Note: Descriptions are shown in the official language in which they were submitted.
CA 02261866 2002-02-28
APPARATUS FOR THE DISPENSING OF HEATED
VISCOUS FOOD PRODUCT
BACKGROUND OF THE INVENT10N
The present invention relates to an apparatus for dispensing viscous fluids,
particularly food~products.
In the food service industry, there are a wide variety of devices that are
used to
dispense viscous food products. Such dispensers are commonly found in
restaurants,
convenience stores, and other commercial eating establishments. Many viscous
products, such as cheese sauces and ice cream toppings, do not flow well at
room
temperature, so these dispensers are often heated to maintain the product in a
flowable
condition.
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A typical heated dispenser uses a pump, and a connecting nozzle tube to
transfer the product from a heated product container housed within the
dispenser to the
user. The food product travels from the receptacle, through the nozzle tube,
and is
dispensed by the opening a valve at the nozzle. The use of such a dispensing
apparatus, however, has a number of disadvantages. Because the pump,
receptacle,
and nozzle, are in direct contact with the food product, each must frequently
be
dismantled and cleaned because of concern over contamination and bacterial
spoilage,
especially when the dispenser is used with dairy products. Many state health
laws
often mandate a daily cleaning of dispensers which store and dispense dairy
products.
Products most often used in the dispensers become more viscous and
tend to congeal as they cool. To properly clean the pump following use, the
pump
frequently must be soaked to loosen encrusted materials. The shape of the pump
often makes it extremely difficult to rid the pump of all particles, thus
providing an
excellent growth habitat for pathogens. Similarly, the nozzle being of small
diameter is
difficult to clean. This problem is exacerbated by the prior art devices
heating the
nozzle during operation causing the food product to strongly adhere to the
insides
surface of the nozzle. Proper cleaning of the nozzle is difficult because of
the collected
product build-up and the shape of the nozzle. Moreover, the exterior end of
the nozzle,
which extends outwardly from the dispenser, is typically comprised of
stainless steel, a
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good conductor of heat. The hot nozzle is capable of injuring the unwary user
of the
dispenser.
Overall cleaning of the dispenser cannot be accomplished without considerable
downtime caused, for example, by withdrawing the pump subassembly from within
the
product receptacle. Ordinarily, the pump subassembly is located inside the
dispenser
and has one end of the nozzle tube attached to it. Dismantling of many
dispenser parts
is required to remove the pump subassembly in order to clean the product
receptacle.
Any electrical connection, waterproof or otherwise, inhibits this cleaning
operation.
Finally, the pump, receptacle, and nozzle are in direct contact with the food
product;
therefore, they must be made of material such as stainless steel that is
accepted by the
authorities for being in contact with the food product.
Attempts have been made to address some of these concerns by using the bag-
in-box technology common in the beverage dispensing industry. For example,
soft
drink syrups, bulk milk, and wine is packaged in flexible bags. These packages
have
been successfully used for holding and dispensing liquids which will flow
readily at
room temperature when the dispensing valve is opened. However, they have not
worked well for containing and dispensing viscous products which will not
readily flow
under the force of gravity.
When bag-in-box packages are used for viscous products, pumps, pressure
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CA 02261866 2002-02-28
chambers, or similar equipment is needed to force the food product from the
bag. An
example of the pressure chamber used with a bag-in-box type of apparatus is
found in
U.S. Patent No. 4,796,788, issued January 10, 1989, and assigned to Liqui-Box
Corporation. Such dispensers, however, have their own attendant disadvantages,
including the expense of moving the food product.
In commonly assigned U.S. Patent No. 5,803,317 issued on September 8,
1998, an alternative system for dispensing viscous food products was
introduced
that incorporates the use of a peristaltic type of pump. The viscous food
product is packaged in a flexible bag having an elongated discharge tube
extending
therefrom. The dispenser includes a receptacle having an outlet opening in the
front,
lower portion thereof. The sealed food product container is seated in the
receptacle so
that the discharge tube extends from the front, lower portion of the
receptacle through
the outlet openirig. The pump is secured beneath the receptacle so that the
discharge
tube passes through the pump, and cooperates with the discharge tube to
provide flow
of the food product. The pump described in the co-pending application is a
peristaltic
pump that uses a rotor which driven at a predetermined speed by an electric
motor. A
plurality of pinch rollers are mounted on the periphery of the rotor and
rotate about
axes parallel to the axis of rotation of the rotor. The discharge tube is
supported by an
arcuate stator positioned near the rotor periphery. Thus, as the rotor
rotates, the
individual pinch rollers progressively impinge on the discharge tube,
compressing the
discharge tube against the stator, creating a peristaltic movement of the food
product
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within the discharge tube. In this manner, a predetermined volume of food
product is
moved axially through the discharge tube and is dispensed at a rate determined
by the
speed of rotation of the rotor.
In the dispenser described in the aforementioned co-pending application, the
food product is heated by conduction through the material of the receptacle
including
structure encompassing the tube. The portion of the receptacle adjacent the
product
bag is made of a heat-conducting material and is heated by an electric heater
positioned within the dispenser. Additionally, the portions of the dispenser
adjacent the
discharge tube are made of a heat-conducting material to ensure that product
within
the discharge tube is also maintained at the proper temperature and that the
food
material is free flowing at all points within the dispenser, including those
portions of the
elongated tube most remote from the receptacle. These portions may be heated
through conduction from the walls of the receptacle or by a separate heating
element.
20
The heating of the food product by conduction, however, does not always
provide optimal uniform heating and may also make the internal and external
receptacle surfaces extremely hot. Such hot surfaces increase the difficulty
of
handling the dispenser.
Therefore, it is an object of the present invention to provide for a viscous
food
dispenser that heats the food product at all points during the passage of the
food
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product from the receptacle to the point of exit from the receptacle, thereby
ensuring
the food product remains in a free flowing state.
It is another object of the present invention to provide for a heated viscous
food
dispenser that reduces the likelihood that a user will come into contact with
extremely
hot surfaces.
It is a further object of the present invention to provide for a heated
viscous food
dispenser that provides for more uniform heating of the food product while
resident
within the dispenser.
It is still a further object of the present invention to provide a receptacle
that is
easily removed from the dispenser for simple loading of the food product and
cleaning.
The foregoing and other objects and advantages will become apparent to those
skilled in the art upon a reading of the following description of a preferred
embodiment
of the present invention.
6
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SUMMARY OF THE INVENT10N
The present invention is generally directed to the dispensing of a liquid or
viscous food product, and is particularly advantageous when the product to be
dispensed does not flow well at room temperature but flows easier at an
elevated
temperature. Food products that may be dispensed by this invention include
cheese
sauce, dessert toppings, and syrups. Such food products are often contained in
a
flexible bag that is housed within the dispenser. The bag is connected to and
communicates with the exterior of the dispenser by a flexible hose. The food
stuff is
l0 moved and dispensed by controlled peristaltic action on the flexible hose.
Substantially, the entire bag and flexible hose is heated by convection,
thereby
providing more uniform heating of the food product, ensuring the product is in
a free-
flowing state at all points of its passage from receptacle through the tube,
and
eliminating the need for heat-conducting surfaces. The dispenser of the
present
invention also has a removable receptacle constructed to facilitate the
convection
heating of the bag and loading of the food product within the dispenser.
BRIEF DESCRIPT10N OF THE DRAWINGS
Figure 1 is perspective view of the heated dispensing apparatus of the present
invention;
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Figure 2 is an alternate perspective view of the dispensing apparatus of
Figure
1, wherein the product receptacle has been removed to show the heating
element;
Figure 3 is a perspective view of a flexible bag used for storing food product
that
is dispensed by the present invention;
Figure 4 is a detailed view of the port assembly that attaches to the flexible
bag
of Figure 1, allowing for dispensing of the food product;
Figure 5 is a detailed view of the peristaltic pump assembly of the dispensing
apparatus of Figure 1;
Figure 6 is a partial front elevation view of the pump assembly of Figure 5
wherein the pump pieces are in an open position;
Figure 7 is a partial front elevation view of the pump assembly of Figure 5
wherein the pump pieces are in a closed position;
Figure 8 is a top sectional view taken along line 8-8 of Figure 5; and
Figure 9 is a schematic view of a gravity fed dispenser incorporating the
present
invention.
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DESCRIPT10N OF THE PREFERRED EMBODIMENTS
Referring generally to Figures 1 and 2, it may be seen that the dispenser is
shown generally by the character numeral 10 and includes a dispenser housing
11,
food container basket 13, and pump housing 15. As stated above, the basket 13
is
designed to receive a disposable flexible pouch or bag adapted to be attached
to a
disposable flexible hose that is threaded through a pump assembly mounted
within the
pump housing 15. It is important to note that the pump housing 15 is
preferably
mounted toward the front of the dispenser 10, facilitating loading and
unloading of the
bag and flexible hose. This in effect bifurcates the internal volume of the
dispenser 10
such that the heating components (as described below) are located to the rear
of the
dispenser 10 while the pumping and dispensing components are located toward
the
front of the dispenser 10.
Figures 3 and 4 illustrate the structure of the bag and hose to be used with
the
dispenser of the present invention. A disposable, thin-walled, flexible bag 12
contains
the food product to be dispensed and defines an aperture 18 for dispensing.
The
flexible bag 12 is made of plastic or another suitable material that can
withstand heat,
i.e. temperatures in excess of 140 degrees Fahrenheit. Secured to the aperture
18 is a
port assembly 20 that is adapted for fluid-tight connection to the flexible
bag 12. A cap
24 is locked to the port assembly 20 by a downwardly sloped lip 25 around the
circumference of the cap 24, which is tightly received in a complementary
groove 22 on
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CA 02261866 1999-02-12
the inner surface of the port assembly 20, thereby providing a tight seal
between the
port assembly 20 and the cap 24.
The cap 24 further includes a nipple 26. A flexible discharge tube 30, having
an
inner diameter slightly less than the outer diameter of the nipple 26, is
secured to the
nipple 26, preferably by pressing the nipple 26 into the tube 30. The distal
end 32 of
the discharge tube 30 is sealed, thereby providing a sealed container of
product that is
ready for storage and shipment. As will be further explained, once the sealed
product
bag 12 has been seated in the dispenser, the discharge tube 30 is cut or
otherwise
opened near its distal end 32, allowing flow of the food product through the
discharge
tube 30.
Referring back to Figures 1 and 2, it may be seen that the dispenser housing,
preferably made of a washable, food-grade plastic, includes a base 44,
vertical side
walls 38, a top 39, and a hinged front door 36. The side walls 38, top 39, and
hinged
front door 36 define an internal cavity 35 for receiving and storing the
product basket
13. This basket 13 is easily inserted into and removed from the internal
cavity 35
when the front door 36 of the housing 34 is in an open position.
The basket 13 has a substantially vertical front wall 58, a substantially
vertical
back wall 59, and left and right side walls 62a, 62b. The front wall 59
preferably
defines a vertical slot 54. The basket 13 also has a bottom wall 63 that is
sloped
CA 02261866 1999-02-12
downward and toward the front wall 58. As shown in the Figures, the side and
bottom
walls 62a, 62b, 63 are preferably slotted, or otherwise open around the bag,
to allow for
the heated air to flow unimpeded about the bag. This is an important function
in that it
is essential that the food stuff in the bag be maintained at a temperature
level sufficient
to permit free flowing of the food product out of the bag and that the heating
is uniform
about the bag.
Although not shown in the Figures, the product receptacle alternatively may be
a
closed container having an outlet opening that is operatively connected to a
flexible
discharge tube. Such an embodiment is used when the food product is not
contained
in the preferred product bags. The food product can be poured directly into
the
receptacle before it is placed within the internal cavity 35 defined by the
housing 11.
As shown in Figure 4, a heating assembly 68 is positioned within the internal
cavity 35 and preferably at the rear of the dispenser 10 for heating the food
product.
The heating assembly 68 includes a housing 69 which encloses an electrical
heating
element 70. An intake fan 71 draws air into the housing 69. The air passes
overs the
heating element 70 and is then discharged through a lower opening 72 in the
housing
69 into the internal cavity 35 of the dispenser 10. In this manner, heated air
is
continually circulated into the internal cavity 35 around the basket 13 and
food product,
maintaining the food product at an elevated temperature.
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A thermostat (not shown) may also be included with the heating assembly 68. In
combination with a switching mechanism, such a thermostat can be used to
selectively
activate and deactivate the heating element 70 and fan 71, thereby allowing
the food
product to be maintained within a specific, predetermined temperature range.
For
example, many dessert toppings require the temperature to be maintained within
a
range of 110-120 degrees Fahrenheit.
As stated above, the preferred structure of the dispenser 10 is such that the
heating assembly 68 is located to the rear of the dispenser 10, behind the
pump base
76. It is essential, however, that the air heated by the heating assembly 68
also be
directed to and circulated about the flexible tube 30 carrying and dispensing
the
viscous material, along the entire length of the tube 30 from the aperture 18
of the bag
12 to the distal end 32 of the discharge tube 30.
Referring to Figures 1, 2 and 5, a pump base 76 is mounted beneath the
internal
cavity 35 and is adapted to support the two-piece pump housing 15. A passage
79
aligned with the outlet opening 64 of the basket 13 extends through the pump
housing
15 to receive the flexible discharge tube 30 when the bag 12 of food product
is
positioned in the basket 13. As illustrated in Figure 2, a duct 73, shown in
dashed
lines, extends from within the heating assembly housing 69, under the floor on
which
the basket 13 rests, and to the pump base 76. This duct 73 directs heated air
from the
heating assembly 68 along the length of the discharge tube 30, thereby
ensuring that
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the food product contained in the discharge tube 30 is maintained within the
predetermined temperature range. As best shown in Figure 5, the duct 73 has
two
outlet openings, a first opening 73a that directs air onto the discharge tube
30 where it
enters the passage 79 defined by the pump housing 15, and a second opening 73b
that
directs air onto the discharge tube 30 near where it exits the pump housing
15. This
structure ensures that heated air flows along substantially the entire length
of the tube
30 even that portion thereof positioned within the pump housing 15.
Although the duct 73 described above is the preferred structure for directing
heated air to the discharge tube 30, other conduits, vents, or similar
structures through
or around the pump base 76 may be used. The key is to transfer heat by
circulating the
heated air around or through the pump base 76 to the discharge tube 30,
thereby
providing uniform heat to the tube 30 and maintaining the product contained in
the tube
30 at the proper temperature.
The pump housing 15 includes two pieces 78a and 78b which cooperate to form
a stator. A rotor 90 is mounted for rotation on the pump base 76 and is
operably
connected to a drive shaft 88 that extends from a motor 89 (shown in Figure
5). The
motor 89 turns the drive shaft 88 and rotor 90 at a preselected speed. The
first pump
piece 78a is stationary while the second pump piece 78b is slidably mounted on
the
pump base 76 to slide toward and away from the rotor 90.
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The rotor 90 defines a circumferential groove 91. A plurality of pinch rollers
94
(shown in Figure 6-7) are mounted in the groove 91 for free rotation. The
rollers 94
are evenly distributed around the circumference of the rotor 90. While three
pinch
rollers 94 are used in this preferred embodiment, more or fewer pinch rollers
94 could
be used. The axis of rotation of each pinch roller 94 is parallel to the
longitudinal axis
of the drive shaft 88 of the rotor 90. Also, the pinch rollers 94 preferably
have the same
diameter and are arranged with their central axes near the outside edge of the
rotor 90
so that a portion of each roller 94 extends radially beyond the edge of the
rotor 90.
Thus, upon rotation of the rotor 90, the respective rollers 94 will with orbit
in a plane
about the axis of the drive shaft 88, and if frictionally restrained during
rotation of the
rotor, with rotate about their own axes.
As stated, the second pump piece 78b is mounted for sliding movement toward
or away from the rotor 90. As best shown in Figure 8, this is preferably
accomplished
by a plurality of shoulder bolts 85 which pass through slots defined by the
rear wall of
the second pump piece 78b, and screw into the pump base 76. These shoulder
bolts
85 are appropriately sized to hold the second pumping piece 78b against the
pump
base 76, but also allow the second pump piece 78b to slide laterally on the
shoulder
bolts 85 as permitted by the slots. Furthermore, in this preferred embodiment,
a disk
(not shown) is eccentrically rotatably mounted by a shoulder bolt to form a
cam within
an opening 83 defined by the second pump piece 78b. A cam handle 87 extends
from
the cam to enable a user to rotate the cam. Rotation of this cam causes the
second
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CA 02261866 1999-02-12
pump piece 78b to move toward or away from the rotor 90.
Referring now to Figures 6 and 7, as discussed above, the passage 79 for
receiving a discharge tube 30 extends between first and second pump pieces
78a, 78b
and around the rotor 90 in the second pump piece 78b. With the second pump
piece
78b slid away from the rotor 90, the discharge tube 30 can be inserted into
the passage
79. With the discharge tube 30 in position in the passage 79 and the second
pump
piece 78b slid into a closed position (toward rotor 90 and against the first
pump piece
78a), the spacing between the passage 79 and the rotor 90 is such that the
pinch
rollers 94 will compress or pinch the discharge tube 30. As the rotor 90
rotates,
respective pinch rollers 94 will contact and pinch the discharge tube 30,
forming a
peristaltic pump wherein the food product confined within the discharge tube
30 is
propelled longitudinally along the discharge tube 30 and out the open end of
the
discharge tube 30. It is preferable that the individual pinch rollers 94
sufficiently block
flow through the discharge tube when the pump is not operating so that a
separate
valve is not needed. Thus, one function of the pump is to act as a normally
closed
pinch valve to prevent the heated viscous food product from flowing out of the
dispenser when the dispenser is in a non-dispensing state.
To prepare the dispenser 10 for dispensing of the food product, the cam handle
87 is rotated, causing the second pump piece 78b to slide into an open
position. The
front door 36 of the dispenser 10 is opened, and the product basket 13 is
removed. A
CA 02261866 1999-02-12
bag 12 of food product is placed in the basket 13 with the discharge tube 30
being fed
through the slot 54 and out the outlet opening 64. The basket 13 with its
contents is
returned to the internal cavity 35 of the housing 11. The discharge tube 30 of
the
product bag 12 is then passed through the passage 79 of the pump housing 15.
The
closed end 32 of the tube 30 extends from the passage 79 at the bottom of the
pump
housing 15. The pump housing 15 is closed by rotation of the cam handle 87,
and the
second pump piece 78b is moved toward the rotor 90 so that the pincher rollers
94
contact the discharge tube 30. The closed end 32 of the discharge tube 30 is
then cut
off, and the front door 36 is closed. Once the food product has been heated to
the
predetermined temperature range, the product is discharged by activating the
motor 89,
which in turns rotates the rotor 90. As shown in Figures 3-5, a button 99 on
the front of
the dispenser 10 activates the motor 89. Once the button 99 is released, the
motor 89
shuts off, and the flow of the food product ceases. As an alternative, the
dispenser 10
may be equipped with a timing circuit that is triggered by the button 99,
providing for
activation of the motor 89 for a predetermined time period, thereby dispensing
a set
quantity of food product. When all of the food product is dispensed, the
second pump
piece 78b is moved away from the rotor, releasing the discharge tube 30. The
front
door 36 is opened, and the product basket 13 is removed. The product bag 12 is
removed from the basket 13 and disposed of, and the basket 13 is ready to
receive a
new product bag 12. Since the product remains in the bag 12 and discharge tube
30,
no part of the food product contacts the interior of the dispenser 10 and thus
no clean
up of the dispenser or pump is required.
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The present invention thus provides a dispensing device that addresses thQ
problems of inconsistent heating, meets all of the objectives stated above,
and provides
for simple handling of the food product. Moreover, the convective heating
system of
the present invention eliminates hot conductive surFaces, allowing the
dispenser 10,
including the basket 13, to be primarily manufactured from food-grade
plastics. The
removable basket 13 allows for simplified loading and unloading of the food
product,
and further facilitates cleaning. The structure of the present invention
allows the flow
of heated air to reach essentially all portions of the dispensing tube and the
bag within
l0 the basket to ensure the free flow of the food product at all locations
within the
dispenser.
While a peristaltic pump is a preferred component to cause the heated viscous
food stuff to be metered from the dispenser, it should be understood that the
beneficial
aspects of using an entirely disposable bag and elongated tube along with the
direct
heating of the elongated tube over substantially its entire length may also be
realized in
gravity fed types of dispensers. Such gravity fed dispensers would preferably
use a
simple, normally closed pinch type valve that manually opens and closes the
tube. The
schematic of Figure 9 illustrates a gravity fed type of dispenser 100 with a
receptacle
102 for receiving a bag 104 of viscous food product. An elongated tube 106 is
attached to the bag 104 and threaded through tube support members 108 into a
valve
structure 110 exposing the distal end 106a of tube 106. As before the tube is
cut or
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otherwise opened at its distal end. Valve 110 is normally biased into a closed
position,
but is manually operable by a user into an open position for the dispensing of
the food
product under gravity. However, as applicant has noted above with respect to
dispensers with pumps, the tube becomes cooler nearer the distal end due to
the
insulation provided by the support members, allowing the food product to
thicken, thus
often impeding the free flow of the viscous food product in this region of the
tube. To
ensure the continuous free flow of the food product from the bag 104 through
the entire
length of the tube 106, applicant has determined that the heat be directed
along the
entire length of the tube 106 to ensure that the viscosity of the food product
allows the
free flow needed. As illustrated schematically in Figure 9, a heat assembly
112
creates heat energy that may be directed to the bag 104 and the tube 106 by
conduction or preferably convection as shown by arrows 114. When done
convectionally, it is important that the circulation of heated air be directed
into the
support members 108 so that the tube is heated almost to its distal end. Valve
110 can
be any of a variety of pinch type valves that is operated by a user so that
the user can
dispense a predetermined amount of food product. Although it is preferable to
manually
open the valve, there may be situations in which it is desirable to use an
automatic
valve such as a solenoid operated valve that is open for a preset time period.
It is understood that changes may be made in the construction and arrangement
if the various components of the present invention. For example, while the
preferred
peristaltic pump is of the type described, other and different peristaltic
pumps, such as
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CA 02261866 1999-02-12
a sliding disk type of peristaltic pump, may also be used without departing
from the
spirit and scope of the invention as defined in the appended claims. Also,
while the
preferred structure for directing heated air to the discharge tube 30 is a
duct 73 that
extends from the heating assembly 68 through the pump base 76, other conduits,
vents
or other structures may be used to circulate the heated air around or through
the pump
base 76 to the discharge tube 30 without departing from the spirit and scope
of the
invention as defined in the appended claims.
19
