Abstract:
A collapsible, protective cover may be used to enshroud a filter during shipping, storage, and installation. The cover protects the filter from dirt and other harmful debris which could contaminate the clean filter element contained within the filter. As the filter is inserted into a filter canister, the cover collapses around the filter and moves out of the way, allowing the filter to enter the canister.

Description:
[0001]     This application claims priority to U.S. provisional patent application Ser. No. 60/772,244 filed on Feb. 10, 2006. 
     
    
     TECHNICAL FIELD  
       [0002]     The field of this invention is the protection of filters against contamination.  
       BACKGROUND  
       [0003]     Canister filter systems are used extensively today on equipment such as internal combustion engines, construction and mining machinery, and many other types of industrial machinery. They are used to filter contaminants from fluid systems including fuel systems, lubrication oil systems, hydraulic fluid power systems, hydraulic fluid control systems, transmission fluid systems, air intake systems, and the like.  
         [0004]     A canister filter system typically includes i) a base which is often attached to the equipment, ii) a canister (sometimes called a housing), and iii) a filter which is removably positioned inside the canister. After the filter is positioned inside the canister, the canister is attached to the base with threads or other attachment means to form a sealed compartment around the filter. The canister, base, and filter cooperate to define fluid passages through which fluid is directed through the filter. The filter contains filter media which traps and collects contaminants as the fluid passes through it. The contaminants which are trapped and collected in the filter media as the fluid passes through may include dirt, water, soot, ash, metallic particles, and other harmful debris.  
         [0005]     Eventually these contaminants clog the filter media and reduce its effectiveness. Or other conditions can develop over time which also reduce the effectiveness of the filter media in removing contaminants. When this occurs, the filter media should be replaced or cleaned. Typically when the filter media is replaced, this is done by removing and replacing the entire filter with a new filter (i.e., typically the filter media is not removed from the filter and replaced, rather the whole filter is replaced with a new filter). But it is only the filter that need be replaced, while the canister, base, and any other components remain and are reused. The filter is designed to be conveniently replaced and readily disposable. The filter may be replaced periodically, according to the guidance of a maintenance schedule established for the particular application, to prevent the filter media from becoming too clogged.  
         [0006]     Other types of filter systems include, for example, spin-on filters that are common on most personal automobiles. The spin-on filter typically includes a cylindrical, hard metal casing enclosing filter media. The hard metal casing is joined to an axial end cap on one end. The end cap typically has a threaded port which mates with a threaded post on a filter base attached to the automobile&#39;s engine.  
         [0007]     Canister filter systems have many advantages over other filter systems such as spin-on filters. For example, maintaining a canister filter system may be less expensive than maintaining a comparable spin-on filter system. This is because the parts replaced during maintenance of a canister filter system can be less expensive than the parts replaced during maintenance of a spin-on filter system. When the filter media requires replacement in a canister filter system, only the filter needs to be removed and replaced with a new filter, whereas in a spin-on filter the entire assembly, including the hard metal casing and the axial end cap, must be removed and replaced. Also, disposal of the filter in a canister filter system may be simpler than disposal of a spin-on filter. This is because a canister filter can often be constructed from only two types of material: plastic and the filter media. This makes the filter relatively easy to dispose of or recycle. In contrast, a spin-on filter includes a metal casing and axial end cap in addition to the filter media and other components. The mix of materials in a spin-on filter can make disposal more complicated.  
         [0008]     Detracting from its many advantages, canister filter systems do have at least one disadvantage which has been a motivating force for the development of this invention. Filters in canister filter systems often leave the filter media exposed to the outside environment prior to installation. In contrast, spin-on filters are typically relatively protected by their hard, impervious outside casing, so there is less risk that the filter media will be contaminated by the outside environment prior to installation.  
         [0009]     Thus, the filter of a canister filter system may be susceptible to contamination prior to installation. If dirt or other debris contaminate the filter media prior to installation, then after installation these contaminants may make their way into and contaminate the fluid system that the filter was intended to protect. As a result, when replacing a filter in a canister filter system, the technician must take precautions to not contaminate the filter.  
         [0010]     Each filter typically includes a dirty side and a clean side. The unfiltered fluid enters the dirty side of the filter. The filtered fluid leaves the filter from the clean side and enters the fluid system that the filter system protects. If dirt or other contaminants are accidentally put on the dirty side of the filter, in most cases the filter media will trap and collect the dirt or other contaminants before they reach the clean side and enter the fluid system. However, if the dirt or other contaminants are put on the clean side, then they may be free to enter and contaminate the fluid system.  
         [0011]     In some canister filter systems, the clean side of the filter media is on the exterior surface of the filter, so the risk of contaminating the fluid system and causing damage is particularly acute if the filter is contaminated prior to installation.  
         [0012]     As components such as fuel pumps, hydraulic pumps, engines, etc. become more expensive, more high tech, and are made with tighter tolerances and specifications, it is increasingly important to protect these components against contamination because contamination may cause premature wear and even failure. If canister filter systems are to be used in such applications, then precautions must be taken to ensure that the filter is not contaminated.  
       SUMMARY OF THE INVENTION  
       [0013]     To help alleviate the risk of contamination of a filter prior to installation, a collapsible protective cover is placed over the filter. The cover is removed during installation of the filter. Other advantages and uses will be apparent to those of ordinary skill in this art. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]      FIGS. 1-11  each show schematically the same filter and protective cover.  
         [0015]      FIGS. 1   a  and  1   b  illustrate an end cover attached to a protective cover that surrounds a filter.  
         [0016]      FIGS. 2   a  and  2   b  illustrate the beginning of a process to open the end cover.  
         [0017]      FIGS. 3   a  and  3   b  illustrate the end cover opened.  
         [0018]      FIGS. 4   a  and  4   b  illustrate the end cover folded downward and out of the way to permit the filter to engage and enter a canister.  
         [0019]      FIG. 5  illustrates the filter positioned for entry into a canister schematically shown in cross section.  
         [0020]      FIG. 6  illustrates the filter beginning its entry into the canister and the protective cover beginning to collapse.  
         [0021]      FIG. 7  illustrates the filter continuing its entry into the canister with the protective cover continuing to collapse.  
         [0022]      FIG. 8  illustrates the filter further continuing its entry into the canister.  
         [0023]      FIG. 9  illustrates the filter almost completely inserted into the canister.  
         [0024]      FIG. 10  illustrates the filter completely inserted into the canister, and the protective cover removed therefrom.  
         [0025]      FIG. 11  illustrates the filter completely inserted into the canister, and the canister closed with an end cap schematically illustrated in cross section. 
     
    
     DETAILED DESCRIPTION  
       [0026]     The following is a detailed description of exemplary embodiments of the invention. The exemplary embodiments described herein and illustrated in the drawing figures are intended to teach the principles of the invention, enabling those of ordinary skill in this art to make and use the invention in many different environments and for many different applications. The exemplary embodiments should not be considered as a limiting description of the scope of patent protection. The scope of patent protection shall be defined by the appended claims.  
         [0027]     As discussed above, the ability to protect a filter from dirt and other debris during a filter change can be highly beneficial. To protect the filter, a protective covering may be installed on the filter during manufacturing or at a later stage. The protective covering protects the filter against debris and contamination before installation. During installation, the protective cover is simply and reliably removed in the manner fully described below.  
         [0028]     For purposes of illustration, the drawing figures include a filter for a canister filter system which is generally cylindrical in overall shape, as is known in the art, with a radial or circumferential outer surface, and an axial, circular bottom end and top end. The protective cover, too, is generally cylindrical in shape to match the filter, with at least a closed bottom end. The protective cover can be collapsed as the end of the protective cover is drawn or pulled down over the filter, to expose the filter, toward the other end of the protective cover.  
         [0029]     The top end of the protective cover may be closed with an end cover. The end cover is optional. The end cover is initially closed, and can then be opened immediately prior to installation to expose the top end of the filter for insertion into a canister opening.  FIGS. 1   a ,  1   b ,  2   a ,  2   b ,  3   a ,  3   b ,  4   a , and  4   b  illustrate a sequence of opening the optional end cover that may be used in conjunction with the protective cover.  
         [0030]     In  FIGS. 1   a  and  1   b , the filter  10  is covered by the collapsible, protective cover  20 . Protective cover  20  may be installed around the filter  10  at the time of manufacture of the filter, or at a later time. Protective cover  20  is intended to protect filter  10  from accidental contamination which may occur before the filter is installed. To be covered, the filter  10  need not be completely sealed from the outside environment. For example, a protective cover  20  which is open at a top end but still covers a majority of the filter element and protects it from contamination, should be considered as covering the filter  10 .  
         [0031]     Protective cover  20  in this embodiment includes the optional end cover  30 . End cover  30  is attached to protective cover  20  along a circumferential line at  30   a . End cover  30  includes a selectively closeable portion  31  which could be a zipper or clasp structure known for closing plastic bags and the like. When closeable portion  31  is closed, it forms, with protective cover  20  and end cover  30 , an enclosed chamber which protects dirt and debris from entering into the interior of filter  10  through its axial end  11 . End cover  30  may be folded and temporarily affixed to the protective cover  20  during packaging and shipping to keep it out of the way, as illustrated particularly in  FIG. 1   b . Then, while the technician is preparing the filter for insertion into the canister, the end cover can be extended into the shape shown particularly in  FIGS. 2   a  and  2   b . Then the technician can open the closeable portion  31 , as shown in  FIGS. 3   a  and  3   b . From this point on, the axial end  11  of the filter  10  is exposed to the outside environment. But prior to opening the closeable portion  31 , the axial end  11  was sealed and protected from contamination in the outside environment. In  FIGS. 4   a  and  4   b , the end cover  30  has been turned inside-out and folded back over the protective cover  20 , along line  30   a , to keep it out of the way.  
         [0032]     The end cover  30  is optional. The protective cover  20  could be constructed without end cover  30 , leaving the axial end  11  of the filter more exposed to the environment during shipping and storage. In some applications, this additional exposure may not present a risk. In other applications, a different system other than end cover  30  may be used to temporarily protect the axial end  11  of the filter from exposure. For example, protective cover  20  may be made to completely enclose the filter  10 , even around axial end  11 . Then, prior to installation, a technician would cut or tear away the portion of protective cover  20  surrounding axial end  11  to prepare for insertion into a canister.  
         [0033]      FIG. 5  shows the filter  10  positioned for insertion into a canister  40 . The canister  40  can be made according to any of several designs known to those of ordinary skill in this art, or could be made according to a new design for a particular application. The canister  40  may be attachable to a base member (not shown) which is typically attached to the engine or machinery. The canister  40  and base member cooperate to direct the flow of fluid through the installed filter  10 . The canister  40  would typically be constructed, for example, of metal or other hard polymer material. The filter  10 , protective cover  20 , and end cover  30  in  FIG. 5  are the same as those pictured in  FIGS. 4   a  and  4   b  and in the same position. However, the protective cover  20  could also be without end cover  30 .  
         [0034]     A ring  21  made of relatively rigid material, for example a nylon, ABS, or polypropylene or similar polymer material, is fixed to protective cover  20 . The ring  21  could be fixed to protective cover  20  with the aid of an adhesive, a clamp assembly, or any other method appropriate for a particular application. The ring  21  and protective cover  20  may be integrally formed of the same material with the ring  21  being relatively more rigid than protective cover  20  because it is made from a thicker section of the material. The ring could be a complete ring shape, or could be only a segment of a ring. The ring could be attached to the protective cover  20  around its entire periphery or circumference, or attached only a discrete locations. Different applications and types of material used will call for different constructions of ring  21 . The ring  21  could be sized so that its interior surface fits snugly against an O-ring  11   a  fitted around the circumference of filter  10 . O-ring  11   a  will prevent any debris from being able to pass between the ring  21  and axial end  11  and contaminate the circumferential exterior surface of filter  10 .  
         [0035]     During assembly of the filter  10  into canister  40 , ring  21  may be positioned adjacent a mating groove  42  formed circumferentially in an end  41  of canister  40 .  FIG. 6  shows the filter  10  during a first stage of insertion into the cavity  43  of the canister  40 . The groove  42  engages the ring  21  of protective cover  20  and helps hold ring  21  in position and prevents it and protective cover  20  from entering into the cavity  43 . As the filter  10  slides into the cavity  43 , the protective cover  20  partially collapses. The collapsing of the protective cover  20  can be made possible by constructing it from a thin sheet or film of material such as a polymer, or a metal such as aluminum or tin, or any other material appropriate for a particular application. The exact composition of the protective cover  20  is not critical, and suitable sheet or film material will be readily identifiable by those of ordinary skill in this art. The protective cover  20  could also be constructed with a more rigid material if the material is capable of folding, perhaps accordion style, to collapse upon itself.  
         [0036]     Alternatively, ring  21  may not be necessary. Protective cover  20  may include an open end portion with an edge in the place of ring  20 , which contacts the canister and causes the protective cover to collapse and compress.  
         [0037]      FIG. 7  shows the filter  10  continuing its entry into cavity  43 , and protective cover  20  continuing to collapse and compact. Because the material which makes protective cover  20  is not rigid, relatively little force is required to collapse it. Filter  10  can be pushed into cavity  43 , while protective cover  20  collapses and compacts, using only the pushing force from a technician&#39;s hand. As the protective cover  20  collapses, an increasing portion of filter  10  is outside of the protective cover  20 . However, this same portion is now positioned inside of the canister  40  so it is protected from debris.  
         [0038]      FIGS. 8 and 9  show an increasingly greater portion of filter  10  inside of the canister  40 , and an increasingly collapsed and compressed protective cover  20 .  
         [0039]     In  FIG. 10 , the filter is now fully inserted into the canister  40 . The O-ring  11   a  is seated against an opposite end  44  of the canister  40  and helps to define the fluid path that the fluid will take through the filter  10 . At or near the time when this occurs, the protective cover  20  can be slipped completely off of the filter  10 . A rigid second ring  22  may be provided on the bottom of the protective cover  20  and affixed thereto to help the bottom of protective cover  20  retain its shape and aid in its removal.  
         [0040]     In  FIG. 11 , the canister  40  has been closed with an end cap  43  and the installation of the filter  10  is complete. The used protective cover  20  may be used to enclose and protect a used filter which the new filter  10  replaced. For example, if the used filter were saturated with oil or other potentially hazardous fluid, the protective cover  20  could be used to prevent spills.  
       INDUSTRIAL APPLICABILITY  
       [0041]     The filter  10  is useful in filtering fluids for applications such as internal combustion engines, construction and mining machinery, and many other types of industrial machinery. Filter  10  may be used to filter contaminants from fluid systems including fuel systems, lubrication oil systems, hydraulic fluid power systems, hydraulic fluid control systems, transmission fluid systems, air intake systems, and the like.  
         [0042]     As discussed above, the ability to protect a filter from dirt and other debris during a filter change can be highly beneficial. To protect the filter  10 , a protective cover  20  may be installed on the filter  10  during manufacturing or at a later stage. The protective cover  20  protects the filter  10  against debris and contamination before and during installation. During the installation process, the protective cover is simply and reliably removed.