Note: Descriptions are shown in the official language in which they were submitted.
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GRAVITY FEED BATCH FILTER .~ . ;.
WATER PURIFICATION CARTRIDGE HAVING MULTIPLE BEDS . ~.
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This invention relates to gravity feed water filtration
system~ and more particularly to drinking water purifiers and
deodorizer~ especially well adapted to reduce lead, chlorine,
aluminum and other 6ubstances from batches of water for home ~;
consumption in foods or beveragss.
The invention has many uses, such as in conjunc~ion
with coffea carafes, teapots, soup bowls, mugs, sauce pans,
large volume sto~age and dispensing containers, and the like.
For convenience of expression, all of these and similar
device~ will sometimes hereafter be called "carafes."
A growing number o~ impurities are recognized in tap
water which negatively affect its taste or healthfulness.
Lead and other heavy metals, hazardous chemicals, and noxious
trace compounds are frequently foùnd to contaminate drinking
~ater. Lead may cause mental retardation in children. Recent
new~ items have indicated a possibility that there may be a
link between aluminum and Alzheimer's Disease. In addition to
rnetals~ another contaminant o~ten found in drinking water is ;~
lorine which i~ added by state and local water works in
order to kill bacteria. Also, trace impurities often impart
an offensive taste or odor at the tap, which continues in
food~ or beverages made with such tap water. These problems
have been made worse by the increasing presencle of pollutants
and other contaminants in ground water supplies.
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One of the most troublesome problems currently facing the
nation is a removal of lead, chlorine, aluminum and other
substances in the drinking water. For example, among other
things, lead enters drinking water from solder used to join
copper tubing in home plumbing systems. The lead solder
cannot be removed from existing houses without imposing an
unacceptable C08t. The chlorine should not be eliminated from
the source water until immediately before consumption because
it i8 continuously necessary to kill bacteria in order to
prevent the spread of epidemic disease and other illness.
Therefore, it is important for some low cost means to be found
for reducing the lead, chlorine, aluminum and other
contaminants from drinking water before human consumption of
such water, or its use for foods or beverages.
Since it is highly likely that these and other
contaminants may be in existing drinking water used for home
consumption in foods or beverages for many years to come, it
is important to provide water filtration systems for use in
the home. Exemplary systems showing a water purifying
apparatus using gravity feed are found in U.S. Patents
4,306,971; 4,695,379; and 4,749,484. Other forms of water
purifying filters use line pressure to drive the water through
the filter. Exemplary filters of this type are shown in U.S.
Patents 4,686,037 and 4,504,389.
Thers are many times and places when filtered water is
desired at a location other than where the usual faucet filter ;~
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relying on water pressure is available. For example, one
might want a relatively small amount of filte~red water to make
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a cup of tea or coffee at the beach or on a patio. In such
locations, it is desirable to eliminate the need for water
pressure and to accomplish the filtration under a gravity
feed. Perhaps a person who is sensitive to a contaminant and
might wish to filter the contaminant from water while
traveling away from home. There may be any number of other
reasons why a person might wish to filter a relatively small
amount of water. ~ ~ ~
Patent 4,306,971 shows one form of gravity feed batch ~-
fllter means for relatively small quantities which may be used
for these purposes. Patent 4,749,484 provides an example of a
relatively large quantity gravity feed filtering system.
However, neither of these patents shows a filter which can
reduce contaminants such as lead, aluminum, and the like.
lS Therefore, there is a need for low cost filtering systems
which can filter these and similar contaminants from either
small or large batches of water used in foods or beverages.
Various filtration elements are commonly arranged in
interchangeable cartridges, which are replaceable upon their ;
exhau~tion and which are housed in a suitable apparatus that
might be attached to a tap water supply, for example. These
exlsting filtration cartridges depend upon water line pressure
to establish the feed rate at which the water flows through
the ~ilter. Therefore, if placed in a gravity feed system (no
line pressure), the water flow would likely be too slow to
provide a proper filtration since the dwell time for water
passing through the filter is quite important for proper
filtration. Accordingly, filters fed directly from a
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pressurized water line cannot necessarily be used in a gravity
feed device with optimum results. Moreover, most of these
filters are not designed to eliminate high levels of certain
contaminants, especially lead, aluminum, chlorine and the
like.
Another consideration is that certain contaminants may
tend to adversely affect the passage of water through a bed of
filter material and to reduce its useful lifespan. Thus,
there i5 also a need for a water filtration system with a
replaceable filtering cartridge which provides more complete ~ ;~
purification and which also offers an extended period of
operation. ~ ;
Accordingly, an object of this invention is to provide
new and improved low cost gravity feed water purification
~ystem~ which are capable of reducing contaminants--especially ~ ;
lead, aluminum, chlorine, and the like. A further object is
to provide ~uch systems with replaceable filter cartridges of
simple design and relatively inexpensive construction, which
enjoy an extended operational lifetime. Yet another object is
ao to provide such systems with replaceable cartridges which are
capable of being used in connection with existing coffee
makers and the like.
Another object of the invention is to provide both small
quantity and large quantity, gravity feed, batch filtering ;~
systems. ~; ;
These and other objects are accomplished, as are other ;~
advantages which will become more apparent, by preferred
embodiments of our invention which provide, for small quantity `~
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batch filtration, a receptacle which is somewhat reminiscent
of a funnel-shaped container into which fits a multi-stage `
water purification, filter cartridge. The system fits many
gravity feed devices, such as pots, carafes, etc. of coffee
makers, for example. The inventive large quantity, batch
~iltration, gravity feed system includes a two compartment,
preferably blow molded, container. An upper compartment
contain~i raw water, the lower filtered water. A filter
cartridge i~ located in a wall between the two compartments so
that water is filtered as it drains under gravity from the
upper into the lower container.
The cartxidge has one bed of a deionizing (ion exchange)
re~in or media followed by another bed of activated carbon
adsorption media, with a separation between them. The
eeparation is made of a particulate collecting material. ` `
Ionic contaminants, including lead, aluminum, and other ~`
metallic impurities, are removed as water passes through the
deionizing bed. The carbon bed eliminates organic and other
unpalatable constituents, as well as taste or odor which may
be introduced by the deionizing resins. A variety of pre- and
post-~iltration permeable, separation and particulate
collecting material or media may be employed to trap
particulate matter and also to control the flow pattern of
water through the cartridge so as to preserve the integrity of
the purification beds. The specifications of these permeable
materials are selected to provide a proper flow rate under
gravity.
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Preferred embodiments of the invention will be best
understood by reference to the following description of the
invention taken in conjunction with the accompanying drawings,
in which:
Fig. 1 is a schematic view of a prior drip coffee-making
appliance which utilized a gravity feed method;
Fig. 2 i8 a cross-sectional view of a first embodiment of ~ ~ ;
a batch purifying funnel-shaped container and multi-stage
water purification cartridge;
Fig. 3 is an elevation view of a modification of Fig. 2
whlch has a stepped wall to accommodate a variety of carafe
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sizes and an extended external collar to prevent filter
cartridge dislocation;
Fig. 4 is a longitudinal cross-sectional view of the
inventive filter cartridge;
Fig. 5 i3 a top plan view of the filter of Fig. 4; ;
Pig. 6 is a bottom plan view of the filter of Fig. 4;
Fig. 7 is a cross sectional internal view of a
modification to the coffee maker of Fig. 1 so as to ;~
accommodate the inventive cartridge within the coffee maker
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itself;
Fig. 8 i5 a perspective view of a large volume, batch
filterlng, gravity feed water system; and
Fig. 9 is a simplified vertical cross section of the
filter system of Fig. 8.
An exemplary prior art coffee-making appliance 10 is
shown in Fig. 1. The principal elements of appliance 10 are a :--
carafe 12, a water container 14, a heating element 16 upon -
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.:
which the carafe rests, any suitable and optional water
heating element (not shown), an output port 22, and a coffee
holding basket 24. Water is poured into the water container
14, where it may or may not be heated by an internal heating
element, depending upon whether the water must be preheated.
In this prior art appliance the water passes from container 14
through output port 22 and into the coffee basket 24, and then
through the ground coffee placed in the bottom of the coffee
basket 24. Coffee then falls under gravity and is collected
in the carafe 12. The heating element 16 keeps the coffee at
drinking temperature. This example of a common drip coffee
making appliance has no provision for filtering the water used
in the appliance.
Thi~ example of a coffee maker is only one of many
examples of when it may be desirable to have a relatively
small batch of filtered water. One can easily think of many
other examples such as water to make tea, soup, or the like.
A first characteristic of this kind of water usage is that
only a small amount of filtered water is needed, such as one-
to-twelve cups, for example.
Most batch filters are designed to provide relatively
large amounts of water. Therefore, the filters are relatively
large, may be awkward to handle, and probably require storage ;
between times when it is used to filter water. A second
~5 characteristic of relatively small quantities of filtered
water is that the user wishes to minimize the effort that must
be expended to filter the water. For example, a user might
not wish to spend a lot of time attaching a filter to a water
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tap. At one time, a carafe might be used to make the coffee,
and at another time the filtered water may be deposited into a -~
teapot or a sauce pan. Thus, the small batch filtering system ~;
should fit onto and be useful with any of many different sizes
and kinds of containers
According to one aspect of the invention a somewhat
funnel-shaped container 26 (Fig. 2) is provided with a support
member 28 from which a filter cartridge 30 may be hung. The ~;
angular flare (angle A) of the funnel shape is selected to fit
into and be supported by the open top of a carafe, teapot,
~mall sauce pan or the like so that it may be used with a
container having any suitable diameter simply by resting it on
the top of the container. While it is possible that the ;~
funnel-shaped container 26 may not fit all small sauce pans,
or the like, it does fit substantially all common, drip coffee ~ ~`
maker carafes and teapots.
More particularly, the funnel-shaped container 26 (Fig.
2) may or may not have circular cover 32 with an aperture 34 ;
for ingress of untreated water. If provided, preferably the
¢over would taper downwardly toward the aperture 34 to aid in
filling. The aperture 34 is here shown as directing the water
toward the side of the funnel 26 and away from thé cartridge
to prevent the water from striking the cartridge with the full
force of line pressure. The water poured on top 32 or ;~
directly into the funnel-shaped container 26 falls under
gravity through the funnel-shaped container and out the -
bottom, via the filter cartridge 30. The funnel-shape of the ~
container 26 provides a lower support section which rests on ~ ;
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the upper edge 36 of a carafe 12 or other suitable container.
The flare (angle A) is selected on a basis of the sizes of ~;
commercially available, drip coffee maker carafes, sauce pan
sizes, and the like.
The diameter of an opening 38 is selected to receive and
support the filter cartridge 30 which has a flared or beveled
~as seen at 39) upper edge 40 that fits into a tapered opening
with the top surface of filter 30 flush or below with the
surface of support member 28, which prevents drainage
problems. The upper flared edge 40 of the cartridge enables
it to rest on and be captured by the correspondingly flared
edge o~ the hole 38. The lower surface of the funnel has two
concentric collars 42, 44 which provide both mechanical
strength and alignment for the funnel-shaped container 26 and
mechanical stability for the filter 30 as it rests on its
upper edge 40 in the hole 38.
Preferably, all of the surfaces at the bottom of the
container 26 taper downwardly to insure proper drainage.
Thus, the water poured into container 26 enters and passes
through filter 30, emerging from the bottom 46 thereof, and
then on into the carafe 12, where it collects.
The construction of the preferred filter cartridge 30 is
shown in Figs. 2, and 4-6 and in U.S. Patent Application S.N.
07/284,256, filed December 14, 1988. A multi-stage water
purification cartridge incorporating the principles of the
invention comprises a cylindrical housing 50 having an upper ~-
inlet 52 and a lower outlet 54 in the upper and bottom ends of
the housings, as viewed in Figs. 2, 4, although other
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arrangements of inlet and outlet ports may also be provided.
The preferred housing 50 is non-porous and completely enclosed
except for inlet 52 and outlet 54, which may be factory sealed
to prevent tampering. A handle 55 is provided to facilitate a
removal of the filter.
Arranged along the length of the cartridge in a preferred ;
embodiment are a number of fibrous filtration and adsorption
media 56-60, the interfaces of which are perpendicular to the
longitudinal axis of the cylindrical housing. Included among
these filter media, and preferably located furthest upstream
(i.e., closest to the inlet 52), are one or more pre-
filtration permeable media disks or filters 56 which entrap `
particulate material. This filter or these filters 56 may be ;
disk~ made of a polyethylene, polyester, felt or other
~uitable fibrous material, having sufficiently small pores to
retain any selected particulate contaminants. A similar
permeable media filter 60 is preferably located at the
downstream end (i.e. near outlet 54), and is designed to trap
any additional particles.
A filter porosity which is smaller than 100 microns may
cause unacceptably slow performance when used with a qravity
feed water filtration system. That is, for gravity pressure
alone to drive a water filter, the separation media should be
very porous, preferably greater than 100 microns. For best
2S performance with the specified carbon granules and ion resin
and with acceptable filtration time, all of the filter pads
56; 58, 60 should have a porosity within the range of 150 to ;
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250 microns. This is more porous than the filter pads whichwork within water line pressure cartridges.
Between the pre- and post-filtration filters 56 and 60 is
a cavity which is divided into two beds or compartments 62 and
64 preferably of approximately equal volume. This compartment
separation i8 made by a permeable separation filter 58, which
may also be polyethylene, polyester, felt, or like fibrous
material, for example. In a preferred embodiment, the bed or
compartment 62 i8 located upstream of the separation filter 58
and contains a first purification bed of deionization resin.
The downstream bed or compartment 64 preferably contains a
~econd purification bed of granular activated carbon.
The preferred filter embodiment should be 50 percent
deionizing resin ~in bed 62) and 50 percent activated carbon
(in bed 64). However, the lead, aluminum, and other similar
mineral reducing properties of the resin are still acceptable
with as little as 20 percent deionizing resin in bed 62 and 80
percent carbon in bed 64. Also, a filter cartridge with 100
percent carbon and no resin is acceptable, but it does not
have the capability to remove aluminum, lead and similar
minerals. Additionally, an all carbon filter has a single bed
64 and does not have the center separation pad 58.
Preferably, the resin and carbon have the specifications set
! forth in co-pending application S.N. 07/284,256. An ;~
additional suitable and equivalent activated carbon is the
Calgon brand carbon Type Tog (20 X 50 mesh).
The flowing stream of water should preferably first pass
through the deionization resin bed and thereafter through the
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charcoal bed. This order is preferred so that the charcoal
bed will remove any odors or tastes which the resin may have
introduced. However, from a view point of the purification of
water, the reverse order (i.e. charcoal before resin) works
S egually well, unless one minds any odor or taste which the
resin may have introduced. In some instances, one might also
use a ~ingle bed which is a mixture of a deionization resin -~
and charcoal. In this embodiment the cost of the separating ~-
center filter 58 is saved; however, the operating life and
performance without filter 58 would be less than it would be
if center filter 58 is provided because filter 58 aids in
dispersing the water flow which reduces the likelihood of ~;
channeling.
The upper surface (Fig. 5) of the housing 50 has a
plurality of openings such as 66 in order to distribute the
inlet watex more uniformly and to accommodate the low pressure
of gravity feed. In like manner, the lower surface (Fig. 6)
has a plurality of openings 68 to also distribute the water
flow uniformly. Preferably the upper and lower openings are
offset with respect to each other. This distribution of the
openings tends to reduce channeling in the filter beds in -;
compartments 62, 64.
The same filters may find use in different kinds of ;~`
housfngs. For example, in Fig. 3, the housing structure 68
has a generally funnel shape with stepped regions in an area
70 to provide a plurality of graduated diameters which fit ;
into different size openings of carafes, tea cups, sauce pans, ;
or the like. It has been found that the structure 68 fits
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most presently used carafes when the angle A is in the range
of 25-45, with the preferred angle being 35. The diameters
of the steps in region 70 should be slightly less than the
diameters of the carafe openings which will receive the step.
This smaller diameter should be enough to allow air to escape
from the carafe.
The lower surface 71 of member 68 slopes downwardly at an
angle B in order to insure complete drainage. The pitch of
the 810pe (angle B) may be in any suitable range; however, a
range extending up to 10 is acceptable and 30 is preferred.
The external collar 42 extends downwardly beyond filter
cartridge 30 in order to aid in preventing the cartridge from
being dislodged.
The area 72 is a depression repeated on opposite sides of
the device 68 in order to provide a pair of handles for -
lifting it.
The device 68 receives a filter in the same manner that
has already been described in connection with Fig. 2.
The funnels shown at Fig. 2 and Fig. 3 are intended for
small batch water filtering before the water is poured into
opening 14 of the coffee maker at Fig. 1. Incorporating the
inventive cartridge inside a drip coffee maker would also be
advantageous. For such an internal (within the drip coffee
maker application) there may be a modification as shown in
Fig. 7 where the filter fits into the bottom of the water
compartment 73 of a drip coffee maker. The filter 50 drains
into a water reservoir 75 having a funnel-like bottom draining
into a rubber tube 77, or the like, which guides and directs
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the filtered water to a specific location iniide the drip
coffee making appliance. ~
A large volume, gravity feed, batch filtering device is ~-
shown in Figs. 8, 9.
Preferably, a double compartment, blow molded body 74
(Fig. 8) has upper and lower compartments 76, 78 separated by
an area 80 which includes a solid floor adapted to receive a
filter. A fill cap 82 is provided in the top of upper
compartment 76 and a spigot 84 is provided near the bottom of
the lower compartment of the body.
When the body 74 is placed on a refrigerator shelf, it
must be pushed back far enough to close the door, which
usually means that the spigot 84 is over a shelf and cannot be
used effectively. In order to draw water from the tank, it is
necessary to pull the container forward for the spigot to
extend beyond the shelf and to be over a cup. Therefore, a
handle 86 is provided to facilitate a sliding movement of the ; ;
body 74. also, the handle 86 facilitates a carrying of the
device when filled with water.
A vent tube 88 (Fig. 9), with a small hole 90, is formed
at a convenient location on the body 74 in order for air to
escape from the lower compartment 7~ as water flows under
gravity from the upper to the lower compartments. Preferably
the vent hole 90 is positioned on the side of tube 88 so as to
lessen the likelihood of contaminants falling into the tube
and entering the filtered water stored in compartment 78. A ~ -
suitable cap or cover (not shown) may slip over the top of
tube 88 to prevent spillage and to maintain cleanliness. A
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vent hole 91 is formed in the upper compartment 76 near the
top of the tube 88 to allow air to enter the upper compartment
as the water drains into the lower compartment. Preferably,
the vent 91 is in the raised portion of the container to be
above the water line and in an area which is within the
mechanical protection area, very near to, but not obstructed ;
by tube 88. Any suitable cap may be provided to maintain a
water tight seal while the container is being transported.
The cap 82 covers an opening 92 which is positioned above
the filter 50. The diameter of the opening 92 is large enough
for a person to reach into the upper compartment 76 and grasp
handle 55 in order to remove and replace the filter. An 0-
ring 94 seals the filter housing 50 against the body 74 to
prevent raw water from leaking around the filter and into the
lower compartment 78.
Since blow molded bottles have a considerable
flexibility, a rigid sleeve 96, with a snap catch lip 98 is
pressed into the opening between the compartments. This way,
the filter 50 has a firm and reliable seat to rest upon. The
bottom of the upper compartment tapers to the filter seat
formed by ~leeve 96 in order to fully drain the upper
compartment. Therefore, the sleeve 96 should not raise above
the level of the taper.
While the principles of the invention have been described -
in connection with the above embodiments, it is to be
understood that this description is made only by way of
example. It is not intended as a limitation on the scope of
the invention. Therefore, the appended claims are to be
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construed to include all equivalent structures falling within
the spirit and the scope of the invention.
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