Source: https://patents.justia.com/patent/6843820
Timestamp: 2020-01-18 07:21:42
Document Index: 317467859

Matched Legal Cases: ['arts 15', 'arts 18', 'arts 15', 'arts 18', 'arts 15', 'arts 15', 'art 15', 'art 16', 'art 15', 'art 16', 'arts 15']

US Patent for Filter assembly Patent (Patent # 6,843,820 issued January 18, 2005) - Justia Patents Search
Justia Patents Unit Or Cohesive Sheet-like Media In Flow Line Or FrameUS Patent for Filter assembly Patent (Patent # 6,843,820)
A filter assembly with a frame and a filter element including a sheet of filter media with attachment strips at opposite ends. The frame positions the filter element with the filter media across a passageway in the frame and with the attachment strips along opposite end parts of a perimeter portion of the frame. Abutments extend along the perimeter portion between its end parts and along opposite edges of the filter material. Projections on the end parts are engaged in openings in the attachment strips and are spaced from the abutments such that the filter element can be mounted on the frame with either of the attachment strips engaged with the projections at either of the end parts while the filter element can only be mounted on the frame with an inlet surface of the sheet of filter material facing the same direction as a front surface of the frame.
The present invention generally relates to filter assemblies and, more particularly, to air filter assemblies that include reusable frames and replaceable filter material.
Many conventional residential heating and cooling systems include a disposable air filter assembly which includes a frame, a sheet of flexible filter material, and a filter material support structure such as a mesh screen that supports the filter material within the frame. When such a filter becomes dirty or clogged, the entire filter (including the frame and support structure) is discarded, even though only the filter material is no longer functional. This is wasteful and adds cost to such filters. Also, because such filters are rather bulky, they are often purchased as needed rather than being stored for future use. Thus, changing a filter can require purchasing a new filter which is not always convenient so that filter replacement can be delayed resulting in reduced efficiency of the system.
The present invention provides a filter assembly generally of the type described in U.S. patent application Ser. No. 10/172,575 which is further improved to help insure that the filter media is properly placed in the frame so that air will flow through the filter media in the proper direction.
The present invention will be further described with reference to the accompanying drawings wherein like reference numerals refer to like or corresponding parts throughout the several views, wherein:
FIG. 3 is an enlarged sectional view taken approximately along line 3—3 of FIG. 1;
FIG. 5 is an enlarged sectional view taken approximately along line 5—5 of FIG. 4;
FIG. 6 is an enlarged fragmentary sectional view taken approximately along line 6—6 of FIG. 1 with the filter element in a fully extended condition;
FIG. 7 is an enlarged fragmentary sectional view taken approximately along line 6—6 of FIG. 1 with the filter element in a more collapsed condition;
FIG. 9 is an enlarged fragmentary sectional view taken approximately along line 9—9 of FIG. 8; and
Referring now to the drawing, there is shown a filter assembly 10 according to the present invention. The filter assembly 10 includes a frame 11 of a stiff polymeric material having front and rear major surfaces 12 and 13. The frame 11 comprises a perimeter portion 14 having opposite first and second end parts 15 and 16 joined by opposite spaced side parts 18, and has a plurality of through passageways 17 between its front and rear surfaces 12 and 13 surrounded by its perimeter portion 14. The filter assembly 10 also includes a filter element 20 comprising a sheet 21 of flexible filter media having opposite major air inlet and outlet side surfaces 22 and 23, opposite ends 24 and 25, and opposite generally parallel first and second edges 26 and 27 that extend between its opposite ends 24 and 25. The sheet of filter media has end portions at its opposite ends 24 and 25 that extend at about a right angle to its opposite edges 26 and 27. To each of those end portions is attached an elongate attachment strip 28 that provides with those end portions structure having first and second through openings 34 and 35. The frame 11 includes structure for receiving and positioning the filter element 20 with the sheet 21 of filter media extending across the passageways 17, with the inlet surface 22 of the sheet 21 facing the same direction as the front surface 12 of the frame 11 and the outlet surface 23 of the sheet 21 facing the same directions as the rear surface 13 of the frame 11, and with the attachment strips 28 on the end portions of the sheet 21 of filter media extending along the opposite end parts 15 and 16 of the perimeter portion 14 of the frame 11. That structure on the frame 11 comprises first and second generally parallel spaced linear abutments 30 and 31 extending along the side parts 18 of the perimeter portion 14 between its end parts 15 and 16 and laying along the opposite edges 26 and 27 of the sheet 21 of filter material when the filter element 20 is in the frame 11, and spaced first and second projections 32 and 33 on each of the end parts 15 and 16 of the frame 11 that engage in the first and second openings 34 and 35 through different ones of the end portions and attachment strips 28 of the filter element 20 when the filter element 20 is in the frame 11. The first projection 32 at the first end part 15 is spaced the same first distance X from the first abutment 30 in a direction normal to the abutments 30 and 31 as the first projection 32 at the second end part 16 is spaced from the second abutment 31 in a direction normal to the abutments 30 and 31; and the second projection 33 at the first end part 15 is spaced the same second distance Y from the second abutment 31 in a direction normal to the abutments 30 and 31 as the second projection 33 at the second end part 16 is spaced from the first abutment 30 in a direction normal to the abutments 30 and 31. In the filter assembly 10 according to the present invention the first and second distances X and Y are different so that the patterns of the projections 32 and 33 and of the openings 34 and 35 are asymmetric. While the filter element 20 can be mounted on the frame 11 with either of the attachment strips 28 on the end portions of the sheet 21 of filter media engaged with the projections 32 and 33 (i.e., with the projections 32 and 33 in the opening 34 and 35 in the end portions and the attachment strips 28) at either of the end parts 15 or 16; the filter element 20 can only be mounted on the frame 11 with the inlet surface 22 of the sheet 21 adjacent or facing the same direction as the front surface 12 of the frame 11 and the outlet surface 23 of the sheet 21 adjacent or facing the same direction as the rear surface 13 of the frame 11. There are no openings in the attachment strips 28 that will receive the projections 32 and 33 when the inlet surface 22 of the sheet 21 of filter media faces the same direction as the rear surface 13 of the frame 11. This restricts the possibility that a user will place the sheet 21 of filter media in the frame 11 with its inlet surface 22 facing away from the direction that air is to flow through the frame 11, and helps to insure that the full filtering potential of the sheet 21 of filter media will be realized.
The filter assembly 10 can be used, for example, in air ducts associated with a furnace and/or air conditioning system. Accordingly, the frame 11 generally has a depth or thickness between its surfaces 12 and 13 of ½ inch to 5 inches, preferably between ¾ inch to 1¼ inches, and more preferably approximately 1 inch thick. The height of the frame 11 is generally between 5 inches and 24 inches, and preferably between 16 inches and 20 inches. The width of the frame is generally between 18 inches and 40 inches, and preferably between 20 inches and 30 inches.
While the sheet 21 of filter media may be of any filter media, it is preferred that the filter media is electro statically charged. The media can either be relatively stiff and self-supporting or relatively soft and non self-supporting. By “self-supporting” we mean that the sheet 21 of filter media, with or without a spacing structure, generally maintains its shape when subjected to an air stream. Generally, a stiff self-supporting media has a Gurley stiffness of greater than 50 milligrams for a sample size having a width of 2 inches and a length of 1.5 inches and preferably has a Gurley stiffness of greater than 100 milligrams for that sample size; and a soft non self-supporting media has a Gurley stiffness of less than 30 milligrams for that sample size. For media having stiffness values between these values, whether or not the media is self-supporting depends on the construction of the media, the shape of the sheet of filter media and on its use.
As an example, the sheet 21 could be made of the generally self-supporting filter media commercially identified as “ACCUAIR” 2.0 ounce per square yard filter media that is available from Kimberly Clark Corporation, Neenah, Wis. and has a Gurley stiffness of approximately 120 milligrams for a sample size having a width of 2 inches and a length of 1.5 inches. Also, the sheet 21 could be made of the non self-supporting filter media commercially identified as “FILTRETE”(™) GCB 35 that is available from 3M Company, St. Paul, Minn. and has a Gurley stiffness of approximately 15 milligrams for that sample size. That “FILTRETE”(™) filter media is a graduated density media in that it increases in density from a portion of the media that defines its air inlet surface and stops larger particulates in the air, toward portions of more closed media which collect smaller particulates than are collected at the air inlet surface. That “FILTRETE”(™) filter media also includes a reinforcing layer of a strong open scrim along its air outlet surface such as the reinforcing scrim commercially identified as “CLAF” that is available from Amoco Nisseki CLAF, Austell, Ga. Further details concerning that “FILTRETE”(™) filter medial are provided in U.S. Pat. No. 5,792,242 (Haskett), the content whereof is incorporated by reference herein. It is important for maximum efficiency of such graduated density filter media that the sheet 20 of filter media is positioned in the filter assembly 10 so that air will flow into the sheet 21 of filter media through its air inlet surface 22 and out of the sheet 21 of filter media through its opposite air outlet surface 23.
a stiff frame having front and rear major surfaces, comprising a perimeter portion defining the perimeters of said surfaces and having opposite first and second end parts, said frame having a through passageway between said front and rear surfaces surrounded by said perimeter portion;
a filter element comprising a sheet of flexible filter media having opposite major inlet and outlet side surfaces, opposite ends, and opposite generally parallel edges extending between said opposite ends, an end portion of said sheet at each of said ends extends at about a right angle to said opposite edges and has structure defining spaced first and second through openings; and
structure on said frame for receiving and positioning said filter element with said sheet of filter media extending across said passageway with said inlet surface of said sheet facing the same direction as said front surface of said frame and with said end portions of said filter element extending along said opposite end parts of said perimeter portion, said structure on said frame including first and second generally parallel spaced linear abutments extending along said perimeter portion between said end parts and laying along said opposite edges of said sheet of filter material, and spaced first and second projections on each of said end parts of said frame engaged in the first and second openings at a different one of the ends of said sheet of filter material;
said first projection at said first end part being spaced the same first distance from said first linear abutment in a direction normal to said abutments as said first projection at said second end part is spaced from said second linear abutment in a direction normal to said abutments, and said second projection at said first end part being spaced the same second distance from said second linear abutment in a direction normal to said abutments as said second projection at said second end is spaced from said first linear abutment in a direction normal to said abutments; and said first and second distances being different so that said filter element can be mounted on said frame with the structure at either of the ends of the sheet of filter material engaged with the projections at either of the end parts of the frame while the filter element can only be mounted on the frame with said inlet surface of said sheet facing the same direction as said front surface of said frame.
2. A filter assembly according to claim 1, wherein said frame comprises a base portion providing said structure on the frame for receiving and positioning said filter element, and a cover portion adapted to be moved relative to said base portion between an open position spaced from said structure for receiving and positioning said sheet of filter media to afford positioning said sheet of filter media on or removing said sheet of filter medial from said structure for receiving and positioning said sheet of filter media, and a closed position retaining said filter element on said structure for receiving and positioning said sheet of filter media.
the first opening at the first end of the sheet being spaced the same first distance from the first edge of said sheet in a direction normal to said edges as the first opening at the second end of the sheet is spaced from the second edge of said sheet in a direction normal to said edges, and the second opening at the first end of the sheet being spaced the same second distance from the second edge of said sheet in a direction normal to said edges as the second opening at the second end of the sheet is spaced from the first edge of said sheet in a direction normal to said edges, said first and second distances being different so that the filter element can be mounted on a frame with said structure at either of the ends of the sheet of filter media engaged with projections at corresponding positions on a frame with the projections in the openings at either of two opposite the end parts of the frame, while the filter element can only be mounted on the frame with the inlet surface of the sheet facing the same direction as a front surface of the frame.
11. A filter element according to claim 10, wherein said filter element includes two elongate attachment strips with each attachment strip attached along a different one of said end portions of said sheet of filter media, said attachment strips providing at least a portion of said structure defining said spaced first and second openings.
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U.S. Appl. No. 10/172,575, filed Jun. 14, 2002, Filter Assembly.
Patent number: 6843820
Patent Publication Number: 20040172928
Inventor: James O. Kubokawa (Saint Paul, MN)
Attorney: William L. Huebsch
Application Number: 10/379,069
Current U.S. Class: Unit Or Cohesive Sheet-like Media In Flow Line Or Frame (55/495); Edge Supporting Or Securing Means For Nonplanar Sheet Form Filter (e.g., Zigzag) (55/497); With Additional Transversely Arranged Members (55/499); Flexible Sheet Type Maintained In Nonplanar Configuration (55/500); With Additional Support Means Not Positively Engaged Or Joined To Media (e.g., Across Face Of Filter) (55/501); Media Within Joinable Or Separable Flow Line Sections (55/503); Zigzag, Corrugated, Or Conical (55/521); 55/DIG.0031