DESCRIPTION

BACKGROUND OF THE INVENTION

Field of the Invention. The present invention relates generally to compact liquid filters for use by individuals in regions or countries where water is not reliably potable and may contain microorganisms such as viruses, bacteria, and/or cysts. Further, the present invention may relate to filters for installation in a water or other beverage bottle, such as the common sports bottle used in outdoor recreation and sports, or such as a canteen or flask used in military, humanitarian, or emergency services, for example.

Related Art. Various filters have been designed for water or beverage bottles that are carried by individuals recreating or working in areas where potable water is not conveniently available. Such individuals are bicyclists, hikers, boaters, vacationers, campers, workers, emergency responders, or military personnel in remote areas, or even those in urban areas where water is suspected or known to be contaminated. Examples of water container filters include: Iana, et al. (U.S. Patent 5,122,272, issued June 16, 1992); Kay (U.S. Patent No. 5,417,860, issued May 23, 1995); Lonneman (U.S. Patent No. 5,545,315, issued August 13, 1996); Hughes, et al. (U.S. Patent No. 5,840,185, issued Nov. 24, 1998); Hatch, et al.(U.S. Patent No. 5,928,512, issued July 27, 1999); Smith, et al. (U.S. Patent No. 6,136,189, issued October 24, 2000); and Nohren, et al.

(U.S. Patent No. 6,165,3562, issued December 26, 2000). Important issues in the design of in-bottle filters have been filtered water flowrate; air venting; effectiveness of deactivating or removing viruses, bacteria, protozoa, and other contaminants; and filter plugging and filter life. In spite of the many previous designs, there is still a need for an in-bottle filter that is improved in some or all of these areas. The inventor believes that a need especially exists for an improved in-bottle filter that has an effective water flowrate, is comfortable to use, and deactivates, kills, or removes viruses, bacteria and cysts. SUMMARY OF THE INVENTION The present invention comprises a filter cartridge that has biocide capability, and that has a serpentine biocide zone flow path that provides an effective path length within a compact shape. The preferred filter cartridge or cartridge assembly has a biocide zone and the post-biocide zone that are closely adjacent, for example, generally concentric and generally side-by-side and/or axially overlapping, even though the two zones are in series flow. The preferred cartridges are short relative to the length of a typical hand-help bottle, and may be positioned entirely, or substantially entirely, within the cap and/or neck of the bottle. The preferred cartridges, therefore, may provide for substantially all of the water in the bottle to be filtered and drinkable, because, upon tipping of the bottle, substantially all of the water will pass through the cartridge, rather than flowing to or being held in "dead zones" from which the cartridge inlet(s) is/are not accessible to the liquid. Some embodiments of the invented serpentine biocide flow path system features at least a portion of the biocide zone protruding into at least a portion of the post-biocide zone. Some embodiments feature at least a portion of the post-biocide media zone being positioned coaxially around at least a portion of the biocide zone. Some embodiments feature at least a portion of post-biocide media zone being positioned coaxially inside the biocide zone. An object of some embodiments of the invented filter cartridge is to provide a compact, easy- and comfortable-to-use water or beverage bottle filter. An object of some embodiments is to provide a compact filter for other applications, such as a water faucet or tap. An object of the preferred cartridges is to deactivate or kill bacteria, viruses, and/or cysts that may be in the liquid, and to provide potable water even in remote or underdeveloped areas. Another object of the preferred cartridges is to filter out iodine, chlorine, or other impurities, in order to improve the taste of the water. Another object of the preferred cartridges is to maximize the amount of liquid in a portable water bottle that is drinkable due to the filter not extending deep into the bottle or otherwise creating large dead spaces. Another object of the preferred cartridges is to provide an easily- vented bottle, and a filter cartridge that stays mostly liquid-full, when the user pauses from drinking. These and other objectives of various embodiments of the invention will be apparent from the following description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Figure l is a schematic flow chart of some, but not the only, filtration or treatment processes of some embodiments of the preferred filter cartridges. Figure 2 A is a cross-sectional side view of a first in-bottle embodiment of the invented filter cartridge installed in a cap and bottle combination, wherein the one embodiment of a post-biocide media zone is positioned generally coaxially around one embodiment of a biocide zone, and wherein a combined biocide and dwell module or portion provide a serpentine flow path. Figure 2B is a cross-sectional view of the embodiment of Figure 2 A, with the dwell chamber filled with biocide. Figure 3 A is a cross-sectional view of the embodiment of Figure 2B, with flow lines shown during drinking. Figure 3B is a cross-sectional view of the embodiment of Figure 2B and 3 A, shown when compression on the bottle is released and water has drained from some of the filter cartridge, wherein water remaining in the filter cartridge is shown in horizontal dash-dot- dash lines. Figure 4 is an exploded view of one of many possible manufactures of the embodiment of Figures 2 and 3. Figure 5 is a cross-sectional view of another in-bottle embodiment of the filter cartridge installed in a cap and bottle combination, with flow lines shown during drinking, wherein another embodiment of a post-biocide media zone is positioned generally coaxially inside another embodiment of a biocide zone, and wherein the biocide zone is a generally cup-shaped cartridge module or portion that provides a serpentine flow path. Figure 6 is a cross-sectional bottom view of one embodiment of the cup of Figure 5, wherein the bottom of the cup, and portions of media, have been cut away, to better view the preferred internal chambers. Figure 7 is a cross-sectional bottom perspective view of the cup of Figures 5 and 6, wherein the top and bottom wall, and portions of media near said walls, have been cut away to better view the preferred internal chambers and flow lines there-through. Figure 8 A is a detail view of one embodiment of a vent for bottles of the invention, wherein the vent is closed. Figure 8B is a view of the vent of Figure 8 A, wherein the vent is opened to allow air to enter the bottle. Figure 9 A is a cross-sectional view of another in-bottle embodiment of the filter cartridge installed in a cap and bottle combination, wherein another embodiment of a post- biocide media zone is positioned generally coaxially inside another embodiment of a generally cup-shaped biocide cartridge module or portion. Figure 9B is a cross-sectional view of the embodiment in Figure 9 A, with flow lines shown during drinking. Figure 10 is a cross-sectional view of an alternative embodiment of the cartridge, featuring the biocide cartridge module or portion of Figures 9A and B, with a simplified radial flow exit media zone. Figure 11 is a proximal end view of the cup-shaped biocide media module or portion of Figures 9A, 9B, and 10, with dashed circles indicating inlets into a first passage, and arrows indicting outlets from last passage, of a serpentine flow path. Figure 12 is a side view of the cup-shaped biocide media module or portion of Figures 9A, 9B, 10, and 11. Figure 13 is an end view of one embodiment of a sediment filter, illustrating one embodiment of a housing for said sediment filter.

DETAILED DESCRIPTION OF THE INVENTION Referring to the Figures, there are shown several, but not the only, embodiments of the invented filter cartridge, which preferred embodiments feature nearly total availability of the liquid to the filter, good flowrates, and comfortable handling, for convenient drinking from a hand-held bottle in a tip-back manner. Figure 1 illustrates some of the many possible arrangements for filtration/treatment that may be incorporated into cartridges according to the invention. Figure 1 notes that several of the zones and steps are "optional," but this is not to indicate that all the steps not marked as optional are required or that additional steps/zones may not be added. One of skill in the art, after reviewing this disclosure, will be able to design cartridges according to the invention to meet many different needs and uses. The preferred filter cartridge is installed as an in-bottle filter cartridge that may be used by tipping or tilting the bottle upwards to the mouth and/or by squeezing the bottle, as with a typical hand-held "sports" or "bottled water" bottle. Alternative uses for the invented filter cartridges may be found, for example, installation on a faucet or other water tap. The preferred filter cartridge is preferably installed inside a cap or extended neck of a water or other beverage bottle. The filter cartridge preferably does not extend any significant distance into the interior volume of the bottle, but rather is entirely, or substantially entirely, inside a neck or cap of generally the same diameter as the cartridge. In other words, the preferred filter cartridges do not extend very far into the main volume of the bottle, and especially do not extend to the bottom of the bottle. This way, upon comfortable and "normal" tipping of the bottle upwards for drinking, nearly all the water contained therein may be filtered and drunk. There are few "dead" spaces for water to reside in the bottle, that is, spaces from which water will not flow into the filter or out the bottle nozzle or other drinking opening.. In many embodiments, very small space(s) exist between the preferred filter cartridge and at least a portion of the bottle neck, for example, a small, generally annular space between the internal surface of the neck and the external surface of the cartridge. In embodiments wherein the liquid inlet to the cartridge is at or near the bottom end of the cartridge, these space(s) between the cartridge and the neck may be dead spaces from which the liquid does not enter the cartridge, but, they are so small that they hold an insignificant amount of liquid compared to the volume of the bottle. These spaces may also form an air channel between an air vent in the bottle cap and the interior volume of the bottle, as described later in this Description. Alternatively, for embodiments wherein the liquid inlet to the cartridge is not at or near the bottom end of the cartridge, these space(s) may be adapted to form one or more paths along the side of the cartridge to the liquid inlet(s). Each of the preferred embodiments of the invented filter cartridge are adapted so that the liquid flowing through the cartridge "reverses" direction at least at two locations in its path through the cartridge. The terms "reverse" and "reversal" mean that the flow of liquid turns a corner or curve in the filtration path of greater than 90 degrees, and more preferably between 135 to 180 degrees, during the normal course of filtration - not that flow through a given zone or compartment proceeds first in one direction and then, later, through that same zone/compartment in the opposite direction. Preferably, at least one, and more preferably at least two, of the direction reversals occurs in the biocide zone, and, in this way, a long passage of biocide is provided within a short overall cartridge length. In some embodiments, this reversing of direction in the biocide zone may be combined with placement of the inlet and outlet of the biocide zone at one end of the zone, and this arrangement may be beneficial in designing a biocide zone and post-biocide zone that are generally side-by-side and/or at least partially "one inside the other." This is because it may be convenient to design a cartridge that has liquid leaving the biocide at or near the distal end of the cartridge, and then flowing into post-biocide media that is also near that end of the cartridge. The first embodiment of an in-bottle filter cartridge preferably comprises a pre-filter, a biocide zone, an extended biocide or dwell zone, and a post-biocide or "exit media" zone that may be adapted to remove biocide, other chemicals, metals, and/or cysts, for example. Upon entering the biocide zone, liquid flows proximally through a first axial biocide passage and then turns to flow distally through a second axial biocide passage. The second axial biocide passage is preferably adjacent to, and preferably, annularly surrounding the first axial biocide passage, so that said first passage may be considered to be inside the second axial passage. The first passage and second passage are separated along most of their lengths, by an axial cylindrical wall, but are in fluid communication at their proximal ends, so that liquid turns generally 180 degrees when flowing from the first to the second passage. The extended biocide/dwell zone preferably is an annular space surrounding and in fluid communication with at least a portion of the outer annular portion of the biocide bed, wherein liquid turns generally 90 degrees from the second passage to enter the extended biocide/dwell zone. In the extended biocide/dwell zone, liquid turns generally another 90 degrees to flow to the exit media zone, which at one end is in axial fluid communication with the extended biocide/dwell zone and at the other end is in axial fluid communication with the bottle cap nozzle. In order to limit the axial length required for the first embodiment of filter cartridge and the cap or bottle neck, the preferred exit media zone has an annular portion that extends around the outside of the biocide zone. In this way, the biocide zone may be said to be inserted or extending into a central space inside the exit media zone. While the flow through the exit media zone is substantially axial, it also has a radial component, due to the exit zone's inlet being spaced radially from the exit zone's outlet near the bottle nozzle. In the first embodiment, the water or other beverage enters the preferred biocide zone axially up through the center of the biocide bed, and then reverses by changing direction to flow axially the opposite direction through the outer annular portion of the biocide bed. The water then reverses again by flowing radially outward to the extended biocide/dwell zone and then generally axially into and through the exit media zone and to the nozzle. In a second embodiment, the liquid reverses direction several times while it flows around an annular ring having various side-by-side axially-provided compartments. The second embodiment may be an in-bottle filter cartridge also comprising a pre-filter, a biocide zone, an optional dwell zone, and an exit media zone that may be adapted to remove biocide, other chemicals, metals, and/or cysts, for example. The biocide zone and optional dwell zone are preferably located in a cup structure formed by a double-walled annular ring structure with a plurality of axial divider walls all around the ring structure. The liquid may flow axially into the annular ring structure preferably at one inlet region in the ring, and then, due to the fluid communication between the plurality of axial compartments created by the divider walls, the liquid will flow "up and down" through the various compartments around the ring structure in multiple flow-reversals. The ring structure preferably will have one radial outlet region at the bottom of the ring into the interior bottom of the cup, from where the liquid flows into the exit media zone, which is preferably an axial flow bed inside the annular ring structure. Alternatively, in third and fourth embodiments, the exit media zone may be a radial flow bed with optional media contained within an axial flow space at the outlet of the radial flow bed. Alternatively, inlet(s) and outlet(s) into and out of the cup structure may be in other than bottom regions of the cup structure. For example, there may be inlet(s) higher up or spaced along the outer sidewall of the cup structure, for example, fed by liquid flowing into the space between the cartridge and the bottle neck wall. Also, for example, there may be outlet(s) higher up or spaced along the inner sidewall of the cup structure, wherein liquid from such outlet(s) would be well-located for entering a radial flow exit media zone, for example. The preferred flow-reversals in the biocide zone increase the overall length of the biocide flow path in an axially-short, compact zone, followed by effective biocide removal and/or other post-treatment, still within a compact cartridge. The flow-reversals typically are created by baffles (that is, a plate, wall, screen, or other device to deflect, check or regulate flow) that creates a serpentine flow path in a zone that longer than the overall length of that zone module or housing.

Referring specifically to the Figures: While four embodiments are described below in detail, these embodiments are not to be construed as the only embodiments of the invention. While particular structures, means, and materials are used to illustrate preferred features of these four embodiments, it is to be understood that the invention is not limited to these disclosed particulars. In this description, the terms "proximal" and "distal" refer to the directions toward, and away from, the user's mouth when drinking from the nozzle of the bottle. In this description and the claims, the term "cartridge" is used, which may include an integrally formed housing with multiple filtration/treatment zones contained there, that is typically not taken apart after manufacture. Also, the term "cartridge" may also include a cartridge assembly that has multiple but separable filtration/treatment zones, such as filter bed modules, typically contained within separate but cooperating housings that screw, snap, slide, or hook together, or otherwise connect prior to use. Thus, the zones may be housed in a single housing with baffles such as partition walls, or in multiple housings that cooperate, connect, and seal to create an effective filtration unit with fluid communication between the multiple zones. Accordingly, the term "housing" may include a single housing or multiple housings, walls, baffles, etc., as needed to house and contain the media and fluid flow. When a housing is a "single housing," the various walls and other portions of the single housing may be integrally molded or otherwise formed as a single unit, or may be separately formed and connected by sonic welding or adhesive, for example. The term "zone" is a broad term that may include any of various filtration or treatment regions for effecting desired operations, including, but not limited to, beds, blocks, woven assemblies, layered or stacked assemblies, impregnated or coated support structures, or other filtration or treatment media with or without baffles and media containment structure, and/or also empty regions or regions that effect physical operations such as mixing or flow control. Referring to Figures 2-9B, filter systems 1, 2, 3 include filter cartridge embodiments 10, 100, 300 that are illustrated as removably inserted into an elongated neck 12, which extends from the main body of bottle 14. Referring to Figures 10 - 12, there is shown another cartridge embodiment 300', similar to that in Figures 5-9B, that is not illustrated as contained within a bottle. The four embodiments illustrated herein include an attachment mechanism for securing it to a bottle or other structure, but these and many others according to the invention, may be adapted for connection to other structure and/or for uses other than a hand-held bottle, without extending beyond the scope of the invention. Referring again to cartridges 10, 100, 300, these embodiments are illustrated inside a bottle 14 having a neck 12 and a connected cap 16 and nozzle 18 at the proximal end of the neck 12. The neck 12 may be integrally or non-detachably connected to the main body of bottle 14, and access to the filter cartridge may be gained by means of a threaded or other detachable connection 22 between the cap 16 and the neck 12. Preferably, when cap 16 is removed from the neck 12, the filter cartridge 10, 100, 300 stays with the cap 16, due to a friction fit or other connection between the cartridge 10, 100, 300 and the inside surface(s) of the cap 16. This, way, one may remove the cap 16 and easily access and replace the cartridge 10, 100, 300. While a conventional pull-to-open and push-to-close nozzle 18 on the cap, other drinking ports may be used, such as a flip-open-lid-style port, flip-open-straw- style port, or twist-open port, as are known in convenience and sports bottles. Various connection and sealing systems may be used to connect the filter cartridge to the cap, bottle, neck, or other structure with which the filter cartridges are being used, and to connect the preferred modular zones of the cartridge to each other. It should be understood that alternative connections and seals, or combinations of connections and seals, may be used, including but not limited to, friction-fit, threaded connections, snap-together connections, or bayonet connections, with o-ring(s) and/or gasket(s) or other sealing surfaces. The housing of the filter cartridge is preferably made of polypropylene or other polymers and plastics, while other materials may also be used. The cartridge may be separate but connectable to a cap, bottle, or other cooperating structure, or may be integral with said cap, bottle, or cooperating structure. In cartridge embodiments that are temporarily and removably installed in a bottle, the preferred filter cartridge is easily removable from the neck 12 and the nozzle cap 16, and so may be disposed of without significant disposal problems and without significant waste of plastic. Alternatively, the outer housing of the filter cartridge may be an extension of the cap that threads or otherwise connects to the main body of the bottle, so that the cap and filter cartridge are a single unit that connects and seals to the neck of a bottle, in which case removing and discarding the cartridge serves to remove and discard the cap, nozzle and the filter cartridge together. Also, alternatively, the filter cartridge, cap, and neck may be a single unit, that connects and seals to a bottle, in which case the cap plus neck is really an elongated cap for the bottle with the cartridge contained therein. In such a system, removing and discarding the cartridge serves to remove and discard the cartridge, cap, nozzle and neck together. Such systems may result in less access to the filter cartridge, and more waste or recycling of plastic, but may be practical in some applications.

Embodiment One Describing filter cartridge 10, shown in Figures 2 - 4, starting from its inlet end to its outlet (at or near nozzle 18), a pre-filter 30 is positioned generally in the broad inlet opening 32, with a distribution space 34 immediately proximal to the filter 30. While an axial-flow sediment filter is preferred as the pre-filter 30, the filter/media in this position may instead or additionally comprise a one micron filter for cysts or other media specially selected for other contaminants. Further, pre-filter 30 or other filter in or near the inlet opening 32 may be radial flow instead of axial flow, for example, from the outer wall of the filter cartridge to near the central inlet of the biocide media bed 40. Liquid flows through the distribution space 34 into the central portion 36 of the biocide media bed 40. At the end of this axial-flow central portion 36, the liquid turns direction to flow radially a short distance and then axially through the outer annular portion 42 of the biocide media bed 40, thus, reversing direction. In this portion 42, flow is generally in the opposite direction as in the central portion 36, that is, preferably 180 degrees from the flow in portion 36. Central portion 36 may be described as inside, coaxial to, and preferably surrounded by the outer annular portion 42. The preferred biocide media bed 40 is at least partially, and preferably entirely, loaded with biocide, such as I3 or I5 iodine resin. During contact with this iodine resin or other biocide media, the liquid picks up iodine or other biocide, and carries it downstream. At or near the distal end of the annular portion 42, liquid turns about 90 degrees to flow through apertures 44 in wall 46 into a chamber 48 circumferentially extending around the distal end of the annular portion 42. This chamber 48 is preferably also full of biocide (system 1', cartridge 10', Figure 2B). Optionally, chamber 48 may be an empty (except for the water) space that is used for extended dwell time for the liquid, to increase contact time with the biocide in the liquid (Figure 2A). This way, after passing through the biocide bed 40, the liquid experiences additional residence time in contact with the biocide resin (Figure 2B) or in contact with biocide contained in the water (Figure 2A), before the biocide is removed by downstream media. The biocide therefore has more time to deactivate or kill bacteria, viruses, and/or cysts. A preferred contact time for bacteria and viruses is 1-3 seconds, and preferred contact time for cysts is 5-10 minutes. Alternatively, chamber 48 may be filled with other media., baffles, screens, or other materials. The liquid flows axially through the chamber 48 and passes to the exit media zone 50 via apertures 52. Exit media zone 50 may be loaded with granular activated carbon (GAC), silver-impregnated granular activated carbon (SGAC), or other media or mixtures or layers of media. Preferably, the media in exit media zone 50 removes the biocide, and may also remove cysts, metals or other contaminants. Exit media zone 50 at its proximal portion 53 preferably extends substantially all the way across the diameter of the filter cartridge 10. The exit media zone 50 extends distally from portion 53 to an annular portion 54 that extends circumferentially around the proximal end of the biocide media zone 40, and, more specifically, around the proximal end of the outer annular portion 42. One may see, therefore, that the biocide media bed 40 is "inserted" part way into the center of the exit media zone 50, so that the biocide zone and post-biocide/exit zone are generally coaxial and axially overlapping for at least a part of their axial lengths, and preferably so that the exit module overlaps about 1A - 3/4 of the length of the biocide module. As will be understood after viewing the drawings and reading the Description, appropriate housings or housing portions, screens and/or pre- and post-filters will be installed to properly retain the preferred media in their respective zones and/or to provide further filtration. For example, such screens/filters may be positioned at the inlet of the biocide media (33), at the outlet of the biocide media (44), at the inlet of the exit media (52), and at the outlet (49) of the exit media zone 50. The filter cartridge 10 is adapted for axial flow through inner and outer portions of a biocide media (in opposite directions), radial flow into a dwell zone and axial flow out of the dwell zone to a substantially, but not entirely, axial exit media zone. The liquid flow, therefore, turns about a 180 degree corner, followed by first and second 90 degree corners that combined may be considered another 180 degree turn, followed by flow with both an axial and radial component toward the nozzle. A "180 turn" may therefore comprise one tight 180 degree turn, or multiple sequential turns within a short distance that add to 180 degrees. This "serpentine" ("winding or turning one way and then another", Webster's Third New International Dictionary, 2002) flow pattern preferably comprises two 180 degrees turns before the liquid enters the post-biocide zone. In the embodiment shown in Figures 2- 8, bothl80 degrees turns are inside the biocide module or portion which includes biocide media and optional dwell space . By the time the liquid enters the post-biocide zone, it is flowing through an annular zone (annular portion 54) preferably coaxial with and axially overlapping with the biocide zone; only near the end of the flow path through the cartridge, near the nozzle, does the liquid leave the region (portion 54) where the post-biocide media is axially overlapping the biocide media and enter the region (proximal portion 53) which is not axially overlapping with the biocide media. In use, the person desiring to drink from the bottle 14 typically tips the bottle's end upward and squeezes the bottle to force liquid out of the nozzle. The water inside the bottle follows the path described above to the user's mouth. The filter cartridge preferably takes up nearly all the space inside the bottle neck and does not extend any significant distance into the main body of the bottle. This way, there is very little distance and very little "dead space" between the bottle neck wall and the outer wall of the filter, so there is very little water that flows between the bottle neck wall and the outer wall of the filter. Therefore, the user can drain the bottle substantially dry and will not experience the frustration, which is typical of many prior art designs, of being able to drink only a relatively small portion of the liquid, or of having to keep the bottle vertical to "sip" through a filter straw extending to the bottom of the bottle. When the user stops or pauses from drinking and releases the compressive force on the bottle, the bottle will take in air through vent 60 or other vent(s) into the bottle. The air may travel along the outside of the filter cartridge, preferably through one or more small gaps 62 between the outer wall ring/shirt 64 of the cartridge and the interior surface of the neck 12. The gaps 62 may be one of more very small channels between the ring/shirt 64 and the neck 12 or a small annular space substantially around the entire outer surface of the cartridge. Due to the preferred friction fit or other connection of the cartridge inside the nozzle cap 16, the cartridge does not tend to "wobble" inside the neck, in spite of the space between the cartridge and the neck that allows air to pass around/along the cartridge to reach the interior volume 70 of the bottle. When the bottle vents and the bottle is orientated generally vertically, water from the distribution space 34 and the central portion 36 will tend to drain down into the bottle interior volume. The other spaces, including the outer annular portion 42, dwell chamber 48 and at least the exit zone distal portion 54 will tend to stay at least partially liquid full, shown as the dash-and-dot-line regions "W" in Figure 3B, at least in part because of the 180 degree turn inside the biocide media bed between portion 36 and portion 42. This way, when the user resumes drinking, the filter cartridge 10 is already partially full and the bottle does not have to refill the entire filter cartridge 10 with liquid before the liquid reaches the nozzle. Within a brief amount of time spent compressing the bottle, that "lost portion" of liquid has been replaced in the filter cartridge, and water is again reaching the nozzle for drinking. One example of manufacture of some embodiments of the in-bottle filter cartridge 10 is shown in Figure 4, but many other wall structures may be used as will be understood by one according to one of skill in this field. From right to left, Figure 4 illustrates the bottle 14 with neck 12, a pre-filter module 30 that may be a sediment filter, a biocide module 40 having within it extra space between flange walls 65 and 67 for additional biocide media or for dwell space, post-biocide or "exit" module 50, and cap 16. Pre-filter module 30 may slide or otherwise enter into, and seal with, the distal end of module 40. The generally cylindrical main body 66 or "bullet" portion of module may slide or otherwise enter into, and seal with, exit module 50. The generally cylindrical neck of exit module 50 may slide or otherwise enter into, and seal with, the cap 16. One may see in Figure 4, that the biocide module 40 comprises a ring or skirt 64 that extends both proximally (64') and distally (64") from the "flange" portion of the biocide module 40, wherein the flange portion extends radially from main body 66 of the biocide module 40 and the flange, and chamber 48 contained within, are defined and surrounded by flange walls 65 and 67 (on proximal and distal ends, respectively), and by the main body 66 wall and a portion of the cylindrical skirt 64. The skirt 64 may extend around and seal with o-rings 01, 02 on both the pre-filter 30 and the exit media module 50, to connect the biocide module 40 and the exit media module 50. One may also see that o-rings 03 on the exit media module 50 may seal inside the cap 16. Skirt 64, walls 65, 67, and the main body 66 wall may be integrally molded or otherwise formed as a single unit, or may be separately formed and connected by sonic welding or adhesive, for example. As discussed above, the filtration systems shown in Figures 2A and 2B differ in that media has been added to chamber 48 in Figure 2B, wherein, in the preferred modular assembly of Figure 4, the chamber is an internal volume of the flange portion described above. As discussed above, the media is preferably biocide media for extending liquid contact with biocide, but this media could be other types and materials. In the detail views of Figures 8A and 8B, one may see an example of a one-way vent/relief valve that may be used in the embodiment of Figures 2-4, in the cap and/or in other locations on the bottle, to allow air to flow back into the bottle upon release of compression. Valve 60 may be inserted into a hole in the cap. Valve 60 may have flexible flap 61 that seals against the inside surface of the cap, for example, when the bottle is being compressed. When the compression on the bottle is released, the flap 61 is pulled inward, allowing air to flow through the hole(s) 63 around the one-way valve 60, past the cartridge 10, and into the interior volume 70. There may also be an optional flow control valve (not shown) positioned at the outlet nozzle or at the biocide zone inlet, for example. Filter cartridge 10 is substantially or preferably entirely symmetrical around its central axis, and the water inlet and outlet are also symmetrical and continuous around the axis. Therefore, the bottle need not be oriented in a particular way for drinking and/or for venting the bottle. While Figures 2-4 show friction fits with o-ring seals between the cartridge and the cap 16, and between the various modules of the cartridge, it should be understood that alternative connections and seals may be used, for example, threaded connections, snap- together connections, or bayonet connections, with o-ring(s) and/or gasket(s).

Embodiment Two. Having Ring/Cup Structure As shown in Figures 5 - 7, the internals of filter cartridge 100 are different from the first embodiment, but they still achieve effective performance in a minimum of overall cartridge length. In this embodiment, the biocide media passages 140, and preferably the dwell passages 148, are positioned around the exit media zone 150. The biocide media passages 140 and dwell passages 148 are preferably adjacent, axial, series-flow passages inside ring 155, wherein the ring 155 is the generally cylindrical double-wall portion of cup module 170. Describing the filter cartridge 100 from its inlet to its outlet near the nozzle, the filter cartridge 100 features an inlet pre-filter 130, which may be a sediment filter, a one-micron cyst filter, or other pre- filter as desired, preferably friction fit and o-ring sealed into a skirt 164 extending distally from cup module 170. From filter 130, the liquid flows into a distribution space 134, from which the liquid enters one of the axial biocide passages 140 in the outer annular ring 155 of the preferred cup module 170. The liquid flows axially through passage 140, and then turns 180 degrees at the end of the passage, and flows in reverse through the adjacent passage 140'. From the passage 140', the liquid reverses again 180 degrees to the adjacent axial passage 140", and so forth. Thus, the liquid "zig-zags" "up and down" (proximally and distally) through the passages around the ring 155, flowing in a serpentine path around the ring 155. At the end of the desired number of biocide passages, as determined by the desired volume of, and contact time with, biocide, additional axial passages' in the ring are preferably left empty as dwell chambers, also in series flow. In this example of twelve passages in Figure 6, six are shown full of biocide (including 140, 140', 140") and six are shown as empty dwell passage (including 148, 148', 148). After the liquid has flowed through preferably all of the ring, the liquid exits radially from outlet 156 into a radial space 157 at the bottom inside of the cup, which space 157 may also be a dwell chamber or may contain a media. One may see that the preferred embodiment of this biocide module may be called a "cup" because of its bottom wall 158 (above which is radial bottom space 157) and its concentric upending ring walls 165, 167 forming passages (140, 148, etc.). The inlet to and outlet from the passages 140, 148 are preferably at or near the bottom of the cup, but, as discussed earlier in this Description, alternative embodiments may feature inlet and/or outlet at different positions on or in the cup. The cup module 170 having ring 155, therefore, may be said to feature multiple beds of media, preferably biocide media, separated by baffles or other walls to form a serpentine flow path having a plurality of flow reversals. The preferred cup module 170 features reversals that are sharp 180 degree turns, wherein the flow reverses due to single walls separating closely adjacent passages, but, alternative embodiments may have other flow passages and patterns. As discussed earlier in this Description, a "180 degree turn" may be made up of two 90 degree turns, for example, and therefore need not be a sharp, immediate turn. Preferably, there are three or more reversals, and most preferably three or more 180 degree turns, in the cup module, resulting in a long, winding path for enhanced biocide contact and mixing with the liquid. From radial space 157, the liquid flows axially (proximally) into the "central media bed" (exit media zone 150), which is preferably full of granular activated carbon (GAC) or silver-impregnated granular activated carbon (SGAC) or other media that can remove the I3 or I5 or other biocide, cysts, and/or other target contaminants. Figure 5 illustrates that exit media zone 150 is inserted into the central space of the cup module 170 and therefore axially overlaps the ring 155. For example, the exit media zone 150 may extend almost fully into the cup 170, so that the biocide zone and post-biocide/biocide-removal zone are generally coaxial and axially overlapping for at least a part of their axial lengths, preferably so that the exit module overlaps greater than 1/2, and more preferably about 5/8 - 7/8, of the length of the biocide module. Figures 6 and 7 schematically illustrate the various passages of the cup 155. Note that, in Figures 6 and 7, the bottom wall 158 and the top wall 159 are not shown, as the cross-section of Figures 6 and 7 are taken generally at the locations shown in Figure 5 and labeled as "Figure 6, 7." It may be noted that Figure 5 illustrates ring 155 as having non- media filled regions near bottom wall 158 and top wall 159, but, alternatively, these regions may be full of media. When the user of this embodiment pauses from drinking and releases pressure on the bottle, air is vented into the bottle via a vent/one-way- valve 60, as discussed above for Embodiment One and as shown in Figures 8 A and B. When the user is no longer drinking, the user will typically lower the bottle from the tipped-up position and release compression of the bottle. A limited amount of water will fall down out of the filter cartridge. In a similar manner to the first embodiment, the 180 degree turn (here, a plurality of them around the ring 155) will prevent most of the water from falling down out of the cartridge and back into the interior volume of the bottle. One of the passages 140 (the first one) will typically empty, but the other passages 140', 140", 148, 148', etc., and space 157 and exit media zone 150 will typically stay full or nearly full. This way, when the user resumes drinking, water reaches the nozzle again quickly and easily. The preferred arrangement for water inlet into, and outlet from, cup 170 is schematically portrayed in Figures 6 and 7, wherein water enters only one passage (140) through one or more inlet holes, serpentine-flows through the rest of the passages all the way around the ring 155, and then exits from one or more outlet holes (156) out of the last passage (approximately 330 degrees away from the inlet in this embodiment). Alternatively, for flow distribution or other reasons, the water may enter the biocide cup at more than one passage, and may exit from more than one passage, and the path between the inlets and outlets may be controlled as desired by baffles. Also, the inlet passage(s) and outlet passage(s) may alternatively not be adjacent to each other at opposite ends of the path, but this is preferred for the orientation reasons described below. For convenience of illustration in cross-sectional Figure 5, an inlet 160 into the ring 155 is shown at the bottom of the figure and the outlet 156 is shown centered in space 157, but one may understand, from the above description and Figures 6 and 7 (wherein the inlet and outlet are indicated to be in adjacent passages at the beginning and end of the serpentine path, respectively), that this may not be the preferred or only relationship and location of inlet and outlet for the cup 170. The embodiment of Figures 5-7 preferably is not symmetrical about its central axis, but rather has an inlet into the biocide passages and an outlet from the dwell passages preferably on one side of the filter cartridge, the bottle and filter cartridge will preferably be held in a specific orientation during drinking. This will preferably place the inlet and outlet on the side that is downwards. This way, water flows properly into the ring 155. While Figure 5 show friction fits with o-ring seals between the cartridge and the cap 16, and between the various modular zones of the cartridge, it should be understood that alternative connections and seals may be used, for example, threaded connections, snap- together connections, or bayonet connections, with o-ring(s) and/or gasket(s).

Embodiment Three, Having Alternative Ring/Cup Structure and Exit Media Zone Figures 9 A, 9B, and 11-13 illustrate alternative cup and exit zone structures that are similar, but not identical, to the embodiment of Figures 5-7. Cartridge 300 comprises a pre- filter 330 (proximal side view in Figure 13), generally cup-shaped biocide media module 370 (end and side views in Figures 11 and 12), and radial-plus axial-flow exit media module 350. Pre-filter 330 may be threaded and screwed into cooperating threads on skirt 364 that extends distally from the cup module 370. Cup module 370 may be generally as described above for the embodiment of Figures 5 - 7, having ring 355, with a plurality of biocide media passages with optional dwell passages, positioned around the exit media zone 350. The biocide media passages (and optional dwell passages) are preferably adjacent axial, series-flow passages inside ring 355, wherein the ring 355 is the generally cylindrical double-wall of cup module 370. Describing the filter cartridge from its inlet to its outlet near the nozzle, the filter cartridge 300 features an inlet pre-filter 330, which may be a sediment filter, a one-micron cyst filter, or other pre- filter as desired, preferably friction fit and o-ring sealed into a skirt 364 extending distally from cup module 370. From filter 330, the liquid flows into cup module 370 by entering preferably one of the axial biocide passages 340 in the outer annular ring 355, for example, via inlet holes 360 shown in Figure 11. The liquid flows axially through passage 340, and then turns 180 degrees at the end of the passage to flow around a passage-separating wall 362, and flows in reverse through the adjacent passage 340'. From the passage 340', the liquid reverses again 180 degrees to the adjacent axial passage 340", and so forth. Thus, the liquid "zig-zags" "up and down" (proximally and distally) through the passages around the ring 355 (which are four in Figure 11 but may be other numbers), flowing in a serpentine path around the ring 355. At the end of a desired number of biocide passages selected and designed to provide adequate biocide media contact, passages in the ring optionally may be left empty as dwell chambers, also in series flow. After the liquid has flowed through preferably all of the ring, the liquid exits preferably radially from outlet(s) 356 into a radial space 357 at the bottom inside of the cup, which space 357 may also be a dwell chamber or may contain a media. Because the cup module 370 illustrated in Figure 11 has four passages and the inlets and outlets are located in passages 340 and 340'", respectively, outlet holes 356 in the fourth ("end") passage may be said to be generally 270 degrees from the inlet passage in terms of flow path. As discussed above for the second embodiment, one may see that this biocide module may be called a "cup" because of its bottom wall 358 and its concentric upending ring walls 365, 367 forming the ring for biocide and/or dwell passages. Also, as discussed above for the second embodiment, the inlet to and outlet from the biocide or dwell passages are preferably at or near the bottom of the cup, but embodiments may be designed with the inlet(s) and outlet(s) at different locations. The cup 370 having ring 355 may be said to feature multiple beds of media, preferably biocide media, separated by baffles or other walls to form a serpentine flow path having a plurality of flow reversals. Preferably, there are three or more reversals, and most preferably three or more 180 degree turns, resulting in a long, winding path through the ring 355 for enhanced biocide contact and mixing with the liquid. From outlet(s) 356, the liquid flows axially (proximally) into the exit media zone 350, which is preferably, in this embodiment, a substantially radial flow filter unit including multiple media. The outer layer 351 may be a silver-impregnated mesh, fibrous, or other material, which may surround carbon block 352 and help prevent live bacteria from entering and multiplying in the carbon block. The central cavity 353 of the carbon block 352 optionally be filled with additional media, such as granular metals removal media, extruded media, impregnated mesh or woven material, or other media. This exit media module may be configured to be an effective cyst removal system, such as for giardia and/or Cryptosporidium, preferably including less than or equal to 1 micron filtration capability in the carbon block. As in the second embodiment described above, exit media zone 350 is inserted into the central space of the cup 370 and therefore axially overlaps the ring 355. For example, the exit media zone 350 may extend almost fully into the cup 370, so that the biocide zone and post-biocide/biocide-removal zone are generally coaxial and axially overlapping for at least a part of their axial lengths, preferably so that the exit module overlaps greater than 1/2, and more preferably about 5/8 - 7/8, of the length of the biocide module. As discussed above, when the user is no longer drinking, the user will typically lower the bottle from the tipped-up position and release compression of the bottle. A limited amount of water will fall down out of the filter cartridge due to the preferred 180 degree turns (here, a plurality of them around the ring 355), which will prevent most of the water from falling down out of the cartridge and back into the interior volume of the bottle. One of the passages 340 (the first one) will typically empty, but the other passages and exit media zone 350 will typically stay full or nearly full. This way, when the user resumes drinking, water reaches the nozzle again quickly and easily. The preferred arrangement for water inlet into, and outlet from, cup 370 is that water enters only one passage (340), serpentine-flows through the rest of the passages all the way around the ring 355, and then exits from a single hole (356) out of the last passage (approximately 270 degrees away from the inlet in this embodiment). For convenience of illustration in cross-sectional Figures 9 A and B, an inlet 360 into the ring 355 is shown at the bottom of the figure and the outlet 356 is shown at the top of the figure, but one may understand, from the above description and Figures 11 and 12 (wherein the inlet and outlet are indicated to be in adjacent passages at the beginning and end of the serpentine path, respectively), that this may not be the preferred or only relationship and location of inlet(s) and outlet(s) for the cup 370. The embodiment of Figures 9A, 9B, 11, and 12 preferably is not symmetrical about its central axis, but rather has an inlet into the biocide passages and an outlet from the dwell passages preferably on one side of the filter cartridge, the bottle and filter cartridge will preferably be held in a specific orientation during drinking. This will preferably place the inlet and outlet on the side that is downwards. This way, water flows properly into the ring 355. While Figures 9 A, 9B, 11, and 12 show threaded connections with o-ring seals between the cartridge and the cap, and between the various modular zones of the cartridge, it should be understood that alternative connections and seals may be used, for example, friction-fit connections, snap-together connections, or bayonet connections, with o-ring(s) and/or gasket(s).

Embodiment Four Having Alternative Exit Media Zone Figure 10 schematically illustrates cartridge 300' without a bottle or other cooperating apparatus. The cup module 370 of this cartridge 300' is the biocide module of Figure 9A, 9B, 11, and 12, while the exit module 350' is a simpler radial flow unit, for example, a carbon block with a central return tube installed at the central axis of the carbon block. Not shown, but as understood by one of average skill in the art, screens, supports or walls may be included in this exit module 350' to control liquid flow.

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 broad scope of the following claims.