Patent Application
20180207573
Embodiments of the present disclosure relate generally to apparatuses, systems and methods for filtration, and more particularly, to filtrations in ventilation and cooling systems, as well as to replaceable filters that are embedded in filtration systems.
Most ventilation systems include air filters, whose primary role is to capture suspended particles and prevent them from proceeding in an airstream. There is a large variety of filter types and brands, but they all operate on a similar principle where a permeable medium allows air to flow through, while particulate matter that is suspended in the air is captured within the medium. Many of these media are based on woven or non-woven fibers of various types and densities. Over the operating life of the filter, particulate matter accumulates in the medium, gradually degrading its permeability. Such filters typically require frequent replacement, which leads to recurring expenses of purchasing replacement filters, disposing the old filters and the time and effort associated with the frequent replacement. Furthermore, the filters' performance deteriorates as captured particulate matter builds up in the media.
Media filters are frequently configured as standard, easy-to-replace parts that are shaped and sized to fit the ventilation system into which they are inserted, or vice versa, ventilation systems are designed to accept a standard filter from among a group of widely accepted standard filter sizes. In particular, many filters are standardized to certain rectangular dimensions and thicknesses, allowing the operator to acquire replacement filters from any number of different manufacturers who produce such replacement filters to established dimensions and specifications.
Cyclonic separators have the capacity to remove and capture solid particles from an airstream, using a different mechanism than media filters. In cyclonic separators, air enters a cavity at a high velocity through a tangential inlet and in an orientation that is horizontal (relative), namely in a plane that is perpendicular (relative) to the vertical axis (relative) of the cavity. The airflow in the cavity forms a vortex and the resultant centrifugal forces push suspended particles towards the wall of the cavity. Air exits the cavity through a central axial outlet, and the particulate matter collects at the bottom of the cavity. Cyclonic separators in their conventional form are not suitable for use as a filter in ventilation systems for at least functional reasons, as well as for reasons of form, shape and size.
Embodiments of the present disclosure address the shortcomings of current filtration systems, in particular (and for example), current filters in use for ventilation systems. Accordingly, the embodiments of the present disclosure present apparatuses, systems and methods for filtration, and more particularly, to filtrations in ventilation and cooling systems, as well as to replaceable air filters (for example).
In some embodiments, a filter is provided (e.g., an air filter), which includes a plurality of cyclonic-element arrays each comprising a plurality of cyclonic-elements, and a plurality of individual airflow paths corresponding to the plurality individual of cyclone elements in each array.
Such embodiments may include one and/or another, several (various combinations), or all of the following clarifications, structure, and/or functionality (as the case may be), and thus, establish a multitude of other embodiments by the inclusion and various alternative combinations thereof:
In some embodiments, “cylindrically-symmetric” corresponds to any structure which includes a rotational or axial symmetry.
In some embodiments, a method for increasing the lifespan or a replacement cycle time of an air filtration system having a filter or a plurality of such filters is disclosed. The method comprises, replacing an original or an existing filter with a replacement filter according to any one of the filter embodiments disclosed herein (such as those described above); or, by arranging additional filters according to any one of the filter embodiments disclosed herein (such as those described above), adjacent to or upstream of a plurality of the existing filters of the air filtration system.
The principles and operations of the systems, apparatuses and methods according to some embodiments of the present disclosure may be better understood with reference to the drawings, and the following description. These drawings are given for illustrative purposes only and are not meant to be limiting.
The following detailed description provides details for some of the disclosed embodiments, particularly those with respect to filters, which include arrays of cyclonic elements. Such filters, according so some embodiments, are configured to prevent passage of gas/air through the filters except via paths that traverse from the cyclone elements—i.e., via tangential inlets, through the cyclonic elements, and exiting out concentric axial outlets.
Filter 130 is shown separately in
The filter frame or housing 140 of the filter defines a first surface (e.g., side, upstream side) through which air enters the filter 130, and a second surface (e.g., side, downstream side) through which air exits the filter 130. In some embodiments, these two surfaces are parallel (or approximately parallel), and can be (often) planar. In some embodiments, the filters 130 may be formed as a non-planar structure.
In some embodiments, filters 130 includes a permeable sheet of paper which may be pleated/folded in an accordion-like fashion to increase the amount of surface for exposure to an airstream. The filtration performance of the filters can be controlled by varying properties of the permeable sheet such as the pleating density, the paper type, etc., of the permeable sheet. The frame 140 can be formed of cardboard, plastic, metal, rubber, and/or any other suitable material. The frame 140 can support the medium along the edge. Further support may be provided by cross beams 150 or a rigid screen placed within the medium. These serve to keep the filter media in place and support and maintain the form and shape of the media in the filter 130. Other filter shapes may be utilized, including non-rectangular flat shapes, such as a circular disc, or a non-flat shape such as hollow cylindrical filters, which allow air to flow axially into the cylindrical space and radially through the medium.
In some embodiments, the frame 140 is supported by the cabinet 110, and held in a location and orientation such that the air flows through the filter 130 urged by the fan 120. The filter 130 and the cabinet 110 may be further configured so that the filter 130 can easily be removed and replaced by a similar, filter 130 as needed (e.g., a new filter). In a non-limiting example, a slot is configured in the cabinet 110 allowing the filters 130 to slide in and out on guides or rails that match the filter 130. In some embodiments, a hinged or removable lid or cover is configured to be opened and to allow filters 130 to be removed and replaced.
The filter 200 can include a rectangular shape (as an example embodiment), but can have any shape including irregular or regular (e.g., circular, square, etc.) shapes.
In some embodiments a thickness of the filter (defined, for example, as the average separation distance between the two opposite planar surfaces of the filter (e.g., Tin
In some embodiments, receptacles are provided and configured to receive particles separated from an airstream by the cyclone element 240. For example, as shown in
In some embodiments, the receptacle 260 may be positioned at an angle relative to the cylindrical axis of the cavity 246 (
In some embodiments, such as shown in
In some embodiments, the dense-packing of cyclonic elements 240 into a filter for use in custom or existing air treatment systems can be facilitated by the miniature size of the cyclonic elements 240. For example, the overall height of the entire cyclonic element 240 can range from 0.5 mm to 25 cm, from 1 mm to 20 cm, from 50 mm to 15 cm, from 500 mm to 15 cm, from 1 cm to 10 cm, from 5 cm to 10 cm, including values and subranges in between. Such small sizes allows for packing a large number of cyclonic elements into a portable filter that has a small footprint, facilitating the use of such filters in standard air cleaning systems. In some embodiments, the cyclonic elements 240 can be sized based on the size of the particles that are slated for removal from the airflow. For example, larger cyclonic separators are generally ineffective at separating fine particles, as the centrifugal force in such cyclones is insufficient to effectively sequester very fine or light particles. A larger centrifugal force to separate out even finer particles from an airstream may be attained by reducing the size of the each cyclonic element in the filter while maintaining a constant (or approximately constant) linear velocity for the airstream (since the centrifugal force is inversely proportional to the radius of curvature of the circular motion). Thus, in some embodiments, a large number of small cyclones may carry a comparable airstream as one larger cyclone, while producing much higher separation force and thus provide far superior filtration of fine particles, in some embodiments. With the cyclonic elements, and the filters containing such elements, as disclosed herein, particles with size (e.g., average radius) in the micron range (e.g., from 0.01 micron to 0.1 micron, from 0.1 micron to 1 micron, from 1 micron to 10 microns, exceeding 10 microns, including values and subranges therebetween, may be separated out from an airstream.
In some embodiments, the linear velocity of the airstream may be controlled using a fan 120 or a pressure differential, similar to that shown in
An extended operating lifetime is enabled, with some embodiments of the present disclosure, by having sufficiently large receptacles 260, which take a long time to fill. While the horizontal cross section (or footprint) of each receptacle 260 is limited by the neighboring cyclones and their respective receptacles 260, the vertical dimension, or depth, of the particle receptacles 260, can be made as large as necessary thereby increasing their volume and extending the usable service life of the filter as much as needed. Further, in some embodiments, a plurality of the receptacles may be configured as a combined unit that may be removable separate from the cyclonic cavities.
In the following non-limiting example, the filtration of outside air with relatively high pollution levels is described. Particulate matter (PM) is typically measured in micrograms per cubic meter (μg/m3) or nanograms per liter (ng/liter), which are the same units. An outdoor PM level of 100 is considered high, but not unusual, in some of the world's more polluted cities. In one embodiment of the cyclonic filter array, each cyclone has a footprint of 10 mm2 and under the intended operating conditions of static pressure of 0.25″ Water Gauge (WG) induced by a fan, it carries approximately 0.1 liters per minute. If the cyclone elements separate virtually all the PM and eject them to the receptacle, the rate of mass accumulation in the receptacle, Rm, would be:
R
m=0.1 liter/min×100 ng/liter=10 ng/min=600 ng/hour
In the maximum workload example of 24 hours, 365 days a year, namely 8,760 hours per year, the annual rate of mass accumulation in each receptacle is:
R
m=600 ng/hour×8760 hours/year=5.3 milligrams/year
In this example and under these conditions, for a 10 year operating life the particle receptacle has to have the capacity for 53 milligrams. The volume of this accumulation would depend on the density of the particles, but for particles that are approximately the density of water, 1 mg/mm3, that would imply 50 mm3 volume. The dust receptacle for a single cyclone has a footprint approximately matched to the cyclone element, 10 mm2, so it would need to be approximately 5 mm deep to provide for a 10 year lifetime.
In a further embodiment of this example, a heating, ventilation and air-conditioning (HVAC) replaceable filter would have a surface area in the range from 30-90 cm square, 40-80 cm square, 50-70 cm square, 60 cm square, including values and subranges therebetween, and a thickness that is in the range of from 10 mm to 50 mm, from 15 mm to 40 mm, from 20 mm to 30 mm, 25 mm, including values and subranges therebetween. The cyclonic cavity elements would be between 5 mm to 15 mm, between 7 mm to 13 mm, between 9 mm to 11 mm, 10 mm, including values and subranges therebetween, in height excluding the receptacle. A receptacle of between 10 20 mm can be attached while still maintaining a target thickness of under 25 mm, under 20 mm, under 15 mm, including values and subranges therebetween for the cyclone array sheet. This example can be utilized to calculate the required bin depth for other operating conditions and required lifetimes.
More generally, the depth of the receptacles can be made larger to accommodate more particle volume, or smaller to produce a thinner or lighter filter. In some embodiments, the receptacle depth can be between 1 mm to 100 mm, between 1 mm to 75 mm, between 1 mm to 50 mm, between 2 mm to 50 mm, between 2 mm to 30 mm, between 3 mm to 20 mm, between 5 mm to 18 mm, between 7 mm to 16 mm, between 9 mm to 14 mm, including values and subranges therebetween.
The filter may comprise more than one monolithic array. In some embodiments, a plurality of monolithic arrays can be combined into segments, to form a filter of the required form and dimensions. Multiple array segments can be attached in a number of configurations and using a number of techniques.
Multiple arrays of cyclonic elements can be combined in a co-planar configuration, for example, to form a larger, single planar filter. Such an approach allows a manufactured array module to be used to form a variety of different sizes of a planar filter. The arrays can be attached using any suitable technique, including but not limited to adhesives, clips, direct mechanical attachment, fasteners, or welding. The individual arrays may be attached to a common frame/housing 269, as shown in
Alternatively, multiple array segments can be combined in a non-coplanar configuration. For example, segments can be parallel to each other but not in the same plane. Such configuration can be seen as analogous to pleating of ordinary paper filters, where each array segment is analogous to a single pleat, as described herein.
The orientation of the filter may depend on the system in which it is placed. In general air flow at the surface of the array in a direction that is perpendicular to the array's geometric surface. In some filtration systems, a flat filter is placed in a horizontal orientation, where air flows vertically through the filter. In other cases, filters can be positioned in a vertical orientation where the airflow is horizontal. In other instances, filters are oriented in an angle with respect to the direction of gravity. The latter can be the case for any number of reasons. For example, the airflow direction required by the system may be at such an angle, or the filtration system may be mobile or portable and be required to operate as it is moved. Air filters in vehicles, vessels and aircraft may be such an example.
Yet in other cases, multiple filters are combined in a so-called V-bank or zigzag configuration 270, shown in
In another embodiment, shown in
In a configuration of parallel array stack at 90-degrees (or approximately thereto) to the filter, the width of the array in large part determines the thickness of the filter, which at least has to be as thick as the width W. The length of the array, L, on the other hand, can be larger as long as it does not exceed the length of the entire filter. There are several common standards for filter thickness, and in some embodiments, the array segments can be designed to meet such standards or similar standards. Among the common standards for low performance filters, a thickness T (
In this stack configuration, the stacking density is limited by the height of the cyclonic elements 240, including the receptacle 260. This presents a partial tradeoff between the overall number of elements 240, which can determine the total airflow through the filter, and the depth of the receptacles 260, which can affect the filter operating life as explained above.
A variation of the stack configuration can be also utilized when the intended filter orientation is horizontal and therefore parallel (or approximately parallel) to the array sheets/members. Such a configuration is shown in
The cyclonic element arrays can be made of any suitable material including plastics, metal, ceramics, glass, paper, fiber, composites and any other material that can be molded, shaped, stamped, machined, etched, carved, printed or otherwise formed into the required structure, including additive manufacturing such as 3-dimensional printing.
In some embodiments, the manufacture of an array is achieved in part by attaching a number of layers (formed separately) and, when attached in the designed manner, form the required cavities and inlets. In one embodiment, the layers are made of a plastic or polymer, such as, but not limited to, polyethylene, polypropylene, polystyrene, polycarbonate, PVC, PTFE or any other suitable plastic. Each layer can be formed using plastic manufacturing techniques including but not limited to injection molding, thermoforming or vacuum forming and/or additive manufacturing/3d-printing. Different layers can be formed using different processes. For example, one layer can be made with vacuum forming and attached to another layer made with injection molding. Different layers may be made of different materials and can be attached using adhesives, welding or simply a mechanical attachment that is secured by mating features in adjacent layers.
Arrays can be mass-produced in one or more standardized sizes, and a variety of filter sizes can be made from the mass produced array modules either by attaching a plurality of smaller sections or by cutting a larger sheet into smaller pieces that match the design of the filter required.
The dimensions and precise structure of the individual cyclonic elements can be modified to meet the requirements of different applications. Smaller diameter cavities will generally have better ability to capture finer particles.
While various inventive embodiments have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and/or structures for performing the function (or forming the structure) and/or obtaining the results and/or one or more of the advantages described herein, and each of such variations and/or modifications is deemed to be within the scope of the inventive embodiments described herein. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be an example and that the actual parameters, dimensions, materials, and/or configurations will depend upon the specific application or applications for which the inventive teachings is/are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific inventive embodiments described herein. It is therefore to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto; inventive embodiments may be practiced otherwise than as specifically described and claimed. Inventive embodiments of the present disclosure are directed to each individual feature, system, article, material, kit, and/or method described herein. In addition, any combination of two or more such features, systems, articles, materials, kits, and/or methods, if such features, systems, articles, materials, kits, and/or methods are not mutually inconsistent, is included within the inventive scope of the present disclosure and can be further embodiments. Some embodiments may be distinguishable from the prior art for specifically lacking one or more features/elements/functionality (i.e., claims directed to such embodiments may include negative limitations).
Also, various inventive concepts may be embodied as one or more methods, of which an example has been provided. The acts performed as part of the method may be ordered in any suitable way. Accordingly, embodiments may be constructed in which acts are performed in an order different than illustrated, which may include performing some acts simultaneously, even though shown as sequential acts in illustrative embodiments.
Any and all references to publications or other documents, including but not limited to, patents, patent applications, articles, webpages, books, etc., presented anywhere in the present application, are herein incorporated by reference in their entirety. Moreover, all definitions, as defined and used herein, should be understood to control over dictionary definitions, definitions in documents incorporated by reference, and/or ordinary meanings of the defined terms.
The indefinite articles “a” and “an,” as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean “at least one.”
The phrase “and/or,” as used herein in the specification and in the claims, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with “and/or” should be construed in the same fashion, i.e., “one or more” of the elements so conjoined. Other elements may optionally be present other than the elements specifically identified by the “and/or” clause, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, a reference to “A and/or B”, when used in conjunction with open-ended language such as “comprising” can refer, in one embodiment, to A only (optionally including elements other than B); in another embodiment, to B only (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc.
As used herein in the specification and in the claims, “or” should be understood to have the same meaning as “and/or” as defined above. For example, when separating items in a list, “or” or “and/or” shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as “only one of” or “exactly one of,” or, when used in the claims, “consisting of,” will refer to the inclusion of exactly one element of a number or list of elements. In general, the term “or” as used herein shall only be interpreted as indicating exclusive alternatives (i.e. “one or the other but not both”) when preceded by terms of exclusivity, such as “either,” “one of,” “only one of,” or “exactly one of” “Consisting essentially of,” when used in the claims, shall have its ordinary meaning as used in the field of patent law.
As used herein in the specification and in the claims, the phrase “at least one,” in reference to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements to which the phrase “at least one” refers, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, “at least one of A and B” (or, equivalently, “at least one of A or B,” or, equivalently “at least one of A and/or B”) can refer, in one embodiment, to at least one, optionally including more than one, A, with no B present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, with no A present (and optionally including elements other than A); in yet another embodiment, to at least one, optionally including more than one, A, and at least one, optionally including more than one, B (and optionally including other elements); etc.
In the claims, as well as in the specification above, all transitional phrases such as “comprising,” “including,” “carrying,” “having,” “containing,” “involving,” “holding,” “composed of,” and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases “consisting of” and “consisting essentially of” shall be closed or semi-closed transitional phrases, respectively, as set forth in the United States Patent Office Manual of Patent Examining Procedures, Section 2111.03.
This application claims priority to U.S. Provisional Patent Application No. 62/449,587, filed Jan. 23, 2017, entitled “Long Life Air Filter Based on Microfluidic Plastic Media”, the entire disclosure of which is incorporated by reference herein in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 62449587 | Jan 2017 | US |
