WO2022185329A1

WO2022185329A1 - Pocket filters

Info

Publication number: WO2022185329A1
Application number: PCT/IN2021/051153
Authority: WO
Inventors: Santhosh Kumar PULIPARA DAMODARAN
Original assignee: Pulipara Damodaran Santhosh Kumar
Priority date: 2021-03-02
Filing date: 2021-12-09
Publication date: 2022-09-09

Abstract

The present invention relates to improved anti-microbial and antiviral treated removal pocket filters for filter systems. More specifically the present invention is about constructing pocket filters and also a method of coating or applying anti-microbial coatings on the exposed non-woven layers along-with filter media which works effectively to destroy the microbes collected by the filter and also improves the filtration efficiency.

Description

POCKET FILTERS FIELD OF THE INVENTION: [0001] The present invention relates to a pocket filter and filter assemblies, more particularly, to antimicrobial/antiviral coatings on non‐woven media that is found on either side of the filtration media in HVAC filtration systems. BACKGROUND: [0002] Pocket type air filters are widely used in HVAC installation. Several technologies are existing to construct filter assemblies by adding anti viral and anti microbial coatings to nonwoven middle or intermediate layers along with filter media which works effectively to destroy the microbes collected by the filter. [0003] It is possible to improve some of the properties of the pocket filters by application of antiviral and anti microbial coatings to the spunbond non woven found on either side ( The main filter media is between these two layers) of the high efficiency filter media ( which could be melt blown or micro fine glass fiber or nonwoven polyester fiber type) which is used in pocket type filters generally. [0004] The safe way to attach the coated anti-viral and anti-microbial spunbond polypropylene layer is by a spaced ultrasonic welding or quilting or by stitching together. A pocket type filter generally has multiple layers of nonwoven filter media arranged in graduated density. The main filtration layer is where the majority of microbes get collected. By attaching the anti viral and anti microbial coated nonwoven to it, would make contact with the microbe on the outer area of the high efficiency filter media and destroy it. This is found to be effective. Adding on both sides of the high efficiency layer gives better protection. [0005] However, the existing pocket anti‐microbial coatings are done in the middle filtration material. The outer layers are not coated with anti‐microbial/antiviral agents. This will increase the filtration efficiency of filters because some of the microbes gets killed in the first layer itself by impaction. The more important benefit is that the whole filter itself is decontaminated. [0006] Pocket filters of the present invention are designed such that there is a filtration media sandwiched between two layers of nonwoven. The invention addresses the problem of contamination of pocket filters and growth of bacteria and other microbes on the surfaces of the pocket filter that are exposed to the environment. [0007] Existing pocket filters do not have any coatings on the outer upstream and downstream layer. So even if the inner filtration layer like melt blown material is coated with antimicrobial agents, with the right humid conditions, they can grow on the other two layers which is exposed to external air stream and create hazard. [0008] Air enters a pocket and first impacts the upstream non woven layer and then passes to the next high filtration layer and finally to the outer non woven layer. [0009] It is these two non woven layers which are exposed outside and any growth can contaminate the environment while disposing and also the person who is handling. [0010] During replacement of these filters, handling them is high risk because the exposed upstream and downstream non woven can have microbial growth. But if these layers are coated with agent, there would be very low presence of microbes. [0011] Respiratory infections can be transmitted through droplets of different sizes: when the droplet particles are >5‐10 μm in diameter they are referred to as respiratory droplets. These droplets which are larger in size impact the upstream layer. If there is high humidity this can lead to the growth of the microbes in the environment on the upstream and eventually spread to the air duct. Therefore this novel method reduces the chance of spread considerably. OBJECTIVES OF THE INVENTION: [0012] The primary objective of the present invention is to provide a pocket filter coated with antimicrobial agents on both the upstream and downstream side. [0013] The secondary objective is to provide a pocket filter that will result in decontamination of the filter by adding on both sides of the high efficiency layer which provides improvised protection. [0014] Another objective of the present invention is the utilization of the pocket filter in HVAC filtration systems. SUMMARY: [0015] The present invention is about constructing pocket filters and also a novel method of coating or applying anti viral and anti microbial coatings on the exposed nonwoven layers along with filter media which works effectively to destroy the microbes collected by the filter. [0016] In another aspect of the present invention it is possible by attaching the anti viral and anti microbial coated layers to both sides of the high efficiency filter media which could be melt-blown or applied to micro fine glass fiber or nonwoven polyester fiber type which are generally used in pocket type filters. [0017] In another aspect of the current invention the attaching of the anti viral and anti microbial layer by a spaced ultrasonic welding or quilting or by stitching together and provides the safest method of constructing [0018] In another aspect of the present invention the pocket type filter comprises of multiple layers of nonwoven filter media arranged in graduated density. The main filtration layer is where the majority of microbes get collected and attaching the anti viral and anti microbial coated nonwoven media to it, enables the contact with the microbe on the outer area of the high efficiency filter media and prevent from entering inside and this method is more effective. [0019] These objectives and advantages of the present invention will become more evident from the following detailed description when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS: [0020] Other features and advantages of the present invention will become apparent from the detailed description of the invention which follows, when considered in light of the accompanying drawings in which: [0021] Fig.1 illustrates the pocket filter of the present invention; REFERENCE NUMERALS: 100 - Non-woven coated and middle layers 101 - Filter media 102 - Frame 103 - Airflow DETAILED DESCRIPTION OF THE INVENTION: [0022] The present invention discloses a pocket filter comprising of three main parts. That is the pocket frame, the pocket rings, and the stitched pockets. [0023] In one embodiment of the present invention the pocket filters as shown in Fig 1 of the present invention ensures efficient filtration of your pocket filter. The pocket frame is the outer part of your pocket filter which is mostly of steel. This frame protects the other components holding them firmly. Also, the frame ensures that the components are in place when pressurized fluid flows into the pocket filter. The pocket rings are the points at which the pockets stitch to the frame. They are generally j‐shaped and surround the frame. These pocket rings provide an additional layer of firmness to the pocket filter which ensures the pockets does not detach during filtration process. [0024] The pocket filter has filter assemblies which filter the fluid ensuring removal of all the contaminants. The pockets are wedge-shaped which enhances filtration of the air entering, more specifically filtering of the pollutants and pathogens. [0025] In a specific embodiment of the present invention the method of fabrication of the pocket filters consists of the following steps. First, is the shaping of a material which can either be woven or non‐woven into pockets having a wedge‐like shape with the opening being wider than the bottom. Also, the purpose of this is to ensure maximum filtration as the fluid flows through it. Depending on the necessity and requirement the size can be customized and has provision for the same (big or small pockets). This is followed by sewing of the pockets into pocket rings. The pocket rings offer support to the pockets and is all along with the pockets ensuring stiffness and firmness. Finally the pocket rings are attached to the frame. The frame may either be rectangular or square. The frame plays a vital role in holding all the components together. This ensures that during filtration, the pockets do not detach and collapse. Also the pocket filters of the current invention are ultrasonically sealed and do not require any specific binders. [0026] As illustrated in fig 1 the filter media is made into bag-like structures and the frame of the pocket filters are made of metal plastics or cardboard materials and the airflow is though the pockets. [0027] The upstream and downstream outer non woven layers are exposed whereas the high efficiency filter media is sandwiched between these two non woven layers. The upstream and downstream outer non woven layers are exposed. These can deactivate pathogens that make contact with these layers and improve the bacterial filtration efficiency (BFE) and viral filtration efficiency (VFE). The BFE and VFE tests are conducted by introducing a colony of pathogens on the first layer and checking the presence in the outermost surface of the final layer. [0028] The present invention incorporates spun bond fibers, specifically spun bond polypropylene which are continuous fibers of synthetic materials with diameters of 10-25µm. [0029] The another embodiment of the present invention the filters are 1-3µm meltblown fibers which are typically <5µm synthetic staple fibers, though they may be formed as filament fibers.Here most of the pathogens get destroyed in the first non woven layer and even if a small quantity passes through the high efficiency filter media, the downstream non woven layer would deactivate them. The efficiencies of more than 99.99 percent is observed. [0030] During replacement of these filters, handling them is high risk because the exposed upstream and downstream non woven can have microbial growth. But if these layers are coated with agent, there would be very low presence of microbes. [0031] Test methods are carried to obtain the results of the pocket filters from Microbe Investigations AG. [0032] The effect/property of quantitative antibacterial test on textiles according to ISO 20743:2013 and the testing parameter for filter is Bacterium: Staphylococcus aureus (ATCC 6538P) and the effect/property of quantitative antiviral test on textiles according to ISO 18184:2019 Betacoronavirus 1, strain OC43 (ATCC VR1558) are performed. [0033] Table 1 lists the sample description wherein the material tested is non- woven for air filters

[0034] Table 2 lists the testing parameter Staphylococcus aureus

[0035] Table 3 lists the testing parameter Betacoronavirus

[0036] The test results were found to be very good effect level. [0037] In the test ISO 20743, the "Nonwoven-Air Filter" sample showed excellent antibacterial activity against Staphylococcus aureus. [0038] In the test ISO 18184, the "Nonwoven-Air Filter" sample showed good antiviral activity against Betacoronavirus 1 (Strain: OC43) [0039] As depicted the pocket filters of the present invention have improvied and enhanced effect against pathogens. The said layer of the present invention contains two-sided coating which has a decontamination effect. The report provided from the Swiss Testing Agency MIS validates the claim of reduced contamination. [0040] The values given in the table 1 to 3 shows the reduction in the growth of the bacteria / virus introduced into the filter to test - Staphylococcus aureus introduced had a log cfu(colony forming unit) of 4.69 initially. Log cfu after 18 hrs is 7.08. but the tested sample with Antibacterial coating showed a reduction up to log cfu 2.36. As per their parameters there is a 99.998% reduction shown in the bacterial growth in the tested sample. [0041] The log reduction sample value of 4.70 is estimated on the basis of the % of reduction of bacteria. If there is 90% bacterial reduction(or 10 fold reduction) then the log reduction is valued at 1, if there is 99% bacterial reduction (or 100 fold reduction) then log reduction is 2, if bacterial reduction is 99.9% (or 1000 fold reduction) then the log reduction is 3 and if the bacterial reduction is 99.99% (or 10000 fold) then log reduction is 4. In the sample tested, the bacterial reduction is 99.998, therefore log reduction is shown as 4.70. [0042] The antiviral report also has a similar valuation done on the basis of the reduction in virus and the sample is found to show 99.091% reduction in growth of virus. [0043] While the foregoing written description of the invention enables one of ordinary skill to make and use what is considered presently to be the best mode thereof, those of ordinary skill will understand and appreciate the existence of variations, combinations, and equivalents of the specific embodiment, method, and examples herein. The invention should therefore not be limited by the above described embodiment, method, and examples, but by all embodiments and methods within the scope and spirit of the invention as claimed.

Claims

We Claim: 1. A system of fabricating an anti-pathogenic pocket filter for HVAC and HEPA filtration characterized with: filter media wherein the said filter media is either be woven or non‐ woven into pockets; wedge‐like shaped pockets with the opening being wider than the bottom; pocket rings attached to the frame; 2. The system of fabricating an anti-pathogenic pocket filter for HVAC and HEPA filtration as claimed in claim 1 wherein the said frame is the outer part of the pocket filter made of steel. 3. The system of fabricating an anti-pathogenic pocket filter for HVAC and HEPA filtration as claimed in claim 1 wherein the said frame holds the other components firmly. 4. The system of fabricating an anti-pathogenic pocket filter for HVAC and HEPA filtration as claimed in claim 1 wherein the said frame ensures that the components are in place when pressurized fluid flows into the pocket filter. 5. The system of fabricating an anti-pathogenic pocket filter for HVAC and HEPA filtration as claimed in claim 1 wherein the said pocket rings are the points at which the pockets stitch to the frame and are generally j‐shaped and surround the frame and the pocket rings provide an additional layer of firmness to the pocket filter which ensures the pockets does not detach during filtration process. 6. The system of fabricating an anti-pathogenic pocket filter for HVAC and HEPA filtration systems as claimed in claim 1 wherein the said filter media is made into bag-like structures and the frame of the pocket filters are made of metal plastics or cardboard materials and the airflow is though the pockets. 7. The system of fabricating an anti-pathogenic pocket filter for HVAC and HEPA filtration systems as claimed in claim 1 wherein the said layers are spun bond fibers, specifically spun bond polypropylene which are continuous fibers of synthetic materials with diameters of 10-25µm. 8. The system of fabricating an anti-pathogenic pocket filter for HVAC and HEPA filtration systems as claimed in claim 1 wherein the said filters are 1-3µm meltblown fibers which are typically <5µm synthetic staple fibers, though they may be formed as filament fibers 9. The system of fabricating an anti-pathogenic pocket filter for HVAC and HEPA filtration as claimed in in claim 1 wherein the bacterial reduction is 99.998, therefore log reduction is shown as 4.70 and the viral reduction is found to show 99.091%. 10. The method of fabricating an anti-pathogenic pocket filter for HVAC and HEPA filtration comprising the steps of: shaping of a material which can either be woven or non‐woven into pockets having a wedge‐like shape with the opening being wider than the bottom; upstream and downstream outer non-woven layers are exposed whereas an high efficiency filter media is sandwiched between these two non woven layers; and are exposed which deactivate pathogens that make contact with the said layers. sewing of the pockets into pocket rings; attaching the pocket rings to the frame and are ultrasonically sealed and do not require any specific binders.