Abstract:
A filter cartridge has a cartridge top and a cartridge bottom interconnected by a cartridge sidewall. The cartridge top, the cartridge bottom and the cartridge sidewall enclose a filter media. An extension connectable to the cartridge bottom via threads is adjustable to fit the filter cartridge within a range of differently sized housings.

Description:
BACKGROUND 
       [0001]    1. Field of the Invention 
         [0002]    The present invention generally relates to filter media. More specifically, the present invention relates to a filter cartridge usable within a range of different filter housings requiring varying filter cartridge height mounting configurations. 
         [0003]    2. Description of Related Art 
         [0004]    Filter media is used in a wide range of processes such as the removal of solid contaminants from liquid process flows. A filter housing is dimensioned to receive filter media. Process connections to the filter housing direct a process flow through the filter media, whereby the filter media operates to filter the process flow to a pore size of the filter media. Because the filter media eventually becomes fouled by the trapped filtrand, the filter housings are adapted to allow easy exchange of the filter media. 
         [0005]    A typical filter housing has a filter basket or cage adapted to receive and or support the filter media. Although filter baskets are supplied with standardized diameters to allow a range of different filter media to reliably seal against the filter basket sidewall and or top surface(s), filter baskets of varied design and or manufacturers have significantly different depths between the top edge and the bottom. The filter basket may have different sidewall lengths and or different types of bottoms, such as a flat, conical or domed. 
         [0006]    Filter cartridges support filter media within a top, bottom and sidewall. Ongoing efforts to make filter cartridges cost efficient have led to minimization of structural material applied to the sidewalls, top and bottom. 
         [0007]    The routing of the process media into the filter cartridge at the top and out through the sidewalls and or bottom focuses hydraulic shocks occurring in the filter housing during process starts, stops and interruptions upon the bottom and or connection between the bottom and sidewalls. One way to prevent damage to the filter cartridge from hydraulic shock is to seat the filter cartridge against the filter basket bottom, whereby any hydraulic shock is transferred through the filter cartridge bottom to the filter basket bottom. Because of the varied range of heights between the filter basket top and the filter basket bottom of the various filter housings available, prior filter cartridges have been filter housing/filter basket specific, increasing the number of different models of filter cartridges a manufacturer has been required to manufacture and maintain an inventory of. Also, a user with different models of filter housings would have to ensure the proper filter cartridge is inserted into the corresponding filter housing and maintain an increased stock of multiple models of filter cartridges. Alternatively, filter cartridges have been designed for use without bottom support, which significantly increases manufacturing costs due to the increased top, bottom and sidewall supporting material required to make the filter cartridge strong enough to be resistant to failure from hydraulic shock, absent the support of the filter basket bottom. 
         [0008]    Competition within the filter cartridge industry has focused attention upon reliability, reduction of inventory requirements and reductions in manufacturing costs. 
         [0009]    Therefore, it is an object of the present invention to provide a method and apparatus that overcomes deficiencies in the prior art. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0010]    The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with a general description of the invention given above, and the detailed description of the embodiments given below, serve to explain the principles of the invention. 
           [0011]      FIG. 1  is a side cross sectional isometric view of a first exemplary embodiment of a filter cartridge according to the invention. 
           [0012]      FIG. 2  is a side cross sectional isometric view of a second exemplary embodiment of a filter cartridge according to the invention. 
           [0013]      FIG. 3  is a close-up side cross sectional isometric view of the bottom section of a third exemplary embodiment of a filter cartridge according to the invention. 
           [0014]      FIG. 4  is a side cross sectional isometric view of a filter housing with the filter cartridge of  FIG. 1  installed. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    A filter cartridge  10 , for example as shown in  FIG. 1 , supports the filter media  12  between an external support structure comprised of a cartridge top  14 , a cartridge sidewall  16  and a cartridge bottom  18 . To ensure that the process flow passes only through the filter media, the filter media  12  may be sealed against and or fused to the cartridge top  14  and the cartridge bottom  18 . One skilled in the art will appreciate that the filter media  12  and mounting configuration within the filter cartridge  10  may be selected from a wide range of materials for a desired chemical resistance/reaction, strength, porosity, surface area and or cost. 
         [0016]    The filter cartridge  10  has an adjustable height feature in the form of an extension  20  connected to the cartridge bottom  18  via threads  22 . By threading the extension  20  towards the cartridge bottom  18  and or away from the cartridge bottom  18 , a desired height of the filter cartridge  10  between a top of the cartridge top  14  and the extension bottom  24  is achieved. 
         [0017]    The extension  20  may be formed, for example, as a threaded screw, screwing into threads  22  of a threaded hole  26  formed in the cartridge bottom. To allow threading about a longitudinal axis of the filter cartridge  10 , the threaded hole  26  may be formed coaxial with the cartridge sidewall  16 . For failsafe operation of the filter cartridge  10 , the threaded hole  26  may be formed with a depth less than that of the cartridge bottom  18 . Thereby, the process flow can never pass through the threaded hole  26 , without first passing through the filter media  12 . Alternatively, as shown for example in  FIG. 2 , for maximum range of height adjustment, the threaded hole  26  may extend through the cartridge bottom to enable use of an extension  20  with an extended length, the threaded end of the extension  20  extending up into the filter cartridge  10  process flow area when a minimum height is desired. 
         [0018]    Alternatively, the extension  20  may be formed, for example as shown in  FIG. 3 , to thread upon threads  22  formed around an outer edge of the cartridge bottom  18  that mate with inward projecting threads  22  formed on an inner diameter upper shoulder of the extension  20 . 
         [0019]    The extension  20  may be formed from a cost effective material compatible with the process flow, such as a polymer, metal or ceramic. For maximum cost efficiency, the extension  20  may be formed from a durable material, such as stainless steel or the like, that may be repeatedly re-used by removal and re-installation as each used filter cartridge  10  is periodically exchanged for a new filter cartridge  10 . 
         [0020]    Used with a filter housing, for example as shown in  FIG. 4 , the filter cartridge  10  is inserted into the filter basket  32  until the extension bottom  24  bottoms against the filter basket  32 . Threading the extension  20  towards or away from the cartridge bottom  18  adjusts the height to a desired level, for example so that the cartridge top  14  seals against a desired portion of the filter basket top  34 . Sealing between the cartridge top  14  periphery and the filter basket  32  is demonstrated as an overhanging lip feature. 
         [0021]    However, one skilled in the art will appreciate that any number of different lip seals, flanges, biased edges, o-rings or other gaskets may be applied to provide a satisfactory seal. With the filter cartridge  10  properly seated into the filter basket  32 , a process flowpath is enabled. The process flowpath enters the filter housing  30 , passes through a process hole  38  in the filter cartridge top  14 , then through the filter media  12 , cartridge sidewall  16  and filter basket  32  before exiting the filter housing  30 . 
         [0022]    To ensure that the selected extension level does not change during process operation from vibration or the like, the extension bottom  24  may be formed with one or more protrusions  36  that key into perforations  36  of the filter basket  32 . The protrusion(s)  36  may be formed, for example, as a conical or pyramidal shape. 
         [0023]    The protrusion(s)  36  also enable an installation operation wherein the filter cartridge  10  is inserted into the filter basket  32  until it bottoms, and then the height is adjusted to a desired level, by threading the cartridge top  14  and thereby the entire supporting structure, for example to where the cartridge top  14  periphery seals against a corresponding section of the filter basket top  34 , the extension bottom  24  protrusion(s) keyed with the filter basket. 
         [0024]    One skilled in the art will appreciate that a filter cartridge according to the appended claims enables design and manufacture of filter cartridges for use in a range of different filter housings and or filter baskets. The adjustable height nature of the invention ensures that the bottom and or sidewall/bottom interconnection is supported by the filter basket bottom, reducing the strength requirements of the external support structure and in particular improving resistance against damage from hydraulic shock. Because the invention eliminates the need for manufacture, inventory and delivery of a significant number of different filter cartridge models, manufacturing and operating costs are significantly reduced. 
         [0000]    
       
         
               
             
               
               
             
           
               
                   
               
               
                 Table of Parts 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 10 
                 filter cartridge 
               
               
                 12 
                 filter media 
               
               
                 14 
                 top 
               
               
                 16 
                 sidewall 
               
               
                 18 
                 bottom 
               
               
                 20 
                 extension 
               
               
                 22 
                 threads 
               
               
                 24 
                 extension bottom 
               
               
                 26 
                 hole 
               
               
                 28 
                 shoulder 
               
               
                 30 
                 filter housing 
               
               
                 32 
                 filter basket 
               
               
                 34 
                 filter basket top 
               
               
                 36 
                 protrusion 
               
               
                 38 
                 process hole 
               
               
                   
               
             
          
         
       
     
         [0025]    Where in the foregoing description reference has been made to ratios, integers, materials, components or modules having known equivalents then such equivalents are herein incorporated as if individually set forth. 
         [0026]    While the present invention has been illustrated by the description of the embodiments thereof, and while the embodiments have been described in considerable detail, it is not the intention of the applicant to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, representative apparatus, methods, and illustrative examples shown and described. Accordingly, departures may be made from such details without departure from the spirit or scope of applicant&#39;s general inventive concept. Further, it is to be appreciated that improvements and/or modifications may be made thereto without departing from the scope or spirit of the present invention as defined by the following claims.