Abstract:
A filter for insertion into an air filter enclosure includes a pleated, collapsible filter having a flexible support member and a filter media layer, a top end cap and a bottom end cap. Side edges of the filter media layer cover the edges of the support member. The top end cap is configured for slidably mechanical attachment to a top portion of the enclosure. Weights and/or magnets are provided on the bottom end cap. The top end cap is guided into the top portion of the enclosure, after which the pleated media is released causing the bottom end cap to drop within the enclosure and magnetically attach itself to the bottom of the enclosure.

Description:
PRIORITY 
       [0001]    The present application is a continuation-in-part of copending U.S. Ser. No. 13/705,998 filed Dec. 5, 2012. 
     
    
     BACKGROUND 
       [0002]    Pleated filter media, such as collapsible pleated mechanical media (ESPM) filters, occupy substantially less space in their collapsed state, compared to equivalent cartridge configurations. Thus, they are easier to store and ship, and consequently have lower storage and shipping costs. However, collapsible filters are substantially less user-friendly than equivalent cartridge-style filters, which can be easily inserted into and removed from the filter enclosure with only minimal user interaction. In contrast, collapsible filters can require assembly by the end user before they are ready to be installed into the filter housing. For example, one such air cleaner includes an enclosure, upper and lower guide tracks, and a door. Effort is required to properly install the filter into the upper and lower guide tracks. Thus, there exists a need for a collapsible filter that can be installed into the filter enclosure with minimal effort by the end user. 
       SUMMARY OF THE INVENTION 
       [0003]    In accordance with the invention, an improved pleated, collapsible filter for an air cleaner is provided. The air cleaner includes a filter enclosure having a width W 1 , top and bottom guide tracks, at least the bottom track being comprised of a ferrous metal, wherein the air cleaner is configured to cause air to flow through the enclosure from an upstream to a downstream direction. The filter comprises a flexible metal support member having a first and second side edges, said support member having a width W 2  substantially equal to but less than W 1 . The filter media layer is connected to and covers at least one side of the support member and has an unfolded width W 3  greater than W 2 , such that the filter media when unfolded extends beyond the first and second side edges of the support member forming filter media skirts. The filter media skirts are folded over the respective first and second side edges of the support member so as to cover the side edges and form filter media cushions on the side edges of the filter, the filter with folded over skirts having a width W 4  that is substantially equal to W 1 . The filter is configured to be positioned in the enclosure with the support member downstream from the filter media with respect to the direction of airflow. A top end cap is connected to a top end portion of the filter, and is configured for slideable engagement into the top guide track of the filter enclosure. A bottom end cap is connected on an inner surface to a bottom end portion of the filter, and is weighted so that the bottom end cap falls to the bottom of the enclosure thereby expanding the pleated filter within the filter frame enclosure. Preferably, the bottom end cap also includes at least one magnet on an outer surface. The magnet is configured for magnetic attachment to the bottom guide track of the filter enclosure to further secure the bottom of the filter within the enclosure. 
         [0004]    A method of making a filter comprises providing a flexible support member having a width W 2  between side edges, providing a layer of filter media having a width W 3 , W 3  being greater than W 2 , attaching the support member to the filter media so that the filter material extends beyond the side edges of the support member forming filter media skirts, folding the filter media skirts over the sides edges of the support member to cover the side edges, attaching the skirts to the other side of the support member to form a composite filter media, and then pleating the composite filter media. Top and bottom end caps are formed, preferably by extrusion molding. The top end cap is configured to be slidably attached to a top guide track of a filter enclosure. The method further includes attaching magnets to an outer surface of the bottom end cap, and attaching the end members to opposite ends of the pleated composite filter media. 
         [0005]    A method of replacing a filter in a filter frame enclosure comprises providing a replacement filter comprised of a pleated, collapsible filter having top and bottom end caps, the bottom end cap being weighted and/or having at least one magnet. The method further comprises opening the filter frame enclosure, removing an old filter from the filter frame enclosure, and guiding the top end member only of the replacement filter into a top guide track of the filter frame enclosure. The method further includes sliding the replacement filter into the filter frame enclosure with the filter in at least a partially collapsed configuration, then releasing replacement filter allowing the bottom of the filter to drop within the filter frame enclosure. The weight of the bottom end cap holds the lower end of the filter in position within the enclosure. Further, the optional magnet on the bottom end cap magnetically attaches itself to a ferrous metal bottom member of the filter frame enclosure. 
         [0006]    Further features and advantages of the invention will become apparent from the following detailed description when read in reference to the drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is an isometric exploded view of a frame and a filter according to the invention. 
           [0008]      FIG. 2  is a longitudinal cross-sectional view of the frame and filter of  FIG. 1 . 
           [0009]      FIG. 3  is a partial cross-section of the filter taken along line  3 - 3  of  FIG. 2 . 
           [0010]      FIG. 4  is an enlarged detail of the frame and filter taken along line  4 - 4  of  FIG. 3 . 
           [0011]      FIG. 5A  is a plan view of a support member and the filter media layer. 
           [0012]      FIG. 5B  is a plan view of the filter media layer partially folded over the support member. 
           [0013]      FIG. 5C  is a plan view of the filter media layer folded over the support member. 
           [0014]      FIG. 6  is a partial cross-section of the filter taken along line  6 - 6  of  FIG. 2 . 
           [0015]      FIG. 7  is a bottom plan view of the bottom end cap. 
           [0016]      FIG. 8  is a partial cross-section view of an alternative bottom member similar to  FIG. 6 . 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    Referring to  FIG. 1 , an air cleaner is generally designated  10  and includes a frame enclosure  12  and a filter  14 . The frame enclosure  12  includes a top wall  16 , a bottom wall  18 , a rear wall  20 , and a reinforcement member  22 . The enclosure  12  has an upstream air-inlet opening  24  and a downstream air-outlet opening  26 . In addition, the enclosure  12  has a filter opening  28  that is opposite the rear wall  20 . The enclosure  12  can further include guide tracks  30  adjacent to the top wall  16  and the bottom wall  18  and that extend from at or near the rear wall  20  to at or near the filter opening  28 . The guide tracks and walls are conventionally formed of a ferrous metal, such as steel. A door  32  is attachable to the frame enclosure  12  to close the filter opening  28 . 
         [0018]    Filter  14  is preferably a pleated filter media such as a collapsible extended surface pleated mechanical media filter (ESPM) type such that the filter occupies substantially less space in its collapsed stated than in its expanded state. Typically, filter  14  is transported and sold in a collapsed state. At the time of installation, the filter is expanded, as shown in  FIG. 1 . The filter  14  is configured to be insertable into the frame enclosure  12  through the filter opening  28 . When inserted, the filter  14  extends between the top and bottom walls,  16  and  18  respectively, between the rear wall  20  and the filter opening  28 , and between the air-inlet opening  24  and the air-outlet opening  26 . Consequently, when the door  32  is closed, air can be directed to flow through the air cleaner  10  from the air-inlet opening  24 , through the filter  14 , and then exiting through the air outlet-opening  26 . 
         [0019]    As shown in  FIGS. 1-3 , filter  14  includes a filter media layer  34  and flexible support member  36 . As is well known in the art, the filter media may be made of non-woven natural or synthetic fibers capable of extracting impurities from the air. However, the filter media layer  34  can be made of other known or later-developed materials. 
         [0020]    The support member  36  is porous and flexible and is preferably fabricated from slit and expanded metal foil. However, the support member  36  could be made of plastic or other material. The support member  36  is more rigid than the filter media layer  34  and is preferably positioned on the downstream side of the filter media layer  34  in a direction of airflow as shown in  FIG. 3 . The filter support member  36  provides support to the filter media layer  34  to maintain a generally pleated shape of the filter  14 . As shown in  FIGS. 5A-5C , the filter support member  36  has side edges  40 ,  41 , a top edge  42 , a bottom edge  43 , a first side surface  44 , and a second side surface  46 . 
         [0021]    Referring to  FIGS. 3 and 6 , the filter  14  preferably includes a set of end caps  48 ,  49  at the top and bottom ends  50  and  52 , respectively, of the filter  14 . Each end cap is attached to the filter media layer  34 , the filter support member  36 , or both. Each end cap is configured to engage the guide tracks  30 , thereby securing the end caps and the filter  14  in the enclosure  12 . More specifically, top end cap  48  is configured to be aligned with and slidably engage top guide track  30  of frame  12  as shown in  FIG. 3 . 
         [0022]      FIGS. 6 and 7  illustrate a preferred bottom end cap  49 . End cap  49  includes a base member  65 , optional stiffening ribs  66 ,  67 , at least one, preferably plural, and more preferably four magnets  68 , and a weight  69 . A first pair of ribs  66  is provided on an inner side of the base member  65 , which aids in locating and attaching the bottom of the composite filter  34 ,  36 . A second pair of stiffening ribs  67  is provided on an outer side of side of the end cap, which aids in locating the magnets  68  during manufacture. The magnets are in between an abutted to ribs  67 . In one embodiment the end cap with ribs is extruded from plastic and the magnets  68  are attached in any manner, preferably with an adhesive backing. Alternatively, the bottom end cap  49  can be extruded of a magnetic material whereby the entire bottom end cap  49  is magnetic. The magnet(s) are configured to engage and magnetically attach to steel bottom guide members  64  of the frame enclosure  12 . If the filter enclosure does include guide members  64 , the magnets can be configured for attachment to any ferrous material bottom member of the enclosure. The end cap  49  further comprises a weight  69  attached to the base member  65 . The weight can be attached in any manner, such as with adhesive backing. The amount of weight added is that sufficient based on operating conditions to hold the bottom end cap down, either by weight alone or by the combination of weight and magnetic attachment. In one embodiment, a weight of at least 5 oz per lineal foot is added to a plastic base member, and in one preferred embodiment 5-8 oz per lineal foot is added. The weight may be comprised of any material, including metal, such as steel. Alternatively the bottom end cap  49  may be fabricated from a heavier material, such as steel, so that the design weight is thereby incorporated into the bottom end cap. As a result, the bottom end cap  49  is secured to the bottom of the enclosure  12  by the weight of the end cap, or by magnetic attachment, or by a combination thereof. 
         [0023]      FIG. 8  illustrates an alternative lower end or bottom hold-down. Unlike the  FIG. 6  embodiment, the alternative embodiment of  FIG. 8  does not include an end cap. Rather, an elongated hold-down member  70  is attached to the lower end of the filter media  34  and/or flexible support  36 . Attachment can be adhesive, or by forming a loop in the filter media or by any other means. Member  70  is preferably a metal rod, bar, pipe or other configuration, and has sufficient weight, e.g., at least 5 oz per lineal foot, to hold-down the bottom of the filter within the enclosure  12 . Optionally, hold-down member  70  can be magnetized so as to be magnetically attachable to the steel bottom of enclosure  12 . As a result, the bottom end of the filter is secured to the bottom of the enclosure  12  by the weight of the hold-down member, or by magnetic attachment, or by a combination thereof. 
         [0024]    The magnets and/or weighted end cap or hold-down member facilitate installation of the filter into to the frame enclosure  12 . Conventional filters, as shown for example in U.S. Pat. No. 8,157,881, require a user (home owner or HVAC maintenance personnel) to simultaneously align and insert both the top and bottom end caps into the respective top and bottom tracks of the frame enclosure, which can be cumbersome. With the subject filter embodiment, the user inserts only the top end cap  48  into top guide track  30 , while holding the filter in a compressed configuration. Once the top end cap is fully inserted in the top track, the user releases the filter allowing it to drop, expanding within the filter frame enclosure. The bottom of the filter is held down by gravity and/or by automatic magnetic attachment to the steel bottom of the filter enclosure. Similarly, replacing filters is easier. When removing an old filter from the frame the magnet attachment of the bottom member is easily released by the user. Accordingly, the weight and magnetic attachment of the bottom end cap facilitates filter installation and replacement. 
         [0025]      FIG. 2  shows the filter  14  installed in the enclosure  12 . The enclosure  12  has an interior width of W 1 , measured as the distance from the interior surface of the rear wall  20  to the interior surface of the door  32  when the door is closed. 
         [0026]    The filter  14  can optionally include one or more pleat spacer members  54  that extend between the end caps  48  and are connected to the end caps and the pleat edges  38 . The spacer member  54  functions to maintain uniform pleat spacing and provides structural support to the filter  14 . Multiple spacer members  54  can be provided on one or both sides of the filter  14 . 
         [0027]    Turning now to  FIGS. 5A-5C , the filter media layer  34  and the support member  36  are shown. In  FIG. 5A , the unpleated, flat support member  36  is shown attached to the flat, unpleated filter media layer  34 . The support member  36  has a width W 2  measured as the distance between side edges  40  and  41  of the filter support member  36 . The filter media layer  34  includes side edges  56  and has a width W 3  measured as the distance between the side edges of the filter media layer. The width W 3  is greater than W 2 . Preferably, the support member  36  is centered on the filter media layer  34  in the width direction. Preferably, the filter media layer  34  completely covers one side of the support member  36 . As shown in  FIG. 5A , the filter media layer  34  includes skirt portions  58 , which are portions of the filter media layer that extend beyond the side edges  40  and  41  of the support member  36 . 
         [0028]    As shown in  FIGS. 5B-5C , the skirt portions  58  of the filter media layer  34  are folded over the side edges  40 ,  41  of the support member  36 . The skirt portion  58  covers and is folded over the side edges  40 ,  41  to a portion of a second side  46  of the support member  36 . Preferably, the skirts  58  are folded over the side edges  40 ,  41  and are adhered or otherwise attached to the downstream surface of the support member  36 . However, it is not necessary that the skirts  58  be attached to the second side  46  of the support member  36 . A filter media cushion is thereby formed covering the side edges  40 ,  41  of the support member  36 . The filter media cushion  60  prevents the end user from coming into contact with the side edges  40 ,  41  of the support member  36 , which can be sharp and cause injury. The filter media cushion  60  also helps form an effective seal between the filter  14  and the enclosure  12 , as described below. 
         [0029]    The filter  14  has a finished width W 4  measured as the distance between the filter media cushions  60 . In some embodiments width W 4  is equal to or slightly greater than the width W 1  of the enclosure  12 , but in other embodiments W 4  may be equal to or slightly shorter than the width W 1  of the enclosure. Further, the finished width W 4  is greater or substantially equal to the width W 2  of the support member  36 . In other words: 
         [0000]      W 2 ≦W 1  
 
         [0000]      W 1 ≈W 4  
 
         [0000]      W 2 ≦W 4  
 
         [0030]    In embodiments where the width W 4  of the filter  14  is equal to or slightly greater than the width W 1  of the enclosure  12 , the filter  14  may closely fit within or be slightly compressed in a width direction in order to fit into the enclosure  12 . Specifically, cushions  60  represent the difference between W 2  and W 4 . In other words, the difference between the width W 4  and the width W 2  is the added dimension of the one or more filter media cushions  60 . As shown in  FIG. 4 , when the filter  14  is inserted into the enclosure  12 , the filter media cushion  60  forms a compression point  62  where the filter media cushion contacts the rear wall surface  20  and/or the door  32 . The support member  36  being more rigid than the filter media layer  34  is less likely to deform. Because of the seal formed at point  62 , air flowing through the ductwork is directed to pass through the fitter  14 . 
         [0031]    As shown in  FIG. 4 , the filter media layer  34  is folded over the side edges  40 ,  41  of the support member  36 . The filter media cushion  60  covers the side edges  40 ,  41  of the support member  36 . As the filter  14  is inserted into the enclosure  12 , the filter media cushion  60  will conform to the rear wall  20 , compressing the filter media at point  62 . This compression point  62  allows the filter  14  to form an effective seal with the enclosure  12 . 
         [0032]    In embodiments where the finished width W 4  of the filter  14  is equal to or slightly less that the width W 1  of the enclosure, the cushions will not be compressed, but an effective seal can still be formed as the gap if any between the filter and enclosure wall is minimal. 
         [0033]    It should be appreciated that the term “effective seal” encompasses exemplary embodiments where air flowing from the air-inlet opening  24  to the air-outlet opening  26  directed primarily through the filter  14 , rather than around it. It should be appreciated that the term “effective seal” does not necessarily mean that no air flows between around the filter media. 
         [0034]    While only certain embodiments have been set forth, alternative embodiments and various modifications will be apparent from the above description to those skilled in the art. These and other alternatives are considered equivalents and within the spirit of scope of the present invention.