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Description  |
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TECHNICAL FIELD
This invention relates to the field of treatment and improvement of potable
water, particularly for drinking. More particularly, it concerns a device
for point of delivery filtration of drinking water.
BACKGROUND OF THE INVENTION
Modern water supplies are subject to contamination from various agents,
both environmental and industrial in origin. Although public water
supplies are regulated by various governmental agencies, and are
ostensibly examined for compliance with standards of purity, such
standards are not always met. Occasionally, water supplies are
contaminated by illegal dumping of hazardous wastes, which may escape
detection if such occurrence falls between inspections. The result,
particularly in regions proximal to manufacturing enterprises or waste
disposal sites, is that drinking water is subject to contamination from
hazardous chemicals leached from the soil or deposited from smoke or
vapor. The presence of organic chemicals and minerals often causes, in
addition to disagreeable tastes, actual health hazards. As a result, the
bottled water industry has experienced nearly explosive growth over the
last several years.
As an alternative to foul-tasting, possibly harmful tap water, many
consumers have turned to services which provide bottled water in filtered
form, often sold as "natural spring water" or the like. The service
typically provides a free-standing water cooler, and delivers water in 5
or 3 gallon bottles periodically. The cooler, a device but little changed
over the last several decades, receives the bottle and chills and/or heats
a quantity of water, maintaining it at a suitable temperature for
dispensing. The cooler typically comprises a tall free-standing case
containing refrigeration means. The top surface generally has a circular
aperture surrounded by a cushioned ring for receiving and supporting the
water bottle. In use, a filled bottle is uncapped and inverted into the
cooler, so that the bottle comes to rest with the open mouth within the
cooler. A quantity of water pours from the bottle, filling a
water-receiving chamber immediately under the cooler's upper surface up to
a level which touches the neck of the bottle and halts the flow of water
out of the inverted bottle. The water may be cooled in this chamber, and
held until dispensed by activating the outlet.
The drawback to such a service, however, is expense. Bottled water must be
transported and delivered, whether by the consumer or by the service.
"Spring water" and the like is frequently transported considerable
distances. Also, reliance upon a service to deliver water leaves the
consumer at the mercy of the service's delivery schedule. Thus, a need
exists for a device to provide filtered, drinkable water while avoiding
the need to transport heavy bottles.
Frahm, U.S. Pat. No. 4,181,243 disclosed a device for filtering water which
comprises a receptacle having a spigot, wherein the spigot is provided
with a filter device having activated charcoal sandwiched between two
layers of filter paper held in a cylinder attached to the spigot inside
the receptacle. Although this device is capable of use with standard water
bottles, it is not easily adaptable to use with a conventional water
cooler.
Console et al, U.S. Pat. No. 4,145,291 disclosed a silver-impregnated
ceramic device for sterilizing, but not purifying, water stored in a tank
or dispenser for drinking.
Senyal, U.S. Pat. No. 2,335,458 disclosed a water filtration device for use
with bottled water comprising a long cylinder filled with activated
carbon, a filter, and a stopper and tube fitted within the bottleneck. In
operation, purifying and flocculating chemicals are added to the bottle
and the bottle inverted over the filter. After standing, a valve is
opened, and the water allowed to pass to the bottom of the cylinder
through a tube, after which it percolates upward through the activated
carbon, and is released into a receptacle for dispensing.
Hagg, U.S. Pat. No. 967,905 disclosed a water purifying device having a
cone-shaped baffle to prevent sediment from clogging the filtering medium.
Dick, U.S. Pat. No. 2,389,185 disclosed a filter device adapted for
attachment to the neck of a canteen or other water bottle, in combination
with a sterilizing agent (e.g., chlorine), and preferably a sedimenting
agent such as diatomaceous earth. The filter device allows troops to use
surface water, "no matter what its condition."
Jaye, U.S. Pat. No. 4,491,520 disclosed a water jug having an integral
filter cartridge. Water poured into the top of the container passes
through a disk containing activated charcoal sandwiched between sheets of
filter paper, and into a small reservoir adjacent to the spigot.
Paddock, U.S. Pat. No. 444,013 disclosed a water pitcher with an internal
filter for ice water. The filter comprised a cylinder having a filter
medium at the bottom, and supported on the pitcher base.
Miller, U.S. Pat. No. 4,764,274 disclosed a water filter for use with a
pitcher or water bottle, comprising a layer of activated carbon sandwiched
between two filter pads, and encased in a frustro-conical housing.
Gelman et al, U.S. Pat. No. 4,025,438 disclosed a water filter unit for
attachment to a water faucet, comprising an activated carbon layer
supported on a micron filter, and covered with a filter having a pore size
larger than the supporting filter but smaller than the carbon particle
size.
Tyson et al, U.S. Pat. No. 4,024,991 disclosed a device adapted for
positioning within a bottle neck to impart silver ions to water, thereby
preventing bacterial contamination of the water.
White, U.S. Pat. No. 2,502,298 disclosed a device for filtering water from
one bottle into another bottle, comprising a stand, a funnel, where the
stand and funnel are dimensioned to seal together and prevent the funnel
from overflowing during the filtering operation.
Behrman, U.S. Pat. No. 4,094,779 disclosed a device for filtering water
from one bottle into another bottle, comprising a stand, a funnel
containing a filter medium (e.g., activated carbon) sandwiched between two
layers of filter paper, and valves for regulating the water flow rate out
of the upper bottle, and from the funnel into the receiving bottle.
Van Eweyk, U.S. Pat. No. 2,167,225 disclosed a device for filtering water
from one bottle into another bottle, comprising a cylinder capable of
supporting a full bottle, filled with a filter medium (e g.,
silver-impregnated partially exhausted zeolite). The cylinder is screwed
onto the empty receiving bottle, and the filled supply bottle is inverted
into the open mouth of the filter cylinder.
Hankammer, U.S. Pat. No. 4,623,457 disclosed another water pitcher having a
filter medium encased in the lid portion of the pitcher. Water is added to
the pitcher through the lid, where it is filtered and passed to the main
body of the pitcher until it is dispensed.
DISCLOSURE OF THE INVENTION
We have now invented a water purifying filter device capable of removing
chlorine, organic chemicals, particulates, and bacteria from potable
water. This device may be used with a conventional water cooler and is
configured for insertion into the water cooler's bottle-receiving aperture
which is typically located on the top surface of the cooler. In use, the
device of this invention is placed in the aperture and then a filled water
bottle is inverted with its neck placed in the device. The device provides
filtration of the water from the inverted bottle at a flow rate
sufficiently high that users will not notice a substantial restriction in
flow as compared to the flow of water normally observed from bottled water
systems. In practice, the consumer may fill a standard 5 or 3 gallon water
bottle with ordinary tap water: after passage through the filter device of
the invention, the water is of a quality equal or superior to that of
commercial bottled water or spring water.
The device comprises a cylinder having an open top end and a closed but
porous bottom end. The open top end of the cylinder is formed into an
outwardly flaring flange (i.e., lip or shoulder). The cylinder and this
outwardly flared flange are sized to receive the neck of a water bottle
and to provide a rest for the body of the bottle. The flange is capable of
supporting the weight of a filled water bottle. At the lower end of the
cylinder is provided a water permeable filter medium comprising activated
carbon impregnated with silver, sandwiched between two micron filter pads.
The entire cylinder (except for the flange) fits within the bottle
receiving aperture and water receiving chamber of a conventional water
cooler, and provides sufficient filter surface area to allow high flow
rates through the filter medium. The length of the cylinder and the height
of the flange are such that when a bottle is inverted into the device and
water flows through the filter it enters the water receiving chamber and
rises to level which meets and contacts the open end of the water bottle
inverted into the device.
BRIEF DESCRIPTION OF THE DRAWINGS
In this description of the invention reference will be made to the
accompanying drawings in which:
FIG. 1 is an exploded view of one embodiment of the invention;
FIG. 2 is a side view of the device of FIG. 1 in partial cutaway;
FIG. 3 is a cutaway view of a device of FIG. 1 in place in a conventional
water cooler;
FIG. 4 is a horizontal cross-sectional view of a device of FIG. 1 taken so
as to provide top view details of its water distribution baffle;
FIG. 5 is a partially cut away top view of a top filter-retainer used in
the device of FIG. 1;
FIG. 6 is a partially cut away top view of a bottom filter-retainer used in
the device of FIG. 1; and
FIG. 7 is an expanded scale vertical cross-sectional view of the lower
portion of the device of FIG. 1 taken so as to provide details of its
construction.
DETAILED DESCRIPTION AND PREFERRED EMBODIMENTS
A presently preferred embodiment of the device of this invention is
depicted in FIGS. 1 and 2 and shown in operation in FIG. 3. Details of the
device of FIGS. 1 and 2 are provided in FIGS. 4 through 7. The device 1
comprises a generally cylindrical canister body 10 having a substantially
rigid flange 12 at one end 14. This end 14 carrying the flange 12 is open.
The flange 12 is outwardly flaring and is capable of supporting the weight
of the entire device when filled with water, as well as the weight of a
filled 5 gallon water bottle.
As can be seen in FIG. 3, canister body 10 has a diameter which will fit
within the bottle aperture of a water cooler. The flange 12 has an
exterior diameter which exceeds the diameter of the cooler bottle aperture
such that, in use, the lower surface of the flange engages and rests upon
the solid top surface of the cooler surrounding the water cooler bottle
aperture. The body and flange are formed from nontoxic materials suitable
for use with potable water, typically inert castable plastics such as
polyvinylchloride, polypropylene, polyethylene, ABS, and the like.
The lower end 16 of the canister body 10 contains the filter assembly. This
includes an upper filter-retainer 20 and a lower filter-retainer 26. These
filter-retainers are porous and are sealably joined to the inside of the
canister in a spaced parallel configuration so as to define a cavity
between them. This cavity 34 houses a bed of filter medium 35 as detailed
in FIG. 2. The upper filter-retainer 20 includes a filter sheet 22 having
a thickness of about 0.10" and capable of retaining micron size particles
supported by a supporting member 24. The periphery of support 24 can be
formed into a sealing ring 25. This ring is sized to be glued or otherwise
fastened to the interior of canister 10 so as to prevent water from
passing around the filter instead of passing through it. Canister 10 may
be provided with an internal flange 38 to facilitate proper positioning
and attachment of the upper filter-retainer 20. Support 24 as shown
includes a plurality of radial ribs 21, 21', etc joined by annular ribs 23
and 23'.
Filter sheet 22 is preferably a polyester-filled pad. Supporting member 24
is also formed from materials suitable for use with potable water, such as
the plastics described above as suitable for forming the body and flange
of the device. The supporting member 24 may be die-cast, injection molded,
and the like. The support member configuration depicted in FIG. 5 is
merely representative. It will be apparent to one of ordinary skill in the
art that other configurations capable of supporting a micron filter pad
may be substituted.
The filter sheet 22 is attached to support 24 by any suitable means,
typically be bonding such as with the use of FDA-acceptable adhesives, or
preferably by use of ultrasonic bonding, for example using a Branson Model
Series 8400 ultrasonic welding machine (Branson Ultrasonics Corp., Danbury
CT).
Lower filter-retainer 26 is similar to and preferably substantially
identical to upper filter-retainer 20 in terms of materials of
construction and the like. It includes filter sheet 28 and support 30 made
up of radial ribs 27, 27', etc., and annular ribs 29 and 29' and an outer
annular rib which may, if desired include seal ring positioning flange 31
as detailed in FIG. 6.
The filter sheet 28 may be of the same material as the filter sheet 22 in
upper filter 20, and may be bonded to lower support member 30 in the same
manner as upper filter sheet 22 is bonded to upper support 24. As shown in
FIG. 7, lower support member 30 may have a positioning flange 31 to insure
that the lower retaining means is positioned at the bottom of canister 10
and forms a water-tight seal therewith. Canister 10 may additionally be
provided with a ledge 37 to insure that lower support member 30 seats and
seals properly against the canister wall. As shown in FIG. 7, the inner
surface of canister 10 may be flared outward below flange 38 in order to
facilitate insertion of upper filter-retainer 20. As also shown in FIGS. 2
and 7, the outer surface of canister 10 may be tapered inward toward the
lower end to facilitate insertion into a water cooler reservoir. The
device illustrated in FIGS. 2 and 7 tapers from the flange 12 to the
bottom opening 16. Such taper also aids in fabrication of the device by
injection molding.
The volume 34 defined by filter-retainer assemblies 20 and 26 is occupied
by a silver-impregnated activated carbon filter medium 35. Medium 35 is
most easily inserted after upper assembly 20 has been put in place, and
before lower assembly 26 is attached, with the canister body 10 inverted.
Medium 35 preferably comprises a granular activated carbon having a
particle size of about 20.times.50 U.S. standard sieve, and has metallic
silver chemically plated in ratios of about 0.026% to about 1.05%.
Suitable media are available commercially, for example under the name
Hygene Mark I, Hygene Mark II, and the like (Ionics, Inc., Bridgeville,
Pa.). The quantity of silver employed must be sufficient to render medium
35 bacteriostatic. The granule size and packing density of medium 35 are
adjusted in concert with the porosity of filters 22 and 28 in order to
insure a flow rate of at least 0.03 oz/sec through the filter.
The device may optionally be provided with a baffle 32 having perforations
33 positioned to distribute water evenly over the upper filter-retainer. A
suitable representative baffle configuration is depicted in FIG. 4. The
baffle 32 may be formed as an integral part of canister 10, e.g., by
injection molding, or may be formed separately and fastened into position
in the same manner as the two retainers 20 and 26. If baffle 32 is formed
as an integral part of canister 10, the lower portion of the baffle may
conveniently serve as flange 38. Alternatively, if provided separately,
baffle 32 may be bonded to the upper surface of flange 38, while
filter-retainer 20 is bonded to the lower surface of the flange, thus
allowing space between baffle 32 and filter 22.
Typically, the device of this invention is fabricated as follows. First,
canister 10 is inverted. The upper filter-retainer 20 is then inserted
into canister 10, and is fixed with adhesive or ultrasonic bonding to
insure a water-tight seal. Then filter medium 35 is added, and the lower
filter-retainer retainer 26 is bonded in place, forming a water tight seal
around the ring.
FIG. 3 depicts a device of the invention 1 positioned in a conventional
water cooler 2, for example a Model EBAHC-1 Hot and Cold Cooler (Elkay
Mfgr. Co., Oak Brook, Ill.), and supporting a water bottle 3. Water cooler
2 has an upper surface 40 including a bottle-receiving aperture 42 and a
water reservoir 44, frequently surrounded by collar 46. Collar 46 is
typically provided to support bottle 3, and is usually permanently
attached to surface 40. Flange 12 is preferably dimensioned to bypass
collar 46, and to rest directly on upper surface 40. Flange 12 supports
bottle 3 and suspends canister 12 within reservoir 44.
In operation, canister 10 is inserted into reservoir 44 until flange 12
comes to rest on upper surface 40. A filled water bottle 3, typically 3
gallon or 5 gallon, is then opened and inverted into aperture 14 and
canister 10. Water flows from bottle 3 into the upper portion of canister
10 and is diverted by baffle 32 through perforations 33 into space 48
between baffle 32 and retainer-filter 20. Water then flows through upper
filter 22, which retains all particles larger than micron size, and into
medium 35, which filters absorbable organic chemicals, halogens, and
microbes from the water. The amount of medium 35 employed is determined by
its ability to remove these impurities during passage of the water. The
water then passes through lower filter 28 and into reservoir 44 until the
water level within the reservoir is slightly above the bottle opening.
Distance a and distance b (FIG. 2) are determined so that (1) there is
sufficient space for medium 35, and (2) there is sufficient volume 38
above baffle 32 to provide a water head guaranteeing adequate flow rate.
When properly adjusted, the flow rate provided with the device in place
will be such that normal withdrawal of water from the cooler will not be
reduced. Thus, a flow rate through the filter device equal to the spigot
flow rate will be adequate. Higher flow rates are also acceptable, as long
as the water is retained in the filter medium for a period of time
sufficient to remove absorbable organic chemicals, chlorine, and microbes.
This flow rate, however, neglects the presence of water in the reservoir.
As water coolers are typically not operated continuously, it is acceptable
to reduce the filter flow rate and rely on water within the reservoir, so
long as the filter flow rate is sufficient to replenish the reservoir
before it is emptied in normal use. A filter flow rate of 0.03 ounces per
second (oz/sec) or greater is an acceptable filter flow rate. A flow rate
of about 0.3 oz/sec or greater is presently preferred.
Water cooler reservoirs have fairly similar dimensions, thus allowing the
device of the invention to be suitable for the majority of coolers
commercially available. However, in the event that a particular cooler
reservoir is of insufficient depth, one may insert a spacing ring (not
shown) between the flange 12 and upper surface 40 to raise the device in
order to clear the lower surface of the reservoir. The spacing ring may be
of any suitable material, and is preferably shaped to accommodate any
collar 46 which may be present.
It will be appreciated that the device of this invention will have the
property of raising the level of water within the cooler reservoir. This
is because the water level is defined by the level to which the lower rim
surface Of the inverted bottle extends. The present device is placed
between the bottle and the cooler and raises the bottle (and thus the
water level) by an amount related to the height of the outwardly flaring
flange. Therefore the effective height of the flange should be not greater
than about 3" so as to avoid any problems with overflow from the cooler
water reservoir 44. The term "effective height" refers to the distance
that the device raises the water level. Depending upon the internal taper
or bevel of the bottle receiving flange end of the device, the effective
height of the device may be substantially less than the actual height of
the flange.
Variations of the above-described device will be apparent to those skilled
in the art, and are to be considered within the scope of the claimed
invention.
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