Note: Descriptions are shown in the official language in which they were submitted.
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RAPID COMESTIBLE FLUID DISPENSING APPARATUS AND METHOD
Field of the Invention
This invention relates generally to fluid dispensers and more particularly, to
comestible fluids dispensers and to cooling, sterilizing, measurement, and
pressure control
devices therefor.
Background of the Invention
Despite significant advancements in fluid dispensing devices and systems, many
problems that have existed for decades related to such devices and systems
remain unsolved.
These problems exist in many different fluid dispensing applications, but have
a particularly
significant impact upon fluid dispensing devices and systems in the food and
beverage
industry as will be described below. Comestible fluid dispensers in this
industry can be
found for dispensing a wide variety of carbonated and non-carbonated pre-mixed
and post-
mixed drinks, including for example beer, soda, water, coffee, tea, and the
like. Fluid
dispensers in this industry are also commonly used for dispensing non-drink
fluids such as
condiments, food ingredients, etc. The term "comestible fluid" as used herein
and in the
appended claims refers to any type of food or drink intended to be consumed
and which is
found in a flowable form.
A majority of the long-standing problems in the comestible fluid dispensing
art are
found in dispensing applications for carbonated beverages. First, because the
fluid being
poured is carbonated and is therefore sensitive to pressure drops,
conventional carbonated
comestible fluid dispensers are generally slow, requiring several seconds to
fill even an
average size cup or glass. Second, when flow speeds are increased, the
dispensed beverage
often has an undesirably large foam head (which can overflow, spill, or
otherwise create a
mess) and is often flat due to the fast dispense. Some existing devices use
hydrostatic
pressure to push comestible fluid out of a holding tank located above the
dispensing nozzle.
One such device is disclosed in United States Patent Number 5,603,363 issued
to Nelson.
Unfortunately, these devices do not provide for pressure control at the
nozzle, and (at least
partly for this reason) are limited in their ability to prevent foaming and
loss of carbonation in
the case of carbonated comestible fluids. The working potential of rack
pressure in such
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devices is largely wasted in favor of hydrostatic pressure. By not maintaining
rack pressure
to the nozzles in these devices, carbonated comestible fluid inevitably loses
its carbonation
over time while waiting for subsequent dispenses. Also, like other existing
beer dispensers,
such devices cool and/or keep the comestible fluid cool by the relatively
inefficient practice
of cooling a reservoir or supply of comestible fluid.
Another problem of conventional comestible fluid beverage dispensers is
related to
the temperature at which the fluid is kept prior to dispense and at which the
fluid is served.
Some beverages are typically served cold but without ice, and therefore must
be cooled or
refrigerated prior to dispense. This requirement presents significant design
limitations upon
dispensers for dispensing such beverages. By way of example only, beer is
usually served
cold and must therefore be refrigerated or cooled prior to dispense.
Conventional practice is
to cool the beer in a refrigerated and insulated storage area. The process of
refrigerating a
beer storage area sometimes for an indefinite period of time prior to beer
dispense is fairly
inefficient and expensive. Such refrigeration also does not provide for quick
temperature
control or temperature change of the comestible fluid to be dispensed.
Specifically, because
the comestible fluid in storage is typically found in relatively large
quantities, quick
temperature change and adjustment by a user is not possible. Also,
conventional refrigeration
systems are not well suited for responsive control of comestible fluid
temperature by
automatic or manual control of the refrigeration system.
Unlike numerous other comestible fluids which do not necessarily need to be
cooled
(e.g., soft drinks, tea, lemonade, etc., which can be mixed with ice in a
vessel after dispense)
or at least do not require a cooling device or system for fluid lines running
between a
refrigerated fluid source and a nozzle, tap, or dispensing gun, beer is
ideally kept cool up to
the point of dispense. Therefore, many conventional dispensers are not
suitable for
dispensing beer. For example, beer located within fluid lines between a
refrigerated fluid
source and a nozzle, tap, or dispensing gun can become warm between dispenses.
Warm beer
in such fluid lines must be served warm, be mixed with cold beer following the
warm beer in
the fluid lines, or be flushed and discarded. These options are unacceptable
as they call either
for product waste or for serving product in a state that is less than
desirable. In addition,
because many comestible fluids are relatively quickly perishable, holding such
fluids
uncooled (such as in fluid lines running from a refrigerated fluid source to a
nozzle, tap, or
dispensing gun) for a length of time can cause the fluid to spoil, even
fouling part or all of the
dispensing system and requiring system flushing and cleaning.
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Because many comestible fluids should be kept cool up to the point of
dispense, the
apparatus or elements necessary to achieve such cooling have significantly
restricted
conventional dispenser designs. Therefore, dispensers for highly perishable
fluids such as
beer are therefore typically non-movable taps connected via insulated or
refrigerated lines to
a refrigerated fluid source, while dispensers for less perishable fluids (and
especially those
that can be cooled by ice after dispense) can be hand-held and movable,
connected to a
source of refrigerated or non-refrigerated fluid by an unrefrigerated and
uninsulated fluid line
if desired.
A comestible fluid dispenser design issue related to the above problems is the
ability
to clean and sterilize the dispenser as needed. Like the problems described
above, improperly
cleaned dispenser systems can affect comestible fluid taste and smell and can
even cause
fresh comestible fluid to turn bad. Many potential dispenser system designs
cannot be used
due to the inability to properly clean and sterilize one or more internal
areas of the dispenser
system. Particularly where dispenser system designs call for the use of small
components or
for components having internal areas that are small, difficult to access, or
cannot readily be
cleaned by flushing, the advantages such designs could offer are compromised
by cleaning
issues.
The problems described above all have a significant impact upon dispensed
comestible fluid quality and taste, but also have an impact upon an important
issue in most
dispenser applications: speed. Whether due to the inability to use well known
devices for
increasing fluid flow, due to the fact that carbonated fluids demand
particular care in their
manner of dispense, or due to dispenser design restrictions resulting from
perishable fluids,
conventional comestible fluid dispensers are invariably slow and inefficient.
In light of the problems and limitations of the prior art described above, a
need exists
for a comestible fluid dispensing apparatus and method capable of rapidly
dispensing
comestible fluid in a controlled manner without foaming or de-carbonating the
fluid even
between extended periods between dispenses, which is capable of maintaining
the comestible
fluid throughout the dispensing apparatus cool indefinitely and with high
efficiency, which
permits quick and accurate temperature control of comestible fluid dispensed
by automatic or
manual refrigeration system control, which can be in the form of a mounted or
hand-held
apparatus, which can be easily cleaned and sterilized even though relatively
small and
difficult to access internal areas exist in the apparatus, and which is
capable of monitoring
apparatus operation and dispense parameters for controlling dispense pressure,
flow speed,
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and head size. Each preferred embodiment of the present invention achieves one
or more of
these results.
Summary of the Invention
The present invention addresses the problems of the prior art described above
by
providing a nozzle assembly capable of controlling pressure of comestible
fluid exiting the
nozzle assembly, a refrigeration system that employs refrigerant pressure
control in the
refrigeration system to provide efficient and superior control of comestible
fluid temperature,
heat exchangers of a type and connected in a manner to cool comestible fluid
up to the exit
ports of dispensing nozzles, a sterilization system for effectively
sterilizing even hard to
access locations outside and inside the comestible fluid dispensing system,
and a hand held
comestible fluid dispenser capable of cooling and selectively dispensing one
of several warm
comestible fluids supplied thereto.
The present invention solves the problem of how to employ comestible fluid
rack
pressure as a pressure for the entire dispensing system without the associated
dispense
problems such relatively high pressure can produce (particularly in carbonated
beverage
systems such as beer dispensing systems, where it is most desirable to keep
carbonated fluid
pressurized for an indefinite period of time between dispenses). In one
embodiment of the
present invention, nozzle assemblies from which comestible fluid is dispensed
are provided
with valves each having an open position and a range of closed positions
corresponding to
different comestible fluid pressures at the dispensing outlet of the nozzle.
Control of the
valve to enlarge a fluid holding chamber or reservoir in the nozzle assembly
prior to opening
results in a lower controllable dispense pressure. Preferably, the valve is a
plunger valve in
telescoping relationship with a housing of the nozzle. Alternative embodiments
of the
present invention employ other pressure reduction elements and devices to
control dispense
pressure at the nozzle. For example, a purge line can extend from the nozzle
assembly or
from the fluid line supplying comestible fluid to the nozzle assembly. By
bleeding an
amount of comestible fluid from the nozzle or from the fluid line prior to
opening the nozzle,
a system controller can reduce comestible fluid pressure in the nozzle to a
desired and
controllable dispense level. Other embodiments of the present invention
control comestible
fluid pressure at the nozzle by employing movable fluid line walls, deformable
fluid
chamber walls, etc. Flow information can be measured and monitored by the
control system
via the same pressure sensors and/or flowmeters used to control nozzle valve
actuation,
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thereby permitting a user to monitor comestible fluid dispense and waste, if
desired.
To improve temperature control and cooling efficiency of the dispensing
system, the
present invention preferably employs heat exchangers adjacent to the nozzle
assemblies,
with no substantial structural elements to block flow between each heat
exchanger and its
respective nozzle assembly. Highly efficient plate-type heat exchangers are
preferably used
for their relatively high efficiency and small size. A venting system or plug
can be used to
vent or fill any head space that may exist in the heat exchangers, thereby
avoiding cleaning
and pressurized dispensing problems. Due to their locations close to the
nozzle assemblies,
the heat exchangers generate convective recirculation through the nozzle
assemblies to send
cold comestible fluid to the terminal portion of the nozzle assembly and to
receive warmer
comestible fluid therefrom. Comestible fluid therefore remains cool up to the
dispensing
outlet of each nozzle assembly. Also, because the comestible fluid is cooled
near the point
of dispense, the inefficient practice of refrigerating the source of the
comestible fluid for a
potentially long time between dispenses by convective cooling in an insulated
storage area
can be eliminated in many applications.
The present invention can take the form of a dispensing gun if desired,
thereby
providing for dispensing nozzle mobility and dispense speed. Preferred
embodiments of the
dispensing gun have a heat exchanger located adjacent to a nozzle assembly to
generate
cooling convective recirculation in the nozzle assembly as discussed above. To
increase
portability and a user's ability to manipulate the dispensing gun, the heat
exchanger is a
highly efficient heat exchanger such as a plate-type heat exchanger. The
dispensing gun can
have multiple comestible fluid input lines, thereby permitting a user to
selectively dispense
any of the multiple comestible fluids. Preferably, a valve is located between
the heat
exchanger and the nozzle assembly of the dispensing gun and can be controlled
by a user via
controls on the dispensing gun to dispense any of the fluids supplied thereto.
Like the nozzle
assemblies and heat exchangers mentioned above, the location of a heat
exchanger near the
point of dispense removes the requirement of refrigerating the comestible
fluid supply in
many applications. Also, pressure control at the nozzle is preferably provided
by a nozzle
assembly valve having a range of closed positions as mentioned above.
To further improve control of comestible fluid temperature, the present
invention
preferably has a refrigeration system that is controllable by controlling
refrigerant
temperature and/or pressure. Specifically, an evaporator pressure regulator
can be used to
control refrigerant pressure upstream of the compressor in the refrigeration
system, thereby
controlling the cooling ability of refrigerant in the heat exchanger and
controlling the
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temperature of the refrigerant passing through the heat exchanger. In addition
or
alternatively, a hot gas bypass valve can bleed hot refrigerant from the
compressor for
reintroduction into cold refrigerant upstream of the heat exchanger, thereby
also controlling
the cooling ability of refrigerant in the heat exchanger and controlling the
temperature of
comestible fluid passing through the heat exchanger, particularly in the event
of a low or
zero-load operational condition in the refrigeration system (e.g., between
infrequent
dispenses when fluid in the heat exchanger is already cold).
Preferred embodiments of the present invention have an ultraviolet light
assembly for
sterilizing external and internal surfaces of the system. The ultraviolet
light assembly has an
ultraviolet light generator and has one or more ultraviolet light transmitters
for transmitting
the ultraviolet light to various locations in and on the dispensing system.
For example,
ultraviolet light can be transmitted to the nozzle exterior surfaces
frequently immersed in
sub-surface filling operations, head spaces in the heat exchangers, and even
to locations
within fluid lines of the dispensing system. The ultraviolet light
transmitters can be fiber
optic lines, light pipes, or other conventional (and preferably flexible)
members capable of
transmitting the ultraviolet light a distance from the ultraviolet light
generator to the
locations to be sterilized.
Further objects and advantages of the present invention, together with the
organization
and manner of operation thereof, will become apparent from the following
detailed description
of the invention when taken in conjunction with the accompanying drawings,
wherein like
elements have like numerals throughout the drawings.
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Brief Description of the Drawings
The present invention is further described with reference to the accompanying
drawings,
which show a preferred embodiment of the present invention. However, it should
be noted that
the invention as disclosed in the accompanying drawings is illustrated by way
of example only.
The various elements and combinations of elements described below and
illustrated in the
drawings can be arranged and organized differently to result in embodiments
which are still
within the spirit and scope of the present invention.
In the drawings, wherein like reference numerals indicate like parts:
FIG. 1 is a perspective view of a vending cart having a set of rack nozzle
assemblies, a
dispensing gun, and associated elements according to a first preferred
embodiment of the
present invention;
FIG. 2 is an elevational cross section view in of the vending cart shown in
FIG. 1,
showing connections and elements located within the vending cart;
FIG. 3 is a comestible fluid schematic according to a preferred embodiment of
the
present invention;
FIG. 4 is an elevational cross section view of a rack nozzle assembly shown in
FIGS. 1
and 2;
FIG. 5 is a refrigeration schematic according to a preferred embodiment of the
present
invention;
FIG. 6 is a perspective view, partially broken away, of the rack heat
exchanger used in
the vending stand shown in FIGS. 1 and 2;
FIG. 6a is an elevational cross section view of the rack heat exchanger shown
in FIG. 6;
FIG. 7 is a side elevational cross section view of the dispensing gun shown in
FIG. 1;
FIG. 8 is front elevational cross section view of the dispensing gun shown in
FIG. 7,
taken along lines 8-8 of FIG. 7; and
FIG. 9 is a schematic view of a sterilizing system according to a preferred
embodiment
of the present invention.
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Detailed Description of the Preferred Embodiments
The present invention finds application in virtually any environment in which
comestible
fluid is dispensed. By way of example only, the figures of the present
application illustrate the
present invention employed in a mobile vending stand (indicated generally at
10). With
reference first to FIG. 1, the vending stand 10 is preferably a self-contained
unit, and can be
powered by a generator or by a power source via an electrical cord (not
shown). The vending
stand shown has a dispensing rack 12 from which extend a number of dispensing
nozzles 14 for
dispense of different comestible fluids. Also, the illustrated vending stand
10 has a comestible
fluid dispensing gun 16 capable of selectively dispensing one of multiple
comestible fluids
supplied thereto by fluid hoses 18. For user control of stand and dispensing
operations, the
vending stand 10 preferably has controls 20 (most preferably in the form of a
control panel as
shown) in a user-accessible location.
As shown in FIG. 2, the vending stand 10 houses a supply of beers preferably
in the
form of kegs 22. The following description is with reference to only one keg
22 and associated
pressurizing and fluid delivery elements (such as fluid lines, pressure
regulators, nozzles, and
other dispensing equipment), but applies to the other kegs 22 and their
associated dispensing
equipment that are not visible in the view of FIG. 2. Also, the following
description of the
invention is presented only by way of example with reference to different
embodiments of an
apparatus for dispensing beer. It should be noted, however, that the present
invention is not
defined by the type of comestible fluid being dispensed or the vessel in which
such fluid is
stored or dispensed from. The present invention can be used to dispense
virtually any other type
of comestible fluid as noted in the Background of the Invention above. Other
comestible fluids
often not found in kegs, but are commonly transported and stored in many other
types of fluid
vessels. The present invention is equally applicable and encompasses
dispensing operations of
such other comestible fluids in different fluid vessels.
As is well known to those skilled in the art, beer is stored pressurized, and
is dispensed
from conventional kegs by a pressure source or fluid pressurizing device such
as a tank of
carbon dioxide or beer gas (a mixture of carbon dioxide and nitrogen gas)
coupled to the keg.
The pressure source or fluid pressurizing device exerts pressure upon the beer
in the keg to push
the beer out of the keg via a beer tap. It should be noted that throughout the
specification and
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claims herein, when one element is said to be "coupled" to another, this does
not necessarily
mean that one element is fastened, secured, or otherwise attached to another
element. Instead,
the term "coupled" means that one element is either connected directly or
indirectly to another
element or is in mechanical or electrical communication with another element.
To regulate the
pressure of beer in the keg and the pressure of beer in the system, a pressure
regulator is coupled
to the pressure source in a conventional manner and preferably measures the
pressure levels
within the pressure source and the keg, and also preferably permits a user to
change the pressure
released to the keg. One comestible fluid pressurizer in the preferred
embodiment of the present
invention shown in FIG. 2 is a tank of carbon dioxide 24 coupled in a
conventional manner to
the keg 22 via a pressure line 26. A conventional pressure regulator 28 is
attached to the tank 24
for measuring tank and keg pressure as described above. A fluid delivery line
30 is coupled to
the keg 22 via a tap 32 also in a conventional manner and runs to downstream
dispensing
equipment as will be discussed below.
The tank 24, pressure line 26, regulator 28, keg 22, tap 32, delivery line 30,
their
operation, and connection devices for connecting these elements (not shown)
are well known to
those skilled in the art and are not therefore described in greater detail
herein. However, it
should be noted that alternative embodiments of the present invention can
employ conventional
fluid storage arrangements and comestible fluid pressurizing devices that are
significantly
different than the keg and tank arrangement disclosed herein while still
falling within the scope
of the present invention. For example, although not preferred in beer
dispensing devices, certain
comestible fluid storage devices rely upon the hydrostatic pressure of fluid
to provide sufficient
fluid pressure for downstream dispensing equipment. In such cases, the
comestible fluid need
not be pressurized at all, and can be located at a higher elevation than the
downstream
dispensing equipment to establish the needed dispensing pressure. As another
example, other
systems employ fluid pumps to pressurize the fluid being dispensed. Depending
at least in part
upon the storage pressure of the fluid to be dispensed, the fluid storage
devices can be in the
form of kegs, tanks, bags, and the like. Each such alternative fluid
pressurizing arrangement
and storage device functions like the illustrated embodiment to supply fluid
under pressure from
a storage vessel to downstream dispensing equipment (and may or may not have a
conventional
device for adjusting the pressure exerted to move the fluid from the storage
device). These
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alternative pressurizing arrangements and storage devices are well known to
those skilled in the
art and fall within the spirit and scope of the present invention.
With continued reference to FIG. 2, the delivery line 30 runs from the keg 22
to a rack
heat exchanger 34. The rack heat exchanger 34 is preferably a plate-type heat
exchanger
supplied with refrigerant as will be described in more detail below. The rack
heat exchanger 34
is preferably located in a housing 36 defining a rear portion of the
dispensing rack 12, and is
mounted therein in a conventional manner. The rack heat exchanger 34 has
conventional ports
and fittings for connecting beer input and output lines from each of the kegs
22 in the vending
stand 10 and for connecting input and output refrigerant lines to the rack
heat exchanger 34.
Extending from the rack heat exchanger 34 is a series of beer output lines 38
(one
corresponding to each keg 22), only one of which is visible in FIG. 2. Each
output line 38 runs
to a nozzle assembly 40 that is operable by a user to open and close for
dispensing beer as will
be described in more detail below.
In the preferred embodiment of the present invention illustrated in FIGS. 1
and 2, a beer
dispensing gun 16 is shown also connected to the kegs 22. Normally, either a
dispensing gun 16
or a nozzle assembly 40 (not both) would be supplied with beer from a keg 22.
Although both
could be connected to the same keg 22 via the tap 32 as shown in FIG. 2, such
an arrangement is
presented for purposes of illustration and simplicity only. The dispensing gun
16 is supplied
with beer from the kegs 22 by fluid lines 42, only one of which is visible in
FIG. 2. More
specifically, the dispensing gun 16 preferably has a plate-type heat exchanger
44 to which the
fluid lines 42 run and are connected in a conventional manner via fluid input
ports. A fluid
output port (described in more detail below) connects the heat exchanger 44 to
a nozzle
assembly 46 of the beer gun 16. The heat exchanger 44 also has conventional
ports and fittings
for connecting input and output refrigerant lines to the rack heat exchanger
34.
The vending stand 10 shown in the figures also has a refrigeration system
(shown
generally at 48 and described in more detail below) for cooling the interior
of the vending stand
10 and for cooling refrigerant for the heat exchangers 34, 44. To supply the
heat exchangers 34,
44 with cool refrigerant, conventional refrigerant supply lines 50, 52 run
from the refrigeration
system 48 to the heat exchangers 34, 44, respectively, and are connected to
the refrigeration
system 48 and the heat exchangers 34, 44 via fittings and ports as is well
known to those skilled
in the art. Similarly, conventional refrigerant return lines 54, 56 run from
the heat exchangers
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34, 44, respectively, and are connected to the refrigeration system 48 and the
heat exchangers
34, 44 via conventional fittings and ports.
To keep the kegs 22 and connected comestible fluid and refrigerant lines 30,
42, 50, 52,
54, 56 cool, the interior area of the vending stand 10 is preferably insulated
in a conventional
manner. With respect to the fluid lines 42 running outside of the vending
stand 10 to the
dispensing gun 16, these lines are preferably kept inside the vending stand 10
when the
dispensing gun 16 is not being used. Specifically, the fluid lines 42 can be
attached to a reel
device or any other conventional line takeup device (not shown) to draw the
fluid lines 42 inside
the vending stand 10 when the dispensing gun 16 is returned to a holder 58 on
the vending stand
10. Such devices and their operation are well known to those skilled in the
art and are therefore
not described further herein.
With reference to FIG. 3, the flow of beer through the present invention is
now described
in greater detail. As used herein and in the appended claims, the term "fluid
line" refers
collectively to those areas through which fluid passes from the source of
fluid (e.g., kegs 22) to
the dispensing outlets 70, 130. A "fluid line" can refer to the entire path
followed by fluid
through the system or can refer to a portion of that path.
As described above, a delivery line 30 runs from each keg 22 to the rack heat
exchanger
34 and is connected to fluid input lines on the rack heat exchanger 34 in a
conventional manner.
The delivery line 30 is preferably fitted with a valve 60 for at least
selectively restricting but
most preferably selectively closing the delivery line 30. For the sake of
simplicity, the valve 60
is preferably a conventional pinch valve, but can instead be a diaphragm valve
or any other
valve preferably capable of quickly closing and opening the delivery line 30.
The valve 60 can
be fitted over the delivery line 30 as is conventional in many pinch valves,
or can instead be
spliced into the delivery line 30 as desired.
As mentioned above, a fluid output line 38 runs from the rack heat exchanger
34 to each
nozzle assembly 40. Most preferably, the output line 38 and the connected
nozzle assembly 40
are an extension of the rack heat exchanger 34 at its fluid output port (not
shown). A purge line
62 preferably extends from the output line 38 or from nozzle assembly 40 as
shown in FIG. 3,
and is connected to the output line or nozzle assembly in a conventional
manner. The purge line
62 is preferably fitted with a purge valve 64 for selectively closing the
purge line 62. The purge
valve 64 is preferably also a pinch valve, but can instead be any other valve
type as described
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above with reference to the valve 60 on the delivery line 30. As will now be
described in more
detail, the nozzle assembly 40 is supplied with beer from the heat exchanger
44 and is actuatable
to open and close for selectively dispensing beer.
The nozzle assembly 40 (see FIG. 4) includes a housing 66, a valve 68 movable
to open
and close an dispensing outlet 70, and a fluid holding chamber or reservoir 80
defined at least in
part by the housing 66 and more preferably at least in part by the housing 66
and the valve 68.
The housing 66 is preferably elongated as shown in the figures. For reasons
that will be
described below, the housing 66, valve 68, and dispensing outlet 70 are
preferably shaped to
permit the valve 68 to move in telescoping relationship a distance within the
housing 66. In the
preferred embodiment shown in the figures, the housing 66, valve 68, and
dispensing outlet 70
have a round cross-sectional shape, thereby defining a tubular internal area
of the housing 66.
The valve 68 is preferably a plunger-type valve as shown in FIG. 4, where the
valve 68 provides
a seal against the inner wall or walls (depending upon the particular housing
66 shape) of the
housing 66 through a range of positions until an open position is reached.
Although one open
position is possible in such a valve, the valve 66 is more preferably movable
through a range of
open positions also, thereby providing for different sizes for the dispensing
outlet 70 and a
corresponding range of flow speeds from the dispensing outlet 70. To actuate
the valve 68, a
valve rod 72 is attached at one end to the valve 68 and extends through the
housing 66 to an
actuator 74 preferably attached to the housing 66. The actuator 74 is
preferably controllable by
a user or system controller 150 in a conventional manner to position the valve
68 in a range of
different positions in the housing 66. This range of positions includes at
least one open position
in which the dispensing outlet 70 is open to dispense beer and a range of
closed positions
defined along a length of the housing 66 in which the dispensing outlet 70 is
closed to prevent
the dispense of beer. One having ordinary skill in the art will appreciate
that the entire housing
66 of the nozzle assembly 40 need not necessarily be elongated or tubular in
shape. Where the
preferred plunger-type valve 68 is employed (other nozzle elements described
below being
capable of performing the functions of a plunger-type valve 68 as discussed
below), only the
portion of the housing 66 that meets with the valve 68 to provide a fluid-
tight seal through the
range of closed valve positions should be elongated, tubular, or otherwise
have a cavity therein
with a substantially constant cross-sectional area along a length thereof.
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The actuator 74 is preferably pneumatic, and is preferably supplied by
conventional lines
and conventional fittings with compressed air from an air compressor (not
shown), compressed
air tank (also not shown), or even from the tank 24 connected to and
pressurizing the kegs 22. It
will be appreciated by one having ordinary skill in the art that numerous
other actuation devices
and assemblies can be used to accomplish the same function of moving the valve
68 with
respect to the housing 66 to open the dispensing outlet 70. For example, the
actuator 74 need
not be externally powered to both extended and retracted positions
corresponding to open and
closed positions of the nozzle valve 68. Instead, the actuator 74 can be
externally powered in
one direction (such as toward an extended position pushing the nozzle valve 68
open) and
biased toward an opposite direction by the pressurized beer in the nozzle
assembly 40 in a
manner well known to those skilled in the art. As another example, the
pneumatic actuator 74
can be replaced by an electrical or hydraulic actuator or a mechanical
actuator capable of
moving the valve by gearing (e.g, a worm gear turning the valve rod 72 via
gear teeth on the
valve rod, a rack and pinion set, and the like), magnets, etc. In this regard,
the valve 68 need not
necessarily be attached to and be movable by a valve rod 72. Numerous other
valve actuation
elements and assemblies exist that are capable of moving the valve 68 to open
and close the
dispensing outlet. However, the actuation element or assembly in all such
cases is preferably
controllable over a range of positions to move the valve 68 to desired
locations in the housing
66. Such other actuation assemblies and elements fall within the spirit and
scope of the present
invention.
In highly preferred embodiments of the present invention, a trigger sensor 76
and a
shutoff sensor 78 are mounted at the tip of the nozzle housing 66 or (as shown
in FIG. 4) at the
tip of the valve 68. Both sensors 76, 78 are connected in a conventional
manner to a system
controller 150 for controlling the valves 60, 62, 76 to dispense beer from the
nozzle assembly 40
and to stop beer dispense at a desired time. Preferably, the actuation sensor
76 is a mechanical
trigger that is responsive to touch, while the trigger sensor 78 is an optical
sensor responsive to
the visual detection of beer or its immersion in beer. Of course, many other
well known
mechanical and electrical sensors can be used to send signals to the system
controller 150 for
opening and closing the valve 68 of the nozzle assembly 40. Such sensors
include without
limitation proximity sensors, motion sensors, temperature sensors, liquid
sensors, and the like.
However, the sensors used (and particularly, mechanical sensors such as the
trigger sensor 76 in
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the preferred embodiment of the present invention) should be selected to
operate in connection
with a wide variety of beer receptacles and receptacle shapes. For example,
where a selected
trigger sensor operates by detecting a bottom surface of a beer receptacle,
the sensor should be
capable of detecting bottom surfaces of all types of beer receptacles,
including without
limitation surfaces that are flat, sloped, opaque, transparent, reflective,
non-reflective, etc.
In a beer dispensing operation, a user places a vessel such as a glass or mug
beneath the
nozzle assembly 40 corresponding to the type of beer desired. The vessel is
raised until the
trigger sensor 76 is triggered (preferably by contact with the bottom of the
vessel in the
preferred case of a manual trigger sensor). Upon being triggered, the trigger
sensor 76 sends a
signal to the system controller 150 via an electrical connection thereto
(e.g., up the valve rod 72,
out of the actuator 74 or housing 66 and to the system controller 150, up the
housing 66 and to
the system controller 150, etc.) or transmits a wireless signal in a
conventional manner to be
received by the system controller 150. The system controller 150 responds by
closing the valve
60 on the delivery line 30 from the keg 22. At this stage, the keg 22,
delivery line 30, heat
exchanger 34, output line 38, and nozzle assembly 40 contain beer under
pressure near or equal
to keg pressure. This pressure is generally too large for proper beer dispense
from the nozzle
assembly 40. As such, the pressure at the nozzle assembly 40 is preferably
reduced to a
desirable amount based upon the desired dispense characteristics (e.g., the
amount of beer head
desired) and the beer type being dispensed. Pressure at the nozzle assembly 40
can be reduced
in several ways.
For example, the system controller 150 can send or transmit a signal to the
purge valve
64 to open the same for releasing beer out of the purge line 62. Valve
controllers responsive to
such signals are well known to those skilled in the art and are not therefore
described further
herein. The purge valve 64 is preferably open for a sufficient time to permit
enough beer to exit
to lower the pressure in the nozzle assembly 40. The amount of purge valve
open time required
depends at least in part upon the amount of pressure drop desired, the type of
beer dispensed,
and the dimensions of the purge line 62 and purge valve 64. Preferably, the
system controller
150 is pre-programmed with times required for desired pressure drops for
different beer types.
The user therefore enters the type of beer being dispensed via the controls
20, at which time the
system controller 150 references the amount of time needed to drop pressure in
the nozzle
assembly 40 to a sufficiently low level for proper beer dispense. After the
pressure in the nozzle
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assembly 40 has dropped sufficiently, the system controller 150 sends or
transmits a signal to
the purge valve 64 to close and sends a signal to the actuator 74 to open the
nozzle valve 68.
As another example, pressure in the nozzle assembly 40 can be reduced by
enlarging
some portion of the area within which the beer is contained. Although such
enlargement can be
performed, e.g., by expanding the fluid line or a portion of the heat
exchanger 34 (i.e., moving a
wall or surface defining a portion of the fluid line or heat exchanger 34), it
is most preferred to
enlarge the fluid holding chamber 80. Accordingly, the valve 68 is movable to
increase the size
of the fluid holding chamber 80 in the housing 66 of the nozzle assembly 40.
The valve
preferably defines a surface or wall of the fluid holding chamber. As
discussed above, the valve
68 is preferably movable through a range of closed positions in the nozzle
assembly 40, and
more preferably is in telescoping relationship within the housing 66. When the
system
controller 150 receives the trigger signal from the trigger sensor 76, the
system controller 150
sends or transmits a signal to the actuator to move the valve toward the
dispensing outlet 70.
This movement increases the volume of the fluid holding chamber 80 in the
nozzle assembly 40,
thereby lowering the pressure in the nozzle assembly 40. By the time the valve
68 reaches the
dispensing outlet 70 and opens to dispense the beer, the pressure within the
nozzle assembly has
lowered to a desired dispensing pressure.
Still other conventional pressure-reducing devices and assemblies can be used
to lower
the pre-dispense pressure in the nozzle assembly 40. For example, one or more
walls defining
the fluid holding chamber 80 can be movable to expand the fluid holding
chamber, such as by
one or more telescoping walls laterally movable toward and away from the
center of the fluid
holding chamber 80 prior to movement of the nozzle valve 68, a flexible wall
of the fluid
holding chamber 80 (such as an annular flexible wall) deformable to increase
the volume of the
fluid holding chamber 80, etc. A wall of the latter type can be formed, for
example, in a bulb
shape and be normally constricted by a band, cable, or other tightening device
and be loosened
prior to dispense to increase the volume of the fluid holding chamber 80. Such
other devices
and assemblies are well known to those skilled in the art and fall within the
spirit and scope of
the present invention.
It should be noted that more than one pressure reducing device or assembly can
be
employed to lower the nozzle dispense pressure to the desired level. The
nozzle assembly
shown in FIGS. 3 and 4, for example, includes the purge line 62 and purge
valve 64 assembly
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and also includes a telescoping nozzle valve 68. However, in practice only one
such device or
assembly is typically necessary. Therefore, where the most preferred
telescoping nozzle
assembly is employed as shown in FIGS. 3 and 4, the need for a purge line 62
and purge valve
64 is either reduced or eliminated. Also, where the purge line 62 and the
purge valve 64 are
employed as also shown in FIGS. 3 and 4, the need for a valve 68 having a
range of closed
positions is reduced or eliminated. In other words, the valve 68 can simply
have an open and a
closed position. Depending upon the speed at which the pressure reducing
device or assembly
operates and the dispense speed of the nozzle assembly, it is even possible to
eliminate the valve
60 on the delivery line 30 running from the keg 22. Specifically, a lower
pressure at or near the
nozzle assembly 40 does not necessarily reduce fluid pressure upstream of the
rack heat
exchanger 34 (i.e., in the delivery line 30) due to the response lag normally
experienced from a
pressure drop at a distance from the nozzle assembly. A pressure drop that is
sufficiently fast at
the nozzle assembly 40 can permit a user to dispense beer at or near a desired
dispense pressure
in the nozzle assembly before higher pressure upstream of the heat exchanger
34 has time to be
transmitted to the nozzle assembly 40, thereby eliminating the need to actuate
the pinch valve 60
on the delivery line 30 or eliminating the need for the pinch valve
altogether.
Pressure drop in the nozzle assembly 40 prior to dispense can be performed in
a number
of different manners as described above, including the preferred valve
arrangement shown in the
figures. Although such a plunger-type valve is preferred, other conventional
valve types can
instead be used (including without limitation pinch valves, diaphragm valves,
ball valves, spool
valves, and the like) where one or more of the earlier-described alternative
pressure reduction
devices are employed.
At substantially the same time or soon after the system controller 150 sends a
signal to
the actuator 74 to open the nozzle valve 68, the system controller 150 also
preferably activates
the shutoff sensor 78 (if not already activated). Preferably, the shutoff
sensor 78 is selected and
adapted to detect the presence of fluid near or at the level of the nozzle
valve 68 or the end of
the nozzle housing 66. The shutoff sensor 78 can perform this function by
detecting the
proximity of the surface of the beer in the vessel, by detecting its immersion
in beer in the
vessel, by detecting a temperature change corresponding to removal of the beer
from the sensor,
and the like. Most preferably however, the shutoff sensor 78 optically detects
its immersion in
the beer in a manner well known in the fluid detection art.
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The system controller 150 permits beer to be poured from the nozzle assembly
40 so
long as the system controller 150 does not receive a signal from the shutoff
sensor 78 indicating
otherwise. The nozzles 14 of the preferred embodiment of the present invention
are sub-surface
fill nozzles, meaning that beer is injected into the already-dispensed beer in
the vessel. Due to
the preferred shape of the nozzle valve 68 shown in FIGS. 3 and 4, beer exits
the dispensing
outlet 70 radially in all directions within the vessel, thereby distributing
the pressure of the beer
better (to help reduce carbonation loss and foaming) than a straight flow
dispense. It should be
noted, however, that flow from the dispensing outlet does not need to be
radial flow in all
directions, and can instead be flow in a stream, fan, or in any other flow
shape desired. After an
initial amount of beer has been poured into the vessel, the tip of the nozzle
assembly 40 is
preferably kept beneath the surface of the beer in the vessel. Additional beer
dispensed into the
vessel is therefore injected with less foaming and with less loss of
carbonation. When the user
is done dispensing beer into the vessel, the user drops the vessel from the
nozzle assembly 40.
The shutoff sensor 78 detects that it is no longer immersed in beer, and sends
a signal in a
conventional manner to the system controller 150. Upon receiving this signal,
the system
controller 150 sends a signal to the actuator 74 to return the nozzle valve 68
to a closed position,
thereby sealing the dispensing outlet 70 and stopping the dispense of beer.
By virtue of the above nozzle assembly arrangement, pressure can be maintained
throughout the system - from the kegs 22 to the nozzle valves 68. Most
preferably, the
equilibrium state of the system is pressure substantially equal to the storage
pressure of beer in
the kegs (or the "rack pressure"). Such pressure throughout the system
prevents loss of
carbonation in the system due to low or atmospheric pressures, prevents over-
carbonation due to
undesirably high pressures, enables faster beer dispense, and permits better
dispense control.
Several alternatives exist to the use of the trigger sensor 76 and the shutoff
sensor 78 on
the nozzle assembly for controlling beer dispense. For example, the nozzle
assembly 40 can be
operated directly by a user via the controls 20, in which case the user would
preferably directly
indicate the start and stop times for beer dispense. As another example where
the size of the
vessel into which beer is dispensed is known, this information can be entered
by a user into the
system controller 150 via the controls 20. In operation, the system is
triggered to start
dispensing beer by a trigger sensor such as the trigger sensor 76 discussed
above, by a user-
actuatable button on the controls 20, by one or more sensors located adjacent
the nozzle
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assembly for detecting the presence of a vessel beneath the nozzle 14 in a
manner well known to
those skilled in the art, and the like. Where a desired amount of beer is to
be dispensed, beer
dispense can be stopped in a number of different ways, such as by a shutoff
sensor like the
shutoff sensor 78 described above, one or more sensors located adjacent to the
nozzle assembly
40 for detecting the removal of the vessel from beneath the nozzle 14, by a
conventional
flowmeter located anywhere along the system from the keg 22 to the nozzle
valve 68 (and more
preferably at the dispensing outlet 70 or in the housing 66) for measuring the
amount of flow
past the flowmeter, or by a conventional pressure sensor also located anywhere
along the system
but more preferably located in the nozzle assembly 40 to measure the pressure
of beer being
dispensed. In both latter cases, dimensions of the nozzle assembly would be
known and
preferably programmed into the system controller 150 in a conventional manner.
For example,
if a flowmeter is used, the cross-sectional area of the nozzle 14 at the
flowmeter would be
known to calculate the amount of flow past the flowmeter. If a pressure sensor
is used, the size
of the dispensing outlet 70 when the nozzle valve 68 is open would be known to
calculate the
amount of flow through the dispensing outlet 70 per unit time. Using a
conventional timer 152
preferably associated with the system controller 150, the system controller
150 can then send a
signal to the actuator 74 to close the nozzle valve 68 after an amount of time
has passed
corresponding to the amount of fluid dispense desired (e.g., found by dividing
the amount of
fluid desired to be dispensed by the flow rate per unit time). Because the
pressure and flow rate
vary during dispensing operations, alternative embodiments employing a
flowmeter or pressure
sensor continually monitor beer flow or pressure, respectively, to update the
flow rate in a
conventional manner. When the desired amount of beer has been measured via the
flowmeter or
pressure sensor, the system controller 150 sends a signal to the actuator 74
to close the nozzle
valve 68.
Devices and systems for calculating flow amount such as those just described
are well
known to those skilled in the art and fall within the spirit and scope of the
present invention. It
should be noted, however, that such devices and systems need not necessarily
be used in
conjunction with the nozzle valve 68 as just described, but can instead be
used to control beer
supply to the nozzle assembly 40. For example, such devices and systems can be
used in
connection with a valve such as valve 60 upstream of the rack heat exchanger
34 to control fluid
supply to the nozzle assembly 40, which itself would preferably be timed to
open and close with
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or close to the opening and closing times of the upstream valve. Whether the
device or system
calculates flow based upon valve open time (like the pressure sensor example
described above)
or measured flow speed with the cross-sectional flow area known (like the
flowmeter example
also described above), control of valves other than the nozzle valve 68 can be
used to dispense a
desired amount of beer from the nozzle assembly 40.
Yet another manner in which a desired amount of beer can be dispensed from the
nozzle
assembly 40 is by closing a valve such as valve 60 upstream of the nozzle
assembly 40 and
dispensing all fluid downstream of the closed valve 60. The valve 60 can be
positioned a
sufficient distance upstream of the nozzle assembly 40 so that the amount of
beer from the valve
60 through the nozzle assembly 40 is a known set amount, such as 12 ounces, 20
ounces, and
the like. By closing the valve 60 and dispensing the fluid downstream of the
valve 60, a known
amount of beer is dispensed from the nozzle assembly 40. If shorter fluid line
distances
between the valve 60 and the nozzle assembly 40 are desired, the fluid line
can have one or
more fluid chambers (not shown) with known capacities that are drained after
the valve 60 is
closed. Additionally, multiple valves 60 located in different positions
upstream of the nozzle
assembly 40 can be employed to each dispense a different (preferably standard
beverage size)
fluid amount from the nozzle assembly 40. The user and/or system controller
150 can therefore
selectively close one of the valves corresponding to the desired dispense
amount. To assist in
draining the fluid line downstream of the valve 60 closed, the valve can have
a conventional
drain line or port associated therewith (e.g., on the valve 60 itself or
immediately downstream of
the valve 60) that opens when the valve 60 is closed and that closes when the
valve is opened.
Similarly, to assist in filling the fluid line downstream of the valve 60 when
the nozzle valve 68
is closed and the valve 60 is open after dispense, a conventional vent valve
or line can be
located on the nozzle assembly 40 and can open while the fluid line is filling
and close when the
fluid line has been filled.
Although valve control upstream of the nozzle assembly 40 can be used to
dispense a set
amount of beer, such an arrangement is generally not preferred due to inherent
pressure
variations and pressure propagation times through the system resulting in
lower dispense
accuracy. However, pressure variations and pressure propagation times are
significantly
affected by the particular location of the valve(s) 60 and the type and size
of heat exchanger 34
used. Therefore, the problems related to such valve control can be mitigated
by using heat
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exchangers having low pressure effects on comestible fluid in the system or by
locating the
valve(s) 60 between the heat exchanger 34 and the nozzle assembly 60.
It should be noted that because the amount of beer dispensed from the nozzle
assemblies
40 can be measured on a dispense by dispense basis via the flowmeter or the
timed pressure
sensor arrangements described above, the total amount of beer dispensed from
any or all of the
nozzle assemblies can be monitored in a conventional manner, such as by the
system controller
150. Among other things, this is particularly useful to monitor beer waste,
pilferage, and
consumer preferences and demand.
FIGS. 5 and 6 illustrate the refrigeration system of the present invention. In
contrast to
conventional vending stands, the present invention does not require an
insulated or refrigerated
keg storage area. Eliminating the need for a keg storage area refrigeration
system in lieu of the
heat exchanger refrigeration system described below represents a significant
cost and
maintenance savings and results in a much more efficient refrigeration system.
An insulated
and refrigerated keg storage area is preferred particularly in applications
where a keg is
dispensed over the period of two or more days. However, in high-volume
dispensing
applications such as concession stands at sporting events and festivals, kegs
are spent quickly
enough to eliminate refrigeration after tapping to prevent spoilage. A
refrigeration system for
cooling the keg storage area in the vending stand 10 illustrated in the
figures is not shown, but
can be employed if desired. Such systems and their operation are well known to
those skilled in
the art and are not therefore described further herein.
With reference first to FIG. 5, which is a schematic representation of the
refrigeration
system 48 of the present invention, the four primary elements of a
refrigeration system are
shown: a compressor 82, a condenser 84, an expansion valve (in the illustrated
preferred
embodiment, a triple-feed wound capillary tube 86), and an evaporator (in the
illustrated
preferred embodiment, the rack heat exchanger 34 or the dispensing gun heat
exchanger 44).
Although many different working fluids can be used in the refrigeration system
48, such as
Ammonia, R-12, or R-134a, or R-404a, the working fluid is preferably R-22.
In a vapor compressor refrigeration cycle such as that employed in the
preferred
embodiment of the present invention, the compressor 82 receives relatively low
pressure and
high temperature refrigerant gas and compresses the refrigerant gas to a
relatively high pressure
and high temperature refrigerant gas. This refrigerant gas is passed via gas
line 88 to the
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condenser 84 for cooling to a relatively high pressure and low temperature
refrigerant liquid.
Although several different condenser types exist, the condenser 84 is
preferably a conventional
air-cooled condenser having at least one fan for blowing air over lines in the
condenser to cool
the refrigerant therein. After passing from the condenser 84, the relatively
high pressure, low
temperature refrigerant liquid is passed through the triple feed wound
capillary tube 86 to lower
the pressure of the refrigerant, thereby resulting in a relatively low
pressure and low temperature
refrigerant liquid. This refrigerant liquid is then passed to the heat
exchanger 34, 44 where it
absorbs heat from the beer being cooled. The resulting relatively high
temperature and low
pressure refrigerant gas is then passed to the compressor 82 (via a valve 96
as will be discussed
below) for the next refrigeration cycle. Most preferably, the heat exchanger
34, 44 is connected
to the rest of the refrigeration system 48 by conventional releasable fittings
92 (and most
preferably, conventional threaded flair fittings) so that the unit being
refrigerated by the
refrigeration system 48 can be quickly and conveniently changed. Similarly,
the refrigerant
lines connected to the heat exchanger 34, 44 are preferably connected thereto
by conventional
releasable threaded flair fittings 94. It will be appreciated by one having
ordinary skill in the art
that such fittings can take any number of different forms. Such fittings, as
well as the fittings
and connection elements for connecting all elements of the refrigeration
system 48 to their lines
are well known to those skilled in the art and are not therefore described
further herein.
Any of the lines connecting the elements of the refrigeration system 48 can be
rigid.
However, these lines are more preferably flexible for ease of connection and
maintenance, and
preferably are made of transparent material to enable flow characteristics and
cleanliness
observation. In particular, where the refrigerant supply and return lines 50,
52, 54, 56 run to and
from the dispensing gun 16, these lines should be flexible to permit user
movement of the
dispensing gun 16. Such lines are well known in the refrigeration and air-
conditioning art. For
example, flexible automotive air conditioning hose can be used to connect the
heat exchanger 44
to the remainder of the refrigeration system 48.
The refrigeration system 48 of the present invention can be used to control
the
temperature at which beer is dispensed from the dispensing gun 16 and from the
nozzle
assembly 40. It is highly desirable to control the amount of cooling of the
heat exchanger 34, 44
in the present invention. As is well known in the art, the pressure of beer
must be kept within a
relatively narrow range for proper beer dispense, and this pressure is
significantly affected by
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the temperature at which the beer is kept. Although it is desirable to keep
the beer cool in the
nozzle assembly 40, most preferably the beer temperature is controlled by
control of the
refrigeration system 48 as described below. By controlling the temperature of
beer flowing
through the system by refrigeration system control, the pressure changes
called for by
movement of the nozzle valve 68 as described above also can be better
controlled, as well as the
pressure of beer in the system (an important factor in measuring beer dispense
as also described
above). For example, if a lower equilibrium beer pressure is desired in the
nozzle assembly 40
prior to moving the nozzle valve 68 to drop the beer pressure before beer
dispense, the system
controller 150 can control the refrigeration system (as described in more
detail below) to
increase cooling at the heat exchanger 34, thereby lowering beer pressure at
the nozzle assembly
40. Such control is useful in other embodiments of the present invention
described above for
controlling beer pressure and temperature in the system.
To control the refrigeration system 48, a conventional evaporator pressure
regulator
(EPR) valve 96 is preferably located between the heat exchanger 34, 44 and the
compressor 82.
The EPR valve 96 is connected in the refrigerant return line 54, 56 in a
conventional manner.
The EPR valve 96 measures the pressure of refrigerant in the refrigerant
return line 54, 56 (and
the heat exchanger 34, 44) and responds by either constricting flow from the
heat exchanger 34,
44 or further opening flow from the heat exchanger 34, 44. Either change
alters the pressure
upstream of the EPR valve 96 in a manner well known to those skilled in the
art. Specifically,
by adjusting the valve, the pressure within the heat exchanger 34, 44 can be
increased or
decreased. Increasing refrigerant pressure in the heat exchanger 34, 44 lowers
the refrigerant's
ability to absorb heat from the beer in the heat exchanger 34, 44, thereby
lowering the cooling
effect of the heat exchanger 34, 44 and increasing the temperature of beer
passed therethrough.
Conversely, decreasing refrigerant pressure in the heat exchanger 34, 44
increases the
refrigerant's ability to absorb heat from the beer in the heat exchanger 34,
44, thereby increasing
the cooling effect of the heat exchanger 34, 44 and lowering the temperature
of beer passed
therethrough. The pressure upstream of the EPR valve 96 can be precisely
controlled by
adjusting the EPR valve 96 to result in refrigerant of varying capacity to
cool, thereby precisely
controlling the temperature of beer dispensed and allowing the refrigeration
system 48 to run
continuously independently of loading placed thereupon. This is in contrast to
conventional
refrigeration systems for comestible fluid dispensers in that conventional
refrigeration systems
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generally must cycle on and off when the loading on such systems becomes
light. The EPR
valve is preferably connected to and automatically adjustable in a
conventional manner by the
system controller 150, but can instead be manually adjusted by a user if
desired. In this regard,
a temperature sensor (not shown) is preferably located within or adjacent to
the nozzle assembly
40, 46, the heat exchanger 34, 44, or the keg 22 to determine the temperature
of beer in the
system and to provide the system controller 150 with this information. The
system controller
150 can then adjust the EPR valve 96 to change the beer temperature
accordingly.
Another manner by which the refrigeration system 48 can be adjusted to control
cooling
of the heat exchanger 34, 44 is also shown in the schematic diagram of FIG. 5.
Specifically, a
bleed line 98 is preferably connected at the discharge end of the compressor
82 and at another
end to the refrigerant supply line 50, 52 running from the capillary tube 86
to the heat exchanger
34, 44. The bleed line 98 is fitted with a conventional bypass regulator 100
which measures the
pressure of refrigerant in the refrigerant supply line 50, 52 and which
responds by either keeping
the bleed line 98 shut or by opening an amount to bleed hot refrigerant from
the compressor 82
to the refrigerant supply line 50, 52. The bleed line 98 and bypass regulator
100 are preferably
connected to the compressor 82 and refrigerant supply line 50, 52 by
conventional fittings. Hot
refrigerant bled from the compressor 82 by the bypass regulator mixes with and
warms cold
refrigerant liquid in the refrigerant supply line 50, 52, thereby lowering the
refrigerant's capacity
to absorb heat from beer in the heat exchanger 34, 44 and raising the
temperature of beer
passing through the heat exchanger 34, 44. The amount of hot refrigerant gas
mixed with the
refrigerant in the refrigerant supply line 50, 52 can be precisely controlled
by the bypass
regulator to result in refrigerant of varying capacity to cool, thereby
precisely controlling the
temperature of beer dispensed and allowing the refrigeration system 48 to run
continuously
independently of loading placed thereupon. As mentioned above, this is in
contrast to
conventional refrigeration systems for comestible fluid dispensers in that
conventional
refrigeration systems generally must cycle on and off when the loading on such
systems
becomes light. The bypass regulator 100 is preferably connected to and
automatically
adjustable in a conventional manner by the system controller 150, but can
instead be manually
adjusted by a user if desired. In this regard, a temperature sensor (not
shown) is preferably
located within or adjacent to the nozzle assembly 40, 46, the heat exchanger
34, 44, or the keg
22 to determine the temperature of beer in the system and to provide the
system controller 150
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with this information. The system controller 150 can then adjust the bypass
regulator 100 to
change the beer temperature accordingly.
It should be noted that the EPR valve 96 and the bypass regulator 100 can take
many
different forms well known to those skilled in the art, each of which is
effective to open or close
the respective lines to change the pressure of refrigerant in the system or to
inject hot refrigerant
into a cold refrigerant line. These refrigerant system components act at least
as valves and most
preferably as regulators to open or close automatically in response to
threshold pressures being
reached in the refrigerant lines detected (thereby automatically keeping the
refrigerant system 48
operating at a capacity sufficient to maintain a desired beer temperature).
Although an EPR
valve 96 and a bypass regulator 100 are included in the preferred embodiment
of the present
invention illustrated in the figures, one having ordinary skill in the art
will recognize that system
operation can be controlled by one of these devices or any number of these
devices. Also, if
either or both of these devices are simply valves rather than regulators,
refrigeration system
control is still possible by measuring the temperature and/or pressure of beer
flowing through
the heat exchangers 34, 44 as described above and by operating the valves 96,
100 via the
system controller 150 in response to the measured temperature and/or pressure.
With reference to FIG. 6, the rack heat exchanger 34 of the preferred
embodiment of the
present invention can be seen in greater detail. The rack heat exchanger 34 is
preferably a plate
heat exchanger having at least one beer input port 102, one beer output port
104, one refrigerant
input port 106, and one refrigerant output port 108 in a conventional housing.
In the illustrated
preferred embodiment, the rack heat exchanger is a plate heat exchanger having
four separate
flow paths through the heat exchanger 34 for four different beers.
Accordingly, the illustrated
rack heat exchanger 34 has four different beer input ports 102 and four
different beer output
ports 104, and has one refrigerant input port 106 and one refrigerant output
port 108 for running
refrigerant through all sections of the rack heat exchanger 34. It will be
appreciated by one
having ordinary skill in the art that the rack heat exchanger 34 can be
divided into any number
of separate sections (beer flow paths) corresponding to any number of desired
beers run to the
dispensing rack 12, and that more refrigerant input and output ports 106, 108
can be employed if
desired. Indeed, the rack heat exchanger 34 can even have dedicated
refrigerant input and
output ports 106, 108 for each section of the rack heat exchanger 34.
Alternatively, the
dispensing rack can have a separate heat exchanger 34 with dedicated
refrigerant input and
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output ports 106, 108 for each beer fed to the dispensing rack 12. Plate-type
heat exchangers
having multiple fluid passageways are well known to those skilled in the art
and are not
therefore described further herein. As described above, a delivery line 30
runs to each fluid
input port from a respective keg 22 and is coupled thereto in a conventional
manner with
conventional fittings. Similarly, the refrigerant supply line 50 and the
refrigerant return line 54
run to the refrigerant input and output ports 106, 108, respectively, and are
coupled thereto in a
conventional manner with conventional fittings. Each output port 108 of the
rack heat
exchanger 34 preferably extends to the nozzle housing 66.
A problem that can arise in using conventional plate-type heat exchangers for
dispensing
comestible fluid is that such heat exchangers typically have a head space
therein. Head space is
undesirable in comestible fluid systems because such areas are hard to clean
(in some cases,
they never become wet or immersed in the fluid being cooled), create pressure
regulation
problems in the system, and can harbor bacteria growth and possibly even spoil
beer in the
system. With reference to FIGS. 6 and 6a, the head space 110 is an area of the
heat exchanger
interior that is at a higher elevation than the beer output ports 104, and is
not filled with fluid
during normal system operation. FIGS. 6 and 6a show the plate-type heat
exchanger of the
present invention in greater detail. As is known to those skilled in the art,
fluid to be cooled is
kept separated from refrigerant by one or more plates within the heat
exchanger, one side of
each plate being exposed to or immersed in the refrigerant while the other
side of each plate is
exposed to or immersed in the fluid being cooled. To prevent the problems
associated with head
space mentioned above, the rack heat exchanger 54 preferably has a vent port
113 at the top of
the rack heat exchanger 54. The vent port 113 has a vent valve 115 that can be
actuated to open
and close the vent port 113. The vent valve 115 can be any valve capable of
opening and
closing the vent port, but more preferably is a check valve only permitting
air and gas exit from
the rack heat exchanger 54. The rack heat exchanger 54 also preferably has a
sensor 117
capable of detecting the presence of liquid at the top of the rack heat
exchanger 54. The sensor
117 can one of many types, including without limitation an optical sensor for
detecting the
proximity of fluid in the head space of the rack heat exchanger 54, a liquid
sensor responsive to
immersion in liquid, a temperature sensor responsive to the temperature
difference created by
the presence or contact of liquid upon the sensor, a mechanical or electro-
mechanical liquid
level sensor, and the like. The vent port 113, vent valve 115, sensor 117, and
their connection
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and operation are conventional in nature. Although the vent valve 115 can be
manually opened
and closed (also in a conventional manner), most preferably the vent valve 115
is controlled by
the system controller 150 to which it and the sensor 117 are connected.
However, it should be
noted that the vent valve 115 and the sensor 117 can be part of a separately
powered and self-
contained electrical circuit that receives signals from the sensor 117 and
that controls the vent
valve 115 accordingly. Such circuits are well known to those skilled in the
art and fall within
the spirit and scope of the present invention.
In operation, the vent valve 115 is open to permit fluid exit from the rack
heat exchanger
54. When the sensor 117 detects the presence of liquid at the top of the rack
heat exchanger 54
(at a comestible fluid trigger level or a maximum fill level of the rack heat
exchanger), the
sensor 117 preferably sends or transmits one or more signals to the system
controller 150, which
in turn sends or transmits one or more signals to close the vent valve 115 and
to prevent fluid
from exiting the rack heat exchanger 54. Most preferably, the sensor 117 is
selected or
positioned so that the vent valve 115 will close just as the rack heat
exchanger 54 becomes filled
with beer. Depending upon the type of sensor 117 used, the sensor 117 can be
positioned in the
vent port 113 for detecting the initial entry of beer into the vent port 113,
or can even be
attached to or immediately beside the vent valve 115. By virtue of the venting
arrangements
just described, the system controller 150 can vent the space above the level
of beer in the rack
heat exchanger 54 at any desired time. This not only avoids above-described
problems
associated with head space, but it also permits easier cleaning. Specifically,
when cleaning fluid
is flushed through the system, the vent valve 115 and sensor 117 can be
operated to ensure that
the cleaning fluid contacts, flushes, and cleans all areas of the rack heat
exchanger 54.
Many other venting assemblies and elements are well known to those skilled in
the art
and can be employed in place of the vent port 113, vent valve 115, and sensor
117 described
above and illustrated in the figures. These other venting assemblies and
elements fall within the
spirit and scope of the present invention.
As an alternative to a venting assembly or device to address the problem of
rack heat
exchanger head space described above, the head space 110 can be filled or
plugged with a block
of material (not shown) having a shape matching the head space 110. Although
many materials
such as epoxy, plastic, and aluminum can be used, the block is preferably made
of easily
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cleaned material such as brass, stainless steel, teflon or other food grade
synthetic material, and
preferably fully occupies all areas of the head space 110.
With combined reference to FIGS. 4 and 6, another important feature of the
present
invention relates to the maintenance of beer temperature in the nozzle
assembly 40. As
described above, the rack heat exchanger 54 of the present invention has a
number of beer
output ports 104 extending therefrom. Each nozzle assembly 40 has an input
port 112 to which
one of the beer output ports 104 connects in a conventional manner (preferably
via conventional
fittings). Each output port 104 is preferably made of a highly temperature
conductive food
grade material such as stainless steel. Most preferably, each input port 112
and the walls of the
fluid holding chamber 80 in the nozzle assembly 40 are also made of highly
temperature
conductive food grade material.
The distance between the body of the rack heat exchanger 54 and the housing 66
of the
nozzle assembly 40 is preferably as short as possible while still providing
sufficient room for
vessel placement and removal to and from the nozzle assembly 40. Preferably,
this distance (in
the preferred embodiment shown in the figures, the combined lengths of the
beer output port
104 and the nozzle assembly input port 112 defining a fluid passage or fluid
line between the
body of the rack heat exchanger 54 and the nozzle assembly 40) is less than
approximately 12
inches (30.5 cm). More preferably, this distance is less than 8 inches (20.3
cm). Most
preferably however, this distance is between 1 and 6 inches (2.5-15.2 cm). The
nozzle assembly
40 is therefore an extension of the heat exchanger.
The distance between the body of the rack heat exchanger 54 and the housing 66
of the
nozzle assembly 40 is important for a particular feature of the present
invention: maintaining
the temperature of beer in the nozzle assembly 40 as near as possible to the
temperature of beer
exiting the rack heat exchanger 54. This function is also performed by the
preferably thermally
conductive material of the beer output port 104 and the nozzle assembly input
port 112.
Specifically, when beer flows through the nozzle assembly and is dispensed
from the dispensing
outlet 70, beer has an insufficient time to significantly change from its
optimal drinking
temperature controlled by the rack heat exchanger 54. When beer is not being
dispensed from
the nozzle assembly 40, it is most desirable to keep the beer at the optimal
drinking temperature.
Prior art beer dispensers are either incapable of keeping beer in the nozzle
sufficiently
cold for an indefinite length of time or keeping this beer refrigerated in an
efficient and
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inexpensive manner. However, in the present invention, the distance between
the refrigerating
element (i.e., the rack heat exchanger 54) and the fluid holding chamber 80 in
the nozzle
assembly 40 is preferably so short that fluid throughout the fluid holding
chamber 80 is kept
close to the temperature of beer at the rack heat exchanger 54 or exiting the
rack heat exchanger
54 by convective recirculation. Specifically, beer in the body of the rack
heat exchanger 34 or
in the beer output port 104 of the rack heat exchanger 54 is normally the
coldest from the rack
heat exchanger to the dispensing outlet 70 of the nozzle assembly 40, while
beer at the nozzle
valve 48 is the warmest because it is farthest from a cold source. A
temperature difference or
gradient therefore exists between beer in the body of the rack heat exchanger
34 and beer at the
terminal end of the nozzle assembly 40. By keeping the rack heat exchanger 34
close to the
housing 66 of the nozzle assembly 40 as described above, cooled beer from
around and within
the beer output port 104 of the rack heat exchanger 34 moves by convection
toward the fluid
holding chamber 80. Because cold fluid tends to sink, the cold fluid entering
the fluid holding
chamber migrates to the lowest part of the fluid holding chamber 80 - the
location of the
warmest beer in the nozzle assembly 40. The cold beer thereby mixes with and
cools the warm
beer. Because warm beer tends to rise, warm beer in the fluid holding chamber
80 rises therein
to a location closer to the cold source (the rack heat exchanger 34). This
convective
recirculation fully effective to maintain beer in the nozzle assembly cold
only for the relatively
short distances between the rack heat exchanger 34 and the fluid holding
chamber 80 described
above. Although not required to generate the beer cooling just described, the
preferred highly
temperature conductive material of the beer output port 104, the nozzle
assembly input port 112,
and the walls of the fluid holding chamber 80 in the nozzle assembly 40 assist
in distributing
cold from the rack heat exchanger 34, down the beer output port 104 and nozzle
assembly input
port 112, and down the fluid holding chamber 80. Cold is therefore preferably
distributed
downstream of the rack heat exchanger 34 by convective recirculation and by
conduction.
In the heat exchanger and nozzle assembly configuration described above and
illustrated
in the drawings, the rack heat exchanger 34 is capable of maintaining the
temperature difference
between beer in the rack heat exchanger 34 and beer in the fluid holding
chamber to within 5
degrees Fahrenheit. Where exchanger-to-nozzle assembly distances are within
the most
preferred 1-6 inch (2.5-15.2 cm) range, this temperature difference can be
maintained to within
2 degrees Fahrenheit. These temperature differences can be kept indefinitely
in the present
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invention. Although prior art systems exist in which a more distant cold
source run at a colder
temperature is employed to cool downstream beer, such systems operate with
mixed success at
the expense of significant energy loss and inefficiency, overcooling beer, and
creating large
temperature gradients along the fluid path (in some cases even dropping the
temperature of
elements in the system below freezing) - results that render the preferred
system temperature
and pressure control of the present invention difficult or impossible.
As an alternative a mounted nozzle assembly such as nozzle assemblies 40
described
above and illustrated in FIGS. 1-6, FIGS. 7 and 8 illustrate a portable nozzle
assembly 46 in the
form of a dispensing gun 16. With the exception of the following description,
the dispensing
gun 16 employs substantially the same components and connections and operates
under
substantially the same principles as the rack heat exchanger 34 and nozzle
assemblies 40
described above.
The dispensing gun 16 has a gun heat exchanger 44 to which are connected the
fluid
lines 42 from the kegs 22. Like the rack heat exchanger 34, the gun heat
exchanger 44 is
preferably a plate heat exchanger having multiple beer input ports 114 and
multiple beer output
ports 116 corresponding to the different beers supplied to the dispensing gun
16, a refrigerant
input port 118 and a refrigerant output port 120. The fluid lines 42 running
from the kegs 22 to
the dispensing gun 16 are each connected to a beer input port 114, while the
refrigerant supply
line 52 and the refrigerant return line 56 running between the refrigeration
system 48 to the
dispensing gun 16 are connected to the refrigerant input port 118 and the
refrigerant output port
120, respectively. All of the connections to the gun heat exchanger 44 are
conventional in
nature and are preferably established by conventional fittings.
Like the rack heat exchanger 34, the gun heat exchanger 44 preferably has
multiple fluid
paths therethrough that are separate from one another and a refrigerant path
that runs along each
of the multiple fluid paths to the beers therein. Heat exchangers (and with
reference to the
illustrated preferred embodiment, plate heat exchangers) having multiple
separate fluid
compartments and paths are well known to those skilled in the art and are not
therefore
described further herein.
The gun heat exchanger 44 preferably has a multi-port beer output valve 122
for
receiving beer from each of the beer output ports 116. The beer output ports
120 are preferably
shaped as shown to run from the body of the gun heat exchanger 44 to the beer
output valve 122
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to which they are each connected in a conventional manner (such as by
conventional fittings,
brazing, and the like). Alternatively, the beer output ports 116 can be
connected to the beer
output valve 122 by relatively short fluid lines (not shown) connected in a
conventional manner
to the beer output ports 116 and to the beer output valve 122.
The beer output valve 122 is preferably electrically controllable to open one
of the beer
output ports 116 running from the gun heat exchanger 44 to the beer output
valve 122. Many
different valve types capable of performing this function are well known to
those skilled in the
art. In the illustrated preferred embodiment, the beer output valve 122 is a
conventional 4-input,
1-output rotary solenoid valve. The beer output valve 122 is preferably
electrically connected to
a control pad 124 preferably mounted on a face of the gun heat exchanger 44.
Alternatively, the
beer output valve 122 can be electrically connected to the controls 20 on the
vending stand 10
via electrical wires (not shown) running along the fluid and refrigerant lines
42, 52, 56. In the
preferred embodiment shown in the figures, the control pad 124 has buttons
that can be pressed
by a user to operate the beer output valve 122 in a conventional manner.
The nozzle assembly 46 of the dispensing gun 16 is substantially like the
nozzle
assemblies 40 of the dispensing rack 12 described above and operates in much
the same manner.
However, the housing 126 preferably has a dispense extension 128 extending
from the
dispensing outlet 130 thereof. The fluid exit port defined by the opening of
the nozzle assembly
from which beer exits the nozzle assembly is therefore moved a distance away
from the
dispensing outlet 130. When the nozzle valve 132 is moved toward and through
the dispensing
outlet 130 by the actuator 134 to dispense beer, beer flows through the
dispensing outlet 130,
into the dispense extension 128, and down into the vessel to be filled. The
dispense extension
128 is used to help guide beer into the vessel, but is not a required element
of the present
invention. However, where the dispense extension 128, a trigger sensor 136,
and a shutoff
sensor 138 are used on the dispensing gun 16 (operated in the same manner as
in the dispensing
rack nozzle assembly 40 described above), the trigger sensor 136 and the
shutoff sensor 138 are
preferably mounted on the end of the dispense extension 128 as shown.
As an alternative to electronic or automatic control of the nozzle valve 132,
it should be
noted that the motion of the nozzle valve 132 can be manually controlled by a
user if desired.
For example, the user can manipulate a manual control such as a button on the
dispensing gun
16 to mechanically open the nozzle valve 132. The nozzle valve can be biased
shut by one or
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more springs, magnets, fluid pressure from the pressurized comestible fluid in
the nozzle, etc. in
a manner well known to those skilled in the art. By manipulating the manual
control, the user
preferably moves the nozzle valve 132 through its closed positions to lower
pressure in the
holding chamber 140, after which the nozzle valve 132 opens to dispense the
beer at its lower
pressure. As another example, the nozzle valve 132 can be actuated by a user
manually as
discussed above, after which time an actuator (of the type described earlier)
controls how long
the nozzle valve 132 remains open. It should also be noted that such manual
control over nozzle
valve 132 actuation can be applied to the nozzle valves 68 of the rack nozzle
assemblies 40 in
the same manner as just described for the dispensing gun 16.
In operation, a user grasps the dispensing gun 16 and moves the dispensing gun
16 over
a vessel to be filled with beer. Preferably by operating the control pad 124
on the dispensing
gun 16, the user changes the type of beer to be dispensed if desired. If the
type of beer to be
dispensed is changed, a signal is preferably sent from the control pad 124
directly to the beer
output valve 122 (or from the control system in response to the control pad
124) to open the beer
output port 116 corresponding to the beer selected for dispense. The
dispensing gun 16 is then
triggered either by user manipulation of a control on the control pad 124 or
on the controls 20 of
the vending stand, or most preferably by the trigger sensor 136 in the manner
described above
with regarding to the dispensing rack nozzle assemblies 40. At this time, the
empty fluid
holding chamber 140 is filled with the selected beer. Immediately thereafter
or substantially
simultaneous therewith, the nozzle valve 132 is preferably moved toward the
dispensing outlet
130 to reduce the pressure in the holding chamber as described above.
Although not preferred, the fluid holding chamber 140 can be fitted with a
vent port,
valve, and sensor assembly operating the in the same manner as the vent port,
valve, and sensor
assembly 113, 115, 117 described above with reference to the rack heat
exchanger 34. This
assembly would preferably be located at the top of the fluid holding chamber
140 for venting the
empty fluid holding chamber and to permit faster beer flow into the fluid
holding chamber 140
from the beer output valve 122. Such an assembly could be manually controlled,
but more
preferably is electrically connected to the beer output valve 116, control pad
124, controls 20, or
system controller 150 to open with the beer output valve 122 and to close
after the fluid holding
chamber is full or substantially full.
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After the desired amount of beer has been dispensed into the vessel, the valve
132
preferably moves to close the dispensing outlet 130 and the beer output valve
preferably moves
to a closed position. Most preferably, the beer output valve 122 closes first
to permit sufficient
time for the fluid holding chamber 140 to empty. In this regard, the vent
port, valve, and sensor
assembly (not shown) mentioned above can be opened to assist in draining the
fluid holding
chamber 140. When the valve 132 is returned by the actuator 134 to close the
dispensing outlet
130, the nozzle assembly 46 is ready for another dispensing cycle.
In the operation of the dispensing gun 16 as just described, the fluid holding
chamber
140 is normally empty between beer dispenses. If such were not the case, beer
held therein
would be mixed with beer exiting from the beer output valve 122 in the next
dispense. While
this is not necessarily undesirable if the same beer is being dispensed in the
next dispensing
cycle, it is undesirable if a different beer is selected for the next
dispensing cycle. Although not
as desirable as the above-described operation, an alternative dispensing gun
operation maintains
beer within the fluid holding chamber 140 after each dispense by keeping the
beer output valve
open while the nozzle valve 132 is open and after the nozzle valve 132 is
closed. Such
dispensing gun operation is therefore much like the nozzle assembly operation
of the dispensing
rack nozzle assemblies 40 described above. The beer output valve 122 is
preferably controlled
by the system controller 150 to remain open through successive dispenses of
the same beer.
However, if another beer is selected for dispense via the control pad 124 or
the vending stand
controls 20, the fluid holding chamber 140 is purged of the beer therein
before the next
dispense. This purging can be performed by the system controller 150 via a
user-operable
control on the control pad 124 or vending stand controls 20 or automatically
by the system
controller 150 each time an instruction is received to actuate the beer output
valve 122 to open a
different beer output port 116. During a purging operation, the beer outlet
valve 122 is closed
and then the nozzle valve 132 is opened briefly to let the waste beer drain
from the fluid holding
chamber 140. Immediately thereafter, the actuator 134 preferably moves the
nozzle valve 132
back to a closed position and the beer output valve 122 is actuated to open
the beer output port
116 corresponding to the beer to be dispensed. Alternatively, the nozzle
housing 126 can be
provided with a conventional vent port and vent valve (not shown) which are
preferably
controlled by the system controller 150 to open to drain the beer in the fluid
holding chamber
140 prior to opening the beer output valve 122. Whether drained by opening the
nozzle valve
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132 or by opening a vent valve in the nozzle housing 126, it is also possible
to purge the fluid
holding chamber 140 under pressure from the new beer selected for dispense by
briefly opening
the nozzle valve 132 or the vent valve while the beer output valve 122 is
open.
In the most highly preferred embodiments of the dispensing gun 16 the beer
output valve
122 is located immediately downstream of the heat exchanger as shown in FIGS.
7 and 8. Such
a design minimizes the waste of beer from purging the dispensing gun 16
between dispenses of
different beer types when the holding chamber 140 is filled with beer between
dispenses.
However, it is possible (though not preferred) to located the beer output
valve 122 in another
location between the keg 22 and the nozzle assembly 46. For example, a multi-
input port, single
output port valve can instead be located upstream of the gun heat exchanger
44. Preferably, all
four fluid lines 42 would be connected in a conventional manner to input ports
of the valve,
which itself would be connected in a conventional manner to a beer input port
of the gun heat
exchanger 44. The valve would be controllable in substantially the same manner
as the beer
output valve 122 of the preferred dispensing gun embodiment described above.
The advantage
provided by this design is that the gun heat exchanger 44 only needs to have
one beer fluid path
therethrough because only one beer is admitted into the gun heat exchanger 44
at a time. This
results in a simpler, less expensive, and easier to clean gun heat exchanger
44. However, the
disadvantage of this design is that draining or purging the gun heat exchanger
44 between
dispenses of different beers is more difficult. Where draining is not possible
to empty the gun
heat exchanger 44 and the nozzle assembly 46, the beer can be purged by
flowing the newly-
selected beer through the dispensing gun 16 or by pushing the beer through the
heat exchanger
44 by compressed air or gas (e.g., supplied from the tank 24) via a pneumatic
fitting on the gun
heat exchanger 44. Although each purge does waste an amount of beer, the
combined beer
capacity in the gun heat exchanger 44 and the nozzle assembly 46 is relatively
small.
The advantages provided by the dispensing gun 16 of the preferred embodiment
described above and illustrated in the figures are much the same as those of
the of the nozzle
assembly 40 and heat exchanger 34 of the dispensing rack 12. For example, the
pressure
reduction control of beer within the holding chamber 140 of the nozzle
assembly 46 prior to
opening the dispensing outlet 130 provides fast flow rate with minimal foaming
and carbonation
loss. As another example, the close proximity of the nozzle assembly 46 to the
gun heat
exchanger 44 provides the same convective recirculation cooling effect as that
of the dispensing
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rack nozzle assemblies described earlier, thereby keeping beer to a controlled
cool temperature
up to the dispensing outlet 130. It should be noted that the more compact
nature of the
dispensing gun 16 (when compared to the nozzle assemblies 40 of the dispensing
rack 12)
preferably provides for a shorter distance between the body of the gun heat
exchanger 44 and
the housing 126 of the nozzle assembly 46. This distance is preferably between
1-6 inches (2.5-
15.2 cm), but more preferably is between approximately 1-3 inches (2.5-7.6
Cm). By virtue of
the shorter distances, the maximum temperature difference between the beer in
the fluid holding
chamber 140 and beer at the gun heat exchanger 44 is less than about 10
degrees Fahrenheit, and
more preferably is less than about 5 degrees Fahrenheit. Still shorter heat
exchanger-to-nozzle
assembly distances are possible to result in narrower temperature differences
when the size of
the components in the dispensing gun 16 are smaller. Most preferably, the
nozzle assembly of
the dispensing gun 16 is substantially the same size as the nozzle assembly 40
in the dispensing
rack 40. However, if desired, smaller nozzle assemblies and smaller heat
exchangers can be
used in the dispensing gun 16 at the expense of cooling rate and/or flow rate.
It should also be
noted that the refrigeration system control and operation discussed above with
reference to FIG.
applies equally to cooling operations of the gun heat exchanger 44.
The relative orientation of the gun heat exchanger 44 and the nozzle assembly
46 as
shown in FIGS. 7 and 8 are not required to practice the present invention. The
arrangement
illustrated, with the gun heat exchanger 44 alongside the nozzle assembly 46,
with hand grip
forms 142 on the sides of the gun heat exchanger 44, etc. is presented only as
one of many
different relative orientations of the gun heat exchanger 44 with respect to
the nozzle assembly
46. One having ordinary skill in the art will recognize that many other
relative orientations are
possible, such as the nozzle assembly 46 being oriented at an angle (e.g., 90
degrees) with
respect to its position shown in FIG. 7 and with beer exiting from the beer
output valve 122 to
the nozzle assembly 46 via an elbow pipe. This and other dispensing gun
arrangements fall
within the spirit and scope of the present invention.
In addition to these advantages provided by the dispensing gun 16, an equally
significant
advantage is the fact that the dispensing gun 16 is hand-held and portable.
Although dispensing
guns are known in the art for dispensing various comestible fluids, their use
for many different
applications has been very limited. A primary limitation is due to the fact
that comestible fluids
in prior art dispensing gun lines will become warm after a period of time
between dispenses.
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With no way to cool this comestible fluid before it is dispensed, the vendor
must either waste
the warmed fluid or attempt to serve it to a customer. In short, dispensing
guns for many
comestible fluids are not acceptable due to the chance of fluid warming in the
lines between
dispenses. This is particularly the case for comestible fluids such as beer
that are generally not
served over ice. The dispensing gun 16 of the present invention addresses this
problem by
providing a cooling device (the gun heat exchanger 44) at the dispensing gun
16. Therefore,
even if comestible fluid becomes warm in the fluid lines 42, the same fluid
exits the dispensing
gun 16 at a desired and controllable cold temperature. For applications in
which a large amount
of time can pass between comestible fluid dispenses, the fluid lines 42 are
preferably drawn into
and stored within a refrigerated storage as described above. The only
limitation on use of the
dispensing gun 16 to dispense comestible fluids is therefore the spoil rate of
the comestible fluid
in its storage vessel (keg 22).
The dispensing gun 16 described above and illustrated in the figures is a
multiple-beer
dispensing gun. It should be noted, however, that the dispensing gun 16 can be
adapted to
dispense only one beer. Specifically, the beer gun 16 can have one beer input
port 114 to which
one fluid line 42 running to a keg 22 is coupled in a conventional manner.
Such a dispensing
gun 16 would therefore preferably have one beer output port 116 running
directly to the nozzle
assembly 46, and would not therefore need to have the beer output valve 122
and associated
wiring employed in the dispensing gun 16 described above. The dispensing gun
16 would
operate in substantially the same manner as a heat exchanger 34 and nozzle
assembly 40 of the
dispensing rack 12, with the exception of only one fluid line, one beer input
port, and one beer
output port associated with the heat exchanger. Preferably however, the
dispensing gun 16
would at least have a manual dispense button (not shown) for manually
triggering the actuator
134 to open the dispense outlet 130. The dispensing gun of the preferred
illustrated embodiment
is capable of selectively dispensing any of four beers supplied thereto.
However, following the
same principles of the present invention described above, any number of beers
can be supplied
to a dispensing gun 16 for controlled dispensed therefrom (of course, calling
for different
numbers of ports and different valve types depending upon the number of beers
supplied to the
dispensing gun 16). The alternative embodiments of the elements and operation
described
above with reference to the rack heat exchanger 34 and the nozzle assemblies
40 of the
dispensing rack 12 apply equally as alternative embodiments of the dispensing
gun 16.
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Conversely, the dispensing rack 14 described above can be modified to operate
in a
manner similar to the multi-fluid input, single output design of the
dispensing gun 16.
Specifically, rather than have a dedicated nozzle assembly 40 for each beer
output port 104 as
described above and illustrated in the figures, the dispensing rack 14 can
have a beer outlet
valve to which the beer outlet ports 104 are connected in a manner similar to
the beer outlet
valve 122 of the dispensing gun 16. The nozzle assembly 40 would preferably be
similar and
would operate in a similar manner to the nozzle assembly 46 of the dispensing
gun 16 illustrated
in FIG 7. However, the controls for such a system would preferably be located
at the vending
stand controls 20 rather than on the rack heat exchanger 34. The alternative
embodiments of the
elements and operation described above with reference to the dispensing gun 16
apply equally
as alternative embodiments of the rack heat exchanger 34 and nozzle assembly
40.
As mentioned above, a significant problem in existing comestible fluid
dispensers is the
difficulty in keeping the fluid dispenser clean. Many comestible fluids
(including beer) are
particularly susceptible to bacterial and other microbiological growth.
Therefore, those areas of
the fluid dispensers that come into contact with comestible fluid at any time
during dispenser
operation should be thoroughly and frequently cleaned. However, even thorough
and frequent
cleaning is occasionally inadequate to prevent comestible fluid spoilage and
contamination.
Particularly in those preferred embodiments of the present invention that rely
upon sub-surface
filling of comestible fluid, it is highly desirable to provide a manner by
which surfaces exposed
to air are constantly or very frequently sterilized. An apparatus for
performing this function is
illustrated in FIG. 9. This apparatus relies upon ultraviolet light to
sterilize surfaces of the
dispensing system in the present invention, and includes an ultraviolet light
generator 144
powered in a conventional manner and connected to different areas of the
dispensing system.
By way of example only, the ultraviolet light generator 144 of FIG. 9 is shown
connected to a
nozzle assembly 40 in the dispensing rack 12 and to the top of the rack heat
exchanger 34.
Conventional ultraviolet light sterilizing devices have been limited in their
application
due in large part to space requirements of such devices. However, this problem
is addressed in
the present invention by the use of conventional fiber optic lines 146
transmitting ultraviolet
light from the ultraviolet light generator 144 to the surfaces to be
sterilized. Ultraviolet light
generators and fiber-optic lines are well known to those skilled in the art,
as well as the manner
in which fiber-optic lines can be connected to a light source for transmitting
light to a location
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remote from the light source. Accordingly, at least one fiber-optic line 146
is connected in a
conventional manner to the ultraviolet light generator 144, and is secured in
place in a
conventional manner on or adjacent to the surface upon which the ultraviolet
light is to be shed.
In a preferred embodiment of the present invention, two fiber-optic lines 146
run from the
ultraviolet light generator 144 (which can be located within the vending stand
10 or in any other
location as desired) to locations beside the housing 66 of the nozzle assembly
40 in the
dispensing rack 12. The fiber-optic lines 146 preferably terminate at
distribution lenses 148 that
distribute ultraviolet light from the fiber-optic lines 146 to the exterior
surface of the housing 66.
Distribution lenses 148 and their relationship to fiber-optic lines to
distribute light emitted from
fiber-optic lines is well known to those skilled in the art and is not
therefore described further
herein. Most preferably, a number of fiber-optic lines 146 run from the
ultraviolet light
generator 144 to distribution lenses 148 positioned and secured in a
conventional about the outer
surface of the housing 66. The number of fiber-optic lines 146 and
distribution lenses 148
positioned about the housing 66 is determined by the amount of surface desired
to be sterilized,
but preferably is enough to shed ultraviolet light upon the entire outside
surface of the housing
66.
As also shown in FIG. 9, a series of fiber-optic lines 146 preferably run to
distribution
lenses 148 mounted in a conventional manner within the holder 58 for the
dispensing gun 16.
Although it is possible to run fiber-optic lines to the dispensing gun 16
itself, more preferably
the fiber-optic lines 146 run to the dispensing gun holder 58. Like the
distribution lenses 148
about the nozzle assembly 40, the distribution lenses 148 shown on the holder
58 of the
dispensing gun 16 receive ultraviolet light from the fiber-optic lines 146 and
disperse the
ultraviolet light received. In this manner, the fiber-optic lines 146 shed
ultraviolet light upon the
surfaces of the dispensing gun 16 (and most preferably, the exterior surfaces
of the nozzle
housing 66).
Fiber-optic lines can be run to numerous other locations in the dispensing
system to
sterilize surfaces in those locations. As shown in FIG. 9, fiber-optic lines
can be run to one or
more distribution lenses located at the top of the kegs 22 to sterilize
interior surfaces defining
head spaces therein. Fiber-optic lines can also or instead run to distribution
lenses mounted in
locations around the nozzle housing 126 and the dispense extension 128 of the
dispensing gun
16, to locations around the dispensing outlets 70, 130 to sterilize the
interior ends of the nozzle
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housings 66, 126, to locations within or at the end of the dispense extension
128 of the
dispensing gun 16 to sterilize the interior surfaces thereof, etc. Any place
where a head space
forms in the dispensing systems of the present invention (and those of the
prior art as well) are
locations where fiber-optic lines can be run to shed sterilizing ultraviolet
light upon head space
surfaces.
It should be noted that although distribution lenses 148 are preferred to
distribute the
ultraviolet light from the fiber-optic lines 146 to a surface to be
sterilized, distribution lenses are
not required to practice the present invention. Ultraviolet light can instead
be transmitted
directly from the fiber-optic line 146 to the surface to be sterilized. In
such a case, the amount
of surface area exposed to the ultraviolet light can be significantly smaller
than if a lens 148 is
used, but may be particularly desirable for sterilizing surfaces in relatively
small spaces. Also,
fiber-optic lines 146 represent only one of a number of different ultraviolet
light transmitters
that can be used in the present invention. For example, the fiber-optic lines
146 can be replaced
by light pipes if desired. As is well known to those skilled in the art, light
pipes have the ability
to receive light and to distribute light radially outwardly along the length
thereof. This light
distribution pattern is particularly useful in shedding sterilizing
ultraviolet light upon a number
of surfaces in manners not possible by fiber optic lines. For example, the
fiber-optic lines 146
running to the housings 66, 126 of the nozzle assemblies 40, 46 can be
replaced by conventional
light pipes which are wrapped around the nozzle assemblies 40, 46 or which run
alongside the
nozzle assemblies 40, 46. Light pipes can be run to any of the locations
previously described
with reference to the fiber-optic lines, and can even be run through the fluid
lines of the system
to sterilize inside surfaces thereof, if desired.
The number and locations of the fiber-optic lines 146 and the distribution
lenses 148
shown in FIG. 9 are arbitrary and are shown by way of example only. It will be
appreciated by
one having ordinary skill in the art that any number of fiber-optic lines,
distribution lenses, light
pipes, or other ultraviolet light transmitting devices can be used in any
desired location within or
outside of the comestible fluid dispensing apparatus.
To further facilitate easy and thorough cleaning of the present invention, all
components
of the fluid system are preferably made of a food grade metal such as
stainless steel or brass,
with the exception of seals, fittings, and valve components made from food
grade plastic or
other synthetic material as necessary. In highly preferred embodiments of the
present invention,
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the exterior surfaces of the nozzle housings 36, 126 and the dispense
extension 128 are teflon-
coated to facilitate better cleaning. If desired, other surfaces of the
apparatus that are
susceptible to bacteria or other microbiological growth can also be teflon-
coated, such as the
inside surfaces of the nozzle housings 36, 126 and the dispense extension 126,
the surfaces of
the nozzle valves 68, 132, and the like.
The embodiments described above and illustrated in the figures are presented
by way of
example only and are not intended as a limitation upon the concepts and
principles of the
present invention. As such, it will be appreciated by one having ordinary
skill in the art that
various changes in the elements and their configuration and arrangement are
possible without
departing from the spirit and scope of the present invention as set forth in
the appended claims.
For example, each of the preferred embodiments of the present invention
described above and
illustrated in the figures employs a plate heat exchanger 34, 44 to cool the
comestible fluid
flowing therethrough. A plate heat exchanger is preferred in the application
of the present
invention due to its relatively high efficiency. However, one having ordinary
skill in the art will
appreciate that many other types of heat exchangers can be used in place of
the preferred plate
heat exchangers 34, 44, including without limitation shell and tube heat
exchangers, tube in tube
heat exchangers, heatpipes, and the like.
Also, each of the embodiments of the present invention described above and
illustrated
in the figures has one or more kegs 22 stored in a refrigerated vending stand
10. It should be
noted, however, that the present invention does not rely upon refrigeration of
the source of
comestible fluid to dispense cold comestible fiuid. Because comestible fluid
entering the nozzle
assembly 40, 46 has been cooled by the associated heat exchanger 34, 44, the
temperature of the
comestible fluid upstream of the heat exchangers 34, 44 is relevant only to
the amount of work
required by the refrigeration system 48 supplying the heat exchangers 34, 44
with cold
refrigerant. Therefore, the kegs 22 can be tapped and dispensed from the
apparatus of the
present invention at room temperature, if desired. Essentially, the present
invention replaces the
extremely inefficient conventional practice of keeping large volumes of
comestible fluid cold
for a relatively long period of time prior to dispense with the much more
efficient process of
quickly cooling comestible fluid immediately prior to dispense using
relatively small and
efficient heat exchangers 34, 44.
