Patent Publication Number: US-2019168141-A1

Title: Filter housing that accepts both single open end o-ring and double open end filter elements

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATION 
     This patent application claims the benefit of U.S. Provisional Patent Application No. 62/594,388, filed Dec. 4, 2017, the entire teachings and disclosure of which are incorporated herein by reference thereto. 
    
    
     FIELD OF THE INVENTION 
     This invention generally relates to filter systems and filter housings for mounting filter elements as well as portable filtering systems and methods of assembling the same. 
     BACKGROUND OF THE INVENTION 
     Filter systems are used to filter fluids to prevent damage or reduction in performance of downstream systems or to otherwise clean a fluid such as for drinking water. Many filter systems include a filter head to which one or more replaceable filter elements are mounted. Once the filter element is spent (e.g. a filter media thereof is full of impurities), the filter element can be removed and replaced without having to replace the entire filter system. 
     Some particular filter systems include filter housings that define a filter head and a filter bowl that attaches to the filter head. The filter head and filter bowl are both reusable. A replaceable filter element, also referred to as a filter cartridge, is located within the filter bowl during use. Many water filter designs use such a filter housing. Unfortunately, this can require the removal of the filter bowl during replacement. Removal of the entire bowl can be very problematic if the filter housing is not oriented with filter bowl mounted directly below the filter head and particularly if the filter bowl and filter head are oriented in a horizontal orientation. Once the bowl is removed all of the fluid will flow out of the filter housing. This problem can be further amplified if the fluid will flow into a location where it is undesirable to have fluid. 
     Further, there are numerous types of water filters that use different sealing interfaces to seal with a corresponding filter head. As such, if the wrong filter element is obtained to replace a spent filter element, the new filter element may not properly mate with the filter housing. 
     This issue can be further complicated if the filter system forms part of a portable filter system. Portable filter systems, such as for filtering water, may be used in very remote areas or during times of disaster when potable water is not readily available. Unfortunately, this can lead to the difficulty in finding the necessary replacement filter for a particular filter housing. 
     The present invention relates to improvements over the current state of the art. 
     BRIEF SUMMARY OF THE INVENTION 
     An embodiment of the invention provides a universal filter housing assembly that can be used with multiple different filter elements. More particularly, an implementation provides a filter housing assembly for use with a first type of filter element and a second type of filter element. The first type of filter element has a first sealing interface at a first end of a first tube of filter media. The second type of filter element has a second sealing interface at a first end of a second tube of filter media and has a third sealing interface at a second end of the second tube of filter media. The first sealing interface is configured differently than the second sealing interface. The filter housing assembly includes a housing body, a filter head and a cover member. The housing body extends axially between a first end and an open second end. The housing body defines a filter element mounting cavity. The filter head is at the first end of the housing body. The filter head includes first and second housing sealing interfaces. The first housing sealing interface is configured to sealingly mate with a first sealing interface when a filter element of the first type is located within the filter element mounting cavity. The second housing sealing interface is configured to sealingly mate with a second sealing interface when a filter element of the second type is located within the filter element mounting cavity. The cover member is removably attachable to the second end of the housing body. This allows for replacement of spent filter elements. The cover member includes a third housing sealing interface configured to sealingly mate with a third sealing interface when the filter element of the second type is located within the filter element mounting cavity. 
     In one embodiment, the first and second housing sealing interfaces are provided by a first annular wall. One of the first and second housing sealing interfaces is provided by a radially directed surface of the first annular wall. The other one of the first and second housing sealing interfaces is provided by an axially facing annular surface of the first annular wall. The axially facing annular surface axially faces the cover member. 
     In one embodiment, the third housing sealing interface is an axially facing surface provided by the cover member axially facing the first end. 
     In one embodiment, the axially facing surface is provided by an annular rib projecting axially towards the filter head. 
     In one embodiment, the first housing sealing interface is provided by the radially directed surface of the first annular wall and the radially directed surface of the first annular wall is a radially inward directed surface. 
     In one embodiment, a first port is provided, at least in part, by a second annular wall that is concentric with the first annular wall. The first and second annular walls defining an annular channel radially therebetween. The radially directed surface radially faces inward toward the second annular wall. 
     In one embodiment, the annular surface has an inner diameter of between about 1.7 and 1.8 inches. 
     In one embodiment, the axially facing annular surface of the first annular wall that provides the second housing sealing interface is dimensioned to contact in a sealing manner a second sealing interface of a filter element of the second type having an inner diameter of 1.25 and an outer diameter of 2.5 inches. 
     In one embodiment, the second housing sealing interface is provided by a tapered end portion of the first annular wall. 
     In one embodiment, the housing body provides a threaded region and a radially inward directed annular sealing surface having a first axial dimension. The cover member has an axially extending neck that is received axially within the second end of the housing body. The neck has a threaded region configured to engage the threaded region of the housing body. The neck carries a radially directed cover seal member. The radially directed cover seal member is radially engageable with the radially inward directed annular sealing surface along the first axial dimension such that the axial position of the cover member may be adjusted relative to the housing body to accommodate different length filter elements within the housing body with the radially inward directed annular sealing surface remaining in sealing engagement with the radially directed cover seal member. 
     In one embodiment, the axial position of the cover may be adjusted by at least 0.125 inches relative to the housing body with the radially inward directed annular sealing surface remaining in sealing engagement with the radially directed cover seal member. More preferably, the axial position is adjustable by at least 0.25 inches. 
     In one embodiment, the housing body is provided by an axially extending annular pipe extending between first and second ends and an annular collar member. The first end is adjacent the filter head and the second end of the annular pipe is attached to the annular collar member. The annular collar member defines the open second end of the housing body. The cover member removably attaches to the collar member. 
     In one embodiment, the cover member includes a closed end and an axially extending neck extending axially from the closed end. The axially extending neck extends axially through the open second end when the cover member is attached to the housing body. The closed end includes a handle sized for a user&#39;s hand to grip the cover member for attaching the cover member to or detaching the cover member from the housing body. The handle is defined in part by axially recessed pockets formed by the closed end. 
     In one embodiment, the housing body includes a radially extending projection defining an axial abutment. The radially extending projection and axial abutment are axially offset from the open second end toward the first end. 
     In one embodiment, the first and second housing sealing interfaces surround, at least part of, the first port. 
     In another embodiment, a filter apparatus for use with a filter element is provided. The apparatus includes a containment enclosure and a filter housing assembly located within the containment enclosure. The containment enclosure defines an enclosed volume defined at least in part by a first sidewall. The first sidewall including a first access opening. The containment enclosure also includes a dirty fluid inlet and a clean fluid outlet. The filter housing assembly includes an housing body, a filter head and a cover member. The housing body extends axially between a first end and an open second end. The housing body defines a filter element mounting cavity. The open second end cooperates with the first access opening such that the filter element mounting cavity is accessible from the exterior of the containment enclosure through the first access opening and the open second end. The filter head is at the first end of the housing body. The filter head includes a first port in fluid communication with the filter element mounting cavity and a second port in fluid communication with the filter element mounting cavity. One of the first and second ports is in operable fluid communication with the dirty fluid inlet and the other one of the first and second ports is in operable fluid communication with the clean fluid outlet. The cover member removably attaches to the second end of the housing body. The cover member closing all or a portion of the first access opening when it is attached to the housing body. The cover member therefore provides a portion of the exterior surface of the filter apparatus in use. 
     In one embodiment, the filter housing assembly is configured for use with a first type of filter element having a first sealing interface at a first end of a first tube of filter media and alternatively for use with a second type of filter element having a second sealing interface at a first end of a second tube of filter media and having a third sealing interface at a second end of the second tube of filter media. The first sealing interface is configured differently than the second sealing interface. The filter housing assembly further includes first and second housing sealing interfaces. The first housing sealing interface is configured to sealingly mate with a first sealing interface of the filter element when the filter element is of the first type and is located within the filter element mounting cavity. The second housing sealing interface is configured to sealingly mate with a second sealing interface of the filter element when the filter element is of the second type and is located within the filter element mounting cavity. The cover member further includes a third housing sealing interface configured to sealingly mate with a third sealing interface of the filter element when the filter element is of the second type and is located within the filter element mounting cavity. 
     In one embodiment, the housing body includes a radially extending projection defining an axial abutment that abuts an inner surface of the first sidewall surrounding the access opening. 
     In one embodiment, the radially extending projection and axial abutment are axially offset from the open second end toward the first end. A portion of the housing body axially between the axial abutment and the second end extends axially through the first access opening. 
     In one embodiment, the cover member includes an axially extending neck that extends axially through the open second end and the first access opening when the cover member is attached to the housing body. 
     In one embodiment, the housing body has a threaded region that engages a threaded region of the neck to secure the cover member to the housing body. The open second end has an inner diameter. The cover member has a maximum diameter that is smaller than the inner diameter of the second end. This allows the cover member to be receivable completely axially into the housing body through the second end. 
     In one embodiment, the cover member includes a closed end and an axially extending neck extending axially from the closed end. The axially extending neck extends axially through the open second end when the cover member is attached to the housing body. The closed end includes a handle sized for a user&#39;s hand to grip the cover member for attaching the cover member to or detaching the cover member from the housing body. The handle is defined in part by axially recessed pockets formed by the closed end. 
     In one embodiment, at least 80% of a volume defined by the filter head, filter housing body and the cover is located within the containment enclosure, and more preferably at least 85%, even more preferably at least 90% and even more preferably at least 95%. 
     In another embodiment, a method of mounting a filter element in a filter housing assembly is provided. The method includes inserting a filter element into a filter housing assembly as described above. The filter element is of either the first type or of the second type. The method including sealingly engaging the filter element to the filter head. This includes engaging the first sealing interface with the first housing sealing interface if the filter element is of the first type or engaging the second sealing interface with the second housing sealing interface if the filter element is of the second type. The method includes attaching the cover member to the housing body to close the second end of the housing body. 
     In one method, the method includes engaging the third housing sealing interface with the third sealing interface if the filter element is of the second type. This may occur when the cover member is mounted to the housing body. 
     In one method, the first housing sealing interface is left unused if the filter element is of the second type and the second housing sealing interface is left unused if the filter element is of the first type. 
     In one method, the filter housing assembly is located within a containment enclosure of a fluid filtering apparatus as outlined above. The step of inserting a filter element into the filter housing assembly includes passing the filter element through both the access opening and the open second end. Attaching the cover member causes the cover member to form part of the exterior of the containment enclosure. 
     Other aspects, objectives and advantages of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention and, together with the description, serve to explain the principles of the invention. In the drawings: 
         FIG. 1  is a filter system according to an embodiment of the invention; 
         FIG. 2  is a cross-sectional illustration of the filter system of  FIG. 1 ; 
         FIG. 3  is an exploded illustration of one of the filter housing assemblies of the filter system and one of the types of filter elements that may be used in the filter housing assembly; 
         FIG. 4  is an enlarged partial cross-section illustration of the filter housing assembly of  FIG. 3 ; 
         FIG. 5  is an enlarged partial cross-sectional illustration of the filter housing assembly and the filter element of the first type in  FIG. 3 ; 
         FIG. 6  is an enlarged partial cross-sectional illustration of the filter element of  FIG. 5  removed from the filter housing assembly; 
         FIG. 7  is a perspective illustration of the cover member of the filter housing assembly of  FIG. 3  and a partial illustration of one end of the filter element of  FIG. 3 ; 
         FIG. 8  is a perspective illustration of the cover member of  FIG. 7 ; 
         FIG. 9  is a cross-sectional illustration of a second type of filter element that can be installed into the filter housing assembly of  FIG. 4 ; 
         FIG. 10  is a cross-sectional illustration of the second type of filter element of  FIG. 9  installed in the filter housing assembly of  FIG. 4 ; 
         FIG. 11  is a perspective illustration of the cover member of the filter housing assembly of  FIG. 4  and a partial illustration of one end of the filter element of  FIG. 9 ; and 
         FIG. 12  is a simplified, cross-sectional illustration of a portable filtering apparatus incorporating a filter system of  FIG. 1  therein. 
     
    
    
     While the invention will be described in connection with certain preferred embodiments, there is no intent to limit it to those embodiments. On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention as defined by the appended claims. 
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  illustrates a filter system  100  according to an embodiment of the invention. The filter system  100  includes first and second filter housing assemblies  102 ,  104 . While a pair of filter housing assemblies is illustrated, other embodiments could incorporate more or less than two filter housing assemblies. The filter system  100  finds particular use in filtering water. 
     With additional reference to  FIG. 2 , the filter housing assemblies  102 ,  104  are substantially identical. The filter housing assemblies  102 ,  104  are configured to receive two different types of filter elements  106 ,  108  as will be described in more detail below. For illustrative purposes, the first filter housing assembly  102  has filter element  106  of a first type mounted therein while second filter housing assembly  104  has filter element  108  of a second type mounted therein. However, both filter housing assemblies  102 ,  104  are configured to cooperate with either filter element  106  or filter element  108 . This provides significant flexibility as a user can use either type of filter element and not worry if the correct type of element has been obtained. Further, while filter system  100  is illustrated using one each of the different types of filter elements (e.g. filter elements  106  and  108 ), in operation, the filter system  100  could use filter elements of the same type, e.g. both elements could be like filter element  106  or both elements could be like filter element  108 . Further, filter elements  106 ,  108  could be in the other filter housing assembly than as illustrated. 
     In this embodiment, the filter housing assemblies  102 ,  104  are connected in series with a connection pipe  109 . As such, fluid will flow in series through both filter elements  106 ,  108 . Simply for purposes of explanation, filter housing assembly  102  will be upstream of filter housing assembly  104  such that fluid first flows through filter housing  102  and then through filter housing  104 . However, the fluid flow could be reversed in other situations. 
     The following will be an explanation of the filter housing assemblies  102 ,  104 . Because the filter housing assemblies  102 ,  104  are identical, only filter housing assembly  102  will be explained. 
     With reference to  FIGS. 2-4 , filter housing assembly  102  includes a filter head  110  that provides an inlet port  112  and an outlet port  114 . 
     The filter housing assembly  102  includes a housing body  116  connected to the filter head  110 . The housing body  116  includes an annular axially extending pipe  118  and an annular collar  120  attached to the axially extending pipe  118 . The housing body  116  extends between opposed first and second ends  122 ,  124 . The first end is defined by the pipe  118  and the second end is defined by the collar  120 . The housing body  116  defines, at least in part, a filter element mounting cavity  126  that is in fluid communication with the inlet and outlet ports  112 ,  114 . When installed, the filter element  106  is mounted within the filter element mounting cavity  126  operably separating the inlet and outlet ports  112 ,  114 . 
     A cover member  128  removably attaches to the second end  124  of the housing body  116 , which may be referred to as an open end, to close the second end  124  and the filter element mounting cavity  126 . The cover member  128  carries a seal member  130  in the form of an o-ring that operably seals with a sealing surface  132 . In an embodiment, the filter element is entirely axially received by the filter housing assembly such that no portion of the filter element extends axially out of the open second end  124  when the cover member  128  is removed. 
     The filter housing assembly  102 , as noted above, is configured to work with filter elements of different types. As such and with additional reference to  FIG. 5 , the filter head  110  includes a first housing sealing interface  136  configured to sealingly mate with a first sealing interface  138  of the first filter element  106  when the first filter element  106  is located within the filter element mounting cavity  126 . 
     The first housing sealing interface  136  is provided by an annular wall  140 . In this embodiment, the annular wall  140  surrounds a second annular wall  142  that forms part of the inlet port  112 . As the first annular wall  140  is spaced radially outward from the second annular wall  142  a groove  143  is formed therebetween. Preferably, the first and second annular walls  140 ,  142  are concentric with one another. In other embodiments, the second annular wall  142  is not included and the first annular wall  140  directly surrounds a portion of the inlet port  112 . Again, port  112  could alternatively be an outlet port. 
     The first housing sealing interface  136  is provided by an axially facing annular surface  144  defined by a distal end of the annular wall  142 . This axially facing annular surface  144  faces the cover member  128  and will form an axial seal with the first sealing interface  138 . To increase the pressure between the first housing sealing interface  136  and first sealing interface  138 , the axially facing annular surface  144  is provided by a tapered end portion  146  of the first annular wall  140 . This end portion tapers towards the axially facing annular surface  144 . While being illustrated as generally flat, the axially facing annular surface  144  could be curved or terminate in a point depending on the implementation. 
     In an embodiment, the radial location of the first housing sealing interface  136  is such that it can axially engage a first sealing interface  138  of the filter element  106  that has an inner radial diameter of approximately 1.25 inches and an outer radial diameter of approximately 2.5 inches. 
     With reference to  FIGS. 5 and 6 , in the illustrated embodiment, the first filter element  106  includes an annular tube of filter media  148  that extends axially between first and second ends  150 ,  152  and that surrounds a central cavity  154 . First and second end caps  156 ,  158  are attached to the first and second ends  150 ,  152 , respectively. The end caps  156 ,  158  may be formed from any standard material such as for example metal, plastic or urethane. The end caps  156 ,  158  may be preformed or molded in place. The end caps  156 ,  158  could be adhesively adhered to the ends of the filter media  148 , the ends of the filter media  148  could be embedded into the end caps  156 ,  158 , the end caps  156 ,  158  could be molded directly to the ends of the filter media  148 . 
     In the illustrated embodiment, a seal member  160  that provides the first sealing interface  138  is attached to the first end cap  156 . The seal member  160  could alternatively be provided by the end cap  156  such as if the end cap  156  is formed by a urethane material and particularly if molded directly in place. In some embodiments, the first sealing interface  138  could simply be an end of the tube of filter media  148 , e.g. if a yarn filter media is used. The first sealing interface  138  is an annular axially facing surface  162  provided by the seal member  160 . This axially facing surface  162  will axially abut the axially facing annular surface  144  of the filter head  110 . The engagement between sealing interfaces  136 ,  138  prevents fluid bypass between the filter head  110  and filter element  106 . 
     The first and second end caps  156 ,  158  are or are substantially identical to one another such that the first filter element  106  can be installed with either end in engagement with the filter head  110 . 
     The first and second end caps  156 ,  158  are annular end caps that define openings  164 ,  166  that fluidly communicate with central cavity  154 . With both end caps  156 ,  158  being open end caps, the first filter element  106  may be referred to as a double open ended filter element. As illustrated in  FIG. 5 , the inlet port  112  is in fluid communication with the central cavity  154  through opening  164 . Further, a portion of second annular wall  142  extends axially into opening  164 . 
     Because the first and second end caps  156 ,  158  are open end caps, the end that is not engaged with the filter head  110  must be closed to force dirty fluid to flow through the filter media  148 . When a filter element of this type is mounted in the filter housing assembly  102 , the cover member  128  operably closes opening  166 . In a preferred embodiment, the cover member  128  can be entirely axially received within the housing body  116  (e.g. as illustrated in  FIG. 1 ). 
     With reference to  FIGS. 5-7 , the cover member  128  includes a second housing sealing interface  168  in the form of an axially facing surface that is provided by an annular axially projecting rib  170  that projects axially towards filter head  110 . The second housing sealing interface  168  is configured to sealingly mate with, e.g. axially engage, a second sealing interface  172  of the filter element  106  when a filer element of the first type is located within the filter element mounting cavity  126 . The second sealing interface  172  is identical to the first sealing interface  138  provided by seal member  160 . As such, a second seal member  174  is provided that defines an axially facing surface  176 . Again, this corresponds with the fact that the filter element  106  can be installed with either end in engagement with the filter head  110 . 
     The annular axially projecting rib  170  extends from an inner surface of an imperforate closed end  178  of the cover member  128 . Further, annular axially projecting rib  170  may have a tapered end portion that narrows towards the second housing sealing interface  172  similar to housing sealing interface  136  described above. 
     With reference to  FIG. 4 , the o-ring  130  is carried by an annular axially extending neck  180  of the cover member  128 . The neck extends axially relative to the closed end  178 . The neck  180  is sized to extend axially into the housing body  116  and particularly into the open second end  124  defined by collar  120 . 
     The neck  180  has an externally threaded region that cooperate with an internally threaded region of collar  120 . As noted above, o-ring  130  cooperates with sealing surface  132 . Preferably, the axial dimension D 1  of sealing surface  132  is greater than o-ring  130  such that o-ring  130  can seal with sealing surface  132  at varying axial locations. This allows the cover member  128  to be threaded into the housing body  116  to varying axial distances to compensate for variations in the axial length between filter elements. This is particularly beneficial if there are variations in the lengths between filter elements of the first type as sealing of the filter element  106  within the filter housing assembly  102  requires the filter element  106  to be axially compressed between the filter head  110  and cover  128  and particularly between first housing sealing interface  136  and second housing sealing interface  168  to prevent fluid bypass around the filter element  106 . In some embodiments, the axial dimension D 1  of the sealing surface  132  relative to the sealing member carried by the cover member  128  allows the axial location of the cover member  128  to vary by at least 0.125 inches, more preferably at least 0.25 inches, and even more preferably at least 0.375 inches while still permitting sealing engagement between sealing surface  132  and o-ring  130 . 
     With reference to  FIG. 6 , the filter element  106  may include inner and outer wrappers  182 ,  184  to help support the filter media  148  as fluid flows therethrough. 
     With reference to  FIG. 8 , the closed end  178  of the cover member  128  further defines a handle  186  sized for a user&#39;s hand to grip the cover member  128  and applying a torque to attach or detach the cover member  128  from the housing body  116 . The handle  186  is defined in part by axially recessed pockets  188  formed by the closed end  178 . 
     With reference to  FIGS. 9 and 10 , the second filter element  108  is the second type of filter element that may be used with filter housing assembly  102 . Instead of providing the double open ends and the axially directed sealing interfaces  138 ,  172 , second filter element  108  provides a third sealing interface  190  that cooperates with third housing sealing interface  192  when a filter element of the second type is mounted within the filter housing assembly  102 . 
     The third sealing interface  190  in this embodiment is a radially outward directed sealing interface provided by a pair of axially offset seal members in the form of o-rings  194 ,  196 . The third housing sealing interface  192  is provided by a radially inward directed annular surface  198  of the first annular wall  140  that, in the illustrated embodiment, radially faces the second annular wall  142 . Thus, the filter head  110  provides two different housing sealing interfaces to accommodate filter elements that have sealing interfaces that are configured differently from one another. The inner diameter of the housing sealing interface  192 , in some embodiments is between about 1.7 and 1.8 inches and is preferably between 1.75 and 1.77 inches. 
     The second filter element  108  includes a tube of filter media  200  extending axially between opposed first and second ends  202 ,  204 . First and second end caps  206 ,  208  are attached to ends  202 ,  204 , respectively. The first and second end caps  206 ,  208  may be similarly formed and attached to filter media  200  as outlined above for end caps  156 ,  158 . The first end cap  206  is an open end cap that includes opening  210  that provides access to a central cavity  212  of filter media  200 . The third housing sealing interface  192  surrounds opening  210 . 
     The second end cap  208  is different than the other end caps in that the second end cap  208  is a closed end cap that prevents fluid flow therethrough. As such, the second end cap  208  need not provide a sealing interface. While the second end cap  208  will not carry a sealing interface for sealingly cooperating with cover member  128 , the cover member  128  will typically axially abut the axially outer surface  214  of the second end cap  208  to axially and, in some embodiments, radially position the second filter element  108  within the filter housing assembly  102 . For example, the second end cap  208  may include an axially extending projection  216  that can radially locate on rib  170 . 
     The distal end of first annular wall  140  which provides the first housing sealing interface  136  may axially abut the first end cap  206  when the second filter element  208  is installed to axially locate the second filter element  108 . 
       FIG. 12  illustrates a portable filtering apparatus  300  that utilizes filter system  100 . The portable filtering apparatus  300  finds particular use as a portable water filtering apparatus in harsh environments. The portable filtering apparatus  300  can be used in remote locations for providing clean water. The portable filtering apparatus also finds use for providing clean water during disaster recovery efforts. 
     The portable filtering apparatus  300  includes a containment enclosure  302  that defines an enclosed volume  304 . In some embodiments, a fluid pump  306 , a source of power  308  (e.g. a battery and motor or gas powered engine) for powering the fluid pump  306  and the filter system  100  are located within the containment enclosure  302 . 
     The containment enclosure  302  includes one or more sidewalls that provide a plurality of access openings  310 ,  312 ,  314 ,  316  therethrough. In the illustrated embodiment, the first access opening  310  allows for dirty fluid to enter the enclosure  302 . The first access opening  310  is in fluid communication with the fluid pump  306  which is then in fluid communication with a dirty side of (e.g. dirty fluid port) first filter housing  102 . The second access opening  310  is in fluid communication with a clean side of (e.g. clean fluid port) second filter housing  104 . The third and fourth access openings  314 ,  316  cooperate with the open ends of the filter housings  102 ,  104  to allow for replacement of spent filter elements housed within the filter housings  102 ,  104 . 
     While filter housing  102  is not directly connected to second access opening  312 , it is operably in fluid communication with second access opening  312 . As such, the intervening structure of the second filter housing  104  shall not prevent the clean fluid port  114  of the filter head  110  from being considered to be in fluid communication with access opening  312 . This shall similarly be applicable to the dirty fluid port  112  and first access opening  310  in view of intervening pump  306 . 
     Preferably, the containment enclosure  302  is otherwise sealed to prevent damage to the components housed within the containment enclosure  302 . 
     With additional reference to  FIG. 4  and to reference to filter housing  102  for explanation purposes, collar  120  includes a radially outward extending projection  220 . The projection  220  defines an axially facing axial abutment  222 . This axial abutment  222  is axially offset from the open second end  124  of the housing body  116  towards the first end  122 . 
     The axial abutment  222  axially abuts an inner surface  320  of sidewall  322  that surrounds third access opening  314 . Thus, housing body  116  and particularly collar  120  can be flush mount to sidewall  322 . While not viewable in  FIG. 12 , the cover member  128  closes all or a portion of the third access opening  314  when it is attached to the housing body  116 . When attaching or detaching the cover member  128 , the cover member  128  and a least neck  180  extends axially through the third access opening  314 . 
     In the illustrated embodiment, an axially extending portion  230  of annular collar  120  that extends between axial abutment  222  and open end  124  extends through third access opening  314 . 
     While the filter system  102  is not entirely surrounded by containment enclosure  302 , substantially all of the volume of the filter system  102  is surrounded by the containment enclosure  302  and preferably at least 80% thereof is housed within the containment enclosure  302 , more preferably at least 85%, even more preferably at least 90% and even more preferably at least 95% of the volume is surrounded by the containment enclosure  302 . With this arrangement, the majority of the components of the system are housed within the containment enclosure  302  while substantially only the cover member  128  is exposed to the surrounding environment. This prevents damage to the system as well as prevents spillage of water into the containment enclosure  302  during maintenance intervals. 
     The portable filtering apparatus  300  of the illustrated embodiment includes a pair of wheels  330  for assisting in movement of the apparatus  300 . Further, the containment enclosure  302  may be formed from a plurality of components removably attached together to provide selective access to the interior. Additionally, to assist in mobility, the portable filtering apparatus  300  may include wheels, as illustrated schematically. 
     All references, including publications, patent applications, and patents cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein. 
     The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) is to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention. 
     Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.