WO2021186318A2

WO2021186318A2 - Filtration system

Info

Publication number: WO2021186318A2
Application number: PCT/IB2021/052123
Authority: WO
Inventors: Matthew W. Gorrell; Paul D. ODEGARD; John B. STENDER; Yaohua GAO; Stephen M. Sanocki; John M. Brandner; David C. Raithel
Original assignee: 3M Innovative Properties Company
Priority date: 2020-03-18
Filing date: 2021-03-15
Publication date: 2021-09-23
Also published as: WO2021186318A3

Abstract

Filtration systems are described. In particular, a filtration system for filtering airborne particles includes an accumulation layer defining an intake surface and an exhaust surface, the accumulation layer defining an acute angle with a gravitational direction. The filtration system also includes a plurality of linear conduits included in the accumulation layer, the linear conduits being disposed in parallel with one another.

Description

FILTRATION SYSTEM

Background

Filters are used for many purposes, such as removing small suspended particulates from fluid flows. Filtration systems can include filters and accumulation layers.

Summary

In some aspects, a filtration system is disclosed. The filtration system can include an accumulation layer defining an intake surface and an exhaust surface. The accumulation layer can define an acute angle with a gravitational direction. The filtration system can further include a plurality of linear conduits included in the accumulation layer, and the linear conduits can be disposed in parallel with one another.

In some aspects, a filtration system is disclosed. The filtration system can include an accumulation layer defining an intake surface and an exhaust surface, and the accumulation layer can define an acute angle with a gravitational direction. The filtration system can also include a plurality of conduits in the accumulation layer, and a filter media can face the exhaust surface of the accumulation layer. The filter media can be disposed downstream of the accumulation layer.

Brief Description of the Drawings

FIG. 1 is schematic system view of a filter securement system including cooking equipment and an exhaust system, according to exemplary embodiments of the present disclosure.

FIG. 2 is a schematic perspective view of an accumulation layer and a fluid collection device, according to exemplary embodiments of the present disclosure.

FIG. 3 is a schematic perspective view of another accumulation layer and a fluid collection device, according to exemplary embodiments of the present disclosure.

FIG. 4 is a schematic perspective view of an accumulation layer, a filter media and a fluid collection device, according to exemplary embodiments of the present disclosure.

FIGS. 5A and 5B are schematic side views of angular arrangements of an accumulation layer, according to exemplary embodiments of the present disclosure.

Detailed Description

In the following description, reference is made to the accompanying drawings that form a part hereof and in which various embodiments are shown by way of illustration. The drawings are not necessarily to scale. It is to be understood that other embodiments are contemplated and may be made without departing from the scope or spirit of the present description. The following detailed description, therefore, is not to be taken in a limiting sense.

Filters can be used in a wide range of applications. In some embodiments, filters may be designed for general air filtration to filter primarily airborne particulates. For example, filters may be designed to filter particles smaller than 10 micrometers in diameter, smaller than 5 micrometers in diameter, smaller than 2.5 micrometers in diameter, smaller than 1.0 micrometer in diameter, smaller than 0.5 micrometers in diameter or smaller than 0.3 micrometers in diameter, among others.

Filters can also be used in a specific location, such as an exhaust hood, for grease filtering in a commercial cooking environment. In commercial kitchens, grease capture in exhaust hoods may be important for health, safety and environmental reasons. However, grease buildup in and around an exhaust hood or an exhaust system may pose a fire hazard.

To mitigate the hazard, commercial kitchens typically use airflow interrupters or disrupters, such as baffles, made of a non-flammable material, such as a metal or metal alloy, including stainless steel, galvanized steel or aluminum. The baffle can prevent fire from spreading from the cooking surface and the exhaust system. However, aerosolized grease can travel through the complicated path created by the baffles, resulting in grease accumulating on the baffles and in the ducts. Grease buildup on the baffles requires regular cleaning to maintain the baffle’s effectiveness as a fire barrier and a grease collector. Aesthetically, visible grease on a commercial hood baffle can also be undesirable. Removing, cleaning, and reinstalling the baffles can be time consuming, labor-intensive, expensive and dangerous. Thus, versus conventional baffles, the present disclosure can provide a grease-trapping solution that reduces or prevents the buildup of grease on exhaust system components, is light and easy to install in an exhaust hood and can facilitate the easy replacement of filter media within an exhaust hood in a location traditionally occupied by baffles. Other benefits and uses are also foreseen.

The present disclosure provides a filtration system which can include a filter media and an accumulation layer. The filter securement system can receive and retain the filter media and/or the accumulation layer in an exhaust hood for the filtration of grease droplets, although other uses and locations for the filter media and accumulation layer are within the scope of this disclosure. Such a filter media and accumulation layer can replace traditional baffles in an exhaust hood, thereby requiring minimal or no modifications to existing exhaust systems. The accumulation layer, as will be described below in further detail, can gather grease and other fluid droplets thereon and re-direct said droplets to a fluid collection device. When the accumulation layer is disposed at particular angles relative to a ground surface, cooking surface and/or a gravitational direction, the accumulation layer can gather and re-direct grease particles in such a way that the accumulated droplets do not fall from conduits of the accumulation layer. Additionally, the filter media received and/or secured by the securement system can prevent flames from passing through the filter media and reduce the buildup of grease on portions of the exhaust system downstream of the filter media. For clarity, moving from the cooking equipment through the exhaust system and past the blower can be defined as moving downstream, while moving in the opposite direction can be defined as moving upstream.

FIG. 1 is a schematic sectional view of a filtration system 40 including cooking equipment 50 and an exhaust system 54. The cooking equipment 50 can be an oven, stove, grill, fryer, broiler or any other commonly used cooking apparatus known to those skilled in the art and can further define a cooking surface 52. The exhaust system 54 can include an exhaust hood 58 defining an exhaust hood flange 60. A securement system 78, which can include the exhaust hood flange 60, can releasably or permanently retain a filter media 80 and an accumulation layer 100. The exhaust hood 58 can be positioned to capture all or a portion of grease and other particulates generated by the use of the cooking equipment 50. A blower 66 can, via a duct 62, create a reduced-pressure area proximate the cooking equipment 50 (relative to ambient pressure) that can encourage grease and other particulates generated by use of the cooking equipment 50 to enter the exhaust system 54 via the exhaust hood 58. In such a system, as illustrated in FIG. 1, air, gasses, grease and/or particulates can travel into the exhaust system 54 via the exhaust hood 58 (and filter media 80 and accumulation layer 100), as represented by arrow 70. The filtered air, gasses and any remaining grease and/or particulates can then pass through the duct 62 and blower 66 before exiting the exhaust system 54, as represented by arrow 74. 70 and 74 represent portions of a fluid flow traveling from the cooking surface 52, through the exhaust hood 58, accumulation layer 100, and out through the rest of the exhaust system 54.

It is to be understood that securement systems 78, accumulation layers 100 and filter media 80 releasably mounted on, proximate, adjacent and/or in contact with the exhaust hood flange 60 or exhaust hood 58 are within the scope of this disclosure. A filter media intake side 104 facing upstream and a filter media exhaust side 108 facing downstream, along with an accumulation layer intake side 112 facing upstream and an accumulation layer exhaust side 116 facing downstream are also illustrated in FIG. 1.

FIG. 2 illustrates a schematic perspective view of the accumulation layer 100, also showing the accumulation layer intake side 112 and accumulation layer exhaust side 116. The intake and exhaust sides 112, 116 can be disposed on substantially opposed sides of the accumulation layer 100. FIG. 2 also illustrates an accumulation layer first side 120 and an accumulation layer second side 124, and the sides 120, 124 can be disposed at substantially opposed sides of the accumulation layer 100. A frame 130, conduits 134 and secondary members 138 are also shown. The frame 130 can be of any suitable shape, material or construction such that it can support the conduits 134. Conduits 134 can be disposed within or on the frame 130. In some embodiments, some or all of the conduits 134 are linear, or substantially linear. In some embodiments, some or all of the conduits 134 are parallel, or substantially parallel, with one another. In some embodiments, some or all of the conduits 134 are parallel, or substantially parallel, with lateral sides 135, 136 of the frame 130. In some embodiments, at least some of the conduits 134 extend from the accumulation layer first side 120 to the accumulation layer second side 124. In some embodiments, the accumulation layer 100 does not include a frame 130.

In some embodiments, some of all of the conduits 134 include an enclosed or partially- enclosed lumen or interior channel for conveying accumulated grease droplets. In some embodiments, some or all of the conduits 134 include at least some, or fully consist of, convex shapes and do not include a partially-enclosed lumen or interior channel. Instead, these conduits 134 can rely at least partially on fluid properties of the grease droplet (such as surface tension), material properties of the conduit 134 and/or a shape of the conduit 134 to convey the grease droplets.

FIG. 2 further illustrates secondary members 138. The secondary members 138 can be coplanar, or substantially coplanar, with the conduits 134. In some embodiments, at least some of the secondary members 138 are non-parallel, or substantially non-parallel, to at least some of the conduits 134. In some embodiments, at least some of the secondary members 138 are perpendicular, or substantially perpendicular, to at least some of the conduits 134. In some embodiments, at least some of the secondary members 138 are parallel, or substantially parallel, with one another. In some embodiments, at least some of the secondary members 138 are joined or connected to at least some of the conduits 134. In some embodiments, at least some of the secondary members 138 are joined with at least some of the conduits 134 to form a mesh-like material. In some embodiments, the secondary members 138 and conduits 134 can include commercially available ADFORS Clear Advantage window screen. A fluid collection device 150 is shown in FIG. 2, and will be described below in further detail. The fluid collection device 150 can include a trough or other collection shape and can span a length of the accumulation layer second side 124, a length of the secondary members 138, a length between lateral sides 135, 136 or any other length.

The conduits 134 and secondary members 138 can include different materials or the same material. In particular, the conduits 134 and/or the secondary members 138 can include fiberglass, steel, stainless steel, aluminum, aluminum foil, perforated aluminum foil, metals, metal alloys, polymers, carbon, ceramics, organic materials, braided materials, flame-resistant materials, Nextel, or any other material known to those skilled in the art. The conduits 134 and/or the secondary members 138 can be spaced at irregular spacings from one another or at regular spacings of, of about, at least or at most: 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2.0mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, 3.0mm, 3.1mm, 3.2mm, 3.3mm, 3.4mm, 3.5mm, 3.6mm, 3.7mm, 3.8mm, 3.9mm, 4.0mm, 4.5mm, 5.0mm, 5.5mm, 6.0mm, 6.5mm, 7.0mm, 7.5mm, 8.0mm, 8.5mm, 9.0mm, 9.5mm or 10.0mm.

The conduits 134 and/or the secondary members 138 can have a constant, substantially constant or average diameter, of about, at least or at most: 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2.0mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, 3.0mm, 3.1mm, 3.2mm, 3.3mm, 3.4mm, 3.5mm, 3.6mm, 3.7mm, 3.8mm, 3.9mm, 4.0mm, 4.5mm, 5.0mm, 5.5mm, 6.0mm, 6.5mm, 7.0mm, 7.5mm, 8.0mm, 8.5mm, 9.0mm, 9.5mm or 10.0mm.

In non-limiting embodiments, cross-sections of at least some of the conduits 134 and/or the secondary members 138 can be substantially circular, ovular, triangular, rectangular, pentagonal, hexagonal, heptagonal, octagonal, organic, geometric, semi-circular, crescent-like, parallelogrammatic, quadrilateral, rhomboid and/or stadium-like. Further, in some embodiments, some of the conduits 134 and/or secondary members 138 define substantially the same shape while in other embodiments, at least some of the conduits 134 and/or secondary members 138 define two or more different shapes.

The securement system 78 can include conventional exhaust hood flanges 60 and/or any other mechanical, magnetic, chemical or adhesive connection technology known to those skilled in the art. Additionally, the securement system 78 can releasably secure the accumulation layer 100, filter media 80 and/or a baffle within the exhaust hood 58.

FIG. 3 illustrates an embodiment where the frame 130 includes conduits 134 while being devoid of secondary members 138.

FIG. 4 illustrates an embodiment including conduits 134 and secondary members 138, and further showing a possible relative arrangement between the filter media 80 and the accumulation layer 100. While FIG. 4 shows the filter media 80 and accumulation layer 100 as being in contact, it is to be understood that the filter media 80 and accumulation layer 100 can be in contact, proximate, joined or separated by any distance. Additionally, while FIG. 4 illustrates the filter media 80, a conventional baffle can also be disposed adjacent, proximate or joined to the accumulation layer 100.

FIG. 5A is a schematic illustration of the accumulation layer 100 in relation to various surfaces. In some embodiments, a reference line 160 can schematically represent a normal, or perpendicular, line to various surfaces. In some embodiments, the reference line 160 is normal to a ground surface 162. In some embodiments, the reference line 160 is normal to the cooking surface 52. In some embodiments, the reference line 160 is substantially parallel to a gravitational direction G. An angle a can be formed between the reference line 160 and the accumulation layer 100. In some embodiments, the angle a is an acute angle. As shown in FIG. 5A, the angle a can be defined as opening generally in the gravitational direction G, towards the ground surface 162 and/or towards the cooking surface 52. As shown in FIG. 5B, the angle a can be defined as facing generally against the gravitational direction G, away from the ground surface 162 and/or away from the cooking surface 52. In some embodiments, the angle a can be, can be about, can be at least or can be at most: 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85 or 89 degrees.

In some embodiments, the filter media 80 includes fibers 84 that form a non-woven and/or non-knitted material to thus form all or a portion of the filter media 80. The non-woven and/or non-knitted material can describe materials that are bonded together by chemical, mechanical, heat or solvent treatments, rather than by knitting or weaving. The non-woven material can be lofty, carded, air-laid or mechanically bonded (such as spun-lace, needle- entangled or needle-tacked). The non-woven material can be bonded (e.g., the fibers are bonded to one another at various locations) or non-bonded.

One or more the fibers 84, or another component of the filter media 80, can include a heat-setting material or a melt material that provides some or all of the bonding in the non- woven material and/or filter media 80, such as a flake, powder, fiber or a combination thereof. The heat-setting material can include any suitable thermoplastic or thermoset polymer, such as polyester, polyethylene terephthalate (PET), polypropylene (PP) or a combination thereof. After melting and/or heat bonding, the flake, powder and/or fiber can melt and bond fibers 84 together, increasing a strength and stability of the filter media 80.

The filter media 80 and fibers 84 can include a Flame-Resistant (FR) material, Oxidized Polyacrylonitrile fiber (OPAN), modacrylic, flame-resistant rayon, Polyacrylonitrile (PAN), Polyphenylene Sulfide (PPS), Polyethylene Terephthalate (PET), Polypropylene (PP), Kapok Fiber, Poly Lactic Acid (PLA), cotton, nylon, polyester, rayon (e.g., non-flame-retardant rayon), wool, basalt, fiberglass, ceramic or a combination thereof. In some embodiments, the filter media 80 and fibers 84 can include a conventional filter media material (such as polyolefin) that has been treated or coated to be flame-resistant, a conventional filter media material and a metal mesh and/or a flame-resistant barrier. In some embodiments, the fibers 84 can be bicomponent fibers, or fibers made of more than one material, such as those listed in this disclosure. In various embodiments, the filter media 80 can be pleated, non-pleated and/or multilayered (which can include a multi-layer web including a woven layer, such as a woven basalt layer), based upon application.

The filter media 80 and fibers 84 can further include a coating, a heat-setting or melt material (e.g., powder, flakes and/or fibers), a metal fiber, a glass fiber, a ceramic fiber, an aramid fiber, a sorbent, an intumescent material (e.g., a fiber or a particle), mica, diatomaceous earth, glass bubbles, carbon particles or a combination thereof. Examples of flame-resistant materials include any polymer designated as flame-retardant (e.g., as pure materials or as compounds including the materials), aluminum, polyphosphate, phosphorus, nitrogen, sulfur, silicon, antimony, chlorine, bromine, magnesium, zinc, carbon or a combination thereof. Flame- resistant materials can be halogen-containing flame retardants or non-halogenated flame retardants. Examples of coatings or additives can include expandable graphite, vermiculite, ammonium polyphosphate, alumina trihydrate (ATH), magnesium hydroxide (Mg(OH)2), aluminum hydroxide (AI(OH)3), molybdate compounds, chlorinated compounds, brominated compounds, antimony oxides, organophosphorus compounds or a combination thereof.

In some embodiments, the filter media 80 and fibers 84 can include airlaid nonwoven web prepared using 90% oxidized polyacrylonitrile (OPAN) staple fiber with a denier diameter of 5.0dtexx 60mm (commercially available under the trade designation ZOLTEK™ OX) and 10% binding fiber (high temperature polyester binding or melty fiber with a denier diameter of 6.7dtex x 60 mm, commercially available under the trade designation TREVIRA® T270) with an area weight of 150 grams per square meter.

In some embodiments, the filter media 80 and fibers 84 can include airlaid nonwoven web prepared using nylon staple fiber with a denier diameter of 1000 dtex, or denier, and 10% binding fiber (commercially available under the trade designation TREVIRA® T270) with an area weight of 550 grams per square meter.

In some embodiments, the filter media 80 and fibers 84 can include airlaid nonwoven web prepared using 40% 5.0dtex x 60 mm OPAN staple fiber, 40% 500 dtex, or denier, PET staple fiber (commercially available from David C. Poole Company, Inc.), and 20% 15 dtex, or denier, binding fiber, such as is commercially available from Huvis with an area weight of 225 grams per square meter.

In various embodiments, the filter media 80 can have any suitable overall weight or density, such as about, less than, equal to or greater than: 20, 40, 60, 80, 100, 125, 150, 175, 200, 225, 250, 275, 300, 325, 350, 375 or 400 g/m². The OPAN, FR rayon or a combination thereof, can be greater than, less than, equal to or about: 10, 20, 30, 40, 50, 60, 70, 80, 90 or 100 wt% of the filter media 80.

In some embodiments, the filter media 80 can be designed to be used (sufficiently saturated with airborne particulates) one time and discarded, washed once sufficiently saturated and re-used or washed once sufficiently saturated and re-used a pre-specified and finite number of times.

In operation, grease generated from the cooking equipment or another source rises, or is suctioned, towards the accumulation layer and filter media. Airborne droplets of grease can condense on the accumulation layer, and specifically on the conduits. Upon reaching a suitable size, the droplets can collect into larger drops which can then travel down the conduits, due to the angle a, conduit shape, conduit material, fluid properties and surface tensile properties of the drops. Upon reaching a lower or second end of the conduit or frame, the grease drops can be collected in a fluid collection device to be discarded through any technique known to those skilled in the art. In this manner, a portion of the grease generated from the source is collected prior to the grease interacting with the filter media. The filter media is thus exposed to a lesser amount of airborne grease droplets and accordingly can provide a longer and more efficient useful life before cleaning or disposal is necessary. Additionally, due to the angle a and the condensing and traveling of the droplets on the conduits, grease drops are prevented from falling back onto the cooking surface or another surface.

The present disclosure also provides numerous benefits over a conventional exhaust filtration system having one or more baffles without an accumulation layer. In a conventional filtration system, aerosolized grease travels through the baffles and condenses on the baffles and on other surfaces of the exhaust system. This grease buildup on the baffles requires regular cleaning to maintain the baffle’s effectiveness as a fire barrier and a grease collector, and to maintain appealing aesthetics. The baffles must be frequently removed for baffle and duct cleaning in a time-consuming, labor-intensive and expensive process. Thus, versus conventional baffles, the present disclosure can provide a grease-trapping solution that reduces or prevents the buildup of grease on exhaust system components, is light and easy to install in an exhaust hood and can facilitate the easy replacement of filter media within an exhaust hood in a location traditionally occupied by baffles.

The terms and expressions that have been employed are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the embodiments of the present disclosure. Thus, it should be understood that although the present disclosure has been specifically disclosed by specific embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those of ordinary skill in the art, and that such modifications and variations are considered to be within the scope of embodiments of the present disclosure. The complete disclosures of the patents, patent documents, and publications cited herein are incorporated by reference in their entirety as if each were individually incorporated. To the extent that there is any conflict or discrepancy between this specification as written and the disclosure in any document that is incorporated by reference herein, this specification as written will control.

Claims

What is claimed is:

1. A filtration system for filtering airborne particles, comprising: an accumulation layer defining an intake surface and an exhaust surface and the accumulation layer defining an acute angle with a gravitational direction; and a plurality of linear conduits included in the accumulation layer, the linear conduits being disposed in parallel with one another.

2. The filtration system of claim 1 , wherein the accumulation layer includes secondary members that are not parallel with the linear conduits.

3. The filtration system of claim 2, wherein at least one secondary member is joined with the linear conduits.

4. The filtration system of claim 2, wherein at least one secondary member is perpendicular to the linear conduits.

5. The filtration system of claim 1 , wherein the linear conduits include fiberglass.

6. The filtration system of claim 1 , wherein the linear conduits include stainless steel.

7. The filtration system of claim 1, wherein at least some linear conduits extend from a first end of the accumulation layer to an opposed second end of the accumulation layer.

8. The filtration system of claim 1 , wherein the linear conduits are non-parallel with the gravitational direction.

9. The filtration system of claim 1 , wherein the linear conduits include aluminum.

10. The filtration system of claim 1 , wherein a fluid collection device is disposed proximate one end of the accumulation layer.

11. A filtration system for filtering airborne particles, comprising: an accumulation layer defining an intake surface and an exhaust surface and the accumulation layer defining an acute angle with a gravitational direction; a plurality of conduits included in the accumulation layer; and a filter media facing the exhaust surface of the accumulation layer, the filter media being disposed downstream of the accumulation layer.

12. The filtration system of claim 11 , wherein the conduits are linear conduits disposed in parallel with one another.

13. The filtration system of claim 11 , wherein the filter media includes a flame-resistant material.

14. The filtration system of claim 11 , wherein the filter media includes airlaid nonwoven fibers including oxidized polyacrylonitrile staple fibers and polyester fibers.

15. The filtration system of claim 11 , wherein the filter media includes airlaid nonwoven nylon staple fibers and polyester fibers.

16. The filtration system of claim 11 , wherein the filter media includes oxidized polyacrylonitrile staple fibers, polyethylene terephthalate fibers, FR polyester fibers, bicomponent fibers and polyester fibers.

17. The filtration system of claim 11 , wherein the conduits include fiberglass.

18. The filtration system of claim 11 , wherein the accumulation layer includes secondary members that are not parallel with the conduits.

19. The filtration system of claim 11 , wherein at least some conduits extend from a first end of the accumulation layer to an opposed second end of the accumulation layer.

20. The filtration system of claim 11 , wherein the conduits define an acute angle with a cooking surface.

21. The filtration system of claim 11 , wherein the conduits include stainless steel.

22. The filtration system of claim 11 , wherein the conduits include aluminum.