Patent Publication Number: US-9421485-B2

Title: Keyed system for connection of filter cartridge to filter holder

Description:
This application is a continuation of prior application Ser. No. 12/353,198, filed Jan. 13, 2009 and issuing on Oct. 22, 2013 at U.S. Pat. No. 8,562,830, which is a continuation of prior application Ser. No. 11/316,373, entitled “Keyed System For Connection of Filter Cartridge to Filter Holder”, filed on Dec. 20, 2005 and issuing on Jan. 13, 2009 as U.S. Pat. No. 7,476,314, which is a continuation-in-part of patent application Ser. No. 10/786,655, filed Feb. 24, 2004, and issued on Dec. 20, 2005 as U.S. Pat. No. 6,977,006, which is a continuation of patent application Ser. No. 09/928,666, filed Aug. 11, 2001, and issued on Feb. 24, 2004 as U.S. Pat. No. 6,695,891, which is a non-provisional application claiming priority of provisional patent application Ser. No. 60/224,632, filed Aug. 11, 2000, and also claims priority of prior, provisional patent application Ser. No. 60/272,221, filed Feb. 27, 2001, which are herein incorporated by this reference. Application Ser. No. 11/316,373, filed Dec. 20, 2005 is also a continuation-in-part of, and claims priority of, patent application Ser. No. 11/200,864, filed on Aug. 9, 2005, issued on Feb. 6, 2007 as U.S. Pat. No. 7,172,693 which is a continuation of patent application Ser. No. 10/372,040, filed Feb. 21, 2003, and issued as U.S. Pat. No. 6,926,826 on Aug. 9, 2005, which claims priority of provisional application 60/358,692, filed Feb. 21, 2002. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     This invention relates generally to fluid filters and filter cartridges and connections for the filters/cartridges to piping, valving, brackets, and other holders that cooperate with the filters/cartridges to make them operative in a flowing fluid system. More specifically, this invention relates to a system for “keying” a particular filter cartridge or filter to a particular cooperating filter head member or filter valve head. 
     SUMMARY OF THE INVENTION 
     The invention is an apparatus and method wherein a portion of a fluid cartridge-holder connection is structurally adapted so that only matched filter cartridges and holders can cooperate to allow installation of the filter cartridge in the holder and/or to form a fluid seal. In other words, each filter cartridge and holder combination or “set” is “keyed” so that only that particular filter cartridge design mates with that holder. According to the invention, there are created various cartridge-holder sets that each have the adaptation, but the adaptation is slightly offset for each set compared to the other sets. This way, a filter cartridge from one set may not be mixed with a cartridge from another set, and, therefore, a filter cartridge may not be installed on any but its own matching holder. 
     The adaptation preferably involves a varying location of a “key” protrusion and a “lock” recess combination, such as a tab-slot combination, typically with mating protrusion(s) and recess(es) being at a certain angle on a circumference for one cartridge-holder set and a mating protrusion(s) and recess(s) of a similar or identical shape being at a different angle on the circumference for another cartridge-holder set, and so on, for each similarly-shaped-but-differently-located-adaptation cartridge and holder set. In other words, the key protrusion and the lock recess are selectably locatable around cooperating perimeters of a filter cartridge and its holder. The key and lock structures (hereafter typically called “key protrusion” or “protrusion” and “lock recess” or “recess”, respectively) are preferably rigidly molded or otherwise permanently placed on/in the filter cartridge and holder, and so they are not considered moveable. They are, however, easily changed in the molding or other manufacturing process, that is, they are easily selectable by locating them at different angles/locations around a circumferential surface. 
     This system may include a plurality of sets of filters and holders, each set having a differently-located key and lock, wherein the key and lock of each set cooperate with each other to allow that filter to be installed in that holder, but that filter may not be installed in any other holder because the key or lock of that filter does not cooperate with the key or lock of the other holder. The term “key or lock” is used because the key protrusions may be placed on either the filter or the holder, and the lock recess may therefore be placed on the other item. 
     Thus, for example, a water or beverage filtration facility, experimental pilot plant, or other filter user may control filter cartridge placement accurately. A facility with multiple, different filtering applications may have filter cartridges on hand for each of the applications, but the cartridges will not be confused. For example, in a facility in which there are two different applications, many of the two different types of filter cartridges may be kept in stock and even may be mixed during storage or handling, but the filter cartridges will not be mixed when installed into the filter holders. This is because the filter holder and the filter cartridges for the first application are “keyed” differently than the filter holder and the filter cartridges for the second application. The terms “keying” or “keyed” refer generally to how and where the entire key system is located or accomplished, that is, to the positioning or style of either one or both of the cooperating key and lock structures, rather than specifically to only the location of the “key protrusion.” All the filter cartridges for the first application are keyed the same, that is, to match the first application holder, and all the filter cartridges for the second application are keyed the same, to match the second application holder. The keying for the first application and the keying for the second application does not need to be very different, but may be merely, for example, a slightly different angular position for the two protrusions and recesses. 
     Also, a filter manufacturer may control his product lines more carefully by using the invented key system. A manufacturer may key his holders and filter cartridges differently for different countries, different clients, different distributors, or for different time periods. This technique may be used to prevent unauthorized or low-quality copies of the manufacturer&#39;s filter cartridges from easily being made. With so many differently-keyed cartridges in the marketplace provided by the original manufacturer, the incentive to provide cheap, low quality copies will be minimized, due to the expense of retooling for each “key and lock” set. 
     The key system may include many different protrusion and recess structures, for example, tabs and slots (typically thin or elongated bar and channel structures or elongated dove-tail structures), bumps and holes (typically rounded or mounded structures with cooperating valleys or holes), wedges and wedge-shaped wells (typically circular section structures); and many other shapes. If a cartridge must be rotated on its longitudinal axis to be installed in a holder, leeway in the recess structure is supplied so that the protrusion may enter it while the cartridge still has a radial distance to turn. For example, in the case of an elongated filter that is pushed up into a filter head and then rotated on its axis to install its top end into a filter head, the recess comprises an axial portion for allowing axial insertion and a radial portion for radial rotation of the filter cartridge relative to the filter head. 
     The key system structures are located on surfaces of filter cartridges (or “filters”) and holders that contact each other during connection of the cartridge to the holder. This may be either surfaces that are involved in mainly providing a physical connection between the cartridge and holder or that also are involved in providing a fluid connection between the cartridge and the holder. 
     By “holder” is meant any of a variety of devices that receive and seal to a replaceable filter or filter cartridge. This can include a valve head (including valving to shut off piping when the cartridge is removed), a filter bracket that supports the cartridge and provides fluid flow conduits into and out of the cartridge, and other devices that contact and are in fluid communication with the cartridge. 
     By “filter” or “filter cartridge” is meant any container of filtration or treatment media that is connected to a holder for fluid communication with the holder to filter and/or treat the fluid brought into it via the holder. The keyed system invention may be applied to whatever structure of a filtering unit is inserted into the head or other holder, which might be a unitary filter or a filter cartridge encased partially in an outer housing below the level where the filter cartridge engages in the head. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a bottom perspective view of one embodiment of a filter head according to the invention, illustrating one embodiment of recesses for the invented key system. 
         FIG. 2  is a top perspective view of one embodiment of a filter cartridge according to the invention, illustrating an embodiment of protrusions for the invented key system cooperating with the recesses of the filter head of  FIG. 1 . 
         FIG. 3  is a bottom view of the filter head of  FIG. 1 , showing particularly the interior surfaces of the filter head. 
         FIG. 4  is a top view of the filter cartridge of  FIG. 2 . 
         FIG. 5  is a top perspective view of the filter cartridge and filter head of  FIGS. 1-4  connected together. 
         FIG. 6  is a top view of the cartridge and head combination of  FIG. 5 , with protrusions of the filter cartridge visible through apertures in the filter head. 
         FIG. 7  is a side cross-sectional view of the cartridge and head combination of  FIGS. 5 and 6 , viewed along the lines  7 - 7  in  FIG. 6 . 
         FIG. 8  is an enlarged detail view of a portion of the cross-sectional  FIG. 7 . 
         FIG. 9  is a top view of the filter head of  FIGS. 1, 3, 5-8 , with the filter cartridge removed. 
         FIG. 10  is a side cross-sectional view of the filter of  FIGS. 1, 3   5 - 9 , with the filter cartridge removed, viewed along the lines  10 - 10  in  FIG. 9 . 
         FIG. 11  is a side cross-sectional view of the filter of  FIGS. 1, 3   5 - 10 , with the filter cartridge removed, viewed along the lines  11 - 11  in  FIG. 9 . 
         FIG. 12  is a perspective view on an alternative embodiment of a filter holder, a bracket with keyed structure on connection tubes that connect to and fluidly seal to an alternative embodiment of filter cartridge. 
         FIG. 13  is a bottom, cross-sectional view of the filter holder of  FIG. 12 . 
         FIG. 14  is an end view of the filter holder of  FIGS. 12 and 13 . 
         FIG. 15  is a top view of the filter holder of  FIGS. 12-14 . 
         FIG. 16  is a detail view of Section “ 16 ” of  FIG. 15 , of the filter holder of  FIGS. 12-15 . 
         FIG. 17  is a front, cross-sectional view of the filter holder of  FIGS. 12-16 . 
         FIG. 18  is a front view of the filter holder of  FIGS. 12-17 . 
         FIG. 19  is a detail view of the inlet and outlet tubes of the filter holder of  FIGS. 12-18 , viewed as detail “ 19 ” of  FIG. 18 . 
         FIG. 20  is a partial side view of one embodiment of a filter cartridge, which is adapted to cooperate with the filter holder of  FIGS. 12-19 . 
         FIG. 21  is a partial side view of a filter cartridge of the type cooperating with the filter holder of  FIGS. 12-19 , but with an alternatively-angled key system structure. 
         FIG. 22  is a partial side view of a filter cartridge of the type cooperating with the filter holder of  FIGS. 12-19 , but with an alternatively-angled key system structure. 
         FIGS. 23 and 24  are details of two keyed male tubes and two keyed female tubes, respectively, wherein the male tubes may be provided on either a holder/bracket or a filter, and the female tubes may be provided on the other, cooperating item, as “key and lock” may be switched in position on the holder and filter. 
         FIG. 25  illustrates embodiments of female tubes on a holder/bracket, each tube having a slot. 
         FIG. 26  illustrates a side view of a filter embodiment with male tubes adapted for connection to the female tubes of  FIG. 25 . 
         FIG. 27  illustrates another view of the filter embodiment of  FIG. 26 , showing both male tubes on the top of the filter. 
         FIG. 28  is a partial view of one embodiment of a filter connected to one embodiment of a bracket, and with a fastening device being pivoted toward the filter top end to secure the filter to the bracket. 
         FIGS. 29 and 30  illustrate a filter and a bracket, respectively, that have a key system on one of the two tubular connectors, that is, on one pair of female and male tubes (shown not to scale). 
         FIGS. 31 and 32  illustrate another embodiment of a bracket and a filter, respectively, that have a key system on one of the two tubular connectors, that is, on one pair of female and male tubes (shown not to scale). 
         FIGS. 33 and 34  illustrate yet another embodiment of a filter and a bracket, respectively, that have a key system on one of the two tubular connectors, that is, on one pair of female and male tubes (shown not to scale), and wherein the key system includes two slots in the one female tube and two tabs extending from the one male tube. 
         FIG. 35  is a partial side view of an embodiment of a universal cartridge that is adapted to fit into all the filter holders/brackets that receive the differently-keyed cartridges shown in  FIGS. 20-22 . 
         FIG. 36  illustrates another embodiment of a universal cartridge that is adapted to fit into all the holders/brackets that receive the differently-keyed cartridges with 45 degree-spaced slots. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION 
     Referring to the Figures, there are shown several, but not the only embodiments of the invented key system.  FIGS. 1-11  illustrate a filter cartridge keyed shoulder embodiment of the invented keyed system.  FIGS. 12-22  illustrate a tubular connector embodiment of the invented keyed system. 
     The key system structures are located on surfaces of filter cartridges (or “filters”) and holders that contact each other during connection of the cartridge to the holder. This may be either surfaces that are involved in mainly providing a physical connection between the cartridge and holder or that also are involved in providing a fluid connection between the cartridge and the holder. 
     An example of key system structure on surfaces that are involved in providing physical connection, rather than fluid connection, is the key system structure on a shoulder of a filter cartridge that fits up into a valve-head holder. These areas are surfaces that do not normally liquid-seal to each other, but must clear each other if the end of the filter cartridge is to fit up inside the interior cavity of the valve-head. The top circumferential shoulder of the filter cartridge, and the inner surface of a valve-head, typically have areas that come in very close contact, but that are not directly involved in forming a liquid seal between the cartridge and the valve-head. These non-liquid-sealing areas may be keyed so that only a cartridge with a certain keyed surface shape may extend far enough up into the valve-head to be installed and locked into place. For example, tabs or other protrusions may be provided on the top surface of a filter spaced outward from an inlet-outlet neck, but external to the liquid-receiving passages. These filter cartridge protrusions may mate or “nest” in identically-located recesses on the inside surface of the valve-head that receives the cartridge, wherein the valve-head recesses are also external to the cartridge/valve-head liquid-receiving passages. 
     The keyed structure on the filter shoulder and the inner surface of the valve-head holder may be said to be located around the outer circumference of a shoulder of the top end of the filter cartridge and the cooperating or corresponding inner circumference of the valve-head cavity. Preferably the protruding “key” structure comprises a plurality of protrusions located within an arc of about 90 degrees or less around the circumference on which it lies, or more preferably within about 70 degrees or less. The cooperating recess structure is preferably located in the cavity surface, facing the filter cartridge shoulder, and, likewise, the same number of recesses are located within the same amount of circumference, preferably about 90 or less, and, more preferably, about 70 degrees or less. In this type of embodiment, the protruding and recessed structures do not form a liquid seal(s) between the filter cartridge and the valve-head, because other structure typically nearer the central axis of the filter cartridge and head serve that purpose. While this preferred key system locates the protrusions on the filter cartridge shoulder and the recesses on the head, the opposite is envisioned, wherein the protrusions may be inside the filter head and the recesses may be on the filter cartridge. 
     Another type of embodiment of the keyed system involves the structure that create a fluid seal between the filter cartridge and the holder, for example, the inlet and outlet ports of the filter cartridge and the respective, cooperating ports/tubes in the holder that convey liquid to and from the cartridge. In this type of embodiment, the protruding and recessed structures are located around the inner and outer circumference of a tubular connector, comprising a male tube and female receiver, that allow connection of the filter cartridge and the holder, wherein fluid is conducted through the tubular conductor(s) once the cartridge seals to the holder. An example of such a tubular connector key system includes one in which both the filter holder&#39;s inlet and outlet and both the filter cartridge&#39;s inlet and outlet are all tubular and are all keyed. Another example of such a tubular connector key system includes one in which only one of the filter holder&#39;s inlet and outlet, and only the corresponding one of the filter&#39;s inlet and outlet are keyed. 
     For example, a filter holder&#39;s inlet tube and an outlet tube (that direct flow to a cartridge and from the cartridge, respectively) each have an elongated axial tab that protrudes out from the outer cylindrical surface of the inlet tube and outlet tube at a chosen circumferential (also called “radial” or “angular” to imply non-axial) location or locations (that is, at different places on the circumference of the tube surfaces). Likewise, the inner cylindrical surfaces of the cartridge&#39;s cooperating female tubes (into which the holder inlet tube and outlet tube slide and seal) have channels or “slots” recessed into the surfaces at corresponding circumferential positions. This way, the holder inlet and outlet tubes slide into the cartridge ports, with the holder tabs sliding into the cartridge slots without significant resistance. Another cartridge with slots at a different circumferential location, on either one its ports, would not receive the holder tubes and, hence, could not be accidentally or incorrectly installed in that particular holder. In such a case, where the filter cartridge has two tubes (inlet and outlet ports), each of the ports could have a different slot circumferential location, as long as the holder is made to match. For example, the holder&#39;s inlet tube tab (and corresponding slot on the cartridge inlet port) could be at “straight up” at 0 degrees, while the tab on the holder&#39;s outlet tube (and corresponding slot on the cartridge outlet port) could be at 30 degrees offset relative to the inlet tabs and slots. With this type of system, for example, varying additional different cartridge and holder sets each by an additional 30 degrees, many different sets of keyed cartridges and cooperating holders may be made. Many other amounts besides 30 degrees could be chosen, but this amount of offset gives many different combinations while providing an offset easily seen and judged by a person. The inlet tabs and slots and the outlet tabs and slots may be varied independently, for example, many sets may have the inlet tabs and slots at zero (0) degrees, while the sets may have differently-positioned outlet tabs and slots. Or, sets may have inlet tabs and slots that vary from set to set by 10 degrees, while those sets&#39; outlet tabs and slots may vary by 15 degrees, for example. Or, the inlet tubular connector may have tab(s) and slot(s), while the outlet tubular connector has none, or the outlet tubular connector may have tab(s) and slot(s), while the inlet tubular connector has none. The mathematics of such a system suggest that practically an “endless” number of sets with different key system structures may be designed. 
     Other key system styles are envisioned, which allow generally flat or smooth surfaces of the filter cartridge and the holder that conventionally would contact each other to instead include a key system structure that ensures that only a particular type of filter cartridge may be installed in a particular holder. The key system structure of the various sets of filter cartridge and cooperating holders/valve-heads is typically invisible once the filter cartridge is installed. While this may result in differently-keyed filter cartridges having substantially similarly-shaped outer housings, a manufacturer may include indicia on the outer surface of the filter cartridge to indicate the different media or other filter differences. Also, a user may look at the key system structure as long as the filter cartridge is uninstalled. In any event, when the user attempts to install a cartridge, only properly-keyed cartridges can be installed into the holder/valve-head/manifold. 
     Keyed Filter Cartridge Shoulder ( FIGS. 1-11 ) 
     Referring to  FIGS. 1-11 , there is shown a preferred, but not the only embodiment, of the invented key system for a filter cartridge and a filter holder (hereafter also called a “filter head”). The preferred filter head  10  and cooperating filter cartridge  20  are illustrated separately in  FIGS. 1 and 2 , wherein one may see the “lock” recess structure included in the head  10  and the “key” protrusion structure included on the filter cartridge  20 . One may understand from this Description that embodiments of the invention also include a mirror-image arrangement, wherein “key” protrusions are on the head  10  and cooperating “lock” recesses are on the filter cartridge  20 . Or, a combination of the two arrangements may be used, wherein one or more sets of “lock” recesses are on the head and cooperating “key” protrusions are on the filter cartridge, plus one or more sets of protrusions on the head and cooperating recesses on the filter cartridge. 
     The preferred embodiment of filter head may be of the general type illustrated by the systems in U.S. Pat. No. 4,857,189 and Design 356,625, and, once the disclosure of the present invention is viewed, one of skill in the art will be able to construct a filter head that will be operative and operatively connect with a cooperating filter cartridge. Cartridges conventionally built for such filter head systems are shown in U.S. Pat. No. 4,857,189 and Design 356,625, for example. 
     The following discussion describes the preferred embodiment shown in the Figures, plus comments on some variations. One of average skill may envision alternative embodiments besides those mentioned that are within the scope of the invention. 
     In the preferred embodiment, the recess structure  22  in the head comprises an axial portion and a circumferential or “radial lock” portion. The axial portion preferably comprises a plurality of lock recesses  24  in the inner, lower surface of the head  10 , which might be called the “inside rim” of the filter head near the outer edge  23  of the head. The lock recesses  24  are separated by partition ridges  28 , which are spaced apart on, and protrude radially inward from, the surfaces of the lock recesses  24 . In combination with adjacent ridges  26 ′, partition ridges  28  define the circumferential length of each lock recess  24 . The radial lock portion  40  of the recess structure  22  comprises a circumferentially-extending recess, generally but not necessarily exactly, transverse to the axis of the head  10  and the filter  10  and located “above” ridges  26 . 
     In the preferred molded structure of the interior of the head  10 , ridges  26  and partition ridges  28  serve as obstacles for any improperly keyed filter cartridge to be inserted into the filter head  10 , and also, once the filter cartridge has been rotated on its axis, as obstacles for cartridge removal. Once the filter cartridge is inserted axially past the partition ridges  28 , by the key protrusions  34  sliding into the head through the lock recesses  24 , the filter cartridge may then be rotated so that the key protrusions  34  slide radially into the radial lock portion  40 . The filter cartridge is preferably operable only once the filter cartridge has been inserted axially to the full extent desired and the filter cartridge has been rotated to lock the cartridge into head, and preferably only a properly keyed filter cartridge can be installed. 
     The ridges  26  illustrated in  FIG. 1  are one example of many embodiments that help to define the lower boundary of the radial lock portion  40 , and that lock the filter cartridge from axial movement by retaining the key protrusions  34  in the lock portion  40 . The plurality of closely-spaced ridges  26  are preferred because they provide a barrier to axial cartridge movement while minimizing the amount of plastic needed in molding of the head  10 . Alternatively, each set of ridges  26  may have the space between the ridges  26  filled in, that is, replaced with a solid, continuous structure that protrudes, relative to the recessed lock portion  40 , inward toward the central axis of the head. Or, ridges  26  may be reduced in number or only occupy part of the space below the lock portion  40 . In other words, the structure located “below” the radial lock portion  40  near outer edge  23 , and serving as an obstacle to axial movement, may be of various shapes, size, and locations as long as one or more protrusion  33  on the filter cartridge is blocked by said structure. At a minimum, therefore, there should be inwardly-protruding structure below at least one or more key protrusions  34  when one or more of the key protrusions  34  in positioned in the lock portion  40 . Not all key protrusions need to be received/engaged in the lock portion, when the filter cartridge is “fully rotationally engaged,” which means the point at which the filter cartridge is rotated to the fullest extent allowed by a rotation stop in the lock portion. To limit rotation of the filter cartridge, specifically, to limit radial movement of the key protrusions  34  in the radial lock portion  40 , a rotation stop surface  41  is provided by extensions of ridges  26  or other structure. Thus, radial lock portions of various lengths will have a rotation, even in the case of closely adjacent sets of lock recesses to prevent rotation of the key protrusions past the radial lock portion and into the space above the adjacent set of lock recesses. 
     In the head  10  of the Figures, the lock recesses  24  are three in number and are of different circumferential lengths, specifically, three recesses of long, medium and short length relative to each other. Other numbers and lengths/sizes may be used, for example, two or four recesses, or more, and one long and two short recesses, or two long and two short recesses, or a plurality of recesses all of differing lengths. As in a lock and key system for a door latch, many different combinations may be devised, and are included in the invention. 
     While there may be only one set of recess structure and one cooperating set of protrusion structure, there are preferably more. Preferably, there are a plurality of sets of recess structure in the filter head, and most preferably, there are two sets of lock recesses  24 , each with its connected radial lock portion  40 . Preferably, therefore, the cooperating protrusion structure  33  number the same as the recess structure. 
     Referring to  FIGS. 3 and 4 , one may see that the circumferential distances of greatest interest may be described as:
         D, which is the circumferential length of the preferred recesses and the preferred cooperating key protrusions  34 ;   B, which is the distance between the sets of lock recesses or between the sets of cooperating key protrusions  34 , wherein B includes the radial lock portion  40  of the recess structure, wherein lock portion  40  may exist in the range of only a small part of distance B to substantially all of distance B except for a small radial rotation stop; and   T, which is the total distance between the “start” of one set of lock recesses or cooperating protrusions and the “start” of the adjacent set.
 
The absolute lengths of D, T, and B, and the lengths of D, T, and B relative to each other, may be varied. In the example of two sets of recess structure (and therefore the two sets of cooperating protrusion structure) each of the two sets may have different D lengths.
       

     In  FIG. 1 , the first set of two recesses is clearly shown, and the second set of recesses, located about 180 degrees (distance T) from the first set, is located at position  25  on  FIG. 1 . Thus, these two sets of recesses shown in the Figures are generally diametrically opposed, with the axial portion (lock recesses  24 ) taking up 70 degrees (distance D) and the radial lock portion  40  taking up about 70 degrees of the 110 degrees (distance B) which extends between the two sets of lock recesses  24 . This results in each part of a recess structure  22  being 180 degrees away from the corresponding part of the other recess structure, and the two recess structures  22  being spaced evenly around the entire 360 degrees. 
     Preferably, the lock portion is as long as the entire length of the key protrusions, however, this is not always necessarily the case. The recess structures  22  may be closer together (distance T) than 180 degrees, for example, with two identically-constructed or differently-constructed recess structures spaced 90 degrees (distance T), for example, in which case the lock recesses  24  might take up about 70 degrees of that 90 degrees, leaving up to slightly less than 20 degrees (20 degrees minus enough distance for a small rotation stop) for the radial lock portion  40 . This would be an example of an embodiment in which the radial lock portion is not as circumferentially long as the circumferential length of the axial portion. In such an embodiment, only some of the key protrusions  34  (or part of a key protrusion), would slide radially into (“be engaged in”) the lock portion, while some of the key protrusions  34  (or part of a key protrusion) would not be received (“not engaged”) in the lock portion; this would be sufficient, although not preferred, for locking the cartridge in the head. In the case of the lock portion being shorter in length than the total length of the key protrusions and a key protrusion(s) being unengaged in the lock portion, one or more protrusions or a part of a protrusion, in effect, would hang over the recesses. In such a case, the unengaged key protrusion(s) might still be supported by one or more ridges  28 . As long as some of the key protrusion(s) is/are engaged in the lock portion, the filter cartridge is engaged in the head, until the filter cartridge is rotated in reverse to an unlock point, that is, to a point where all necessary key protrusions slide can slide down through the recesses. 
     Another example would be to have the two recess structures within only a portion of the circumference of the head  10 , for example, within 180 degrees (for two recess structures where T=90 degree) or 270 degrees (for two recess structures where T=135 degrees). 
     Preferably, the recesses in each set of recesses are all contained within 90 degrees or less (distance D) or, more preferably, within 70 degrees or less (distance D). Especially preferred embodiments have recesses (and likewise cooperating protrusions) from a maximum of 70 degrees down to a minimum of 30 degrees on the circumference of the inner rim of the filter head. Less than 30 is also possible, but is less preferred. In  FIG. 1 , the first set of recesses is within about 70 degrees (“D” in  FIGS. 3 and 4 ). 
     Distance B may be within a wide range of lengths. For example, preferably, but not necessarily, B may be up to about 150 degrees (B equals 150 degrees when, for example, D is 30 degrees and T is 180 degrees) and down to about 30 degrees (B equals 30 degrees when, for example, D is 70 degrees and T is 100 degrees; or B equals 30 degrees when, for example, D is 30 degrees and T is 60 degrees). Other B distances may be outside the range of 30-150 degrees, particularly when B is very large (greater than 150 degrees) because D is very small (less than 30 degrees) or when B is very small (less than 30 degrees) because the two sets of recesses are very close together. In the case where B is very small, one would expect many of such embodiments to have radial lock portions only a fraction of the length of D, that is, only part of the key protrusions would fit into the radial lock portion before hitting a rotation stop in the radial lock portion. 
     Also shown in  FIG. 4  are lengths  134 ,  134 ′,  134 ″ of the key protrusions (which preferably equate to very slightly less than the lengths of the matching lock recesses  24 ), and the lengths of spaces  128 ,  128 ′ between the protrusions (which preferably equate to very slightly more than the lengths of the matching ridges  28 ). Preferably, but not necessarily, the lengths  134 ,  134 ′,  134 ″ (which are not necessarily equal to each other) are much greater than the lengths of the spaces  128 ,  128 ′ (which are not necessarily equal to each other). For example, preferably the lengths of said protrusion are at least twice that of said spaces, and, more preferably three times or more. 
       FIG. 2  illustrates a filter cartridge  20  that is keyed to cooperate with the head  10  of  FIG. 1 . The central neck  29  of the filter cartridge contains the connections/seals for fluid communication between the cartridge and the head. Radially spaced from the neck  29  is shoulder  32 . On shoulder  32  are two sets  33  of key protrusions  34 , generally diametrically opposed to match the locations of the two sets of lock recesses in the filter head. Each set of key protrusions includes the same number, size, and arrangement of key protrusions  34  as the filter head has lock recesses, so that the “key” of the filter cartridge fits into the “lock” of the filter head, in effect. The preferred key protrusions curve on the radius of the shoulder of the cartridge and have a curved outer surface from top to bottom. To match the recesses, each set of protrusions in the embodiment of  FIG. 2  include three “end-to-end” protrusions, sized large, medium, and small, in sizes generally equal to the recesses in  FIG. 1 . 
     In use, when the filter cartridge  20  is inserted into the head  10 , the key protrusions  34  must be matched up with the lock recesses  24  so that the filter cartridge can be moved axially into the filter head. The protrusions  34  slide into their corresponding lock recesses  24  (which are the first portion of the recess system) and the inner rim of the head extends down over the top of the filter cartridge. Then, the filter cartridge is rotated on its axis relative to the head to lock the cartridge into the head. This is made possible by the second portion of the recess system of the filter head, the radial lock portion  40 , which extends continuously above the ridges  26  for preferably, but not necessarily, a distance equal to or slightly greater than the total length of one set of protrusions. When the cartridge is inserted and rotated, the protrusions  34  slide circumferentially into the radial lock portion  40  of the recess system until being fully rotationally engaged (rotationally limited by the stop at the end of the lock portion) and are “locked” above the ridges  26  by virtue that they cannot be pulled axially downward past the ridges  26 . When the filter cartridge is fully inserted and locked into the head, as shown in  FIGS. 5 and 6 , one may see the protrusions  34  through the apertures  42  in the filter head wall. To remove the filter cartridge, the cartridge is rotated on its axis in the opposite direction to move the protrusions  34  from above the ridges  26  to again align with lock recesses  24 , so that the protrusions may slide axially down and out of the head through the recesses. Frictional means or biasing means, or other locking means, may be used to bias the filter cartridge from sliding in reverse out of the head until the user purposely removes the filter cartridge. 
     With the invented key system for filter cartridge and head, it is economical and convenient to mold sets of cartridges and heads with matching key system structure, and to mold many different sets with different key system structure. For example, for one application, a key system structure may include four lock recesses and four key protrusions in each of two sets on the cartridge and on the head, and the recesses and protrusions may be, for example, two short alternating with two long. For another application, a key system structure may include three recesses and three protrusions, all of which are long. Cartridges with the three-recess and protrusion key system would not fit into heads with the four-recess and protrusion key system, so there would be no chance of mixing up the cartridges. 
     Keyed Fluid Connector ( FIGS. 12-36 ): 
     An alternative embodiment of the invented keyed system provides the key system structure on surfaces of the filter cartridge and the holder that work to provide a fluid connection/seal in addition to physical connection.  FIGS. 12-22  illustrate one such tubular connector embodiment, comprising a bracket  210  that is a fluid-conducting holder for holding and sealing to a filter cartridge  211 . The bracket  210  and cartridge  211  include tabs and slots on the tubular connectors that create a physical connection and fluid communication between the bracket and cartridge. 
     In  FIG. 12  is shown the bracket  210  that serves several functions: mounting means for securing the bracket to a wall of other surface, fluid receiving means, inlet tube for conveying liquid to the filter connected to it (not shown in  FIGS. 12-19 , but shown separately in  FIGS. 20-22 ); outlet tube for conveying liquid from the filter; and fluid dispensing means for sending the filtered/treated liquid downstream to another filter, process, storage, or use. Specifically, plate  212  may be attached to a wall or other surface for supporting several brackets in various flow configurations. Inlet  214  and outlet  216  are at opposite ends of a conduit device  218 , and may be used so that inlet  214  receives fluid from an upstream pipe or other conduit and that outlet  216  delivers filtered fluid (that has exited the filter cartridge) to its downstream destination. The conduit device  218  directs flow into the inlet tube  220  so that the fluid may flow into the filter cartridge, and then receives flow from the cartridge into the outlet tube  222  so that it may flow out through outlet  216 . Male tubes  220  and  222  have “standouts” or tabs  225 , 225 ′ on their outer cylindrical surfaces. 
     As best seen in  FIGS. 18 and 19 , tube  220  and tube  222  have tabs  225 ,  225 ′ protruding about 30 degrees offset from each other (tab  225  of tube  220  out to the left in  FIG. 19  and tab  225 ′ of tube  222  down about 30 degrees from the tab  225  of tube  220 ). The cooperating filter cartridge  228  shown schematically in  FIG. 20  has female inlet and outlet tubes  230  and  232  (which may also be called an inlet port and outlet port), and one may notice that tubes  230  and  232  have matched or “mating” internal slots  227 ,  227 ′ to receive the tabs  225 ,  225 ′. Alternatively, of course, filter cartridges might be made with male tubes and tabs and cooperating holders may be made with female tubes and slots, in keeping with the idea that the key protrusions may be placed on either the filter or the holder, and the lock recess may therefore be placed on the other item. 
     One may see that, by varying the radial location of the tabs and slots, one could arrive at many “keys” and “locks” for the cartridge-holder sets. For example a holder could have an inlet tube with a tab at 60 degrees from a reference point and the outlet tube could have a tab at 120 degrees relative to that reference point, as long as the proper cartridge for that holder is made with the same offset and the same absolute location of slots.  FIGS. 12-20  illustrate only one of the many possible combinations of possible tab radial locations, which are extremely numerous because the radial location of each of the tubes may be varied in each set, and may be varied independently.  FIGS. 21 and 22  illustrate two of the many other possible key system structures. For example, in the top end of elongated filter cartridge  228 ′ of  FIG. 21 , the female inlet tube (port)  230 ′ is keyed at about 110 degrees, and the female outlet tube (port)  232 ′ is keyed at about 290 degrees. In the top end of elongated filter cartridge  228 ″ of  FIG. 22 , the inlet tube  230 ″ is keyed at about 195 degrees and the outlet tube  232 ″ is keyed at about 170 degrees. 
     The bracket  10  in  FIGS. 12-19  typically is installed in a process with the plate  212  vertically attached to a vertical wall. Thus, tubes  220  and  222  extend out horizontally, and the filter cartridge is pushed onto the tubes  220 ,  222  so that the tubes  220  and  222  support and connect with the filter cartridge. Associated with the tubes  220 ,  222 ,  230 ,  232  are o-rings or other sealing structure to provide liquid-tight communication between the bracket and the cartridge. Although it is not shown, one may see from  FIGS. 12-19  that liquid-tight seals are made between piping or other conduit and the inlet  214  and outlet  216 . Additionally, a fastening device may be added to further secure the cartridge in sealed relationship with the tubes  220 ,  222 . 
     As explained earlier, key protrusions may be placed on either the filter or the holder, and the lock recess may therefore be placed on the other item. Thus, the male and female tubes may be generally interchangeable on the bracket/holder and filter. For example, a male tube(s)  302 ,  304  with key tab(s)  306 ,  308 , such as shown in  FIG. 23 , may be provided on a filter  310  rather than on a bracket, and a female tube  312 ,  314  with slot(s)  316 ,  318 , such as shown in  FIG. 24 , may be provided on a bracket/holder  320 . Another example is shown in  FIGS. 25-27 , wherein female tubes  330 ,  332  with slots  334 ,  336  on a bracket/holder  338  cooperate with male tubes  340 ,  342  with tabs  344 ,  346  on a filter  350 . 
       FIGS. 29-34  illustrate examples of other key systems wherein only one of the tubular connectors is keyed. Specifically, filter  360  includes one female tube  362  having slot  364 , while female tube  366  has no slot. Male tube  370  has tab  372 , while male tube  374  has no tab. Similarly, male tube  380  has no tab, but male tube  382  has tab  384 , and female tube  390  has no slot, but female tube  392  has slot  394 .  FIGS. 33 and 34  illustrate an example of multiple slots  396 ,  397  and tabs  398 ,  399  being provided on one tubular connector (combination of  401  and  401 ′), while no key system is provided on the other tubular connector (combination of  402  and  402 ′). 
     One may note that many filter embodiments having a keyed tubular connector are not rotated on the filter axis after insertion into a cooperating holder/bracket, and need not be rotated in order to remain securely sealed to the holder/bracket. For example, once the keyed filter is inserted into/onto the holder/bracket, a pivotal lid, strap, retainer, or other fastening device may be added to further secure the cartridge to the holder/bracket, for example, by encircling a part of the top end of the filter. See, for example,  FIG. 28 , which illustrates a fastening device  405  that pivots around/onto the top end of the filter to help retain the tubular connectors in a securely sealed position. Thus, such a filter is usually not “twisted,” “screwed,” or otherwise rotated it on its axis in order to secure it into its holder, and, thus, the key and lock (such as a tab and slot) of such a filter slide together to mate but typically do not slide past each other, as they do not need to “clear” each other to allow rotation of the filter relative to the holder. This is especially the case when a filter and holder/bracket features two adjacent tubular connectors, wherein the female or male tubes acting as inlet and outlet ports on the filter are not both (and perhaps neither) located on the longitudinal axis of the filter. Such a filter will slide onto/into its holder, mating with the tubular connector tubes (male or female) of the holder/bracket, and will not be able to rotate relative to the holder/bracket because the filter is fixed to the holder/bracket at two places that are adjacent but not coaxial with each other. Therefore, the preferred keyed tubular connector system is one in which the key(s) and lock(s) of the female and male tubes of the tubular connector(s) are mated and in contact during installation of the filter into/onto the holder and continue to be mated and in contact during use of the filter, as opposed to sliding past each other so that the filter may be rotated relative to the holder. 
     Universal Key and Adaptor System 
     Preferably, the invented system also includes an optional universal key feature that may be supplied to the client/customer, wherein a single “universal cartridge” is made that may be used on a plurality of differently-keyed filter holders. The “universal” cartridge may be, for example, a cleaning cartridge, a sanitization cartridge, a media regeneration cartridge, a special treatment cartridge, or a testing cartridge, wherein it is more convenient and economical for the user to have a universal cartridge fitting all of the user&#39;s or manufacture&#39;s variously-keyed holders. This may be, for example, because the user wants to use a single universal cartridge for cleaning of all his various filtration or treatment processes and does not want to invest in differently-keyed cleaning cartridges for each differently-keyed holder. Also, this way, a manufacturer that supplies different customers with large volumes of differently-keyed holders and cartridges (for their main filtration and treatment process) may supply all the customers with the same universal-key cartridge for special or infrequent processes such as cleaning or media regeneration. This allows the manufacturer to maintain profitability even on the small volumes of cleaning or other infrequent-use cartridges that are required, by saving the expense of manufacturing and monitoring proper shipment of many differently-keyed cleaning cartridges. 
     The universal cartridge includes a “lock recess” or “key protrusion” (depending on whether the system is a recess-on-cartridge or a protrusion-on-cartridge system) at every location where any of the holders involved have a corresponding recess or protrusion. For example, if a manufacturer produces holders and cartridges that are keyed with recesses and protrusions at 30 degree increments, the universal cartridge for the holders involved will have recesses or protrusions at every 30 degrees. For example, if a manufacturer produces holders and cartridges that have recesses and protrusions on fluid tubular connectors at 12 o&#39;clock and 5 o&#39;clock for one client and at 3 o&#39;clock and 11 o&#39;clock for another client, that manufacturer may produce a universal cleaning cartridge with recesses or protrusions at all of the positions of 12, 3, 5, and 11 o&#39;clock. 
     While the preferred keyed system includes keying of the holder and the filter cartridge, it may also include keying of an adaptor that is keyed to properly fit and cooperate with the keyed structure of the holder, and that has an unkeyed connected to a conventional, unkeyed filter cartridge. Thus, while figures such as  FIGS. 20-22, 28, 29, 32, 34, 35, and 36  may illustrate keyed top ends of filter/cartridges, the “top end” structure drawn in these figures could also be the structure of an adaptor, which fluidly connects to the keyed holder/bracket as shown and described, and which receives a non-keyed cartridge at its lower end, for example, inside a lower, interior concave space having fluid connections between the non-keyed cartridge and the adaptor. 
     Preferred Universal Key Option 
     For the tubular-connector-type keyed system, and for many of the various possible keyed systems for filter cartridges and filter holders, a universal key is desirable as an option for some circumstances. This universal key preferably takes the form of a filter cartridge that is adapted to fit any and all of the various differently-keyed holders that a manufacturer supplies to a single client/customer, or, alternatively, a filter cartridge that is adapted to fit any and all of the various differently-keyed holders that a manufacturer supplies to all of its clients/customers. This allows an economical answer to the issue of providing differently-keyed main process filtration or treatment cartridges to a customer or to several customers while providing a single cleaning or other infrequent-use cartridge to a customer for all the customer&#39;s special applications, or to all customers for all their special applications. In other words, while there are good reasons to provide differently-keyed cartridges to different customers or to a single customer for his various uses, it may be important to have a single cartridge that is usable in all the customers&#39; filtration/treatment systems, or at least in a plurality of differently-keyed holders. 
     A universal key system preferably comprises a filter cartridge that is adapted to fit a plurality or all of the differently-keyed holders that a manufacturer makes or that are supplied to a client/user. For example, in  FIG. 35  is shown schematically a top end  528  of (or may be formed as an adaptor for) a filter cartridge that is adapted to fit onto all three of the holders for which the three cartridges  228 .  228 ′,  228 ″ in  FIGS. 20, 21, and 22  are made. That is, the  FIG. 35  cartridge  528  has ports  530  and  532  that have multiple slots  561 ,  562 ,  563 ,  564 ,  565 ,  566  that extend radially from the center of the ports and that are positioned so that cartridge  528  will slide onto and properly liquid-seal with the three holders. This way, cartridge  528  is “universally-keyed” with a total of six slots to fit a plurality of holders, which holders each have only one slot per port. 
       FIG. 36  illustrates a universally-keyed cartridge top end (or adaptor) that is keyed to fit with any and all holders that have tabs on male tubes that are positioned straight up (at “12 o&#39;clock”) and at various positions 45 degrees from that. For example, each of the two cartridge top end female tubes has eight slots radially extending out at straight up (0 degrees), 45 degrees, 90 degrees, 135 degrees, 180 degrees, 225 degrees, 270 degrees, and 315 degrees. This way, there are many combinations of one or more tabs on each of the male tubes that may be provided to a customer or customers, and the single cartridge in  FIG. 36  will fit onto any of these 45 degrees version male holders. This way, the manufacturer may supply the same universally-keyed cleaning cartridge for many different customers that have requested differently-keyed cartridges for their main filtration/treatment processes. 
     After reading this description, one may understand that a universal key cartridge may be supplied for various keyed systems. For example, a universal key cartridge may be made for a keyed system wherein a filter cartridge shoulder that does not liquid seal to a valve head may include the appropriate universal-keying to fit into several valve heads with different key structures. Or, a tubular connector type system may include otherwise-shaped tabs and slots, for example, such as rounded bump-shaped tabs and slots. 
     Although this invention has been described above with reference to particular means, materials and embodiments, it is to be understood that the invention is not limited to these disclosed particulars, but extends instead to all equivalents within the scope of the following claims.