Liquid purification or separation – Particulate material type separator – e.g. – ion exchange or... – With spaced non-particulate separating means
Reexamination Certificate
1997-04-16
2001-09-18
Barry, Chester T. (Department: 1724)
Liquid purification or separation
Particulate material type separator, e.g., ion exchange or...
With spaced non-particulate separating means
C210S282000
Reexamination Certificate
active
06290848
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to filter cartridges for use in gravity-fed water treatment systems. In particular, this invention relates to a filter cartridge having novel filter media.
BACKGROUND OF THE INVENTION
Domestic water treatment devices are known in the art. Among these devices are self-contained systems which process water in batches. Examples of batch devices are pitchers/carafes and larger reservoirs where treated water is poured, for example, from a spigot. These self-contained systems typically have upper and lower chambers separated by a filter cartridge. They rely on gravity to force water from the upper chamber, through the cartridge, and into the lower chamber, thereby producing treated water.
The presence of unwanted and potentially harmful contaminants in water, especially drinking water, is of concern to many people. This concern creates a desire for water treatment devices in the home and elsewhere. Many water treatment devices and methods have been developed to remove or neutralize chemical and particulate contaminants. Some of these devices and methods incorporate chemically active materials to treat the water. For example, activated carbon is capable of removing the bad taste and odor from water as well as chlorine and other reactive chemicals. Ion exchange resins are useful for removing metal and other ions from water. However, no single material or chemical has been found that will remove all contaminants.
In addition to chemical and particulate contaminants, water often contains biological contaminants. These contaminants often can not be entirely removed by activated carbon, ion exchange resins, or other chemically active water purifiers. The biological contaminants may be susceptible to harsher chemical treatment, but such chemicals are, typically, themselves contaminants or can not be easily incorporated in gravity-fed treatment devices, especially those for household use. In addition to being resistant to removal by standard chemical means, many of these biological contaminants, such as protozoan cysts like cryptosporidium, are only a few microns in size.
Because of their small size and the relative unavailability of suitable chemical removal methods for these biological contaminants, a gravity-fed water treatment device which can remove protozoan cysts and still retain satisfactory flow rate has been very difficult to develop. Present devices which filter cysts out of water require pressurization, either from the tap or by manual pumping, to achieve a satisfactory flow rate. However, such devices are relatively complex and expensive, and in the case of manual pressurization systems, harder to operate. Thus, there is a need for a gravity-fed water treatment device that is capable of removing biological contaminants, including cysts like cryptosporidium, while providing an acceptable flow rate.
SUMMARY OF THE INVENTION
According to the present invention, a filter cartridge for a gravity-fed water treatment is provided. In one aspect of the invention, the filter cartridge includes a porous particulate filter that has an open upper end, a closed lower end, and sidewalls between the two ends. The porous particulate filter is sealed to a portion of the filter cartridge by a connecting member. Water is treated as the water flows into the open upper end and through the sidewalls of the porous particulate filter. Air within the filter, that is displaced by incoming water, flows out of the open upper end of the filter.
In another aspect of invention, the filter cartridge includes a porous particulate filter with sidewalls and an inlet. Granular media is contained within the sidewalls of the filter. Water is treated as it flows through the inlet of the filter, through the granular media, and radially outward through the sidewalls of the filter.
In a further aspect of the invention, the filter cartridge includes a porous particulate filter which includes glass fibers and a hydrophilic binder. The porous particulate filter is sealed to a portion of the filter cartridge by a connecting member. Water that is treated by the filter cartridge has greater than 99.95% of 3-5 micron cysts particles removed.
These and other advantages and features of novelty which characterize the invention are pointed out with particularity in the claims annexed hereto. However, for a better understanding of the invention and its advantages, reference should be made to the drawings which form a further part hereof, and to the accompanying descriptive matter in which there is illustrated and described a preferred embodiment of the invention.
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Product Literature for Purelt Water Filtration System from WTC Ecomaster Corporation (Minneapolis, Minnesota) (copyright 1995).
Product Literature for P{overscore (U)}R Hiker and P{overscore (U)}R Pioneer from Recovery Engineering, Inc. (Minneapolis, Minnesota) (on sale prior to Apr. 16, 1996).
Three color photographs of P{overscore (U)}R Pioneer from Recovery Engineering, Inc. (Minneapolis, Minnesota) (on sale prior to Apr. 16, 1996).
Product Literature for Pour-Thru Water Filter Pitcher System from Teledyne Water Pik (published prior to Apr. 16, 1997).
Scientific Products ,a catalog, pp. 914-916, 920, 922, 924, 928 (1994/1995 catalog).
The Fisher Catalog,pp. 725-728, 731-736 (published prior to Apr. 16, 1997).
Cole Parmer Catalog, 1995-1996, pp. ii-iii, 356-357, 362-363.
Product Literature for P{overscore (U)}R Water Microfilter, Recovery Engineering, Inc., (copyright 1993).
Cross-sectional figure of Water Microfilter shown in above P{overscore (U)}R product literature.
Emmons David J.
Tanner John D.
Barry Chester T.
Merchant & Gould P.C.
PUR Water Purification Products Inc.
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