U.S. patent application number 10/689397 was filed with the patent office on 2004-04-29 for control methods for popping popcorn.
This patent application is currently assigned to Gold Medal Products Co.. Invention is credited to Weiss, Ronald R..
Application Number | 20040081732 10/689397 |
Document ID | / |
Family ID | 27498905 |
Filed Date | 2004-04-29 |
United States Patent
Application |
20040081732 |
Kind Code |
A1 |
Weiss, Ronald R. |
April 29, 2004 |
Control methods for popping popcorn
Abstract
Apparatus and methods for popping popcorn comprise a heated
kettle which is controlled and monitored according to the
temperature of the kettle. The kettle is initially heated to a
start cook temperature and a buzzer and light alert an operator to
add uncooked popcorn and oil to the kettle which lowers the
temperature of the kettle below a predetermined start temperature
and initiates a cooking cycle. An oil pump system is enabled at the
initiation of the cooking cycle for adding oil to the kettle. As
the popcorn and oil cook, the kettle temperature increases and
passes through a predetermined dump temperature and the kettle
automatically tilts and dumps the cooked popcorn. After the dump,
the kettle temperature increases to the start cook temperature
again and the buzzer and light are activated to alert the operator
to add another batch of ingredients for consecutive batches of
popcorn.
Inventors: |
Weiss, Ronald R.; (Okeana,
OH) |
Correspondence
Address: |
WOOD, HERRON & EVANS, LLP
2700 CAREW TOWER
441 VINE STREET
CINCINNATI
OH
45202
US
|
Assignee: |
Gold Medal Products Co.
Cincinnati
OH
|
Family ID: |
27498905 |
Appl. No.: |
10/689397 |
Filed: |
October 20, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10689397 |
Oct 20, 2003 |
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10283723 |
Oct 30, 2002 |
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10283723 |
Oct 30, 2002 |
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10041195 |
Jan 8, 2002 |
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6534103 |
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10041195 |
Jan 8, 2002 |
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09420479 |
Oct 19, 1999 |
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6352731 |
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09420479 |
Oct 19, 1999 |
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09212667 |
Dec 16, 1998 |
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6000318 |
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09212667 |
Dec 16, 1998 |
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08910756 |
Aug 13, 1997 |
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5871792 |
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08910756 |
Aug 13, 1997 |
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08633580 |
Apr 17, 1996 |
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5743172 |
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08633580 |
Apr 17, 1996 |
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08345303 |
Nov 28, 1994 |
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5694830 |
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Current U.S.
Class: |
426/445 |
Current CPC
Class: |
G07F 17/0078 20130101;
G07F 17/0085 20130101; A23L 7/187 20160801 |
Class at
Publication: |
426/445 |
International
Class: |
A23B 004/03 |
Claims
I claim:
1. A method of cooking a first batch of popcorn in a heated kettle
wherein kettle heating elements are controlled by an electronic
control receiving a temperature responsive signal from a heat
sensor on said kettle, said method comprising: energizing said
elements when said kettle is cold, maintaining delivery of energy
to said kettle until said sensor signals said control that a first
temperature has been reached, and then reducing said energy,
generating a signal when said kettle reaches a second higher
loading temperature, and thereafter loading corn and oil into said
kettle and popping popcorn.
2. The method of claim 1 including the step of dumping popcorn from
said kettle when said kettle reaches a dump temperature
substantially the same as said second temperature.
3. A method as in claim 2 including cooking a second batch of
popcorn by the subsequent cooking steps of sensing a third
temperature lower than said first temperature and reducing the
delivery of energy to said elements upon said sensing of said third
temperature and thereafter loading corn and oil into said kettle
when said second higher temperature is reached.
4. A method as in claim 1 including generating a first signal
observable by an operator upon said kettle's reaching said second
temperature to indicate the kettle is ready for loading of corn and
oil, and a second signal upon said kettle's reaching a
predetermined temperature indicating popping is complete and the
kettle can be dumped.
5. A method as in claim 1 wherein said popcorn is popped in a
period of about 3.0 to 3.5 minutes from the time corn and oil is
loaded into the kettle to the time a predetermined dump temperature
is reached and the corn is popped.
6. A method as in claim 1 wherein temperature of said kettle
declines when corn and oil is loaded therein and wherein said
method includes: electronic controlling of said heating elements to
cause said kettle to reach a dump temperature substantially equal
to said second temperature within a time of about 3.0 to 3.5
minutes wherein popped corn can then be dumped from said
kettle.
7. A method of cooking said popcorn including the method steps of
electronically measuring a dose of oil for use in popping a batch
of popcorn, including electronically controlling a pump for pumping
a measure of oil from an oil supply into a container, the method
comprising the steps of: placing an electronic control into a learn
mode, electronically energizing said pump into a pump cycle and
dispensing oil into a predetermined measured receptacle, stopping
said pump cycle when a predetermined oil measure is dispensed,
electronically recording said pump cycle, and thereafter
automatically controlling said pump to operate in subsequent cycles
to dispense the same measure of oil, when said pump is
energized.
8. A method of popping popcorn comprising the steps of: heating a
kettle to a first temperature and cycling the kettle heat about
said first temperature, loading corn and oil into said kettle,
raising the temperature of the kettle to a second predetermined
kettle dump temperature in a popping cycle time period from about
3.0 to about 3.5 minutes from the time corn and oil is loaded into
the kettle until the second predetermined dump temperature is
reached.
9. A method as in claim 8 including the step of dumping popcorn
from said kettle when said second dumping temperature is
reached.
10. A method as in claim 8 including generating an alarm when said
second dump temperature is reached.
11. A method as in claim 8 including generating an alarm when said
first temperature is reached.
12. A method as in claim 8 including the steps of generating alarms
when said first temperature is reached and when said second dump
temperature is reached.
13. A method as in claim 8 including automatically tilting said
kettle, upon first energizing said kettle from a cold start, until
said first temperature is reached to signal that said kettle is not
ready to be loaded with corn and oil.
14. A method as in claim 8 including popping a plurality of popcorn
types in the same kettle and comprising the further steps for a
second type of corn of: heating said kettle to a third temperature
and cycling the kettle heat about said third temperature; loading
another type of corn and oil into said kettle; raising the
temperature of said kettle to a fourth predetermined kettle dump
temperature in a popping cycle from said third temperature, and
wherein said first and second temperatures comprise one set of
temperatures, said third and fourth temperatures comprise a second
set of different temperatures and further comprising the step of
selecting the first or second set of temperatures prior to
initiating a popping cycle.
15. An electronic control for a popcorn popping kettle having
heating elements for heating a popping surface of the kettle to pop
popcorn kernels when kernels and oil are placed in the kettle and
which popped kernels are then dumped from the kettle, said
electronic control comprising: a thermocouple disposed on said
kettle for sensing kettle temperature; an electronic circuit for
operating said heating elements by connecting them to a source of
energy in response to a first sensed temperature by said
thermocouple and by disconnecting them from said source of energy
responsive to a second higher sensed temperature by said
thermocouple; said thermocouple being operably interconnected to
said control for activating and deactivating said elements in
response to said temperatures sensed by said thermocouple to raise
the temperature of said popping surface from a reduced temperature
occurring when kernels are loaded thereon to a dump temperature
when said kernels are substantially popped; and wherein said
predetermined temperatures are selected to cause the kettle's
popping surface to reach a desired dump temperature throughout a
cycle duration from popcorn kernel and oil kettle loading through
popped popcorn dumping of about 3.0 to about 3.5 minutes.
16. Apparatus as in claim 15 wherein said cycle duration is
substantially the same for the first batch of popcorn from a cold
start as for subsequent batches of popcorn from a kettle retaining
heat from prior batches.
17. The improvement of claim 15 wherein said thermocouple is
disposed on a portion of said kettle removed from said popping
surface, and wherein said thermocouple signals said control to
activate and deactivate said heating elements in response to
sensing respective temperatures as a function of said first and
second predetermined temperatures.
18. The improvement of claim 15 further including an alarm
operatively coupled to said electronic control for signaling
optimum time for first loading popping corn kernels and oil into
said kettle and for dumping popped popcorn from said kettle at the
end of a cycle when said dump temperature is reached.
19. The improvement of claim 15 wherein substantially all the
kernels added to the kettle together are popped within a cycle of
about 3.0 minutes to about 3.5 minutes.
20. The improvement of claim 19 wherein the popping of kernels
within said dump cycle is independent of decreased energy source
capacity and variations in the quantity of popcorn and oil added to
the kettle from one cycle to another.
21. The improvement of claim 15 herein said heating elements are
energized to raise the kettle to a higher kettle temperature upon
first start from a cold kettle as compared to raising the kettle to
a lower kettle temperature for subsequent cycles of popping.
22. Apparatus as in claim 15 further including an electronic
control for dispensing measured amounts of oil after a first
learned dispensing cycle wherein a pump is started to dispense an
amount of oil into a measured receptacle and then stopped and said
cycle is recorded by said control and thereafter repeated upon
subsequent pump energizing to dispense like measured amounts.
23. A method of popping corn in a plurality of batches from batches
of corn and oil beginning with a cold start batch and then
subsequent batches, including the step of: raising the kettle
temperature after loading a subsequent batch of corn and oil to a
dump temperature by energizing heat elements and heating the kettle
to one rise temperature and deenergizing the elements while the
kettle temperature climbs beyond said one rise temperature; and for
a cold start batch, energizing the heat elements and heating the
kettle to another rise temperature higher than said one rise
temperature before deenergizing said elements while said kettle
temperature climbs beyond said another rise temperature.
24. A method as in claim 23 including the step of loading a first
batch of corn and oil into a kettle from a cold start at a
temperature higher than a dump temperature.
25. A method as in claim 24 wherein a plurality of subsequent
batches of corn and oil are loaded into said kettle at a
temperature substantially equal to said dump temperature.
Description
RELATED APPLICATIONS AND PRIORITY
[0001] This application is a continuation in part application of
U.S. patent application Ser. No. 09/212,667, filed Dec. 16, 1998,
entitled "Apparatus for Popping Popcorn," which application in turn
is a divisional application of Ser. No. 08/910,756, filed Aug. 13,
1997, and entitled "Method for Popping Popcorn," now U.S. Pat. No.
5,871,792, which application in turn is a divisional application of
application Ser. No. 08/633,580, filed Apr. 17, 1996, and entitled
d "Automatic Popcorn Popper with Thermal Controller," now U.S. Pat.
No. 5,743,172, which application, in turn, is a
continuation-in-part application of application Ser. No.
08/345,303, filed Nov. 28, 1994, and entitled "Automated Corn
Popper," now U.S. Pat. No. 5,694,830, which applications and issued
patents are incorporated herein by reference in their entirety.
FIELD OF THE INVENTION
[0002] This invention relates generally to popcorn poppers and more
specifically to a automatic or manual popcorn poppers which produce
popcorn in consecutive batches while reducing the amount of
attention required from an operator and while producing a
consistently high quality of popped corn. This invention also
relates to an improved method for popping popcorn.
BACKGROUND OF THE INVENTION
[0003] Popcorn is mass-produced for sale at movies and other events
in commercial popcorn poppers which include an enclosed,
transparent cabinet containing a tiltable kettle suspended above a
catch area or platform. The kettle is heated and uncooked popcorn
kernels are placed therein to be cooked and popped. Once the
kernels are popped, the kettle is manually tilted and the popcorn
spills onto the platform to be scooped up, packaged and sold to
customers.
[0004] Conventionally, commercial popcorn poppers have been
manually operated and have required an operator's constant
attention for cooking the kernels and subsequently dumping the
popped popcorn. For example, an operator would load the kettle with
popping oil and unpopped corn kernels and then listen and watch for
the unpopped corn to pop. When the operator decided, somewhat
arbitrarily, that the corn was sufficiently popped, they would then
dump the kettle and spill the popcorn onto the serving platform.
Additional oil and corn would then be added for the next batch.
While such conventional popcorn poppers are generally effective in
mass-producing popcorn; the constant attention they require
prevents the operator from other important tasks, such as selling
the popcorn and other concession products, taking money and
generally servicing customers.
[0005] As may be appreciated, the multiple duties entrusted
concessionaire operators are not conducive to having them
constantly monitor a popcorn popper. If attention is diverted for
an extended length of time, the popcorn is susceptible to being
burned or overcooked. In addition to the waste of burned popcorn,
the aroma of the burned popcorn is not attractive to customers and
may actually discourage purchases . Furthermore, if the operator
inadvertently dumps the burned corn onto the platform, it will
contaminate the usable popcorn which has already been produced and
may render the entire batch inedible and thus unusable. Still
further, the results and mess from burned popcorn is not easy to
clean. The kettle is hot and must be allowed to cool before the
burned popcorn is removed and the kettle placed back in
service.
[0006] Additionally, the arbitrary nature of the dumping process
with conventional poppers makes them subject to messes associated
with premature dumping. For example, if the operator mistakenly
believes that the corn has been completely popped and the oil used
when indeed uncooked corn and oil remains in the kettle, tilting
the kettle will spill oil onto the serving platform and possibly
onto the counter. Such spills ruin and waste popcorn and create a
mess which must be cleaned, adding to the already numerous tasks of
a concessionaire.
[0007] Still further, too much oil may be added for a particular
cooking cycle, and even if the cooking cycle is completed, excess
oil might be left, again resulting in a mess upon dumping of the
batch. For example, one operator may load the uncooked corn and oil
for a batch, and another operator may subsequently and
inadvertently load more oil, beli ving it had not been added. The
excess oil does not burn off or cook and remains in the kettle. Not
only is a mess created upon dumping, but the excess oil may also
foul the batch of popcorn.
[0008] Another drawback of conventional popcorn poppers is the
inherent delays which will occur between cooked batches of popcorn.
When the popcorn has been cooked and dumped, the operator may begin
serving it to customers without replenishing the supply of corn and
oil and starting the next batch. Therefore, the next batch of
popcorn will not be produced until the operator consciously sets
aside time from his other activities to do so. Such delays
interrupt production rates and introduce inefficiencies into the
operation which reduce popcorn sales.
[0009] It is also desirable to pop popcorn consistently so that it
produces high quality consistent taste from batch to batch. The
vagaries of prior systems leave much to chance in this regard so
that batches of corn are undercooked, burned or the like and at the
least are inconsistent in taste.
[0010] Still another but related drawback to conventional popping
processes or mechanisms is that they sometimes provide inconsistent
or improper heating of the popcorn so that proper expansion of the
kernels upon popping is not achieved. Particularly, when the heat
is too high, the steam from the kernel is prematurely forced out
and the popped kernel is small. If the temperature is too low, the
kernels do not experience proper hull expansion and brittleness at
popping and the popped kernels are small. It will also be
appreciated that small popcorn kernels reduce the yield of popped
popcorn per unit of uncooked kernels, thus reducing the efficiency
of the popping apparatus and raising the cost of the operation.
[0011] While one aspect of the invention herein lends itself to
reduction of the vagaries of operational and processing
circumstances as noted above, it is also noted that it is important
for an operator to tend to the process at specific times, yet
remaining free to handle other chores while the popping process is
processing. For example, in many popping systems, it is desirable
and even necessary for an operator to tend to loading the kettle
with corn and oil for popping at an appropriate time in the cycle.
It is also desirable for an operator to monitor or to cause dumping
of popped corn from the kettle at a particular time to keep it from
burning. Yet it is also desirable both that the popping process
does not fully engage the operator doing the whole process and that
his attention to the process is positively obtained at such times
as loading and dumping.
[0012] In another aspect of the invention, it is recognized that in
the past, various improvements in popcorn have been made by popcorn
producers in the science and technology of the corn. These have
resulted in improved taste, improved kernel expansion rates and
more complete popping. Improvement in the popping machines or
equipment to produce better popped products have not generally kept
pace with the improvements in the corn. While there have been
certain improvements in poppers directed to better popped corn
products, such as in U.S. Pat. Nos. 5,743,172; 5,694,830 and
5,871,792, for example, there is still room for further equipment
and process improvement to improve the final popcorn product.
[0013] In particular and as referred to above, it should be
appreciated that popped popcorn should not be chewy, should have a
high expansion ratio from the unpopped kernel, and should have
about 12% to about 13% of the moisture of the raw, unpopped kernel.
Popcorn meeting these parameters is highly desirable from a taste
standpoint. Despite improvements in the corn kernels, however,
these final desirable parameters require improvements in popping
technology for consistency.
[0014] For example, if the moisture content of the kernel is
reduced too fast in the popping process, the kernel pops
prematurely, resulting in a small product. On the other hand, if
the moisture content of the kernel is reduced too slowly, the hull
first cracks, moisture leaks and the power of the remaining
moisture is not sufficient to produce the desired expansion of the
kernel for the final product. Thus the rate of application of heat
to the corn is a factor in producing the most desirable
popcorn.
[0015] In a typical popper, a covered heated popping kettle is
generally used. Heating elements are usually mounted on the
underside of the kettle and are controlled by a mechanical
thermometer between on/off status to heat and pop the corn therein.
In one instance, a thermocouple has been used. The elements are
disposed on a heat dissipation plate or surface on the kettle
bottom and have sufficient output to heat the kettle to a level in
excess of the ultimate temperature desired after popcorn kernels
and oil are loaded (which reduces kettle temperature from a control
or preset temperature). The elements produce such excess heat in
order to ensure that the appropriate popping temperature can be
reached is a desired time period.
[0016] In other words, when relatively colder corn and oil are
added to a heated kettle, the temperature drops, then climbs back
to a desired temperature so that the kernels are exposed to a
quantum of heat during a period necessary for popping. If the
elements were not so powerful, the desired heat may eventually be
attained but this could require an excessive duration of cooking
time.
[0017] The graph in FIG. 8 of U.S. Pat. No. 5,871,792 demonstrates
such a popping cycle. From a cold start with the kettle at an
ambient temperature, the heating elements are turned on to warm the
kettle. Its temperature rises to an "overshoot" level above a
"control" level of about 525.degree. F. The heating elements are
then cycled on and off upon sensing by a mechanical thermometer so
that kettle temperature cycles above and below the control
temperature.
[0018] When the unpopped kernels and oil are loaded into the
kettle, they are at ambient temperatures, much cooler than the
kettle's control temperature, and act as a heat sink, thus reducing
the kettle temperature, such as shown in the graph, down to about
325.degree., for example . The mechanical thermometer, for example,
eventually sensing this drop, causes the heating elements to
energize to raise the kettle temperature back up toward a
temperature where the corn is considered to have been popped and
can be dumped.
[0019] There are several areas in which this process could stand
further improvement as will now be discussed.
[0020] Applicant has determined that an ideal cooking time of from
about 3.0 minutes to about 3.5 minutes is preferred in order to
produce the best tasting popcorn with the highest expansion ratio
(largest size). Achievement of this ideal process requires close
control of the heat energy of the kettle. If the initial heat
energy of the kettle (i.e. considering kettle temperature and
kettle mass) and/or the ability to recover after the corn and oil
is loaded (i.e. considering temperature, mass and available wattage
of heating elements) is too low or too high, the cooking cycle will
be too slow or too fast respectively. When the cooking cycle is too
slow or too fast, the popcorn will be too small, chewy and will
have too many unpopped kernels.
[0021] Moreover, when the popping is first heated from a "cold
start", on initial turn on, its temperature rise may be rapid,
causing it to overshoot and reaching a higher temperature than
initially desired. While controllers such as that disclosed in the
aforementioned patents cited herein are useful in eliminating
excessive overshoot in subsequent cycles, they have not been so
advantageous for the initial cold start cycle or the first several
popping cycles thereafter before the cooking system reaches a
heating equilibrium. This can cause undesirable taste and quality
variations in the initial popped corn batches.
[0022] In order to fully understand the cooking process and as
background for the invention herein, it is helpful to articulate
certain definitions, functions and structure of popcorn poppers.
Generally, the kettle is as explained above and includes a covered
heated kettle provided with heating elements for heating a heat
dissipation plate or surface on the kettle bottom, and thus the
kettle.
[0023] Based on the kettle construction, its mass, the materials of
the kettle, etc. the power of the heat elements (watts) are
determined to permit the kettle to recover from the temperature
drop resulting from loading of the corn and oil. Then, one of the
significant remaining variables is the temperature of the kettle,
which determines the initial heat energy of the kettle. Thus, the
"control temperature" (Tcontrol) means a preselected temperature of
the cooking or popping surface of the kettle, which the controlling
method or apparatus allows the kettle to approach before it is shut
off in the first cycle from a cold start. The "load temperature"
(Tload) means the preferred temperature of the cook or popping
surface of the kettle at the time when corn kernels and oil is
loaded into the kettle before the temperature drop. The "dump
temperature" (Tdump) means the predetermined temperature of the
cook or popping surface of the kettle when the corn has popped and
the kettle is ready for dumping the popped corn. Typically in
current poppers, Tload is greater than Tdump by a small
percentage.
[0024] According to the invention, applicant has determined it is
desired to produce enough heat in the corn to cause it to be popped
when the kettle reaches a predetermined ump temperature at about
3.0 to 3.5 minutes after the kettle is loaded. Thus, according to
the invention, the kettle should be controlled in each cycl such
that a predet rmined Tdump is reached within the ideal cycle time
of about 3.0 minutes to about 3.5 minutes from the loading of
kernels and oil to dumping of popped corn. This appears to produce
the most consistently high quality, good tasting popcorn, the
process of the invention disclosed herein is directed to reaching a
predetermined and constant Tdump temperature for all situations.
The potential variations of cooking time based on varying Tload
temperature points are shown in the following graphs. These show
the relationship of varied Tload temperatures and the initial heat
energy of the kettle to the popping cycle in time.
[0025] FIG. 9 illustrates a situation where Tload is equal to
Tdump. FIG. 10 illustrates a situation where Tload is greater than
Tdump. FIG. 11 illustrates a situation where Tload is less than
Tdump.
[0026] From these graphical illustrations, the following
observations can be made:
[0027] First, the overall slopes of the curves are similar, just
shifted up or down. This is because all three graphs assume the
same heating elements and wattage, and the same kettle construction
and mass.
[0028] Secondly, the popcorn has completed popping at the same
Tdump temperature, independent of the Tload temperature of the
kettle when the corn is loaded. This observation will be described
later as one of the important concepts contemplated by the
invention.
[0029] Thirdly, the loading of corn and oil at different Tload
temperature extend or shorten respectively the duration of the
cycle until reaching Tdump. This inconsistency of Tload most
frequently occurs between the first or cold start cycle and the
subsequent cycles. If kernels and oil are added at that time, i.e.
a high Tload temperature, then the cycle time or duration may be
too short. If the kernels and oil are added at a lower Tload
temperature, too much before Tcontrol is reached, then the cycle
time is extended beyond that time duration desired.
[0030] It will also be appreciated that varying "lag" factors are
inherent in prior poppers, and that these lag factors prevent the
close control of kettle energy now desired and which is provided by
the invention herein.
[0031] Thus, if the Tcontrol temperature and the Tload temperature
are maintained as closely as possible according to the invention,
then the cycle duration can be more closely or accurately produced
within the desired cycle time of about 3.0 to about 3.5
minutes.
[0032] Given the importance of keeping the Tload temperature
substantially equal or as close to the Tdump temperature as
possible for the best quality popcorn according to this invention,
the challenge is to minimize the normal differences between heat
energy imparted to the corn for the first cold start cycle and for
the subsequent cycles. The differences can occur due to at least
the following circumstances:
[0033] a. The point where the temperature sensor is located is
separated from the cooking surface. This is related to the mass of
the materials between the temperature sensor located on one hand
and the cooking surface. The effect is a time and temperature lag
between what the cooking surface temperature actually is, and what
the remote temperature sensor and control "thinks" it is.
[0034] b. The surface where the heat elements are located is
separated from the cooking surface by the kettle components, which
also introduces a time and temperature lag. When the heat element
is turned on or off, there is a lag before the cooking surface
begins to react. There is also a small lag associated with the heat
element itself. Thus the mass of material between the heating
element and the actual cooking surface, as well as the rise time of
the heat element itself involves an inherent temperature and time
lag.
[0035] c. The traditional method of controlling temperature of a
popcorn kettle which is by use of a "mechanical" thermostat,
inaccuracy aside, or even a thermocouple with a set or
nonprogrammable control inherent introduces its own time lag
related to the mass and mechanical operation of such a sensor.
[0036] d. And perhaps most importantly, the fact that if the cold
start cycle is controlled the same way as subsequent cycles, the
initial Tload may be too low and the duration of that cycle, until
Tdump is reached could be too long.
[0037] The various factors described above are amplified by the
fact that the kettle's heat elements usually have far more power
than is necessary to simply hold the kettle at a Tcontrol or Tload
temperature. This is necessary to cook the popcorn in the required
time, i.e. to bring up the temperature of the corn for popping in a
desired time. With the lag times of many prior poppers, the net
effect is a large overshoot of preferred control temperature as the
kettle at least initially heats or an undershoot if the heat energy
is turned off too soon because of an excessive sensed rise rate. By
the time the mechanical thermostat or thermocouple reacts to turn
off the heat, the kettle surface temperature could exceed Tcontrol
by the overshoot. Also, even where a thermocouple is used, its own
heat equilibrium may not be obtained during the first or first
several cooking cycles and the accuracy and dose control of th
cooking process desired is not initially obtained. Conversely,
before the heat element turns on, the temperature will undershoot.
The chart of FIG. 12 demonstrates this operation.
[0038] The thermal transients in the system are believed to be one
of the be most significant of the factors generating this prior
profile in those systems using such sensors. As mentioned above,
there are two major problems with temperature sensors related to
the effects described.
[0039] First, overshoot from a cold start. The operator does not
know when to load the corn and oil from a cold start. If he puts
the kernels and oil in too early, the quality of the popped corn
will be poor. If he waits too long, he may "hit" the peak overshoot
temperature which will also cause poor quality popped corn and may
cause oil smoke.
[0040] When the PID controls heat rise from a cold start, the heat
energy may be turned off too soon, but the lack of heat equilibrium
results in less heat energy in the system and too long or time is
required for the kettle to recover to Tdump after its first
load.
[0041] Secondly, excessive popping cycle times due to low (and also
due to high) kettle temperatures are undesirable. The low condition
is obvious, but a high load temperature actually can cause lengthy
popping cycles up to 5 minutes. The kettle's temperature sensor
opens due to a high temperature. The overshoot permits the heat
energy of the kettle to increase further. If the corn and oil are
added at this time, the heat energy of the system falls quickly,
but the higher sensed surface heat from the overshoot "feeds" the
remote mechanical thermostat or thermocouple which keeps it from
closing. By the time the heat energy in the kettle mass between the
cooking surface and the remote sensor dissipates and the sensor
does close and the heat elements are turned on, the kettle cannot
recover to cook the popcorn close to the desired cycle time.
[0042] Accordingly, it is desired to produce a consistently higher
quality popcorn through improved apparatus and popping
processes.
[0043] Another objective of the invention has been to reduce
popping kettle temperature overshoots and undershoots as a function
of system parameters of prior popping systems.
[0044] Another objective of the invention has been to provide a
consistently higher quality popped corn by more closely controlling
the popping parameters of the corn poppers than in prior
systems.
[0045] A yet further objective has been to overcome the information
and problems generated by application of the control logic to both
cold start and subsequent popping cycles.
[0046] A yet further objective of the invention has been to provide
improved popped corn by insuring a consistent popping cycle within
the duration of about 3.0 to about 3.5 minutes independently of the
coincidence of the loading of kernel and oil with the temperature
(Tload) for all cycles of the popper.
[0047] It is another objective of the present invention to provide
improved apparatus and/or methods to pop popcorn continuously in
consecutive batches with minimal attention by an operator.
[0048] It is another objective to ensure that the popcorn is
consistently and properly cooked in each batch.
[0049] It is a further objective of the present invention to reduce
the burning of popcorn sometimes associated with conventional
machines and operator inattention.
[0050] It is also an objective of the invention to always provide
the proper amount of cooking oil and thus reduce the messes
associated with such burned popcorn or spilled, uncooked oil and
thereby allow an operator to focus upon customers and popcorn
sales.
[0051] It is a still further objective of the invention to reduce
the delays between fresh batches of popcorn attributable to lack of
attention by the operator.
[0052] It is a still further objective of the invention to increase
the production rate of consecutive batches of fresh popcorn to
thereby increase the sales from and the profitability of a
commercial popcorn popper.
[0053] Still further, it is an objective to provide the proper and
consistent heat to the kernels as they cook to ensure proper
popping conditions and to maximize the popcorn yield per unit of
kernels.
SUMMARY OF THE INVENTION
[0054] Addressing these objectives, the present invention comprises
a popcorn popper which may be left unattended to automatically cook
and dump popcorn once it has been loaded with the proper
ingredients, such as uncooked popcorn. Alternately, features of the
invention are also applicable to poppers with manually dumped
kettles. The proper, premeasured amount of oil pump is then added
by the oil pump system upon the initiation of a cooking cycle so
that the operator does not have to worry about measuring oil or
excess oil in the kettle. The popcorn popper of the invention is
responsive to kettle temperature conditions to automatically cook
popcorn kernels, subsequently dump the finished popcorn, and then
alert the operator to load more ingredients such as oil and
uncooked kernels, and start the next batch. In that way, all of the
batches of fresh popcorn are properly cooked at regular periods
with the proper amount of oil and heat, and the operator is left to
attend to other tasks.
[0055] According to the invention, popcorn is consistently cooked
by introducing an amount of popcorn and oil to a cooking system,
comprising a heated kettle, for a duration sufficient to heat the
corn and oil a predetermined amount, and then automatically dumping
popped popcorn after a sufficient amount of heat energy has been
absorbed by the corn and the oil to pop the corn. The application
of heat energy to the corn and oil is not monitored and controlled
by time, but rather by the heat conditions of the cooking system
for each batch. In this regard, a kettle is heated to a start
temperature and cycled about that temperature through a small
temperature range. When unpopped corn and oil are introduced, a
thermocouple on the kettle senses a temperature drop (cycle point)
and a cooking or popping cycle begins. The corn and oil absorb the
heat energy and are heated in the kettle until the kettle
temperature climbs back to a predetermined temperature (dump point)
indicating sufficient heat energy has been applied to the corn and
oil to pop the corn. At that point, the kettle is automatically
dumped.
[0056] Since the controller is temperature, rather then time
responsive, the operator is assured a consistent amount of heat is
always applied to the corn and oil for consistent popping. If the
kettle dump was controlled by time alone, and the environment
changed, such as a cabinet door being open, the cooking cycle might
time out before sufficient heat energy was applied to consistently
cook that batch of corn. Moreover, since the start temperature is
held within a narrow predetermined range, the oil and corn will not
be prematurely burned and the temperature gradients applied thereto
will be more consistent. Also, such a method accommodates at least
some variations in the amount of corn and oil introduced to the
kettle. If too little, the temperature drop will not be as great
and the rise to the predetermined dump temperatures takes a shorter
time, thus sufficient but less heat is introduced so this batch is
consistently popped. In a corresponding manner, larger amounts of
corn and oil will slow the climb of temperature to the dump point
insuring that sufficient heat is imparted to pop the corn
consistently with other batches.
[0057] To further ensure proper cooking by the invention, a
premeasured amount of oil is introduced to the kettle at the
beginning of a cooking cycle. The controller is coupled to an oil
pump system which is operably in fluid communication with the
kettle. Upon the kettle reaching the proper start temperature or
cooking temperature, the oil pump system and an oil pump switch are
enabled. The operator then actuates the oil pump switch to activate
the pump system and deliver a proper, premeasured amount of oil to
the kettle. The oil pump system and switch are disabled by the
controller if the kettle heat is not ON (no cooking cycle) or the
kettle is tilted from an upright position, such as to be cleaned.
Furthermore, in accordance with the principles of the present
invention, the oil pump system will only deliver one load of oil
per cooking cycle to prevent an oil overload or spilling of oil
when the cooked batch of popcorn is dumped. Therefore, the oil pump
switch may be actuated numerous times and only one load of oil will
be delivered per cooking cycle.
[0058] In an alternative embodiment of the invention, the
controller is operable to activate the oil pump system
automatically upon the initiation of a cooking cycle. To that end,
the controller provides an output signal to the oil pump system to
pump a premeasured amount of oil to the kettle at a predetermined
time in the cooking cycle. For example, the oil might be added when
the kettle has risen to a start temperature or might be added after
the popcorn has been added. If the oil pump system has a
mechanically adjusted timer mechanism for pumping a premeasured
amount, an output signal is provided by the controller to activate
the pump and pump oil into the kettle. If the oil pump system
includes a programmable timer mechanism, the controller is operable
to provide additional timer outputs to adjust the amount of time
that the pump will deliver oil when activated. In either case, a
premeasured and proper amount of oil is delivered to the kettle
each cooking cycle. The controller will not activate the pump
system until the kettle is hot and ready to cook and is
upright.
[0059] More specifically, the popper apparatus includes a kettle
which is coupled to a dumping motor and a heater which are
controlled by a controller which monitors the kettle temperature.
The controller includes a temperature sensor, such as a
thermocouple, which is operably connected to the kettle proximate
the heaters. By monitoring the temperature of the kettle, the
controller is operable to dump the kettle at the proper time and to
alert the operator when another batch of uncooked corn kernels
should be added to the kettle. Since the kettle temperature is
constantly monitored, and the dump cycle is automatically
controlled, the burning of popcorn is prevented. Furthermore, an
operator does not have to constantly monitor the procedure to
prevent such burning and can thus turn his attention to other
tasks. The popper begins a cooking or popping cycle when fresh
ingredients are added, and by alerting the operator at the end of
each popping cycle, the popper effectively reduces the delay
between batches to increase its productivity.
[0060] In a preferred embodiment of the invention, a programmable
logic controller (PLC) is coupled to a temperature controller
which, in turn, is coupled to a kettle thermocouple and to kettle
heaters. When the popper is turned ON and the kettle heat is turned
ON, the kettle is heated to an equilibrium start or cooking
temperature of, for example, approximately 525.degree. F. The
thermocouple and temperature controller preferably maintain the
desired 525.degree. F. kettle cooking temperature in a small cycled
range of +/-10.degree. F. When the kettle has reached the
equilibrium start temperature, the PLC activates indicators which
provide visual and audible indications that the kettle is ready to
make popcorn. The oil pump system and pump switch are enabled and
the operator actuates the oil pump switch to load the oil which is
pumped in by the oil pump, and also loads the uncooked popcorn
kernels.
[0061] Alternatively, the oil might be loaded by hand by the
operator. In still another alternative embodiment of the invention,
as discussed above, the PLC provides outputs directly to the oil
pump system to automatically pump oil to the kettle at the
initiation of a cooking cycle. The PLC is operably coupled to the
oil pump system to activate the pump for a predetermined amount of
time to ensure a premeasured amount of oil. A timer determines how
long the pump runs once activated to ensure the proper amount of
oil. The invention may incorporate an oil pump system having a
mechanically adjusted timer, such as a dial timer, or may
incorporate a system having a separate programmable timer. In the
latter case, the PLC is operable to provide separate output signals
to the programmable timer to set the pump time in addition to any
output signals to the pump for delivering oil for the amount of
time set by the timer.
[0062] The temperature controller senses the rapid drop in kettle
temperature associated with the absorption of heat from the kettle
by the corn and oil. When the temperature drop exceeds a set
amount, for example, 50.degree. F. below the equilibrium start
temperature, the PLC initiates a cooking cycle. The point of
initiation of the cooking cycle is designated the cycle temperature
or cycle point.
[0063] As the cooking cycle progresses, the PLC senses through the
temperature controller, that the kettle has dropped to a minimum
temperature below the cycle temperature. The minimum temperature
will depend upon the heat load added to the kettle. As the popcorn
pops, the temperature of the kettle begins to rise above the
minimum temperature. When the kettle temperature reaches a
predetermined dump temperature or dump point and the PLC that the
minimum temperature was previously reached and was preceded by the
cycle temperature, the popper indicates that the end of the cooking
cycle has occurred. Preferably, the predetermined kettle dump
temperature associated with the dump point for determining the end
of a cooking cycle is equal to the cycle temperature associated
with the start of the cooking cycle, i.e., approximately 50.degree.
F. below the equilibrium start temperature, for example. Upon
sensing the end of the cooking cycle at the dump point, the PLC
initiates a dump cycle and controllably energizes the dump motors
to tilt the kettle and dump the finished popcorn onto the surface
platform. The popcorn is immediately and automatically dumped at
the end of a proper cooking cycle, therefore preventing the popcorn
from burning. Furthermore, because of the unique temperature-driven
control of the popper, the popcorn is consistently and properly
cooked and may be served at the peak of freshness. The greater the
amount of corn and oil added, the longer the cooking cycle.
Conversely, the less the amount of corn and oil, the shorter the
cooking cycle.
[0064] Preferably, the motors are controlled to dump the kettle
twice to ensure complete dumping. After the first dump, the kettle
is only partially returned to a cooking or popping position. It is
then dumped again before fully returning to a popping position.
[0065] When the temperature controller indicates that the kettle
temperature is below the cooking cycle point and the machine is in
a cooking cycle, the PLC disables the dump motors and thus prevents
inadvertent dumping of the kettle contents.
[0066] When the popcorn has been dumped at the end of a cooking
cycle, the kettle will heat back up to the start cook point again,
and audible and visual indications are again initiated to remind a
busy operator to reload the kettle with fresh ingredients. This
prevents delays in between consecutive batches of popcorn and thus
increases the efficiency of the operator and the popcorn popper,
increasing production rates and profitability.
[0067] The present invention provides the proper application of
heat energy consistently to batches of corn kernels. In that way,
the kernels are heated to a sufficient temperature to provide
proper hull brittleness and expansion when the kernels pop but the
heat is not so high so as to force out the steam in the kernel
prematurely. Therefore, the invention achieves the desired corn
temperature and peak steam pressure for proper expansion. Expansion
rates of approximately 1:50 have been achieved with the invention
which is a significant improvement over some conventional devices
which achieve expansion rates of 1:44 or lower.
[0068] Therefore, the present invention automates the cooking and
dumping of popcorn and eliminates the need for constant operator
attention to the process. Production of consistently popped corn is
increased as is the profitability of the operation while incidents
of burned corn and inadvertently spilled oil or uncooked corn are
eliminated. Furthermore, the temperature control of the kettle
operation and the cooking cycle provides properly and consistently
cooked batches of popcorn.
[0069] An alternative embodiment of the invention contemplates the
use of a kettle-mounted thermocouple interconnected to an
electronic control system for operating the kettle's heating el
ments, and a different control logic for the first heat rise of the
kettle from a cold start condition. The thermocouple has negligible
mass, is located on the bottom of the kettle, and is connected to
the electronic control which will control voltage to the heat
elements, depending on the desired thermocouple open and close
temperatures. The overshoot and undershoot will thus be
significantly less due to the elimination of some lag due to the
use of remote mechanical thermostats in prior systems. Moreover,
the control system is programmed to energize and deenergize the
heating elements in response to the sensing conditions of the
thermocouple at temperatures which lead to the desired cook surface
temperatures as a function of kettle mass and heating element lags
in both directions (i.e. temperature rises and drops). Thus, the
thermocouple sensed temperatures are handled by the control system
as a function of the desired temperatures taking into consideration
kettle mass and other lag factors so the heat energy that the corn
kernels experience is closely controlled to predetermined
levels.
[0070] The cold start problems noted above are prevented by
directly controlling the application of heat to the kettle on the
start up, outside of the normal control loop. In particular, heat
energy input is not retarded or controlled so quickly as it is
later when the structure has reached heat equilibrium. Thus, the
program for normal operation is varied for the first cycle to
insure that batch is consistently popped within the desired time
frame as subsequent batches. The system then returns to normal
control mode. Thus, the control system recognizes the cold start
situation for the first cycle.
[0071] In other words, on cold start, the control system logic for
remaining cycles is not applied to the kettle heat. Instead, the
temperature rise is allowed to continue to a point beyond where it
would be allowed to rise for subsequent cycles when the kettle has
reached equilibrium. In this manner, the kettle is allowed to heat
to a higher point, recognizing that total heat in the system is
less than it will be later. Thus, when corn and oil are added and
the temperature drops, the higher start temperature supports the
kettle's recovery to a Tdump temperature in a similar time frame to
that of subsequent cycles. Without the "override" of the control
logic for the first cold start cycle, the heat energy would be
retarded sooner and corn loading would drop the colder kettle to a
much lower temperature than desired, from where it could take an
excessive time to recover.
[0072] The chart of FIG. 13 illustrates the contrast between the
invention and the prior systems.
[0073] It will be appreciated that Tdump, according to the
invention, is constant and independent of Tload. According to the
invention, Tdump is independent of many other variables,
including:
[0074] Low voltage, which reduces the power of the heat
elements.
[0075] Variations in the amount of corn and/or oil that are added
to the kettle.
[0076] Variations in the kettle components: heat elements, etc.
[0077] The system is thus controlled that, given the same Tdump,
temperature popping time will vary only within the desired cycle
time of about 3.0 to about 3.5 minutes for every cycle.
[0078] In another aspect of the invention, and even where an
automatic dump mode is or is not selected, or in other poppers
where there is no automatic dump mode, the electronic control
system is operable to sound audible or visual alarms, such as a
buzzer or flashing light, to alert the operator to dump the popcorn
at the correct time. Also, such alarms are programmed to alert the
operator to do one of the following three things according to the
invention:
[0079] 1. From a cold start, an alarm signals when the operator
should first add the corn and oil.
[0080] 2. When popping, an alarm signals when to dump the popcorn.
The larger benefit is the fact that it alerts the operator, who is
busy or distracted, to dump the popcorn before it burns. Burned
popcorn is a significant problem in a busy theatre, for
example.
[0081] 3. When the operator is done popping corn, an alarm reminds
him to turn off the master power to the kettle heat to save
energy.
[0082] The invention also contemplates the process of producing
popcorn by popping corn kernels in oil for a time period of about
3.0 to about 3.5 minutes from loading kernels and oil into a
popping kettle to dumping popped corn therefrom. That is, the
invention contemplates the popping of popcorn in a time duration
from loading kernals and oil into a kettle to dumping popped corn
therefrom in a time period of from about 3.0 to abut 3.5 minutes
and after a set Tdump temperature is reached, regardless of typical
variations in the quality of corn and oil added by operator error
and variations in the Tload temperature between cold start and
later cycles.
[0083] According to the invention, a preset Tcontrol temperature
thus defines a maximum Tload for the first cold start cycle and
thereafter for subsequent cycles, function as a safety or cutoff
temperature, causing a system shutdown when reached for review and
safety considerations.
[0084] Advantages of the invention are numerous. It produces a high
quality, consistent, popped product. It eliminates lag times of the
prior temperature sensors used in prior popping systems. It reduces
temperature overshoots and undershoots from a desired control
temperature. It assures a predetermined cycle time within a set
range and with a consistent product. It produces a high quality
consistent product independent of variables inherent in prior
systems which limit product consistency. It provides a close
control of popping parameters, including close control of kettle
energy to produce a non-consistently high quality product.
[0085] It will also be appreciated that the invention in its
alternate embodiment can be used in controlling only the initial
cold start cycle differently from the subsequent cycles or the
first several cycles from a cold start in the same way, differently
from remaining cycles when heat equilibrium is reached.
[0086] These and other objectives and advantages will become
readily apparent from the following detailed description of
preferred and alternative embodiments of the invention, and from
the drawings in which:
BRIEF DESCRIPTION OF THE DRAWING
[0087] The accompanying drawings, which are incorporated in and
constitute a part of this specification, illustrate embodiments of
the invention and, together with a general description of the
invention given above, and the detailed description of the
embodiments given below, serve to explain the principles of the
invention.
[0088] FIG. 1 is a perspective view of a popcorn popper apparatus
in accordance with the principles of the invention;
[0089] FIG. 1A is a perspective view of the top of the popcorn
popper of FIG. 1;
[0090] FIG. 1B is perspective view of the popcorn popper of FIG. 1
illustrating the oil pump system.
[0091] FIG. 2 is a cross-sectional view of a popcorn popping kettle
as seen on line 2-2 of FIG. 1;
[0092] FIG. 3 is a cross-section taken along lines 3-3 of FIG.
2;
[0093] FIG. 4 is a perspective-view of the kettle of the popcorn
popper of FIG. 1;
[0094] FIG. 5 is a perspective view of the kettle of FIG. 4 removed
from its housing for cleaning;
[0095] FIG. 6 is a diagrammatic view of the electrical components
of the popcorn popper of FIG. 1;
[0096] FIG. 7 is an operation flowchart of the popcorn popper
apparatus of the invention;
[0097] FIG. 8 is a temperature graph versus time of the kettle
during a popcorn cooking cycle.
[0098] FIG. 9 is a graphical illustration of a popping process
where Tload temperature is equal to a set Tdump temperature and
shows the effect on time;
[0099] FIG. 10 is a graphical illustration of a popping process
where Tload temperature is greater than the set Tdump temperature
and shows the effect on time;
[0100] FIG. 11 is a graphical illustration of a popping process
where Tload temperature is less than the set Tdump temperature and
shows the effects on time;
[0101] FIG. 12 is a graphical illustration showing a popping
process of the prior art;
[0102] FIG. 13 is a graphical illustration showing kettle surface
temperature cycles of a popping process of one embodiment of the
invention compared to those of a prior popping system;
[0103] FIG. 14 is a diagrammatic view of the electrical components
of a popcorn popper similar to FIG. 6 but according to an alternate
embodiment of the invention; and
[0104] FIG. 15 is an operational flow chart similar to FIG. 7 but
illustrating an alternative embodiment of the invention.
[0105] FIG. 16 is a temperature graph versus time of the kettle
during popcorn cooking cycles for another embodiment of the
invention.
DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS
[0106] Turning now to the drawings, there is shown in FIG. 1 an
automated corn popper 10 according to the invention. It will be
appreciated that the popper is operable to cook or to pop popcorn
and is particularly useful for cooking consecutive batches of
popcorn for sale for use by concessionaires at movie theaters,
sport events, fairs and the like.
[0107] The corn popper 10 includes a cabinet having transparent
walls including two sidewalls 11, 12, a rear wall 13, front wall
14, and a service platform 17 for catching popcorn. Front wall 14
includes two doors 15, 16, which can be opened to gain access, both
to the popped corn on the platform 17 of the cabinet and to the
kettle 18. Sidewalls 11, 12 and rear wall 13, as well as the front
wall 14 including doors 15, 16, are all made preferably of
transparent glass or plastic material so that the interior of the
cabinet can be viewed from the exterior. The cabinet may also
include various operating switches and light indicators on an
operating panel 25 for turning ON kettle heat, the dump motor, a
warmer (not shown) under platform 17 and lights inside the cabinet
as well as turning ON the heaters and pumps of an oil pump system
(see in FIG. 1B) for providing cooking oil for the operation. The
lights may indicate that one or more of these systems are ON.
Various of these systems will now be described in greater detail in
accordance with the principles of the present invention.
[0108] The cabinet of popper 10 also preferably includes an oil
pump system 36 which would rest below the platform in the cabinet
(see FIG. 1B). The oil pump system 36 provides oil to the kettle
during a cooking cycle and might be one of various different
systems. For example, Gold Medal Products Co. of Cincinnati, Ohio,
which is the owner/assignee of the present patent application,
markets the Model 2114 Accumeter Bucket Pump for pumping popcorn
oil. Another system, Model 2257 Rack Oil Delivery System, is also
available from Gold Medal Products and is discussed in U.S. patent
application Ser. No. 08/541,469 entitled "Oil Supply for Popcorn
Poppers", which application is incorporated herein by reference in
its entirety. While those oil systems manufactured by Gold Medal
Products Co. are preferable, the present invention might be
utilized with other systems as well.
[0109] The popping kettle 18 is of any suitable variety having a
heater (not shown in FIG. 1) interconnected by a control line 19 to
a power plug 20 mounted inside on the top 21 of the cabinet. It
will be appreciated that the kettle 18 is tiltable about a tilt
axis 22 (FIG. 2) and is provided with covers 23 and 24 which are
pivoted on the kettle 18. When the corn is popped, it pushes these
covers open and falls out the sides of the kettle onto platform 17.
Moreover, it will be appreciated that the cover 23 is located over
a so-called "dump section" or side of the kettle 18. When the
kettle is tilted, this cover pivots open to facilitate dumping of
popcorn onto platform 17.
[0110] Positioned between covers 23, 24 is an oil funnel 29 which
has a flared funnel mouth 30. When the kettle 18 is upright as
shown in FIG. 1, the funnel 29 aligns with an oil outlet 37 which
is coupled via a delivery tube 39 to oil pump system 36. Oil is
pumped up by system 36 to drain into funnel tube 29 and kettle 18
for use during a cooking cycle as discussed in greater detail
hereinbelow.
[0111] The kettle 18 includes an internal agitator, stir blade or
rotor 38 (FIG. 3) driven by a rotor drive shaft 26 having an upper
pilot end 27 and a driven gear 28 thereon. Referring to FIG. 4,
when the kettle is in a cooking position as shown in FIG. 1, the
upper pilot end 27 of the rotor drive shaft 26 is located in a
socket 31 defined in a rotor drive housing 32 adjacent a drive
shaft 33 and a drive gear 34. The drive gear 34 intermeshes with
the driven gear 28 on the upper pilot end 27 of the rotor drive
shaft 26 to drive the rotor within the kettle to promote popping.
Directly above socket 31 in drive housing 32 is a position sensor
35 which determines that shaft 26 is seated in socket 31 and kettle
18 is in a cooking position. The sensor 35 promotes more accurate
positioning of the kettle after it is tilted as discussed in
greater detail below. The stir blade and shaft 26 are rotated by
stir motor 68 which is activated by an appropriate operating switch
on the panel 25 or by the controller of the invention as discussed
below.
[0112] Referring again to FIG. 3, the blade 38 of the invention is
weighted to prevent popcorn from being trapped against the blade
during a dump cycle. As discussed further hereinbelow, the kettle
18 is tilted or dumped during a cycle to dump out the cooked
popcorn. To prevent hindrance of the popcorn by blade 38, the blade
is weighted on one side with an appropriate weight element 47 which
causes the blade to rotate to a downward or generally vertical
position during a kettle dump cycle. The blade 38 is then out of
the way of the dumped popcorn so that popcorn falls freely from the
kettle.
[0113] The kettle is mounted in the cabinet of the popper 10 by way
of a drive housing 40 and a spring-like hanger bracket 41. The
spring-like hanger bracket 41 includes an L-shaped bracket having a
foot 42 for interconnection to the top 21 of the cabinet. The
depending flat spring leg 43 is provided with an aperture or slot
44, as will be further described.
[0114] On the other side of the kettle, the drive housing 40 houses
the drive shaft 48, which is provided with a worm gear 49 on the
bottom end thereof. A drive stub shaft 50 is provided with a gear
51 for intermeshing with the worm gear 49. The opposite end of the
drive stub shaft 50 is provided with a drive stub 52 disposed in a
socket 53 of the drive housing 40. The upper end of the drive
housing 40 is provided with a mounting foot 54 for securing the
drive housing 40 to the top 21 of the cabinet of the popper 10. In
addition, it will be appreciated that the drive shaft 48 can be a
one-piece drive shaft or it can be coupled through a coupling 55 to
the depending drive shaft 56 of a dump motor 58 (FIGS. 1 and 1A).
Drive shaft 48 is journaled in a blind bore 45 located in an
externally threaded bushing 46 in the bottom of housing 40 (FIG.
3). This prevents lubricants from leaking into the popped pop
corn.
[0115] The kettle 18 is provided with a drive boss 60 and a hanger
boss 61. The drive boss 60 is provided with a slot 62 for receiving
the drive stub 52, supported by the drive housing 40. The hanger
boss 61 extends from the other side of the kettle with respect to
the drive boss 60 and is provided with a groove 63 for receiving
the depending leg 43 of the hanger bracket 41. In this regard, the
groove 63 fits within a slot or aperture 44 of the hanger bracket
41 so that the kettle can be rotated about the pivot axis 22. At
the other drive side of the kettle, the drive boss 60 resides in
the socket 53, defined by the drive housing 40, so that the drive
boss 60 can rotate in that socket. It will be appreciated that the
socket has an opening 64 for accommodating radial movement of the
drive boss 60 with respect to the socket and to the drive stub 52
when the drive stub 52 and the recess 62 in the drive boss 60 are
aligned with the opening 64 to permit the drive boss to be moved
outwardly of the socket.
[0116] Alternatively, the kettle could be supported in a
cantilevered fashion only by the drive boss or other supporting
apparatus as will be appreciated.
[0117] Turning now momentarily to FIG. 1A, there is shown a
perspective view of the top of the popper 10 showing various
components of the popper mounted outside the cabinet on the top 21
thereof including parts of the kettle operating system. The kettle
operating system as it is termed herein includes the kettle heaters
(not shown) and the kettle dump motor 58 as well as the control
components which operate the popper in accordance with the
principles of the invention.
[0118] As shown in FIG. 1A, the dump motor 58 is mounted on the top
21, such that drive shaft 56 extends downwardly through the top 21
and into the drive housing 40 (FIG. 3). A rotor drive motor or stir
motor 68 is also positioned on the top 21 so that its drive shaft
33 extends downwardly through the top 21 and through the housing 32
for interconnection with the drive gear 34. A buzzer 70 is
positioned preferably on the top 21 as shown, as well as a cabinet
light 75, a ventilator 76 and various support circuitry for the
components, including a Programmable Logic Controller (PLC) 77, a
temperature controller 82, and a solid state relay 86 to the kettle
heaters.
[0119] The control components for the control system of the
invention comprise a Programmable Logic Controller, or PLC, such as
a PLC made by Omron Electronics, Inc., One East Commerce Drive,
Schaumburg, Ill. 60173, under the Model No. C20R. PLC 77 is
connected to dump motor 58 through an UP relay 78 and a DOWN relay
79. The PLC is also connected to the audible buzzer 70 and to light
71 for audibly and visually notifying an operator when the kettle
18 is ready to receive another batch of popcorn, oil, salt and
other ingredients. The visual indicator light 71, which may be
positioned on control panel 25, flashes to visually alert an
operator that the kettle is ready for another batch of ingredients
simultaneous with the buzzing of buzzer 70. The visual indicator
light 71 will provide a visual indication to an operator and is
particularly helpful in the case of multiple machines in an area
where it may be difficult to determine which one is buzzing. The
PLC 77 provides output signals to the dump motor relays 78 and 79
to tilt the kettle and dump the popcorn cooked therein at the
cessation of a cooking cycle. Output signals from the PLC 77 to the
buzzer 70 and light 71 produce an audible signal and a visual
signal which ensure consecutive batches of fresh popcorn without
delays between batches as are normally associated with conventional
popcorn machines.
[0120] The present invention is operable to monitor the temperature
of the kettle to automatically alert the operator to load
ingredients to automatically begin a cooking cycle when ingredients
are loaded, and to end the cooking cycle and automatically initiate
a dump cycle to empty the popcorn and again alert the operator to
load more ingredients for the next batch. The invention monitors
the kettle temperature and determines at certain temperature
checkpoints which operations are to be automatically executed.
Therefore, the popper of the invention may be loaded with corn
and/or oil and then ignored until the next ingredients load to free
the operator to handle other tasks. To that end, the control system
of the invention further comprises a temperature controller 82 to
control the heating of kettle 18 and to provide input signals to
the PLC 77 for initiating a popcorn cooking cycle and subsequently
for controlling dump motor 58 to dump finished popcorn from the
kettle after a cooking cycle is complete. The temperatur controller
82 has an output line 84 which is operably coupled to a solid state
relay 86 connected to kettle heater 88. To provide a temperature
input to the PLC, a thermocouple 90 is operatively connected to
kettle 18 close to kettle heater 88 to monitor the temperature of
the kettle. An output signal on line 92 from the thermocouple is
input into the temperature controller 82. Through thermocouple 90
and line 92, the temperature controller 82 monitors the temperature
of kettle 18 and turns power to the heater 88 ON and OFF through
solid state relay 86 to maintain the temperature at a predetermined
start temperature or equilibrium temperature. Preferably, the start
temperature is approximately 500.degree. F. to 525.degree. F.,
although it will be appreciated by one of ordinary skill in the art
that such a temperature might be varied up or down for a particular
size kettle or other variable cooking conditions.
[0121] The temperature controller 82 communicates on line 94
directly with the PLC 77. Line 94 is a low temperature alarm line
which is utilized to set the beginning of the cooking cycle and to
initiate a kettle dump at the end of the cooking cycle. As
described further hereinbelow, temperature controller 82 sends an
input signal on line 94 to the PLC 77 when thermocouple 90
indicates that the kettle temperature has dropped below a
predetermined temperature or low alarm temperature, such as when
uncooked popcorn kernels and oil are poured into the kettle 18, and
through thermal loading, cause a rapid decrease in the kettle
temperature. The falling temperature passing through the low alarm
temperature point 149 indicates that a cooking cycle has been
started (See FIG. 8). As may be appreciated, as the popcorn in
kettle 18 cooks, the thermal load is reduced and the temperature of
kettle 18 begins to rise again. The kettle temperature will again
pass through the low alarm 150 temperature point, except this time
as a rising temperature rather than a falling temperature, the
rising temperature passing through the alarm point indicates the
end of the cooking cycle (See FIG. 8). At such a time, a signal is
sent on line 94 to the PLC 77 to initiate a kettle dump procedure
to dump the cooked popcorn onto service platform 17 as discussed
below. While the low alarm temperature may be variably adjusted in
temperature controller 82, it is preferably set to be approximately
50.degree. F. to 75.degree. F. below the start temperature
referenced above, e.g., it may be set to be approximately around
425.degree.-500.degree. F., depending upon the preferred start
temperature. The temperature point indicating the temperature 149
as it first falls through the low alarm temperature when uncooked
popcorn is added to the kettle is designated the cycle temperature
or cycle point as it indicates to the PLC the beginning of an
official cooking cycle. A cooking cycle is not begun until the
kettle drops below the cycle temperature 149 to prevent false
cycles which might occur as the empty kettle fluctuates around the
start temperature (see FIG. 8). That is, the substantial drop from
the start temperature will indicate that corn and oil have been
added to the kettle. The subsequent point 150 wherein the
temperature increases back up to the low alarm temperature after
the popcorn is cooked and popped is considered the dump point or
dump temperature because the PLC initiates a kettle tilt to dump
the popcorn at that temperature. Preferably, the cycle temperature
149 and 150 and dump temperature are approximately the same (see
FIG. 8), e.g., approximately 475.degree. F. However, it may be
appreciated that the temperatures might also be offset from each
other. Both the cycle temperature and dump temperature are below
the start temperature point.
[0122] In order to ensure stable heating of kettle 18, the
temperature controller 82 will preferably cycle solid state relay
86 and heater 88 ON and OFF numerous times as the kettle
temperature closely approaches the equilibrium start temperature.
This reduces substantial conditions beyond levels 142 and 152 of
the kettle temperature which might occur should the heater be
turned OFF only at the time that the kettle reaches the start
temperature due to thermal transients in the system. A suitable
temperature controller for use with the invention is the Model 935
Proportional Integral Derivative or PID, programmable temperature
controller available from Watlow, 1241 Bundy Blvd., P.O. Box 5580,
Winona, Minn. 55987-5580. The Model 935 temperature controller 82
is capable of monitoring when the kettle temperature is getting
close to the equilibrium start temperature and operably slowing
down the heating process as that start temperature is approached.
The Model 935 temperature controller also has an alarm silence
feature which prevents kettle dumping when the kettle is heating
up:upon initial powerup. For example, as discussed above,
temperature controller 82 monitors a rising temperature which
reaches the predetermined low alarm temperature in order to
indicate the end of a cooking cycle and to control the dump motor
58 to dump the kettle. As may be appreciated, a rising temperature
passing through the low alarm temperature is a scenario which will
occur upon initial powerup as the kettle heats from a cold state to
an equilibrium start temperature. In order to prevent a kettle dump
at initial powerup, temperature controller 82 has a start override
feature to ignore the first rising pass 151 through the
predetermined low alarm temperature (See FIG. 8).
[0123] As the temperature controller 82 monitors the kettle
temperature, it controls the operation of the heater 88 through
solid state relay 86. The present invention alerts an operator when
the kettle is ready to cook, and to indicate to the PLC 77 when
kettle temperature has reached the equilibrium start temperature, a
slave relay 96 is coupled to the output of relay 86 and provides an
input to the PLC 77 on line 93. When the solid state relay 86 is
closed to provide power to the heaters 88 to heat kettle 18, a 24V
signal is delivered to PLC 77 through slave relay 96. When the
solid state relay 86 closes and turns power to heater 88 OFF and
remains OFF, indicating that the kettle has reached start
temperature, (e.g., 525.degree. F.) the slave relay 96 stops the
signal to the PLC 77 and the PLC, in response, provides an output
to buzzer 70 and light 71 to produce an audible and visual
indication and alert the operator that the kettle is ready to cook
popcorn. With consecutive batches of popcorn, buzzer 70 and light
71 will again be energized to provide an audible and visual
indication indicating that the popcorn has been cooked and dumped
and the kettle is ready for another batch of popcorn kernels. In
that way, consecutive batches are made without delay.
[0124] The PLC 77 is also coupled to the kettle heat switch 80 to
monitor when the kettle heat to popcorn popper 10 is turned ON and
OFF. When power to the kettle heater 88 is turned OFF, the PLC 77
will internally reset a status bit. Thus, the PLC is not fooled
into initiating a kettle dump when the power is turned OFF and then
ON again, and in that way, the PLC 77 further prevents inadvertent
dumping. For example, when the power and the heat to the kettle are
turned ON by turning on switch 80 to deliver power to relay 86, the
PLC 77 monitors the kettle temperature through temperature
controller 82. If the heat 80 is then turned OFF, kettle
temperature would drop, simulating thermal loading of the kettle
with fresh popcorn and oil when indeed no popcorn or oil is loaded.
If the kettle heat is then again turned ON, the PLC 77 may note the
rising temperature passing through the low alarm temperature point
and thus may believe that a batch of popcorn has been cooked and
that it is time to dump the kettle. By resetting the PLC 77 status
bit upon an interruption of power to the heater 88, such a scenario
is avoided. A high limit switch 98 is coupled to the kettle heater
88 to cut off the power to the heater if the kettle temperature
exceeds a set upper limit, such as if the solid state relay 86
stays open or the temperature controller malfunctions.
[0125] The stir motor 68 turns a blade (not shown) during the
cooking of the popcorn. In one version of the invention, stir motor
68 is turned on by a switch at the operating panel 25 and stays on.
Alternatively, power to the stir motor is routed through PLC 77 and
is controlled by PLC 77 as noted by line 73. PLC 77 operates the
stir motor 68 so that the blade stirs automatically only during a
cooking cycle and stops when the cooling cycle is complete
independent of operator attention.
[0126] The oil for cooking the popcorn may be delivered either by
hand, by the operator actuating a switch on the operating panel 25
which is coupled to pump system 36, or alternatively may be handled
automatically through PLC 77 to automatically deliver oil at the
initiation of a cooking cycle. Oil pump system 36 preferably
includes a reservoir 101, a control housing 103, and a pump 104 to
pump oil from the reservoir. The pump system 36 will also usually
include a heater (not shown) for heating congealed oil to a liquid
state before pumping. The heater may be operably coupled to the
control panel so that the oil may be properly heated for being
pumped to kettle 18.
[0127] In one embodiment of the invention, the oil pump 104 is
operably coupled to an oil pump switch 106 which is located at the
operating panel 25. When the kettle heat switch 80 is ON and the
kettle heats to the start temperature, oil will be needed for a
cooking cycle. In accordance with the principles of the invention,
oil pump switch 106 will be effectively disabled until all
conditions are proper for a cooking cycle. Switch 106 is operably
coupled to PLC 77 as indicated by line 111 and the PLC 77 is
operably coupled to oil pump 104 as indicated by line 113. PLC 77
disables switch 106 until the kettle heat switch 80 is ON, as
indicated by control line 11 5 between switch 80 and PLC 77, until
kettle 18 is upright, as indicated by proximity switch 35 coupled
to PLC 77, and until kettle 18 is properly heated as indicated by
the thermocouple 90 and controller 82. This prevents oil from being
pumped to funnel 29 from reservoir 101 until the kettle is hot and
in the proper position.
[0128] Upon enablement of the oil pump switch 106, the operator may
engage the switch to deliver a premeasured amount of oil from
reservoir 101. Generally, pump 104 will be controlled by a timer
129 (see FIG. 6) which may be adjusted by a mechanically adjusted
dial 117. In that way, the pump 104 will pump oil to kettle 18 for
a predetermined amount of time to deliver the proper premeasured
amount of oil. When the timer 129 times out, the pump 104 stops.
Upon delivery of the oil, PLC 77 will disable switch 106 so that no
more oil may be added until the next cooking cycle. In that way
excess, uncooked oil is generally not present in the kettle, thus
preventing any spills or messes. Pump 104 is coupled to line 39 for
oil delivery.
[0129] FIG. 1B illustrates the oil pumping system which is the
subject of U.S. patent application Ser. No. 08/541,469 and greater
detail about the operation of the system is given therein. Pump
system 36 is usually referred to as a bag-in-box system and
includes a container 118 on top of control housing 103 which holds
a flexible bag of oil 121. An oil tube 123 connects bag 121 and
reservoir 101. Alternatively, an oil bucket or pail system, such as
the Model 2114 Accumeter Bucket Pump (not shown) may be used.
[0130] In an alternative embodiment of the invention, the PLC 77 is
operably coupled to pump 104 and timer 129 by control lines 131, so
that delivery of oil is automatic. When the kettle 18 heats up, and
is in the proper upright position as discussed hereinabove, the PLC
77 will automatically actuate pump 104, instead of enabling switch
106 and requiring the operator to actuate the switch 106.
Therefore, oil is delivered automatically at the beginning of a
cooking cycle. The operator then only has to add popcorn kernels,
as the cooking cycle begins. Timer 129 will control how long pump
104 runs once it is actuated to deliver the proper amount of oil.
Timer 129 may be a programmable timer which is set by the PLC 77
control lines 131 and may be programmed for certain, preselected
amounts of oil for a batch. That is, the PLC 77 controls the timer
129 as opposed to a mechanical mechanism such as dial 117. Once the
timer 129 times out, pump 104 stops and will not be reactuated
until the next cooking cycle. As with the previous scenario, if the
kettle heat switch 80 is OFF, no oil is added to the kettle.
[0131] It will be understood that various combinations of oil
loading steps might be utilized in accordance with the principles
of the invention. For example, the oil pump 104 may require switch
actuation while the timer 129 is automatically programmed by PLC
77. In another version, the pump 104 may be automatically actuated
by PLC 77 while timer 129 is manually set by a dial 117 or other
mechanical device. The oil system 36 will generally include a
preheater (not shown) for liquefying the oil prior to pumping. The
preheater may be actuated at the control panel 25 or directly at
the control housing 103 of oil system 36.
[0132] As the popcorn and oil are cooked during the cooking cycle
and the kettle temperature begins to rise, it rises through the low
alarm temperature 150 point or dump point as discussed above. A
kettle temperature rise through the low alarm point or dump point
which was preceded by a cycle point indicates the end of a cooking
cycle and the invention is then operable to initiate a dump cycle.
At the initiation of the dump cycle, the PLC 77 actuates the DOWN
relay 79 to direct the dump motor 58 to rotate the kettle
downwardly and thus dump the contents. The down relay is actuated
for a predetermined period of time and then the relay is
deactuated. Assuming that the cooking position of the kettle as
illustrated in FIG. 1 is 0.degree., the kettle is rotated
approximately 180.degree. for the first dump to dump the popcorn
contents therefrom. That is, the kettle is turned upside down.
Subsequently, the PLC 77 actuates the UP relay 78 to energize dump
motor 58 and move the kettle 18 toward the cooking position.
However, the UP relay is only actuated to return the kettle
partially to its cooking position and in fact is preferably
energized for a time period sufficient to move the kettle to an
approximately 60.degree. angle between the 0.degree. cooking
position and the dump 180.degree. position. This partial return is
obvious to the operator and prevents him from believing the kettle
is in the cooking position. Therefore, the operator is not misled
into prematurely loading popcorn and oil into the kettle.
[0133] After the partial return toward the cooking position, the
DOWN relay 79 is again actuated to make the dump motor 58 rotate
the kettle downwardly to 180.degree. to again dump the popcorn
contents. The two-stage dump cycle of the present invention
provides proper and complete dumping of all the contents from
kettle 18 so that little or no popcorn remains in the kettle to be
burned during the next cooking cycle. After the second dump, the UP
relay 78 is actuated to energize dump motor 58 to return the kettle
to the upright cooking position. Thus, the kettle 18 is rotated to
a full dump position, partially returned, rotated to a full dump
position again, and then fully returned to the cooking position for
another cooking cycle.
[0134] Referring again to FIG. 4, when kettle 18 is returned to the
cooking position, the upper pilot end 27 of drive shaft 26 engages
socket 31, and in doing so will actuate the proximity switch 35.
Proximity switch 35 is preferably a metal detecting proximity
switch which indicates the presence of the shaft end 27. Upon
sensing the shaft end 27, the proximity switch 35 provides an input
to PLC 77 which then simultaneously actuates both the UP and DOWN
relays 78, 79 to lock the dump motor 58 and provide a secure stop
when the kettle is returned to the cooking cycle. Proximity switch
35 provides secure placement of the kettle in the cooking position
and allows rapid return of the kettle to that position without
slowing the motor down as the kettle approaches. The present
invention thereby prevents overshoot of the shaft end 27 and socket
31 and also ensures that the gears 28 and 34 are properly seated
for the next cooking cycle. The proximity switch also ensures that
oil can be added to the kettle 18 only when the kettle is
upright.
[0135] Upon the return of the kettle 18 to the cooking position
with the kettle heated back up to the start position, PLC 77 again
actuates buzzer 70 to provide an audible indication to the operator
that another batch of ingredients should be added to the kettle. In
that way, consecutive batches of popcorn are made with very little
delay between the batches. Thus, the productivity of the operator
and the popper 10 and the profitability of the entire operation, is
increased. PLC 77 operates to actuate buzzer 70 at ten second
intervals until new ingredients are loaded into the kettle 18. In
that way, the operator cannot ignore the popper 10 of the invention
as it will continue to alert him until another batch of ingredients
is loaded. If the buzzer is ignored for ten minutes, it will begin
to sound continuously.
[0136] Kettle 18 may also be removed and cleaned as d scribed in
the parent application entitled AUTOMATED CORN POPPER referenced
above. To that end, the PLC 77 is operably coupled to a clean
switch 99. When the clean switch is actuated, PLC 77 is operable to
actuate the DOWN relay 79 and dump motor 58 to tilt the kettle 18
to a position between the cooking position and the full dumping
position. In this intermediate position, the plane of the drive
stub 52 is aligned with the opening 64 and the socket 53, thereby
permitting the drive bar 60 of the kettle to be lifted out of the
socket, cleaned, and then subsequently replaced for further popcorn
cooking as illustrated in FIG. 5.
[0137] Further understanding of the present invention may be
obtained by a discussion of the operation of the invention and
particularly to operation of PLC 77. An operational flowchart is
illustrated in FIG. 6.
[0138] Prior to beginning a cooking cycle or in order to clean the
kettle, the heat switch 80 should be OFF (block 95). The PLC 77
then checks to see if the kettle is cool (block 100). If the kettle
is cool, the clean switch 99 is enabled by the PLC 77 (block 102).
The clean switch may then be actuated to tilt the kettle 18 for
cleaning. The kettle is then cleaned and returned to the upright
position (block 127). As will be recognized, the kettle does not
always have to be cleaned, and an operator may proceed directly to
a cooking cycle wherein the process begins at block 105.
[0139] To begin a popping operation, the operator turns on the
various systems of the popper. For example, the operator would turn
ON the heat switch 80 to the kettle heater 88 to deliver power to
kettle heater 88 through the relay 86. If necessary, the kettle
stir motor 68 would be turned ON at panel 25 or may automatically
be controlled by the PLC 77. The oil pump system 36 and any
components, such as an oil preheater, might also be turned ON as
indicated by block 105. When the kettle heat switch is ON, the PLC
77 monitors the kettle temperature through temperature controller
82 as indicated at block 107 in FIG. 7. As the PLC 77 monitors the
temperature, it continuously checks to determine if the kettle
temperature has risen to the low alarm temperature point which may
indicate either that the kettle is initially heating up or is
returning to its equilibrium start temperature after having cooked
a batch of popcorn (see block 108). As indicated by line 109, the
PLC 77 will continue to monitor the kettle temperature until it has
risen to the low alarm temperature point. When it has reached the
low alarm point, as indicated by line 110, the PLC 77 determines
whether the system is initially being powered up and has not yet
cooked the first batch of popcorn (see block 112). As discussed
hereinabove, the temperature controller has a start override
feature which ignores the first rising temperature pass through the
low alarm temperature which indicates that the system is initially
being powered up. By ignoring the first low alarm temperature
point, the dump cycle is not initiated as indicated by block 114.
Otherwise, when the rising temperature returns to and passes
through the low alarm temperature point, a dump cycle would
normally be initiated according to block 116 because a low alarm
temperature point preceded by another low alarm point (cycle point)
will indicate the end of a cooking cycle and a dump point as
described above.
[0140] As the PLC 77 and temperature controller monitor the kettle
temperature, the PLC 77 checks to see if the kettle temperature has
risen to the equilibrium start temperature which is preferably
approximately 500.degree. F. to 525.degree. F., as indicated by
block 118. If the kettle temperature has not reached the start
temperature, the PLC 77 continues to monitor the kettle until that
temperature is reached according to line 119. When the equilibrium
start temperature has been reached, the system indicates that the
kettle is ready to be loaded with ingredients to cook a batch of
popcorn (line 120). At the start temperature, a buzzer is sounded
and a light flashed intermittently by the PLC 77 to notify the
operator that it is time to load popcorn ingredients and to start
cooking according to block 122. The buzzer will sound
intermittently at ten second intervals and will continue to sound
for ten minutes. If the operator ignores the buzzer for ten
minutes, and no ingredients have been loaded, the buzzer will then
sound continuously.
[0141] When the kettle is ready to cook, the PLC 77 checks to see
if the kettle is upright (block 130). If not, the buzzer sounds
continuously (block 132). If the kettle is upright, the oil pump
switch 106 is enabled (block 134). At this point, the oil pump
switch 106 may be manually actuated to add a premeasured amount of
oil to the kettle as described above (block 135). After oil is
added, the switch 106 will be disabled as discussed above, so that
no more oil may be added until the next cooking cycle.
Alternatively, the PLC 77 may automatically actuate the oil pump
system (block 137) as described above. At that point, popcorn is
also added to initiate a cooking cycle. As may be appreciated, the
automatic pumping of oil may be prevented until after the popcorn
is loaded and a cooking cycle is initiated, as shown by block 139.
In that way, oil introduction is not premature, such as when the
kettle heat switch is turned OFF while the buzzer is sounding and
light flashing to clean the kettle as discussed above. For example,
oil might not be automatically added until after the temperature of
the kettle full of popcorn drops, indicating the initiation of a
cooking cycle.
[0142] The PLC 77 then monitors the kettle temperature in order to
determine if the ingredients have been loaded. As discussed above,
the uncooked ingredients such as corn and oil will act as a heat
load and reduce the kettle temperature when they have been placed
therein. As noted in block 124, the PLC 77 will continue to monitor
the kettle temperature and if no ingredients have been loaded,
i.e., kettle temperature has not dropped (line 125), the buzzer
will continue to sound. If ingredients are loaded, the kettle
temperature will drop somewhat rapidly and will plunge below the
low alarm temperature point (cycle point) 149 of the temperature
controller (see FIG. 8). The buzzer then stops buzzing and the
light stops flashing. Popcorn is then cooked by the kettle (block
128).
[0143] As the buzzer 70 is sounding and light flashing 71, the
operator has the alternative options of turning the machine off or
loading ingredients. If the kettle heat switch 80 is turned OFF,
the system operation essentially returns to block 95 to determine
if it is safe to clean the kettle.
[0144] Returning now to block 128, as the popcorn is cooked, the
kettle begins to again heat up and the temperature controller 82
and the PLC 77 continue monitoring the kettle temperature to
determine if it has recovered or risen back up to the low alarm
temperature point (dump point) 150 and proceeded through that point
on its way back to an equilibrium start temperature (block 108). If
the kettle temperature has risen to,the dump point and it is not an
initial power-up situation, as indicated by line 136, a dump cycle
will be initiated as described hereinabove (block 116). After the
dump cycle is initiated, the system either returns to block 95 if
the kettle heat switch is turned OFF to clean the kettle (line 138)
or will continue to heat the kettle up to its equilibrium start
temperature and will be ready for the next load of ingredients to
cook the next batch of popcorn. As illustrated by block 118 when
the start temperature has again been reached, the buzzer will again
sound to notify the operator to load ingredients. Also, the oil
pump switch will be enabled (block 134), after having been disabled
after oil was added for the previous batch.
[0145] In that way, the automated corn popper 10 of the present
invention only has to be loaded with ingredients to continually
produce successive batches of popcorn. Once the ingredients are
loaded, the operator can ignore the popper and the corn will be
properly cooked and dumped to be ready for serving. An audible
buzzer 70 and flashing light 71 will constantly remind the operator
when a new ingredients load is need and a cooperative working
relationship between the operator and the popper is developed for
producing consecutive batches of fresh popcorn efficiently and
safely while leaving the operator to more important tasks such as
selling the product. Furthermore, the temperature control of the
popper ensures that the right amount of heat is applied to each
batch of popcorn for consistently cooked popcorn. Still further,
the invention controls an oil pump system to ensure that the proper
amount of oil is added without excess.
[0146] FIG. 8 schematically illustrates the kettle temperature as a
function of time through initial power-up and a single cooking
cycle. When the kettle heat is turned on, the kettle 18 heats up
steadily until it reaches an equilibrium start temperature as
indicated by line 140. Preferably, an equilibrium start temperature
will be around 500.degree. F. to 525.degree. F., but may be
adjusted accordingly, depending upon the popcorn load and the size
of the kettle and other heating factors as understood by a person
of ordinary skill in the art. The temperature controller 82 of the
invention is programmed with the equilibrium start temperature and
will automatically monitor the kettle temperature to determine when
it begins to approach the start point 144. The temperature
controller 82 will cycle the heater 88 accordingly to prevent a
large amount of overshoot as indicated by the decreasing slope of
the curve as it approaches line 140. When the start temperature is
reached, the kettle heater 88 is cycled ON and OFF by relay 86 to
maintain the kettle close to the start temperature as indicated in
the curve section designated by reference numeral 142. When
ingredients, such as kernels and oil, are loaded, as indicated by
the load point 144, the kettle temperature drops off somewhat
rapidly as indicated on the curve by reference numeral 146.
Depending upon the popcorn and oil load, the kettle temperature
would drop to a low point 147, for example in FIG. 8, indicated
around 325.degree. F. As the kettle temperature drops, it will drop
through a low alarm point 149. This first low alarm point is
designated the cycle point or cycle temperature, because the PLC 77
sees it as the beginning of a cooking cycle.
[0147] As the popcorn cooks, the kettle temperature again begins to
rise as indicated by reference numeral 148 and will again pass
through the low alarm set point or dump point 150. At dump point
150, the end of the cooking cycle is indicated, and the PLC 77
responds by initiating a dump cycle. Therefore, the cooking cycle
is defined between the cycle point 149 and the dump point 150,
although some cooking of the popcorn will occur before the cycle
point 149 and after the dump point 150.
[0148] The dump cycle is a two-stage dump and empties the cooked
popcorn onto the serving platform to be sold. After the dumping
cycle, the kettle temperature again rises to the equilibrium start
temperature of 525.degree. F. and the heater will again be cycled
ON and OFF to keep the kettle at that temperature indicated on the
curve by reference numeral 152. At the start temperature, the
buzzer 70 will again sound and the light 71 will flash to indicate
to the operator that a batch of popcorn has just finished cooking
and that a new load of ingredients should be added to the
kettle.
[0149] Line 154 illustrates the signal on line 94 from temperature
controller 82 to the PLC 77. When the low alarm temperature points
are reached and exceeded (either cycle point or dump point) the
output from the temperature control cycles oscillates from high to
low at an internal frequency. The square wave signal is used
preferably to drive the intermittent buzzer 70 and flashing light
71. When the temperature of the kettle drops below the low alarm
temperature point, the output of temperature controller 82 stays
high, which indicates that a cooking cycle is ongoing.
[0150] As described, the present invention continuously and
properly cooks popcorn in consecutive batches with minimal
attention by the operator. Because the kettle is controlled by
temperature and the dump cycle is initiated automatically depending
upon the kettle temperature, the popcorn is not burned and is not
affected by operator inattention. Furthermore, the introduction of
oil is controlled for a proper, premeasured amount only once during
each cooking cycle. Messes and spills associated with the prior art
devices are reduced, and a reduction in the delays between fresh
batches of popcorn will increase the production rate of the popper
and thereby increase sales and profitability of the popper.
Furthermore, the present invention insures that a consistent and
proper amount of heat energy is always applied to the corn for
popping. The invention is not particularly susceptible to
environment variations, and will ensure that the proper amount of
heat energy is applied to a batch of corn. Larger batches will get
more heat energy and small batches will get less heat energy to
insure consistent popping.
[0151] Turning now to other aspects and embodiments of the
invention, it will be appreciated that the foregoing detailed
specification is particularly applicable to automatic systems
wherein the kettle is loaded and dumped automatically. Further
alternative embodiments contemplate popping apparatus and methods
wherein the kettle may be automatically or manually loaded and
automatically or manually dumped.
[0152] For example, in one aspect of an alternative embodiment,
audible and/or visual alarms are controlled by the controller to
produce an alarm when the kettle reaches the dumping temperature or
Tdump temperature and the popcorn is finished cooking. This alerts
an operator to observe the kettle dumping or, in a manual mode, to
actuate the control to manually dump it.
[0153] An alarm is also given to alert the operator that the kettle
is being loaded when it has reached a loading temperature, or Tload
temperature, or to actuate the control to load corn and oil when
Tload is reached, or to load the kettle manually when Tload is
reached. In one embodiment of the invention, the dump temperature
and load temperature are approximately the same, and an operator
will dump one batch and load a new batch of ingredients at
approximately the same time.
[0154] Specifically, and referring to FIG. 14, the PLC 77 or other
controller, such as a microprocessor, is coupled to an audible
buzzer 70 and also to one or more indicator lights 71. The
controller 77 operates the audible alarm or buzzer 70 and any
particular indicator lights 71 at particular times to alert an
operator that action is necessary with the system.
[0155] For example, controller 77, upon determining that the kettle
has reached a particular ingredient loading temperature point, will
alert the operator to load the ingredients into the kettle. Once
the kettle has cooked the ingredients and completely popped the
popcorn, the controller will again alert the operator to dump the
kettle, if manual dumping is necessary.
[0156] For each subsequent batch of popcorn, the operator will then
be alerted to load ingredients for the next successive batch and
will be alerted, in a manual dump situation, to dump the corn once
that batch has been popped. Of course, in an automatic dump
situation as described above, dumping will occur automatically.
[0157] Therefore, the present invention provides operator
indications, either visibly or audibly, to alert an operator when
they are supposed to take particular steps, such as adding
ingredients and dumping popcorn.
[0158] In another aspect of the invention, the cooking process is
modified to insure that the first cycle from a cold start, or
alternately, the first and several following cycles from a cold
start, are controlled to insure consistent popcorn quality is
attained in following cycles when heat equilibrium of the system
has been reached.
[0159] In particular, it will be appreciated from the foregoing
detailed description of one embodiment of the invention that the
control system, and specifically temperature controller 82,
analyzes the cycle and the rate of heat rise of the kettle with
respect to a control temperature or some other desired temperature.
As the kettle temperature increases toward the desired temperature,
the temperature controller 82 reduces the heat energy input by
reducing energy to the heating element prior to reaching the
desired temperature. The temperature, however, continues to climb
in a controlled fashion toward the desired level, but is maintained
by this process closer to the desired temperature without the wide
margins of overshoot as in prior systems, such as where the heat
elements are fully energized up until the desired set temperature
is reached. The amplitude of maximum temperature variation around
the desired temperature is significantly reduced, resulting in a
close control of heat energy in the process, and a consistent high
quality, good tasting popcorn. The temperature controller uses a
PID or proportional integral derivative scheme to operate and
control the kettle heater and kettle heat.
[0160] It has been discovered that if the same control logic is
applied, however, to the heat energy in the first cycle from a cold
start, or in immediately following cycles before the apparatus and
sensors reach their own heat equilibrium, those cycles can be
adversely affected to the extent they deviate from optimum cooking
cycle. This occurs, for example, in the following manner.
[0161] If the normal temperature controller PID logic is used on
start up, as the kettle temperature rises toward the desired
temperature in the initial cycle from a cold start, the controller
senses the rate of rise and retards heat input as the temperature
nears the desired temperature. The desired temperature may be a
load temperature or Tload for cooking a first batch of popcorn.
Since the kettle, and the sensor, and other heated components of
the system have most likely not reached thermal equilibrium (as it
exists for subsequent cycles after the first cycle or the first
several cycles have run) the temperature or heat response of the
apparatus is not the same as it is at subsequent cycles wh n
equilibrium has been established. The corn and oil might be loaded
at a load temperature under conditions which result in a cook time
outside the preferred range of about 3.0 to about 3.5 minutes.
Specifically, when the system is not at equilibrium, heat energy
added to the kettle when ingredients are added will not all be
directed to the ingredients. Rather, system components will
continue to absorb heat energy away from the ingredients. As such,
the load temperature may be below the desired point to begin the
cook cycle and the ingredients will not be properly cooked when a
dump temperature is reached. The FIGS. 9, 10 and 11 demonstrate the
effect on time to reach a set, optimum dump temperature for various
Tload temperatures when the corn and oil are actually loaded.
[0162] Accordingly, this embodiment of the invention contemplates a
bypass of the PID aspects of the invention for the first or first
few cooking cycles to insure the cook time from the loading of corn
and oil to reaching Tdump temperature is within the preferred range
of about 3.0 to about 3.5 minutes, and the corn is cooked
properly.
[0163] FIG. 16 is a temperature graph versus time of the kettle
during a popcorn cycle in accordance with one embodiment of the
present invention. Specifically, at point 210, the system is turned
on and the kettle heater begins heating the kettle such that the
temperature rises according to slope 211. In the first cycle of the
heater, where it is initially being heated up from a cold start,
the PID aspects of the temperature controller 82 are not yet
utilized in order to provide more consistent popping of the
popcorn, even in the first cycle, or the first few cycles.
[0164] In earlier systems, the temperature controller 82 was
incorporated immediately and therefore, as the kettle temperature
approached a particular desired temperature, the controller 82
would operate the kettle heaters to slow down heating of the kettle
so that the desired temperature is approached in a more controlled
manner. However, in the first cycle, the components of the system
including the kettle 18, kettle heater 88, thermocouple and other
elements have not yet reached a thermal equilibrium.
[0165] As noted, it was discovered that upon introducing the
temperature controller 82 and its PID aspects in the first cycle,
that the first batch of popcorn would not cook properly.
Specifically, the controller 82 would tend to slow the heating of
the kettle down before all of the components have had a chance to
reach their thermal equilibrium. Thus, when the ingredients were
loaded, heat directed to the kettle and components, which should
have been for the corn, would actually be absorbed as the various
components try to reach their thermal equilibrium.
[0166] Therefore, in accordance with one aspect of the present
invention, the controller 77 overrides the PID features of the
temperature controller 82 for the first cycle and simply turns on
the heaters and lets the kettle temperature ramp up toward a
Tcontrol temperature which is essentially a high limit temperature.
At some temperature prior to reaching Tcontrol, the kettle heater
88 is turned off, such as at point 212.
[0167] Due to the time and temperature lag within the system, which
is cumulative for all the components in the system, the kettle will
still continue to be heated, as indicated by the portion of the
slope designated with reference numeral 213. In fact, the kettle
temperature will pass up through a dump temperature or load
temperature point 214 and will continue to approach Tcontrol. The
controller 77, based upon the power of the heating elements and the
overall mass of the kettle and components, will be programmed to
turn the kettle heat off, such as at point 212, in order to insure
that the overall temperature of the kettle does not reach and
exceed Tcontrol.
[0168] Tcontrol, as discussed further hereinbelow, is a maximum
limit temperature. If the kettle temperature reaches and exceeds
Tcontrol, the kettle heat will turn off and remain off until the
system can be adjusted or fixed. However, in the first cycle, the
Tcontrol temperature is utilized as an upper limit and the
controller 77 turns the kettle heaters off substantially below that
point so that any temperature lag within the system will not bring
the kettle temperature beyond Tcontrol. However, since no PID
control is utilized, heat is directed to the kettle rapidly without
a typical PID slowdown. In that way, the system gets closer to an
equilibrium state on the first cycle.
[0169] As the kettle temperature passes through the Tload point
214, the operator is alerted to add ingredients, since the kettle
is at the desirable cooking temperature.
[0170] If no ingredients are added, the kettle temperature will
climb to its highest point as indicated by a peak point 215 and
will then start to cool because the heater has been turned off.
However, during normal operation, the operator will load the
ingredients, such as popcorn and oil, which present a thermal load
to the kettle as discussed hereinabove. The kettle heat then begins
to plummet according to the portion of the curve indicated by
numeral 216.
[0171] As the corn pops, the various ingredients absorb heat so
that the kettle temperature continues to decrease down to a certain
lowpoint 217. Controller 77 continues to monitor the kettle
temperature and the controller knows that a cooking cycle has begun
when the kettle temperature dips below some chosen temperature
point, such as around 370 degrees.
[0172] Continuing in the cooking cycle, once the ingredients have
absorbed sufficient heat to cook the popcorn, the kettle again
begins to heat up from point 217 as the heaters continue to apply
heat to the kettle. It should be noted that when the kettle
temperature passes through the Tdump point or Tload 218 , as it
cools down after ingredients have been loaded, the PID features of
the temperature controller 82 take over and the system is then
under control of those PID features until the system is turned off
and again begin with the next cold start cycle.
[0173] The PID features of the temperature controller 82 will kick
in when the kettle temperature cools down, regardless of whether
ingredients have been added. For example, even if no ingredients
are added, the heater is turned off in the initial heat cycle at
point 212 and therefore the kettle temperature will inherently cool
down from its peak point 215 to Tdump at point 218. At that point,
the PID features of the temperature controller 82 take over and the
kettle heater will again be turned on to deliver heat to a batch of
ingredients or to keep an empty kettle around the desired
Tload/Tdump point.
[0174] As the heater continues to add heat to the kettle, the
kettle temperature will begin rising, as designated by the portion
of the graph indicated with reference numeral 219. However, the
control of the heater, and therefore the kettle temperature, at
that point is within the PID aspects of controller 82. Therefore,
the temperature will ramp up more gradually to a Tdump point in
those cycles subsequent to the first cycle.
[0175] Once the kettle heats up to the Tdump point 220, several
things might occur. In a system which utilizes a manual dump, the
controller 77 will audibly and/or visibly alert an operator, such
as through an audible buzzer 70 or indicator light 71, that the
load needs to be dumped. This is particularly important as an
operator may be busy and distracted and the popcorn must be dumped
before it burns. Burnt popcorn is a significant problem in certain
vending situations. Alternatively, if the system is operable to
automatically dump the kettle, the kettle may be automatically
dumped at temperature point 220. Controller 82 then operates the
kettle heater, such that the kettle heat is maintained around the
Tload/Tdump temperature as indicated by reference numeral 222. As
the system reaches equilibrium, the overshoots associated with
region 222 will decrease for subsequent cycles.
[0176] At that point, the next batch of ingredients should be
loaded. Therefore, the Tdump is also indicated as Tload. Once the
next batch of ingredients is loaded, such as at point 224, the
temperature of the kettle will again drop as it repeats another
cooking cycle as previously described. For each subsequent cycle,
the kettle and kettle heater are under the control of the PID
aspects of the temperature controller.
[0177] While one embodiment of the invention is described with
respect to bypassing the PID aspects of the temperature controller
for the first cycle, so that the system may reach equilibrium and
the first batch of popcorn is cooked properly, such a feature may
be incorporated with more than the first cycles, such as the first
two or three cycles, in order to insure that equilibrium is
properly obtained before turning the kettle heater over to the
control of the PID aspects of the temperature controller.
Therefore, the invention is not limited to simply a single override
of normal kettle temperature control within the first cycle.
[0178] As discussed above, should the kettle temperature meet or
exceed the set Tcontrol temperature, the controller 77 recognizes
an over temperature condition and will shut off the heater to the
kettle.
[0179] FIG. 15 discloses a flow chart for operation of one
embodiment of the kettle where, more specifically, the kettle is
heated according to step 226. The controller 77 determines if the
kettle is starting from a cold start (step 228). If it is, the
kettle is heated without PID control to a set point and the heater
is then turned off (step 230). Then, controller 77 determines if
the kettle temperature is cooled to Tload. If it has, whether that
is through the kettle simply cooling down because heat to the
kettle was turned off, or the loading of ingredients, the
controller 77 initiates the PID aspects of the temperature
controller 82 for subsequent cooking cycles (steps 232 and 234). If
the kettle is not starting from a cold start as it is being heated,
the PID control aspects are utilized (step 234).
[0180] Again, while the example is given for a single start up
cycle, numerous cycles might be utilized from a cold start before
equilibrium is reached, and therefore control of the kettle heating
may not be turned over to the PID aspects of temperature controller
82 until after several cycles.
[0181] In another aspect of the invention, the foregoing detailed
description describes the delivery of oil by means of a pump and
timer. It has been found that calibration of the timer is an
awkward, trial and error process, not enjoyed by most operators.
Accordingly, this invention further contemplates the use of the
controller 77 to control delivery of consistently measured amounts
of oil. The controller is operable to be placed in a learn mode
upon the initial cooking situations. The pump is started and oil is
dispensed into a desired measurement receptacle. When the exact
amount is dispensed, the pump is stopped. The control system
"learns" this sequence to so that any further initiation of the oil
dispensing cycle causes the same amount of oil to be dispensed.
Therefore, the aforementioned timer and trial and error process is
wholly eliminated with the control provided by controller 77.
[0182] For example, when initially beginning the cooking of
popcorn, the oil system is placed in a measurement mode in order to
set how much oil will be automatically added each time in the
cooking cycle or will be added manually upon engagement of an oil
pump button or switch at the start of a cook cycle.
[0183] The timer associated with the oil pump is bypassed with the
controller 77 controlling the pump timing in order to deliver the
proper amount of oil for each batch of popcorn. To that end, oil
pump control circuitry 200 is operably coupled to the controller 77
to place the controller 77 in a "learn" mode (see FIG. 14).
[0184] Upon initiating the oil pump control circuitry 200 to place
the controller 77 in a learn mode, and upon engaging the pump
switch 106, the oil pump begins pumping oil and the controller 77
monitors how long the oil pump switch is engaged. The oil pump
control 200 places the controller 77 into a learn mode so that it
monitors the length of time that the switch 106 is engaged. Once
the switch 106 is disengaged, the controller 77 remembers the
particular length of time. In that way, a particular length of time
may be associated with a particular amount of oil being dispatched.
The oil pump control circuitry 200 may be implemented with the
existing circuitry, such as by manipulating, in sequence, switch
106 and other switches associated with the oil pump and coupled to
controller 77.
[0185] As an example, the oil pump may be capable of dispensing one
half of a cup of an oil in 2 to 3 seconds. If the oil pump control
200 is engaged and the controller 77 is set up to learn, the
controller 77 will remember the time of 2 to 3 seconds that the
switch is initially engaged and will dispense the amount of oil
associated with that time, that is, approximately one half of a cup
of oil. The controller may then be taken out of learn mode by
control 200. Thereafter, each time switch 106 is engaged,
approximately one-half cup of oil is dispensed.
[0186] To determine the proper amount of oil, an operator may hold
a measuring implement, such as a measuring cup, under the oil inlet
leading to the kettle. The switch 106 is then engaged for a
particular amount of time in order to deliver a desired amount of
oil to the measuring cup. Once that desired amount of oil has been
delivered, the controller will remember.
[0187] For each subsequent batch of popcorn, the controller will
operate the oil pump 104 to dispense oil for a particular amount of
time. In that way, the trial and error associated with setting a
specific oil pump timer to deliver the proper amount of oil, is
eliminated. Rather, the operator may watch the amount of oil which
is initially delivered and will disengage the switch 106 when the
proper amount is delivered. Assuming that the oil pump is
consistent in its pumping rate, the controller 77 will then
remember the time and operate the pump for the proper time to
insure the proper amount of oil. The operator does not care about
the specific time, but rather wants to insure that a specific
amount of oil is added each time, regardless of how long the oil
pump has to operate to do so. Therefore, the present invention
insures that a proper amount of oil is added each time and
eliminates the need for the operator to adjust oil pump timers and
the trial and error process to measure the oil added to the
kettle.
[0188] In another aspect of the invention, it is noted that popcorn
machines may be used not only to pop corn with a salt seasoning,
but also to pop corn in sugar, producing a coated, sweet
caramel-like tasting popcorn product. This product is perhaps more
popular in European environments than in U.S. Use of a popper
according to any embodiment described above can produce such
product, but if the same temperatures are used, the sugar can be
heated too much and burned. Accordingly, one embodiment of the
invention contemplates the use of control circuitry enabling the
cooking temperatures to be adjusted to the popcorn product desired.
While this may be at the expense of optimum popped corn when lower
temperatures are selected for "sugar" corn, other operating
processes as described herein are retained.
[0189] Specifically, salt popcorn may be popped at a temperature
of, for example, 525 degrees F. However, popping sugar popcorn at
such a temperature would burn the sugar. Therefore, one embodiment
of the present invention utilizes a cooking temperature control
circuit 202 which is coupled to controller 77 for varying the
cooking temperature of the kettle through the temperature
controller 82.
[0190] Specifically, the cooking temperature control circuit 202
may include a number of switches or other circuits, such as circuit
jumpers, such that it is slightly higher for salt popcorn and
slightly lower for sugar popcorn. The cooking temperature control
circuit 202 may be set during manufacturing, such as by utilizing
specific jumpers associated with controller 77 to select a
temperature for Tload/Tdump. Each jumper may represent a certain
temperature range for reducing a salt corn temperature of Tload to
a sugar corn Tload. More precise temperature adjustments might be
provided by using potentiometers with the jumper to vary the
selected temperature with controller 77.
[0191] Alternatively, the cooking temperature control circuit 202
might be accessible to the operator, such that the operator may
select the type of popcorn to be cooked. For example, a simple
two-position switch might be used, with one for salt and one
position for sugar.
[0192] Generally, popcorn poppers will be set up for cooking one
type of popcorn and will hot be switched back and forth between
types of popcorn. For a single use situation, hard wiring of a
cooking temperature control circuit 202 at the manufacturing level
may be desirable. However, if a particular machine will be switched
back and forth and do double duty with both salt popcorn and sugar
popcorn, operator-accessible control circuitry might be
utilized.
[0193] In yet another aspect of the invention, it is desirable to
provide a visual indicator in a popper that the kettle is not ready
for corn loading, such as before the kettle temperature has reached
Tload. Accordingly, on startup, the controller in an automatic dump
machine tilts the kettle, such as to a 45 degree angle, for
example, to indicate it is in a non-loading portion of the cycle.
The kettle is leveled when its temperature reaches a desired Tload
to visually indicate it is ready for loading. The control system
accomplishes this similar to the way in which the kettle is
controlled for an automatic dump as will be understood by a person
of ordinary skill in the art from the foregoing description.
[0194] Finally, it will be appreciated one embodiment of the
invention contemplates a manual operation of the kettle position
through dump and return, and which is particularly enhanced by the
provisions of the load and dump alarms described above.
[0195] The present invention also provides the proper amount of
heat to maximize kernel expansion at popping. With the heat
maintained at the proper level, the temperature of the corn and the
steam pressure in the kernels will cooperate to provide consistent
and high kernel expansion. With the present invention, popping
expansion of rates of 1:50 have been achieved which are a
significant improvement over the 1:44 or lower rates achieved by
the prior art.
[0196] While the present invention has been illustrated by a
description of various embodiments and while these embodiments have
been described in considerable detail, it is not the intention of
the applicants to restrict or in any way limit the scope of the
appended claims to such detail. Additional advantages and
modifications will readily appear to those skilled in the art. The
invention in its broader aspects is therefore not limited to the
specific details, representative apparatus and method, and
illustrative example shown and described. Accordingly, applicant
intends to be bound only by the claims appended hereto.
[0197] What is claimed is:
* * * * *