Filter bag sewn SEAM seal

Abstract

A fibrous layer is used to reduce emissions at a sewn seam in a filter such as a filter bag. This filter includes a filter media, which include a substrate media laminated to filtration layer. A fibrous layer of free fibers is provided such as by a seam tape overlayed upon the overlapping edge portions of the filter media to be seamed. During stitching with a thread, the needle and thread driven thereby pulls free fibers from the fibrous layer of the seam tape into needle openings as the seam tape is stitched to the filter media. This effectively seals the needle openings that are created with the free fibers at least partially plugging at this location.

Description

FILTER BAG SEWN SEAM SEALCROSS-REFERENCE TO RELATED PATENT APPLICATIONS

[0001] This PCT Patent Application claims the benefit of U.S. Provisional Patent Application No. 63 / 692,236, filed September 9, 2024 and U.S. Provisional Patent Application No. 63 / 655,673, filed June 4, 2024, the entire teachings and disclosure each of which are incorporated herein by reference thereto.FIELD OF THE INVENTION

[0002] This invention generally relates to seams in filter medias, such as in bag filters for example, and more particularly to sewn seams in filter medias and filters.BACKGROUND OF THE INVENTION

[0003] When certain bag-type filtration products are created they have to be seamed. The seam can be accomplished by sewing the material, for example, seams are shown in referenced patents US8790432B2 and US20080044614.

[0004] Sewn seams on filter bags, particularly woven fiberglass bags can be a significant source of emissions. Alternative technologies such as sonic-welded seams does not apply to fiberglass. In addition, sewing can separate or damage the yams in laminated woven fiberglass which causes emissions problems for customers. Some have sewn PTFE tape into the tube seams of their filtration products in an attempt to eliminate this issue. While others have placed a bonding liquid into the seams.

[0005] Testing reveals that sewing PTFE tape into the seam doesn't adequately seal the seam and can contribute to higher emissions.BRIEF SUMMARY OF THE INVENTION

[0006] The present application relates to new seam seal design that can be applied to different filter applications, such as for example, any woven fiberglass filter bag typically used in cement, metals, and carbon black production.

[0007] An inventive aspect is directed toward a filter comprising a filter media comprising a support layer and a filtration layer attached thereto by a lamination therebetween, with the filter media comprising a first edge portion and a second edge portion arranged adjacent in an overlapping relation. Further, a layer of fibers are provided at the overlapping relation between the first edge portion and the second edge portion. A thread is stitched through each of the first edge portion and the second edge portion, and with some of the fibers projecting into the filter media to reside between the thread and the filter media.

[0008] According to another inventive aspect, a filter comprises a filter media comprising a first edge portion and a second edge portion arranged adj acent in overlapping relation. The filter further comprises a seam tape providing at least one fibrous seam layer comprising a layer of fibers, with the seam tape overlapping the first edge portion and the second edge portion. A thread stitched through each of the first edge portion, the second edge portion, and the seam tape, wherein some of the fibers from the seam tape reside between the thread and the filter media.

[0009] Different features and embodiments below may be employed with the either or both of the above inventive aspects either alone or in combination.

[0010] It is a feature that the filter further comprises a seam tape providing at least one fibrous seam layer comprising the layer of fibers. The seam tape can overlap the first edge portion and the second edge portion.

[0011] In the above seam tape feature, the seam tape can be provided by a strip of fabric that is folded into overlapping relation upon itself.

[0012] In the above seam tape feature, the seam tape / strip is folded to provide at least three fibrous seam layers overlapping upon the first edge portion and the second edge portion.

[0013] In the above seam tape feature, the seam tape / strip is a texturized fabric having a texturized side with a greater amount of texturized yams exposed on one side of the texturized fabric. Preferably, the folds of the strip are arranged such the texturized side along at least two of the fibrous seam layers are positioned facing the filter media, and the texturized side along one of the fibrous seam layers is in contact with the filter media.

[0014] In the above seam tape feature, the seam tape comprises at least one woven or non-woven media selected from the following group of: a fiberglass, a polyester, a polypropylene, a fluoropolymer, an acrylic, an aramid, a polyphenylene sulfide (PPS), and / or a polyimide.

[0015] In the above seam tape feature, some of the fibers of the fibrous seam tape are mechanically pulled through both of the first edge portion and the second edge portion. For example, this is accomplished in an embodiment via a stitching needle.

[0016] It is a feature that the layer of fibers may alternatively be provided by loose fibers of a non-fabric material.

[0017] In the above feature, the loose fibers can be applied in a localized region over the filter media.

[0018] It is a feature that the layer of fibers may alternatively be provided by a localized region of loose fibers mobilized off of the support layer, the loose fibers being looser in the localized region than a remainer of the support layer.

[0019] It is feature for the filter that the overlapping relation may create a felled seam, a lapped seam, an overlap seam, a butt seam, or a hem.

[0020] It is a feature that the fibers (e.g.. layer of fibers) are provided by an overlay media having variable fiber mobility, with a higher fiber mobility on one side as compared to the other side.

[0021] It is a feature that the layer of fibers are provided by a texturized fabric having a texturized side with a greater amount of texturized yams exposed on one side of the texturized fabric. Preferably, at least a portion of the texturized side of the fabric is positioned facing and in contact with the filter media.

[0022] It is a feature that the support layer comprises at least one woven or non-woven media selected from the following group of: a fiberglass, a polyester, a polypropylene, a fluoropolymer, an acrylic, an aramid, a polyphenylene sulfide (PPS), and / or a polyimide.

[0023] It is a feature that the filtration layer comprises at least one media selected from the following group of: an expanded fluoropolymer membrane, and a fine fiber polymer entanglement of polymeric fibers having an average fiber size of less than 5 micron and preferably less than 1 micron.

[0024] It is a feature that the support layer comprises: a thickness of between 0 and 3 millimeters, more preferably between 0.2 and 1.5 millimeters, and a basis weight of up to 1700 grams / square meter, and more preferably between 300 and 850 grams / square meter; and wherein the filtration layer comprises: a thickness of between 1 and 72 micron, more preferably between 4 and 30 micron, and a basis weight of between 0.2 and 8.4 grams / square meter, and more preferably between 1 and 7 grams / square meter.

[0025] It is a feature according to a more specific embodiment that the support layer comprises a woven fiberglass substrate, wherein the filtration layer comprises an expanded fluoropolymer membrane, and wherein the fibers are provided by texturized fiberglass yams.

[0026] In the above feature, the texturized fiberglass yams are provided by a fiberglass fabric layer that is preferably woven, the texturized fiberglass yams separately provided from the first edge portion and a second edge portion.

[0027] It is a feature that at least two rows of the thread are stitched through each of the first edge portion and the second edge portion.

[0028] It is a feature that at least some fibers (e.g., from the layer of fibers) project entirely through first edge portion and the second edge portion and exposed to opposite sides of the filter media and plug holes around the thread.

[0029] It is a feature that a seam between the first edge portion and the second edge portion are sealant-free and adhesive-free.

[0030] It is a feature that the filter media has an efficiency of at least MERV 8, and more preferably at least MERV 14, as defined by ASHRAE 52.2-2017.

[0031] It is a feature that the filter is configured as a bag filter in with the filter media configured into a sleeve having an open end and a closed end.

[0032] Another inventive aspect is directed toward a method of making a filter, comprising: overlapping a first edge portion and a second edge portion of a filter media; providing a supply of available fibers at the first and second edge portions; stitching a thread through each of the first edge portion, the second edge portion, and the available fibers; and pulling at least some fibers from the available fibers during the stitching into the filter media to seal between the thread and the filter media.

[0033] Different features and embodiments below (or such features / embodiments above) may be employed with the either or both of the above inventive aspects either alone or in combination.

[0034] It is a feature that the method may further comprise laminating a support layer and a filtration layer together to provide the filter media.

[0035] It is a feature that the providing such supply of available fibers may comprise overlapping a seam tape upon the first edge portion and the second edge portion, with the seam tape comprising a layer of fibers providing the available fibers.

[0036] The above seam tape feature may further comprise folding the seam tape upon itself to provide multiple layers of the fibers overlapping the first edge portion and the second edge portion.

[0037] In the above seam tape feature, the seam may be provided by a texturized fabric having a texturized side with a greater amount of texturized yams exposed on one side of the texturized fabric; and the method may further comprise arranging at least a portion of the texturized side of the fabric to be facing and in contact with the filter media for stitching.

[0038] It is a feature that the supply of available fibers (for example, a seam tape) may comprise at least one woven or non-woven media selected from the following group of: a fiberglass, a polyester, a polypropylene, a fluoropolymer, an acrylic, an aramid, a polyphenylene sulfide (PPS), and / or a polyimide; and / or the support layer may comprise at least one woven or non-woven media selected from the following group of: a fiberglass, a polyester, a fluoropolymer, an acrylic, an aramid, a polyphenylene sulfide (PPS), and / or a polyimide; and / or the filtration layer may comprise at least one media selected from the following group of: an expanded fluoropolymer membrane, and a fine fiber polymer entanglement of polymeric fibers having an average fiber size of less than 5 micron and preferably less than 1 micron.

[0039] It is a feature that the method may comprise locally mobilizing fibers from the filter media proximate at least one of the first edge portion and the second edge portion to generate a supply of available fibers. For example, one or both edge portions may be roughened prior to stitching and / or overlapping.

[0040] It is a feature that the method may comprise providing available fibers by applying loose fibers separate of any fabric over the filter media prior to stitching.

[0041] It is a feature that the method may comprise configuring the filter media into a filter bag with the stitching.

[0042] According to a particular preferred embodiment, the seam seal design adds a 3- ply layer of woven fiberglass over a felled-seam. The 3-ply layer of fiberglass provides that the fiberglass filaments to be mobile so that when sewn into seam, fibers from the seal layer are mechanically pulled into the hole created when the sewing needle and thread penetrate the fabric filter body. This movement of fiberglass filaments into the seam create a durable seal, by effectively plug larger openings and making a tortuous path for fluid to pass along the seam. Although such durable seal provided and disclosed herein may not be a hermetic seal, testing shows that the 3-ply woven fiberglass seam seal can enable the sewn seam to have emissions equal to or less than the laminated filter fabric (i.e., the sewn seam does not contribute to higher emissions). While such particular embodiment employs a seal that is of woven material and a seam that is of w oven material, such seal could be made with woven or non-woven media; and likewise, the material of seam that the seal is sealing may be made with woven or non-woven media.

[0043] For example, the specially folded three-ply "sleeve covering" section of media is sewn onto the felled tube seam. The "sleeve covering" is sewn onto the outer surface of the tube seam on the filtration product. Alternatively, for example, loose fibers can be used to seal the sewing. For example, loose fibers not yet in a fabric (and separate from the filter media used in the filter bag) can be applied to the filter media before sewing. Another option is to mobilize the fibers of the base filter media where it is to be sewn to provide a local region of loose fibers. Loosening fibers in a localized region of the seam area may have the effect of sealing without the addition of loose fibers or a sleeve that supplies loose fibers.

[0044] For example, in an embodiment, the 3-ply sleeve covering is made from a 3X1 twill fiberglass fabric which has a greater proportion of texturized yams exposed on one side of the fabric. The texturized side of the fabric is positioned to the outside of the sleeve covering. This orientation of the texturized yams causes them to mate with the filter bag body. The texturized yams on the outer layer are designed to have no significant bonding or restriction of movement (such as in ePTFE lamination). The freedom of movement for yam filaments in the sleeve covering causes them to interlock into the tube seam when needle and thread penetrate through the layers. The texturized yam filaments from the sleeve covering fill in holes or damage to the filter bag caused by the needle and thread.

[0045] Other fabric styles which allow for movement of fibers or filaments such as a needlefelt could be used in place of the 3X1 twill as long as the fiber movement is sufficient to seal the seam. Specific examples of fabric with potential utilization in this design are Acrylic, Fiberglass. Aramid (e.g., Nomex), polyphenylene sulfide (PPS), Polyester, a polyimide (e.g., P84), polypropylene, and a fluoropolymer (e.g. PTFE such as ePTFE).

[0046] In an example, the sleeve cover is a 2.25-inch strip of fabric when unfolded, and when folded into its completed form becomes a 3 layer "sleeve" with a final width of 0.75 inches. This can be a standard size of this new sleeve component. Its size isn't dependent on the seam it is being sewn over. The center axis of the new "sleeve" will be lined up with the center axis of the filter bodies "tube seam". While a 2.25-inch strip of fabric may be preferred, other examples of the sleeve cover may have a strip width of between 0.25 inch and 12 inches, and more preferably between 0.5 inch and inches; and such 3 layer (or other single or multilayer) "sleeve" can a final width of between 0.25 inch and 6 inches, and more preferably between 0.5 inch and 2 inches.

[0047] According to one embodiment, a filter is provided, comprising: (a) woven fiberglass filter media including two adjacent edge portions in overlapping relation; and (b) a multilayered fiberglass seam tape layered lengthwise along the adjacent edge portions and needle stitched with the overlapping edge portions to define a seam, wherein fibers of the seam tape are forced into needle openings as the seam tape is stitched to the filter media.

[0048] The seam tape is preferably a folded strip of three adjacent lengthwise-extending layers.

[0049] According to a further aspect, a method is provided for forming a seam along a woven fiberglass filter bag. comprising the steps of: (a) bringing edge portions of the filter bag into adjacent, overlapping relation; (b) layering a multilayered fiberglass seam tape lengthwise along the overlapping edge portions of the filter bag; and (c) stitching through the seam tape and through the overlapping edge portions with a needle to form a seam.

[0050] The method can further include the step of folding the strip of seam tape into three adjacent lengthwise extending layers prior to layering the seam tape along theoverlapping edge portions of the filter bag, the needle forcing fibers of the seam tape into openings in the overlapping edge portions created by the needle during stitching to form the seam.

[0051] According to another embodiment, a filter is provided, comprising: (a) woven fibrous filter media including two adjacent edge portions in overlapping relation; and (b) a multilayered fibrous seam tape layered lengthwise along the adjacent edge portions; and (c) the seam tape needle-stitched to the overlapping edge portions with fibers of the seam tape forced into openings in the overlapping edge portions created by the needle during stitching to form a seam.

[0052] The seam tape can be a folded strip of three adjacent lengthwise-extending fibrous layers, and the seam is preferably adhesive-free.

[0053] Other aspects, objectives and advantages of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention and, together with the description, serve to explain the principles of the invention. In the drawings:

[0055] FIG. 1 is a partly schematic, cross-sectional view of an embodiment of a bag house that may employ a filter bag according to an embodiment of the present invention. ;

[0056] FIG. 2 is a perspective view of a filter bag according to an embodiment of the present invention that may be employed into the tube-sheet baghouse application of FIG. 1 ;

[0057] FIG. 3 is a cross-section through the seam of the filter bag show n in FIG. 2; and

[0058] FIG. 4 is a photograph of an external view of the tube seam of a filter bag that has been partially cut away, according to an embodiment of the present invention (e g. as in the filter bag FIG. 2);

[0059] FIG. 5 is a photograph of the opposite internal view (e.g., showing the innermost layer as a filter membrane layer) of the tube seam of the filter bag shown in FIG. 4;

[0060] FIGS. 6-9 are microscopic images of the stitching along the membrane side of the filter media that is on the opposite of the seam tape of the tube seam, in which it can be seen such as in blue free fibers that are also identified by reference numbers that have been fully pulled through the filter media to the side opposite of the seam tape to plug the holes from thread stitching;

[0061] FIG. 10 is a photograph of texturized yams and non-texturized yams that can be employed into the seam tape of the tube seam in the embodiments shown in other figures;

[0062] FIG. 11 is a schematic cross-section view through the tube seam showing the stacking of layers of material that are stitched for the embodiments shown in the various figures;

[0063] FIG. 12 is a schematic cross-section view through the folded sleave (seam tape) component for the stacked layers of FIG. 11;

[0064] FIG. 13 is the sleeve material shown in FIG. 12 but prior to folding into multiple layers;

[0065] FIG. 14 is an isometric view of the filter bag shown in earlier figures with a cross section taken through the tube seam and seam tape, and schematically showing the free fibers being higher along one side face of the seam tape and schematically showing free fibers being pulled through the filter media from the seam tape (which are shown in photographs in FIGS. 6-9).

[0066] While the invention will be described in connection with certain preferred embodiments, there is no intent to limit it to those embodiments. On the contrary, the intentis to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention as defined by the appended claims.DETAILED DESCRIPTION OF THE INVENTION

[0067] As shown in FIG. 2, an embodiment of the present invention has been illustrated filter, for example that may take the form of a filter bag 10, with a sew n seam 12 having additional fibrous overlay that are sewn therein to provide for improved sealing at the seam 12.

[0068] Filter Bag Working Environment

[0069] Before turning details of the seal in sewn seam 12, an understanding of a example working environment is provided. The filter bag 10 may be employed in a baghouse as shown in FIG. 1. The bag house 20 may include three sections: an air inlet section 22, an air cleaning section 24, and an air outlet section 26. The air inlet section 22 includes a dirty gas inlet 28; baffles 30, 32, 34, and 36; and a hopper 38. The air cleaning section 24 includes, filter bags 40, 42, 44, and 46 (any of which can be provided by one or more of the filter bags 10 of FIG. 2); tube sheet 48; cage covers 50, 52, 54, and 56; and cages 58 within the filter bags 40, 42, 44, and 46. The air outlet section 26 includes blowpipe 60, compressed air header 62, and clean air outlet 64.

[0070] The bag house 20 allows dirty air 66 (e.g. air filled with particulates or debris) to enter the air inlet section 22 through the dirty gas inlet 28. The dirty' air 66 after passing through the dirty gas inlet 28 contacts the baffles 30, 32. 34, and 36. The baffles 30, 32, 34, and 36 direct the dirty air in a direction towards the clean air outlet 64. As the dirty air 66 moves in the direction of the clean air outlet 64, it contacts the filter bags 40, 42, 44, and 46 (e.g., fabric filter bags such as can be provided by filter bag 10).The filter bags 40, 42, 44, and 46 allow' air to pass through the bags 40, 42, 44, and 46, while blocking the passage of undesirable particulates. Accordingly, as the dirty’ air 66 passes through the filter bags 40, 42, 44, and 46, particulates are left on the outside of the bags 40, 42, 44, and 46. The clean air 68 within the filter bags 40, 42, 44, and 46 thencontinues to progress through the filter bags 40, 42, 44, and 46 until reaching the outlet section 26, where the clean air is able to exit through the clean air outlet 64.

[0071] The filter bags 40, 42, 44, and 46 attach to the air cleaning section 24 with a respective adjustable band. The adjustable bands fit within apertures of the tube sheet 48. While in the present embodiment, the tube sheet 48 includes four apertures one for each filter bag 40, 42, 44, and 46, it is understood that the tube sheet 48 may include more apertures for example ten to one-hundred apertures. The filter bags 40, 42, 44, and 46 maintain their shape under the force of the dirty7air 66, because of cages 58 placed into the filter bags 40, 42, 44, and 46 (or pleated filter elements may be placed therein in which the bag is a first stage of filtration).

[0072] The cages 58 may be made out of materials, such as steel or other metals, hard plastics, etc. that are able to resist deformation under the air pressure of the bag house 20. The cages 58 maintain the shape of the filter bags 40, 42, 44, and 46 under pressure from the dirty- air 66 allowing the filter bags 40, 42, 44, and 46 to increase air filtration. The cages 58 attach to the cage covers 50, 52, 54, and 56. The cage covers 50. 52. 54. and 56 stabilize the filter bags during operation and facilitate insertion and removal of the cage 58 into and from the filter bags, facilitating the filter bag replacement process.

[0073] The filter bags 40, 42, 44. and 46 during use become covered in filtered particulate reducing the filtration ability of the filter bags 40, 42, 44, and 46. This problem is solved by periodically pulse jetting air into the filter bags 40, 42, 44, and 46 to knock particulate off the filter bags 40, 42, 44, and 46. As mentioned above, the outlet section 26 includes a blowpipe 60 and a compressed air header 62. The compressed air header 62 during pulse jet operations pulses compressed air into blowpipe 60. The blowpipe 60 then directs the pulsed compressed air through openings 70, 72, 74, and 76 into the filter bags 40, 42, 44, and 46. The pulses of compressed air shake the filter bags 40, 42, 44, and 46 sufficiently to knock particulate loose. The loose particulate may then drop into the hopper 38 of the air inlet section 22, where it may be removed from the bag house 20.

[0074] The blowpipe 60 can pulse air into a filter bag 10 (e.g. filter bags 40, 42, 44, and 46). As discussed above, the air outlet section 26 includes a blowpipe 60 that blowscompressed air into the filter bags 40, 42, 44, and 46. The pulsed air from the compressed air header 62 travels through the blowpipe 60 and exits through the blowpipe aperture 70 in the form of air pulses 90. These air pulses enter the filter bag 10 and cause it to shake, vibrate, etc. sufficiently to knock particulate loose from the outside surface 92 of the filter bag 10.

[0075] Further Details Of Filter Bag and Sewn Seam

[0076] Returning to FIG. 2, and with additional reference to FIGS. 3-14, a filter (e.g. that may be incorporated into an embodiment as the filter bag 10 as shown) comprises a filter media 100. For example, the filter may configured as a tubular bag filter as shown in FIG. 2, which is configured a sleeve 14 having an open end 16 and a closed end 18.

[0077] The filter media 100 can comprise a support layer 102 and a filtration layer 104 attached thereto by a lamination 106 therebetween (e.g., thermally coupled, mechanically coupled, glued, welded and / or otherwise integrally bonded together). The filter media 100 comprises a first edge portion 108 and a second edge portion 110 arranged adjacent in an overlapping relation, as shown best in FIGS. 3, 11 and 14.

[0078] Additionally, a layer 11 1 of fibers 112 are provided at the overlapping relation of the first edge portion 108 and the second edge portion 110.

[0079] A thread 114 (for example at least one thread 114, and preferably more than one such three of such threads 114 in this embodiment) has been stitched through each of the first edge portion 108 and the second edge portion 110, thereby fastening the edge portions 108, 110 together. Some of the fibers 112 project into the filter media 100 to reside between the thread 114 and the filter media 100.

[0080] The fibers 112 of the fiber layer 111 are not subject to being trappings of the lamination 106 as between the support layer 102 and the filtration layer 104 and therefore have mobility and are free of the lamination constraint. As a result, during sewing operation, such free fibers 112 can be displaced during sewing to stuff and plug / seal betw een the thread 114 and the filter media 100. As shown, some of the fibers 112 fromfiber layer 111 are thereby displaced therefore due to the free mobility of such fibers 112 during sewing.

[0081] For example, this can be seen by the displaced free fibers 113 that are shown in the photos of FIGS. 6-9 and schematically in FIG. 14 showing such displaced free fibers 113 having been displaced (e.g. pulled) from one side of the filter media 100 upon which the fiber layer 111 is arranged to project into the filter media, and which may reach all the way to the other side of the filter media 100 opposite the side upon which the fiber layer 111 is arranged as can be seen in the photos.

[0082] Advantageously, by residing between the thread 114 and the filter media 100, the fibers 112 can plug and seal the hole (i.e., annular region between thread and filter media) created by the thread 114 during stitching.

[0083] In the illustrated embodiment, the fibers 112 are preferably provided by a seam tape 116 providing at least one fibrous seam layer 118 providing the layer of fibers 112. The seam tape 116 is arranged overlapping the first edge portion 108 and the second edge portion 110.

[0084] As an alternative to the seam tape 116, a deposition of fibers 112 or creation of free fibers 112 to the filter media 110 can be generated at the overlapping relation of the first edge portion 108 and the second edge portion 110, which is another means to provide such fibers 112 that can plug and seal the stitching and sewn seam 112.

[0085] While other possibilities exist, the seam tape 116 provides a readily workable strip that can readily and reliably be placed upon the filter media 100 at the seaming location; and readily observed for proper sealing improvement.

[0086] Accordingly, preferably, the layer of free fibers may be a separate component part / material that is added and not an integral part of the filter media 100.

[0087] Additionally, the seam tape 116 may cover a minority portion of the overall filter bag (e.g., preferably less than 15% of the area of the filter bag), which provides costadvantages by not having to have a third layer over the entire bag. and further this does not create a new air flow restriction other than the targeted location of the sewn seam 12. The filter bag may be more breathable as a result while retaining filtering efficiency functions.

[0088] The seam tape 116 is provided by a strip 119 of fabric as shown in FIG. 13 that preferably is folded into overlapping relation upon itself as shown in FIG. 12 to increase the availability of the free fibers 112 and provide additional thickness at the sewn seam 12.

[0089] For example, the seam tape 1 1 may be a single unitary strip of fabric.

[0090] In the embodiment show n best in FIGS. 3, 11-12 and 14, the strip 119 is folded to provide at least three of fibrous seam layers 120, 121, 122 overlapping upon the first edge portion 108 and the second edge portion 110.

[0091] For example, the strip 119 can be a texturized fabric having a greater proportion of texturized yams 124 exposed on one side of the fabric strip 119 to provide a texturized side 124. This is best schematically shown in FIG. 14. As also shown in FIG. 14, the folds of the strip are arranged such the texturized side 124 along at least two of the fibrous seam layers 121, 122 are positioned facing the filter media 100, and the texturized side 126 along one of the fibrous seam layers 122 is placed in direct contact with the filter media 100.

[0092] For example, the texturized yams 124 can be made of fiberglass or other material filaments (fibers of continuous / infinite length). To create texturized yams, a yam manufacturer will first typically create smooth filaments that are wound into a yam, and texturizing (e.g. such as air jets / mechanical break / fracture / expand filaments), is conducted on yams which are positioned in the weave pattern so that a greater % of texturized yams are exposed on one side and a greater % of smooth yams are exposed on the opposite side. This texturizing breaks the filaments into shorter fibers and / or expands / displaces filaments, thereby providing for free and mobile fibers 112 that can then be used to project with the thread to fill the holes created thereby during sowing. For example, texturized yams 124 are shown in FIG. 10 that is representative of the texturized side (see free fibers 112 created thereby). However non-texturized yams 125 as shown in FIG. 10 may also be used. In particular, there are two yams featured in figure 10. The yam at the top is a texturizedfiberglass yam while the yam at the bottom is a non-texturized fiberglass yam.Embodiments herein are captured best with texturized yams 124 but can also work with the non-texturized yams 125 as well. Herein in the broader claims, all yam types are covered in that the idea is embedding yam into needle openings which works with many constructions, albeit works best with the texturized yams 124.

[0093] The side 128 opposite the texturized side 124 may have fewer texturized yams exposed. This is shown in FIG. 14, showing one side having more free fibers 112 in the seam tape 116.

[0094] In the illustrated embodiment, the texturized fiberglass yams 124 are provided by a fiberglass fabric layer 111 that is preferably woven. As a result, the layer 111 is a separate component from the filter media 100 with the texturized fiberglass yams 124 separately provided from the first and second edge portion 108, 110.

[0095] This availability' of different fiber mobility' on opposite sides of the fibrous layer 111 thereby provides overlay media having variable fiber mobility, with a higher fiber mobility on one side as compared to the other side.

[0096] In particular, the fibrous layer 111 of free fibers 112 may provided by a texturized fabric having a greater proportion of texturized yams exposed on one side of the fabric to provide a texturized side, wherein at least a portion of the texturized side 124 of the fabric is positioned facing and in contact with the filter media 100.

[0097] For example, the specially folded three-ply "sleeve covering" section of media (also referred to a fabric strip 119) is sewn onto the felled tube seam 12. The "sleeve covering" is sew n onto the outer surface of the tube seam on the filtration product.

[0098] For example, in an embodiment, the 3 -ply sleeve covering may be made from a 3X1 twill fiberglass fabric which has a greater proportion of texturized yams 124 exposed on one side of the fabric. For example, commercially available twill fiberglass fabric that are texturized include BGF Industries Style 427-A61 and 454-625 . The texturized side of the fabric is positioned to the outside of the sleeve covering. This orientation of thetexturized yams causes them to mate with the filter bag body. The texturized yams on the outer layer are designed to have no significant bonding or restriction of movement (such as in ePTFE lamination). The freedom of movement for yam filaments in the sleeve covering causes them to interlock into the tube seam when needle and thread penetrate through the layers. The texturized yam filaments from the sleeve covering fill in holes or damage to the filter bag caused by the needle and thread.

[0099] Other fabric styles which allow for movement of fibers or filaments such as a needlefelt could be used in place of the 3X1 twill as long as the fiber movement is sufficient to seal the seam. Specific examples of fabric with potential utilization in this design are Acrylic, Fiberglass, Aramid (e.g., Nomex), polyphenylene sulfide (PPS), Polyester, a polyimide (e.g., P84), polypropylene, and a fluoropolymer (e g. PTFE such as ePTFE).

[0100] As evident in some fibers 112 of the fibrous layer 111 are mechanically pulled through both of the first edge portion 108 and the second edge portion 110. This can be seen by the displaced free fibers 113 that are shown in the photos of FIGS. 6-9 and schematically in FIG. 14 showing such displaced free fibers 113 having been displaced (e.g. pulled) from one side of the filter media 100 upon which the fiber layer 111 is arranged to project into the filter media 100. Indeed, as show n in the photos of FIGS. 6-9, some fibers 112 have been displaced entirely through the first and second edge portions 108, 110.

[0101] In the illustrated, embodiment as felled type of sewn seam 12 is illustrated. This felled sewn seam 12 (also sometimes known as ‘'flat-fell seam”), is a seam made by placing one edge inside a folded edge of fabric, then stitching the fold down. The fold encases the raw edges, which protects them from fraying. The fold may be secured with a topstitch or a whipstitch. It is useful for keeping seam allowances flat and covering raw edges.

[0102] While a felled sewn seam 12 is preferred, the use of a fibrous layer 111 may also be employed when the seam 12 is a lapped seam, an overlap seam, a butt seam, or a hem.

[0103] Turning to the details of the filter media 100, the support layer 102 comprises at least one woven or non-w oven media selected from the following group of: a fiberglass, a polyester, a polypropylene, a fluoropolymer, an acrylic, an aramid, a polyphenylene sulfide(PPS), and / or a polyimide. For example, in the illustrated embodiment and photos, the support layer 102 is a woven fiberglass.

[0104] The filtration layer 102 comprises at least one media selected from the following group of: an expanded fluoropolymer membrane, and a fine fiber polymer entanglement of polymeric fibers having an average fiber size of less than 5 micron and preferably less than 1 micron. For example, the illustrated embodiment and photos, the filtration layer 104 is a expanded fluoropolymer membrane in this case provided by ePTFE.

[0105] The support layer 102 is a more open material to provide a lattice support structure, while the filtration layer 104 is of a tighter porosity having a greater filtration efficiency than the support layer 102 and functions to filter out particles.

[0106] In E pical applications, the filter media 100 has an efficiency of at least MERY 8, and more preferably at least MERV 14, as defined by ASHRAE 52.2-2017.

[0107] To provide some context, the support layer 102 typically comprises: a thickness of up to 3 millimeters, preferably between 0.2 and 1.5 millimeters, and a basis weight of up to 1700 grams / square meter, and more preferably between 300 and 850 grams / square meter; whereas the filtration layer 104 typically comprises: a thickness of between 1 and 72 micron, more preferably between 4 and 30 micron, and a basis weight of between 0.2 and 8.4 grams / square meter, and more preferably between 1 and 7 grams / square meter.

[0108] To provide a reliable seam 12, more than one thread 114 may be used for the stitch and preferably at least two rows 130 of the thread are stitched through each of the first edge and second edge portions 108, 110, with the illustrated embodiment having three rows 130 of stitched thread 114.

[0109] Advantageously, the sewn seam 12 between the first edge portion 108 and the second edge portion 108 can be sealant-free and adhesive-free; and instead, the free fibers 112 are used to plug and effectively seal the holes created by the stitching of the thread 114.

[0110] Testing shows that the 3-ply woven fiberglass seam seal provided by seam tape 1 16 can enable the sewn seam 12 to have emissions equal to or less than the laminated filter fabric, i.e. sewn seam does not contribute to higher emissions.[OHl] To make such a filter such as the filter bag 10, a method of making a filter, comprising: overlapping the first edge portion 108 and the second edge portion 110 of the filter media 100. For example, this may be done in order to create the tubular sleeve 14 or closed end 18. Further, the method involves overlapping the seam tape 116 upon the first edge portion 108 and the second edge portion 110, with the seam tape 116 providing comprising a layer of fibers 112. Further, the method involves stitching the thread 114 through each of the first edge portion 108, the second edge portion 110. and the seam tape 116. As a result of the stitching, the method further involves pulling at least some fibers 112 from the seam tape 116 into the filter media 100 to seal (i.e., at least partially plug openings) between the thread 114 and the filter media 100, so as to improve the filtration efficiency at the sewn seam 12.

[0112] Often in such method, the prior to overlapping the seam tape 116, the method involves laminating the support layer 102 and the filtration layer 104 together to provide the filter media 100.

[0113] Finally, while a seam tape 116 is a convenient way to provide a supply and layer of available fibers that can plug holes during stitching and threading, other alternative ways to provide such a supply and layer of available fibers are disclosed in the following two paragraphs that can be used by themselves or together, which may avoid the need for a seam tape 116.

[0114] In an embodiment, the method may comprise locally mobilizing fibers from the filter media proximate at least one of the first edge portion and the second edge portion to generate a supply of available fibers. For example, one or both edge portions may be roughened prior to stitching and / or overlapping. Fibers from the filter media proximate at least one of the first edge portion and the second edge portion by being loosened or mobilized locally within the support layer by mechanical means including use of air jets, water jets, brushes, needles, etc. Mobilization of fibers in the support layer w ould enablethe sealing of the seam in a similar manner to using loose fibers or the use of the fibrous seam tape.

[0115] In an embodiment, the method may comprise providing available fibers by applying loose fibers separate of any fabric over the filter media prior to stitching. An option of such loose fibers may be staple fibers that are often used for needle-felting, which could be applied at along at least one of the edge portions and would be useable and similarly pulled during threading and stitching of the bag seal. Another option of loose fibers would be chopped glass fibers that could be applied at along at least one of the edge portions and would be useable and similarly pulled during threading and stitching of the bag seal.

[0116] All references, including publications, patent applications, and patents cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

[0117] The use of the terms “a” and “an” and “the7’ and similar referents in the context of describing the invention (especially in the context of the following claims) is to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including.” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any nonclaimed element as essential to the practice of the invention.

[0118] Preferred embodiments of this invention are described herein, including the best mode know n to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary' skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law'. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.

Claims

WHAT IS CLAIMED IS:

1. A filter compri sing : a filter media comprising a support layer and a filtration layer attached thereto by a lamination therebetween, the filter media comprising a first edge portion and a second edge portion arranged adjacent in an overlapping relation; a layer of fibers are provided at the overlapping relation between the first edge portion and the second edge portion; a thread stitched through each of the first edge portion and the second edge portion, wherein some of the fibers project into the filter media to reside between the thread and the filter media.

2. The filter of claim 1, further comprising: a seam tape providing at least one fibrous seam layer comprising the layer of fibers, with the seam tape overlapping the first edge portion and the second edge portion.

3. The filter of claim 2, wherein the seam tape is provided by a strip of fabric that is folded into overlapping relation upon itself.

4. The filter of claim 3, the strip is folded to provide at least three fibrous seam layers overlapping upon the first edge portion and the second edge portion.

5. The filter of claim 4, wherein the strip is a texturized fabric having a texturized side with a greater amount of texturized yams exposed on one side of the texturized fabric, wherein folds of the strip are arranged such the texturized side along at least two of the fibrous seam layers are positioned facing the filter media, and the texturized side along one of the fibrous seam layers is in contact with the filter media.

6. The filter of claim 2, wherein the seam tape comprises at least one woven or non-woven media selected from the following group of: a fiberglass, a polyester, a polypropylene, a fluoropolymer, an acrylic, an aramid, a polyphenylene sulfide (PPS), and / or a polyimide.

7. The filter media of claim 2. wherein some of the fibers of the fibrous seam tape are mechanically pulled through both of the first edge portion and the second edge portion.

8. The filter media of claim 1. wherein the layer of fibers comprises loose fibers of a non-fabric material.

9. The filter media of claim 8, wherein the loose fibers are applied in a localized region over the filter media.10 The filter media of claim 1 wherein the layer of fibers are provided by a localized region of loose fibers mobilized off of the support layer, the loose fibers being looser in the localized region than a remainer of the support layer.

11. The filter of claim 1, wherein the overlapping relation creates a felled seam, a lapped seam, an overlap seam, a butt seam, or a hem.

12. The filter of claim 1, wherein the fibers are provided by an overlay media having variable fiber mobility, with a higher fiber mobility on one side as compared to the other side.

13. The filter of claim 1. wherein tire layer of fibers are provided by a texturized fabric having a texturized side with a greater amount of texturized yams exposed on one side of the texturized fabric, wherein at least a portion of the texturized side of the fabric is positioned facing and in contact with the filter media.

14. The filter of claim 1, wherein the support layer comprises at least one woven or non-woven media selected from the following group of: a fiberglass, a polyester, a polypropylene, a fluoropolymer, an acry lic, an aramid, a polyphenylene sulfide (PPS), and / or a polyimide.

15. The filter of claim 1, wherein the filtration layer comprises at least one media selected from the following group of: an expanded fluoropolymer membrane, and a fine fiber polymer entanglement of polymeric fibers having an average fiber size of less than 5 micron and preferably less than 1 micron.

16. The filter of claim 1, wherein the support layer comprises: a thickness of between 0 and 3 millimeters, more preferably between 0.2 and 1.5 millimeters, and a basis weight of up to 1700 grams / square meter, and more preferably between 300 and 850 grams / square meter; and wherein the filtration layer comprises: a thickness of between 1 and 72 micron, more preferably between 4 and 30 micron, and a basis weight of betw een 0.2 and 8.4 grams / square meter, and more preferably between 1 and 7 grams / square meter.

17. The filter of claim 1, wherein the support layer comprises a woven fiberglass substrate, wherein the filtration layer comprises an expanded fluoropolymer membrane, and wherein the fibers are provided by texturized fiberglass yams.

18. The filter of claim 14, wherein the texturized fiberglass yams are provided by a fiberglass fabric layer that is preferably woven, the texturized fiberglass yams separately provided from the first edge portion and a second edge portion.

19. The filter of claim 1, wherein at least two rows of the thread are stitched through each of the first edge portion and the second edge portion.

20. The filter of claim 1, wherein at least some fibers project entirely through first edge portion and the second edge portion and exposed to opposite sides of the filter media and plug holes around the thread.

21. The filter of claim 1, wherein a seam between the first edge portion and the second edge portion are sealant-free and adhesive-free.

22. The filter of claim 1, wherein the filter media has an efficiency of at least MERV 8, and more preferably at least MERV 14, as defined by ASHRAE 52.2-2017.

23. A bag filter comprising the filter of claim 1 configured into a sleeve having an open end and a closed end.

24. A filter comprising: a filter media comprising a first edge portion and a second edge portion arranged adjacent in overlapping relation; a seam tape providing at least one fibrous seam layer comprising a layer of fibers, with the seam tape overlapping the first edge portion and the second edge portion; a thread stitched through each of the first edge portion, the second edge portion, and the seam tape, wherein some of the fibers from the seam tape reside between the thread and the filter media.

25. The filter of claim 24, wherein the seam tape is provided by a strip of fabric that is folded into overlapping relation upon itself to provide at least two fibrous seam layers overlapping upon the first edge portion and the second edge portion.

26. The filter of claim 25. wherein the strip is a texturized fabric having a texturized side with a greater amount of texturized yams exposed on one side of the texturized fabric, wherein the texturized side along one of the fibrous seam layers is in contact with the filter media.

27. The filter of claim 24, wherein the seam tape comprises at least one woven or non-woven media selected from the following group of: a fiberglass, a polyester, a polypropylene, a fluoropolymer, an acrylic, an aramid, a polyphenylene sulfide (PPS). and / or a polyimide.

28. The filter media of claim 24, wherein some of the fibers of the fibrous seam tape are mechanically pulled through both of the first edge portion and the second edge portion.

29. The filter of claim 24, wherein the overlapping relation creates a felled seam, a lapped seam, an overlap seam, a butt seam, or a hem.

30. The filter of claim 24, wherein the support layer comprises at least one woven or non-woven media selected from the following group of: a fiberglass, a polyester, a polypropylene, a fluoropolymer, an acrylic, an aramid, a polyphenylene sulfide (PPS), and / or a polyimide.

31. The filter of claim 24, wherein the filtration layer comprises at least one media selected from the following group of: an expanded fluoropolymer membrane, and a fine fiber polymer entanglement of polymeric fibers having an average fiber size of less than 5 micron and preferably less than 1 micron.

32. The filter of claim 24. wherein the support layer comprises: a thickness of between 0 and 3 millimeters, more preferably between 0.2 and 1.5 millimeters, and a basis weight of up to 1700 grams / square meter, and more preferably between 100 and 850 grams / square meter; and wherein the filtration layer comprises: a thickness of between 1 and 72 micron, more preferably between 4 and 30 micron, and a basis weight of between 0.2 and 8.4 grams / square meter, and more preferably between 1 and 7 grams / square meter.

33. The filter of claim 24. wherein the support layer comprises a woven fiberglass substrate, wherein the filtration layer comprises an expanded fluoropolymer membrane, and wherein the fibers are provided by texturized fiberglass yams.

34. The filter of claim 24. wherein at least some fibers project entirely through first edge portion and the second edge portion and exposed to opposite sides of the filter media and plug holes around the thread.

35. The filter of claim 24, wherein a seam between the first edge portion and the second edge portion are sealant-free and adhesive-free.

36. The filter of claim 24, wherein the filter media has an efficiency of at least MERV 8, and more preferably at least MERV 14, as defined by ASHRAE 52.2-2017.

37. A bag filter comprising the filter of claim 24 configured into a sleeve having an open end and a closed end.

38. A method of making a filter, comprising: overlapping a first edge portion and a second edge portion of a filter media; providing a supply of available fibers at the first and second edge portions; stitching a thread through each of the first edge portion, the second edge portion, and the available fibers; and pulling at least some fibers from the available fibers during the stitching into the filter media to seal between the thread and the filter media.

39. The method of claim 38, further comprising: laminating a support layer and a filtration layer together to provide the filter media.

40. The method of claim 38, wherein said providing comprises overlapping a seam tape upon the first edge portion and the second edge portion, the seam tape comprising a layer of fibers providing the available fibers.

41. The method of claim 40, further comprising: folding the seam tape upon itself to provide multiple layers of the fibers overlapping the first edge portion and the second edge portion.

42. The method of claim 40, wherein the seam tape is provided by a texturized fabric having a texturized side with a greater amount of texturized yams exposed on one side of the texturized fabric, and further comprising: arranging at least a portion of the texturized side of the fabric to be facing and in contact with the filter media for stitching.

43. The method of claim 40, wherein the seam tape comprises at least one woven or non-woven media selected from the following group of: a fiberglass, a polyester, a polypropylene, a fluoropolymer, an acrylic, an aramid, a polyphenylene sulfide (PPS), and / or a polyimide: wherein the support layer comprises at least one woven or non-woven media selected from the following group of: a fiberglass, a polyester, a fluoropolymer, an acrylic, an aramid, a polyphenylene sulfide (PPS), and / or a polyimide; and wherein the filtration layer comprises at least one media selected from the following group of: an expanded fluoropolymer membrane, and a fine fiber polymer entanglement of polymeric fibers having an average fiber size of less than 5 micron and preferably less than 1 micron.44 The method of claim 38, further comprising locally mobilizing fibers from the filter media proximate at least one of the first edge portion and the second edge portion to generate a supply of available fibers.

45. The method of claim 38, wherein the available fibers are provided by applying loose fibers separate of any fabric over the filter media prior to stitching.

46. The method of claim 38, further comprising configuring the filter media into a filter bag with the stitching.

47. A filter, comprising: a. woven fiberglass filter media including two adjacent edge portions in overlapping relation; and b. a multilayered fiberglass seam tape layered lengthwise along the adjacent edge portions and needle stitched with the overlapping edge portions to define a seam, wherein fibers of the seam tape are forced into needle openings as the seam tape is stitched to the filter media.

48. The filter as in claim 47, wherein the seam tape is a folded strip of three adjacent lengthwise-extending layers.

49. A method for forming a seam along a woven fiberglass filter bag, comprising the steps of: a. bringing edge portions of the filter bag into adjacent, overlapping relation; b. layering a multilayered fiberglass seam tape lengthwise along the overlapping edge portions of the filter bag; andc. stitching through the seam tape and through the overlapping edge portions with a needle to form a seam.

50. The method as in claim 49, further including the step of folding the strip of seam tape into three adjacent lengthwise extending layers prior to layering the seam tape along the overlapping edge portions of the fdter bag, the needle forcing fibers the seam tape into openings in the overlapping edge portions created by the needle during stitching to form the seam.

51. A filter, comprising: a. woven fibrous filter media including two adjacent edge portions in overlapping relation; and b. a multilayered fibrous seam tape layered lengthwise along the adjacent edge portions; and c. the seam tape needle-stitched to the overlapping edge portions with fibers of the seam tape forced into openings in the overlapping edge portions created by the needle during stitching to form a seam.

52. The filter as in claim 51 , wherein the seam tape is a folded strip of three adjacent lengthwise-extending fibrous layers.

53. The filter as in claim 52, wherein the seam is adhesive-free.

Images