,438,588 to Steinholtz et al shows a device wherein the filter media 1 is continuously fed 1~ rom a roller 2 ln 2 zigzag R sawtoothed or sinuous pathO
The gas flow is conventional.
U~S. Patent No. 3,552,099 to ~y~ shows a sawtoothed type filter web with a specific form of ~ealing means or ~he filter media 30. The gas flow is conventionaJ.
One of the earliest patents i~ ~irkholz, U.S.
Patent No. 1,783,181, wherein a rotary drum ~upports a moveable filter media. ~his patent describes the use of automatic means to advance the filter media after it encounters objectionable resistance because o ~he accumulation of particles. U.S. Patent No. 3,596,442 to Neumann and U.S. Patent No. 3,745~748 to Goldfield show i.mprovements on this basic patent. The gas flow is co~ventional.
There are numerous other patents showing various devices to be used with gas ~air) filters or other filter mediu~ configuration-~, including Patent Nos. 2,113~896;
2~881,~59; 2,848,064; 2,853,155; 3,02~,976; 3,332,~15;
energy used to h~at a gas, particularly air, used in a confined work space where small particles are generated.
Under manufacturing conditions, a.ir can accu~ula~e very fine micron sized particles which are a health hazard and whi~h can create a fire hazard. In many plants, in the wihter, the particle laden, heated air is vented to the ~tm~sphere and fresh air is heated rom outside ambient temperatu.res for use in the building. In the 5ummer, the rever~e is ~rue and cooled air is vented. This process is a waste o~ energy~ since the article laden gas OL air can be clean~ed and recycled.
U~S. Patent No. 1,965,717 to Wechsber~ describe~ a du~t filter device as ~oes Canadian Patent ~o. 1,072~890 to _ermans. In these devices the filter medium is unsupporte~ and the filter3 are concerned ~i~h dust SL2ed particle~ ~50 microns and abo~e~ The air flow is parallel to the surace of the ilter medium.
~he prior art is faced with the problem of pr~viding appropriate filter medi~m and filtering apparatus which allows for iltering of micron sized partLcles ~, ~s~
particularly for welding smoke and oil ~is~. The problem is to remove micron ~ized particles such as smoke or oil mist. Generally the prior art has used apparatus w~erein gas flow towards the filter medium is perpendicular to the general plane o~ the medium, tending to dri~e the particles through the mediumO ~ecause o the density of the ~ilter medium a porous support must be used for support of and transfer of the filter med;umO
The prior art shows various types of fllter ~edia having a sawtoothed conflguration. In all of this prior art where a porous support is used the gas flow is directed towards the projections def;ning the sawtoothed confi~uration with the gas flow perpendicular to the general plane defined by the filter medium~ I have found lS that the particles in the gas tend to be driven directly through the filter medium even with this configurationO
Also this gas flow creates turbulence at the filter medium surface and tend~ to dislodge particles embedded in the mediumO
U.S0 Pa~ent No. 2,016,991 to Dollinqer, shows the use of moveable screen belts 7a ~upporting a filter medium in a sinuou~ path where the gas flow p is directed towards the projections and the general plane o~ the filter medium.
The Eilter medium is slightl~ wider than the width of the ca3ing 4 which forms a seal with the walls of the ca~ing~
ll,S, Patent No. 1~982,~39 to Chris~o~erson shows a d~vice wherein non~moveable screens 31 position the filter m~dia B during filtration. Automatic feed means is provided ~or advancement o the filter media. The gas 10w ~0 1~ directed towards the pro~ectiorls and the general plane of filter medium.
U.S~ Patent NoO~2,076,305 to ~ shows a similar type o~ device to t~at described by Dollin~er without the moveable screen.
U.S. Patent No. 2,133,931 to Wal~er et al des~ribes a mechanism for forming a sinuous filter medium whereb~
wedge shaped clamping rails 28 and 29 on slide plates 14 are moveable to engage the filter medla A during filtrationO
The gas flow is the same as ~
~5~
U.S~ Patent No. 3,019~855 to Engle describe~
specific means ~or securing the edges of the filter media 45 and al~o a mean~ ~or detecting the dif~erence in pressure in the filter media in order to provid~ for advancement for the fresh mediaO The gas flow is the same as the earlier paten~s.
~ S~ Patent No. 3,045,410 to loyd show~ a roll type device wherein the rclls 12 are in contact with the filter media 19. The gas 1Ow is conventionalO
U.S. Patent No. 3,406,503 also to Floyd shows a mechanism for the edge support of the ~ilter me~ia. The gas flow is con~entional.
U.S. Patent No~ 3,438,588 to Steinholtz et al shows a device wherein the filter media 1 is continuously fed 1~ rom a roller 2 ln 2 zigzag R sawtoothed or sinuous pathO
The gas flow is conventional.
U~S. Patent No. 3,552,099 to ~y~ shows a sawtoothed type filter web with a specific form of ~ealing means or ~he filter media 30. The gas flow is conventionaJ.
One of the earliest patents i~ ~irkholz, U.S.
Patent No. 1,783,181, wherein a rotary drum ~upports a moveable filter media. ~his patent describes the use of automatic means to advance the filter media after it encounters objectionable resistance because o ~he accumulation of particles. U.S. Patent No. 3,596,442 to Neumann and U.S. Patent No. 3,745~748 to Goldfield show i.mprovements on this basic patent. The gas flow is co~ventional.
There are numerous other patents showing various devices to be used with gas ~air) filters or other filter mediu~ configuration-~, including Patent Nos. 2,113~896;
2~881,~59; 2,848,064; 2,853,155; 3,02~,976; 3,332,~15;
3,337~89~; 3,350,853, 3,350,854; 3,464,487~ 39467,797;
3,348,366; 3,774,373; 4,229,187; 3~985~528; 4~011~067 and
3,348,366; 3,774,373; 4,229,187; 3~985~528; 4~011~067 and
4,054,5Zl. In all of the prior art devices the ~low of the ga~ is perpendicular to the general plane of the filter.
In some an electr~static charge is created ~.S. Patent No.
4,229,187) to facilitate t~e capture o~ the particle~.
Ob~ects It is therefore an object oE the present invention to provide a gas filtering apparatus and method for micron sized particles having a unique gas flow path which provides improved par~icle capture by the filter medium~
Further it is an object of the present invention to provide an apparatus and method which generate~ an electrostatic charge in the filter medium which enhances particle capture.
Further still it is an object of tha present invention to l.O provide an appa.ratus which is very compact, and relatively simple and inexpensive to construct. These and other obiects will become increasingly apparent by reference to the fo].lowing description and to the drawingsO
In the DrawincJs LS Figure 1 is a schematic cross-sectional plan view of the apparatus of the present invention particularly illustrating the gas 10w along the surface of a filter medium between the sawtoothed projections defined by a continuous filter bel t o Figure 2 is a schematic ~ront cross-sectional view o the apparatus shown in Figure 1 particularly ilLustrating the positioning of ~he sawtc~othed projections witll ~ails of arrows ~shown by a circle around an x) showing the gas flow along the surfaces o~ sawtoothed ~5 projections supporti.ng the fiLter medium.
Figure 3 is a front .isometric schematic vi~w o the preferred apparatus of t~e present invention showing the preferr~d staggered sawtooth conEiyuration such that the c3a~ p~sses along and between t~e projections and through the fi:Lter medium and particularly showing small partial cross-sections illustrating the location of sensor devicesq Figure 4 is a partial cross-sectional view of On2 sawtoo~hed projection shown in Figure 3 alon~ line 4~4 and particularly showing the ballooning of the filter medium and screened belt due to gas preRsure~
Figure S is a partial sectional view of a porous support~ such as t~e screened belt, ~howing bondi~g oE
intersection~ or ne~u~ between the non-metallic strand~
forming -the screened belt~
6~
Figure SA is a plan partial ~ectional view of a porou~ support, such as for a screened belt, where the nexus of s~rands in one first direction are crimped to restric~ movement of the strands oriented in the other S direction along the strands in the first direc~ion.
Figure SB is an isometric view partial sectioned view showing join;ng of ~he ends of a continuous belt~
Figure 6 is a schematic isometric vl ew showing the staggered positioning of por~ions of th~ outside cas.ing defining the sawtoothed con~iguration of -the projections.
Figures 7, 8 and 9 are graphs showing the performance o various polyester fiber filter media on a polyester strand screen, such as shown in Figure 5, used for the belt in bench testing.
lS General ~escri~tion The invention reiates to a gas borne particle Eiltering apparatus including a filter medium (13) having first and second surfaces (13a and 13b) and a depth (d3 between the surEaces~ an outer casing (10) havin~ an lnlet ~0 and an outlet opening ~11, 12), an endless moveable feed belt (14) in the casing defining rounded tip ~15) multiple sawtoothed cross-sectioned projections alternately pointed in two opposite first and second directions ~16 and 16a) which is located between the inlet anct ou~let openings, ~5 rollers (18) mounted on the ca~ing at the t;ps of the projectlon~ and moveably supporting the fil~er medium and b~Lt w.ith the first surface of khe filter medium adjacent ~he inlet opening and the second surface of the ilter medium in corltact with the belt~ whereill the inlet and the ~() outlet opening~ are separated by the filter medium in the casing or filtratlon and including means for moving the feed belt to remove the ilter medium and mean~ for collecting the re~oved filter medium the improvement which comprises:
~a) clo~ing the projections pointiny in the first direction ~16a) with a first side of the ca~ing (10) such that the projection~ pointlng in the ~econd direction ~16 define the înlet op~nings ~113; and (b) closing the projections pointing in the second direction (16) with a second opposite side of the casing (10) to the first side such that the projections pointing in the first direction (16a) define the outlet openings (12);
Wherein in use gas flow with the particles is along the first surface (13a) of the filter medium towards the sawtoothed projections closed pointed in the second direction (16) on the second side of the casing, then at an angle from the gas flwo along the first surface through the filter medium, then through the feed belt and ten along the second surface (13b) of the filter medium and the belt away from the projections closed in the opposite direction (16a) on the first side of the casing and then out the outlet opening.
The present invention also relates to a method of filtering gas borne particles in a filtering apparatus wherein the inlet and outlet openings (11 and 12) are separated by as filter medium (13) mounted on a porous support (14) for filtration, the improvement which comprises:
providing a small mesh screen as the porous support (14) composed of polymeric strands, the screen having a mesh size of about 6 or greaer in contact with a filter medium (13) wherein upon interaction of the screen in contact with the filter medium during gas flow an electrostatic charge is created which attracts 0.1 micron and larger sized particles to the filter medium for removal from the gas; and flowing a gas through the filter mdium and the screen at a gas velocity of between about 25 and 1000 feet per minute (12.5 to 5000 centimeters per second) at a pressure drop across the filter medium of less than about 2 inches of water (4.9 x 10-3 atmospheres), wherein an increasing percentage of the particles of a particular size are removed as a result of particle loading of the filter medium during filtration.
~s~
The present invention particularly relates to a continuous belt (14) for use in an apparatus or filtering gas borne particles with a EiltQr medium (13~ having a fîrst side ~13a) for receiving~the gas borne particles and S a second side tl3b) wherein the gas is removed without the par~icles, the improvement which comprises:
a continuous belt (14) in the ~orm Qf a small meshed non-metallic screen composed of polymeric strands havin~ nexus (24, 29) which are interbonded or crimped in the form of a con~inuous belt adapted to be in contact with the second side of the fil~er medium (13b) such that during gas flow interaction of the screen in contact with the ~ilter med;um produces an electrostatic charge which attracts 0.1 micron and larger sized particles.
Speci~ic ~ E~
Referring to Figures 1 to 3, the apparatus of the present invention is shown including an outer casin~ 10 having an inlet opening 11 and an outlet opening 1~
Filter medium 13 is mounted in t~e casing 10 on an endless moveahle feed belt 14 which defines rounded tip lS
sawtoothed projec~.ions 16 and l~a between the inlet opening 11 and the outlet opening 120 Roller 18 and 18a moveabl~
support the ~].t 14 ak the t.ips 15 of the projection.s 16 and 16a in the casing 10. ~eturn rollers 1~ and 19a support the retur~ of the belt 14 to the rollers l8a E~''L~ible se~ls 20 are connected to the casing 10 alld are in contact with the f.ilter medium 13 to prov.ide sealing oE the Eilter medium 13 between the inlet opening 11 and the out.l.~t op~ning 120 GeneraLly the filter medium 13 is fed 30 erOm a roll 21 and periodicalL~ removed when spent by particle loadi~g on a ta~eup roll 22 tensioned by a guide 23 outside the casing 10. The inlet opening 11 and the ou~let opening 12 are separated by the filter medium 13 for fi.ltration o the ga~ borne particle~. The rollers 13a and l9a have radially projecting wire brushes which positively en~age and align the belt 14~ The return roller l9a provides the drive means for the belt 14~ The preceding des~ription generally encompasse~ a number of prior art devices.
In some an electr~static charge is created ~.S. Patent No.
4,229,187) to facilitate t~e capture o~ the particle~.
Ob~ects It is therefore an object oE the present invention to provide a gas filtering apparatus and method for micron sized particles having a unique gas flow path which provides improved par~icle capture by the filter medium~
Further it is an object of the present invention to provide an apparatus and method which generate~ an electrostatic charge in the filter medium which enhances particle capture.
Further still it is an object of tha present invention to l.O provide an appa.ratus which is very compact, and relatively simple and inexpensive to construct. These and other obiects will become increasingly apparent by reference to the fo].lowing description and to the drawingsO
In the DrawincJs LS Figure 1 is a schematic cross-sectional plan view of the apparatus of the present invention particularly illustrating the gas 10w along the surface of a filter medium between the sawtoothed projections defined by a continuous filter bel t o Figure 2 is a schematic ~ront cross-sectional view o the apparatus shown in Figure 1 particularly ilLustrating the positioning of ~he sawtc~othed projections witll ~ails of arrows ~shown by a circle around an x) showing the gas flow along the surfaces o~ sawtoothed ~5 projections supporti.ng the fiLter medium.
Figure 3 is a front .isometric schematic vi~w o the preferred apparatus of t~e present invention showing the preferr~d staggered sawtooth conEiyuration such that the c3a~ p~sses along and between t~e projections and through the fi:Lter medium and particularly showing small partial cross-sections illustrating the location of sensor devicesq Figure 4 is a partial cross-sectional view of On2 sawtoo~hed projection shown in Figure 3 alon~ line 4~4 and particularly showing the ballooning of the filter medium and screened belt due to gas preRsure~
Figure S is a partial sectional view of a porous support~ such as t~e screened belt, ~howing bondi~g oE
intersection~ or ne~u~ between the non-metallic strand~
forming -the screened belt~
6~
Figure SA is a plan partial ~ectional view of a porou~ support, such as for a screened belt, where the nexus of s~rands in one first direction are crimped to restric~ movement of the strands oriented in the other S direction along the strands in the first direc~ion.
Figure SB is an isometric view partial sectioned view showing join;ng of ~he ends of a continuous belt~
Figure 6 is a schematic isometric vl ew showing the staggered positioning of por~ions of th~ outside cas.ing defining the sawtoothed con~iguration of -the projections.
Figures 7, 8 and 9 are graphs showing the performance o various polyester fiber filter media on a polyester strand screen, such as shown in Figure 5, used for the belt in bench testing.
lS General ~escri~tion The invention reiates to a gas borne particle Eiltering apparatus including a filter medium (13) having first and second surfaces (13a and 13b) and a depth (d3 between the surEaces~ an outer casing (10) havin~ an lnlet ~0 and an outlet opening ~11, 12), an endless moveable feed belt (14) in the casing defining rounded tip ~15) multiple sawtoothed cross-sectioned projections alternately pointed in two opposite first and second directions ~16 and 16a) which is located between the inlet anct ou~let openings, ~5 rollers (18) mounted on the ca~ing at the t;ps of the projectlon~ and moveably supporting the fil~er medium and b~Lt w.ith the first surface of khe filter medium adjacent ~he inlet opening and the second surface of the ilter medium in corltact with the belt~ whereill the inlet and the ~() outlet opening~ are separated by the filter medium in the casing or filtratlon and including means for moving the feed belt to remove the ilter medium and mean~ for collecting the re~oved filter medium the improvement which comprises:
~a) clo~ing the projections pointiny in the first direction ~16a) with a first side of the ca~ing (10) such that the projection~ pointlng in the ~econd direction ~16 define the înlet op~nings ~113; and (b) closing the projections pointing in the second direction (16) with a second opposite side of the casing (10) to the first side such that the projections pointing in the first direction (16a) define the outlet openings (12);
Wherein in use gas flow with the particles is along the first surface (13a) of the filter medium towards the sawtoothed projections closed pointed in the second direction (16) on the second side of the casing, then at an angle from the gas flwo along the first surface through the filter medium, then through the feed belt and ten along the second surface (13b) of the filter medium and the belt away from the projections closed in the opposite direction (16a) on the first side of the casing and then out the outlet opening.
The present invention also relates to a method of filtering gas borne particles in a filtering apparatus wherein the inlet and outlet openings (11 and 12) are separated by as filter medium (13) mounted on a porous support (14) for filtration, the improvement which comprises:
providing a small mesh screen as the porous support (14) composed of polymeric strands, the screen having a mesh size of about 6 or greaer in contact with a filter medium (13) wherein upon interaction of the screen in contact with the filter medium during gas flow an electrostatic charge is created which attracts 0.1 micron and larger sized particles to the filter medium for removal from the gas; and flowing a gas through the filter mdium and the screen at a gas velocity of between about 25 and 1000 feet per minute (12.5 to 5000 centimeters per second) at a pressure drop across the filter medium of less than about 2 inches of water (4.9 x 10-3 atmospheres), wherein an increasing percentage of the particles of a particular size are removed as a result of particle loading of the filter medium during filtration.
~s~
The present invention particularly relates to a continuous belt (14) for use in an apparatus or filtering gas borne particles with a EiltQr medium (13~ having a fîrst side ~13a) for receiving~the gas borne particles and S a second side tl3b) wherein the gas is removed without the par~icles, the improvement which comprises:
a continuous belt (14) in the ~orm Qf a small meshed non-metallic screen composed of polymeric strands havin~ nexus (24, 29) which are interbonded or crimped in the form of a con~inuous belt adapted to be in contact with the second side of the fil~er medium (13b) such that during gas flow interaction of the screen in contact with the ~ilter med;um produces an electrostatic charge which attracts 0.1 micron and larger sized particles.
Speci~ic ~ E~
Referring to Figures 1 to 3, the apparatus of the present invention is shown including an outer casin~ 10 having an inlet opening 11 and an outlet opening 1~
Filter medium 13 is mounted in t~e casing 10 on an endless moveahle feed belt 14 which defines rounded tip lS
sawtoothed projec~.ions 16 and l~a between the inlet opening 11 and the outlet opening 120 Roller 18 and 18a moveabl~
support the ~].t 14 ak the t.ips 15 of the projection.s 16 and 16a in the casing 10. ~eturn rollers 1~ and 19a support the retur~ of the belt 14 to the rollers l8a E~''L~ible se~ls 20 are connected to the casing 10 alld are in contact with the f.ilter medium 13 to prov.ide sealing oE the Eilter medium 13 between the inlet opening 11 and the out.l.~t op~ning 120 GeneraLly the filter medium 13 is fed 30 erOm a roll 21 and periodicalL~ removed when spent by particle loadi~g on a ta~eup roll 22 tensioned by a guide 23 outside the casing 10. The inlet opening 11 and the ou~let opening 12 are separated by the filter medium 13 for fi.ltration o the ga~ borne particle~. The rollers 13a and l9a have radially projecting wire brushes which positively en~age and align the belt 14~ The return roller l9a provides the drive means for the belt 14~ The preceding des~ription generally encompasse~ a number of prior art devices.
5~
A unigue feature of th~ present invention includes an inlet opPning 11 and an outlet opening 12 positisned in the casing lO adjacent the sawtoothea proje~t.ions 16 and 16a such that in use the gas flow (shown by arrows in Figures l to 3) is along the surface~ of the sawtoothed projections 16 on a ~irs~ ~ide 13a of the filter medium then at an angle rom the gas flow through the filter medium 13 having a dep~h d and then through the screened feed belt 1~ and along a second surface 13b o the ~ilter medium 13 and belt 14 between the projections 16a and out the outlet opening 12.
An important feature of the present invention is the scxeened eed belt 14. The belt 14 is no~-metallic and can be composed o~ strands interbonded at nexus 24 (or intersections) between the individual strands 25. The polymer is pre~erably a polyester polymer 5uch that the nexus 24 can he heat bonded or solvent welded. In any event, the bonding of the nexus 24 pro~ides sufficient rigidity to the belt 14 to prevent collapse oE the fibers (not shown) of the ilter medium 13 in the spaces 26 between the strands 25 which would restrict gas ~low. The belt 14 can also be constructed of woven polyester monofilaments including warp strands 30 and weft strands 31 oriented generally perpendicular to each other in two directions at ne~us 38, such as shown in Figure 4A which is preferred~ Each wef~ strand 31 has a permanent cri.mp 32 in contact with and overlapping the warp strand 30 at the nexus to prevent the warp strands 30 fro~ll moving relative to each other. This crimp 32 is permanently retained by heatlng the we~t strallds 31 duri.ng weaving. This construction has been found to be more reliab`le than the bonded strands 25 and 24 shown in Figure S. In both instances the edges 33 and 34 of the strands are bound with contact cement to prevent unraveling of the strands 30 and 31. The belt 14 is jointed to make i continuous by i.nterlocking polypropylene spiral coils ~35~ and (36) which in turn are joined together by at least one pol~prQpylene ~ilament 37~ The bonding or crimping also allow3 the belt 14 to be driven and/or aliglled b~ the wire brushes on rollers 18a and l9aO
~ ~35~
The polymer s~rand~ 25 when coupled with a ~uitable filter medium 13 when dry provides ~n ~lectrostatic charge on the filter medium 13 during gas flow which attract~
micron and larger ~ized particles to the filter medium for S removal from the gas~ Preferably the mesh size is about 6 ~36 openings per square inch) or larger and more preferably between 6 and 12 mesh t36 openings per square inch to 144 openings per square inch or between about 6 opening~ to 22 openings per squaxe centimeter~O
The no~-metallic filter medium 13 is of a type which is generalLy known and can include bonded or unbonded flber~, which can be woven or non woven. The non-metallic ~iber~ interact with the belt 14 to create the electrostatic charge. The $ibers can be cellulosic ~paper), glas~ or polymeric including prefera~ly polyester polymer fibers. The medium preferably has a pre~sure drop prior to part.icle loading of between about 0.1 and 2 inches of water (2.4 x 10~4 to 4.9 x 10-3 atmospheres).
The fibers preferably have a dia~leter of between about O..L
7,0 and lO0 mi.cron and the medium 13 has a preferred density between about 0~2 and 8 pounds per cubic foot (3.2 x 10-3 to 6.28 ~ 10-l grams per cubic centimeters).
The polymeric screened belt 14 and medium 13 together provide efficient filtra~ion. Thi~ can be seen ~5 from bench scale te~ts wi~h a polyester screen o Figure 5 a~ the belt 14 with polyester fibers in the medium 13 as shown in Figures 7, 8 and 9. Even better results wer~
a~hieve.d with ~he belt 1~ sho~n in Figure SA.
~he d~kails of the construction of the preferred 3~ appara~us are particularly shown in Figures 20 3 and 4.
The outlet opening 12 incluaes cen~rifugal fans lO0 and optional adjustable louvers lOl to control the volume and velocity of gas flow. The fans 100 are mounted on a shaft 102 with a pulley w~eel 103 which extends outside of the casing lO~ A puLley belt 104 around wheel 103 is po~itioned aroun~ a second pulley 105 on a motor 106 mounted on top oE the casing 10. The fans lO0 preferably pull ~rather than pu~h~ the air through the filter medium 13.
The rollers 1~ are journalled at oppos~e end3 by cap bearings 107 and 107a mounted on the outside of the ca~ing 10 by means of bolt~ 108. The bearing~ 107a adjacent the lower portlon of t~e casing 10 are provided with gears 109 or mounting a drive link chain 110. An idler gear 111 for the chain llB is mounted on the outside of the casing 10~, ~eturn roller~ 19 and l9a are supporte by bearings 112 mounted on the casing 10. On~ return roller l9a i~ provided with a first gear 113 which is driven by a second chain 114 connected to a second gear 115 mounted on a reducing drive 116 and motor 117~ The chains 110 and 114 are driven by the motor 117 and reducing drive 116 combination and provide a means for moving the belt 14 ko remove filter medium 13 from roller 21 for takeup on lS roll 220 ~ollers 18a and l9a have wire brushes 28 and 2g to aid in movement o~ the belt 14 by preventing slippage.
The movement of the belt 14 can be ~anual but this is not preferred.
When the filter medium 13 is filled wi.th particles, the pressure drop across the depth d between the surfaces 13a and 13b becomes too great for effective filtration because of increased pres~ure dropO To provide for automatic changîng o the filter medlum 13, pressure sensing device~ 118 and 119 are provided adjacent the oppo~ite sides 13a and 13b of the ~ilter medium 13 to determine the pressure drop and automatically cycle th~
fil.ter medium 13 suficiently to provide an acceptable pressure drop. The ta~eup roll 22 is provided with a pulle.y wheel 120 and belt 121 driven ~y a secolld pulley wh~l 122 mounked on a reducing drive 123 and powered ~y mot:or 1~4~ The rolls 21 and 22 are positioned on s~lafts L26 and 127 on ar~ 128 and 1~9 Sone side only shown) on the ca~ing 10~ Between pulley wheel 122 and reducing drive 123 is a limiting clutch (not shown) which compensates for 35 the increa~ing diameter of the takeup roll 22 by sl.ip~ing to prevent tearing of the medium 13~ Guide 23 i~ mounted on arms 131 (only one side is shown) on the casing 10.
A unigue feature of th~ present invention includes an inlet opPning 11 and an outlet opening 12 positisned in the casing lO adjacent the sawtoothea proje~t.ions 16 and 16a such that in use the gas flow (shown by arrows in Figures l to 3) is along the surface~ of the sawtoothed projections 16 on a ~irs~ ~ide 13a of the filter medium then at an angle rom the gas flow through the filter medium 13 having a dep~h d and then through the screened feed belt 1~ and along a second surface 13b o the ~ilter medium 13 and belt 14 between the projections 16a and out the outlet opening 12.
An important feature of the present invention is the scxeened eed belt 14. The belt 14 is no~-metallic and can be composed o~ strands interbonded at nexus 24 (or intersections) between the individual strands 25. The polymer is pre~erably a polyester polymer 5uch that the nexus 24 can he heat bonded or solvent welded. In any event, the bonding of the nexus 24 pro~ides sufficient rigidity to the belt 14 to prevent collapse oE the fibers (not shown) of the ilter medium 13 in the spaces 26 between the strands 25 which would restrict gas ~low. The belt 14 can also be constructed of woven polyester monofilaments including warp strands 30 and weft strands 31 oriented generally perpendicular to each other in two directions at ne~us 38, such as shown in Figure 4A which is preferred~ Each wef~ strand 31 has a permanent cri.mp 32 in contact with and overlapping the warp strand 30 at the nexus to prevent the warp strands 30 fro~ll moving relative to each other. This crimp 32 is permanently retained by heatlng the we~t strallds 31 duri.ng weaving. This construction has been found to be more reliab`le than the bonded strands 25 and 24 shown in Figure S. In both instances the edges 33 and 34 of the strands are bound with contact cement to prevent unraveling of the strands 30 and 31. The belt 14 is jointed to make i continuous by i.nterlocking polypropylene spiral coils ~35~ and (36) which in turn are joined together by at least one pol~prQpylene ~ilament 37~ The bonding or crimping also allow3 the belt 14 to be driven and/or aliglled b~ the wire brushes on rollers 18a and l9aO
~ ~35~
The polymer s~rand~ 25 when coupled with a ~uitable filter medium 13 when dry provides ~n ~lectrostatic charge on the filter medium 13 during gas flow which attract~
micron and larger ~ized particles to the filter medium for S removal from the gas~ Preferably the mesh size is about 6 ~36 openings per square inch) or larger and more preferably between 6 and 12 mesh t36 openings per square inch to 144 openings per square inch or between about 6 opening~ to 22 openings per squaxe centimeter~O
The no~-metallic filter medium 13 is of a type which is generalLy known and can include bonded or unbonded flber~, which can be woven or non woven. The non-metallic ~iber~ interact with the belt 14 to create the electrostatic charge. The $ibers can be cellulosic ~paper), glas~ or polymeric including prefera~ly polyester polymer fibers. The medium preferably has a pre~sure drop prior to part.icle loading of between about 0.1 and 2 inches of water (2.4 x 10~4 to 4.9 x 10-3 atmospheres).
The fibers preferably have a dia~leter of between about O..L
7,0 and lO0 mi.cron and the medium 13 has a preferred density between about 0~2 and 8 pounds per cubic foot (3.2 x 10-3 to 6.28 ~ 10-l grams per cubic centimeters).
The polymeric screened belt 14 and medium 13 together provide efficient filtra~ion. Thi~ can be seen ~5 from bench scale te~ts wi~h a polyester screen o Figure 5 a~ the belt 14 with polyester fibers in the medium 13 as shown in Figures 7, 8 and 9. Even better results wer~
a~hieve.d with ~he belt 1~ sho~n in Figure SA.
~he d~kails of the construction of the preferred 3~ appara~us are particularly shown in Figures 20 3 and 4.
The outlet opening 12 incluaes cen~rifugal fans lO0 and optional adjustable louvers lOl to control the volume and velocity of gas flow. The fans 100 are mounted on a shaft 102 with a pulley w~eel 103 which extends outside of the casing lO~ A puLley belt 104 around wheel 103 is po~itioned aroun~ a second pulley 105 on a motor 106 mounted on top oE the casing 10. The fans lO0 preferably pull ~rather than pu~h~ the air through the filter medium 13.
The rollers 1~ are journalled at oppos~e end3 by cap bearings 107 and 107a mounted on the outside of the ca~ing 10 by means of bolt~ 108. The bearing~ 107a adjacent the lower portlon of t~e casing 10 are provided with gears 109 or mounting a drive link chain 110. An idler gear 111 for the chain llB is mounted on the outside of the casing 10~, ~eturn roller~ 19 and l9a are supporte by bearings 112 mounted on the casing 10. On~ return roller l9a i~ provided with a first gear 113 which is driven by a second chain 114 connected to a second gear 115 mounted on a reducing drive 116 and motor 117~ The chains 110 and 114 are driven by the motor 117 and reducing drive 116 combination and provide a means for moving the belt 14 ko remove filter medium 13 from roller 21 for takeup on lS roll 220 ~ollers 18a and l9a have wire brushes 28 and 2g to aid in movement o~ the belt 14 by preventing slippage.
The movement of the belt 14 can be ~anual but this is not preferred.
When the filter medium 13 is filled wi.th particles, the pressure drop across the depth d between the surfaces 13a and 13b becomes too great for effective filtration because of increased pres~ure dropO To provide for automatic changîng o the filter medlum 13, pressure sensing device~ 118 and 119 are provided adjacent the oppo~ite sides 13a and 13b of the ~ilter medium 13 to determine the pressure drop and automatically cycle th~
fil.ter medium 13 suficiently to provide an acceptable pressure drop. The ta~eup roll 22 is provided with a pulle.y wheel 120 and belt 121 driven ~y a secolld pulley wh~l 122 mounked on a reducing drive 123 and powered ~y mot:or 1~4~ The rolls 21 and 22 are positioned on s~lafts L26 and 127 on ar~ 128 and 1~9 Sone side only shown) on the ca~ing 10~ Between pulley wheel 122 and reducing drive 123 is a limiting clutch (not shown) which compensates for 35 the increa~ing diameter of the takeup roll 22 by sl.ip~ing to prevent tearing of the medium 13~ Guide 23 i~ mounted on arms 131 (only one side is shown) on the casing 10.
6 ~ ~
A~ shown in Figure 3 the belt 14 i~ tensioned by a pair of sliding bearing~ 112a using a bolt 132 between spaced parallel platas 133~ U~ing this means, the belt 14 can be trained so tha~ it remains aligned on roller~ 18 and 19~ Alignment of the bearings 107 and gear~ 109 i3 also very important. The belt strands 2~ are interbonded at the nexu~ 24 along the edge 134 (Fi~ure 5) which pxevent~
unravelling of the belt 1~
Figuxes 3 and 4 show angle irons 135 and 136 which are on or paxt o extensions 140 (covering projections l~a) (Figure 6) of casing 10. The irons 135 and 136 form a seal along the edges of the filter medium 13 and belt 140 Op~o~ite and staggered rom the extensions 140 are second extensions 141 (covering proiections 16) on the casing 10 which are mating in shape to the shape o~ the extensions 140 as shown in Figure 6~ Thus adjacent the inlet opaning 11 the extensions ].40 are solid and on the other side at the outlet opening 12 the corresponding space is open as shown în Figure 4 angled members 137 support the belt 1~ to ZO prevent leakage between the inlet opening 11 an~ outlet opening 12.
As shown in Figure 4 the belt 14 and ;1ter medium 13 are ballooned in the direction o~ air flow shown by the arrow~. Figure 4 is sightly exaggerated; however, it does show that both the medium 13 and belt 14 stretch under the gas ~ressure. The stretching allows th~ gas 10w across th~ sur~ac~ ~o flutter the media ~3 against the belt 14 together to create an electrostatic charge which attracts the small~st sized particles. Thus ~he configuration of ~0 Figllr~ 4 is preferred~
Operation In opexation, the belt 14 and filter medium 13 are trained on the rollers 18 and 19 as shown in Figure 2 by means o ~earings 107 and 112. Motor 106 is ~tarted to rotate the fans 100. ~ouvers 101 are adjusted to the proper gas flow~ The particle (lîquid or solid) laden gas enters the lnlet opening 11~ pas~es across a first surf~ce 13a between the projections 16a and through the filter 13 causin~ the filter 13 and belt 14 to balloon and to flutter ~9S~
in contact with ~ach other causing an electro~tatic char~e which attract~ the particles and removes the~ from the ga~
and then the cleansed gas passes through the second surface 13b, through the belt 14~ across the belt 24 and out the 5 outlet opening 12 between the extensions 141 as shown in Figure 6. The casing 10 includes conduit e~tension lOa for the fans 100 and conduit extension lOb for focussing the air away from the outlet opening 12. Upon max;mum loading of partic~es in the filter medium 13f the sensor devices 118 and 119 detect the increased pressure drop acros~ the medium 13 and signals mo~ors 117 and 124 to operate. The medium 13 is then conveyed from th~ dispensing roller 21 with the belt 14 to the takeup roller 22 until the change in pressure is reduced to an accep-table levelO In most L5 instances this will leave some particle loaded medium 13 in the filter ~ath. The cycle is repeated periodically as particle loading progresses.
The apparatus is usually mounted adjacent a ceiling in a shop or actory so ~hat clean air is ~irculated throughout the shop. The unit is designed to recycle heated or cooled air and thus produces considerable energy savings 'L'he apparatus can handle as low as 2000 cfm up to 200,000 cm (942 to 94,200 liters per s~cond~ of gas with ease and wilL remove welding smoke or oil mist in air ;n the .5 fraction of a micron si2e or smaller (0.1 micron) and p~rticle.s up to or above 100 mic.rons~ The pressure drop across the medium 13 i5 gerlerally between 1 and 2 inches of w~ter (2.4 x 10-3 to 4.9 x 10-3 atmospheres) at about 50 to sao feet per minute (~5 to 250 centimeters per second) when ~0 the Eilter medium 13 is clean. The apparatus thus provides energy e~iciency and polLution reduction.
A~ shown in Figure 3 the belt 14 i~ tensioned by a pair of sliding bearing~ 112a using a bolt 132 between spaced parallel platas 133~ U~ing this means, the belt 14 can be trained so tha~ it remains aligned on roller~ 18 and 19~ Alignment of the bearings 107 and gear~ 109 i3 also very important. The belt strands 2~ are interbonded at the nexu~ 24 along the edge 134 (Fi~ure 5) which pxevent~
unravelling of the belt 1~
Figuxes 3 and 4 show angle irons 135 and 136 which are on or paxt o extensions 140 (covering projections l~a) (Figure 6) of casing 10. The irons 135 and 136 form a seal along the edges of the filter medium 13 and belt 140 Op~o~ite and staggered rom the extensions 140 are second extensions 141 (covering proiections 16) on the casing 10 which are mating in shape to the shape o~ the extensions 140 as shown in Figure 6~ Thus adjacent the inlet opaning 11 the extensions ].40 are solid and on the other side at the outlet opening 12 the corresponding space is open as shown în Figure 4 angled members 137 support the belt 1~ to ZO prevent leakage between the inlet opening 11 an~ outlet opening 12.
As shown in Figure 4 the belt 14 and ;1ter medium 13 are ballooned in the direction o~ air flow shown by the arrow~. Figure 4 is sightly exaggerated; however, it does show that both the medium 13 and belt 14 stretch under the gas ~ressure. The stretching allows th~ gas 10w across th~ sur~ac~ ~o flutter the media ~3 against the belt 14 together to create an electrostatic charge which attracts the small~st sized particles. Thus ~he configuration of ~0 Figllr~ 4 is preferred~
Operation In opexation, the belt 14 and filter medium 13 are trained on the rollers 18 and 19 as shown in Figure 2 by means o ~earings 107 and 112. Motor 106 is ~tarted to rotate the fans 100. ~ouvers 101 are adjusted to the proper gas flow~ The particle (lîquid or solid) laden gas enters the lnlet opening 11~ pas~es across a first surf~ce 13a between the projections 16a and through the filter 13 causin~ the filter 13 and belt 14 to balloon and to flutter ~9S~
in contact with ~ach other causing an electro~tatic char~e which attract~ the particles and removes the~ from the ga~
and then the cleansed gas passes through the second surface 13b, through the belt 14~ across the belt 24 and out the 5 outlet opening 12 between the extensions 141 as shown in Figure 6. The casing 10 includes conduit e~tension lOa for the fans 100 and conduit extension lOb for focussing the air away from the outlet opening 12. Upon max;mum loading of partic~es in the filter medium 13f the sensor devices 118 and 119 detect the increased pressure drop acros~ the medium 13 and signals mo~ors 117 and 124 to operate. The medium 13 is then conveyed from th~ dispensing roller 21 with the belt 14 to the takeup roller 22 until the change in pressure is reduced to an accep-table levelO In most L5 instances this will leave some particle loaded medium 13 in the filter ~ath. The cycle is repeated periodically as particle loading progresses.
The apparatus is usually mounted adjacent a ceiling in a shop or actory so ~hat clean air is ~irculated throughout the shop. The unit is designed to recycle heated or cooled air and thus produces considerable energy savings 'L'he apparatus can handle as low as 2000 cfm up to 200,000 cm (942 to 94,200 liters per s~cond~ of gas with ease and wilL remove welding smoke or oil mist in air ;n the .5 fraction of a micron si2e or smaller (0.1 micron) and p~rticle.s up to or above 100 mic.rons~ The pressure drop across the medium 13 i5 gerlerally between 1 and 2 inches of w~ter (2.4 x 10-3 to 4.9 x 10-3 atmospheres) at about 50 to sao feet per minute (~5 to 250 centimeters per second) when ~0 the Eilter medium 13 is clean. The apparatus thus provides energy e~iciency and polLution reduction.
Claims
In a gas borne particle filtering apparatus including a non-metallic filter medium (13) having first and second surfaces (13a and 13b) and a depth (d) between the surfaces, an outer casing (10) having an inlet and an outlet opening (11, 12), an endless moveable feed belt (14) in the casing defining rounded tip (15) multiple sawtoothed cross-sectioned projections alternately pointed in two opposite first and second directions (16 and 16a) which feed belt is located between the inlet and outlet openings, rollers (18) mounted on the casing at the tips of the projections and moveably supporting the filter medium and belt with the first surface of the filter medium adjacent the inlet opening and the second surface of the filter medium in contact with the belt, wherein the inlet and the outlet openings are separated by the filter medium in the casing for filtration and including means for moving the feed belt to remove the filter medium and means for collecting the removed filter medium, the improvement which comprises:
(a) closing the projections pointing in the first direction (16a) with a first side of the casing (10) such that the projections pointing in the second direction (16) define the inlet openings (11); and (b) closing the projections pointing in the second direction (16) with a second opposite side of the casing (10) to the first side such that the projections pointing in the first direction (16a) define the outlet openings (12); and (c) a small mesh, non-metallic screen of crimped interwoven strands perpendicular to the direction of movement of the belt as the feed belt (14);
wherein in use gas flow with the particles is along the first surface (13a) of the filter medium towards the sawtoothed projections which are closed in the second direction (16) on the second side of the casing, then at an angle from the gas flow along the first surface through the filter medium, then through the feed belt and then along the second surface (13b) of the filter medium and the belt away from the projections closed in the first direction (l6a) on the first side of the casing and then out the outlet opening.
The filtering apparatus of Claim 1 wherein the screen is composed of polymeric strands and wherein fibers forming the filter medium are composed of a polymer which interacts with the screen during gas flow to create an electrostatic charge on the filter medium which attracts micron and larger sized particles to the filter medium for removal from the gas.
The filtering apparatus of Claim 2 wherein screen has strands which are a polyester polymer.
The apparatus of Claim 1 wherein the screen is about 6 to 12 mesh.
The apparatus of Claim 1 wherein the screen has strands which are composed of a polyester polymer having a mesh size of about 6 to 12.
The filtering apparatus of Claim 1 wherein a fan means for producing the gas flow through the filter medium is provided in a conduit adjacent to the outlet opening.
The filtering apparatus of Claim 1 wherein the filter medium is composed of fibers which have a density and a depth which prior to particle loading from use produces a pressure drop across the medium of between about 0.1 and 2 inches of water.
The apparatus of Claim 1 wherein the filter medium is composed of polymeric fibers having a diameter between about 0.1 and 100 micron and a density between about 0.2 and 8 pounds per cubic foot.
The apparatus of Claim 8 wherein the polymeric fibers are a polyester polymer.
The apparatus of Claim 1 wherein the screen has strands composed of a polyester polymer and the belt has a mesh size of about 6 or larger and wherein the filter medium prior to particle. loading from use has a pressure drop across the depth of between about 0.1 and 2 inches of water and is composed primarily of polymeric fibers having a diameter of between about 0.1 and 100 micron and having a density between about 0.2 and 8 pounds per cubic foot.
The apparatus of Claim 1 mounted such that the projections are pointed upwardly and downwardly and such that the gas flow is horizontal through the apparatus.
In a gas borne particle filtering apparatus including a filter medium (13) having first and second surfaces (13a and 13b) and a depth (d) between the surfaces, an outer casing (10) having an inlet and an outlet opening (11, 12), an endless moveable feed belt (143 in the casing defining rounded tip (15) multiple sawtoothed cross-sectioned projections alternately pointed in two opposite first and second directions (16 and 16a) which is located between the inlet and outlet openings, rollers (18 mounted on the casing at the tips of the projections and moveably supporting the filter medium and belt with the first surface of the filter medium adjacent the inlet opening and the second surface of the filter medium in contact with the belt, wherein the inlet and the outlet openings are separated by the filter medium in the casing for filtration and including means for moving the feed belt to remove the filter medium and means for collecting the removed filter medium the improvement which comprises:
(a) closing the projections pointing in the first direction (16a) with a first side of the casing (10) such that the projections pointing in the second direction (16) define the inlet opening (11);
(b) closing the projections pointing in the second direction (16) with a second opposite side of the casing (10) to the first side such that the projections painting in the first direction (16a) define the outlet openings (12);
wherein in use gas flow with the particles is along the first surface (13a) of the filter medium towards the sawtoothed projections closed pointed in the second direction (16) on the second side of the casing, then at an angle from the gas flow along the first surface through the filter medium, then through the feed belt and then along the second surface (13b) of the filter medium and the belt away from the projections closed in the opposite direction (16a) on the first side of the casing and then out the outlet opening and wherein the filter medium is composed of interwoven strands which are crimped perpendicular to the direction of movement of the belt.
The apparatus of Claim 12 mounted such that the gas flow is horizontal through the inlet and outlet openings.
The apparatus of Claim 12 wherein a fan means for producing gas flow through the filter medium is provided in a conduit adjacent to and attached to the outlet opening.
The apparatus of Claim 12 wherein the filter medium removes particles having a size between 0.1 and 20 microns.
In a method of filtering gas borne particles in a filtering apparatus wherein the inlet and outlet openings (11 and 12) are separated by a filter medium (13) mounted on a porous support (14) for filtration, the improvement which comprises:
(a) providing a small mesh screen as the porous support (14) composed of polymeric strands, the screen having a mesh size of about 6 or greater, in contact with a filter medium (13) wherein upon interaction of the screen in contact with the filter medium during gas flow an electrostatic charge is created which attracts 0.1 micron and larger sized particles to the filter medium for removal from the gas; and (b) flowing a gas through the filter medium and then the screen at a gas velocity of between about 25 and 1000 feet per minute at a pressure drop across the filter medium of less than about 2 inches of water, wherein an increasing percentage of the particles of a particular size are removed as a result of particle loading of the filter medium during filtration.
The method of Claim 16 wherein the filter medium is composed of polymeric fibers having a diameter of between about 0.1 and 100 microns.
The method of Claim 16 wherein the filter medium is composed of polyester polymer fibers and the filter material has a density of between about 0.2 and 8 pounds per cubic foot.
The method of claim 16 wherein the pressure drop is between about 1 and 2 inches of water and wherein the gas velocity is between about 50 and 500 feet per minute.
The method of Claim 16 wherein the gas is air containing welding smoke which is removed during the filtration.
The method of Claim 16 wherein the screen has a porosity of between about 6 and 12 mesh.
The method of Claim 21 wherein the screen is composed of polyester polymer strands.
The method of Claim 16 wherein the strands of the porous support are woven (25, 30, 31) to provide nexus of overlapping strands oriented generally perpendicular to each other in two directions.
The method of Claim 23 wherein the nexus of the strand (31) in at least one first direction are crimped (32) to restrict movement of the strands (30) oriented in the other direction along the strands in the first direction.
The method of Claim 24 wherein the porous support is in the form of a moveable belt (14) with the crimped strands along the length of the belt.
The method of Claim 23 wherein the nexus 24 are interbonded.
(a) closing the projections pointing in the first direction (16a) with a first side of the casing (10) such that the projections pointing in the second direction (16) define the inlet openings (11); and (b) closing the projections pointing in the second direction (16) with a second opposite side of the casing (10) to the first side such that the projections pointing in the first direction (16a) define the outlet openings (12); and (c) a small mesh, non-metallic screen of crimped interwoven strands perpendicular to the direction of movement of the belt as the feed belt (14);
wherein in use gas flow with the particles is along the first surface (13a) of the filter medium towards the sawtoothed projections which are closed in the second direction (16) on the second side of the casing, then at an angle from the gas flow along the first surface through the filter medium, then through the feed belt and then along the second surface (13b) of the filter medium and the belt away from the projections closed in the first direction (l6a) on the first side of the casing and then out the outlet opening.
The filtering apparatus of Claim 1 wherein the screen is composed of polymeric strands and wherein fibers forming the filter medium are composed of a polymer which interacts with the screen during gas flow to create an electrostatic charge on the filter medium which attracts micron and larger sized particles to the filter medium for removal from the gas.
The filtering apparatus of Claim 2 wherein screen has strands which are a polyester polymer.
The apparatus of Claim 1 wherein the screen is about 6 to 12 mesh.
The apparatus of Claim 1 wherein the screen has strands which are composed of a polyester polymer having a mesh size of about 6 to 12.
The filtering apparatus of Claim 1 wherein a fan means for producing the gas flow through the filter medium is provided in a conduit adjacent to the outlet opening.
The filtering apparatus of Claim 1 wherein the filter medium is composed of fibers which have a density and a depth which prior to particle loading from use produces a pressure drop across the medium of between about 0.1 and 2 inches of water.
The apparatus of Claim 1 wherein the filter medium is composed of polymeric fibers having a diameter between about 0.1 and 100 micron and a density between about 0.2 and 8 pounds per cubic foot.
The apparatus of Claim 8 wherein the polymeric fibers are a polyester polymer.
The apparatus of Claim 1 wherein the screen has strands composed of a polyester polymer and the belt has a mesh size of about 6 or larger and wherein the filter medium prior to particle. loading from use has a pressure drop across the depth of between about 0.1 and 2 inches of water and is composed primarily of polymeric fibers having a diameter of between about 0.1 and 100 micron and having a density between about 0.2 and 8 pounds per cubic foot.
The apparatus of Claim 1 mounted such that the projections are pointed upwardly and downwardly and such that the gas flow is horizontal through the apparatus.
In a gas borne particle filtering apparatus including a filter medium (13) having first and second surfaces (13a and 13b) and a depth (d) between the surfaces, an outer casing (10) having an inlet and an outlet opening (11, 12), an endless moveable feed belt (143 in the casing defining rounded tip (15) multiple sawtoothed cross-sectioned projections alternately pointed in two opposite first and second directions (16 and 16a) which is located between the inlet and outlet openings, rollers (18 mounted on the casing at the tips of the projections and moveably supporting the filter medium and belt with the first surface of the filter medium adjacent the inlet opening and the second surface of the filter medium in contact with the belt, wherein the inlet and the outlet openings are separated by the filter medium in the casing for filtration and including means for moving the feed belt to remove the filter medium and means for collecting the removed filter medium the improvement which comprises:
(a) closing the projections pointing in the first direction (16a) with a first side of the casing (10) such that the projections pointing in the second direction (16) define the inlet opening (11);
(b) closing the projections pointing in the second direction (16) with a second opposite side of the casing (10) to the first side such that the projections painting in the first direction (16a) define the outlet openings (12);
wherein in use gas flow with the particles is along the first surface (13a) of the filter medium towards the sawtoothed projections closed pointed in the second direction (16) on the second side of the casing, then at an angle from the gas flow along the first surface through the filter medium, then through the feed belt and then along the second surface (13b) of the filter medium and the belt away from the projections closed in the opposite direction (16a) on the first side of the casing and then out the outlet opening and wherein the filter medium is composed of interwoven strands which are crimped perpendicular to the direction of movement of the belt.
The apparatus of Claim 12 mounted such that the gas flow is horizontal through the inlet and outlet openings.
The apparatus of Claim 12 wherein a fan means for producing gas flow through the filter medium is provided in a conduit adjacent to and attached to the outlet opening.
The apparatus of Claim 12 wherein the filter medium removes particles having a size between 0.1 and 20 microns.
In a method of filtering gas borne particles in a filtering apparatus wherein the inlet and outlet openings (11 and 12) are separated by a filter medium (13) mounted on a porous support (14) for filtration, the improvement which comprises:
(a) providing a small mesh screen as the porous support (14) composed of polymeric strands, the screen having a mesh size of about 6 or greater, in contact with a filter medium (13) wherein upon interaction of the screen in contact with the filter medium during gas flow an electrostatic charge is created which attracts 0.1 micron and larger sized particles to the filter medium for removal from the gas; and (b) flowing a gas through the filter medium and then the screen at a gas velocity of between about 25 and 1000 feet per minute at a pressure drop across the filter medium of less than about 2 inches of water, wherein an increasing percentage of the particles of a particular size are removed as a result of particle loading of the filter medium during filtration.
The method of Claim 16 wherein the filter medium is composed of polymeric fibers having a diameter of between about 0.1 and 100 microns.
The method of Claim 16 wherein the filter medium is composed of polyester polymer fibers and the filter material has a density of between about 0.2 and 8 pounds per cubic foot.
The method of claim 16 wherein the pressure drop is between about 1 and 2 inches of water and wherein the gas velocity is between about 50 and 500 feet per minute.
The method of Claim 16 wherein the gas is air containing welding smoke which is removed during the filtration.
The method of Claim 16 wherein the screen has a porosity of between about 6 and 12 mesh.
The method of Claim 21 wherein the screen is composed of polyester polymer strands.
The method of Claim 16 wherein the strands of the porous support are woven (25, 30, 31) to provide nexus of overlapping strands oriented generally perpendicular to each other in two directions.
The method of Claim 23 wherein the nexus of the strand (31) in at least one first direction are crimped (32) to restrict movement of the strands (30) oriented in the other direction along the strands in the first direction.
The method of Claim 24 wherein the porous support is in the form of a moveable belt (14) with the crimped strands along the length of the belt.
The method of Claim 23 wherein the nexus 24 are interbonded.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/440,171 US4501598A (en) | 1981-11-09 | 1982-11-08 | Gas borne particle filtering method |
| US440,171 | 1982-11-08 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1195622A true CA1195622A (en) | 1985-10-22 |
Family
ID=23747733
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000429409A Expired CA1195622A (en) | 1982-11-08 | 1983-06-01 | Gas borne particle filtering method |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1195622A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115846050A (en) * | 2023-02-02 | 2023-03-28 | 山东岱荣节能环保科技有限公司 | Oil mist waste gas waste heat purification device |
-
1983
- 1983-06-01 CA CA000429409A patent/CA1195622A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115846050A (en) * | 2023-02-02 | 2023-03-28 | 山东岱荣节能环保科技有限公司 | Oil mist waste gas waste heat purification device |
| CN115846050B (en) * | 2023-02-02 | 2023-05-02 | 山东岱荣节能环保科技有限公司 | Oil mist waste gas waste heat purification device |
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