Water treatment cartridge and base

A water treatment unit includes a base and a disposable, plug-in cartridge. The cartridge contains a pair of hollow cylindrical, porous, solid water treatment elements designed to treat water flowing radially through their walls. The cylindrical elements are mounted so as to act in parallel, thereby achieving the advantages of a long, thin-walled element in a compact configuration.

TECHNICAL FIELD 
This invention relates to apparatus for treating water. More particularly, 
it relates to water filtration apparatus in the form of a disposable 
cartridge and a base therefor. 
BACKGROUND ART 
The use of disposable water treatment elements such as filters is 
well-known. One type of such filter is in the form of a solid porous 
cylinder having a hollow center. When such an element is employed, the 
water or other liquid to be treated or filtered flows radially through the 
wall of the cylinder between its exterior and its hollow core. Examples of 
such an element are the well-known ceramic filter and the extruded solid 
activated carbon filters made by the method and apparatus disclosed in 
Koslow U.S. Pat. Nos. 5,189,092; 5,249,948; and 5,331,037. See also the 
co-pending U.S. patent application Ser. No. 08/607,294 filed Feb. 26, 1996 
of Koslow, et al (pending). 
It is well-known that the most efficient filtration is achieved with a 
relatively long but thin-walled filter element. For example, a long and 
thin cylinder will always display a lower pressure drop than a short and 
fat cylinder of the same volume of active ingredient, both because the 
flow area is larger and the thickness of the medium through which the 
fluid flows is reduced. However, this presents a problem, especially when 
the element is employed in a domestic water filtration unit such as might 
be maintained at a kitchen or bathroom sink. In order to achieve the 
desired flow volume, a long and ungainly filter element would be required. 
A second problem is that the changing of filter elements in the 
conventional domestic filter housing is a messy job often requiring tools 
and proving very difficult to open because of the large diameter pressure 
vessels with large threads and compression gaskets. Entirely new problems 
of space and convenience would emerge when using an exceptionally long 
filter element. Accordingly, it is a primary object of the present 
invention to provide an improved liquid treating apparatus and, more 
specifically, a water filtration apparatus which has the desirable 
characteristics of a thin-walled, hollow, cylindrical filter element but 
in a compact configuration. Another object is to provide such an apparatus 
wherein the filter element may be easily replaced and disposed of with a 
minimum of mess and water spillage. Another object is to provide such an 
apparatus wherein the filter elements are so arrayed as to present a 
relatively flat configuration more readily handled and stored than the 
usual prior art round array. Other objects, features, and advantages will 
become apparent from the following description and appended claims. 
DISCLOSURE OF INVENTION 
In accordance with the present invention, the desirable long and 
thin-walled solid porous hollow cylinder is reconfigured as two or more 
short cylindrical portions which are operated in a parallel fashion as a 
flat array. In this way, the efficiency and water volume is maintained but 
in a much more compact form. The filter elements are housed within a 
disposable cartridge which plugs into a base member from which it can be 
easily removed.

BEST MODE FOR CARRYING OUT THE INVENTION 
The invention comprises a base member and a filter cartridge which is 
insertable into the base member. The cartridge is illustrated by FIGS. 1-7 
and the base by FIGS. 8-10. Reference may also be had to FIG. 12 which 
illustrates the cartridge 10 mounted in the base 12. 
Cartridge 
The cartridge 10 comprises a main housing of substantially rectangular 
cross-section comprising a front wall 14, a rear wall 16, left 18 and 
right 20 side walls, and a top wall 22 (FIG. 12). A stiffening web 24 
extends downwardly from top wall 22 between front wall 14 and rear wall 
16. The stiffening web performs the important function of preventing 
deformation of the housing when under full line water pressure. This 
allows for a relatively flat housing, as opposed to the cylindrical 
housings of the prior art. A cartridge base 26 closes the bottom of the 
housing. It is in the form of a base plate 28 from which extend a hollow 
water inlet stud 30 and a similar water outlet stud 32. The studs 30, 32 
have axial bores 34, 36. They have circumferential grooves on their outer 
surfaces for the retention of rubber O-rings 38. 
The top surface of base plate 28 is illustrated in FIG. 5. It carries a 
raised dam 40 which is substantially rectangular and encompasses a bore 36 
which extends through the water outlet stud 32. However, one corner is 
provided with an offset 42 which leaves the bore 34 of the water inlet 
stud 30 on the outside of the dam. Also carried on the bottom surface of 
the cartridge base plate 28 is a centrally positioned key 44 having a 
generally arrow shaped cross-section as seen in FIG. 2 whereby the barbs 
of the arrow define a pair of spaced detents. On either side of the key 44 
is a semi-cylindrical socket 46, 48 whose function will be described 
hereafter. 
Mounted on the top of the dam 40 is a filter support plate 50 illustrated 
most clearly in FIGS. 6 and 7. Filter support plate 50 is substantially 
rectangular so as to fit snugly within the housing walls of the cartridge 
10 as illustrated in FIG. 12. Depending from the bottom surface of the 
filter support plate 50 is an alignment ring 52. The alignment ring 52 has 
essentially the same configuration as the dam 40 and is dimensioned to fit 
within the dam. Extending upwardly from the top surface of the filter 
support plate 50 are a pair of circular sockets 54, 56. Centrally located 
within the socket 54 is a frustoconical alignment stud 58 having a central 
passage 60 therethrough. A similar alignment stud 62 within the socket 56 
defines a similar passage 64. Positioned within the socket 54 is the 
bottom end of a solid porous hollow cylindrical filter element 66. The 
filter element 66 includes a central bore 68 which extends alongs its 
longitudinal axis and its upper end is rendered impervious to flow by a 
suitable cap disk 70. Similarly mounted within the socket 56 is a similar 
filter element 72 which also has an axial bore 74 and a cap disk 76. In at 
least one actual embodiment, the preferred actual outer diameter of each 
filter element does not exceed approximately 1.75 inches to assure a fiat 
array of relatively small size. 
The illustrated cylindrical filter elements are discrete units. However, 
they could be extruded as interconnected cylinders--two cylinders 
connected by a web, for example. As used in the accompanying claims, the 
terms "at least two" and "a plurality" are to be construed as including 
such connected elements. 
Base 
The base member 12 is illustrated in FIGS. 8-12. It is in the form of a 
substantially rectangular frame including a front wall 78, rear wall 80, 
left end wall 82, and a right end wall 84. Extending between the four 
walls is a depressed floor 86. An interior transverse wall 88 extends 
between front wall 78 and rear wall 80 and centrally positioned along this 
wall is a circular socket 90. At the base of the socket 90 is a water 
outlet passage 92 which extends downwardly through a hose attachment 
member 94 which depends from the floor 86. A similar socket 96 is 
positioned in the lower right corner of the base member 12, as viewed in 
FIG. 8, and includes a similar water inlet passage 98 which extends 
through a similar hose attachment member 100 also depending from the floor 
86. Adding support to the floor 86 is a depending transfer support wall 
102 extending downwardly from the floor 86. 
Centrally positioned within the base member 12 and extending upwardly from 
the floor 86 are a pair of substantially cubical alignment studs 104, 106. 
A pair of parallel slots (not shown) in the floor 86 receive the legs of a 
U-shaped spring clip 108. The upper edges of the spring clip legs are bent 
downwardly to form hooks 110 which form a latch. The legs of the spring 
clip 108 lie adjacent the studs 104, 106 and the spring clip is secured by 
means of screws or pins 112 which extend into the alignment studs 104, 
106. 
Extending upwardly from the floor 86 and on either side of the spring clip 
108 are cylindrical posts 114, 116. Encircling each post is a helical 
compression spring 118. A shaft extends through the right end wall 84 and 
terminates in the transverse wall 88. The shaft includes a central portion 
120 which is elliptical in cross-section and lies within the legs of the 
spring clip 108 as shown in FIG. 10. An external lever 122 is mounted to 
the end of the shaft to manually rotate it. 
Operation 
The apparatus of this invention comprises two separate and distinct units. 
The base member 12 is mounted to, or rests upon, a flat supporting surface 
such as a counter top. A water inlet hose 124 may be connected to the hose 
attachment member 100 and a water delivery hose 126 may be connected to 
the hose attachment member 94 as shown in FIG. 12. The separate cartridge 
member 10 is connected to the base member by inserting the studs 30, 32 
into the sockets 90, 96. As these are inserted, the semi-cylindrical 
sockets 46, 48 depending from the cartridge 10 engage and depress the 
helical springs 118 carried by the posts 114, 116. As these springs are 
depressed, the key 44 enters within the legs of the spring clip 108, 
pushing them apart until the hooks 110 engage the upper surfaces of the 
detent barbs formed by the arrow shaped cross-section of the key 44, 
thereby locking the cartridge in position on the base member as 
illustrated in FIG. 12. The same springs aid the removal of the cartridge 
member 10 from the base member. 
The operation of the unit will be best understood by referring to FIG. 12 
wherein the water flow is illustrated by dashed lines and arrows. As shown 
therein, water flows into the base member and flows via socket 96 and 
water inlet stud 30 into the space surrounding the dam 40. It flows 
upwardly through the "missing" corner of the filter support plate 50 (FIG. 
6) and fills the housing, forming a first volume surrounding the filter 
elements 66, 72. The stiffening web 24 extends only partially along the 
length of the cartridge housing and does not impede water flow. The water 
passes radially through the walls of the filter elements and into the 
bores 68, 74 passing downwardly through the passages 60, 64 in the filter 
support plate 50 into the region surrounded by the dam 40. The combined 
volume of the bores 68, 74 forms a second volume. The water then flows via 
water outlet stud 32 and the hose attachment member 94 and exits through 
the water outlet hose 126. The two filter elements receive water 
simultaneously. In this respect, they function identically to a single 
long filter element but acquire the mechanical advantages of a much 
smaller unit. It may be likened to a single element being cut into 
multiple sections with sections thereafter being operated in "parallel". 
This is of particular advantage in the case of solid activated carbon 
filters as referenced above. These filters, if not long and thin, are 
characterized by a high .DELTA.P. 
When it is desired to change the cartridge and substitute a new one, it is 
merely necessary to rotate the lever 122 by 90.degree.. This rotates the 
elliptical portion 120 of the shaft and forces the hooks 110 apart as 
illustrated in FIG. 11. This releases the key 44 on the cartridge and 
permits it to be detached whereupon a new cartridge may be inserted. 
It is believed that the many advantages of this invention will now be 
apparent to those skilled in the art. It will also be apparent that a 
number of variations and modifications may be made therein without 
departing from its spirit and scope. Accordingly, the foregoing 
description is to be construed as illustrative only, rather than limiting. 
This invention is limited only by the scope of the following claims.