Abstract:
Improvements in a filter where the filter self-expands based upon increased pressure or vacuum in the filtering stream. The expandable filter is adaptable to filtering a wide variety of media including air used in HVAC units, gases that are used to filter impurities out of gases and for industrial applications. The expandable filter to maintain a constant pressure or vacuum in the plenum or filter. The filter self-expands as the pressure or vacuum increases and pushes, pulls or draws the filter into an elongated or heightened configuration. As the filter expands new filter material is exposed that was not previously exposed for filtering. Expansion doubles, triples, or further increases the filter collection surface area. The filter does not rely upon gravity and expands based upon the increase of pressure or vacuum in the plenum the filter can be arranged in a vertical or horizontal orientation.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of Provisional Application Ser. No. 61/584,712 filed Jan. 9, 2012 the entire contents of which is hereby expressly incorporated by reference herein. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable 
     THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT 
     Not Applicable 
     INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC 
     Not Applicable 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to improvements in a filter. More particularly, the present filter can automatically expands to provide new filter surface area to maintain uniform static pressure. The filter can be provided in square or round configurations. 
     2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98. 
     Filters are used in a variety of places including but not limited to HVAC units, vacuums, automobiles and other places. For most or all of the filters used in these applications the installed filter has a fixed amount of filter surface area. As the filter gets clogged the efficiency of the apparatus has to work harder to pull air through the filter and will stop filtering completely if no warning is in place. A number of patents and or publications have been made to address filter applications. Exemplary examples of patents and or publication that try to address this/these problem(s) are identified and discussed below. 
     U.S. Pat. No. 6,740,137 that issued on May 25, 2004 to James O. Kubakawa et al discloses a Collapsible Pleated Filter Element. The pleated filter element collapses as the pleats fold upon each other. While the high and low peaks and valleys provide for additional surface area that is not present in a flat filter, once the filter is placed within the filter holder the surface area of the filter remains unchanged. 
     U.S. Pat. No. 5,968,217 issued on Oct. 19, 1999 to Myron Stein et al, and U.S. Pat. No. 7,037,354 that issued on May 2, 2006 to Anthony Dimicelli both disclose expandable air filter systems. The expandable air filter systems are essentially an expandable filter mounted within an expandable frame. These patents allow for a frame to be compressed and set within a forced air unit and then expanded accommodating the required filter size. This type of product is particularly useful when the actual dimensions are not known. While the filter may be expandable upon installation, once the filter is installed the filtering surface area remains unchanged as the filter collects debris. 
     U.S. Pat. No. 6,152,980 issued on Nov. 28, 2000 to C. William Culwell discloses a size adjustable filter element. A pleated filter element is slid into a “C” frame with multiple metal reinforcing members. Once the filter element is installed the pleated filter is expanded to fill a plenum cross section. While this filter is expandable, the filter surface area does not change or adjust as the filer becomes clogged thereby allowing the pressure or vacuum to change as the filter clogs. 
     The waste particles that are released into the atmosphere from brake pads also creates multiple dilemmas. As force is applied to brake pads, the material on the pads is ground away. This material is known as brake dust and can be problematic for two main reasons. The first is that brake dust is highly corrosive and harmful to the environment. It is estimated that up to ninety percent of the worn away brake pad particles are released into the atmosphere. The dust particles created, which contains copper, brass, Kevlar, carbon fibers, metal filings, asbestos to name a few and acidic adhesive material, is extremely caustic to the environment. The second problem is that the remainder of the brake dust particles that are not released into the atmosphere is deposited on the vehicle wheels. The brake dust particles can be corrosive enough to burn through wheel coatings and leave expensive wheels damaged and unsightly. As a result, there have been a number of devices that have introduced dust shields or filter systems designed to reduce brake dust. These include U.S. Pat. Nos. 7,094,268, 4,484,667, 6,371,569, 6,173,821, 6,932,199, 6,155,650 and 5,772,286. U.S. Pat. No. 5,162,053 discloses a system that utilizes a suction mechanism along with a filter to capture brake dust. Finally, U.S. Pat. No. 6,592,642 discloses a device that utilizes an electrostatic charge to collect charged brake dust particles. 
     What is needed is filter that self-adjust in size to provide new filter material as the pressure or vacuum in changes. The proposed application provides a solution with a filter that in initially installed in a collapsed configuration with a first surface area of filter material. As the first filter surface area becomes clogged, the change in pressure or vacuum causes the filter to expand and expose a larger surface area of filter material. 
     BRIEF SUMMARY OF THE INVENTION 
     It is an object of the expandable filter to fit within an existing filter housing or frame. For most installations the ability of the filter to operate within an existing plenum or flow opening is important to ensure easy translation from an existing fixed flow cross section filter to a self-expanding filter. 
     It is an object of the expandable filter to filter air, gases or liquids. The expandable filter is adaptable to filtering a wide variety of media including but not limited to air used in HVAC units, gases that are used to filter impurities out of gases used for industrial applications and liquids from light oils, water and heavy lubricants or media. 
     It is an object of the expandable filter to maintain a constant pressure or vacuum in the plenum or filter. In a number of installations a change in the pressure or vacuum changes the amount of power that is required to pump or move the air, gas or liquids through the filter. As a finite filter becomes clogged the amount of energy to pump through a clogging filter increases. 
     It is another object of the expandable filter to self-expand. The filter self-expands as the pressure or vacuum increases and pushes, pulls or draws the filter into an elongated or heightened configuration. As the filter expands new filter material is exposed that was not previously exposed for filtering. The expansion can double, triple, quadruple or further increase the filter collection surface area and is only limited by the area that available for expansion. 
     It is another object of the expandable filter to include a warning system that notifies a user that the filter has fully expanded and needs replacement or servicing. The warning system can be as simple as exposing a whistle opening, depressing or releasing a mechanical contact or switch. The warning system ensures that the pressure or vacuum within the plenum can be maintained before the filter becomes completely clogged. 
     It is another object of the expandable filter to collect brake dust from a vehicle. The braking system is at least partially enclosed with a plenum or shroud. A blower draws the brake dust from the plenum through the expandable filter for collection of the brake dust. The shroud has a pair of opposed side walls, a pair of opposed shroud end openings and a shroud interior. Typically, a shroud is disposed on both sides of the rotor such that the distal side peripheries are covered by the shrouds. 
     It is still another object of the expandable filter to operate in a horizontal or vertical arrangement. Because the filter does not rely upon gravity and expands based upon the increase of pressure or vacuum in the plenum the filter can be arranged in a vertical or horizontal orientation. As the filter expands, detents or steps hold the expandable filter sequentially in each step. 
     Various objects, features, aspects, and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments of the invention, along with the accompanying drawings in which like numerals represent like components. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 
         FIG. 1A  shows the filter in an initial compressed mode. 
         FIG. 1B  shows the filter in an expanded mode. 
         FIG. 2A  shows a self-adjusting filter in a new compressed mode. 
         FIG. 2B  shows a self-adjusting filter in a semi-expanded mode. 
         FIG. 2C  shows a self-adjusting filter in an expanded mode. 
         FIG. 3  is a detailed view of an expanding chamber in a vertical orientation. 
         FIG. 4  shows a detail view of an expanding filter where the filter expands horizontally in both directions. 
         FIG. 5  shows a section of Type 2 Fixed filter material. 
         FIG. 6  shows a vertically expandable filter. 
         FIG. 7  shows the mathematical relationship of the surface area of a self-expanding filter. 
         FIG. 8  shows a perspective view of axle of a vehicle with the expanding filter collecting brake debris. 
         FIG. 9  shows a detailed perspective view of one side of a vehicle showing the internal feature of collecting brake debris. 
         FIG. 10  shows an embodiment of a brake debris collecting shroud on a disc brake rotor from  FIGS. 8 and 9 . 
         FIG. 11  shows a cross-section of the embodiment from  FIG. 10 . 
         FIG. 12  show a cross section of the brake dust collection shroud on a drum brake. 
         FIG. 13  show a control diagram illustrating features of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1A  shows the filter in an initial compressed mode. In the compressed mode the filter  10  may have a similar appearance a non-expanding filter. The filter  10  is sized and shaped to fit into an existing mounting frame. In the embodiment shown the filter is installed in an air return for a house HVAC unit where walls or studs  20  support  21  the bottom  30  of the air filter  10 . While this installation shows the filter  10  with the flow of air in a house, the flow can be gas, liquid or any other media that requires filtering. In addition to the media that is flowing, the installation is not limited to a house, and can be a vehicle air, oil, brake dust filter, gas filter or vehicle, home or industrial installation/application. 
     With a non-expandable filter, the surface area of the filter  20  is limited to the planar surface. Surface corrugations can add limited additional surface area, but the filter area remains fixed for the entire life of the filter. Basically unfiltered air  40  is drawn or pushed into the filter  10 . The dirty air  40  is collected  50  in the filter so clean air  42  exits the filter. As the filter  10  collects dirt  50  the amount of force to pass the air  40  through the filter increases. This increase requires the bower motor or pump to work harder. It is also contemplated that the edges of the filter can be square  35  or rounded  34  to improve air flow on and around the filter edges. As the pressure or vacuum of the air or media passing through the filter  10  increase the self-expanding filter opens from an initial dimension  31  in  FIG. 1  to an extended dimension  32  as shown in  FIG. 1B . 
       FIG. 1B  shows the filter in an expanded mode. When the filter  10  expands the height or depth  32  of the filter increases  33  to provide vertical walls  33  of expanded surface area for filtering. In many installations a pump or blower operates at optimal efficiency where there is an ideal static back pressure. Operating the pump or blower above or below the optimal back pressure can cause inefficiencies in the power consumption and or flow rate through the pump, blower, plenum or filter. In a non-expanding filter the back pressure can vary significantly from when the filter is clean to when the filter is dirty. In the self-expanding air filter, one or more sections of the air filter can expand  41  or open to maintain a more constant pressure or vacuum within flow stream to allow the pump or blower to operate at the optimum efficiency level. The expansion or opening provides new and unused filter area to be exposed thereby increasing the total filter/collection surface area. 
       FIG. 2A  shows a self-adjusting filter in a new compressed mode,  FIG. 2B  shows a self-adjusting filter in a semi-expanded mode, and  FIG. 2C  shows a self-adjusting filter in an expanded mode. From these figures the filter  11  is pleated or otherwise folded within a supporting cage that is supported  20 . In  FIG. 2A  the pleats  17  and mostly folded upon each other. Dirty air  40  enters into the exposed pleats and clean air  42  exits out of the filter. A central shaft  60  with detents  61  supports the collapsed filter. As the exposed filter material in  FIG. 2A  gets clogged the increased back pressure caused the filter to progressively open into  FIG. 2B . 
     A spring loaded ball  63  or other limiting mechanism rides in the detents  61  and limits the filter from completely opening in a single event. From  FIG. 2B  two pleats are opened to allow dirty air  40  to flow through the two open pleats. In this example at least six independent pleats  17  and or detents  61  are shown. While six sets are shown and described in this example, as few as two too many more than six pleats  17  or detents  61  are contemplated. In  FIG. 2C  the pressure or vacuum has completely opened the filter thereby exposing all of the pleats  11 . A stopping head  62  prevents further expansion of the filter and a mechanical switch  64  or whistle that notifies the consumer or user to replace the self-adjusting filter. 
       FIG. 3  is a detailed view of an expanding chamber in a vertical orientation. The filter  10  relies upon the pressure or vacuum of the system to open or expand the filter. Because the system pressure or vacuum is used the filter can be oriented in nearly any direction or orientation. The detents and spring loaded balls from the previous figures prevent the effects of gravity from overcoming the weight of the filter and close the filter with pressure or vacuum is not present. From the vertically oriented filter in  FIG. 3 , dirty air  40  enters into the filter  10  and clean air  42  exits the self-expanding filter. As the filter gets clogged the filter  10  can expand  41  to expose unused filter surface area. 
       FIG. 4  shows a detail view of an expanding filter  10  where the filter expands horizontally  41  in both directions. In this embodiment, air enters  40  into the outer radius of the filter. It is contemplated that within the filter, a dirt debris or particle generating mechanism or device may exist. One type of device can be a braking mechanism that generates brake dust that must be filtered to allow clean air  42  to exit. As the filter collects brake dust the filter can open  41  in one or both directions to expose additional collection media or filter. One such collection media or filter is shown and described with  FIG. 5 . 
       FIG. 5  shows a section of Type 2 fixed filter material  70 . The filter or media collection material in this example is 316 stainless steel with 150 micron  71  collection filter  70  but other equivalent or superior materials are contemplated. This size of filter porosity is ideal for collection of brake pad dust. This filter size allows for collections of the brake pad while allows for air to pass through the filter  70 . 
       FIG. 6  shows a vertically expandable filter. This embodiment shows a filter  10  with a vertical shield  15  that allows flow only through the exposed filter surface  11 . Dirty air  40  enters into the filter  10  and filtered air  42  exits the filter  10 . As the exposed filter area becomes clogged the filter  10  moves  41  to expose unused filter material. Bearings, balls or detents  63  provide steps to open  41  the filter in finite or infinite intervals  16  to expose unused filter surface. 
       FIG. 7  shows the mathematical relationship of the surface area of a self-expanding filter  10 . This embodiment provides some simple calculation examples to indicate the initial, steps and final amount of filtering. When this filter  10  is completely closed only the top surface  12  is used for filtering. A flange  83  prevents air from passing around the filter. If the top has a radius  81  of 5 inches then the top filter area is about 78 square inches. A single step  82  of one and a quarter inch will add over 39 square inches of filter surface area or about 50% more collection area. In the embodiment shown, seven expandable pleats are shown. These seven pleats  14  provide a total 80 of over 274 square inches of collection area for a total of 354 square inches while maintaining a fairly constant pressure or vacuum in the stream flow. This is 4.5 times greater area of collection. It is contemplated that any dimensions and pleat/detents can be changed to increase or decrease these ratios. 
       FIG. 8  shows a perspective view of axle of a vehicle with the expanding filter collecting brake debris and  FIG. 9  shows a detailed perspective view of one side of a vehicle showing the internal feature of collecting brake debris. From  FIG. 8  the tire(s)  90  of the vehicle are shown. While this embodiment shows a single blower with two expandable filters  10 , each rotor  112  of a vehicle can have its own expandable filter and blower  95  or a single expandable filter  10  and a single blower  9  can collect braking debris from more than two rotors  112 . From  FIG. 9  the rotor is predominantly surrounded by a shroud  120 . The rotor and shroud assembly is shown and described in more detail in  FIGS. 10 ,  11  and in the inventor&#39;s U.S. Pat. Nos. 7,963,376 and 8,191,691. Ducts  162  connect from the shroud  120  to the duct housing  92 . This embodiment shows the axle  91  extending under or around the duct housing  92 . In the preferred embodiment the blower  95  is operated when the brake switch is activated. While this is the preferred embodiment the blower can operate at all times or can operate at different speeds depending upon the braking condition of the vehicle. 
     Air  40  with brake debris moves from the shroud  120  through duct(s)  162 . In the embodiment shows an optional removable pre-filter tray  96  is shown that separates large debris such as rocks and other objects that initially enter the plenum  92  and collide with the pre-filter elements  94  from fine brake debris. A flange  83  prevents air from passing around the filter. As brake debris fills the expandable filter  10  the filter expands  41  to provide unused filter surface area as previously shown and described to provide a nearly constant vacuum or back-pressure within the collection plenum  92 . As the filter  10  becomes full and completely expands a stopping head  62  with a sensing switch  181  provides notification that the expandable filter  10  must be serviced. A removable cover  93  provides access to the expandable filter  10  and or the pre-filter tray  96 . 
     Filtered air  42  exits the expandable filter  10  and is drawn  43  through the ducting  92  by the blower  92  where the clean air  44  is blown into the atmosphere  45  or to another location. 
       FIG. 10  shows an embodiment of a brake debris collecting shroud on a disc brake  114  rotor and brake pad  116  or shoe from  FIGS. 8 and 9 .  FIG. 11  shows a cross-section of the embodiment from  FIG. 10 . These figures illustrate an embodiment wherein one of the shroud side walls  122  defines a pair of shroud wall openings. Disposed in fluid communication with each shroud wall opening is a duct  162  adapted to direct airflow out of the shroud interior and towards the brake pad or shoes. In this embodiment, a single shroud  120  not only covers at least one of the distal side peripheries of the rotor  112 , but also covers the available exposed distal edge periphery of the rotor  112 . In this design, the rotation of the rotor  112  also acts as an impeller to drive air through the shroud interior and ducts  162 . A filter  118  or pre filter may be placed within the shroud  120 . 
       FIG. 12  show a cross section of the brake dust collection shroud on a drum brake mounted within a tire rim  117 . Brake drum systems are commonly used in the rear axles  91  of trucks. These trucks can have multiple axles  91  with each axle having a drum on each tire. In this figure the axle  91  mounted on a drum  113  with the brake pad(s)  115  exerting braking forces on the interior of the brake drum  113 . Air is moved or drawn through the drum  113 , around the brake pad(s) or shoe(s)  115  and brake shoes or pads where the air moves brake dust through the shroud  120  and into the duct  162  for collection. 
       FIG. 13  illustrates a control scheme which can be used in the operation of the invention. In one aspect of this control scheme, when the braking action of the disc brake assembly  110  is initiated, electrical power flowing to the vehicle&#39;s brake lights  167  also provides power to blowers or fans  95  as shown and described in  FIG. 8 . 
     Also as indicated in  FIG. 13 , a water sensor  168  can be used to automatically shut off power to the blower or fan  95  when moisture is detected within the housing  128  and or  120 , and to indicate same to the motor vehicle operator. Once moisture is no longer detected within the housing  128  and or  120 , the blower or fan  95  are again allowed to turn on when braking action is initiated. Such water sensor  168  protects the blowers or fans  95  in the event of inadvertent total submersion. A sensor switch  180  indicates that the filter is full and requires cleaning or replacement. 
     Also as indicated in  FIG. 13 , a thermal sensor switch  170  can be used to detect excess heat within the housing  120  above a predetermined set temperature. The thermal sensor switch  170  can be adapted to automatically activate the brake pad fans or blower  95  to cool the disk brake assembly  110  even without having to initiate braking action. Once the temperature in the housing  120  falls below the set temperature, the brake pad fans or blower  95  are caused to stop and return to normal operation. 
     While the filters are shown and described in a variety of shapes and orientation, it is contemplated that the filter can be made in shapes from triangular, rectangular, square, octagonal, round and any variation that can be contemplated. 
     Thus, specific embodiments of an expandable filter have been disclosed. It should be apparent, however, to those skilled in the art that many more modifications besides those described are possible without departing from the inventive concepts herein. The inventive subject matter, therefore, is not to be restricted except in the spirit of the appended claims.