ANTI-MICROBIAL, ANTI-ALLERGENIC BIO-FUNCTIONAL AIR FILTER MEDIUM AND AIR FILTER ELEMENT

Abstract

A bio-functional air filter medium is provided with a at least one particle filtration layer that retains particles and at least one bio-functional carrier coated with or having embedded therein antimicrobial, anti-viral and anti-allergenic materials. An air filter element having the bio-functional air filter medium is also disclosed. The bio-functional air filter medium is adapted to bind and capture allergens and block metabolism of bacteria, and provide anti-viral activity to effectively inhibit/deactivate viruses, all while filtering air in high flow, low pressure drop residential, HVAC or air purifier applications.

Claims

1. A bio-functional air filter medium for air filtration of rooms or interior spaces in residential structures, office buildings, commercial or retail spaces, comprising: at least one particle filtration layer configured to retain particles; and a bio-functional carrier layer having a substrate comprising spunbond or meltblown fibers and having an air permeability greater than or equal to 3000 l/m.sup.2 s; at least one mesh support layer, wherein the at least one mesh support layer, the at least one particle filtration layer and the bio-functional carrier layer structurally cooperate to define pleats and supportively retain a pleat shape of the pleats against air flow forces; wherein the bio-functional carrier layer further comprises: at least one anti-microbial material which includes an anti-microbial material selected from the group consisting of: pyrithione, a pyrithione derivative, and/or a metal salt, or combinations thereof, wherein the anti-microbial materials exhibit anti-viral activity to effectively inhibit and/or inactivate viruses present in the filtered air; and an anti-allergenic material selected from the group consisting of: catechines, tannin or tannic acid derived from wood, apple extracts or citrus bark, apple extracts or citrus fruit extracts, caffeic acid, gallic acid, tea extract, persimmon juice, ellagic acid, tannic acid, hydroxybenzoic acid compounds consisting of (2,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, 2,4,6-trihydroxybenzoic acid), cyanidin, procyanidin, proanthocyanidins, rutin, quercetin, resveratrol, anti-allergenic enzymes or combinations thereof; wherein the anti-allergenic material binds to and captures allergenic substances in the bio-functional carrier layer so that an allergenic effect is reduced; wherein the anti-allergenic material and the anti-microbial material are applied onto the bio-functional carrier layer as a coating or introduced into the fibers of the bio-functional carrier layer, forming a positive-charged protective shield on the bio-functional carrier layer substrate, such that bacterial cells with their negative charge are attracted and inactivated when contacting the bio-functional carrier layer, blocking cell function and reproduction; wherein the anti-microbial material provides anti-viral activity to deactivate viruses and is also configured to block metabolism of bacteria and mold in order to avoid growth of these on the filter surface or decomposition of the anti-allergenic material in the bio-functional carrier layer.

2. The bio-functional air filter medium according to claim 1, wherein the metal salt is an alkali metal salt, a sodium salt, an alkaline earth metal salt or a transition metal salt, of the group zinc, manganese, copper, and iron, a pyrithione derivative and/or a metal salt thereof, wherein the metal salt is of the group consisting of: zinc, manganese, copper, and iron, a pyrithione derivative and/or a metal salt thereof, and/or a quaternary ammonium salt of the general formula NR.sub.4.sup.+X.sup.− or R═NR.sub.2.sup.+X.sup.−, wherein R is an organic residue, wherein R is the same or different, and wherein R is at least one alkoxy group of the general formula —OCH.sub.3, a siloxy group of the general formula R.sup.3Si—O— or an alkoxysilyl group of the general formula R.sup.1R.sup.2R.sup.3Si—O—R.sup.4.

3. The bio-functional air filter medium according to claim 2, wherein the alkoxysilyl group is a trialkoxysilylpropyl group.

4. The bio-functional air filter medium according to claim 2, wherein the pyrithione metal salt is zinc pyrithione.

5. The bio-functional air filter medium according to claim 2, wherein the quaternary ammonium salt comprises a trialkoxysilylpropyl group selected from the group consisting of: dimethyltetradecyl [3-(trimethoxsilyl)propyl] ammonium chloride or 3-(tri-methoxysilyl) propyldimethyl octadecyl ammonium chloride.

6. The bio-functional air filter medium according to claim 1, wherein the anti-microbial material further includes an anti-microbial material selected from the group consisting of: quaternary ammonium compounds, octylisothiazolinone, silver, copper, aluminum compounds, 2-bromo-2-nitropropane-1,3-diol, isothiazolinone compounds, benzoic acid and its derivatives, benzalkonium halides, water-soluble coenzymes, oil-soluble coenzymes, plant extracts, antibiotics, biocidal metals, aliphatic and/or aromatic fatty acids, or combinations thereof.

7. The bio-functional air filter medium according to claim 1, wherein the at least one particle filtration layer, the bio-functional carrier layer and one or more of the at least one mesh support layer are overlaid and co-pleated together, forming the pleated bio-functional air filter medium.

8. The bio-functional air filter medium according to claim 7, wherein the at least one particle filtration layer is arranged upstream of the bio-functional carrier layer, the at least one particle filtration layer forming an inlet flow face of the bio-functional air filter medium, wherein the bio-functional carrier layer is arranged downstream of the at least one particle filtration layer and forms an outlet flow face of the bio-functional air filter medium, wherein a first mesh support layer of the at least one mesh support layer is sandwiched between the at least one particle filtration layer and the bio-functional carrier layer.

9. The bio-functional air filter medium according to claim 7, wherein the at least one particle filtration layer is arranged upstream of the bio-functional carrier layer, the at least one particle filtration layer forming an inlet flow face of the bio-functional air filter medium; wherein a first mesh support layer of the at least one mesh support layer is arranged downstream of the bio-functional carrier layer and forms an outlet flow face of the bio-functional air filter medium. wherein the bio-functional carrier layer is sandwiched between the at least one particle filtration layer and the first mesh support layer.

10. The bio-functional air filter medium according to claim 7, wherein a first mesh support layer of the at least one mesh support layer is arranged upstream of the at least one particle filtration layer, wherein a second mesh support layer of the at least one mesh support layer is arranged downstream of the bio-functional carrier layer and forms an outflow face of the bio-functional air filter medium, wherein the at least one particle filtration layer and the bio-functional carrier layer are sandwiched between the first and the second mesh support layers.

11. The bio-functional air filter medium according to claim 7, wherein the at least one mesh support layer is formed of a material selected from the group consisting of: stainless steel, carbon steel, or anodized, galvanized or coated carbon steel, or a plastic material, wherein the at least one mesh support layer is wire mesh.

12. The bio-functional air filter medium according to claim 1, wherein a quantity of the anti-microbial material in the bio-functional carrier layer is between 3 and 15 g/m.sup.2.

13. The bio-functional air filter medium according to claim 1, wherein the fibers of the bio-functional carrier layer comprise coarse fibers having a diameter in the range of 15-50 μm.

14. The bio-functional air filter medium according to claim 5, wherein when tested according to International Standard ISO 18184, an anti-viral capability of the bio-functional carrier layer, after a virus contact time of less than 2 hours on the bio-functional carrier layer, results in a greater than 90% reduction in viable feline coronavirus when compared to viable feline coronavirus in a carrier layer sample layer lacking the anti-microbial material.

15. The bio-functional air filter medium according to claim 14, wherein when tested according to International Standard ISO 18184, an anti-viral capability of the bio-functional carrier layer, after a virus contact time of less than 2 hours on the bio-functional carrier layer, results in a greater than 98% reduction in viable feline coronavirus when compared to viable feline coronavirus in a carrier layer sample layer lacking the anti-microbial material.

16. An anti-microbial and anti-allergenic bio-functional air filter element for air filtration or HVAC systems, comprising: the bio-functional air filter medium according to claim 2; wherein the at least one particle filtration layer, the bio-functional carrier layer and the at least one mesh support layer are overlaid and co-pleated together, forming the pleated bio-functional air filter medium; a frame arranged on and extending at least partially across an outer circumference of an inlet flow face and an outlet flow face of the bio-functional air filter medium, the frame circumferentially surrounding and supporting the bio-functional air filter medium, forming a unitary replaceable anti-microbial and anti-allergenic bio-functional air filter element.

17. An anti-microbial and anti-allergenic bio-functional air filter element according to claim 16, wherein the frame includes a support grid such that the frame extends fully across at least one of the inflow face and the outflow face.

18. The anti-microbial and anti-allergenic bio-functional air filter element according to claim 16, wherein the quaternary ammonium salt comprises a trialkoxysilylpropyl group selected from the group consisting of: dimethyltetradecyl [3-(trimethoxsilyl)propyl] ammonium chloride or 3-(tri-methoxysilyl) propyldimethyl octadecyl ammonium chloride.

19. The anti-microbial and anti-allergenic bio-functional air filter element according to claim 16, wherein a quantity of the polyphenols in the bio-functional filter layer is between 3 and 15 g/m.sup.2.

20. The anti-microbial and anti-allergenic bio-functional air filter element according to claim 16, wherein the at least one particle filtration layer is arranged upstream of the bio-functional carrier layer, wherein the bio-functional carrier layer is arranged downstream of the at least one particle filtration layer and forms an outlet flow face of the bio-functional air filter medium, wherein a first mesh support layer of the at least one mesh support layer is sandwiched between the at least one particle filtration layer and the bio-functional carrier layer.

21. The anti-microbial and anti-allergenic bio-functional air filter element according to claim 16, wherein the at least one particle filtration layer is arranged upstream of the bio-functional carrier layer, at least one particle filtration layer forming an inlet flow face of the bio-functional air filter medium; wherein a first mesh support layer of the at least one mesh support layer is arranged downstream of the bio-functional carrier layer and forms an outlet flow face of the bio-functional air filter medium; wherein the bio-functional carrier layer is sandwiched between the at least one particle filtration layer and the first mesh support layer.

22. The anti-microbial and anti-allergenic bio-functional air filter element according to claim 16, wherein a first mesh support layer of the at least one mesh support layer is arranged upstream of the at least one particle filtration layer and forms an inflow face of the bio-functional air filter medium, wherein a second mesh support layer of the at least one mesh support layer is arranged downstream of the bio-functional carrier layer and forms an outflow face of the bio-functional air filter medium, wherein the at least one particle filtration layer and the bio-functional carrier layer are sandwiched between the first and the second mesh support layers.

23. The anti-microbial and anti-allergenic bio-functional air filter element according to claim 16, wherein the at least one mesh support layer is formed of a material selected from the group consisting of: stainless steel, carbon steel, or anodized, galvanized or coated carbon steel, or a plastic material, wherein the at least one mesh support layer is wire mesh.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0067] The accompanying Figures, where like reference numerals refer to identical or functionally similar elements throughout the separate views and which together with the detailed description below are incorporated in and form part of the specification, serve to further illustrate various embodiments and to explain various principles and advantages all in accordance with the present invention.

[0068] Features of the present invention, which are believed to be novel, are set forth in the drawings and more particularly in the appended claims. The invention, together with the further objects and advantages thereof, may be best understood with reference to the following description, taken in conjunction with the accompanying drawings. The drawings show a form of the invention that is presently preferred; however, the invention is not limited to the precise arrangement shown in the drawings, but is to be further understood from the disclosure of the specification and the claims.

[0069] FIG. 1 shows a schematic illustration of the bio-functional filter medium having functional layers which are co-pleated together to form a folded, pleated the bio-functional filter medium, consistent with the present inventive disclosure; and

[0070] FIG. 2 shows a schematic perspective illustration of the bio-functional filter medium, as in FIG. 1, arranged within a supporting frame and packed for replaceable installation.

[0071] Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.

DETAILED DESCRIPTION

[0072] In this document, relational terms such as first and second, top and bottom, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms “comprises,” “comprising,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by “comprises . . . a” does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0073] FIG. 1 is a schematic illustration of the bio-functional filter medium according to this inventive disclosure, and configured with anti-microbial, anti-viral and anti-allergenic materials as discussed and presented in the Summary of the Invention section.

[0074] The bio-functional air filter medium 10 includes at least one particle filtration layer 12 configured to retain particles and dust; and at least one bio-functional carrier layer 14 arranged at or against a flow face of the at least one particle filtration layer 12. The at least one bio-functional carrier layer 14 having a substrate 20 which preferably includes spunbond or meltblown fibers and having an air permeability greater than or equal to 3000 l/m.sup.2 s. Preferably the substrate 20 of the at least one bio-functional carrier layer 14 is comprises or consisting of coarse fibers having a diameter in the range of 15-50 μm.

[0075] It is advantageous for the bio-functional air filter medium 10 to have an air permeability greater than or equal to 3000 l/m.sup.2 s, so as to maximize filtration airflow rates by reducing pressure drop. The at least one particle filtration layer 12 and the bio-functional carrier layer 14 are overlaid against each other and co-pleated together (as in FIG. 1), forming a pleated bio-functional air filter medium 20.

[0076] Consistent with the invention, the at least one bio-functional carrier layer 14 includes one or more anti-microbial materials which includes an anti-microbial material selected from the group consisting of: pyrithione, a pyrithione derivative, and/or a metal salt thereof, or other anti-microbial materials presented and discussed in detail in the Summary of the Invention section.

[0077] Consistent with the invention, the at least one bio-functional carrier layer 14 further includes one or more anti-allergenic materials selected from the group consisting of: catechines, tannin or tannic acid derived from wood, apple extracts or citrus bark, apple extracts or citrus fruit extracts, caffeic acid, gallic acid, tea extract, persimmon juice, ellagic acid, tannic acid, hydroxybenzoic acid compounds consisting of (2,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, 2,4,6-trihydroxybenzoic acid), cyanidin, procyanidin, proanthocyanidins, rutin, quercetin, resveratrol, anti-allergenic enzymes or combinations thereof and may include the anti-allergenic materials discussed in detail in the Summary of the Invention section. The anti-allergenic material advantageously binds to and captures allergenic substances in the bio-functional carrier layer so that an allergenic effect is reduced. Preferably, a quantity of polyphenols in the at least one bio-functional filter layer 14 is between 3 and 15 g/m.sup.2.

[0078] The anti-allergenic material and the anti-microbial material are applied onto the at least one bio-functional carrier layer 14 as a coating or introduced into the fibers of the bio-functional carrier layer 14, forming a positive-charged protective shield on the bio-functional carrier layer substrate 20, such that bacterial cells with their negative charge are attracted and inactivated when contacting the bio-functional carrier layer 14, blocking cell function and reproduction.

[0079] The anti-microbial material is configured to block metabolism of bacteria and mold in order to avoid growth of these on the bio-functional carrier layer 14 substrate 20 or filter surface and prevent or decomposition of the anti-allergenic material in the at least one bio-functional carrier layer 14.

[0080] When the at least one bio-functional carrier layer 14 is embodied as two or more bio-functional carrier layers 14, 16, the anti-allergenic material may possibly be coated onto, embedded on or into a first one of bio-functional carrier layers 14 and the anti-microbial material may possibly be coated onto, embedded on or into a second one of bio-functional carrier layers 16.

[0081] FIG. 2 shows a schematic perspective illustration of the co-pleated bio-functional filter medium 22, as in FIG. 1, arranged within a supporting frame 18 and packaged for replaceable installation into an air cleaning device, or HVAC system or air handling system.

[0082] Referring to FIG. 1 with FIG. 2, the bio-functional air filter medium 10 may have the at least one particle filtration layer 12 arranged upstream of the at least one bio-functional carrier layer 14, the at least one particle filtration layer 12 forming an inlet flow face of the bio-functional air filter medium 10. In FIG. 1, the at least one bio-functional carrier layer 14 is arranged downstream of the at least one particle filtration layer 12 or particle filter layer 12 and may form an outlet flow face of the bio-functional air filter medium 10.

[0083] To minimize pressure drop and provide for a high air permeability of greater than or equal to 3000 l/m.sup.2 s, it is preferred that the first filtration or particle layer is overlaid onto the bio-functional carrier layer 14 without adhesives between the layers to bind the layers together. Preferably the layers are loosely arranged on each other and then co-pleated together to form the pleated bio-functional air filter medium 22 having folds or pleats 22 and pleat end edges 26.

[0084] The supporting frame 18, when included, preferably fully surrounds the pleated bio-functional air filter medium 22, enclosing the pleat end edges 26 at lateral sides of the support frame and functional retaining the loosely overlaid filter layer 12 and the at least one bio-functional carrier layer 14 in position and alignment within the support frame 18.

[0085] Other important and chemically related inventive aspects of the at least one bio-functional carrier layer 14 are discussed and presented more fully in the Summary of the Invention section and in the originally presented claims.

[0086] As shown in FIG. 1, it has been found beneficial to add a least one media stiffening support layer (32A, 32B, 32C, 32D), particularly to stiffen the pleats (24) against air flow forces experienced in, for example, HVAC systems or build/room air purifiers, so as to hold the pleated (24) shape for optimum air flow with minimal air flow restriction and a minimal pressure loss. To accomplish this, preferably at least one pleat shape reinforcing mesh support layer (32A, 32B, 32C, 32D) is incorporated into the bio-functional air filter medium (10) and co-pleated together with the at least one particle filtration layer (12) and the at least one bio-functional carrier layer (14), and preferably with any addition layers that may be present, as shown in FIG. 1. Preferably only one media stiffening support layer (32A, 32B, 32C, 32D) is provided, arranged at one of the illustrated at the mesh support layer positions (32, 32B, 32C, or 32D). However, depending upon media types and airflow operating conditions, additional media stiffening support layer(s) may be provided and positioned in any of the illustrated at the mesh support layer positions (32, 32B, 32C, or 32D) to further support the critical pleat structure. Some preferred example constructions are discussed below.

[0087] In one aspect of the invention, the anti-microbial and anti-allergenic bio-functional air filter element (10) is provided with a single mesh support layer (32C) arranged downstream of the bio-functional carrier layer(s) (14) and the at least one particle filtration layer (12) and may form an outlet flow face of the bio-functional air filter medium (10).

[0088] In another aspect of the invention, the at least one particle filtration layer (12) is arranged upstream of the bio-functional carrier layer (14), the at least one particle filtration layer (12) forming an inlet flow face of the bio-functional air filter medium (10) A mesh support layer (32C) is arranged downstream of the at least one bio-functional carrier layer (14) and forms an outlet flow face of the bio-functional air filter medium (10). The at least one bio-functional carrier layer (14,16) is sandwiched between the at least one particle filtration layer (12) and the mesh support layer (32C or 32D).

[0089] In another In another aspect of the invention, a first mesh support layer (32A) is arranged upstream of the at least one particle filtration layer (12) and forms an inflow face of the bio-functional air filter medium (10). A second mesh support layer (32D) is arranged downstream of the at least one bio-functional carrier layer (14) and forms an outflow face of the bio-functional air filter medium (10). The at least one particle filtration layer (12) and the bio-functional carrier layer(s) are sandwiched between the first (32A) and the second (32D) mesh support layers.

[0090] The mesh support layer(s) (32A, 32B, 32C, 32D) cooperate to support the shaped pleats against air flow forces, supporting the pleat shape to structurally support the filter layers against airflow forace and to maximize filter layer face filtration area by preventing pleat collapse onto the flow faces of the filter media. The mesh support layer(s) (32A, 32B, 32C, 32D) are preferably embodied as any of: a wire mesh, a woven wire mesh, a metallic woven wire mesh, a metallic metal screen, or a plastic molded mesh screen. In some aspects of the invention, a woven wire mesh may alternately be made as a woven wire cloth having wire threads woven at the right angles. In some similar aspects of the invention, the wire threads are woven to overlay or intersect at acute or obtuse angles.

[0091] In some aspects of the invention, the mesh support layer is formed of a material selected from the group consisting of: stainless steel, carbon steel, or anodized, galvanized or coated carbon steel, copper, silver, or a plastic material, or molded as a plastic grid.

[0092] In some aspects of the invention, the mesh support layer (32A, 32B, 32C, 32D) may also be coated with an anti-microbial material.

[0093] As discussed earlier, the media stiffening support layer(s) (32A, 32B, 32C, 32D) may be provided and positioned in any of or all of, the illustrated at the mesh support layer positions (32, 32B, 32C, or 32D), as is shown in FIG. 1.

[0094] In the foregoing specification, specific embodiments of the present invention have been described. However, one of ordinary skill in the art appreciates that various modifications and changes can be made without departing from the scope of the present invention as set forth in the claims below. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of the present invention. The benefits, advantages, solutions to problems, and any element(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential features or elements of any or all the claims. The invention is defined solely by the appended claims including any amendments made during the pendency of this application and all equivalents of those claims as issued.