Water dispenser abstract
An automatic filter shutoff device removably connected to a water
container and in fluid communication with a water dispenser, which
is adapted to monitor water dispensing and disable dispensing after
a predetermined amount of water usage. The device includes a housing
containing a water filter and removably connected to the water container;
a monitoring and disabling mechanism having a shutoff apparatus
moveable between first and second locations, the first location
being one in which water dispensing is monitored by the mechanism,
and the second location being one in which the mechanism is placed
in an interfering position with the connection between the housing
and the water container. The shutoff apparatus automatically moves
into the second location after the predetermined amount of water
usage has occurred, and without interrupting water dispensing from
the then-connected water container, so that the used filter shutoff
device must be replaced in order to reestablish connection to a
successive water container. A filter mechanism is also provided
with a housing containing a water filter and having a throat removably
connected to a bottled water container. The throat is a restricted
orifice sized to permit a volumetric flow rate of not greater than
about 7500 ml./min. of water passage during inversion of the water
container and initial flow from the container into the filter. A
plurality of vent holes are located in an upper surface of the filter
housing and sized to permit air from the filter to escape into the
water container and allow continuous water flow from the container
into the filter. When a new water container is connected to the
housing, the water level within the filter does not reach the vent
holes in the filter housing.
Water dispenser claims
We claim:
1. An automatic filter shutoff device removably connected to a
water container and in fluid communication with a water dispenser,
the device being adapted to monitor water dispensing and disable
dispensing after a predetermined amount of water usage, comprising:
a housing containing a water filter and removably connected to
the water container;
a monitoring and disabling mechanism having a shutoff apparatus
moveable between first and second locations, the first location
being one in which water dispensing is monitored by the mechanism,
and the second location being one in which the mechanism is placed
in an interfering position with the connection between the housing
and the water container;
wherein the shutoff apparatus automatically moves into the second
location after the predetermined amount of water usage has occurred,
and without interrupting water dispensing from the then-connected
water container, so that the used filter shutoff device must be
replaced in order to reestablish connection to a successive water
container.
2. The automatic filter shutoff device of claim 1 wherein the
predetermined amount of water usage generally corresponds to the
useable life of the filter.
3. The automatic filter shutoff device of claim 1 wherein the
device is adjustable so that dispensing may be disabled after differing
amounts of water usage.
4. The automatic filter shutoff device of claim 3 wherein the
monitoring and disabling mechanism comprises a visual indication
to facilitate adjusting of the mechanism for differing water usages.
5. The automatic filter shutoff device of claim 1 wherein the
shutoff apparatus comprises a plunger whose vertical height may
be varied, and wherein the second location comprises a position
in which the plunger obstructs the connection of the filter housing
and the water container.
6. The automatic filter shutoff device of claim 1 wherein the
monitoring and disabling mechanism further comprises a filter cap
with a downwardly depending leg having a locking window engageable
with a locking tab located on the shutoff apparatus.
7. The automatic filter shutoff device of claim 6 wherein the
engaging surfaces of the locking tab and locking window are angled
to facilitate entry of the tab within the window.
8. The automatic filter shutoff device of claim 6 wherein the
engaging surfaces of the locking tab and locking window are angled
to prevent disengagement of the tab from the window.
9. The automatic filter shutoff device of claim 1 wherein the
plunger has a top surface with a throat opening and annular side
walls with spaced openings, and wherein the surface area of the
orifice is approximately equal to the surface area of the side openings.
10. The automatic filter shutoff device of claim 1 wherein the
monitoring and disabling mechanism further comprises a filter cap
mounting radially disposed, opposing teeth, and the shutoff apparatus
comprises a rotary indexer having a radially protruding tab iteratively
communicating with the teeth, and wherein the rotary indexer monitors
water dispensing by tracking the number of water containers used
during dispensing.
11. The automatic filter shutoff device of claim 1 wherein the
monitoring and disabling mechanism comprises a NSF-compliant performance
indication device.
12. The automatic filter shutoff device of claim 1 wherein a visual
indicator is provided to advise the user that the filter is nearing
the end of its useful life.
13. The automatic filter shutoff device of claim 12 wherein the
visual indicator comprises a color band located on an outer surface
of the filtering and disabling mechanism.
14. The automatic filter shutoff device of claim 1 wherein the
monitoring and disabling mechanism comprises a helical-shaped spring.
15. The automatic filter shutoff device of claim 1 wherein the
monitoring and disabling mechanism comprises a rotary index engageable
with teeth having a number corresponding to the predetermined amount
of water usage.
16. A filter mechanism connected to a bottled water container adapted
to be inverted and placed in fluid communication with a water dispenser,
comprising:
a housing containing a water filter with a throat removably connected
to the bottled water container, the throat comprising a restricted
orifice sized to permit a volumetric flow rate of not greater than
about 7500 ml./min. of water passage during inversion of the water
container and initial flow from the container into the filter;
a plurality of vent holes located in an upper surface of the filter
housing and sized to permit air from the filter to escape into the
water container and allow continuous water flow from the container
into the filter;
wherein when a new water container is connected to the housing,
the water level within the filter does not reach the vent holes
in the filter housing.
17. The filter mechanism of claim 16 further comprising a monitoring
and disabling mechanism having a shutoff apparatus moveable between
first and second locations, the first location being one in which
water dispensing is monitored by the mechanism, and the second location
being one in which the mechanism is placed in an interfering position
with the connection between the housing and the water container,
wherein the shutoff apparatus automatically moves into the second
location after the predetermined amount of water usage has occurred,
and without interrupting water dispensing from the then-connected
water container, so that the filter shutoff device may not be connected
to a successive water container.
18. The filter mechanism of claim 16 wherein the restricted orifice
has a diameter of less than about one inch.
19. The filter mechanism of claim 16 wherein the restricted orifice
has a diameter of about 3/4 inches.
Water dispenser description
BACKGROUND OF THE INVENTION
The present invention generally relates to the dispensing of filtered,
bottled water. More specifically, the invention relates to a shutoff
device that monitors the number of bottles used and then disables
further use of the filter when the filter has reached the end of
its useful life. The device can also provide an early warning signal
to the user that the filter is nearing the end of its useful life.
Self-contained filters for removing unwanted minerals and chemicals
such as chlorine have become increasingly popular with bottled water
users. These filters may be threadably attached or otherwise connected
to the opening of a bottled water container, or may be contained
within the water dispenser unit. Various devices are also known
for monitoring water flow and then interrupting water flow after
a predetermined use.
Some prior art devices have provided techniques for opening a pressure
vessel containing a carbon filter used in water purification. However,
such techniques are cumbersome and undesirable for the user. Thus,
it is desirable to provide an economical self-contained dispenser
shutoff and filter cartridge which may be easily replaced when a
monitor indicates that the filter has reached the end of its useful
life.
In general, prior art patents and known water dispensing disabling
devices (herein termed "shutoff devices") with a filter
have tended to concentrate on ways of interrupting water flow through
the bottle opening once the filter has reached the end of its useful
life, by physically blocking water flow. However, this may result
in an interruption in dispensing when the water container still
has a substantial volume of water in it, which is not desirable
from a user viewpoint. To overcome this problem, some prior art
devices provide specific shutoff mechanisms so that when the filter
cartridge is removed, dispensing is stopped; these devices also
require a separate filter monitor device to visually or audibly
warn the user that the filter has reached the end of its useful
life. Many such shutoff devices have also tended to have a number
of moving parts, increasing the risk of part malfunction.
However, there is a need for a water filter shutoff device which
monitors water usage and automatically disables dispensing when
the filter has reached the end of its useful life, without the need
to rely on visual or audible warning signals. Such a filter shutoff
device would also preferably meet the following constraints. Given
space constraints, the shutoff device preferably is integral with
the filter, and should not unduly impede flow through the filter.
The shutoff device would also preferably allow presetting at the
time of manufacture to change the allowable water flow or application
uses, so that the device could be used with differently rated filters
and differently sized water containers. The device should be economical
to manufacture and preferably not require an entirely new mold or
any substantial additional investment in assembly equipment or fixtures,
while also being relatively simple in design with few moving parts
to reduce quality control risks. The shutoff device would also preferably
disable dispensing, without interrupting water flow from the currently
used water container, when a monitor indicates the useful life of
the filter is over.
A filter shutoff device preferably meets NSF criteria, including
qualifying as a filter "performance indication device"
(PID) under NSF standards, and include component materials that
have existing NSF approval for extraction. If no filter monitor/PID
is provided for a water dispenser with a filter, obtaining NSF approval
currently requires that the filter be tested to work at 200% of
its rated capacity. If a PID is provided, the filter need only be
tested to work at 120% of its rated capacity for NSF approval. For
example, if a filter is rated for 150 gallons, and a filter PID
is provided, the filter need only have a capacity of 180 gallons,
as opposed to 300 gallons if no filter PID is provided. This is
a significant added cost feature for a filter manufacturer, since
providing a filter capable of filtering 300 gallons requires additional
media content resulting in a significant added cost.
Filter shutoff devices must also be provided with venting in some
manner to allow continuous water flow, without "lock up".
One problem with such devices is that, upon initial use, as water
from the inverted water bottle flows into the device, water pressure/water
hammer conditions may cause unfiltered water to leak or spurt out
of the venting channels and into the dispensing unit. A sufficient
volume of water may escape filtration in this manner, such that
the device may not receive NSF approval for, e.g., lead testing.
It is also desirable to provide a filter shutoff device which overcomes
this problem.
Accordingly, an object of the present invention is to provide a
shutoff device integral with a filter and useable with a water dispenser,
in which the water dispenser is automatically disabled at the end
of the useful life of the filter.
Another object of the invention is to provide a filter shutoff
device which does not impede or interrupt water flow between the
water dispensing device and a water source such as an inverted water
bottle. A further object is to provide such a device that qualifies
as filter PID under NSF standards, enabling the more economical
manufacture of the filter.
Yet another object is to provide a filter shutoff device which
may be manufactured in an economical manner, such that the device
monitors the number of water containers used, disables further dispensing
after a predetermined number of uses, and then may be discarded
and replaced with a new device.
A further object is to provide a filter shutoff device which automatically
disables the connection between the device and a water container,
rather than simply providing a visual indication of end of filter
life, and rather than maintaining the ability to make this connection
and physically impeding or interrupting water flow.
A still further object is to provide such a device with an appropriate
size and configuration, together with appropriately located and
sized vent holes, to ensure that unfiltered water does not leak
out of the device and be dispensed.
DEFINITION OF CLAIM TERMS
The following terms are used in the claims of the patent as filed
and are intended to have their broadest meaning consistent with
the requirements of law. Where alternative meanings are possible,
the broadest meaning is intended. All words used in the claims are
intended to be used in the normal, customary usage of grammar and
the English language.
"Automatic filter shutoff device" means a device in fluid
communication with a water container which filters water and then
interferes with the ability to dispense water from the container
after a predetermined amount of water usage (i.e., the "shutoff"
feature), which may generally correspond to the useable life of
the filter, has been reached. "Automatic" in this context
means that shutoff occurs without the need for user intervention,
such as without the need for the user to respond to a visual or
audible signal from a filter monitor.
"Monitoring and disabling mechanism" means a mechanism
which monitors filter life by monitoring water usage, and which
includes a shutoff feature.
SUMMARY OF THE INVENTION
The objects mentioned above, as well as other objects, are solved
by the present invention, which overcomes disadvantages of prior
filter shutoff devices for water dispensers, while providing new
advantages not believed associated with such devices.
In one preferred embodiment, An automatic filter shutoff device
is provided, and is removably connected to a water container and
in fluid communication with a water dispenser. The device is adapted
to monitor water dispensing and disable dispensing after a predetermined
amount of water usage. The device includes a housing containing
a water filter and removably connected to the water container; and
a monitoring and disabling mechanism having a shutoff apparatus
moveable between first and second locations, the first location
being one in which water dispensing is monitored by the mechanism,
and the second location being one in which the mechanism is placed
in an interfering position with the connection between the housing
and the water container. The shutoff apparatus automatically moves
into the second location after the predetermined amount of water
usage has occurred, and without interrupting water dispensing from
the then-connected water container, so that the used filter shutoff
device must be replaced in order to reestablish connection to a
successive water container. Preferably, the predetermined amount
of water usage generally corresponds to the useable life of the
filter.
In a preferred embodiment, the filter shutoff device is adjustable
so that dispensing may be disabled after differing amounts of water
usage. In one preferred embodiment, the shutoff apparatus includes
a plunger whose vertical height may be varied, and the second location
is one in which the plunger obstructs the connection of the filter
housing and the water container. The monitoring and disabling mechanism
may include a filter cap with a downwardly depending leg having
a locking window engageable with a locking tab located on the shutoff
apparatus. The engaging surfaces of the locking tab and locking
window may be angled to facilitate entry of the tab within the window,
and to prevent disengagement of the tab and window.
In a particularly preferred embodiment, the plunger has a top surface
with a throat opening and annular side walls with spaced openings,
and wherein the surface area of the orifice is approximately equal
to the surface area of the side openings.
The monitoring and disabling mechanism may include a filter cap
mounting radially disposed, opposing teeth, and the shutoff apparatus
may include a rotary indexer having a radially protruding tab iteratively
communicating with the teeth. In this embodiment, the rotary indexer
monitors water dispensing by tracking the number of water containers
used during dispensing. Preferably, the monitoring and disabling
mechanism is a NSF-compliant performance indication device.
A visual indicator, such as a color band located on an outer surface
of the filtering and disabling mechanism, may be provided to warn
the user that the filter is nearing the end of its useful life.
The monitoring and disabling mechanism may also include a visual
indication to facilitate adjusting of the mechanism for differing
water usages.
In an alternative embodiment, the monitoring and disabling mechanism
may include a helical-shaped spring, and a rotary index engageable
with teeth having a number corresponding to the predetermined amount
of water usage.
In another aspect of the invention, a filter mechanism is provided
which is connected to a bottled water container and adapted to be
inverted and placed in fluid communication with a water dispenser.
The filter mechanism includes a housing containing a water filter
with a throat removably connected to the bottled water container.
The throat is a restricted orifice sized, such as less than one
inch or about 3/4-inches in diameter, for example, to permit a volumetric
flow rate of not greater than about 7500 ml./min. of water passage
during inversion of the water container and initial flow from the
container into the filter. A plurality of vent holes located in
an upper surface of the filter housing are provided; the vent holes
are sized to permit air from the filter to escape into the water
container and allow continuous water flow from the container into
the filter. When a new water container is connected to the housing,
the water level within the filter does not reach the vent holes
in the filter housing. This embodiment may, but need not, including
a monitoring and disabling mechanism having a shutoff apparatus
as described above.
BRIEF DESCRIPTION OF THE DRAWINGS
The novel features which are characteristic of the invention are
set forth in the appended claims. The invention itself, however,
together with further objects and attendant advantages thereof,
will be best understood by reference to the following description
taken in connection with the accompanying drawings. The drawings
illustrate one preferred embodiment of the present invention. As
further explained below, it will be understood that other embodiments,
not shown in the drawings, also fall within the spirit and scope
of the invention.
FIG. 1 is a perspective view of a water bottle being filled, together
with one preferred embodiment of a filter shutoff device according
to the present invention;
FIG. 2 is a perspective view showing the threaded connection of
a preferred embodiment of the filter shutoff device according to
the present invention to a water bottle;
FIG. 3 is a perspective view showing the filter shutoff device,
now attached to the water bottle, just prior to seating onto the
upper housing of a water dispenser;
FIG. 4 is a perspective view showing various components of a preferred
filter shutoff device according to the present invention;
FIG. 5 is a perspective view of the preferred, assembled filter
shutoff device;
FIG. 6 is a top view of FIG. 5;
FIG. 7 is a sectional view along reference line 7--7 of FIG. 6;
FIG. 8 is a side and planar perspective view of a preferred form
of the plunger component of the filter shutoff device;
FIG. 9 is a side and planar perspective view of the plunger and
a partial cross-sectional view of the filter cap;
FIG. 10 is a side and planar partial, cross-sectional view of the
plunger and filter cap;
FIG. 11 is a side and planar partial, cross-sectional view of the
plunger, filter cap and filter housing;
FIG. 12 is a side and planar perspective view of the plunger, filter
cap, spring and filter housing;
FIG. 13 is a side and bottom perspective view of the lower portions
of the plunger and filter cap;
FIG. 14 is an exploded view of the area circled "14"
in FIG. 13;
FIG. 15 is a side cross-sectional view of the preferred assembled
filter shutoff device;
FIG. 16 is an exploded view of the locking mechanism of the preferred
filter shutoff device;
FIG. 17 is a side cross-sectional view of an alternative embodiment
of the filter shutoff device of the present invention;
FIGS. 18 and 19 are partial, side cross-sectional views showing
two positions of the locking mechanism of an alternative filter
shutoff embodiment;
FIG. 20 is a side and planar cross-sectional view of the alternative
filter shutoff embodiment of FIG. 17;
FIG. 21 is a side and planar perspective view of the monitoring
and shutoff components of the alternative filter shutoff device
of FIG. 17;
FIG. 22 is a side and planar perspective view of the assembled
components shown in FIG. 21;
FIGS. 23-25 are side, enlarged views of the FIG. 17 embodiment
showing opposed teeth and their interaction with a tab of the alternative
filter shutoff device;
FIG. 26 is a partial side and cross-sectional view of an alternative,
one-piece embodiment of the filter shutoff device of the present
invention;
FIG. 27 is a partial sectional view along reference line 27/27
of FIG. 26;
FIG. 28 is a sectional view along reference line 28/28 of FIG.
26; and
FIG. 29 is an exploded view of a portion of filter cap 80 of FIG.
10.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Set forth below is a description of what are currently believed
to be the preferred embodiments and/or best examples of the invention
claimed. Future and present alternatives and modifications to these
preferred embodiments are contemplated. Any alternatives or modifications
which make insubstantial changes in function, in purpose, in structure
or in result are intended to be covered by the claims of this patent.
Referring first to FIGS. 1-3 a water container such as water bottle
20 is shown, together with a preferred embodiment of the filter
shutoff device of the present invention, generally referred to as
30. While it is preferred that water bottle 20 have threads 35 that
allow threaded connection with mating threads 25 on the neck of
water bottle 20 a threaded connection is not required.
Referring to FIG. 3 filter shutoff device 30 is sized and shaped
to permit its placement within opening 27 of water cooler housing
26. (The particular water dispenser chosen for use is of little
importance to the present invention.) For this purpose, filter device
30 may include an enlarged rim or neck 37 that rests on the top
peripheral wall 27a of aperture 27.
Referring now to FIGS. 4-6 one preferred embodiment of filter
device 30 includes the following components: filter cap 80; plunger
90; spring 57; support or media retaining ring 33; and upper and
lower filter pads 32a, 32b. Upper pad 32a is preferably sonic-welded
to ring 33 inside rim 33a; lower pad 32b is preferably sonic-welded
to the lower interior of filter housing 36. Pads 32a, 32b maintain
the filter media, such as activated charcoal 64 in place within
filter housing 36. During assembly, plunger 90 is placed down through
within center opening 92a of plunger 90. Spring 57 compresses against
plunger 90 and, in turn, is compressed by retaining ring 33; compression
is maintained on plunger 90 for the reasons described below. Filter
cap 80 may be sonic-welded to the upper surface of filter housing
36 since, in the preferred embodiment, filter shutoff 30 is designed
to be replaced, rather than cleaned and re-used, when the useful
life of the filter is over. Filter housing 36 is preferably generally
cylindrical in shape, as shown, and includes passages 38 (FIG. 11)
in its lower surface which permit water passage through the lower
end of filter housing 36. Ribs 113 on the outer surface of housing
36 facilitate gripping of the housing by the user. Filter cap 80
includes vent holes 120 which, in the preferred embodiment shown,
are six in number.
Referring to FIG. 8 a preferred form of plunger 90 includes an
annular top surface 92 with a restricted throat opening 92a. Legs
93 project downwardly from top surface 92 and include projections
93b and retaining tabs 93a. Annular wall 91 and legs 93 are separated
by arcuate openings such as U-shaped openings, as shown.
Referring to FIGS. 7 and 10 filter cap 80 has an inner annular
wall 83 with internal threads 35. Annular wall 83 houses an opposing
series of angled teeth, lower teeth 81 and upper teeth 82. Prior
to installation of a water bottle, projection 93b of plunger 90
is in an upper position in between upper teeth 82. Upon installation
of water bottle 20 projection 93b will move straight down about
1/4 inch (equal to the distance that the lower edge of the water
bottle must travel to meet the filter cap threads 35) until projection
93b lies between two lower teeth 81. As the water bottle is threaded
onto the filter cap, projection 93b will continue to move downward
between the two lower teeth 81. Referring to FIG. 29 projection
93b preferably traverses the path shown by circuit 188.
Filter cap 80 and plunger 90 are preferably designed such that
projection 93b does not touch either the upper surface 82a of upper
teeth 82 or the lower surface 81b of lower teeth 81 (see FIG. 10),
so that projection 93b is not stressed during use. While other dimensions
may obviously be used, in a preferred embodiment upper teeth may
have a length equal to the length of projection 93b teeth 81. For
example, in the preferred embodiment, the shorter and longer sides
of upper teeth 82 may have a length of 0.062 and 0.109 inches, respectively,
while the shorter and longer sides of lower teeth 81 may have a
length of 0.253 and 0.294 inches, respectively. (The individual
teeth may vary slightly in length, given the individual sections
of the collapsible cored use to mold the filter cap.) By designing
the filter cap so that the lower teeth 81 are longer than the upper
teeth 82 this ensures that follower projection 93b will index over
and into position so that when threading the filter cap onto the
bottle, projection 93b will continue down the correct channel between
the lower teeth, and avoid backtracking of projection 93b due to
clockwise rotation of the threading action.
In operation, and referring now to FIGS. 7-16 plunger 90 rotates
as filter shutoff device 30 is replaced and connected to new water
bottles. Plunger rotation is caused by the interaction of projection
93b with opposing angled teeth 81 82. During normal water dispensing
and filter use, plunger 90 is positioned at a vertical level that
permits threaded connection of threads 35 of filter cap 80 with
threads 25 on the neck of bottle 20 (FIG. 2). Plunger 90 is maintained
by spring 57 in the highest vertical position permitted. As plunger
90 incrementally rotates during the successive use of water bottles,
projection 93b moves within opposing teeth 81 82 which are off-set
and angled to induce this rotation. (This continues until retaining
tab 93a reaches locking window 84. Upon locking, which is further
discussed below, plunger 90 is locked at a vertical level such that
the plunger covers threads 35 and interferes with engagement of
the threads by a water bottle.
Referring to FIGS. 13-16 "lead-in" angled surfaces 93a.sub.1
and 84a of retaining tab 93a and locking window 84 respectively,
are provided. These surfaces are angled to allow the locking tab
to cam its way onto the inside surfaces of window "frame"
84a as a result of the rotation of plunger 90 during the last few
iterative movements of projection 93b between teeth 81 82 just
prior to the locking of tab 93 within window 84. This camming action
flexes leg 93 toward the filter throat until retaining tab 93a clears
ramped surface 84a and enters the window itself.
The locking mechanism is also designed to reduce the risk of losing
the locking function, as now described. Referring to FIG. 16 if
the user tries to connect the bottle threads to filter shutoff device
30 after the locking mechanism has been engaged (and, thus, retaining
tab 93a lies within locking window 84), a downward force is exerted
on plunger 90 by the water bottle end. This pushes retaining tab
93a against the bottom surface 84b of locking window 84. Bottom
surface 84b and the adjacent bottom surface of locking tab 93a are
each angled slightly in a downward direction moving away from filter
throat 91a. This results in locking tab 93a having a tendency to
"bury" itself deeper into locking window 84 rather than
trying to slide back toward the filter throat and losing engagement
with the locking window.
Referring to FIGS. 9 and 11 opening 85 is provided as a relief,
to ensure that projections 93b on the plunger do not shear off as
the plunger is installed. In addition, opening 85 provides a visual
indication to the installer, giving the installer the ability to
choose the number of iterations necessary before lock-up of the
filter occurs. For example, in the device shown in FIG. 11 fifty
teeth 81 82 and three openings 85 are provided about the inner
circumference of cap 80. The positions of openings 85 allow a design
in which, by initially locating the plunger so that projection 93b
is situated in an opening 85 filter shutoff device 30 can be configured
to provide any number of iterations necessary to correlate the volume
of bottles being used and the filter rating, and trigger filter
lock-up.
The openings of plunger 90 should be appropriately sized, as now
described. First, plunger top 92 is preferably provided with a restricted
circular throat 92a, to reduce water hammer through the plunger.
In the preferred embodiment, this opening has a diameter of about
3/4 inches, which is 0.442 in.sup.2. Once the opening in plunger
top 92 is sized, the vertical slots in apron 91 of plunger 90 are
then sized, by providing slots having an area such that the effective
surface area of the openings permitting water travel out the side
annular walls of plunger 90 is equal to the surface area of throat
opening 92a in plunger top surface 92.
Given this preferred plunger size and configuration, it was found
that water will fill the upper chamber of the filter, i.e., above
media retaining ring 33 and below cap 80 relatively slowly, such
that water will not be permitted to pass through vent holes 120.
In a particularly preferred embodiment, an early warning signal
may be used to notify the user of the impending end of the filter's
useful life. For example, a red flag may be sprung into position
within the center of the filter when 90% of the filter's useful
life has expired. As another example, bi-colored icons or a graduated
bi-color band 191 (FIG. 12) may be used to indicate that the useful
life of the filter is nearing an end, by matching dot or projection
190 on rotating plunger top surface 92 for example, with band 191.
Filter cap 80 carrying opposed teeth 81 82 may be manufactured
by machining a collapsible core, such as those available from Detroit
Mold Engineering of Detroit, owned by Cincinnati Millicron (Catalog
No. CC-402-PC). When designing the teeth, a proper draft angle is
required to insure release from the molding surface. Each of the
teeth has a different shape depending on where they are located
on the collapsing core. The collapsing action of the DME core is
inward, or perpendicular to the primary draw angle of the mold,
and works with a specific number of pie shaped segments, as disclosed
in U.S. Pat. Nos. 3247548 and 3660001 incorporated herein by
reference. These pie shapes, usually consisting of twelve segments,
may have two different sizes, e.g., six large and six small. Each
segment should be machined separately.
Another aspect of the invention concerning vent holes 120 is now
discussed. Referring to FIG. 3 when water bottle 20 is inverted
into a dispensing position, a seal is created between shutoff filter
rim 37 and bottle seat ledge 27a. To allow continuous dispensing
without lock-up, air passes from outside the filter through vent
holes 120 in filter cap 80 (FIG. 6), and into water bottle 20. When
the filter is initially installed on the bottle and the bottle is
rotated into the functioning position, during the time that water
flows down and wets and fills the filter media, the water flow path
that presents the least amount of resistance, and thus the path
the water actually travels, is through the vent holes. This is believed
due to a water hammer effect such that the existing air already
in the filter will tend to escape through these vent holes, carrying
water with it. This initial condition may result in some (less than
about 1 cc.) untreated water escaping through the vent holes and
into the treated water. This initial condition may result in a failure
to comply with NSF regulations regarding lead treatment, for example.
To solve this problem, a reduced throat diameter "D"
(FIG. 6) is provided, e.g., the throat diameter was reduced from
about 2 inches to about 3/4 inches, for example. In the preferred
embodiment, six vent holes 120 are provided on the upper surface
of filter cap 80 and pass completely through the filter cap. One
preferred size of the vent holes is about 0.031 inches; however
the vent holes may be sized larger, in which case fewer than six
may be used. Vent holes 120 permit air to escape from the filter,
and flow between the bottle threads and into the water bottle. Using
this restricted throat diameter, when water bottle 20 is inverted,
water slowly passes into filter shutoff device 30 such that the
water level in the device slowly rises. In a particularly preferred
embodiment, 0.7266 minutes was required for 3500 ml. of water to
flow through a filter shutoff device having a throat diameter of
about 3/4 inches (a fill rate of 4817 ml./min), whereas only 0.1728
minutes was required for the same volume of water to flow through
an identical filter with a throat diameter of about 1.5 inches (a
fill rate of 20255 ml./min). It was noted that water hammer continued
to cause water passage through the vent holes until the fill rate
was reduced below about 7500 ml./min. Unlike prior art designs,
even during the filling stage and before the water reaches its final
level within the filter due to the pressure head created by the
bottle neck, the water level never reaches above the level of vent
holes 120. With this design, then, water never flows out through
the vent holes, allowing NSF compliance, and reducing spillage and
mess.
Referring now to FIGS. 17-25 an alternative embodiment of the
filter shutoff device of the present invention, generally referred
to as 130 is shown. Referring first to FIG. 17 filter cap 180
has opposed vertical walls 139 ending in tabs 139a designed to removably
snap into the opening formed by rim 141a of ring 141. The outside
walls 141b of ring 141 preferably taper, as shown, to make room
for this removable snap fit. A filter, not shown, is contained within
opening 152 created by this connection
Referring still to FIGS. 17-25 filter cap 180 is assembled to
a monitoring and locking device, generally referred to as 140 which
consists of rotary indexing ring 141 and stationary ring 143. Ring
141 includes a number of teeth 144a axially spaced about the upper
internal periphery of the ring, and a flexible or spring-loaded
tab 145 positioned along the outside edge of ring 141 having a
distal end 145a and a function described further below. Ring 143
includes a curved annular disc 144 with two curved springs 146
which may be helically-shaped, opposing tabs 148 on the ring periphery,
and two opposed indexing tabs 147. Indexing tabs 147 each have triangular
projections 147a, 147b, preferably shaped as shown.
Referring now to FIGS. 23-25 during normal water dispensing and
operation of the filter, teeth 144a are positioned as shown in FIG.
23. Each time filter shutoff device 130 is removed from an empty
water bottle 20 and threaded to a new water bottle, device 140 is
shaped, sized and configured to provide an rotary indexing movement
such that tab 147 is advanced in a counter-clockwise direction (as
seen when looking downward on device 130) the distance of one tooth,
as now explained. Each time device 130 is removed from an empty
water bottle, ring 143 is forced upward by springs 146 causing
two adjacent teeth 144a to be positioned adjacent triangular projection
147b, as shown in FIG. 24. The interaction of the leading tooth
144a.sub.1 against projection 147b causes an incremental counter-clockwise
rotation of ring 144 and indexing tab 147 (when viewing device 130
from a downward direction). Then, when a new water bottle is threadably
attached to device, 130 ring 143 is forced in a downward direction
by the neck of the bottle. When this occurs, indexing tab 147b moves
downward as well so that leading tooth 144a.sub.1 now contacts projection
147a, causing another incremental counter-clockwise rotation of
ring 144 and indexing tab 147 as shown in FIG. 25 such that trailing
tooth 144a.sub.2 is in the position that leading tooth 144a.sub.1
of FIG. 23 previously occupied.
In this manner, ring 143 is continued to be advanced in a rotary
direction until the disassembly of device 130 from an empty water
bottle causes spring-loaded tab 145 to reach opening 150 in vertical
wall 139 of filter cap 180. Now, distal edge 145a, which was earlier
prevented from doing so (see FIG. 18), enters opening 150 and halts
further rotary movement of ring 143 and indexing tab 147 as shown
in FIGS. 19-20. When this occurs, device 130 can no longer be threadably
connected to a new water bottle since the presence of distal end
145a within opening 150 prevents downward movement of ring 143
so that ring 143 remains in a position that covers internal threads
135 of filter cap 180 as shown in FIG. 20.
As will now be understood, the components of filter monitoring
and locking device 140 may be shaped and oriented such that the
number of teeth used corresponds to the number of bottles which
may be used before the filter is disabled. For example, if 45 teeth
are used for 3-gallon bottles, then the filter disable device will
activate after 135 gallons of water have been used.
In an alternative preferred embodiment, shown in FIGS. 26-28 filter
monitoring and locking device 240 is of one-piece construction,
and includes a single molded component consisting of upper ring
243 and lower ring 241. Indexing tab 247 extends down from ring
244 and includes an upper opening 247c with a pointed tab 245. Indexing
tab 247 also includes a lower, stepped series of openings 247d.
In a similar manner as described above, ring 243 and tab 247 are
rotary indexed in a counter-clockwise direction (again, when viewing
device 240 from above) by the stepped orientation and interaction
of openings 247d with teeth 244a, as shown in FIGS. 26 and 28. As
the filter shutoff device is used, removed and then connected to
a new water container, tab 247 rotates and pointed tab 245 moves
within succeeding angled openings 260. When tab 247 reaches a position
permitting the entry of tab 245 into opening 270 on ring 241 (FIG.
27), further rotary movement of ring 243 ceases, disabling the filter
shutoff device by preventing its threaded connection with water
container 20.
It will be understood that the filter shutoff device of the present
invention may be used with water containers other than the inverted
water bottles shown in the drawings. For example, the device may
be used with water pitchers or sports bottles. It will also be understood
that the filter shutoff device may be used with a variety of water
dispensing devices, and a variety of filters, other than those specifically
described here.
While the invention has been described with reference to a threaded
connection between filter shutoff device 30 and water bottle 20
it will be understood that device 30 may be modified for use with
water containers that are not intended to be threadably connected
to device 30. For example, filter shutoff device 30 could be used
with non-threaded connections between device 30 and water bottle
20 such as those described in U.S. Pat. Nos. 5222531 and 5289855
incorporated herein by reference, such that a cap could be press-fit
onto the filter device. As another example, instead of both the
water container and the filter shutoff device having threads, one
could have a partial thread and the other a simple projection that
would engage the partial thread when the filter shutoff device is
rotated; this could act as a helical ramp for the projection, pulling
the two components tightly together.
The above description is not intended to limit the meaning of the
words used in the following claims that define the invention. Rather,
it is contemplated that future modifications in structure, function
or result will exist that are not substantial changes and that all
such insubstantial changes are intended to be covered by the claims. |