A pleated filter element comprising a pleated filter medium

Abstract

A filter element is presented that includes a pleated filter media that includes an upstream major face and a downstream major face, and that includes a plurality of pleats having a pleat direction and having a plurality of upstream pleat tips and upstream valleys and a plurality of downstream pleat tips and downstream pleat valleys. The pleated filter media includes a single layer of a nonwoven web that includes melt-blown polymeric fibers having a fiber solids of at least 10% and an effective fiber diameter of at least 2 µm. The pleated filter media is self-supporting.

Description

Background Technology

[0001] Respirators are typically used to clean the air that will be breathed by the user and often include a mask body and one or more filter elements fluidly connected to the mask body. Summary of the Invention

[0002] A filter element is proposed, comprising a pleated filter media including an upstream main surface and a downstream main surface, and including multiple pleats having a pleating direction and having multiple upstream pleat tips and upstream valleys, as well as multiple downstream pleat tips and downstream pleat valleys. The pleated filter media comprises a single-layer nonwoven web comprising meltblown polymer fibers having a fiber solids content of at least 10% and an effective fiber diameter of at least 2µm. The pleated filter media is self-supporting.

[0003] The foregoing description of this invention is not intended to describe every disclosed embodiment or every specific implementation of this disclosure. The following description illustrates exemplary embodiments in more detail. Therefore, it should be understood that the following description should not be construed as an undue limitation on the scope of this disclosure. Attached Figure Description

[0004] Figure 1 The embodiments described herein are illustrated as useful exemplary reusable respirators.

[0005] Figures 2A to 2B Examples of glass fiber and polymer filter media are shown respectively.

[0006] Figures 3A to 4D A pleated media in a filter element according to an embodiment of this article is illustrated.

[0007] Figures 5A to 5C Example filter elements and their housings according to embodiments of this document are illustrated.

[0008] Figure 6 A method for manufacturing a pleated bag according to the embodiment described herein is illustrated.

[0009] In all figures, the same reference numerals indicate the same elements. Some elements may be present in the same or equal multiples; in such cases, one or more representative elements may be designated only by reference numerals, but it should be understood that such reference numerals apply to all such identical elements. Unless otherwise indicated, all illustrations and figures in this document are not drawn to scale and are selected for the purpose of illustrating different embodiments of the invention. Specifically, unless otherwise indicated, the dimensions of various parts are depicted only using illustrative terms, and no relationship between the dimensions of the various parts should be inferred from the figures. Detailed Implementation

[0010] Although terms such as “top,” “bottom,” “upper,” “lower,” “below,” “above,” “upward,” and “downward,” as well as “first” and “second” may be used in this invention, it should be understood that, unless otherwise specified, those terms are used only in their relative meanings. As used herein, as a modifier of a characteristic or attribute, unless otherwise specifically defined, the term “generally” means that the characteristic or attribute will be readily identifiable by a person skilled in the art without requiring absolute precision or a perfect match (e.g., within + / -20% for quantifiable characteristics). Unless otherwise specifically defined, the term “substantially” means a high degree of approximation (e.g., within + / -10% for quantifiable characteristics), but again, absolute precision or a perfect match is not required. The term “substantially” means an extremely high degree of approximation (e.g., within + / -2% for quantifiable characteristics); it should be understood that the phrase “at least substantially” includes specific cases of “precise” matching. However, even a “precise” match, or any other characteristic described using terms such as identical, equal, consistent, uniform, constant, etc., will be understood as being within normal tolerances or within measurement errors applicable to a particular situation, rather than requiring absolute precision or a perfect match.

[0011] The term "upstream" is used to refer to the side of the entity through which the flowing air impacts (e.g., a pleated air filter); the term "downstream" is used to refer to the side of the entity through which the air exits the entity. Terms such as inward, outward, outermost, etc., are relative to the upstream-downstream direction of the pleated air filter. The term "lateral" and terms such as, for example, "lateral inward," are relative to the direction along the pleats of the pleated air filter, as discussed in detail herein.

[0012] Terms such as “closed” or “enclosed” mean a barrier that prevents at least, in large part, air from flowing through it.

[0013] Figure 1 The embodiments described herein are illustrated as useful exemplary reusable respirators. Figure 1 An individual 100 wearing a half-face reusable respirator 102 is illustrated. The respirator is configured to be attached to one or more pleated pouches 110, each pouch containing a pleated filter medium. Figure 1 (Not shown in the image).

[0014] However, although Figure 1The illustrations herein depict a half-face reusable respirator (e.g., a reusable respirator that covers only half of an individual's face 100), but it is clearly envisioned that the embodiments described herein can be more broadly applied to powered air-purifying respirator (PAPR) filters and other types of reusable respirators, such as, for example, full-face respirators.

[0015] The filter element inside the pleated bag 110 is important for both user comfort and safety. The filter element is designed to filter particulate matter from ambient air. From a safety perspective, a filter element with sufficient filtration and load capacity is desirable. From a comfort perspective, a filter element with a low pressure drop across the filter media is desirable. Pressure drop is related to the user's ability to breathe through the filter element.

[0016] As illustrated in Figures 3 and 4, a pleated medium refers to a filter element that has been pleated (e.g., repeatedly folded into a zigzag or accordion shape). The pleated filter element is then placed inside the housing of the respirator, and air is forced through the filter element by the user breathing (in a reusable respirator) or by a motor and fan (PAPR).

[0017] The purpose of pleating the fiber elements is to increase the surface area and particle load of the filter element available for filtration. However, the pleated media must be formed to allow air to flow through as much filter media as possible without obstruction. If adjacent pleats close the airflow passage, the pressure drop increases and the available surface area of ​​the filter media decreases.

[0018] Typically, pleated filter media are designed such that when pleated, they (1) maintain sharp fold lines and (2) are self-supporting. Fiberglass is an example material that satisfies both requirements—it partially breaks when pleated (e.g., Figure 2A (as seen in the text), and is a stiff material that can produce self-supporting folded media.

[0019] However, glass fiber as a filter media has some undesirable characteristics. Glass fiber filter media are brittle and easily broken. Additionally, filter media formed from glass fiber can be treated to be oil-resistant, for example, to meet any of the NIOSH R95, P95, P99, and / or P100 classifications or similar standards in other jurisdictions. Oil-resistant treatments typically involve fluorination, which is undesirable.

[0020] A filter media is desired that is less brittle and less prone to breakage than glass fiber materials, and meets oil resistance regulations without the use of fluorinated materials or fluorination treatments. A filter media with low permeability and pressure drop is also desired, while meeting permeability, load, and stiffness requirements.

[0021] There is also a desire for a filter medium that can meet these requirements with a single-piece medium, which reduces the complexity of the manufacturing process. Figures 2A to 2B Examples of glass fiber and polymer filter media are shown respectively. Figure 2A The example is a glass fiber material 210, which has broken along the fold line 212 after being scored. Figure 2B An example is a polymer blown microfiber filter medium 220, which does not break along the fold line 222.

[0022] A filter medium that meets these requirements without requiring a coating process is also desired. The self-supporting filter medium according to embodiments herein is a monolithic medium without coating. For example, U.S. Patent No. 12,030,006, published July 9, 2024, describes a self-supporting filter medium that includes a binder component as part of the filter medium. Embodiments of the self-supporting medium described herein do not contain binder materials and comprise nonwoven fibers formed into a pleated structure. Similarly, in another example, U.S. Patent No. 11,819,793, published November 21, 2023, describes a filter cartridge with a filter layer having a cured reinforcing agent to maintain the pleated form. Embodiments of the self-supporting medium described herein do not contain binder materials, reinforcing agents, or laminates.

[0023] The filter media according to the embodiments described herein is formed of a single layer of nonwoven material, which is rigid enough to be self-supporting when pleated into a pleated pouch construction. Many filter media previously used in pleated pouch constructions require separate reinforcing elements. For example, the filter media may have been laminated, welded, or thermally bonded to a loose fabric or reinforcing element. The reinforcing element may be, for example, a woven material, a nonwoven material, or a metal. Multilayer filter media constructions can be joined together by lamination, by ultrasonic or other welding techniques, thermal bonding, or the use of adhesives. According to the embodiments described herein, the filter media does not undergo a lamination step with another, harder material. The filter media of this invention comprises a single material layer that is joined to another separate material layer without any welding, bonding, or adhesive treatment.

[0024] According to embodiments described herein, forming a pleated package may include applying an adhesive to the pleated media, for example, to form edge baffles or to seal the filter media to the inner surface of the filter cartridge. However, it should be explicitly stated that the filter media described herein are self-supporting prior to using an adhesive to form edge baffles or to seal the filter media to the interior of the filter cartridge housing.

[0025] Nonwoven blow-molded microfiber polymer-based electret filter materials offer several advantages over glass fiber media. The polymer filter material can be quasi-permanently charged, for example, using the method described in U.S. Patent No. 5,496,507, issued March 5, 1996 (incorporated herein by reference), or using similar methods. Filter-grade glass fibers are typically uncharged and may have a limited ability to retain charge. Uncharged filter materials typically operate based on mechanical filtration—for example, the filter media fibers are woven or formed densely enough that particles are trapped across the entire depth of the filter media. Charging the filter media causes the fibers of the filter media to trap particles through an additional mechanism of electrostatic attraction. Because the particles are trapped within the filter media by this additional trapping mechanism, it is also possible to form a filter media that maintains the same filtration efficiency with a lower pressure drop.

[0026] However, traditionally, polymer filter media are soft and flexible, which limits the ability to densely pleat them within pleats. This can be addressed by adding a stiffening material to the filter media to achieve the desired stiffness. However, it is desirable to densely pleat polymer filter media without adding a layer of stiffening material.

[0027] exist Figure 3A and Figure 3B The comparison illustrates the importance of sharp fold lines and self-supporting structures. Figure 3A In this process, the nonwoven polymer electret material 300 is pleated. The polymer material forms rounded pleat tips 310 due to its low stiffness and flexibility. It is desirable for ambient air to flow through all available channels created by the pleating process. However, as illustrated by reference numeral 320, approximately half of the channels are at least partially closed. Ambient air can flow more easily through channel 314 than through channel 312.

[0028] In comparison, Figure 3B An example of a filter medium according to an embodiment of this document is illustrated, exhibiting a sharp tip 360 when pleated, wherein most air passages are not blocked, as illustrated in passages 362 and 364. As used herein, the sharpness of the tip 360 refers to the radius of curvature at the tip of the pleat. A sharp tip is defined as having a radius of curvature less than half the distance between pleats (e.g., a curvature diameter less than the width of each pleat). When the radius of curvature is greater than half the distance between pleats, blockage of the air passages is more likely to occur.

[0029] The embodiments described herein include a filter element comprising a monolithic polymer filter media capable of forming sharp folds and being self-supporting when pleated. According to the embodiments described herein, the monolithic filter media is formed of a rechargeable polymer material.

[0030] The embodiments described herein include filter elements formed from a single sheet of non-laminated media, which possess uniform or consistent mechanical properties across the entire thickness of a self-supporting polymer web when pleated. The embodiments described herein include filter media with a lower basis weight than other polymer filter media materials while maintaining sufficient stiffness to self-support when pleated. The lower basis weight allows for a higher number of pleats (e.g., more folds of the filter media), which reduces pressure drop across the filter element.

[0031] In some embodiments described herein, the filter media is composed of meltblown polypropylene material with suitable charged additives. In some embodiments, the filter material described herein may have a concentration between 60 g / m². 2 The basis weight is between 70 gsm and 100 gsm. In some implementations, the basis weight is between 70 gsm and 100 gsm.

[0032] In some embodiments described herein, the filter media may have a thickness between 300 µm and 500 µm, and is composed of fibers with an effective fiber diameter between about 2 µm and about 8 µm and a fiber solids content of 10%-18%.

[0033] "Solids ratio" is a nonwoven web characteristic that is inversely related to density and web permeability and porosity (low solids ratio corresponds to high permeability and high porosity), and is defined by the following Equation 1.

[0034]

[0035] Equation 1

[0036] The filter media according to embodiments of this invention may have a Gluttony concentration between 100 mg and 1000 mg, depending on some embodiments. In some embodiments, the filter media has a Gluttony concentration of at least about 100 mg. In some embodiments, the filter media has a Gluttony concentration of at least about 150 mg. In some embodiments, the filter media has a Gluttony concentration of less than 1000 mg. In some embodiments, the filter media has a Gluttony concentration of less than about 550 mg. In some embodiments, the filter media has a Gluttony concentration between 150 mg and 350 mg.

[0037] The filter media according to the embodiments of this invention may have a pleat density of at least 7 pleats / inch. The filter media according to the embodiments of this invention may have a pleat density of at least 8 pleats / inch. The filter media according to the embodiments of this invention may have a pleat density of at least 9 pleats / inch. The filter media according to the embodiments of this invention may have a pleat density of at least 10 pleats / inch. The filter media according to the embodiments of this invention may have a pleat density of at least 11 pleats / inch. The filter media according to the embodiments of this invention may have a pleat density of at least 12 pleats / inch. The filter media according to the embodiments of this invention may have a pleat density of at least 13 pleats / inch. The filter media according to the embodiments of this invention may have a pleat density of at least 14 pleats / inch. The filter media according to the embodiments of this invention may have a pleat density of at least 15 pleats / inch.

[0038] In some embodiments herein, the filter media has low permeability, determined at a surface velocity of 13.8 cm / s using the percentage permeability test method described in the following examples, quantified as less than 0.01%, or even less than 0.001%. In some embodiments herein, the filter media may have a pressure drop between 3 mmH2O and 50 mmH2O at a surface velocity of 13.8 cm / s. In some embodiments herein, the filter media has a quality factor greater than 0.3 at a surface velocity of 13.8 cm / s.

[0039] The combination of stiffness and flatness in media filtration allows monolithic filter media, according to the embodiments described herein, to form a self-supporting pleated filter structure.

[0040] Figures 4A to 4D Examples of pleated bags and associated filter media according to embodiments herein are shown.

[0041] Figure 4A A perspective view is illustrated from the upstream side of an exemplary pleated filter element 401 including pleated air filter media 410. According to an embodiment, the pleated air filter media 410 is a monolithic medium having fibers with an effective diameter between about 2 µm and about 8 µm. In some embodiments, the monolithic medium has fibers with an effective diameter between about 4 µm and about 6 µm. The fibers of the pleated air filter media 410 have a fiber solids content between about 9% and 18%. The pleated air filter media 410 has a basis weight between about 50 gsm and about 120 gsm. In some embodiments, the sheet of filter media has a basis weight between about 50 gsm and about 100 gsm. Before pleating, the monolithic air filter media has a thickness between about 0.3 mm and about 1.2 mm. In some embodiments, the monolithic air filter media has a thickness between about 0.3 mm and about 0.5 mm.

[0042] When pleated, filter element 401 can be characterized as having pleats with a pleat height between about 6 mm and 23 mm or between 10 mm and 23 mm. The pleat height can vary depending on the application. Filter element 401 is pleated such that the pleat density is between about 7 pleats / inch and 15 pleats / inch.

[0043] A respirator incorporating a filter medium according to an embodiment of this document can be characterized to have a pressure drop between about 3 mmH2O and 50 mmH2O at 85 L / min. A respirator incorporating the filter medium described herein can be characterized to have a permeability of less than 0.001% at 85 L / min (when evaluated using dioctyl phthalate or DOP aerosol measured according to the procedure disclosed in the working examples).

[0044] The respirators comprising filter media described in this embodiment can filter at least 95% of airborne particles with an average diameter of 0.3 µm when worn correctly. In some embodiments, such respirators can filter at least 99% of airborne particles with an average diameter of 0.3 µm when worn correctly. In some embodiments, such respirators can filter at least 99.97% of airborne particles with an average diameter of 0.3 µm when worn correctly. In some embodiments, such respirators of this embodiment at least partially resist oily aerosol particles with an average diameter of 0.3 µm.

[0045] Filter element 401 is formed by pleating air filter medium 410 using a suitable pleating process. Once pleated, the single sheet of air filter medium 410 is self-supporting without any additional reinforcing elements. Filter element 401 does not contain laminated elements; for example, pleats 420, 430 are formed individually from the single sheet of air filter medium 410. Filter element 401 does not contain glass fiber or any fluorinated materials.

[0046] A portion of the exemplary filter element 401 is in Figure 4B The image is shown in a side view. In some embodiments, the filter element 401 may be a rectangular shape (specifically including a square shape) having, for example, four corners; in such embodiments, the pleated filter media 410 may therefore have a generally rectangular perimeter (this does not exclude irregular portions, notches, chamfered corners, or angled corners in the perimeter of the filter media 410). The pleated filter media 410 (and filter element 401) includes a main edge, for example, such as... Figure 4A The four main edges are shown. Main edges (ends) 404 and 404' (which terminate as exposed folds) will be referred to herein as corrugated edges, and main edges (ends) 405 and 405' will be referred to as non-corrugated edges, all of which are as follows: Figure 4A As shown.

[0047] Filter element 401 includes an upstream main side 402 and a downstream main side 403; the pleated filter media 410 therefore includes an upstream main surface 425 and a downstream main surface 435. In some embodiments, filter element 401 may be upstream-downstream symmetrical (e.g., filter element 401 may be housed within a filter element housing where either main side is oriented upstream); in such cases, the names of the upstream and downstream sides / surfaces are interchangeable. However, in other embodiments, filter element 401 is not symmetrical in this manner, and the names of the upstream side and surface, as well as the downstream side and surface, are not interchangeable.

[0048] The pleated filter media 410 can be made of any suitable nonwoven organic polymer material. For example, any of polyethylene, polypropylene, poly(methylpentene), cycloolefin (COC), polyester (PET), or poly(lactic acid) can be suitable. In some embodiments, the filter media can be formed from at least some partially recycled material. Any suitable method for manufacturing the nonwoven web can be used to produce the fiber characteristics and properties of the filter media 410. In a particular embodiment, the nonwoven web can be a meltblown nonwoven web, meaning the fibers are meltblown and exhibit an effective fiber diameter (EFD) of less than about 10 µm. In some embodiments, the fibers exhibit an EFD of less than about 8 µm. In some embodiments, the fibers exhibit an EFD of less than about 6 µm.

[0049] In a specific embodiment, the pleated filter medium 410 is formed of an electret material. An electret material is a material (e.g., an organic polymer material) that exhibits a quasi-permanent charge after a suitable charging process. The charge can be characterized by, for example, an X-ray discharge test disclosed in U.S. Patent Publication 2011-0290119. This material can be selected from any suitable material, such as separated fibrillated charged fibers as described in U.S. Patent RE 30782. Such charged fibers can be formed into a nonwoven web by any suitable means, such as that disclosed in U.S. Patent 5,230,800. In other specific embodiments, the filter medium 410 can be a meltblown microfiber nonwoven web that may include at least some of the electret fibers (e.g., the general type disclosed in U.S. Patents 4,215,682 and 7,989,371). Filter media that may be particularly suitable for certain applications may include: media of the general type described, for example, in U.S. Patent 8,162,153 granted to Fox; and media generally referred to as triboelectric media. If needed, any such medium can be charged to provide a charged electret portion.

[0050] Any suitable charging method can be used, selected from, for example, corona charging, water charging, tribocharging, etc. In some embodiments, the filter medium may be formed from pre-charged electret fibers; or, the filter medium may be formed (e.g., collected as a nonwoven web and combined (if desired) or formed as a membrane) and then post-charged. If desired, the medium may include one or more charging additives, such as any of the additives described in International Patent Publication WO2016 / 033097, published on March 3, 2016.

[0051] In various embodiments, any such filter media may exhibit a thickness of less than about 1.2 mm. In some embodiments, the filter media exhibits a thickness of less than about 1.0 mm. In some embodiments, the filter media exhibits a thickness of less than about 0.5 mm. In some embodiments, the filter media exhibits a thickness between about 0.3 mm and 0.5 mm. In various embodiments, any such filter media may exhibit a thickness of at least about 50 g / m². 2 ), 70g / m 2 Or 80g / m 2 Up to approximately 120g / m 2 Or 100g / m 2 The basis weight. In various embodiments, the medium may exhibit a water pressure drop greater than about 10.0 mm or 15.0 mm (measured according to the process disclosed in the working embodiment). In other embodiments, the medium may exhibit a water pressure drop less than about 60 mm, 50 mm, 40 mm, or 30 mm. In various embodiments, the medium may exhibit a percentage permeability less than about 1.0%, 0.1%, 0.05%, 0.01%, or 0.001% at a surface velocity of 13.8 cm / s (i.e., the initial percentage permeability of DOP, measured according to the process disclosed in the working embodiment).

[0052] The stiffness of the media can be characterized by Grylls stiffness (measured as described in the working examples herein). In various embodiments, filter media as disclosed herein may exhibit a Grylls stiffness (measured individually) of at least about 150 mg, or even at least about 200 mg, or even at least about 250 mg, or even at least about 300 mg, or even at least about 350 mg, or even at least about 400 mg, or even at least about 450 mg, or even at least about 500 mg, or even at least about 550 mg. In some embodiments, filter media as disclosed herein may exhibit a Grylls stiffness of at least about 600 mg, or at least about 700 mg, or even at least about 800 mg, or even at least about 900 mg. In some embodiments herein, the filter media exhibits a Grylls stiffness of less than about 1000 mg. In some embodiments herein, the filter media exhibits a Grylls stiffness of less than about 550 mg. In some embodiments herein, the filter media exhibits a Grylls stiffness of less than about 350 mg.

[0053] Pleated filter media

[0054] As described above, the filter medium 410 is pleated. In at least some embodiments, the pleated filter medium 410 does not include any type of planar reinforcement structure or support layer (e.g., multiple particleboard strips, a layer of wire mesh, nonwoven fabric, etc.) bonded to the pleat tips on the main side of the pleated filter medium to stabilize the pleat spacing. Furthermore, in at least some embodiments, the pleated filter medium 410 does not include any kind of protective layer or support layer (e.g., wire mesh, polymer mesh, or nonwoven fabric) pleated together with the pleated filter medium and does not perform a filtration function (e.g., exhibiting a percentage permeability greater than 99.0%). Therefore, in some embodiments, the filter element 401 may consist essentially of or comprise a pleated filter medium including an organic polymer nonwoven layer, without any pre-filter layer, reinforcement layer, or any other component layer. In some embodiments, the pleats of the filter medium 410 do not have any dents of the type described, for example, in U.S. Patent 5,427,597.

[0055] like Figure 4A and Figure 4BAs shown, the pleated filter media 410 includes a plurality of upstream pleats 420 and downstream pleats 430. Each upstream pleat 420 includes an upstream pleat tip 421, and each adjacent pair of upstream pleats 420 defines an upstream pleat valley 422 between them. The downstream pleats 430 are constructed opposite to the upstream pleats 420. Each downstream pleat 430 includes a downstream pleat tip 431, and each adjacent pair of downstream pleats 430 defines a downstream pleat valley 432 between them. As used herein, the pleat direction ( Figure 4C D in p The lateral direction (also known as the longitudinal direction) is the direction aligned with the long axis of the pleat tip (and typically extends from one corrugated edge 404 of the pleated filter media to the other corrugated edge 404'). The longitudinal direction (D in Figure 3C) l The upstream-downstream direction is orthogonal to the pleating direction and typically extends from one non-corrugated edge 405 of the pleated filter media to another non-corrugated edge 405'. (Although the terms longitudinal and lateral are used herein for ease of description, it is not absolutely necessary that the longitudinal dimension of the pleated filter media 410 be larger than the lateral (pleating direction) dimension of the pleated filter media 410.) Figure 4C D in u-d The direction of the airflow through the filter element is from the upstream side 402 to the downstream side 403, and generally corresponds to the overall direction of the airflow through the filter element.

[0056] refer to Figure 4C Side view (where D along the fold direction) p To further discuss the details of the pleated geometry, observe a portion of an exemplary pleated air filter medium 410 (where the adhesive baffle described later is omitted for clarity). The pleat spacing, pleat height, and pleat distance defined herein are evaluated using the pleated air filter medium 410 in a nominally planar configuration, wherein the pleated filter medium 410 exhibits an easily identifiable overall principal plane (although there are local deviations from this plane inherent in each pleat), such as... Figure 4C As shown. The pleat height (pleat amplitude) is along a direction orthogonal to the overall principal plane of the filter medium 410 (i.e., along the upstream-downstream direction D of the pleated medium). u-d The distance from the tip of the first side fold 421 to the tip of the second side fold 431 (alignment direction) Figure 4C P in hIn various embodiments, the fold height of the medium 410 may be at least about 2 mm, 4 mm, 6 mm, 8 mm, or 10 mm, or 12 mm. In other embodiments, the fold height may be at most about 45 mm, 40 mm, 35 mm, 30 mm, 25 mm, 20 mm, 15 mm, 12 mm, 10 mm, 8 mm, or 6 mm. In a particular embodiment, the folded medium may exhibit a regularly varying fold height, such as a predetermined alternating pattern of lower and higher fold heights.

[0057] fold spacing ( Figure 4C P in s ) is along the direction aligned with the overall main plane of the filter media (i.e., along the longitudinal direction D of the pleated media). l The distance between the nearest ipsilateral pleat tips. The pleated filter media 410 can have any suitable pleat spacing.

[0058] The embodiments described herein include pleated filter media with sharp pleated tips. The sharp pleated tips are characterized in that the radius of curvature at the tip is less than half the distance between adjacent pleats. For example, the embodiments described herein have pleat widths greater than the diameter of curvature at the pleat tips.

[0059] In an embodiment where medium 410 is a tightly pleated type, the adjacent walls of the pleats are typically substantially parallel to each other, at least within a range of about 70%, 80%, or even 90% of the pleat height. This tightly pleated type of medium... Figure 4D It is presented in an idealized form.

[0060] The filter medium 410 can be pleated by any suitable method that provides a tight pleat spacing. In some embodiments, the medium can be scored to provide score lines, and if desired, the medium can be folded along these score lines to form very sharp pleat tips with a small radius of curvature. Such pleating operations, which can be conveniently performed, for example, by rotational scoring, generally result in score lines that are readily visible on at least one major portion of the filter medium 410 of the filter element 401. In some embodiments, both surfaces (upstream and downstream) of the filter medium 410 are rotated-scored to reveal score lines (it should be noted that any such score lines may be visible or not visible during periodic inspections of the pleated medium, and may require physical manipulation of the pleated medium (e.g., partial unfolding) to make the score lines visible). In some embodiments, pleating is performed using an ultrasonic pleating method, such as that described in U.S. Provisional Patent Application No. 63 / 779,099, filed March 27, 2025. The ultrasonic pleated filter media of the embodiments described herein may exhibit the same or similar properties as those described in the U.S. Provisional Patent Application.

[0061] U.S. Provisional Patent 63 / 779,009 describes a filter element comprising a pleated filter medium including a nonwoven web having polymer fibers and a plurality of pleated tips. The nonwoven web has recessed portions at at least some of the pleated tips and satisfies at least one of the following three conditions: 1) The recessed portions exhibit birefringence, while the nonwoven web does not exhibit birefringence at non-recessed portions. 2) The recessed portions have a retardation distribution, wherein there is an average retardation, and the average retardation is at least three times the average retardation at non-recessed portions. 3) The total porosity percentage of the recessed portions (as determined by X-ray microtomography) is less than 80% of the total porosity percentage of the nonwoven web at non-recessed portions. Figures 5A to 5C Example filter elements and their housings according to embodiments of this document are illustrated.

[0062] The above discussion focuses on the pleated filter media 410 and the pleated filter element 401, whose overall shape (ignoring local deviations due to pleating) is substantially flat (planar). However, in some embodiments, the pleated filter media and pleated filter element can be arc-shaped (e.g., Figure 5A (Exemplary embodiment shown in the side view). In a specific embodiment, the filter element 401 is manufactured as a flat surface and adapted to be arcuate in shape for mounting into an arcuate receiver within the filter element housing.

[0063] While the curved filter element may not be upstream-downstream reversible, it can offer other advantages, such as allowing the filter element housing to be bent to follow the contours of a user's cheek or hip. In some embodiments, the convex side of the curved filter element 401 is the upstream side 402, and the concave side of the curved filter element 401 is the downstream side, such as... Figure 5A As in the exemplary design.

[0064] In at least some embodiments, the arc-shaped pleated filter medium 10 will exhibit a shape with a single curvature, wherein the curvature is along a conformal axis A that is orthogonal to the pleat direction and parallel to the longitudinal direction. c ,like Figure 5A As shown. This type of construction will contrast with shapes exhibiting complex curvature, such as, for example, a portion of a sphere, parabola, or hyperboloid. This minimizes the possibility of any wrinkling or folding of the pleated medium when it is bent into an arc shape. It should be understood that such a single-curvature implementation will differ from forming complex composite curvature shapes to conform to, for example, a human face (e.g., in the body of a respirator mask).

[0065] In some embodiments, filter element 401 may include a housing, which is a separately manufactured component disposed on at least a portion of filter element 401 (e.g., fitted onto it, wrapped around it, etc.). If such a housing is present, it will be provided as part of filter element 401 and will not be removable from it during normal use of filter element 401. Therefore, such a housing is not part of the filter element housing, for example, a respirator. Such a housing may be made of any suitable material (e.g., molded plastic, cardboard, etc.). Such a housing is described in detail in U.S. Patent No. 10,751,660, published August 25, 2020, entitled [Title Missing]. In other embodiments, filter element 401 does not include any such housing.

[0066] Applications of filter elements

[0067] Filter element 401 can be used in any application where air filtration (the term generally covers any breathable gas mixture) is required.

[0068] In a particular embodiment, filter element 401 can be used in any suitable respirator configured for filtering breathing air. To include filter element 401 in a respirator, it can be conveniently housed within filter element housing 460, such as... Figures 5B to 5C The exemplary embodiments are shown. Filter element 401 and filter element housing 460 can be used with any type of respirator, such as powered or unpowered, full-face or half-face, etc. In various embodiments, such a respirator may include at least a mask body for defining an internal air space, the mask body including a portion that at least covers the user's nose and mouth (and may take the form of, for example, a helmet). An exhalation valve may be provided to allow exhaled air to be released from the internal air space. Such a respirator may also include a harness assembly capable of supporting the mask body on the user's head. In some embodiments, filter element housing 460 may be mounted close to the mask body. For example, a single filter element housing may be fluidly connected to the mask body, for example, at a location in front of the user's mouth and / or nose. Alternatively, dual filter element housings may be mounted, for example, at locations adjacent to the user's right and left cheeks. In other embodiments, one or more filter element housings may be positioned in a unit remote from the mask body, for example, positioned on, for example, a hip strap and including a power unit that actuates a fan through a supply tube to the mask body. Figures 5B to 5C The described filter element housing 460 is particularly suitable, for example, as a so-called powered air-purifying respirator (e.g., such as, under the trade name VERSAFLO). ™The TR-600 (a product purchased from 3M Company) is mounted on a hip strap. This powered air-purifying respirator delivers filtered air, for example, through a hose that fluidly connects the filter element housing 460 to the mask body or helmet located on the user's face or head. However, it should be emphasized that the filter element 401 can be housed in any suitable type of filter element housing.

[0069] The filter element housing 460 includes at least one main housing portion configured to receive at least one filter element 401 and fluidly connect the filter element to other components of the respirator (e.g., fluidly connect it to the mask body). The housing 460 (e.g., its main housing portion) may include an upstream main surface 61 including a breathable region 462 (which can be conveniently implemented by providing a plurality of through-holes in region 462 of the upstream surface 461 of the filter element housing 460, such as…). Figure 5B (As shown). In some embodiments, the housing 460 (e.g., at least one main housing portion thereof) may be made of an organic polymer resin molded (e.g., injection molding, vacuum forming, thermoforming, etc.) into a desired shape. (Other auxiliary parts, such as latches, fittings, etc., may be attached to the housing 460 as needed.)

[0070] In some embodiments, the filter element 401 can be discarded along with the filter element housing 460, making the housing 460 reusable when the filter element 401 needs to be replaced. In such embodiments, the filter element housing 460 is not part of the filter element 401 itself and is specifically removably attached to the filter element 401. In such cases, the housing 460 may include a closure portion ( Figures 5B to 5C (Not shown in the image) The closing portion is, for example, airtight and, when closed, serves to securely hold the filter element 401 in place within the interior 463 of the filter element housing 460. This closing portion may be hinged or snap-fitted to the housing 460, for example, so that the closing portion can be opened or temporarily removed, thereby removing the filter element 401 and installing a replacement filter element 401.

[0071] In other embodiments, the filter element 401 and the filter element housing 460 may be provided to the user as a unit, wherein the filter element 401 is non-removably attached to the housing 460. The housing 460, including the filter element 401, is removably attached to other components of the respirator to establish a fluid connection between the housing 460 and the respirator's mask body, allowing filtered air to be delivered to the mask body. In such embodiments, the housing 460, including the filter element 401, can be removed and discarded or recycled, and new housings and filter elements can be installed in the respirator at a desired time.

[0072] exist Figure 5C In an exemplary embodiment, the interior 463 of the housing 460 includes a receiver 464 configured to receive the filter element 401. Figure 5C In one exemplary embodiment, receiver 464 is arc-shaped to receive an arc-shaped filter element. However, it is explicitly contemplated that both filter element 401 and housing 460 can have different shapes; for example, housing 460 can be shaped to receive a flat filter, such as... Figure 4A The flat filter shown. Filters with flat or curved shapes can also have other shapes, such as oval, circular, polygonal or non-polygonal shapes, with, for example, straight and / or curved peripheral portions.

[0073] Receiver 464 may include sidewalls 465 and 467, with sidewall 465 abutting the non-corrugated edges 405 and 405' of the corrugated filter element 401 when installed within receiver 464, and sidewall 467 abutting the corrugated edges 404 and 404' of the corrugated filter element 401. In some embodiments, the longitudinal distance between sidewalls 465 may be set such that filter element 401 is slightly longitudinally compressed (accordion-pleated) to fit snugly within the space between longitudinal sidewalls 465. This arrangement helps to hold filter element 401 firmly in place without compressing the pleats of filter element 401 to the extent that it adversely affects filtration performance. In various embodiments, the longitudinal distance between longitudinal sidewalls 465 may be at most about 100%, 98%, 96%, or 94% of the longitudinal length of filter element 401 (before being compressed for installation in receiver 464).

[0074] If necessary, sealant or potting material (e.g., a curable material, such as RTV silicone, etc.) may be provided as beads along the corrugated edges 404 and 404' and / or along the non-corrugated edges 405 and 405' at locations, for example, on surfaces 466 of the sidewalls 467 and / or 465 of the housing 460, such as... Figure 5CAs can be seen. This material, after curing, minimizes any air leakage around the edges of the filter element 401. It should be understood that the presence of the inner edge baffle (specifically, the edge seal) of the filter element 401, as discussed herein, reduces or even eliminates the need to use this material along the sidewall 467 to minimize air leakage around the corrugated edges 404 and 404' of the filter element 401. If desired, this material can certainly be used to seal the non-corrugated edges 405 and 405' of the corrugated filter element against the sidewall 465 of the housing. Furthermore, even if sealing is not required, this material can be applied if needed to bond at least some portions of the edges of the filter element 401 to the surface of the receiver 464, for example, to more securely hold the filter element 401 in place within the housing 460.

[0075] In some embodiments, one or more gaskets (not shown in any figures) may be disposed within the interior 464 of the filter element housing 460 to facilitate secure mounting of the filter element 401 therein. Such gaskets may be permanently attached to the housing 460; or, if desired, may be removable and replaceable. These gaskets may be made of an elastic polymer material such as rubber, silicone, etc. The polymer material may be solid or foam. If foam, it may be open-cell or closed-cell foam. In some embodiments, such gaskets are not present.

[0076] In some embodiments, filter element 401 may be the only filter component located within filter element housing 460. However, in other embodiments, for some additional purpose, one or more layers of material may be located within housing 460 (e.g., in an overlapping relationship, such as mating the main surface of filter element 401). This one or more layers may contain one or more materials that interact with the airflow to at least partially remove one or more components (e.g., gases, vapors, solid particles, aerosols, etc.). Components in the fluid may be, for example, adsorbed onto or into an activated adsorbent, may react with reactive components, may be exposed to a catalyst, etc. Potentially suitable materials for such applications include: activated carbon, for example; alumina and other metal oxides; sodium bicarbonate; metal particles (such as silver particles) that can remove components from the fluid by adsorption, chemical reaction, or amalgamation; catalysts, such as hogallat and / or gold (which can catalyze the oxidation of carbon monoxide); clay and other minerals treated with acidic solutions (such as acetic acid) or alkaline solutions (such as aqueous sodium hydroxide solutions); ion exchange resins; molecular sieves and other zeolites; silica; biocides; fungicides and antivirals. Mixtures of any such materials can be used. In other embodiments, such materials can be provided as granules in a granular loaded web layer. Any combination of these methods can be used. If desired, such materials can be treated, for example, with one or more impregnating agents to improve gas removal capacity. Examples of treated materials include chemically surface-treated activated carbon.

[0077] In many embodiments, the flowing air will locally approach the filter element 401 and will travel in at least a generally upstream-downstream direction D of the filter element. u-d The alignment direction is partially away from the filter element 401. This direction will generally be at least approximately the same as the pleat direction D of the pleated filter media 410. p Orthogonal. That is, in the ordinary use of the pleated filter element 401, there may often be little or no airflow along the long axis of the valleys of the pleated medium. Specifically, the pleated filter element 401 differs from arrangements in which fluid flows along the valleys between multiple layers (e.g., stacks or wrappers) of the pleated medium. The pleated filter element 401 is therefore different from, for example, so-called spiral wound filters, which, when supplied, comprise multiple layers of filter media and in which substantial fluid flow can occur along the long axis of the valleys between the layers of the pleated medium.

[0078] Figure 6 A method for manufacturing a pleated bag according to an embodiment of this document is illustrated. Method 600 illustrates an example process for manufacturing and using the filter material as described herein. However, it is clearly contemplated that other suitable methods are also applicable.

[0079] At frame 610, a filter material is obtained. The filter material may be similar to filter media 420 in the embodiments herein. In some embodiments, the filter media may have an effective diameter of about 2µm to 6µm. In some embodiments, the filter media has an effective diameter of less than 5µm, or less than 4µm, or less than 3µm. In some embodiments, the filter media has an effective diameter of greater than 2µm. The filter material may have a fiber solids content of at least about 10% and less than about 18%. The filter media may have a basis weight of at least 50 gsm and less than about 100 gsm. The filter media may have a glystin content of greater than about 150 mg, or even greater than about 200 mg, or even greater than about 250 mg, or even greater than about 300 mg, or even greater than about 350 mg, or even greater than about 400 mg, or even greater than about 450 mg, or even greater than about 500 mg, or even greater than about 550 mg. The filter media may have a glystin content of less than about 1000 mg, or less than about 550 mg, or even less than about 350 mg.

[0080] According to the embodiment described herein, the filter material is a meltblown nonwoven material. Meltblown nonwoven materials exhibit better filtration properties and can better facilitate the charging process.

[0081] At frame 620, the filter medium is charged. Any suitable charging method can be used, selected from, for example, corona charging, water charging, triboelectric charging, etc. In some embodiments, the filter medium may be formed from pre-charged electret fibers; or the filter medium may be formed (e.g., collected as a nonwoven web and combined (if desired) or formed as a membrane) and then post-charged. If desired, the medium may include one or more charging additives, such as any of the additives described in International Patent Publication WO 2016 / 033097, published March 3, 2016 (which is incorporated herein by reference). Other suitable charging mechanisms are contemplated. However, it is explicitly contemplated that the embodiments herein are configured such that the final pleated filter element is free of fluoride compounds.

[0082] In some implementations, when the test methods described in the examples are used, the dielectric sheet experiences a pressure drop of less than about 50 mmH2O at a surface velocity of 13.8 cm / s, or even less than about 40 mmH2O at a surface velocity of 13.8 cm / s, or even less than about 30 mmH2O at a surface velocity of 13.8 cm / s, or even less than about 25 mmH2O at a surface velocity of 13.8 cm / s, or even less than about 20 mmH2O at a surface velocity of 13.8 cm / s, or even less than about 15 mmH2O at a surface velocity of 13.8 cm / s, or even less than about 10 mmH2O at a surface velocity of 13.8 cm / s. In some implementations, the pleated medium experiences a pressure drop of less than about 9 mmH2O at a surface velocity of 13.8 cm / s, or even less than about 8 mmH2O at a surface velocity of 13.8 cm / s, or even less than about 7 mmH2O at a surface velocity of 13.8 cm / s, or even less than about 6 mmH2O at a surface velocity of 13.8 cm / s, or even less than about 5 mmH2O at a surface velocity of 13.8 cm / s, or even less than about 4 mmH2O at a surface velocity of 13.8 cm / s, or even less than about 3 mmH2O at a surface velocity of 13.8 cm / s.

[0083] At frame 630, the monolithic filter media is pleated to form a self-supporting pleated filter material. The pleated filter media is self-supporting but contains no added reinforcing elements or additives, such as adhesives. In contrast to softer, rounded pleats in an "S" shape, the pleats in the pleated filter media are sharp pleats exhibiting a "zigzag" shape. As described above... Figures 3A to 3B The sharp pleats reduce blockage in the air channels created by the pleats.

[0084] The pleated filter media can exhibit percentage permeability of less than about 1.0, 0.1, 0.05, or even less than about 0.01 at a face velocity of 13.8 cm / s (i.e., initial percentage permeability of DOP, measured according to the process disclosed in the working examples). In some embodiments, the pleated filter media exhibits even less than about 0.001% percentage permeability when measured according to the procedure disclosed in the working examples.

[0085] The pleats in the pleated filter media manufactured according to the embodiments herein may have a pleat height of at least about 0.25 inches, or at least about 0.5 inches, or at least about 1.0 inch, or at least about 1.5 inches. The pleat density of the pleated filter media is at least about 7 pleats / inch, at least about 8 pleats / inch, at least about 9 pleats / inch, at least about 10 pleats / inch, at least about 11 pleats / inch, or even at least about 12 pleats / inch, or even at least about 13 pleats / inch, or even at least 14 pleats / inch, or even at least 15 pleats / inch.

[0086] Pleating can be achieved using appropriate pleating processes and various folding line forming processes.

[0087] At frame 640, a pleated package is assembled. The pleated package may include a housing configured to be received by a reusable respirator (RR) or PAPR unit. For example, the reusable housing may include suitable coupling features for attachment to the RR or PAPR unit. The coupling features should be designed to significantly prevent ambient air from entering the RR or PAPR unit without passing through the pleated element. For example, the coupling features may include gaskets or a compliant material. In embodiments herein, the coupling features are removable such that when the pleated package reaches the end of its service life, it can be removed from the RR or PAPR, and a new pleated package can be attached in place. In some embodiments, the housing of the pleated package may be at least partially recyclable.

[0088] The pleated bag is assembled by placing pleated material inside the housing. In some embodiments described herein, the pleated material is adhered to the surface of the housing using an adhesive. However, it is explicitly contemplated that the adhesive used to adhere the pleated material inside the housing will not meaningfully contribute to the self-support of the pleated material.

[0089] The pleated pouches formed according to the embodiments described herein are configured to meet various regulatory standards, including, for example, NIOSH standards such as N95, N99, N100, High Efficiency (HE), R95, P95, P99, and / or P100, when properly used with RR or PAPR fitted for the wearer. The embodiments described herein meet oil-resistant aerosol standards while being free of fluorinated compounds or fluorinated treatments.

[0090] Edge baffle

[0091] In some embodiments, the filter element 401 has one or more adhesive edge baffles (in) Figures 4A to 4D(Example shown as edge baffle 440). The adhesive edge baffles may be positioned near the corrugated edge (404 or 404') of the pleated filter media. Each baffle may be formed of a hardened adhesive. In many embodiments, the adhesive may be provided as a liquid near the edge of the filter media, which is applied as elongated beads extending along the longitudinal direction of the media. The adhesive beads may be applied simultaneously to both the upstream and downstream main surfaces of the media; or, the adhesive beads may be applied to one main surface and then to the other main surface. After the adhesive beads have been applied to both main surfaces, the media may then be compressed along the longitudinal direction of the media (while the adhesive is still at least in a semi-liquid state) into the final pleated configuration (which exhibits pleat spacing, pleat height, etc., which are required when using filter element 401). This will result in the adhesive at least substantially filling each pleat valley located near the corrugated edge of the pleated filter media. The adhesive may then be hardened while the filter media remains in this pleated configuration.

[0092] The hardened adhesive thus forms a baffle 440. In at least some embodiments, the pleated filter media 410 includes a first edge baffle 440 located at one corrugated edge 404 of the pleated filter media and a second edge baffle 440' located at the other corrugated edge 404', as shown below. Figures 4A to 4D As shown (in) Figure 4B (Only a single edge baffle 440 is visible in the side view). It should be understood that the hardened adhesive portions in the upstream fold 422 and the downstream fold 432 work together to provide baffle 440, even though those adhesive portions in the upstream and downstream folds are separated from each other by the thickness of the filter medium and may therefore never physically contact each other. That is, the hardened upstream adhesive portions and the hardened downstream adhesive portions together form baffle 440.

[0093] Baffles 440 and 440' (and optional internal baffles) provide structural rigidity to the pleated air filter media, which makes the resulting filter element mechanically more robust, eliminating the need for, for example, housing materials that might add undesirable weight and / or complexity. It should also be noted that the presence of such adhesive baffles allows for tight pleating patterns. That is, if a very tight pleated pattern is used, the adhesive baffles can act as spacers such that adjacent walls of the pleats do not completely press against each other, so that they are so closely spaced (e.g., in contact with each other) that they adversely obstruct airflow through the pleat valleys.

[0094] In various embodiments, each adhesive edge baffle may be located at a position approximately flush with the end of the corrugated edge to a position where it is recessed inward from the end of the corrugated edge (measured from the centerline of the baffle) by no more than approximately 0.1 mm, 0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm, 1.0 mm, 2.0 mm, 3.0 mm, or 4.0 mm. As a specific example, such as... Figure 4A The exemplary adhesive edge baffles 40 and 40' shown may be positioned, for example, 1 mm to 2 mm inward from the terminal side of the corrugated edges 404 and 404', and no part of each adhesive edge baffle extends outward beyond the terminal of the corrugated edge to which it is adjacent.

[0095] In some embodiments, an edge baffle made of a hardened adhesive may at least substantially or substantially fill the upstream and downstream pleats, thereby at least substantially closing the pleats to prevent airflow through them. In this case, the edge baffle may act as an edge seal that at least substantially or substantially prevents air (or any other flowing gas or gas mixture) from flowing laterally outward beyond the corrugated edges of the pleated filter media and thus at least partially bypassing the filter media. (In particular cases, the edge baffle acting as an edge seal may be verified, for example, by mounting the filter element in a housing as described later herein; if the performance of the filter element is substantially unaffected by any external seals or gaskets applied to the filter element, this would indicate that the edge baffle is performing as an edge seal in the manner described herein.) It should be understood that the use of a hardened adhesive edge baffle 440 acting as an edge seal in this manner may, for example, eliminate the need to cover the corrugated edges of the pleated filter element with housing portions or gaskets, or to seal the corrugated edges of the pleated filter element by impregnating the edges in a sealing material. Or, at the very least, the extent to which such measures might be necessary, and thus allow for a reduction in the complexity and cost of filter element 401.

[0096] If needed, it can be done as follows Figure 4A One or more additional internal baffles 442 are laterally disposed between the first adhesive edge baffle 440 and the second adhesive edge baffle 440', as shown in the exemplary embodiment. While not necessarily required for any sealing function, such additional internal adhesive baffles can provide mechanical rigidity to the pleated filter element and can also help maintain the pleats of the filter media in, for example, a tightly pleated configuration (e.g., with...). Figure 4D (The example illustrates a construction of the type shown). If desired, adhesive baffles may be spaced at least substantially uniformly across the lateral extent of the pleated filter media (e.g. Figure 4A(As in the exemplary implementation). Alternatively, this spacing can be varied as needed. Any number of internal baffles can be present (e.g., one, two, three, four, or more). Figure 4A Two such internal baffles are depicted in the text.

[0097] The edge baffle is discussed in more detail in U.S. Patent 11,452,891 to Sebastian et al., issued on September 27, 2022, the text of which is incorporated herein by reference.

[0098] A filter element is proposed, comprising a pleated filter media including an upstream main surface and a downstream main surface, and including multiple pleats having a pleating direction and having multiple upstream pleat tips and upstream valleys, as well as multiple downstream pleat tips and downstream pleat valleys. The pleated filter media comprises a single-layer nonwoven web comprising meltblown polymer fibers having a fiber solids content of at least 10% and an effective fiber diameter of at least 2µm. The pleated filter media is self-supporting.

[0099] The filter element can be configured such that a single sheet of nonwoven fabric has a basis weight of at least about 50 g / m². The filter element can be configured such that a single sheet of nonwoven fabric has a basis weight of at least about 70 g / m². The filter element can be configured such that a single sheet of nonwoven fabric has a basis weight of less than about 120 g / m². The filter element can be configured such that a single sheet of nonwoven fabric has a basis weight of less than about 100 g / m².

[0100] The filter element can be implemented such that a single piece of nonwoven fabric has a thickness of at least about 0.3 mm. The filter element can be implemented such that a single piece of nonwoven fabric has a thickness of less than about 2 mm. The filter element can be implemented such that a single piece of nonwoven fabric has a thickness of less than about 1.7 mm. The filter element can be implemented such that a single piece of nonwoven fabric has a thickness of less than about 1.5 mm. The filter element can be implemented such that a single piece of nonwoven fabric has a thickness of less than about 0.5 mm.

[0101] The filter element can be implemented such that the effective fiber diameter is at least 2.5µm.

[0102] The filter element can be implemented such that the effective fiber diameter is at least 3µm.

[0103] The filter element can be implemented such that the pleats are ultrasonically etched pleats.

[0104] The filter element can be implemented such that the pleats are rotational grooves or thermal grooves.

[0105] The filter element can be configured to give a single piece of nonwoven fabric a glyph strength of at least about 150 mg. The filter element can be configured to give a single piece of nonwoven fabric a glyph strength of at least about 200 mg. The filter element can be configured to give a single piece of nonwoven fabric a glyph strength of at least about 300 mg. The filter element can be configured to give a single piece of nonwoven fabric a glyph strength of at least about 400 mg. The filter element can be configured to give a single piece of nonwoven fabric a glyph strength of less than about 1000 mg. The filter element can be configured to give a single piece of nonwoven fabric a glyph strength of less than about 550 mg. The filter element can be configured to give a single piece of nonwoven fabric a glyph strength of less than about 350 mg.

[0106] Filter elements can be configured such that the pleated filter media has a pleat density of at least about 7 pleats / inch. Filter elements can be configured such that the pleated filter media has a pleat density of at least about 10 pleats / inch. Filter elements can be configured such that the pleated filter media has a pleat density of at least about 15 pleats / inch. Filter elements can be configured such that the pleated filter media has a pleat density of less than about 15 pleats / inch.

[0107] Filter elements can be configured such that the pleated filter media has a pleat height of less than 1.5 inches. Filter elements can be configured such that the pleated filter media has a pleat height of less than 1.0 inch. Filter elements can be configured such that the pleated filter media has a pleat height of less than 0.5 inches. Filter elements can be configured such that the pleated filter media has a pleat height of at least 0.25 inches.

[0108] The filter element can be implemented to make a single piece of nonwoven web exhibit a quasi-permanent charge.

[0109] The filter element can be implemented such that a single nonwoven web includes electret fibers.

[0110] The filter element can be configured such that the pressure drop across the pleated filter medium at an airflow rate of 85 LPM is less than approximately 50 mmH2O. The filter element can be configured such that the pressure drop across the pleated filter medium at an airflow rate of 85 LPM is less than approximately 40 mmH2O. The filter element can be configured such that the pressure drop across the pleated filter medium at an airflow rate of 85 LPM is less than approximately 30 mmH2O. The filter element can be configured such that the pressure drop across the pleated filter medium at an airflow rate of 85 LPM is less than approximately 20 mmH2O. The filter element can be configured such that the pressure drop across the pleated filter medium at an airflow rate of 85 LPM is less than or equal to approximately 15 mmH2O. The filter element can be configured such that the pressure drop across the pleated filter medium at an airflow rate of 85 LPM is less than or equal to approximately 12 mmH2O. The filter element can be configured such that the pressure drop across the pleated filter medium at an airflow rate of 85 LPM is less than or equal to approximately 10 mmH2O. The filter element can be configured such that the pressure drop across the pleated filter medium is less than or equal to about 8 mmH2O at an airflow rate of 85 LPM. The filter element can be configured such that the pressure drop across the pleated filter medium is less than or equal to about 5 mmH2O at an airflow rate of 85 LPM. The filter element can be configured such that the pressure drop across the pleated filter medium is less than or equal to about 3 mmH2O at an airflow rate of 85 LPM.

[0111] The filter element can be configured such that the percentage permeability (DOP) of the pleated filter media at an airflow rate of 85 LPM is less than 1%. The filter element can be configured such that the percentage permeability (DOP) of the pleated filter media at an airflow rate of 85 LPM is less than 0.5%. The filter element can be configured such that the percentage permeability (DOP) of the pleated filter media at an airflow rate of 85 LPM is less than 0.1%. The filter element can be configured such that the percentage permeability (DOP) of the pleated filter media at an airflow rate of 85 LPM is less than 0.01%. The filter element can be configured such that the percentage permeability (DOP) of the pleated filter media at an airflow rate of 85 LPM is less than 0.001%.

[0112] The filter element can be implemented to ensure that the single-piece nonwoven web is free of fluorinated compounds.

[0113] The filter element can be implemented such that the pleated filter media is free of lamination adhesive.

[0114] The filter element can be made so that the pleated filter media does not contain glass fibers.

[0115] The filter element can be implemented such that the pleated filter media exhibits integral mechanical properties across the entire upstream main surface.

[0116] The filter element can be implemented such that the pleated tips are sharp tips.

[0117] The filter element can be implemented such that the width of the pleats is greater than twice the radius of curvature of the pleat tip.

[0118] The filter element can be implemented in such a zigzag pattern that the tips of the pleats form a zigzag pattern.

[0119] The filter element can be implemented such that the meltblown polymer fiber comprises polypropylene.

[0120] The filter element can be implemented such that most of the upstream and downstream folds are at least partially unclosed.

[0121] A filter cartridge for a reusable breathing apparatus is proposed, comprising a housing, a monolithic self-supporting corrugated media, and an inner surface of the housing bonded to the corrugated media. The housing includes a connecting element configured for removable attachment to the reusable breathing apparatus. At least one main surface has a permeable area. The housing is configured such that substantially all ambient airflow is forced through the permeable area. The monolithic self-supporting corrugated media exhibits a quasi-permanent charge and comprises a meltblown polymer fiber web having a fiber solids content of at least 9% and an effective fiber diameter between 2µm and 8µm. The monolithic self-supporting corrugated media is an unlaminated sheet without a reinforcing layer. The bonded connection does not provide significant reinforcement to the corrugated media sheet.

[0122] The pleated bag can be implemented such that the reusable respirator device is a half-mask respirator, and wherein the connecting element is configured to be removably connected to the half-mask respirator.

[0123] The pleated bag can be implemented such that the reusable respirator device is a full-body respirator, and wherein the connecting element is configured to be removably connected to the full-body respirator.

[0124] The pleated bag can be implemented such that the reusable respirator device is a powered air-purifying respirator, and wherein the connecting element is configured to be removably connected to the powered air-purifying respirator.

[0125] The pleated package can be configured such that a single sheet of self-supporting pleated media has a basis weight of at least about 50 g / m². The pleated package can be configured such that a single sheet of self-supporting pleated media has a basis weight of at least about 70 g / m². The pleated package can be configured such that a single sheet of self-supporting pleated media has a basis weight of less than about 120 g / m².

[0126] The pleated package can be implemented such that a single self-supporting pleated medium has a thickness of at least about 0.3 mm. The pleated package can also be implemented such that a single self-supporting pleated medium has a thickness of less than about 1.2 mm.

[0127] The pleated package can be configured to provide a single sheet of self-supporting pleated media with a Glucosamine stiffness of at least 150 mg. The pleated package can be configured to provide a single sheet of self-supporting pleated media with a Glucosamine stiffness of at least 200 mg. The pleated package can be configured to provide a single sheet of self-supporting pleated media with a Glucosamine stiffness of at least 300 mg. The pleated package can be configured to provide a single sheet of self-supporting pleated media with a Glucosamine stiffness of at least 550 mg. The pleated package can be configured to provide a single sheet of self-supporting pleated media with a Glucosamine stiffness of less than about 1000 mg. The pleated package can be configured to provide a single sheet of self-supporting pleated media with a Glucosamine stiffness of less than about 550 mg. The pleated package can be configured to provide a single sheet of self-supporting pleated media with a Glucosamine stiffness of less than about 350 mg.

[0128] The pleated package can be implemented such that the self-supporting pleated medium has a pleat density of at least about 7 pleats / inch. The pleated package can be implemented such that the self-supporting pleated medium has a pleat density of at least about 10 pleats / inch. The pleated package can be implemented such that the self-supporting pleated medium has a pleat density of less than or equal to about 15 pleats / inch.

[0129] The pleated package can be configured such that the self-supporting pleated medium has a pleat height of less than 1.5 inches. The pleated package can be configured such that the self-supporting pleated medium has a pleat height of less than 1.0 inch. The pleated package can be configured such that the self-supporting pleated medium has a pleat height of less than 0.5 inches. The pleated package can be configured such that the self-supporting pleated medium has a pleat height of at least 0.25 inches. The pleated package can be configured such that the meltblown polymer fibers include electret fibers. The pleated package can be configured such that the pressure drop across the self-supporting pleated medium is less than about 50 mmH2O at an airflow rate of 85 LPM. The pleated package can be configured such that the pressure drop across the self-supporting pleated medium is less than about 40 mmH2O at an airflow rate of 85 LPM. The pleated package can be configured such that the pressure drop across the self-supporting pleated medium is less than about 30 mmH2O at an airflow rate of 85 LPM. The pleated bag can be implemented such that the pressure drop across the self-supporting pleated medium is less than about 20 mmH2O at an airflow rate of 85 LPM. The pleated bag can be implemented such that the pressure drop across the self-supporting pleated medium is less than about 15 mmH2O at an airflow rate of 85 LPM. The pleated bag can be implemented such that the pressure drop across the self-supporting pleated medium is less than about 12 mmH2O at an airflow rate of 85 LPM. The pleated bag can be implemented such that the pressure drop across the self-supporting pleated medium is less than about 10 mmH2O at an airflow rate of 85 LPM. The pleated bag can be implemented such that the pressure drop across the self-supporting pleated medium is less than about 8 mmH2O at an airflow rate of 85 LPM. The pleated bag can be implemented such that the pressure drop across the self-supporting pleated medium is less than about 5 mmH2O at an airflow rate of 85 LPM.

[0130] The pleated package can be implemented such that the percentage permeability (DOP) of the self-supporting pleated medium at an airflow rate of 85 LPM is less than 1%. The pleated package can also be implemented such that the percentage permeability (DOP) of the self-supporting pleated medium at an airflow rate of 85 LPM is less than 0.5%.

[0131] The pleated pack can be configured such that the percentage permeability (DOP) of the self-supporting pleated media at an airflow rate of 85 LPM is less than 0.1%. The pleated pack can be configured such that the percentage permeability (DOP) of the pleated filter media at an airflow rate of 85 LPM is less than 0.01%. The pleated pack can be configured such that the percentage permeability (DOP) of the pleated filter media at an airflow rate of 85 LPM is less than 0.001%.

[0132] The pleated package can be implemented such that the self-supporting pleated medium is free of fluoride compounds.

[0133] The pleated package can be implemented such that the self-supporting pleated medium is free of glass fiber.

[0134] The pleated package can be implemented such that the self-supporting pleated medium exhibits uniform mechanical properties across the entire upstream master surface.

[0135] A pleated bag can be made such that the tips of the pleats are sharp points.

[0136] A pleated bag can be made so that the tips of the pleats form a zigzag pattern.

[0137] The pleated package can be implemented such that the meltblown polymer fiber comprises polypropylene.

[0138] A folded package can be implemented such that most of the upstream and downstream fold valleys are at least partially unclosed.

[0139] A respirator is proposed, comprising a mask body and a filter element housing fluidly connected to the mask body. The filter element housing includes: a coupling element configured to mechanically connect to the mask body; and a monolithic pleated filter media having a basis weight of at least 60 g / m², comprising meltblown polymer fibers. The filter element housing accommodates the monolithic pleated filter media. The pleated filter media is self-supporting, such that the monolithic pleated media does not contain a reinforcing layer, and wherein the monolithic pleated filter media exhibits a quasi-permanent charge.

[0140] The respirator can be implemented such that the main body of the mask is fully equipped.

[0141] The respirator can be implemented such that the main body of the mask is a half-mask.

[0142] The respirator may also include a remote unit comprising a filter housing, and the remote unit is a power unit including a fan and a supply tube that fluidly connects the remote unit to the mask body, thereby enabling filtered air to be delivered from the remote unit to the mask body.

[0143] The respirator can be implemented such that a single piece of pleated filter media adheres to the inner surface of the filter element housing.

[0144] The respirator can be configured such that the pleated filter media has a basis weight of at least 50 g / m². The respirator can be configured such that the pleated media has a basis weight of at least about 70 g / m². The respirator can be configured such that the pleated media has a basis weight of less than about 120 g / m².

[0145] The respirator can be configured such that the pleated medium has a thickness of at least about 0.3 mm. The respirator can be configured such that the pleated medium has a thickness of at least about 0.5 mm. The respirator can be configured such that the meltblown polymer fibers have an effective fiber diameter of at least about 2 µm. The respirator can be configured such that the meltblown polymer fibers have an effective diameter of less than about 12 µm.

[0146] The respirator can be configured such that the meltblown polymer fiber has a fiber solids content of at least about 9%. The respirator can be configured such that the meltblown polymer fiber has a fiber solids content of at least about 12%. The respirator can be configured such that the meltblown polymer fiber has a fiber solids content of at least about 14%. The respirator can be configured such that the meltblown polymer fiber has a fiber solids content of at least about 16%. The respirator can be configured such that the meltblown polymer fiber has a fiber solids content of less than or equal to about 18%.

[0147] The respirator can be configured such that the pleated medium has a glycol content of at least 150 mg. The respirator can be configured such that the pleated medium has a glycol content of at least 200 mg. The respirator can be configured such that the pleated medium has a glycol content of at least 300 mg. The respirator can be configured such that the pleated medium has a glycol content of at least 550 mg. The respirator can be configured such that the pleated medium has a glycol content of less than about 550 mg. The respirator can be configured such that the pleated medium has a glycol content of less than about 1000 mg. The respirator can be configured such that the pleated medium has a glycol content of less than about 350 mg.

[0148] The respirator can be configured such that the pleated filter media has a pleat height of less than 1.5 inches. The respirator can be configured such that the pleated filter media has a pleat height of less than 0.5 inches. The respirator can be configured such that the pleated filter media has a pleat height of less than 1.0 inch. The respirator can be configured such that the pleated filter media has a pleat height of less than 0.5 inches.

[0149] The respirator can be configured such that the pleated filter media has a pleat density of at least about 7 pleats / inch. The respirator can be configured such that the pleated filter media has a pleat density of at least about 10 pleats / inch. The respirator can be configured such that the pleated filter media has a pleat density of less than or equal to about 15 pleats / inch.

[0150] The respirator can be implemented such that the meltblown polymer fibers include electret fibers.

[0151] The respirator can be implemented such that the pressure drop over the pleated medium is less than about 50 mmH2O at an air flow rate of 85 LPM. The respirator can also be implemented such that the pressure drop over the pleated medium is less than about 40 mmH2O at an air flow rate of 85 LPM.

[0152] The respirator can be implemented such that the pressure drop over the pleated medium at an airflow rate of 85 LPM is less than about 30 mmH2O. The respirator can be implemented such that the pressure drop over the pleated medium at an airflow rate of 85 LPM is less than about 20 mmH2O. The respirator can be implemented such that the pressure drop over the pleated medium at an airflow rate of 85 LPM is less than about 15 mmH2O. The respirator can be implemented such that the pressure drop over the pleated medium at an airflow rate of 85 LPM is less than about 12 mmH2O. The respirator can be implemented such that the pressure drop over the pleated medium at an airflow rate of 85 LPM is less than about 10 mmH2O. The respirator can be implemented such that the pressure drop over the pleated medium at an airflow rate of 85 LPM is less than about 8 mmH2O. The respirator can be implemented such that the pressure drop over the pleated medium at an airflow rate of 85 LPM is less than about 5 mmH2O. The respirator can be implemented such that the pressure drop over the pleated medium at an airflow rate of 85 LPM is greater than about 3 mmH2O.

[0153] The respirator can be configured such that the percentage permeability (DOP) of the corrugated media at an airflow rate of 85 LPM is less than 1%. The respirator can be configured such that the percentage permeability (DOP) of the corrugated media at an airflow rate of 85 LPM is less than 0.5%. The respirator can be configured such that the percentage permeability (DOP) of the corrugated media at an airflow rate of 85 LPM is less than 0.1%. The respirator can be configured such that the percentage permeability (DOP) of the corrugated filter media at an airflow rate of 85 LPM is less than 0.01%. The respirator can be configured such that the percentage permeability (DOP) of the corrugated filter media at an airflow rate of 85 LPM is less than 0.001%. The respirator can be configured such that the corrugated media is free of fluorinated compounds.

[0154] The respirator can be made so that the pleated medium does not contain glass fibers.

[0155] The respirator can be implemented such that the pleated medium exhibits uniform mechanical properties across the entire upstream main surface.

[0156] The respirator can be implemented such that the pleated medium includes multiple sharp pleated tips.

[0157] The respirator can be implemented in a zigzag pattern formed by multiple sharp, pleated tips.

[0158] The respirator can be implemented such that the meltblown polymer fiber comprises polypropylene.

[0159] A filter medium for use in a respiratory protective device, the filter medium comprising: A nonwoven web having a thickness between approximately 0.3 mm and 2.0 mm, comprising multiple polymer meltblown fibers. The nonwoven webs exhibited a glystin of at least 150 mg, and The filter media exhibits a quasi-permanent charge.

[0160] The filter medium can be configured such that multiple polymer meltblown fibers exhibit an effective fiber diameter between approximately 2 µm and approximately 8 µm.

[0161] The filter medium can be configured such that the plurality of meltblown fibers have a fiber solids content of at least about 9%. The filter medium can be configured such that the plurality of meltblown fibers have a fiber solids content of at least about 12%. The filter medium can be configured such that the plurality of meltblown fibers have a fiber solids content of at least about 14%. The filter medium can be configured such that the plurality of meltblown fibers have a fiber solids content of at least about 16%. The filter medium can be configured such that the plurality of meltblown fibers have a fiber solids content of less than about 20%.

[0162] The filter media can be configured to give the nonwoven web a glyphic stiffness of at least about 200 mg. The filter media can be configured to give the nonwoven web a glyphic stiffness of at least about 300 mg. The filter media can be configured to give the nonwoven web a glyphic stiffness of at least about 400 mg. The filter media can be configured to give the nonwoven web a glyphic stiffness of at least about 500 mg. The filter media can be configured to give the nonwoven web a glyphic stiffness of less than about 1000 mg.

[0163] The filter media can be configured to give the nonwoven web a basis weight of at least about 50 g / s². The filter media can be configured to give the nonwoven web a basis weight of at least about 70 g / s². The filter media can be configured to give the nonwoven web a basis weight of at least about 80 g / s². The filter media can be configured to give the nonwoven web a basis weight of at least about 90 g / s². The filter media can be configured to give the nonwoven web a basis weight of less than about 120 g / s².

[0164] The filter medium can be made so that the self-supporting pleated medium is free of fluoride compounds.

[0165] The filter medium can be made to resist oily aerosols at least partially.

[0166] The filter medium can be made to be substantially oil-resistant to oily aerosols.

[0167] The filter medium can be made so that the nonwoven web is free of adhesive.

[0168] The filter medium can be made so that the nonwoven web is free of glass fibers.

[0169] The filter medium can be made to give the nonwoven web an overall mechanical property across the entire upstream master surface.

[0170] The filter medium can be configured such that the meltblown polymer fibers include electret fibers.

[0171] A respirator is proposed, comprising a mask body and a filter element housing fluidly connected to the mask body. The filter element housing includes a coupling element configured to mechanically connect to the mask body; and a monolithic pleated filter media. The pleated filter media comprises a nonwoven sheet having a basis weight of at least 60 g / m², a solids content of at least 10%, and a glyph stiffness of at least 150 mg prior to pleating. The monolithic pleated filter media has a pleat density of at least about 9 pleats / inch. The filter media comprises meltblown polymer fibers, wherein the filter element housing contains the monolithic pleated filter media. The monolithic pleated filter media is self-supporting, such that the filter element housing has no reinforcing structure or support layer of any kind. The monolithic pleated filter media exhibits a quasi-permanent charge.

[0172] The respirator can be configured such that the meltblown polymer fibers have an effective diameter of at least about 2 µm. The respirator can be configured such that the meltblown polymer fibers have an effective diameter of at least about 3 µm. The respirator can be configured such that the meltblown polymer fibers have an effective diameter of at least about 4 µm. The respirator can be configured such that the meltblown polymer fibers have an effective diameter of less than about 7 µm. The respirator can be configured such that the meltblown polymer fibers have an effective diameter of less than about 5 µm.

[0173] The respirator can be implemented such that the pressure drop on the unpleated filter media sheet is less than 25 mm H2O.

[0174] The respirator can be implemented such that the basis weight of the nonwoven media sheet is at least about 80 gsm. The respirator can also be implemented such that the basis weight of the nonwoven media sheet is less than about 115 gsm.

[0175] The respirator can be implemented such that the nonwoven media sheet has a solids content of less than about 16%.

[0176] The respirator can be implemented such that the nonwoven media sheet has a thickness of at least 0.2 inches.

[0177] The respirator can be implemented such that the nonwoven media sheet has a thickness of less than 0.5 inches.

[0178] The respirator can be designed to have a glystin of less than 500 mg for the nonwoven filter media sheet.

[0179] The respirator can be designed to achieve a percentage permeability (DOP) of less than 0.01% for the nonwoven filter media sheet at an airflow rate of 85 LPM.

[0180] Example

[0181] Testing procedures

[0182] Effective fiber diameter

[0183] The effective fiber diameter (EFD) of the web was calculated according to the method proposed in Davies, CN, “The Separation of Airborne Dust and Particles,” Institution of Mechanical Engineers (London, Proceedings 1B, 1952). Unless otherwise stated, for flat filter media, the test was conducted at a surface velocity of 13.8 cm / s.

[0184] Grittium

[0185] Gurley stiffness was measured using a Gurley stiffness tester, model 4171E (digital), purchased from Gurley Precision Instruments, Troy, NY. Stiffness was measured according to the procedures provided in the tester's instruction manual. For each material, three spaced-apart individual physical samples were tested. Each sample was a flat web (unpleated) sample, cut (e.g., from a roll) to a sample size of 2 inches × 1.5 inches. If the sample exhibited a recognizable machine orientation (co-direction), it was cut such that the long (test) dimension was aligned with the machine orientation of the sample. During testing, the sample was bent in the co-direction. Each individual physical sample was tested twice, cycling back and forth from the left and right sides of the sample. The results were averaged and reported in milligrams of force (Gurley units).

[0186] Permeability, pressure drop and quality factor

[0187] The percentage permeability, pressure drop, filtration quality factor (QF), and related parameters of the filter media samples were obtained using test aerosols containing DOP (dioctyl phthalate) droplets or NaCl (sodium chloride) solid particles in a manner substantially similar to that disclosed in PCT International Publication WO 2015 / 199972, published on December 30, 2015, and PCT Publication WO 2015 / 024891, published on March 12, 2015, both of which are incorporated herein by reference. The Automated Filtration Tester AFT Model 8130 (TSI, Inc., St. Paul MN, Minnesota) can be used with test aerosols containing DOP droplets or NaCl particles, wherein the mass median diameter is in the range of approximately 0.3 µm (e.g., the mass median diameter of DOP is approximately 0.26 µm, and the mass median diameter of NaCl is approximately 0.33 µm). In the following embodiments, unless otherwise specified, the test aerosol is delivered at a flow rate of 85 L / min (LPM) to provide a surface velocity of 13.8 cm / s. Unless otherwise stated, the test is performed on a flat web.

[0188] Particle concentrations are measured at the sample inlet and outlet to obtain the percentage permeability of particles through the filter web, and the pressure drop through the filter web is monitored using a general-type transducer, such as that purchased from MKS Instruments, Andover, MA, Massachusetts. The following equation can be used: Equation 2 To calculate the quality factor (QF).

[0189] Parameters that can be measured or calculated through such testing procedures include initial percentage permeability, initial pressure drop, and initial quality factor (QF). Initial parameters are obtained after initial exposure of the filter media sample to the test aerosol, as will be well understood by a person skilled in the art. Unless otherwise specified, all percentage permeability and pressure drop values, ranges, etc., present in this document (including the specification and claims) will be understood as initial parameters using DOP. All these values ​​will be interpreted at a surface velocity of 13.8 cm / s.

[0190] Load testing can be performed by continuously testing the filter with aerosols over a period of time while simultaneously monitoring permeability and pressure drop. Testing can be stopped after a specific particulate load is reached or after a clear maximum permeability value is observed, and the final percentage permeability, final pressure drop, and / or final quality factor at the end of the load test can be recorded. All particulate permeability results are reported as percentage permeability (e.g., a reported value of 80 means 80%; a reported value of 0.1 means 0.1%). Filtration efficiency (e.g., initial or final) is also available, which is 100 minus the particulate permeability, and is also reported as a percentage.

[0191] Representative working examples

[0192] Material

[0193] Examples of filter media prepared from polypropylene meltblown nonwoven webs with charged electret portions are presented, and the resulting properties are listed in Table 1, which also lists the pressure drop, percentage permeability, and glystiffness for each example. Filter media EX-9 and EX-10 were calendered after formation.

[0194]

[0195] Pleats

[0196] The media rolls, already cut to approximately 3 inches (7.5 cm) in lateral width, have fold lines formed across the width of the media using a rotary scoring device. Alternatively, the fold lines are formed using a servo-knife folding machine manufactured by Roth Composite Machinery. The fold lines are spaced along the longitudinal (coaxial) length of the media to provide the fold height as described in the embodiments (after the media is compressed into a folded configuration).

[0197] The medium with folded lines, when in a flat configuration, has four liquid hot-melt adhesive beads (trade name PF-3165 from Truxes Company) applied to the main surface of the medium. The four upstream beads (passing through nozzles of the grate as the flat medium moves across it) are applied as elongated strips spaced apart across the width of the medium and extending along its longitudinal length. Of these four beads, the first and second are edge beads, applied at a position no more than approximately 2-3 mm laterally inward from the first and second edges of the medium. The third and fourth beads are inner beads, spaced generally similarly and equally across the width of the medium between the two edge beads (thus, the lateral spacing between each pair of beads is in the range of approximately 22-28 mm). Simultaneously, similar beads are applied to the (opposite) main surface of the nonwoven web (which will ultimately provide the downstream surface of the folded medium). Within a lateral distance of approximately 2 mm or less, each downstream bead is aligned with its corresponding upstream bead.

[0198] While the adhesive beads are still in liquid form, the scored medium is compressed (during which the medium folds along the scored lines) to its final folded configuration with fold spacing. During this process, as folds form, the liquid adhesive penetrates into the fold valleys and at least substantially fills them, protruding outwards at the fold tips by an estimated (on average) approximately 0.5–1 mm beyond the fold tips. During this process, the adhesive remains sufficiently tacky on the bead surface so that the two parts of the adhesive bead can bond sufficiently to each other if they converge in the fold valleys during the folding operation. The adhesive is then hardened so that each pair of aligned upstream and downstream beads together form a baffle made of the hardened adhesive.

[0199] The pleated media with a hardened adhesive baffle is then cut to a certain length to form pleated filter elements, thereby fitting the dimensions of filter cartridges 1 and 2. Each pleated filter element is installed into the filter element housing of filter cartridges 1 and 2. Since the filter element housing of filter cartridge 2 includes an arc-shaped receiver for receiving the arc-shaped filter element, the pleated filter element of filter cartridge 2 is conformed (along a conforming axis substantially parallel to the longitudinal axis of the pleated filter element) into an arc shape, wherein the radius of curvature is estimated to be in the range of approximately 30 cm.

[0200] Compared to the receiver, the pleated filter elements of both filter cartridges 1 and 2 are slightly longer (e.g., in the range of 2mm-3mm), causing the non-corrugated ends of the filter elements to remain within the receiver under slight compression. Adhesive beads (wet-curing polyurethane adhesive, trade name SCOTCH-WELD) are then applied. ™TE040 (obtained from 3M) is applied to the downstream periphery of the filter element (overlapping onto the adjacent surface of the housing) to securely hold the filter element in place. It should be noted that in at least some samples, the edge beads appear to at least substantially close the corrugated edges of the pleated filter media. Therefore, it is believed that satisfactory filtration performance can be achieved by using downstream adhesive beads solely for securing the filter element in place (and sealing the non-corrugated edges of the filter element against the adjacent wall of the receiver of the housing), rather than such downstream adhesive beads required to seal the corrugated edges of the filter element to prevent leakage.

[0201] The performance of the pleated filter element installed in the housing as described above was evaluated.

[0202] The filter media is pleated for insertion into filter cartridge 1, which has a nominal dimension of 1.8 inches across the pleats and 3 inches along the pleats, wherein each embodiment has additional dimensions, pressure drop (PD), and percentage permeability illustrated in Tables 2 and 3.

[0203]

[0204] The filter media is also pleated to be inserted into filter cartridge 2, which has an 8.3-inch diameter. L and 3-inch D p The nominal size, with other sizes and permeabilities illustrated in Table 3.

[0205]

[0206] The above embodiments are provided merely for a clear understanding of the invention and should not be construed as unnecessary limitations. The tests and test results described in the embodiments are intended to be illustrative rather than predictive, and variations in the testing process may yield different results. All quantitative values ​​in the embodiments should be understood as approximations based on generally known tolerances involved in the processes used.

[0207] It will be apparent to those skilled in the art that the specific exemplary elements, structures, features, details, configurations, etc., disclosed herein are modifiable and / or combined in many embodiments. The inventors intend that all such variations and combinations are within the scope of the conceived invention, and not merely those representative designs chosen for illustrative purposes. Therefore, the scope of the invention should not be limited to the specific exemplary structures described herein, but should extend at least to the structures described by the language of the claims and their equivalents. Any element positively referenced as an alternative in this specification may be expressly included in or excluded from the claims in any combination as desired. Any element or combination of elements referenced in this specification in open language (e.g., including and its derivatives) is considered to be additionally referenced in closed language (e.g., consisting of and its derivatives) and in partially closed language (e.g., substantially consisting of and its derivatives). While various theories and possible mechanisms may have been discussed herein, such discussions should in no way be used to limit the subject matter protected by the claims. In the event of any conflict or contradiction between the contents of this written specification and any document mentioned and / or incorporated herein by reference, this written specification shall prevail.

Claims

1. A filter element, comprising: A pleated filter medium, comprising an upstream main surface and a downstream main surface, and comprising multiple pleats, the multiple pleats having a pleat direction and having multiple upstream pleat tips and upstream valleys as well as multiple downstream pleat tips and downstream pleat valleys; The pleated filter media comprises only a single layer of nonwoven web, the nonwoven web comprising meltblown polymer fibers having a fiber solids content of at least 10% and an effective fiber diameter of at least 2µm; and The pleated filter media is self-supporting.

2. The filter element according to claim 1, wherein the single piece of the nonwoven web has a basis weight of at least about 50 grams per square meter.

3. The filter element according to any one of claims 1 to 2, wherein the single piece of the nonwoven web has a thickness of at least about 0.3 mm.

4. The filter element according to any one of claims 1 to 3, wherein the single piece of the nonwoven web has a thickness of less than about 2 mm.

5. The filter element according to any one of claims 1 to 4, wherein the wrinkles are ultrasonically scored wrinkles, rotationally scored wrinkles, or thermally scored wrinkles.

6. The filter element according to any one of claims 1 to 5, wherein the single piece of the nonwoven web has a glystiffness of at least about 150 mg.

7. The filter element according to any one of claims 1 to 6, wherein the pleated filter media has a pleat density of at least about 7 pleats per inch.

8. The filter element according to any one of claims 1 to 7, wherein the pressure drop on the pleated filter medium is less than about 50 mmH2O at an air flow rate of 85 LPM.

9. The filter element according to any one of claims 1 to 8, wherein the percentage permeability (DOP) of the pleated filter media at an airflow rate of 85 LPM is less than 1%.

10. The filter element according to any one of claims 1 to 9, wherein the pleated filter media is free of lamination adhesive.

11. The filter element according to any one of claims 1 to 10, wherein the pleated filter media does not contain glass fibers.

12. The filter element according to any one of claims 1 to 11, wherein the pleated tip is a sharp tip.

13. The filter element according to any one of claims 1 to 12, wherein the meltblown polymer fiber comprises polypropylene.

14. The filter element according to any one of claims 1 to 13, wherein the majority of the upstream and downstream folds are at least partially unclosed.

15. A filter cartridge for a reusable breathing apparatus, the filter cartridge comprising: Housing, the housing comprising: A connecting element configured to be removably connected to the reusable breathing device; At least one main surface, the at least one main surface having a breathable area; and The housing is configured such that substantially all ambient airflow is forced through the ventilated area; A monolithic self-supporting corrugated dielectric, wherein the monolithic self-supporting corrugated dielectric exhibits a quasi-permanent charge, the self-supporting corrugated dielectric comprising: A meltblown polymer fiber web, wherein the meltblown polymer fibers have a fiber solids content of at least 9% and an effective fiber diameter between 2µm and 8µm; and The single-piece self-supporting corrugated medium is an unlaminated sheet without a reinforcing layer; and The corrugated medium is bonded to the inner surface of the housing, wherein the bond does not provide significant reinforcement to the corrugated medium sheet.

16. The filter cartridge of claim 15, wherein the reusable respirator is a half-mask respirator and wherein the connecting element is configured to be removably connected to the half-mask respirator; or wherein the reusable respirator is a full-face respirator and wherein the connecting element is configured to be removably connected to the full-face respirator; or wherein the reusable respirator is a powered air-purifying respirator and wherein the connecting element is configured to be removably connected to the powered air-purifying respirator.

17. The filter cartridge according to any one of claims 15 to 16, wherein the single piece of the self-supporting pleated media has a basis weight of at least about 50 g / m².

18. The filter cartridge according to any one of claims 15 to 17, wherein the single piece of the self-supporting pleated media has a thickness of at least about 0.3 mm.

19. The pleated package according to any one of claims 15 to 18, wherein the monolithic self-supporting pleated medium has a glystiffness of at least 150 mg.

20. The filter cartridge according to any one of claims 15 to 19, wherein the self-supporting pleated media has a pleat density of at least about 7 pleats per inch.

21. The filter cartridge according to any one of claims 15 to 20, wherein the pressure drop over the self-supporting pleated medium is less than about 50 mmH2O at an air flow rate of 85 LPM.

22. The filter cartridge according to any one of claims 15 to 21, wherein the percentage permeability (DOP) of the self-supporting pleated media at an airflow rate of 85 LPM is less than 1%.

23. The filter cartridge according to any one of claims 15 to 22, wherein the self-supporting pleated media is free of glass fiber.

24. The filter cartridge according to any one of claims 15 to 23, wherein the pleated tip is a sharp tip.

25. The filter cartridge according to any one of claims 15 to 24, wherein the majority of the upstream and downstream folds are at least partially unclosed.

26. A respirator, comprising: The main body of the mask; A filter element housing, fluidly connected to the mask body, wherein the filter element housing comprises: A connecting element configured to be mechanically connected to the mask body; A single-piece pleated filter media having a basis weight of at least 60 g / m², the pleated filter media comprising meltblown polymer fibers, wherein the filter element housing houses a single piece of the pleated filter media; and The pleated filter media is self-supporting, such that a single piece of the pleated filter media does not contain a reinforcing layer, and the single piece of the pleated filter media exhibits a quasi-permanent charge.

27. The respirator of claim 26, wherein the mask body is a full-face mask or a half-face mask.

28. The respirator according to any one of claims 26 to 27, further comprising a remote unit including the filter element housing, the remote unit being a power unit including a fan and a supply pipe fluidly connecting the remote unit to the mask body, thereby enabling filtered air to be delivered from the remote unit to the mask body.

29. The respirator according to any one of claims 26 to 28, wherein a single piece of the pleated filter media is adhered to the inner surface of the filter element housing.

30. The respirator according to any one of claims 26 to 29, wherein the pleated filter media has a basis weight of at least 50 g / m².

31. The respirator according to any one of claims 26 to 30, wherein the pleated medium has a thickness of at least about 0.3 mm.

32. The respirator according to any one of claims 26 to 31, wherein the meltblown polymer fiber has an effective fiber diameter of at least about 2 µm and less than about 12 µm.

33. The respirator according to any one of claims 26 to 32, wherein the meltblown polymer fiber has a fiber solids content of at least about 9%.

34. The respirator according to any one of claims 26 to 33, wherein the pleated medium has a grittiness of at least 150 mg.

35. The respirator according to any one of claims 26 to 34, wherein the pleated medium has a grittiness of less than about 1000 mg.

36. The respirator according to any one of claims 26 to 35, wherein the pleated filter media has a pleat density of at least about 7 pleats per inch.

37. The respirator according to any one of claims 26 to 36, wherein the pleated medium is free of glass fiber.

38. The respirator according to any one of claims 26 to 37, wherein the pleated medium exhibits uniform mechanical properties across the entire upstream main surface.

39. The respirator according to any one of claims 26 to 38, wherein the pleated medium comprises a plurality of sharp pleated tips.

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