Note: Descriptions are shown in the official language in which they were submitted.
1 3383:51
IMPROVED BOTTLED WATER COOLER
APPARATUS AND METHOD
This is a divisional of Canadian patent application serial
No, 611,291 filed on September 13, 1989.
Background of the Invention
This invention concerns bottled water dispensing
systems in general and also bottled water dispensing systems
equipped to supply carbonated water derived from a bottled
water source.
Bottled water dispensers of the type which are in
common current use in the United States employ an inverted
bottle, the neck of which extends into a reservoir which is
housed in the body of the dispenser. The reservoir may or may
not be provided with means for chilling the water. This
arrangement is inherently unsanitary due to contact between
the exterior neck and top of the bottle and the water in the
reservoir. The bottled water consumer is advised to clean the
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top of the bottle before inverting it, but this is
rarely done to a sufficient extent.
Furthermore, the principle of operation of
inverted-bottle-type dispensers requires that air
enter the space between the mouth of the inverted
bottle and the top of the water level in the
reservoir. Airborne microbes and small particular
matter can enter the drinking water system each time
the bottle demands air and "glugs". This has
prompted devices which filter or limit the pathway
of the air entering the system.
Current dispenser systems typically do not
provide the kind of seal necessary to eliminate
contamination of the system from spillage of liquid
on top of the bottle. Such liquid can come from a
variety of sources including overwatering of plants
placed on top of the inverted bottle. The liquid
can then run down the sidewalls of the bottle and
into the system. Similarly, certain animals, such
as parrots, have been known to light on top of the
bottle and contaminate convention systems by
urinating on top of the bottle.
Conventional bottled water dispensing systems
also have two additional drawbacks: first, they
require that the consumer or installer lift and
invert a heavy bottle; second, conventional systems
often require more space than that which is
available in today's kitchen.
Carbonated beverage dispensing systems need to
dispense carbonated liquid at very close to freezing
temperatures in order to retain high levels of
carbonation in the dispensed liquid. In this
regard, carbonated beverage dispensing systems using
bottled water sources have presented special
engineering challènges because of the desirability
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of using the thermal storage characteristics of ice
banks while still maintaining compact size and
existing electromechanical packaging. Carbonated
beverage dispensing systems which use bottled water
sources have also employed refrigeration controls
which can be both ambient temperature and altitude
sensitive. These sensitivities can cause
differences in the amount or even presence of ice in
the unit which can directly affect drink dispensing
temperature, carbonation level and drink making
capacity. The adjustment required to compensate for
different altitude and ambient temperature
environments constitutes a further drawback to the
use of conventional bottled water temperature
controls. Although convention controls may be
adjustable, such a system introduces and interface
between user or installer which requires judgement
or training and constitutes a sales negative.
Furthermore, some known carbonator
configurations include carbonator vessels wrapped
with refrigeration coils. It is often desirable to
operate the evaporator at a subfreezing temperature
in such systems. Naturally this makes such a system
prone to freezing of the fluid in the carbonator.
Further, level sensors having moving parts to
control supply pumps can present operating problems.
It may be necessary to adjust evaporator temperature
used in production of such systems slightly higher
in order to avoid the possibility of icing up the
carbonator. This translates to a dispensing
temperature which is marginally higher with
concomitant reduction in carbonation level during
dlspenslng.
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Summary of Invention
In accordance with one embodiment of the
present invention, an improved carbonator level is
provided which has no moving parts, and which can be
easily serviced. The carbonator system and method
may be operated remotely by electrical components
coupled to fluid lines that are connected to the
carbonator. In this manner, the liquid level in the
carbonator is remotely controlled in response to the
volumetric absorption of carbon dioxide in water as
a function predominantly of the temperature of the
water supplied to the carbonator. Two embodiments
of the present carbonator method systems are adapted
for operation as a stand-alone unit or as a sub-
system in a home refrigerator.
Various aspects of the invention are as
follows:
A carbonation system comprising:
a carbonator operatively coupled to receive a
source of liquid to be carbonated and a source of
carbon dioxide under pressure;
means for chilling the liquid to be carbonated
supplied to the carbonator;
means for chilling the liquid to be carbonated
supplied to the carbonator;
means for dispensing the carbonated liquid from
the carbonator;
first means for sensing the presence of
adequate liquid to be carbonated operatively coupled
to said source of liquid to e carbonated;
second means for sensing the presence of carbon
dioxide gas;
pressure sensing means coupled to said
carbonator;
and
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control means responsive to said first and
second means and to said pressure sensing means to
initiate the flow of liquid to be carbonated into
said carbonator during dispensing and to inhibit the
flow of liquid to be carbonated into said carbonator
in response either to said first or second means
sensing the insufficient supplies of liquid to be
carbonated or carbon dioxide or to the pressure
sensing means sensing pressure exceeding a
predetermined level.
A method of carbonating a liquid within a
vessel, the method comprising the steps of:
supplying chilled water to be carbonated to the
vessel;
supplying carbon dioxide gas to the vessel;
sensing the volumetric absorption efficiency of
carbonation within the vessel for controlling the
supply of liquid to be carbonated to the vessel.
Description of the Drawinqs
Figure 1 shows the arrangement of Figures lA
and lB which, in combination, form a pictorial
diagram of an embodiment of the carbonator according
to the present invention;
Figure 2 shows the arrangement of Figures 2A
and 2B which, in combination, form a pictorial
diagram of the carbonator according to another
embodiment of the present invention for operation in
convention refrigerator;
Figure 3 is an exploded view of the ice
crystallizer according to one embodiment of the
present invention;
Figure 4 is a partial sectional view of an ice
crystallizer according to another embodiment of the
present invention, and
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Figure 5 is a sectional view of a stirring
mechanism according to the present invention.
Figure 6 is an exploded partial cutaway view of
the carbonator according to one embodiment of the
present invention; and
Figure 7 is another exploded partial cutaway
view of the carbonator according to another
embodiment of the present invention.
Description of the Preferred Embodiment
Referring now to Figure 1, there is shown a
pictorial diagram of a bottled water dispensing
system including provision for dispensing carbonated
water. Hot water dispensing apparatus is not shown
but may be added using conventional means. An
upright bottle of water 2 is equipped with an air
tight cap 4. This cap may be the original cap
provided on the sealed bottle of water which is
subsequently pierced or, alternatively, a permanent
but removable cap which is user serviceable. Air
tight seals 6 are provided in cap 4 to permit fluid
to be propelled out of the bottle of water via
conduit 8 by air supplied via conduit 10 from air
pump 12. Since the air supplied may be ambient, it
first is filtered by filter 14 of known construction
to remove both particulate and microbial matter
prior to introduction into contact with the drinking
water system. Filter 14 may also be used as deemed
desirable to absorb other airborne contaminants.
Drinking water 16 is propelled via conduit 8
from bottle 2 into reservoir 18. Conduit 8 may be
provided with a check valve 20 to prevent water from
draining back to bottle 2 when cap 4 is removed for
servicing.
Reservoir 18 is equipped with a vent valve 24
which effectively seals reservoir 18 when the liquid
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level therein rises above a predetermined level. In
one embodiment, vent valve 24 may be floating ball
which seals against a seat when the liquid level 22
rises above a predetermined level. Vent valve 24 is
coupled to vent port 26 which provides a gas pathway
from the inside to the outside of reservoir 18. In
order to protect the system against entering
airborne contamination, the vent port 26 is provided
with filter cap 28. Cap 28 may be equipped with
filtration capability ranging from a simple cover to
the full contaminant filtration of the type
previously described for filter 14. Air pump 12 may
be provided with relief means 13 which limits
pressure and cools the pump 12, if necessary. With
the advent of low cost, low noise, continuous duty
air pumps, air pump 12 may operate substantially
continuously.
The pressure in bottle 2 needed to propel the
water or other liquid therefrom may also be supplied
from a regulated supply of gas under pressure, such
as a cylinder of gas of nitrogen, air, or other
propellant. In such an embodiment it is desirable
to inhibit gas flow when the water bottle 2 iS empty
or near empty. This can be accomplished with level
controls appropriately placed in water bottle 2 or
reservoir 18 and a solenoid valve disposed
downstream from the aforementioned gas cylinder.
Reservoir 18 is equipped with a dispensing
valve 30 depending from the bottom thereof which
allows liquid to be removed from reservoir 18.
Generally, this configuration is useful when the
flow rate of liquid desired through valve 30 is
greater than the flow rate of liquid entering
reservoir 18 from water bottle 2 via conduit 8,
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i.e., the capacity of air pump of gas source 12 is
not sufficient to keep up with the dispensing rate.
In another embodiment of the present invention
in which liquid flow into reservoir 18 is
sufficient, it can be desirable to operate the
system without vent valve 24, vent port 26 and
filter cap 28, thus creating a substantially closed
reservoir 18. Dispensing valve 30 may then be
located near the upper portion of reservoir 18 for
dispensing water from this location. In this
embodiment, it is desirable to include a drain port
located at the lowest point in reservoir 18 in order
to permit easy sanitizing and full drain capability.
It should be recognized that the sanitary
system of Figure 1 may be operated successfully in a
more convention manner. Thus reservoir 18 may be
opened, vent components 24, 26 and 28 eliminated and
bottle 2 inverted into reservoir 10. In this
configuration, the air pump 12 and other components
associated with propelling the liquid to reservoir
18 may also be eliminated.
Referring now to the refrigeration system of
Figure 1, there is shown compressor 32, the high
temperature side of which is connected to condenser
34. Continuing in the direction of refrigerant
flow, condenser 34 is coupled to filter-drier 36,
the cross section of which necks down 38 into
capillary tube 40. The capillary section ends at
the transition 42 to evaporator 44. Evaporator 44
is wrapped around carbonator vessel 46. The
refrigeration system may further be equipped with an
evaporator pressure regulator (EPR) 48 which is used
to control the evaporator temperature/pressure in
the segment of evaporator 44 between transition 42
and EPR 48. Continuing further in the direction of
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refrigerant flow, evaporator 44 continues through a
low pressure section 50 which is then coiled around
reservoir 18 in close thermal contact therewith.
The refrigeration loop is completed with connection
of the evaporator 44 to the suction port 52 of
compressor 32.
In actual practice, EPR 48 is set to maintain
operating refrigerant temperatures/pressures
slightly below zero degrees Celsius in the portion
of evaporator 44 between transition 42 and EPR 48.
The section 50 of evaporator 44 is generally
insulated over its length before coiling around
reservoir 18, which may be spaced some distance from
vessel 46. The pressure drop across EPR 48 usually
allows the pressure downstream from EPR 48 to
operate at a lower pressure and lower temperature in
that portion of evaporator 44, which is wrapped
around reservoir 18.
Temperature control within reservoir 18 is
attained through use of a temperature or ice bank
control 54 having a sensing element 56 disposed in a
thermal well 58. Thermal well 58 is in intimate
contact with the liquid within reservoir 18. This
temperature control makes the use of a liquid-filled
ice-bank control that is convenient and effective,
particularly when thermal well 58 is placed at a
location near the maximum desired limit of ice
build-up from the walls of reservoir 18.
In a preferred embodiment of the present
invention, reservoir 18 is equipped with means to
circulate the liquid contained therein. Thus
reservoir 18 iS provided with stirring motor 60
coupled to drive impeller 62 as later described in
detail herein. Reservoir 18 is also coupled to a
water level sensor. In a preferred embodiment, as
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shown in Figure 1, a conduit 66 connects reservoir
18 to pressure switch 64. Pressure switch 64 is
shown in its operating position when reservoir 18 is
nearly full, i.e., above its upper trip limit. In
this position, electric current is continuously
available to ice bank control 54.
When the level in reservoir 18 falls below a
predetermined level, which is generally at or near
the level of the ice bank sensor 56, switch 64
switches to its normal unpressurized state. Thus,
electrical current to both the compressor 32 and to
the stirring motor 60 is terminated.
In certain applications, however, it may not be
desirable to stop the compressor 32 when the liquid
level falls in reservoir 18 because, for example,
warming liquid in reservoir 18 may present
sanitation problems, thus making it more
advantageous to keep the liquid in reservoir 18 cold
at all times, regardless of the liquid level
thereof. On the other hand, it is not acceptable to
run the compressor 32 continuously without the
control function of ice bank sensor 54. In one
embodiment of the present invention, line voltage L1
is supplied directly to ice bank controller 54
without being series-wired through pressure switch
64, as shown and a thermal bridge or pathway is
provided between the thermal well 58 and the
evaporator coils wrapped around reservoir 18. Such
a bridge thermally couples the coils to the ice bank
sensor 56 to indicate "freeze" condition, even
though liquid may not be present in the immediate
vicinity thereof.
Alternatively, reservoir 18 can be equipped
with a low-cost temperature controller 72 which
receives its supply voltage directly but
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independently from pressure switch 64. Switch or
controller 72 may be placed in close thermal contact
with the sidewalls or evaporator coils of reservoir
18, and may be set to make contact closure (or
conduct) on temperature rises above a predetermined
level. Switch 72 may be designed to conduct at 5
degrees Celsius, for example.
In operation, switch 72 will cycle compressor
32 regardless of the water level in reservoir 18 and
independently of ice bank controller 54 wired as
shown. A properly placed and calibrated switch can
keep any amount of water chilled in reservoir 18 as
a backup to ice bank controller 54.
It should be recognized that other arrangements
may be used to control the temperature or volume of
ice in reservoir 18. For example, a standard
bottles water cooler temperature control with
modified temperature set points or temperature
differentials may be used. In such an embodiment,
the temperature sensing element is generally placed
in a well disposed on the exterior of the reservoir
18 in close thermal contact with the evaporator
coils wrapped around the reservoir 18.
The principle of operation of such a control is
that as ice builds inside the reservoir 18, the
thermal load on the system is reduced and the
evaporating temperature falls rather rapidly as the
ice bank builds. The sensor, in close thermal
communication with such an evaporator, activates a
controller which turns off the compressor 32. While
this configuration offers some advantages,
especially in terms of cost, it should be recognized
that most of the inexpensive controls on the market
today use refrigerant-filled sensing elements and
differential pressure switches in the controller.
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This arrangement makes the set points of the control
change as a function of altitude. Furthermore, this
type of control does not have a sensing element in
direct contact with the ice in the reservoir 18. As
a result, there is a tendency for the length of the
refrigeration cycle to change rather markedly with
ambient temperature and this, in turn, can produce
profound changes on the size and shape of the ice
bank produced. The degree of the ambient
temperature effect depends to an extent on the
effectiveness of the thermal insulation used.
Alternatively, sensing of evaporator
temperature can be useful if an absolute pressure
switch is used and the entire unit 15 is protected
against wide fluctuations in temperature. Thus if
temperature control 72 is not altitude sensitive and
operates on electronic principles, for example, this
represents a substantial improvement. A further
advantage of this type of controller is that the
need for controller or switch 72 can be eliminated
in configurations where positive cooling of water is
required, regardless of level. Other schemes for
regulating the volume of ice in the ice bank may
also be used, including by sensing the change in
electrical conductivity with the change in state
from water to ice. While these sensors are more
costly than the aforementioned liquid-filled ice
bank controls, their very positive action and
accuracy can provide control advantages.
Reservoir 18 is further provided with a baffle
68 and an ice crystallizer 70. The purpose of the
baffle is to quiet the fluid entering reservoir 18
through conduit 8. Thus, conveying warm water
directly to the outlets of reservoir 18 is avoided.
The purpose of ice crystallizer 70 is to provide
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initial crystallization of ice on the first cycling
of the refrigeration system.
Generally, the reservoir 18 is formed of
plastic or stainless steel. With the reservoir 18
is formed of plastic or stainless steel. With the
reservoir 18 wrapped with refrigeration coils, the
inside surface of reservoir 18 is relatively uniform
in temperature and such uniformity is enhanced by
the liquid circulation created by stirring motor 60
and impeller 62.
On initial start up of the system, cold bands
created by localized coils on the outside of
reservoir 18 will be distributed so that the
localized cold "seen" on the interior of reservoir
18 does not reflect true evaporator temperature.
Stated in another way, the circulating water in
reservoir 18 is of relatively uniform temperature.
As heat from the liquid moves through the walls of
reservoir 18 and is absorbed by the evaporator
coils, the wall of reservoir 18 serves to distribute
the heat.
It has been found in such systems, especially
those equipped with stirring means, that initial
freezing takes place when the liquid temperature is
significantly below 0 degrees Celsius. It is
believed that the phenomenon as it applies to the
present invention has two components. The first can
be ascribed to the known phenomenon of the need to
nucleate an ice crystal. Thus, a body of pure water
may not freeze even when held at below its freezing
point until an ice crystal nucleates someplace in
the body which then causes rapid further
crystallization. In the absence of such nucleation,
it is known that vibrations, scratching and
supercooling will bring about initial and rapid
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crystallization of a super cooled body of water.
Second, the circulation resulting from rotating
impeller 62 may further impede crystallization. It
is believed that the continuous sweeping of the
interior sidewalls of reservoir 18 results in more
temperature uniformity and therefore more difficulty
in maintaining or producing localized supercooled
cold spots. The actively moving water may thus
impede the initial crystallization.
In one embodiment of the present invention, it
has been observed that initial crystallization will
take place at about -4 degrees Celsius. A
conventional liquid-filled ice bank sensor 26, as
discussed above, includes water inside a bulb. Some
manufacturers also place seeding compounds such as
Aquamarine Beryl Ore therein to aid initial
crystallization of the water to ice. This causes
the change of state to occur nearer 0 degrees
Celsius. One commercial component, the Ranco C-12-
1800 control, for example, will freeze (i.e.,
operate to deactivate compressor 32) at about -3.3
degrees Celsius. If ice has not formed in reservoir
18 by this time, the compressor will cut out and
subsequent refrigeration cycles may not initiate the
formation of ice with the result that a dispenser
thus configured will have very limited drink making
capacity. Although the user might "adjust" the
operation if the drink-making capacity is noticeably
limited, this involves a user or installer function
which is not desirable.
There is a further difficulty with systems
operating with water which is allowed to drop
significantly in temperature below 0 degrees Celsius
before being brought into the freezing state. It
has been observed that the amount of "slush" created
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in a crystallizing body of water is related the
temperature at which crystallization is first
initiated. For example, if circulating at -1 degree
Celsius is seeded with a crystal of ice, generally a
large number of very small crystals will develop
over a period of about 15 seconds. The temperature
of the liquid will rise to about -.2 degrees Celsius
over the crystallization period. Such
crystallization normally does not pose a problem for
system operation. By contrast, if circulating water
at -5 degrees Celsius is seeded, crystallization
results in the entire mass of fluid in the reservoir
turning to slush over a similar period of time.
Considering the energy relationship and the
heat of fusion Ho of water, the temperature as
measured in the center of reservoir 18 in the
present example rapidly rises from -5 degrees
Celsius prior to crystallization to very near 0
degrees Celsius afterward. It does not quite reach
this level instantly because the ice, i.e., the
solid part of the slush, is below 0 degrees Celsius
initially. It has been observed on initial
operation of the present invention that the rate of
temperature drop of the fluid in reservoir 18 is
slower after 0 degrees Celsius temperature is
reached. This is of significance since the liquid
in reservoir 18 may remain fully liquid at
subfreezing temperatures for a significant period of
time. If the carbonation pump 74 is operating at a
time when the temperature in reservoir 18 causes
serious slushing, the ice can enter the inlet of the
pump. In actual practice it has been observed,
especially with vibrating oscillating pumps, that
the initiation of the pumping cycle has brought
about crystallization and slushing. The slush can
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then enter the pump and, in some instances, the
discharge line 76 thereof. Such components are
prone to clogging. Carbonator 46 is equipped with
an internal nozzle of small size which can also clog
on small ice particles in the slush. Any clogging
thus produced inhibits the carbonation pump 74 from
properly moving water into the carbonator 46. In
accordance with the present invention, ice
crystallization is initiated at a higher
temperature, thus avoiding the possibility of large
amounts of obstructing slush entering the
carbonation system.
The ice crystallizer 70 includes a rotating
vane which is disposed to scratch or otherwise
impinge upon the interior walls of reservoir 18.
Alternatively, a crystallizer which restricts the
circulation of water in a location near an
evaporator cold band may also be used, as later
described herein.
Referring now to the carbonation system of
Figure 1, there is shown carbonator pump 74
operatively coupled to reservoir 18 by conduit 76.
The discharge line of pump 74 is coupled to
carbonator 46, which preferably has no internal
moving parts. Generally, the carbonation pump 74
incorporates one or more check valves therein to
prevent backflow of fluid from carbonator 46 into
reservoir 18.
Also coupled to carbonator 74 is a source of
carbon dioxide gas 80 under pressure which is
preferably equipped with valve means 82 to close off
the supply of gas. The gas source 80 is generally
at high pressure which must be regulated to about 55
psi by the regulator 84 that is connected in conduit
86, which is operatively coupled to carbonator 46.
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In order to prevent backflow of gas or liquid from
carbonator 46, a check valve 88 is provided in conduit
86. In a preferred embodiment, male/female quick connect
coupling set 90 can be interposed between regulator 84
and valve means 82. Manual relief valve 92 is also
connected to conduit 86 to relieve pressure from the gas
lines prior to opening the manual quick connect coupling
set 90. Coupling set 90 is preferably constructed to
provide a pressure interlock which does not permit the
coupling to be disengaged when the system is pressurized.
Thus, the sequence for the changing of the carbon
dioxide cylinder 80 is as follows: close valve 82; open
relief valve 92 and allow system gas to vent; disengage
quick connect coupling set; install new gas source.
Coupled to the low pressure gas system is pressure
sensor 94 which operates to transfer contacts from the
position shown when the pressure sensed is below a
predetermined minimum level. Alternate means may also be
used for sensing the presence of adequate carbon dioxide
for beverage carbonation. Such alternate means include,
for example, devices which sense the weight of the
cylinder of carbon dioxide 80 and provide contact
transfer when the weight of the cylinder falls below a
predetermined minimum level.
Also coupled to carbonator 46 is a dispensing valve
96 and a relief valve 104. The relief valve 104 may be
equipped with an orifice to vent the carbonator in
response to dispensing, or it may be a relief valve to
prevent over pressure conditions in the carbonator.
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Further, a pressure switch 98 is connected to
carbonator 46 via dispensing line 102 to detect
dispensing and to initiate the operation of
carbonation pump 74. A flow restrictor 100 may be
included in the dispensing line 102 in order to make
certain that the signal received by pressure switch
98 is sufficient to overcome switch hysteresis and
delay time associated with contact transfer.
Dispensing line 102 may, in addition, take the form
of an appropriately sized choke line, as known in
the art.
Referring to pressure switches 64 and 94, two
pilot lights 106 and 108 are connected to the
normally closed (when no pressure is present)
contacts of those switches to illuminate when the
water bottle and carbon dioxide supplies need
replacement.
It can be shown that both replace carbon
dioxide indicator lamp 108 and "Replace Water
Bottle" indicator lamp 106 cannot both be
illuminated at the same time. That is, if the
"Replace Water Bottle" lamp 106 is on, the supply
voltage to "Replace Carbon Dioxide" indicator lamp
108 is inhibited. If desired, this arrangement can
be modified by means which will be obvious to those
skilled in the art. It should also be recognized
that the pressure switches and other components can
be operated at less than main voltage and provide
functional equivalent control.
Pressure switch 64 is also coupled to a drain
line 110 which is an extension of conduit 66. Drain
line 110 is further provided with a drain valve 112
which may take the form of a small plastic pinch
valve which snaps over flexible plastic tubing to
make a seal. The drain line 110 and drain valve 112
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provide a means for flushing and sanitizing the internal
components of pressure switch 64 and for purging air from
the ports and diaphragm area of pressure switch 64.
Although no moving parts are required in the
carbonator just described, it is possible to substitute
therefor a more conventional carbonator incIuding a level
sensor disposed in the carbonator tank for mechanically
or electromechanically controlling the amount of water in
the tank 46.
The operation of the carbonation system of the
present invention depends for proper operation upon the
phenomenon observed, as known, pertaining to the
volumetric absorption of carbon dioxide gas in a
carbonator being dependent upon the temperature of the
water in the carbonator. For a carbonator with rapid
liquid throughput, this may effectively translate to the
temperature of the incoming liquid.
While there are other complicating factors such as
the presence of atmospheric gases, and carbonator
efficiency it can be said for many practical
applications, including the bottled water application of
the present invention, that the volumetric absorption of
gas in the carbonator is predominantly determined by
temperature of the liquid. This is the case, however,
only when the pressure generated and held by air pump 12
is slightly over 1 atmosphere absolute and the desired
lift is small. Ordinarily, this will be on the order of
a few feet. In this manner, the maximum dissolved air in
the water in bottle 2 and reservoir 18 is kept only
slightly above equilibrium with 1 atmosphere absolute.
The maximum air pressure in
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1 338351
the head space above the liquid in the carbonator
will also be near 1 atmosphere absolute.
In operation, when a new bottle 2 of water 16
is put into place and electricity is supplied to the
system, pump 12 begins to pressurize the air space
above water 16 in bottle 2. Water is displaced
through conduit 8 and check valve 20 into reservoir
18. As filling of reservoir 18 proceeds, the water
level surpasses the contact transfer point set on
pressure switch 64 causing "Replace Water Bottle"
indicator lamp 106 to extinguish. The same contact
transfer supplies current to stirring motor 60 and
to compressor 32 through ice bank control 54.
Operation of stirring motor 60 causes the water and
ice crystallizer 70 to rotate.
Operation of compressor 32 causes refrigerant
to flow through condenser 34, filter drier 36,
capillary tube 40, evaporator 44, ERP 48, then back
to the compressor 32 via suction port 52.
The water in reservoir 18 is thereby chilled.
As the temperature approaches 0 degrees Celsius, the
crystallizer 70 precipitates ice at a water
temperature slightly above or below this
temperature.
An ice bank subsequently begins to form and
continues to grow inside reservoir 18 until it
extends to a point near ice bank sensor 56. As the
ice bank extends to the thermal well in which the
sensor 56 is housed, the liquid in the sensor will
freeze and deliver a pressure pulse to ice bank
controller 54 which turns off the compressor 32.
Thereafter, the refrigeration system will cycle
periodically as heat enters the system and dissolves
a portion of the ice bank to expose the thermal well
58 in the vicinity of ice bank sensor 56.
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Cold water near 0 degrees Celsius may now be
dispensed from dispense valve 30, or be drawn off by
carbonator pump 74 and supplied to the carbonator
46. As water is dispensed from reservoir 18 and
tepid water enters from water bottle 2, it is
rapidly chilled by the action of the circulating
water against the ice bank. When carbonated water
is dispensed through valve 96, the pressure on
pressure switch 98 falls rapidly due to the pressure
drop across flow restrictor 100. In one embodiment
when the pressure drops below 45 psi, the contact on
switch 98 falls to its normally closed
(unpressurized) position. If there is sufficient
carbon dioxide and sufficient water in reservoir 18,
as evidenced by the positions of pressure switches
94 and 64 respectively, carbonation pump 74 will be
turned on. The carbonation pump 74 draws near-
freezing water from reservoir 18 and delivers it to
the inlet nozzle of carbonator 46 to fill the
vessel.
During the dispensing of carbonated water from
dispense valve 96, carbon dioxide gas flows from
source 80, through quick-connect coupling set 90,
regulator 84, conduit 86, and check valve 88 to
displace at least a portion of the liquid volume
dispensed. Gas continues to flow into carbonator 96
until the regulator set point is reached at about 55
psi .
When dispensing is complete, carbonation pump
46 continues to operate because the flowrate
therethrough is less than the flowrate at which the
carbonated water was dispensed. As the carbonator
46 fills with near-freezing water, some carbon
dioxide gas may continue to flow from source 80 into
carbonator 46, as demanded, to maintain the 55 psi
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set point in the carbonator. As the carbonator
continues to fill, the liquid level in carbonator 46
reaches a level where the efficiency of carbonation
begins to fall. (It has been found that in
carbonators of approximately 4 inches in diameter
and 9 inches in height, the efficiency of
carbonation drops quickly as the distance between
the liquid level and the nozzle (which is disposed
near the top of carbonator 46) decreases to less
than two inches.) The drop in the efficiency of
carbonation is manifested as a reduction in the gas
flowrate into carbonator 46 during filling (without
dispensing). As the liquid level rises, the flow of
gas from source 80 stops completely (indicating the
condition of unitary volumetric absorption),
followed by a rise in pressure as the liquid level
in carbonator 46 nears the level of the inlet nozzle
at the top of the vessel. When the pressure in
carbonator 46 reaches approximately 60 psi, switch
98 resets to its original position shown in Figure
1, thus turning off carbonation pump 74. Filling of
the carbonator 46 is complete and a full charge of
carbonated water is ready to dispense.
The present invention thus uses upon the
physical properties of the fluid in the carbonator
46 to generate a pressure signal which can be sensed
through the fluid lines connected to the carbonator.
It is for this reason that carbonator 46 can be
operated without conventional internal level
controls, and without the use of electrical lines to
the carbonator.
It can be shown that the present system will
not allow large quantities of warm water to enter
the carbonator 46. As an example, water entering
the carbonator at 20 degrees Celsius during system
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start up (i.e., before the refrigeration system has
had an opportunity to cool reservoir 18) exhibits
maximum volumetric absorption of pure carbon dioxide
at 55 psi of about .86 volumes of gas for each
volume of water. In practice, however, the amount
of gas actually absorbed decreases because the
carbonation process is less than 100 percent
efficient, and decreases further when atmospheric
gasses are present. Thus, typical volumetric
absorption in the above example is about .7 volumes,
or less.
In practice this phenomenon leads to a rapid
increase in carbonator pressure before the
carbonator is full. Thus, pressure switch 98
deactivates the carbonator pump 74 in a short time
after the carbonator begins to fill. It is,
therefore, common with this type of system for the
carbonator to fill only slightly on start up. This
has the advantage, especially for operation of the
system as a home dispenser, that dispensing of a
large quantity of warm carbonated water is inhibited
by the system of the present invention.
One important feature of the present invention
is the ability to 'tune' the system to specific
carbonator operating conditions. Since carbonator
efficiency, the level of atmospheric gasses, and
temperature all affect volumetric absorption within
the carbonator, these factors may be used to control
such absorption. Further, if two of the variable
conditions can be held constant, the volumetric
absorption can be controlled by the remaining
variable condition. In one embodiment of the
present invention, the practical significance of
this is that volumetric absorption controls the
liquid level in the carbonator. Also, the
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1 338351
temperature of the system of the present invention,
both in the carbonator and in the inlet liquid, is
controlled. Further, many sources of bottled water
are aerated during processing or are obtained from
aerated sources and are delivered in a relatively
well aerated state.
If air is used to pressurize water bottle 2,
the water therein and reservoir 18 will tend to
aerate and come to equilibrium over time. The
remaining variable, (i.e., the efficiency of
carbonation, may be controlled by various means
including input flowrate, pressure drop across the
inlet nozzle, and carbonator design parameters such
as surface area of liquid, orientation of the inlet
nozzle, and the like.
It can be shown that a system which is
efficiency tuned, for example, to provide a
volumetric absorption slightly over 1.0 volume of
gas per volume of liquid when operated at 0 degrees
Celsius and 1 atmosphere of dissolved air, becomes
quite sensitive to temperature variation. That is,
volumetric absorption falls below 1.0 quickly when
the operating temperature of such a system rises
above 0 degrees, in substantial correlation with the
solubility curve of carbon dioxide in water. These
physical properties are used in the carbonated-water
dispensing system of the present invention to
inhibit the dispensing of large volumes of
carbonated water when the system is operating at
temperatures above predetermined design levels.
Referring now to Figure 2, there is shown an
alternate embodiment of the present invention
adaptable for use in a home refrigerator. The
functional components of the system that are the
same as in Figure 1 bear similar legends.
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1 338351
Bottle 2 iS generally placed in a convenient
location outside the refrigerator such as under the
sink or in the garage. Bottle 2 is operatively
coupled to a level sensor 202 and a level controller
204. The function of the sensor and controller 202,
204 is to inhibit the flow of electricity at least
to pump 74 when the water level in the bottle 2
drops below a predetermined level. Conventional
level sensing, for example, including sensing the
weight of bottle 2, electrical conductivity sensing,
optical means, pressure sensing means, and float
switch means may be used.
It is desirable in the upright bottle
configuration shown to empty almost completely the
bottle of water 2 before the sensor 202 delivers its
signal to controller 204 to turn off the pump
circuit. It is therefore desirable that the sensing
means be repeatably sensitive and reliable when the
water level in bottle 2 is very low. Sensors, for
example, using electrical conductivity principles or
optical sensing can provide advantages in this
regard. It should be noted, however, that the
electrical conductivity sensors if used need to be
sufficiently sensitive to effectively trigger when
distilled or purified water in supplied. Optical
sensors of known construction employ the difference
in the index of refraction of air and water to
detect the presence of water in the bottle 2. Thus
probe 202 may be lowered almost to the bottom of
bottle 2.
The system of Figure 2 is further provided with
a chiller reservoir 206 which is placed within the
chilled environment, for example, of a refrigerator.
It is desirable for reservoir 206 to incorporate
structures which induce 'plug' flow of water and may
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1 33835 1
also incorporate therein means for rapidly passing
air bubbles therethough, as known in the art.
Instead of the two faucet dispensing system of
Figure 1, there is shown in Figure 2 a single
dispense valve 208 which has a three way valve 210
disposed upstream therefrom. By adjusting valve 210
as desired, either chilled or carbonated water may
be dispensed through valve 208.
When water is demanded, either by dispensing
carbonated or chilled water, water from bottle 2 is
propelled by air pump 12 through chiller reservoir
206. In addition to the controls indicated in
Figure 1, a pressure switch 212 may be operatively
coupled to the system pressurized by air pump 12.
This switch may be connected to inhibit the flow of
electricity to air pump 12 when the system pressure
exceeds a predetermined minimum level. Thus, air
pump 12 may be operated on demand.
The carbonation system is driven by a
carbonation pump 74 whose inlet is connected to
receive the water from bottle 2. Figure 2, the
carbonation pump 74 has an inlet which is downstream
from chiller reservoir 206. Such a configuration
can be convenient in original equipment applications
where subjecting chiller reservoir to high pressures
may not represent optimum safety design
configuration relative to possible system leaks.
Such original-equipment configurations may also
include control valves to inhibit the flow of water
- 30 from bottle 2 to the interior of the refrigerator
cabinet under certain conditions such as in the
absence of dispensing or under 'vacation' or 'off'
control settings.
It should also be noted that carbonation pump
74 may be interposed in conduit 8 so that the inlet
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1 338351
of pump 74 is in direct contact with the water 16 in
bottle 2. In this configuration it is necessary to
provide conventional means connected to prevent
backflow into the fresh water inlet supply from
carbonator 46. Further, air pump 12 and optional
associated control 212 may be eliminated from the
illustrated embodiment of Figure 2 if pump 74 serves
both as a dispensing pump and as a carbonation pump
with the capability of handling both chilled water
and carbonator flow rate demands. However, since
high flow, high pressure pumps of the type required
to create good beverage carbonation are generally
expensive, the embodiment using a single pump, as
described above, may not be the low-cost embodiment,
even though components such as air pump 12 and
pressure switch 212 may be eliminated.
In the embodiment of Figure 2, a flow
restrictor 100, as in Figure 1, is eliminated
(although conduit 102 may still be as a choke line),
and flow restrictor 214 is included in the carbon
dioxide supply line leading to carbonator 46 to
provide a slight pressure drop when fluid is
dispensed form the carbonator, which pressure drop
can be sensed by pressure switch 98 operatively
coupled to the carbonator.
Pressure switch 98 may also be connected in the
discharge side of pump 74 or in discharge line 78.
It is generally necessary in such an embodiment to
adjust the control pressure level or hysterses
operating conditions of the switch 98.
In the embodiment of Figure 2 in a home
refrigerator application, it is possible to locate
all of the electrical components remote from the
carbonator 46 which is best disposed within the
refrigerator for retrofit applications.
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1 338351
Referring now to Figure 3, there is shown one
version of a crystallizer which may be used in the
embodiment of the present invention illustrated in
Figure 1. There is shown a baffle 68 having a hole
in the center through which the spindle 300 is
positioned. Spindle 300 is equipped with a grooved
portion 302, a threaded portion 304 and a slotted
area 306. The shank portion 308 of spindle 300 fits
through an oversize hole 310 in rotary vane 312.
The tip to tip dimension of rotary vane 312 is
slightly less than the internal diameter of
reservoir 18. Assembly of spindle 300 to rotary
vane 312 is completed with washer 314 and is secured
with snap ring 316. The threaded portion 304 of
spindle 300 protrudes above the snap ring 316
sufficiently to be secured to baffle 68 through hole
318 with knurled nut 320.
In operation, the liquid movement within the
reservoir 18 produced by rotating impeller 62 causes
rotary vane 312 on the underside of baffle 68 to
rotate inside reservoir 18. The oversize hole 310
allows rotary vane 312 some freedom of movement
about its rotational axis which, given the
dimensions of the vane 312, allows the vane tips 322
to impinge on the interior sidewalls of reservoir
18. When the fluid in reservoir 18 is near or below
freezing, repeated impingement from the vane tips
322 cause crystallization of the water in reservoir
18.
Referring now to Figure 4, there is shown an
alternate means of initiating crystallization.
Reservoir 18 is wrapped with refrigeration
evaporator coils 330 in close thermal communication
with the sidewalls of the reservoir 18. A small
tube 332 is housed within a larger tube 334, both of
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which are affixed to the interior sidewall of
reservoir 18. The function of the tube within a
tube design is to provide a sheltered environment or
quiescent conditions in the chilled water in the
interior portion of the inner tube 332 is that
cooled by the close proximity of evaporator coils
330 to promote nucleation or initial
crystallization. In a top-feed evaporator system,
it is found that the coldest point in the system is
near the capillary tube inlet, and the crystallizer
of Figure 4 is located near this point on the side
wall of reservoir 18 for enhanced operation. The
effectiveness of a crystallizer may be determined by
the water temperature in reservoir 18 at which the
first crystals of ice are formed.
Referring now to Figure 5, there is shown an
embodiment of the stirring mechanism in the
illustrated embodiment of Figure 1. Stirring motor
62 is disposed below the level of the bottom 350 of
reservoir 18. In this position, the same stirring
mechanism may be used when the top of reservoir 18
is open to receive an inverted bottle of water, or
is configured for operation with an upright bottle,
as illustrated in Figure 1. Motor 60 is coupled to
drive shaft 352 at the end of which a magnetic bar
354 is affixed. Motor 60 may be mounted to
reservoir support pan 356 as shown which is
separated from the bottom 350 of reservoir 18 by
styrofoam insulating material 358.
Reservoir bottom 350 is outfitted with a
stationary seal and bearing 360. The bearing
orifice 372 of the seal bearing 360 is provided to
aid centering of magnetic impeller 62. The seal
against reservoir bottom 350 is formed with o-ring
364 compressed by the tightening of nut 362.
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The stirring mechanism is also provided with a
shroud 366 having an inlet orifice 368 and an outlet
orifice 370. The inlet orifice is disposed in the
top of the shroud 366 and the outlet orifice is
disposed in the side of the shroud.
This arrangement effectively creates a small
pump in reservoir 18, the outlet of which can be
directed circumferentially to produce a steady
rotating mass of liquid in reservoir 18.
In operation, motor 60 drives magnetic bar 354
which is magnetically coupled through the bottom of
reservoir 18 to the magnetic impeller 62, and the
two magnets rotate in concert with one another, thus
providing a pumping action within shroud 366 that
circulates the water in reservoir 18.
Referring now to Figure 6, there is shown an
exploded partially cutaway view of the carbonator of
the present invention. Carbonator 46 includes an
outer shell 362 which forms one part of a pressure
vessel. Shell 362 may be formed of stainless steel
and may be deep drawn or welded into the shape
shown. Further, it is possible to mold the shell
362 from thermoplastic material such as
polycarbonate. The lower end 364 of shell 362 may
be hemispherical or otherwise rounded to increase
the pressure holding capability thereof.
Shell 362 is equipped with an indented bead
portion or groove 366 which is used to retain plug
368, as described below, and which may be roll
formed or molded into place.
Carbonator plug 368 is dimensioned to fit into
shell 362 to a point determined by lip 370 of shell
362. This lip may be machined or molded into place
in shell 362. Alternatively, lip 370 may take the
form of a ridge or protrusion at the point indicated
1 338351
which limits insertion of plug 364 beyond the point
indicated.
Prior to fitting plug 368 into place, an o-ring
seal (not shown) is placed in o-ring groove 374
which effectively retains the o-ring when the plug
368 is assembled within the shell 362. When the
seal is lubricated and plug 368 is pressed into
place in shell 362, a gas and liquid tight seal is
formed between the plug 368 and the shell 362.
Final assembly is completed by fitting plastic or
metal ring 376 into place within groove 366 above
the top of plug 368. Ring 376 may be provided with
a slight outward spring bias so that it expands and
snaps into place in groove 366.
Carbonator 46 is also provided with a baffle
378 that is retained by retaining rings 380 and 382
on the outlet tube 384. It is convenient that
baffle 378 be positioned to segregate a "quiet"
volume of water below the baffle from the volume of
water above the baffle that is agitated by incoming
water as known in the art.
Outlet tube 384 is inserted directly into a
port (not shown on Figure 6) disposed on the
underside of plug 368 and in fluid communication
with outlet port 386 of carbonator plug 374. In a
similar manner, liquid inlet nozzle 388 is connected
in direct fluid communication with liquid inlet port
390 and is equipped with a nozzle 391 to direct a
stream of incoming liquid substantially downwardly.
Gas inlet port 392 is in direct fluid communication
with the interior of the carbonator 46. In the
embodiment illustrated in Figure 6, the carbon
dioxide enters at a level above the level of the
liquid in the carbonator 46. A tube may be
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1 338351
inserted, if desired to direct gas flow below the
operating levels of liquid within the carbonator.
Plug 368 is also provided in the embodiment
shown with a relief valve 394 and relief valve port
396. Plug 368 may further be provided with a
solenoid vent valve 398 and with a vent valve port
400.
One feature of carbonator 46 and plug 368 is
that the fittings which conduct fluids in and out of
the carbonator may be molded into place by
conventional injection molding processes to
facilitate quick-connect assemblage of the
components. Thus, ports 396 and 400 may include
standard female threads, and ports 386, 390, and 392
and their underside counterparts (not shown) may be
of the conventional push-in, quick-connect type.
Such fittings and components are commercially
available, for example, from John Guest U.S.A. and
have features that allow extremely easy insertion
and release. Incorporation of these fittings as an
integral component of plug 368 involves a sonic
welding of a cap (not shown) into place to complete
the assembly of plug 368. The nozzle 388 and outlet
tube may therefore be easily serviced or replaced as
necessary. Similarly, the tubing which connects to
ports 386, 390, and 392 may be simply inserted or
removed for assembly or servicing.
Referring now to Figure 7, there is shown an
inverted form of carbonator 46, the plug 368 of
which is identical to that in Figure 6. Some of the
push-in, quick-connect ports have been exchanged in
the inverted model, however, to accommodate the new
internal components. These components include vent
tubes 410 and 412 to provide gas communication from
the gas space shown above the operational liquid
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1 338351
level to solenoid valve 398 and vent valve 394,
respectively. Baffle 408 is modified to provide
additional orifices for tubes or conduits
therethrough, and nozzle 414, which directs the
incoming stream of liquid substantially downwardly,
is disposed in the gas space above the operating
liquid levels within the carbonator. Other nozzle
arrangements are, of course possible. In another
embodiment, the liquid stream can be directed
against impact plates, or spayed, etc. Carbon
dioxide inlet tube 416 directs the incoming carbon
dioxide gas just above baffle 408 which is suspended
above the underside of plug 368 by a retaining ring
418 on conduit or tube 416. A second retaining ring
(not shown) may be placed on top of carbon dioxide
inlet tube 416 to retain the baffle 408 in place.
X~
