CA1080638A - Filters for vehicle occupant restraint system fluid supplies - Google Patents
Filters for vehicle occupant restraint system fluid suppliesInfo
- Publication number
- CA1080638A CA1080638A CA270,328A CA270328A CA1080638A CA 1080638 A CA1080638 A CA 1080638A CA 270328 A CA270328 A CA 270328A CA 1080638 A CA1080638 A CA 1080638A
- Authority
- CA
- Canada
- Prior art keywords
- filter
- filter material
- layers
- layer
- porosity
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
- B60R21/02—Occupant safety arrangements or fittings, e.g. crash pads
- B60R21/16—Inflatable occupant restraints or confinements designed to inflate upon impact or impending impact, e.g. air bags
- B60R21/26—Inflatable occupant restraints or confinements designed to inflate upon impact or impending impact, e.g. air bags characterised by the inflation fluid source or means to control inflation fluid flow
- B60R21/264—Inflatable occupant restraints or confinements designed to inflate upon impact or impending impact, e.g. air bags characterised by the inflation fluid source or means to control inflation fluid flow using instantaneous generation of gas, e.g. pyrotechnic
- B60R21/2644—Inflatable occupant restraints or confinements designed to inflate upon impact or impending impact, e.g. air bags characterised by the inflation fluid source or means to control inflation fluid flow using instantaneous generation of gas, e.g. pyrotechnic using only solid reacting substances, e.g. pellets, powder
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D39/00—Filtering material for liquid or gaseous fluids
- B01D39/14—Other self-supporting filtering material ; Other filtering material
- B01D39/20—Other self-supporting filtering material ; Other filtering material of inorganic material, e.g. asbestos paper, metallic filtering material of non-woven wires
- B01D39/2003—Glass or glassy material
- B01D39/2017—Glass or glassy material the material being filamentary or fibrous
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D39/00—Filtering material for liquid or gaseous fluids
- B01D39/14—Other self-supporting filtering material ; Other filtering material
- B01D39/20—Other self-supporting filtering material ; Other filtering material of inorganic material, e.g. asbestos paper, metallic filtering material of non-woven wires
- B01D39/2027—Metallic material
- B01D39/2041—Metallic material the material being filamentary or fibrous
-
- 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
- B01D46/24—Particle separators, e.g. dust precipitators, using rigid hollow filter bodies
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F42—AMMUNITION; BLASTING
- F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
- F42B3/00—Blasting cartridges, i.e. case and explosive
- F42B3/04—Blasting cartridges, i.e. case and explosive for producing gas under pressure
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2275/00—Filter media structures for filters specially adapted for separating dispersed particles from gases or vapours
- B01D2275/10—Multiple layers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2279/00—Filters adapted for separating dispersed particles from gases or vapours specially modified for specific uses
- B01D2279/10—Filters adapted for separating dispersed particles from gases or vapours specially modified for specific uses for air bags, e.g. inflators therefor
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Mechanical Engineering (AREA)
- Filtering Materials (AREA)
- Air Bags (AREA)
- Filtering Of Dispersed Particles In Gases (AREA)
Abstract
ABSTRACT
A filter assembly is provided for fluid supplies for vehicle occupant restraint systems which employ a combustible gas generator to inflate a confinement upon the occurrence of a collision. The filter assembly includes two sets of layers of porous filter material.
One set includes a plurality of layers of fibrous filter material of relatively high porosity such as steel wool. The other set includes a plurality of layers of filter material arranged in order of descending porosity between the gas generator and the confinement and positioned intermediate the layers of the former set. Each of the layers of this other set is of substantially lower porosity than those adjacent layers of the former set.
A filter assembly is provided for fluid supplies for vehicle occupant restraint systems which employ a combustible gas generator to inflate a confinement upon the occurrence of a collision. The filter assembly includes two sets of layers of porous filter material.
One set includes a plurality of layers of fibrous filter material of relatively high porosity such as steel wool. The other set includes a plurality of layers of filter material arranged in order of descending porosity between the gas generator and the confinement and positioned intermediate the layers of the former set. Each of the layers of this other set is of substantially lower porosity than those adjacent layers of the former set.
Description
The presellt invention relates to filters for fluid supplles of vehicle occupant restraint systems employing combustible gas generators.
Multilayer filter assemblies for vehicle occupant restraint systems employing combustible gas generators are known in the prior art. "Exemplary of this art are filters shown in applicant's U.S. Patent number 4,012,211, issued March 15, 197~, and entitled Filter For Occupant Restraint System Fluid Supply."
Certain disadvantages have been noted, however, in the use of such filter assemblies.
One of these is the tendency of solid contaminants to concentrate in certain areas of the filter and there-after to burn through the filter layers. This tendency is commonly referred to as "pinholding".
Another disadvantage is the tendency of such filters to permit "channelling", that is, bypassing of one or more filter layers by a portion of the flowing gas due to inadequate support of one or more of the layers when intermediate support members are not used or are ineffective.
Still another disadvantage lies in the fact that the prior art filters tend to have high heat capacity, necessitating the use of large amounts of combustible material to effect inflation of the confinement.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved filter assembly for vehicle occupant restraint systems employing combustible gas generators which minimizes the concentration of contaminants passing through the filter.
It is another object to provide a filter which minimizes the tendency of combustion aases to bypass the ,~
J`~J
la~ 3~
filter.
It is yet another object to provide a filter whose heat capacity tends to permit the use of a minimum amount of combustion material fox effecting inflation.
According to the present invention there is provided a filter for filtration of contaminants produced in the gas flow of a gas generator of the type used for inflation in vehicle occupant restraint systems. The filter includes a plurality of layers of a first filter material, the first filter material being fibrous and porous, each of the layers of the first filter material defining a plenum zone for dispersing and filtering con-taminants contained in the gas flow throughout the plenum zone. The filter further includes a plurality of layers of second filter material, the second filter material being fibrous and having a porosity substantially less than the first filter material, the plurality of first and second filter material layers being disposed in alternating arrangement such that each layer of the second filter material is bounded on either side thereof by a layer of the first filtex material.
The above objects and features, as well as others, will be apparent to those skilled in the art of filters for occupant restraint systems employing combustible gas generators upon reading the accompanying detailed description with reference to the drawlngs in which:
i3#
Figure 1 is a fragmentary cross sectional view of a fluid supply incorporating the invention filter;
Figure 2 is an exploded fragmentary cross sectional view of the filter assembly of the present invention; and Figure 3 is a cross sectional view of the invention filter assembly taken along line 3-3 of Figure 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
. ~
Referring now to Figure 1, a fluid supply 10 is illustrated as including a cylindrical housing assembly 12, an igniter assembly 14, means 16 for generating gas for inflation through combustion, and a filter assembly 18 dis-posed between the gas generating means 16 and the housing 12.
It should be understood, however, that the illustration of the filter assembly 18 as employed in the cylindrically housed fluid supply of the drawings is not intended to be limiting.
The applicability of the invention filter to other fluid supplied (See, e.g.-, the flat pack fluid supply disclosed by applicat-~on U.S. Patent No. 4,017,100, issued April 12, 1977 and assigned to the assignee of the present invention.) will be apparent as the description continues.
The housing assembly 12 includes a base portion 20, a fluid directing portion 22, and an end cap 24. Base portion 20 is preferably secured to one end of the fluid directing portion 22 by welding or the like as illustrated at 26 and carries one end of the igniter assembly 14 in a centrally --located bore 28 closed by a plug 30.
; Fluid directing portion 22 defines a generally cylindrical shell through which a multiplicity o axially and circumferentially spaced ports 32 are formed.
The end of fluid directing portion 22 opposite ..
~ -3-, the base portion 20 is illustrated as being internally threaded at 36 to receive the end cap 24 which is externally threaded.
The igniter assembly 14 is threadedly received in a centrally located internally threaded bore 38 in the end cap 24, The igniter assembly 14 may be of any known design but is illustrated in Figure 1 as being of the type including electrical leads 140 for receiving a signal from a crash sensor (not shown) upon the occurrence of a collision.
The gas generating means 16 comprises suitable combustible material filling the space between the igniter assembly 14 and the filter assembly 18. While other com-bustible materials may be chosen, that having a granular solid form and composition as disclosed by applicant in Canadian Patent ~pplication Serial No. 240,246, filed November 24, 1975 and assigned to the assignee of the present invention is preferred. The particular arrangement of the gas generating material is preferably as set forth in the above referenced concurrent application of Applicant G. W.
Goetz.
The filter assembly 18 is formed in a substantially cylindrical configuration as may best be seen in the Figures 1 and 3 and is illustrated as including a relatively thin perforated plate 40 having formed through it a plurality of axially and radially spaced holes 42, an inner support screen 44, first and second outer support screens 46 and 48, respectively, and a plurality of layers of deformable - fibrous filter material 50.
. The components of the filter assembly 18 are arranged generally in the order of their decreasing porosity .
: ~ -4-., .
in the flow direction as taught in the U.S. Patent No.
4,017,100 and assigned to the assignee of the present invention. Inner support screen 44 is adjacent the perforated plate 40 and has a relatively high porosity and National Bureau of Standards mesh number, U.S. Standard testing sieve, market grade or equivalent such as No. 24.
First outer support screen 46 is also highly porous with a National Bureau of Standards mesh number such as #24.
Second outer support screen 48 is formed from a still more porous screen fabric such as No. 8 mesh.
The layers 50 of filter material are illustrated here as being arranged to effect filtration of the products of combustion of the gas generating means 16 while preventing clogging, channelling, or pin holing. Specifically, the layers 50 of deformable fibrous filter material, whi~h are supported by the screens 44, 46 and 48, are arranged as two sets of layers. The layers 52 and 54 may be formed of fibers having diameters in the range of about 1 to about 20 microns. In the preferred~embodiment one set comprises layers 52, 54 of high temperature washed fiberglas having fiber diameters in the range of two to ten microns such as is manufactured and sold under the trade mark "Lo Con" by Carborundum Corp., P.O. Box 339, Niagra Falls, New York 14302.
It will be clear to those skilled in the art, however, that other fibrous filter materials including those employing metallic fibers, could be used providing the layers are arranged to effect generally finer filtration in the downstream flow direction.
The other set comprises layers 51, 53, 55 of steel ~ --5--l~U~i3~
wool, preferably but not necessarily no. 0000 steel wool, which is substantially more porous than the washed fiberglas.
The layers 51, 53 and 55 may consist of fibers having diameters in the range of about 50 to about 150 microns.
As can best be seen in Fig. 2, the steel wool layers 51, 53, 55 are interdigitated with respect to the fiberglas layers 52,~54, with layer 51 being placed adjacent the inner support screen 44 and layer 55 being placed adjacent first outer support screen 46.
It is this arrangement of the layers that the present invention departs from the teaching of previously - referenced U.S. Patent No. 4,017,100. The layer arrangement described presents a filter assembly of alternating porosity to the gas flowing from the gas generating means 16 outward through the fluid directing portion 22. The steel wool layers 51, 53, 55 serve as,intermediate plenums, provide - additional support for the adjacent filter layers, and redistribute contaminants. The redistribution tends to elminate "pinholding". The additional support tends to --prevent channelling; and the provision of intermediate plenum space tends to reduce the overall heat capacity of the filter through increased filter efficiency which is defined as ~log particulates passed~heat capacity). This last effect in the preferred embodiment creates a warmer gas flow and - consequently a greater volume flow per mass of propellant, allowing use of less propellant material for inflation.
It should be clear, however, that improved filter efficiency might also be utilized to remove more solid product.s of combustion with a lower resulting gas temperature.
Many modifications of the array of filter layers ., ,. ~
3~
are possible without departing from the spirit of invention.
For example, more layers of filter and plenum material may be used, more than one plenum layer may be positioned adjacent the inner support screen 44 or different filter or plenum materials may be utilized. One specific substitution that has been successfully made is a layer of approximately 1.5 micron fiber high filtration paper such as is sold by Carborundum Corporation under the Registered Trade Mark HI-FI 660-FH PAPER.
FABRICATION AND INSTALLATION OF THE FILTER ASSEMBLY
To form the filter assembly 18 in the embodiment illustrated, the support screens 44, 46, and 48, and the layers 50 of deformable fibrous filter material are first fabricated substantially rectangular sheets of equal length denoted by reference letter -L- in Figure 2 and having widths increasing proportionally with their distance from the central axis of the housing assembly 12, as viewed in Figure 1.
The sheet forming second outer support screen 48 includes an inwardly extending flange portion 58 at one end to facilitate insertion into the housing assembly 12.
w~ --'I'he she~t forming the first outer support screen 46 includcs inwardly extending flange portions 60 on each longitudinal edge to effect closure of the filter assembly.
' After fabrication the sheets are arranged in a rlat 5l pack shown in Figure 2 and placed in a press wherein a high compressive force is applied.
Referring now to Figure 3, the resulting compressed I rectangular filter pack is subsequently formed by rolling or I like process into a resilient cylinder having a transverse 10' dimension, in its radially compressed condition, less than .he mer diameter 68 of the housing assembly 12. The barrier effect of the flange portions 60 tosether with the main-~! taining of a uniform thickness in the fabrication of the ¦, filter back insures uniform distribution of the compressed 15~I filter material.
'I ~ The perforated plate 40, which may be fabricatedfirst as a rectangular sheet, is rolled or otherwise processed to form a cylinder (as may best be seen in Figure 4) whose - , longitudinal seam 64 is closed by fixïng a thin plate 66 to the inner diameter 70 of the perforated plate 40 at the seam 64 by weldments 72 or the like and whose inner diameter 70 is sized to receive th~ gas generating means 16.
- To prepare the filter assembly 18 for installatior. in ~ !, the typical radial flow generator housing 12 the perforated ,1 25ll plate 40 is first placed within the resilient cylinder 61.
The cylinder 61 is then radially loaded by means of a fixture (not snown) which is configured to allow sliding . . ~
-8- , ;h movemcllt of the cylinder 61 with respect thereto. The longitudinal axis of cylinder 61 is then aligned with the ~ longitudinal aY.is of the housing 12. An axial load is then ; ~ applied to the filter assembly 18 to slide it out of the 5,~ fixture into the housing 12, with inwardly extending flange portion 58 of second outer screen 48 providing a relatively , smooth leading edge to facilitate insertion. In order to ~~ further aid insertion, the housing 12 may be vibrated to ,' effectively reduce the frictional forces acting between the 10; filter assembly 18 and the inner surface of housing 12.
i When installed as described in Figure 1 the filter '" assembly 18 effects filtration of the products of combustion il of the gas generating means 16 which are released to flow ,' outward through fluid directing passages 32 in the housing 12 5;¦ when the gas generating means 16 is actuated by the igniter assembly 14 upon the occurrence of a collision. Gaseous products flow outward from the gas generating means 16 through holes 42 in the perforated plate 40, bypassing being prevented 1, by the plate 66. Filtration of the solid products of the combustion is effected during passage through the screen 44, and the layers of filter material 50. Bypassing of these " portions of the filter assembly 18 is prevented through the ',j positioning of the seam 62.
, Although the filter assembly of the present invention has 25~ been described in only certain embodiments, o.her embodiments and modifications may be constructed without departing from the spirit of the invention as presently claimed.
.
,~
Multilayer filter assemblies for vehicle occupant restraint systems employing combustible gas generators are known in the prior art. "Exemplary of this art are filters shown in applicant's U.S. Patent number 4,012,211, issued March 15, 197~, and entitled Filter For Occupant Restraint System Fluid Supply."
Certain disadvantages have been noted, however, in the use of such filter assemblies.
One of these is the tendency of solid contaminants to concentrate in certain areas of the filter and there-after to burn through the filter layers. This tendency is commonly referred to as "pinholding".
Another disadvantage is the tendency of such filters to permit "channelling", that is, bypassing of one or more filter layers by a portion of the flowing gas due to inadequate support of one or more of the layers when intermediate support members are not used or are ineffective.
Still another disadvantage lies in the fact that the prior art filters tend to have high heat capacity, necessitating the use of large amounts of combustible material to effect inflation of the confinement.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved filter assembly for vehicle occupant restraint systems employing combustible gas generators which minimizes the concentration of contaminants passing through the filter.
It is another object to provide a filter which minimizes the tendency of combustion aases to bypass the ,~
J`~J
la~ 3~
filter.
It is yet another object to provide a filter whose heat capacity tends to permit the use of a minimum amount of combustion material fox effecting inflation.
According to the present invention there is provided a filter for filtration of contaminants produced in the gas flow of a gas generator of the type used for inflation in vehicle occupant restraint systems. The filter includes a plurality of layers of a first filter material, the first filter material being fibrous and porous, each of the layers of the first filter material defining a plenum zone for dispersing and filtering con-taminants contained in the gas flow throughout the plenum zone. The filter further includes a plurality of layers of second filter material, the second filter material being fibrous and having a porosity substantially less than the first filter material, the plurality of first and second filter material layers being disposed in alternating arrangement such that each layer of the second filter material is bounded on either side thereof by a layer of the first filtex material.
The above objects and features, as well as others, will be apparent to those skilled in the art of filters for occupant restraint systems employing combustible gas generators upon reading the accompanying detailed description with reference to the drawlngs in which:
i3#
Figure 1 is a fragmentary cross sectional view of a fluid supply incorporating the invention filter;
Figure 2 is an exploded fragmentary cross sectional view of the filter assembly of the present invention; and Figure 3 is a cross sectional view of the invention filter assembly taken along line 3-3 of Figure 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
. ~
Referring now to Figure 1, a fluid supply 10 is illustrated as including a cylindrical housing assembly 12, an igniter assembly 14, means 16 for generating gas for inflation through combustion, and a filter assembly 18 dis-posed between the gas generating means 16 and the housing 12.
It should be understood, however, that the illustration of the filter assembly 18 as employed in the cylindrically housed fluid supply of the drawings is not intended to be limiting.
The applicability of the invention filter to other fluid supplied (See, e.g.-, the flat pack fluid supply disclosed by applicat-~on U.S. Patent No. 4,017,100, issued April 12, 1977 and assigned to the assignee of the present invention.) will be apparent as the description continues.
The housing assembly 12 includes a base portion 20, a fluid directing portion 22, and an end cap 24. Base portion 20 is preferably secured to one end of the fluid directing portion 22 by welding or the like as illustrated at 26 and carries one end of the igniter assembly 14 in a centrally --located bore 28 closed by a plug 30.
; Fluid directing portion 22 defines a generally cylindrical shell through which a multiplicity o axially and circumferentially spaced ports 32 are formed.
The end of fluid directing portion 22 opposite ..
~ -3-, the base portion 20 is illustrated as being internally threaded at 36 to receive the end cap 24 which is externally threaded.
The igniter assembly 14 is threadedly received in a centrally located internally threaded bore 38 in the end cap 24, The igniter assembly 14 may be of any known design but is illustrated in Figure 1 as being of the type including electrical leads 140 for receiving a signal from a crash sensor (not shown) upon the occurrence of a collision.
The gas generating means 16 comprises suitable combustible material filling the space between the igniter assembly 14 and the filter assembly 18. While other com-bustible materials may be chosen, that having a granular solid form and composition as disclosed by applicant in Canadian Patent ~pplication Serial No. 240,246, filed November 24, 1975 and assigned to the assignee of the present invention is preferred. The particular arrangement of the gas generating material is preferably as set forth in the above referenced concurrent application of Applicant G. W.
Goetz.
The filter assembly 18 is formed in a substantially cylindrical configuration as may best be seen in the Figures 1 and 3 and is illustrated as including a relatively thin perforated plate 40 having formed through it a plurality of axially and radially spaced holes 42, an inner support screen 44, first and second outer support screens 46 and 48, respectively, and a plurality of layers of deformable - fibrous filter material 50.
. The components of the filter assembly 18 are arranged generally in the order of their decreasing porosity .
: ~ -4-., .
in the flow direction as taught in the U.S. Patent No.
4,017,100 and assigned to the assignee of the present invention. Inner support screen 44 is adjacent the perforated plate 40 and has a relatively high porosity and National Bureau of Standards mesh number, U.S. Standard testing sieve, market grade or equivalent such as No. 24.
First outer support screen 46 is also highly porous with a National Bureau of Standards mesh number such as #24.
Second outer support screen 48 is formed from a still more porous screen fabric such as No. 8 mesh.
The layers 50 of filter material are illustrated here as being arranged to effect filtration of the products of combustion of the gas generating means 16 while preventing clogging, channelling, or pin holing. Specifically, the layers 50 of deformable fibrous filter material, whi~h are supported by the screens 44, 46 and 48, are arranged as two sets of layers. The layers 52 and 54 may be formed of fibers having diameters in the range of about 1 to about 20 microns. In the preferred~embodiment one set comprises layers 52, 54 of high temperature washed fiberglas having fiber diameters in the range of two to ten microns such as is manufactured and sold under the trade mark "Lo Con" by Carborundum Corp., P.O. Box 339, Niagra Falls, New York 14302.
It will be clear to those skilled in the art, however, that other fibrous filter materials including those employing metallic fibers, could be used providing the layers are arranged to effect generally finer filtration in the downstream flow direction.
The other set comprises layers 51, 53, 55 of steel ~ --5--l~U~i3~
wool, preferably but not necessarily no. 0000 steel wool, which is substantially more porous than the washed fiberglas.
The layers 51, 53 and 55 may consist of fibers having diameters in the range of about 50 to about 150 microns.
As can best be seen in Fig. 2, the steel wool layers 51, 53, 55 are interdigitated with respect to the fiberglas layers 52,~54, with layer 51 being placed adjacent the inner support screen 44 and layer 55 being placed adjacent first outer support screen 46.
It is this arrangement of the layers that the present invention departs from the teaching of previously - referenced U.S. Patent No. 4,017,100. The layer arrangement described presents a filter assembly of alternating porosity to the gas flowing from the gas generating means 16 outward through the fluid directing portion 22. The steel wool layers 51, 53, 55 serve as,intermediate plenums, provide - additional support for the adjacent filter layers, and redistribute contaminants. The redistribution tends to elminate "pinholding". The additional support tends to --prevent channelling; and the provision of intermediate plenum space tends to reduce the overall heat capacity of the filter through increased filter efficiency which is defined as ~log particulates passed~heat capacity). This last effect in the preferred embodiment creates a warmer gas flow and - consequently a greater volume flow per mass of propellant, allowing use of less propellant material for inflation.
It should be clear, however, that improved filter efficiency might also be utilized to remove more solid product.s of combustion with a lower resulting gas temperature.
Many modifications of the array of filter layers ., ,. ~
3~
are possible without departing from the spirit of invention.
For example, more layers of filter and plenum material may be used, more than one plenum layer may be positioned adjacent the inner support screen 44 or different filter or plenum materials may be utilized. One specific substitution that has been successfully made is a layer of approximately 1.5 micron fiber high filtration paper such as is sold by Carborundum Corporation under the Registered Trade Mark HI-FI 660-FH PAPER.
FABRICATION AND INSTALLATION OF THE FILTER ASSEMBLY
To form the filter assembly 18 in the embodiment illustrated, the support screens 44, 46, and 48, and the layers 50 of deformable fibrous filter material are first fabricated substantially rectangular sheets of equal length denoted by reference letter -L- in Figure 2 and having widths increasing proportionally with their distance from the central axis of the housing assembly 12, as viewed in Figure 1.
The sheet forming second outer support screen 48 includes an inwardly extending flange portion 58 at one end to facilitate insertion into the housing assembly 12.
w~ --'I'he she~t forming the first outer support screen 46 includcs inwardly extending flange portions 60 on each longitudinal edge to effect closure of the filter assembly.
' After fabrication the sheets are arranged in a rlat 5l pack shown in Figure 2 and placed in a press wherein a high compressive force is applied.
Referring now to Figure 3, the resulting compressed I rectangular filter pack is subsequently formed by rolling or I like process into a resilient cylinder having a transverse 10' dimension, in its radially compressed condition, less than .he mer diameter 68 of the housing assembly 12. The barrier effect of the flange portions 60 tosether with the main-~! taining of a uniform thickness in the fabrication of the ¦, filter back insures uniform distribution of the compressed 15~I filter material.
'I ~ The perforated plate 40, which may be fabricatedfirst as a rectangular sheet, is rolled or otherwise processed to form a cylinder (as may best be seen in Figure 4) whose - , longitudinal seam 64 is closed by fixïng a thin plate 66 to the inner diameter 70 of the perforated plate 40 at the seam 64 by weldments 72 or the like and whose inner diameter 70 is sized to receive th~ gas generating means 16.
- To prepare the filter assembly 18 for installatior. in ~ !, the typical radial flow generator housing 12 the perforated ,1 25ll plate 40 is first placed within the resilient cylinder 61.
The cylinder 61 is then radially loaded by means of a fixture (not snown) which is configured to allow sliding . . ~
-8- , ;h movemcllt of the cylinder 61 with respect thereto. The longitudinal axis of cylinder 61 is then aligned with the ~ longitudinal aY.is of the housing 12. An axial load is then ; ~ applied to the filter assembly 18 to slide it out of the 5,~ fixture into the housing 12, with inwardly extending flange portion 58 of second outer screen 48 providing a relatively , smooth leading edge to facilitate insertion. In order to ~~ further aid insertion, the housing 12 may be vibrated to ,' effectively reduce the frictional forces acting between the 10; filter assembly 18 and the inner surface of housing 12.
i When installed as described in Figure 1 the filter '" assembly 18 effects filtration of the products of combustion il of the gas generating means 16 which are released to flow ,' outward through fluid directing passages 32 in the housing 12 5;¦ when the gas generating means 16 is actuated by the igniter assembly 14 upon the occurrence of a collision. Gaseous products flow outward from the gas generating means 16 through holes 42 in the perforated plate 40, bypassing being prevented 1, by the plate 66. Filtration of the solid products of the combustion is effected during passage through the screen 44, and the layers of filter material 50. Bypassing of these " portions of the filter assembly 18 is prevented through the ',j positioning of the seam 62.
, Although the filter assembly of the present invention has 25~ been described in only certain embodiments, o.her embodiments and modifications may be constructed without departing from the spirit of the invention as presently claimed.
.
,~
Claims (8)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A filter for filtration of contaminants produced in the gas flow of a gas generator of the type used for inflation in vehicle occupant restraint systems, said filter comprising:
(a) a plurality of layers of a first filter material, said first filter material being fibrous and porous, each of said layers of first filter material defining a plenum zone for dispersing and filtering contaminants contained in said gas flow throughout said plenum zone; and (b) a plurality of layers of a second filter material, said second filter material being fibrous and having a porosity substantially less than said first filter material, said plurality of first and second filter material layers being disposed in alternating arrangement such that each layer of said second filter material is bounded on either side thereof by a layer of said first filter material.
(a) a plurality of layers of a first filter material, said first filter material being fibrous and porous, each of said layers of first filter material defining a plenum zone for dispersing and filtering contaminants contained in said gas flow throughout said plenum zone; and (b) a plurality of layers of a second filter material, said second filter material being fibrous and having a porosity substantially less than said first filter material, said plurality of first and second filter material layers being disposed in alternating arrangement such that each layer of said second filter material is bounded on either side thereof by a layer of said first filter material.
2. The filter as defined in claim 1, wherein:
(a) said first material comprises fibers having diameters in the range of about 50 to about 150 microns;
and (b) said second filter material comprises fibres having diameters in the range of about 1 to about 20 microns.
(a) said first material comprises fibers having diameters in the range of about 50 to about 150 microns;
and (b) said second filter material comprises fibres having diameters in the range of about 1 to about 20 microns.
3. The filter as defined in claim 1 wherein said second filter material comprises fiberglass and said first material comprises steel wool.
4. The filter as defined in claim 1 wherein each layer of said first material is of substantially equal porosity.
5. The filter as defined in claim 1 wherein each layer of said second filter material is of sub-stantially equal porosity.
6. The filter as defined in claim 1, wherein:
(a) said first filter material is metallic; and (b) said second filter material is nonmetallic, said plurality of layers of said second filter material are arranged to effect progressively finer filtration of contaminants in a downstream direction.
(a) said first filter material is metallic; and (b) said second filter material is nonmetallic, said plurality of layers of said second filter material are arranged to effect progressively finer filtration of contaminants in a downstream direction.
7. The filter as defined in claim 1, wherein:
(a) said first filter material is metallic; and (b) said second filter material is metallic, said plurality of layers of said second filter material is arranged to effect progressively finer filtration of contaminants in a downstream direction.
(a) said first filter material is metallic; and (b) said second filter material is metallic, said plurality of layers of said second filter material is arranged to effect progressively finer filtration of contaminants in a downstream direction.
8. The filter as defined in claim 1, wherein each of said second filter material layers is progressively less porous in the direction of flow.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US65813176A | 1976-02-13 | 1976-02-13 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1080638A true CA1080638A (en) | 1980-07-01 |
Family
ID=24640020
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA270,328A Expired CA1080638A (en) | 1976-02-13 | 1977-01-24 | Filters for vehicle occupant restraint system fluid supplies |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS6055331B2 (en) |
| CA (1) | CA1080638A (en) |
| DE (1) | DE2705942A1 (en) |
| FR (1) | FR2340762A1 (en) |
| GB (1) | GB1554070A (en) |
| IT (1) | IT1077613B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2021220114A1 (en) * | 2020-04-30 | 2021-11-04 | N2 Global, Sia | A fire suppressing gas generating device comprising an improved filtering and heat absorbing filter |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS54155536A (en) * | 1978-05-29 | 1979-12-07 | Nippon Oil & Fats Co Ltd | Gas generator |
| JP2598816B2 (en) * | 1988-12-05 | 1997-04-09 | 日本工機株式会社 | Gas filter for airbag deployment gas generator |
| DE3911826A1 (en) * | 1989-04-11 | 1990-10-31 | Seitz Filter Werke | FILTER CANDLE OR FILTER MODULE MADE OF FLEXIBLE DEPTH FILTER MATERIAL |
| US5269921A (en) * | 1989-04-11 | 1993-12-14 | Seitz-Filter-Werke Gmbh & Co. | Filter cartridge or filter module consisting of flexible deep filter material |
| DE4005768A1 (en) * | 1990-02-23 | 1991-08-29 | Bayern Chemie Gmbh Flugchemie | Cylindrical gas generator for vehicle airbag - incorporates two chambers enclosed by filter |
| DE69502344T2 (en) * | 1994-05-17 | 1998-11-19 | Isuzu Ceramics Res Inst | Diesel particulate filter |
| TW527294B (en) * | 1999-11-29 | 2003-04-11 | Daicel Chem | Gas generator for air bag and devices for the same |
| DE102004001417A1 (en) * | 2004-01-09 | 2005-08-04 | Emitec Gesellschaft Für Emissionstechnologie Mbh | Particle filter comprising a metallic fiber layer |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL86719C (en) * | 1951-12-17 | |||
| GB1238843A (en) * | 1967-07-15 | 1971-07-14 | ||
| FR2070980A5 (en) * | 1969-12-12 | 1971-09-17 | Bruder Michel | Air or liquid filter - with cartridge formed from two layers - of different mesh size |
| US3904221A (en) * | 1972-05-19 | 1975-09-09 | Asahi Chemical Ind | Gas generating system for the inflation of a protective bag |
| US3877882A (en) * | 1972-07-27 | 1975-04-15 | Talley Industries | Gas generating device |
| JPS4988770A (en) * | 1972-12-26 | 1974-08-24 | ||
| US3880447A (en) * | 1973-05-16 | 1975-04-29 | Rocket Research Corp | Crash restraint inflator for steering wheel assembly |
| US4017100A (en) * | 1975-01-08 | 1977-04-12 | Eaton Corporation | Fluid supply, filter pack used therein and method of assembly |
| US4012211A (en) * | 1975-06-30 | 1977-03-15 | Eaton Corporation | Filter for occupant restraint system fluid supply |
-
1977
- 1977-01-24 CA CA270,328A patent/CA1080638A/en not_active Expired
- 1977-01-28 GB GB362177A patent/GB1554070A/en not_active Expired
- 1977-02-07 IT IT2002677A patent/IT1077613B/en active
- 1977-02-11 FR FR7703915A patent/FR2340762A1/en active Granted
- 1977-02-12 DE DE19772705942 patent/DE2705942A1/en active Granted
- 1977-02-14 JP JP52014327A patent/JPS6055331B2/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2021220114A1 (en) * | 2020-04-30 | 2021-11-04 | N2 Global, Sia | A fire suppressing gas generating device comprising an improved filtering and heat absorbing filter |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2340762A1 (en) | 1977-09-09 |
| FR2340762B1 (en) | 1983-05-13 |
| JPS52129126A (en) | 1977-10-29 |
| DE2705942C2 (en) | 1989-12-28 |
| GB1554070A (en) | 1979-10-17 |
| DE2705942A1 (en) | 1977-08-18 |
| JPS6055331B2 (en) | 1985-12-04 |
| IT1077613B (en) | 1985-05-04 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry | ||
| MKEX | Expiry |
Effective date: 19970702 |