U.S. patent application number 09/866086 was filed with the patent office on 2001-10-04 for oven device for rapid heating of food items.
This patent application is currently assigned to Hatco Corporation. Invention is credited to Wenzel, Gerhard H., Witt, Allan E..
Application Number | 20010025842 09/866086 |
Document ID | / |
Family ID | 24071980 |
Filed Date | 2001-10-04 |
United States Patent
Application |
20010025842 |
Kind Code |
A1 |
Witt, Allan E. ; et
al. |
October 4, 2001 |
Oven device for rapid heating of food items
Abstract
An oven device for final finishing of a food item includes an
oven housing defining a heating cavity configured to receive at
least one food item to be heated, and an upper heating unit within
the oven housing above the heating cavity. The upper heating unit
includes a heating element that generates radiant heat directed
onto the food item in the heating cavity. The oven housing includes
at least one reflective panel for distributing radiant heat within
the heating cavity. The upper heating element includes a
rapidly-heating, high-intensity heating element capable of being
cycled on for final finishing of the food item when the food item
is received in the heating cavity, and capable of being cycled off
when final finishing is not being performed. The final finishing
typically includes browning a top surface of the food item, or
melting a topping onto the top surface of the food item.
Inventors: |
Witt, Allan E.; (Brown Deer,
WI) ; Wenzel, Gerhard H.; (Sussex, WI) |
Correspondence
Address: |
Alistair K. Chan
FOLEY & LARDNER
Firstar Center
777 East Wisconsin Avenue
Milwaukee
WI
53202-5367
US
|
Assignee: |
Hatco Corporation
|
Family ID: |
24071980 |
Appl. No.: |
09/866086 |
Filed: |
May 25, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
09866086 |
May 25, 2001 |
|
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|
09520294 |
Mar 7, 2000 |
|
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6262396 |
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Current U.S.
Class: |
219/411 ;
219/405 |
Current CPC
Class: |
A47J 37/0641 20130101;
A47J 37/0623 20130101; F24C 7/00 20130101 |
Class at
Publication: |
219/411 ;
219/405 |
International
Class: |
A21B 002/00 |
Claims
What is claimed is:
1. An oven device for final finishing of a food item, comprising:
an oven housing defining a heating cavity therein, the heating
cavity configured to receive at least one food item to be heated by
the oven device; the oven housing including at least one reflective
panel for distributing radiant heat within the heating cavity; and
an upper heating unit disposed within the oven housing above the
heating cavity, wherein the upper heating unit includes an upper
heating element; the upper heating unit configured to generate
radiant heat which is directed onto the at least one food item when
the at least one food item is received in the heating cavity,
wherein the upper heating element includes a rapidly-heating,
high-intensity resistive ribbon heating element capable of being
cycled on for final finishing of the at least one food item when
the at least one food item is received in the heating cavity, and
capable of being cycled off when such final finishing is not being
performed, the resistive ribbon heating element configured to
provide radiant energy directly to the food item.
2. The oven device of claim 1 wherein the reflective panel
comprises a metallic panel having a corrugated surface pattern.
3. The oven device of claim 2 wherein the corrugated surface
pattern has a longitudinal profile oriented parallel to a planar
orientation of the resistive heating element.
4. The oven device of claim 3 wherein the corrugated surface
pattern is linear and horizontal.
5. The oven device of claim 3 wherein the corrugated surface
pattern is linear and vertical.
6. The oven device of claim 1 wherein the reflective panel is
parallel to a back wall of the oven housing.
7. The oven device of claim 1 wherein the at least one reflective
panel is generally parallel to one or more of a back wall, a side
wall, a top or a base of the oven housing.
8. The oven device of claim 1 wherein the reflective panel has an
interchangeable reflective insert.
9. The oven device of claim 1 wherein the reflective panel is
unitarily formed.
10. The oven device of claim 1 wherein the reflective panel is made
from stainless steel.
11. An oven device for final finishing of a food item, comprising:
an oven housing defining a heating cavity therein, the heating
cavity configured to receive at least one food item to be heated by
the oven device; the oven housing including at least one reflective
panel for distributing radiant heat within the heating cavity; an
upper heating unit disposed within the oven housing above the
heating cavity, wherein the upper heating unit includes an upper
heating element; a lower heating unit disposed within the oven
housing below the heating cavity, wherein the lower heating unit
includes a lower heating element; the upper and lower heating units
configured to generate radiant heat which is directed onto the at
least one food item when the at least one food item is received in
the heating cavity, the upper and lower heating elements each
including a rapidly-heating, high-intensity resistive ribbon
heating element capable of being cycled on for final finishing of
the at least one food item when the at least one food item is
received, and capable of being cycled off when such final finishing
is not being performed, the resistive ribbon heating element
configured to provide radiant energy directly to the food item.
12. The oven device of claim 11 wherein the reflective panel
comprises a metallic panel having a corrugated surface pattern.
13. The oven device of claim 12 wherein the corrugated surface
pattern has a longitudinal profile oriented parallel to a planar
orientation of the resistive heating element.
14. The oven device of claim 13 wherein the corrugated surface
pattern is linear and horizontal.
15. The oven device of claim 13 wherein the corrugated surface
pattern is linear and vertical.
16. The oven device of claim 11 wherein the reflective panel is
parallel to a back wall of the oven housing.
17. The oven device of claim 11 wherein the at least one reflective
panel is parallel to one or more of a back wall, a side wall, a top
or a base of the oven housing.
18. The oven device of claim 11 wherein the reflective panel has an
interchangeable reflective insert.
19. The oven device of claim 11 wherein the reflective panel is
made from stainless steel.
20. An oven device for final finishing of a food item, comprising:
oven housing means for defining a heating cavity for receiving at
least one food item; resistive ribbon heating means within the oven
housing means for generating high-intensity radiant heat and for
directing the heat directly onto a top surface of the at least one
food item when the at least one food item is within the heating
cavity; means for distributing the radiant heat within the heating
cavity; and means for cycling the radiant heat on for final
finishing of the at least one food item when the at least one food
item is received within the heating cavity and for cycling the heat
off when such final finishing is not being performed.
Description
RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. patent
application Ser. No. 09/520,294, filed Mar. 7, 2000, entitled "Oven
Device for Rapid Heating of Food Items", which is hereby
incorporated by reference.
FIELD OF THE INVENTION
[0002] The invention relates generally to an oven device for
rapidly heating food items. More particularly, the invention
relates to an improved oven device for rapid melting or browning of
the top surfaces of food items, which may typically involve melting
or browning toppings or side-dishes which have been applied onto or
beside pre-cooked food components. The oven device also provides
the capacity to simultaneously heat the plate or other support
assembly for the food items.
BACKGROUND OF THE INVENTION
[0003] In the restaurant business, components of individual food
items or of complete meals (e.g., hamburger patties; broiled beef;
fried chicken; etc.) are often pre-cooked at cooking locations
around the restaurant's kitchen. These pre-cooked food components
are then assembled into completed food items or meals before
presentation to the customer. During the final assembly process,
various toppings or side-dishes are served on or beside the
pre-cooked components, and the toppings or side-dishes are melted
or browned before the food items or meals are served. For example,
sliced or grated cheese is often melted onto a pre-cooked hamburger
patty to make a cheeseburger, or whipped potatoes are browned after
being added as a side-dish to a plate of fried chicken. Together
with melting or browning the top surfaces of the food items or
complete meals, it is often necessary or desirable to
simultaneously heat the serving plate or other assembly on which
the food items or meals are served in order to provide the
perception of a fresh-cooked hot meal. For example, Mexican
restaurants typically serve fajitas on a sizzling iron skillet.
Ovens used to perform the finishing functions of melting or
browning the toppings of the food items before they are served can
be referred to as "thermal finishers".
[0004] One existing system for performing these functions employs a
plate heater to heat the serving plate, and a gas over-fired
broiler known in the restaurant industry as a "Salamander" broiler
to perform the final finishing (i.e., the melting or browning) of
the toppings or side dishes. This system, however, has significant
disadvantages. The over-fired gas broiler generates a tremendous
amount of heat (e.g., 40,000 to 60,000 BTUs), much of which is
wasted since the Salamander broiler must be left on continuously
since it takes a significant period of time to warm up, even though
the broiler is used for only a fraction of the time that it is
turned on. Also, since the Salamander broiler is open to the
kitchen, the high heat output level of the broiler heats up the
kitchen and requires the installation of kitchen exhaust fans in
order to exhaust the excess heat. Thus, the Salamander broiler is a
wasteful system for melting toppings and warming serving
plates.
[0005] Another existing system employs a conveyor oven which must
also be turned on all of the time, and is relatively slow in
comparison to the Salamander broiler. The slow heating time of this
alternative type of system is an important disadvantage in, for
example, the fast-food industry. In addition, since the entire
plate or support assembly passes through the heating cavity via the
conveyor, the entire plate including its rim becomes hot such that
the plate cannot be efficiently handled by food service workers
without using insulated gloves or other methods.
[0006] Thus, it would be advantageous to provide an improved oven
device for rapid heating of food items which overcomes these and
other disadvantages of existing systems. It would be advantageous
to provide such an oven device which can be turned on and off as
needed, thereby decreasing both energy usage and the amount of heat
vented into the kitchen as compared to an oven which must be left
on continuously. The decreased amount of heat vented into the
kitchen would allow the exhaust hood or other ventilation method
needed to exhaust the excess heat to be dispensed with, and would
result in savings in air conditioning and ventilation costs. It
would also be advantageous to provide an oven device for rapid
heating of food items capable of heating the items significantly
faster than is possible using existing conveyor oven systems. Also,
it would be advantageous to provide an oven device for rapidly
heating food items which is capable of heating only a portion of
the plate or support assembly for the items such that the plate or
support assembly could be efficiently handled by the restaurant's
food service workers. For example, it would be advantageous to
provide such an oven device wherein the rims of plates holding the
food items would not be subjected directly to the heat source and
would not be subjected to the radiant heat of the oven. This would
allow food service workers to pick up the plates by their rims
without using insulated gloves or other methods.
SUMMARY OF THE INVENTION
[0007] One embodiment of the invention provides an oven device for
final finishing of a food item. The oven device includes an oven
housing defining a heating cavity therein and an upper heating unit
disposed within the oven housing above the heating cavity, and at
least one reflective panel for distributing radiant heat within the
heating cavity. The heating cavity is configured to receive at
least one food item to be heated by the oven device. The upper
heating unit includes an upper heating element. The upper heating
unit generates radiant heat which is directed onto the at least one
food item when the at least one food item is received in the
heating cavity. The upper heating element includes a
rapidly-heating, high-intensity heating element capable of being
cycled on for final finishing of the at least one food item when
the at least one food item is received in the heating cavity, and
capable of being cycled off when such final finishing is not being
performed.
[0008] Another embodiment of the invention provides an oven device
for final finishing of a food item including an oven housing
defining a heating cavity therein, and at least one reflective
panel for distributing radiant heat within the heating cavity, and
upper and lower heating units disposed within the oven housing
above and below the heating cavity, respectively. The heating
cavity receives at least one food item to be heated. The upper and
lower heating units include an upper and a lower heating element,
respectively. The upper and lower heating units generate radiant
heat which is directed onto the at least one food item when the at
least one food item is received in the heating cavity. The upper
and lower heating elements each include a rapidly-heating,
high-intensity heating element which can be cycled on for final
finishing of the at least one food item when the at least one food
item is received, and of being cycled off when such final finishing
is not being performed.
[0009] Another embodiment of the invention provides an oven device
for final finishing of a food item including oven housing means for
defining a heating cavity for receiving at least one food item,
resistive ribbon heating means within the oven housing means for
generating high-intensity radiant heat and directing the heat onto
a top surface of the at least one food item when the at least one
food item is within the heating cavity, means for distributing the
radiant heat within the heating cavity, and means for cycling the
radiant heat on for final finishing the at least one food item when
the at least one food item is received within the heating cavity
and for cycling the heat off when such final finishing is not being
performed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The present invention will become more fully understood from
the following detailed description, taken in conjunction with the
accompanying drawings, wherein like reference numerals refer to
like parts, in which:
[0011] FIG. 1 is a perspective view of an oven device for rapidly
heating food items (i.e., a thermal finisher) according to one
embodiment of the invention;
[0012] FIG. 2 is a front view of the oven device shown in FIG.
1;
[0013] FIG. 3 is a side view of the oven device shown in FIG.
1;
[0014] FIG. 4 is a rear view of the oven device shown in FIG.
1;
[0015] FIG. 5 is a top view of the oven device shown in FIG. 1,
including an illustration of the geometric arrangement of the
internal heating elements;
[0016] FIG. 6 is a diagram showing the layout of a timer board used
by the oven device of FIG. 1, which provides the user interface as
also shown in FIG. 2;
[0017] FIG. 7 is a rear exploded perspective view of a reflective
wall panel for the oven device;
[0018] FIG. 8 is a front elevation view of a reflective wall panel
for the oven device; and
[0019] FIG. 9 is a right side elevation view of a reflective wall
panel for the oven device.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020] Referring to FIGS. 1-5, an oven device 10 in accordance with
one embodiment of the invention includes an oven housing comprised
of a base 12, left and right side walls 14 and 16 attached to and
extending upward from the left and right edges of base 12, a rear
wall 18 attached to and extending upward from the rear edge of base
12 between side walls 14 and 16, and a top 20 attached to left and
right side walls 14 and 16 and rear wall 18 opposite base 12. Base
12, side walls 14 and 16, rear wall 18 and top 20 are formed of
food-grade stainless steel, each with an internal insulation layer
for containing heat generated by oven device 10.
[0021] Base 12, left and right side walls 14 and 16, rear wall 18
and top 20 together define a cavity 22 having a bottom portion 24,
a lower middle portion 26, an upper middle portion 28, and a top
portion 30. Bottom portion 24 is disposed above and adjacent to
base 12 and is configured to support a lower heating unit 32. Lower
middle portion 26 forms a heating cavity 34 disposed above base
heating unit 32 and open to the front of oven device 10 for
receiving one or more food items 36. Although FIGS. 2 and 3 show
food items 36 as including food served in a casserole, food items
36 can include many types of foods and complete meals which
typically go through a final finishing process in restaurants and
cafeterias before being served to customers. Such food items can be
served on plates or other support assemblies. For example, food
items 36 can include cheeseburgers served on plates, or Mexican
dinners served on platters. Food items 36 can also be served
without any plates or serving dishes. For example, food items 36
could be foil-wrapped baked potatoes, with cheese or other toppings
which can be melted or browned by oven device 10.
[0022] Upper middle portion 28 of cavity 22 is disposed above
heating cavity 34 and is configured to support an upper heating
unit 38. Top portion 30 is disposed above and adjacent to upper
heating unit 38 and is configured to support a control unit 40.
Thus, cavity 22 of oven device 10 is configured to receive lower
and upper heating units 32 and 38 supported on bottom and top of
heating cavity 34, with lower and upper heating units 32 and 38
being configured to provide heat from both the top and the bottom
of any food items 36 placed within heating cavity 34. Control unit
40 is then used to control the lower and upper heating units 32 and
38.
[0023] As described further below, control unit 40 has the
capability of independently controlling the heating cycles of
heating units 32 and 38, preferably through the use of one or more
microprocessor-controlled heating sequences that are preprogrammed
or preset to meet the heating needs of particular types of food
items. In one embodiment, control unit 40 can be programmed to run
one of five different predetermined heating sequences via
activation of a corresponding one of five different push-button
switches by the food service operator, with each heating sequence
capable of independently varying the cycle times and power levels
of both heating units 32 and 38. The push-buttons can thus be used
to activate the proper heating sequence for each of five different
food items 36 with varying requirements.
[0024] Lower and upper heating units 32 and 38 each comprises a
stainless steel box or housing sized to fit within bottom and upper
middle portions 24 and 28 of cavity 22, respectively, so that
heating units 32 and 38 can be securely attached within oven device
10 by, for example, welding or fasteners (e.g., screws, rivets).
Referring specifically to FIG. 3, the top surface of lower heating
unit 32 is formed of a lower glass panel 42, and the bottom surface
of upper heating unit 38 is formed of an upper glass panel 44.
Glass panels 42 and 44 are attached to the edges of the respective
housings of heating units 32 and 38. One or more
electrically-powered heating elements 46 are mounted in lower
heating unit 32, and one or more such heating elements 48 are
mounted in upper heating unit 38. Heating elements 46 and 48 are
adapted to focus radiant energy into heating cavity 34 through
respective glass panels 42 and 44. Each heating element 46 and 48
receives a flow of electricity under the control of a control board
mounted within control unit 40.
[0025] When food items 36 are placed within heating cavity 34
between lower and upper glass panels 42 and 44, heat generated by
heating elements 46 and 48 is directed or focussed toward those
food items 36 from both above and below the food items. The heat
from lower heating unit 32 performs the dual functions of heating
the plate or other support assembly and heating the food product
itself, and the heat from upper heating unit 38 browns or melts the
top of the food product.
[0026] Heating elements 46 and 48 are preferably resistive heating
elements which employ a thin, high-intensity resistive ribbon
element which heats up to an orange glow almost instantaneously
(e.g., in less than about 1.0 or 0.5 second). Oven device 10 is
thus able to reach its operating temperatures very quickly, which
provides an important advantage in the fast-food industry. Heating
elements 46 and 48 can be, for example, Halient elements available
from EGO North America. Alternatively, other types of heating
elements can be used, such as elements which use a resistive wire
coil. Preferably, the elements will be capable of being heated to
their operating temperatures quickly, with the maximum allowed
heating time depending on the application and the needs of the
particular restaurant or operator.
[0027] The size and number of heating elements 46 and 48 within
heating units 32 and 38 will depend on the particular food service
application, and to a large extent will depend on the sizes and the
shapes of the plates or other food support assemblies used. In one
embodiment of oven device 10 designed for a Mexican restaurant that
uses oversized oval platters for serving meals, heating elements 46
and 48 are selected as shown in FIGS. 3 and 5. In particular,
mounted in lower heating unit 32 is a single Halient heating
element having a nine (9) inch diameter and a power rating of 2500
W with a supply voltage of 240 VAC (EGO Part No. 10.53111.043), and
mounted in upper heating unit 38 is an array of four Halient
heating elements, each having a six (6) inch diameter and a power
rating of 1250 W with a supply voltage of 240 VAC. Heating elements
having diameters of nine and six inches and power ratings of 2400 W
and 1200 W, respectively, with a 208 VAC supply are also available.
Note the geometrical arrangement of the upper heating elements 48
(as best shown in FIG. 5) provides good heat coverage even for the
oversized oval platters which are used by the above-referenced
Mexican restaurant.
[0028] In an alternate embodiment of oven device 10 designed for
use with regular circular serving plates (not shown), a single
Halient heating element with a diameter of nine (9) inches is
mounted in each of lower and upper heating units 32 and 38, with
the two heating elements mounted opposite each other. Where the
serving plates have a diameter larger than that of the heating
elements, the rims of the plates placed between these two heating
elements will not receive direct radiant energy from the heating
elements. In this case, the rims of the plates will tend to remain
relatively cool during the short time required to perform the final
finishing process (i.e., melting or browning the food items), thus
allowing the food service workers to handle the plates by their
rims without the need for insulated gloves or other methods (e.g.,
using tongs to handle the heated plates). For example, if an 11
inch diameter plate is placed between lower and upper nine inch
diameter heating elements for the short time needed to melt cheese
placed on top of a pre-cooked hamburger patty, the rim of the plate
will tend to remain cool enough to allow handling by a food service
worker without the need for any special equipment.
[0029] Other types, sizes, numbers and geometrical arrangements of
heating elements 46 and 48 are possible depending upon the
particular oven application, and on the size and shape of the
serving plates regularly used in that application. Such alternative
oven configurations will be readily apparent to those of skill in
the art.
[0030] Lower and upper glass panels 42 and 44 are clear glass
panels which pass most of the radiant energy generated by heating
elements 46 and 48 to heating cavity 34 to heat any food items 36
placed therein by the food service operator. In one embodiment,
glass panels 42 and 44 are tempax barosilicate glass panels made by
Schott America of New York, sold under the SCHOTT glass tradename.
These panels are formed of a clear, quartz glass that transmit or
pass about 99% of the radiant energy. Other types of glass could
also be used, including Ceran glass, although Ceran glass may not
transmit radiation as efficiently as the Schott glass.
[0031] As discussed above, the application of electrical power to
heating elements 46 and 48 in heating units 32 and 38 is controlled
by control unit 40. Unit 40 comprises a stainless steel housing
sized to fit within top portion 30 of cavity 22, such that unit 40
can be securely attached within oven device 10 using, for example,
welding or fasteners (e.g., screws, rivets). Control unit 40 has a
front surface 50 that provides an operator interface having a
number of input devices (e.g., switches) for allowing the operator
to control the operations of oven device 10, and a number of output
devices (e.g., displays) for displaying status information to the
operator.
[0032] Control unit 40 includes an electronic controller/output
circuit board (not shown) mounted within its housing and an
operator interface board 52 mounted to front surface 50. Operator
interface board 52 is mounted such that the input devices (e.g.,
switches) on board 52 are accessible to the operator (e.g., through
apertures in front surface 50), and such that the output devices
(e.g., displays) on board 50 are visible to the operator (e.g.,
also via apertures in front surface 50). Of course, the input and
output devices could also be mounted directly onto front surface
50. Control unit 40 provides programmable control of upper and
lower heating units 32 and 38, using timer circuits or a
microprocessor-based controller. In one embodiment, control unit 40
provides the operator or food service worker with a plurality
(e.g., five) of programmable sequences for independently operating
lower and upper heating elements 46 and 48, with a corresponding
plurality (e.g., five) of push-buttons provided to allow for
one-touch control for each sequence.
[0033] Each sequence can be programmed for a different type of food
item, thereby allowing the food service operator to select one of
the plurality (e.g., five) of predetermined sequences simply by
pushing a push-button. For example, oven device 10 could be
configured or programmed such that one push-button triggers a first
preset sequence for operating lower and upper heating elements 46
and 48 in a first manner suitable for final finishing of fajitas, a
second push-button triggers a second present sequence for operating
elements 46 and 48 in a second manner suitable for final finishing
of enchiladas, etc. In this way, oven device 10 can be programmed
to provide a simple operator interface allowing even operators with
little experience and training to accurately control the heating of
many food items.
[0034] As best shown in FIG. 6, operator interface board 52
supports an alphanumeric display 54, two amber LEDs 56a and 56b,
eight push-button (i.e., momentary) input switches 58a-58h, and
five green LEDs 60a-60e. Display 54 includes a number (e.g., four)
of seven-segment LEDs. Lower amber LED 56a indicates status of
lower heating element(s) 46 and upper amber LED 56b indicates
status of upper heating element(s) 48. The push-button input
switches comprise five program switches 58a-58e, an up-arrow switch
58f, a down-arrow switch 58g, and an enter switch 58h. The five
green LEDs 60a-60e indicate the status of each of the five programs
selectable by the operator using program switches 58a-58e.
[0035] The electronic controller/output circuit board mounted
within control unit 40 includes four line voltage output circuits,
a timer circuit and an annunciator (e.g., a buzzer circuit). Each
line voltage output circuit includes a load-carrying triac. Triacs
are solid-state switches capable of reliably handing a large number
(e.g., hundreds of thousands) of power cycles without failure. For
oven device 10, the controller/output circuit board receives four
voltage inputs including a 12-24 V input voltage, a first 208-240
VAC line voltage input (L1), a second 208-240 VAC line voltage
input (L2), and a third 208-240 VAC line voltage input (L3), and
then generates four voltage outputs including a first line voltage
output for two upper heating elements 48 (circuit A), a second line
voltage output for two upper heating elements 48 (circuit B), a
third line voltage output for lower element 46 (circuit C) and a
fourth line voltage output for lower element 46 (circuit D). Each
of the triacs has the capability to handle a 12 A resistive
load.
[0036] The timer circuit on the controller/output circuit board
operates the triacs semi-independently to control the supply of
line voltages applied to heating elements 46 and 48. In one
embodiment, the timer circuit is a programmable timer configured to
run from 0 to 300 seconds in single second increments. Preferably,
the timer circuit includes a microprocessor circuit configured
(i.e., programmed) to perform the various functions described
below. As noted, the timer circuit provides a plurality (i.e.,
five) of programmable sequences for operating the upper and lower
heating elements, with each "run-time" sequence being triggered by
the edge signal from one of the five program switches 58a-58e. In
the microprocessor embodiment of the timer circuit, the
microprocessor stores five different programs, each used for a
different type of food item 36. Each program allows the restaurant
owner to select the on-time, off-time and amount o f power to be
applied to food items 36 by each of heating elements 46 and 48. By
carefully managing the heating elements, food items 36 can be
heated quickly without being burned. Along with the five
programmable sequences for both sets of elements (i.e., lower and
upper), control unit 40 also provides a programmable stand-by
sequence, an auto-off mode, and a curing mode sequence. Each of
these sequences is further described as follows:
[0037] Run-Time Sequence: Lower and upper heating elements 46 and
48 both have 5 separately programmable timing sequences and 10
selectable power levels. The particular values for the timing
sequences and selectable power levels used for the final finishing
(e.g., browning, melting) of a particular food item 36 are
determined via empirical testing.
[0038] Timing Sequences: The time values for lower and upper
heating elements 46 and 48 represent their "on" times and the time
value for both heating elements 46 and 48 is any value between 0
and 300 seconds. When a sequence is triggered, the lower and upper
heating elements are both de-energized at the same time. For
example, if the "on" time for the upper element is 45 seconds, and
the "on" time for the lower element is 65 seconds, the lower
element is energized 20 seconds before the upper element so both
elements are de-energized at the same time.
[0039] Selectable Power Levels: The power levels of heating
elements 46 and 48 are selected by varying the duty cycle of the on
time and may be set in 5% or 10% power level increments. For
example, a 10% power level is achieved by cycling on for 4 seconds
and off for 36 seconds, 20% power level is achieved using 4 seconds
on and 16 seconds off, 30% power level is achieved using 4 seconds
on and 9 seconds off, 40% power level is achieved using 4 seconds
on and 6 seconds off, 50% power level is achieved using 4 seconds
on and 4 seconds off, 60% power level is achieved using 6 seconds
on and 4 seconds off, 70% power level is achieved using 9 seconds
on and 4 seconds off, 80% power level is achieved using 10 seconds
on and 2.5 seconds off, 90% power level is achieved using 18
seconds on and 2 seconds off, and 100% power level is achieved by
remaining the heating elements 46 and 48 continuously on.
[0040] Stand-By Mode: When a run-time sequence is not being
performed, oven device 10 remains in a stand-by mode. During the
stand-by mode, the upper elements cycle at a selectable power
level, and the display indicates that the oven is in stand-by mode
by displaying "rEdY". The power levels which can be selected during
the stand-by mode include the 10%, 20%, 30%, 40%, 50%, 60% and 70%
on time power levels. The purpose of stand-by mode is to maintain
the internal temperature of oven device 10 at an elevated
temperature (e.g., 300-400.degree. F.) in order to further reduce
the cooking time of the food items. This elevated temperature
depends on the above-described cycle time. In an alternative
embodiment, the heating elements are not powered in the standby
mode, further conserving energy used by oven device 10.
[0041] Auto-Off Mode: When oven device 10 is not used for a
specified period of time, the stand-by mode is discontinued and the
auto-off mode begins. In the auto-off mode, the display indicates
"OFF" and the heating elements are not energized. Actuation of any
of push-buttons 58a-58e will reactivate the stand-by mode by
beginning the curing mode sequence. The specified time is factory
set to a value between 0 and 60 minutes. Of course, the specified
time period could also be user modifiable.
[0042] Curing Mode Sequence: The controller automatically executes
a curing mode when oven device 10 is turned on (using, for example,
a rocker switch 62 mounted to front surface 50 of control unit 40,
shown in FIG. 62), or when exiting the auto-off sequence. During
curing mode sequence, the heating elements are turned on at full
power for 60 seconds, then full off for 10 seconds and the display
reads "StbY" to indicate the standby status of oven device 10.
During the curing mode, oven device 10 cannot be put into its
normal run sequence. When the curing sequence has been completed,
the controller automatically goes into the stand-by mode.
[0043] The setup (i.e., programming) procedure for the run-time
sequence is as follows: First, the appropriate program switch
58a-58e and enter switch 58h are pushed simultaneously. For
example, if program no. 1 is to be adjusted, program switch 58a and
enter switch 58h are pushed at the same time for 3 seconds; if
program no. 2 is to be adjusted, program switch 58b and enter
switch 58h are pushed at the same time for 3 seconds, etc. Second,
after the appropriate program has been selected, the green LED
60a-60e over the selected program switch 58a-58e is illuminated,
upper amber LED 56b is lit and alphanumeric display 54 indicates
the power level value which is currently programmed ("P.sub.--40"
for the 40% power level). Third, each time enter switch 58h is
pushed, display 54 scrolls to the next programmable sequence. Each
sequence includes four values: (1) the upper power level value
(upper amber LED 56b is lit; display 54 shows, e.g., "P.sub.--40");
(2) the upper time value (upper amber LED 56b is lit; display 54
shows, e.g., "T.sub.--65"); (3) the lower power level value (lower
amber LED 56a is lit; display 54 shows, e.g., "P.sub.--40"); and
(4) the lower time value (lower amber LED 56a is lit; display 54
shows, e.g., "T.sub.--65"). Fourth, at each step, up and down arrow
buttons 58f and 58g can be used to increase or decrease the values.
Fifth, when all of the values have been properly adjusted,
activation of the respective program button 58a-58b causes the
controller to accept the changes. After 15 seconds of no activity,
however, the controller is programmed to exit the programming mode
without accepting the changes. Sixth, activation of any of the
other, non-selected program buttons 58a-58e during the programming
process will cause the adjustments to be manually cancelled. After
being programmed, the user actuates each program button 58a-58e to
activate the desired heating sequence.
[0044] The setup procedure for the standby mode is as follows.
First, enter button 58h and up arrow button 58f are pushed
simultaneously for 3 seconds. Second, display 54 indicates the
power level value currently programmed (e.g., "P.sub.--40") for use
during the standby mode. The power level can then be adjusted by
pushing up and down arrow buttons 58f and 58g. Third, enter button
58h is activated to accept the new value. Fourth, if no adjustments
are made after 15 seconds, the controller exits the standby
programming mode without accepting the changes. Fifth, activation
of any program switch 58a-58e during the standby programming will
cause the controller to exit standby setup mode without accepting
any of the changes that were made.
[0045] The operation of the displays and lamps is as follows.
First, if a program has not been selected, oven device 10 is in
standby mode and LED display 54 will show "rEdY". Second, on
release of any of the five "start buttons" (i.e., program buttons
58a-58e), LED display 54 will show the time (e.g., "T.sub.--83"),
and the display will begin to count down in one second increments.
Third, when the time has elapsed, display 54 will flash or blink
the message "dOnE" for 6 seconds, all of the green LEDs 60a-60e
will flash for 6 seconds and the annunciator will beep for 6
seconds. Pressing any of buttons 58a-58h during this 6 second
period will cancel the annunciator but will not start the program
sequence. Fourth, after the 6 seconds have elapsed, display 54 will
indicate "rEdY". Then, whenever the upper element(s) 48 are
energized, upper amber LED 56b will be energized and whenever the
lower element(s) 46 are energized, the lower amber LED 56a will be
energized.
[0046] The operation of the annunciator is as follows. First, the
annunciator will beep in response to every push of one of buttons
58a-58h to verify the entry. Second, when a normal timing sequence
has been completed, the annunciator will energize as described
above. Third, preferably, the annunciator circuit includes a DIP
switch or other device to allow the user to remove the annunciator
function.
[0047] During a normal run time sequence, pushing any of buttons
58a-58h prior to the completion of the timing cycle will cancel
that run time sequence, and will cause the controller to enter the
standby mode. At that point, the operator can press another of the
program buttons 58a-58e to start another heating sequence.
[0048] A number of components are mounted external to oven device
10. The external components include a plurality (i.e., four) of
rubber or plastic supports 64 attached to the four corners of base
12 to provide support for oven device 10 on a support surface (not
shown), such as a restaurant kitchen countertop. A pair of axial
fans or blowers 66 are mounted to the back of rear wall 18 so that
axial fans 66 can blow ambient air through heating cavity 34. The
airflow provided by axial fans 66 evenly distributes the heat
within heating cavity 34, thereby preventing the back of the
serving plates placed within heating cavity 34 from getting too hot
while preventing the front of the serving plates from getting too
cool (which otherwise may occur since heating cavity 34 is open in
the front and closed in the rear). The air flow cools the glass
panel 44 for upper heating element 48, and prevents the heat from
being applied unevenly to food products 36 being heated.
Alternatively, in a pass-through oven wherein both the front and
back of the heating cavity are open (to allow food products to be
inserted at one end and taken out from the other end), its likely
that no axial fan will be needed since the heat will be more evenly
distributed.
[0049] An electrical power cord 68 passes through a grommet 70 into
the interior of control unit 40 to provide the electrical energy
needed to run oven device 10. To provide a cooling air flow to the
interior components of control unit 40, the rear surface of control
unit 40 can be provided with louvers 72, and a cooling fan 74 can
also be mounted on that rear surface to blow cooling air into
control unit 40.
[0050] As shown in FIGS. 1-5, a wire rack 76 is provided to support
food items 36 above lower glass panel 42. Wire rack 76 preferably
slides into heating cavity 34 using rails or other mounting guides
along the cavity's inside surfaces. Alternatively, the food items
can be supported directly on lower glass panel 42.
[0051] Thus, the on and off operation of heating elements 46 and 48
can be independently controlled by a timing circuit which provides
predetermined timing and power level sequences appropriate for the
heating application. The timing can be started manually by the
operator using a switch 58a-58e mounted to the housing of the oven.
Alternatively oven device 10 can be started automatically by a
switch coupled to wire rack 76 which is actuated when the food
carrying device is placed into the oven onto rack 76. The latter
switch can be activated, initiating the heating cycle, by the
weight of the food carrying device on rack 76. Further, the latter
switch could be a micro-switch activated by a paddle or other
device as the paddle is struck by the food carrying device when
that device is inserted into the oven.
[0052] In one embodiment, heating elements 46 and 48 are
individually controlled by a series of timers operable to delay the
start and independently cycle the heating elements to give the
precise amount of heat required to be applied to the upper and
lower surfaces of the food product without burning or scorching the
food product. In one embodiment, the oven device could be
configured to automatically eject the food products from the
appliance at the end of the heating process.
[0053] Referring to FIGS. 7-9, a reflective wall panel 80 for the
oven device is shown according to a further embodiment of the
invention for improving the balance and distribution of browning
and cooking of food items 36 placed within heating cavity 34 by
dispersing and dissipating the radiant heat energy emitted from
heating units 32 and 38. Reflective wall panel 80 may be integrated
into oven device 10 in particular to replace the need for blowers
66. Accordingly, wall panel 80 is used to disperse heating
properties such that fans 66 are not needed to provide even heating
of items placed into heating cavity 34. In an exemplary embodiment,
wall panel 80 may replace rear wall 18 of FIG. 1. A
vertically-oriented frame member 82 is formed having a generally
rectangular profile with an upper mounting surface 84, a lower
mounting surface 86, a first side mounting surface 88 and a second
side mounting surface 90. The frame member 82 includes a generally
planer border portion 92 surrounding a generally rectangular
opening 94 that may have rounded corners.
[0054] A reflective panel insert 96 is formed having a corrugated
surface 98 shown schematically in FIG. 7, and defined by a series
of alternating peaks 100 and valleys 102 for providing a radiant
heat reflective surface for more uniformly dispersing and
dissipating radiant heat energy emitted by heating units 32 and 38
for improving the balance and distribution of browning and cooking
of the food items 36 placed within heating cavity 34. Peaks 100 and
valleys 102 are shown preferably having a linear and horizontal
orientation, but may also be configured having a linear and
vertical orientation (not shown). In alternative embodiments, the
reflective pattern of peaks 100 and valleys 102 may be circular or
any other suitable pattern for enhancing the radiant heat energy
dispersal and dissipation necessary to meet the heating needs of
particular food items according to the particular geometrical
proportions of cavity 22 and the configuration of heating elements
46 and 48.
[0055] Reflective panel insert 96 may be removably attached to an
inner side of frame portion 92 by, for example, welding or
fasteners (e.g., screws, rivets, etc.). The separability of frame
portion 92 from reflective panel insert 96 facilitates the
interchange of panel inserts having varying reflective patterns
within a single frame member for customizing the radiant heat
dissipation and dispersion properties of the ovens to suit the
variety of applications necessary for the food service industry.
Alternatively, panel insert 96 and frame portion 92 may be made
from an integrally formed member.
[0056] A bracket member 104 is securely attached horizontally along
a lower portion of frame member 82 and reflective panel insert 96
to complete the reflective wall panel 80. The elevation of bracket
member 104 is located to interface with, and support, lower glass
panel 42. Bracket member 104 may be provided with apertures 108
aligned with apertures 110 on frame member 82 for securing bracket
member 104 to frame member 82 with fasteners. Alternatively,
bracket member 104 may be secured to frame member 82 in any other
suitable manner such as welding or riveting. Bracket member 104 may
also be attached horizontally to an upper portion of frame member
82 to support upper glass panel 44. For embodiments of oven device
10 having vertically planer heating units (not shown), bracket
member 104 may be oriented vertically on frame member 82 to support
corresponding vertically planar glass panels (not shown).
[0057] Frame member 82, reflective panel 96 and bracket member 104
are preferably manufactured from food grade stainless steel sheet
stock (e.g., type 304) having a thickness of approximately 0.036
inches and a 2B surface finish according to any well known stamping
and bending process. However, frame member 82, reflective panel 96
and bracket member 104 may be formed of other suitable materials
(e.g., aluminum, aluminized steel, chrome-plated carbon steel,
etc.) and having any suitable thickness and surface finish for
providing suitable radiant heat reflecting properties and for
interfacing with adjacent components of oven device 10.
[0058] Reflective wall panel 80 may be adapted to fit along the
interior of oven device 10 in a generally parallel orientation to
one or more of the base 12, the left side wall 14, the right side
wall 16, the rear wall 18 and the top 20, whereby the face of
reflective panel insert 96 is exposed through opening 94 toward
cavity 22 of oven device 10 for obtaining the desired radiant heat
energy distribution performance. A plurality of fastener apertures
106 may be provided along upper mounting surface 84, lower mounting
surface 86, first side mounting surface 88 and second side mounting
surface 90 for attaching wall panel bracket 82 to the base 12, the
left and right side walls 14 and 16, rear wall 18 and top 20.
[0059] In alternative embodiments, a reflective panel member may be
unitarily or integrally formed with a frame member for mounting
within the desired locations of the oven and the relative angle and
spacing of the corrugation peaks and valleys on the reflective
panels may be adjusted or modified to any appropriate pattern for
obtaining the desired radiant heat distribution performance for
uniformly cooking, heating or browning a variety of food items.
[0060] Thus, oven device 10 is capable of rapidly melting or
browning the top surface of food items or complete meals, while
also heating the serving plates or other food support assembly in
addition to heating the food product itself. Testing of a prototype
showed that oven device 10 reduced the heating time for melting or
browning by a factor of three compared to the time needed by a
conveyor oven. The reduced heating time is due to the rapid heating
of heating elements 46 and 48, combined with the
microprocessor-based control sequences which allow both the heating
times and power levels to be programmed for different types of food
items. The high level of control allows the rapid-heating and high
power-output heating elements to rapidly heat the food items
without scorching or burning the food items. The Halient heating
elements used by oven device 10 reach operating temperatures within
a few seconds (e.g., about 1-3 seconds from room temperature), and
testing of a prototype showed that the air within the heating
cavity reached a temperature of about 450.degree. F. at a 25% power
level within 1-2 seconds of the power being applied.
[0061] Oven device 10 also provides significant advantages with
respect to the Salamander broiler. For example, while the
Salamander broiler must be left on continually, oven device 10 can
be turned on and off as needed, thereby decreasing both energy
usage and the amount of heat vented into the kitchen. The decreased
heat vented into the kitchen allows the exhaust hood or other
ventilation method needed for the Salamander broiler to be
dispensed with, and results in savings in air conditioning and
ventilation costs. Another advantage of oven device 10 is that the
edge of the serving plate or other food support assembly (i.e., the
rim) need not be directly exposed to the radiant energy generated
by the heating elements. This allows the operator to pick up the
plate or dish by its rim without the need for insulated gloves or
other means, which would not be possible with a conveyor oven.
[0062] While the embodiments shown in the FIGS. and described above
are presently preferred, it should be understood that these
embodiments are offered by way of example only. The invention is
not intended to be limited to any particular embodiment, but is
intended to extend to various modifications that nevertheless fall
within the scope of the appended claims. For example, different
configurations of the oven can be used, such as closed-end or
pass-through ovens. The types, sizes, numbers and geometrical
arrangements of the heating elements can be modified depending on
the application of the oven device. The type of control unit can be
changed, and different types and numbers of programmable or
non-programmable timers can be used. Other modifications will be
evident to those of skill in the art.
* * * * *