U.S. patent application number 11/830411 was filed with the patent office on 2009-02-05 for conveyor oven with multiple heating zones.
Invention is credited to Frank Anthony AGNELLO, Constantin BURTEA, Sanda BURTEA, Don VAN ERDEN.
Application Number | 20090034944 11/830411 |
Document ID | / |
Family ID | 40338238 |
Filed Date | 2009-02-05 |
United States Patent
Application |
20090034944 |
Kind Code |
A1 |
BURTEA; Sanda ; et
al. |
February 5, 2009 |
CONVEYOR OVEN WITH MULTIPLE HEATING ZONES
Abstract
Multiple top-mounted heaters and at least one bottom heater
define multiple heating/cooking zones in a conveyor oven. The
top-mounted heaters output different energy levels and thereby
define heating/cooking zones whereat foods are cooked differently.
By using multiple bottom-mounted heaters, thermal separation of the
heating zones can be further enhanced. Liquids, such as air, water,
oil or a combination of all three can be sprayed onto foods during
the cooking process to control cooking.
Inventors: |
BURTEA; Sanda; (Lindenhurst,
IL) ; BURTEA; Constantin; (Lindenhurst, IL) ;
BURTEA; Sanda; (Lindenhurst, IL) ; AGNELLO; Frank
Anthony; (South Elgin, IL) ; VAN ERDEN; Don;
(Wildwood, IL) |
Correspondence
Address: |
LADAS & PARRY LLP
224 SOUTH MICHIGAN AVENUE, SUITE 1600
CHICAGO
IL
60604
US
|
Family ID: |
40338238 |
Appl. No.: |
11/830411 |
Filed: |
July 30, 2007 |
Current U.S.
Class: |
392/310 ;
126/21A |
Current CPC
Class: |
A21B 2/00 20130101 |
Class at
Publication: |
392/310 ;
126/21.A |
International
Class: |
F24C 1/02 20060101
F24C001/02; F24C 15/32 20060101 F24C015/32 |
Claims
1. An oven comprising: a cavity having a top, a bottom, a first
opening and a second opening; a single, loop conveyor within the
cavity, the loop conveyor (conveyor) extending between and capable
of moving items on the conveyor in a first direction that is from
the first opening to the second opening, the conveyor having a
first side and a second side, the first and second sides defined by
a geometric line extending between, and substantially orthogonal
to, the first and second openings; a first top-mounted heater which
directs infrared heat downwardly, infrared heat from the first
top-mounted heater being directed toward the first side of the
conveyor; a second top-mounted heater which directs infrared heat
downwardly, infrared heat from the second top-mounted heater being
directed toward the second side of the conveyor; and a first bottom
mounted heater which directs infrared heat upwardly toward the
first and second sides of the conveyor.
2. The oven of claim 1, wherein the conveyor is a variable speed
conveyor.
3. The oven of claim 1 further comprised of a baffle between the
first and second top-mounted heaters, said baffle directing and
reflecting heat from the first top-mounted heater toward the first
side of the conveyor and directing and reflecting heat from the
second top-mounted heater toward the second side of the
conveyor.
4. The oven of claim 1, wherein the first and second top-mounted
heaters are capable of having infrared heat output levels that are
different from each other and wherein the infrared heat output
levels of the first and second top-mounted heaters are separately
and individually adjustable.
5. The oven of claim 4 wherein at least one of the first and second
top-mounted heaters are electrically-powered quartz heaters.
6. The oven of claim 5 further comprised of an electrical resistor
electrically connected between the first and second top-mounted
heaters to determine the heat output from the first and second
top-mounted heaters.
7. The oven of claim 5 further comprised of a first variable power
source coupled to and providing power to the first top mounted
heater and a second variable power source coupled to and providing
power to the second top mounted heater.
8. The oven of claim 4 wherein at least one of the first and second
top-mounted heaters are gas-fired infrared heaters.
9. The oven of claim 1 wherein the first bottom-mounted burner is
an electrically-powered quartz heater.
10. The oven of claim 1 wherein the first bottom-mounted burner is
a gas-fired burner.
11. The oven of claim 1 wherein the first bottom-mounted heater
directs infrared heat upwardly toward the first side of the
conveyor and wherein the oven includes a second, bottom-mounted
heater directing infrared heat upwardly toward the second side of
the conveyor.
12. The oven of claim 11, wherein the heat output of the first
bottom-mounted heater and the heat output of the second
bottom-mounted heater are separately and individually
adjustable.
13. The oven of claim 12 further comprised of an electrical
resistor electrically connected between the first and second
bottom-mounted heaters to determine the heat output from the first
and second bottom-mounted heaters.
14. The oven of claim 12 further comprised of a first variable
power source coupled to and providing power to the first
bottom-mounted heater and a second variable power source coupled to
and providing power to the second bottom-mounted heater.
15. The oven of claim 1, wherein substantially more than fifty
percent (50%) of the infrared heat energy from the first
top-mounted heater is directed to the first side of the conveyor
and substantially more than fifty percent (50%) of the infrared
heat energy from the second top-mounted heater is directed to the
second side of the conveyor.
16. The oven of claim 1 wherein the single variable speed conveyor
has a width dimension that is orthogonal to the conveyor's
direction of rotation and wherein the geometric line defining the
first and second sides is at the middle of the width dimension.
17. The oven of claim 1 further comprised of an air blower, which
causes air to flow over portions at least one of the first and
second sides of the conveyor.
18. The oven of claim 1 further comprised of an air blower, which
controls food cooking by causing air to flow through a space within
the oven that is between the top-mounted heaters and the
conveyor.
19. The oven of claim 1 further comprised of a sprayer, which
sprays a liquid above the conveyor.
20. The oven of claim 1 further comprised of a sprayer, which
controls food cooking by spraying a liquid onto a food item on the
conveyor.
21. The oven of claim 23, wherein the liquid is water.
22. The oven of claim 23, wherein the liquid is a cooking oil.
23. An oven comprising: a cavity having a top, a bottom, a first
opening and a second opening; a single, variable-speed loop
conveyor (conveyor) within the cavity, the conveyor extending
between and moving food on the conveyor in a first direction that
is from the first opening to the second opening, the conveyor
having a first side and a second side, the first and second sides
defined by a geometric line extending between, and substantially
orthogonal to, the first and second openings; a first set of
top-mounted heaters, the first set of top-mounted heaters directing
infrared heat downwardly toward the first side of the conveyor; a
second set of top-mounted heaters, the second set of top-mounted
heaters directing infrared heat downwardly toward the second side
of the conveyor; and a first bottom mounted heater which directs
infrared heat upwardly toward the first and second sides of the
conveyor; wherein the infrared heat output of each top heater is
individually controllable.
24. The oven of claim 23 further comprised of at least one baffle
between the first and second sets of top-mounted heaters, said
baffle directing and reflecting heat from the first set of
top-mounted heaters toward the first side of the conveyor and
directing and reflecting heat from the second set of top-mounted
heater toward the second side of the conveyor.
25. The oven of claim 23 wherein the heaters of at least one set of
the first and second sets of top-mounted heaters are
electrically-powered quartz heaters.
26. The oven of claim 23 wherein the heaters of at least one set of
the first and second sets of top-mounted heaters are gas-fired
heaters.
27. The oven of claim 23 the first bottom-mounted burner is an
electrically-powered quartz heater.
28. The oven of claim 23 the first bottom-mounted burner is a
gas-fired burner.
29. The oven of claim 23 wherein the first bottom-mounted heater
directs infrared heat upwardly toward the first side of the
conveyor and wherein the oven includes a second, bottom-mounted
heater directing infrared heat upwardly toward the second side of
the conveyor.
30. The oven of claim 23, wherein substantially more than fifty
percent (50%) of the infrared heat energy from each heater in the
first set of top-mounted heaters is directed to the first side of
the conveyor and substantially more than fifty percent (50%) of the
infrared heat energy from each heater in the second set of
top-mounted heaters is directed to the second side of the
conveyor.
31. The oven of claim 23 wherein the single variable speed conveyor
has a width dimension that is orthogonal to the conveyor's
direction of rotation and wherein the geometric line defining the
first and second sides is at the middle of the width dimension.
32. The oven of claim 23 further comprised of an air blower, which
causes air to flow over portions at least one of the first and
second sides of the conveyor.
33. The oven of claim 23 further comprised of an air blower, which
controls food cooking by causing air to flow through a space within
the oven that is between the top-mounted heaters and the
conveyor.
34. The oven of claim 23 further comprised of a sprayer, which
sprays a liquid above the conveyor.
35. The oven of claim 23 further comprised of a sprayer, which
controls food cooking by spraying a liquid onto a food item on the
conveyor.
36. The oven of claim 34, wherein the liquid is water.
37. The oven of claim 34, wherein the liquid is a cooking oil.
38. The oven of claim 23, wherein for a first food item placed on
first side of the conveyor and for a second food item placed along
side the first food item but on the second side of the conveyor,
for any conveyor speed, the total amount of heat energy input to
the first food item by the first set of top-mounted heaters is
different than the total amount of heat energy input to the second
food item by the second set of top-mounted heaters, when said first
and second food items move from the first opening to the second
opening.
39. An oven comprising: a cavity having a top, a bottom, a first
opening and a second opening; a single, variable-speed loop
conveyor (conveyor) within the cavity, the conveyor having a width
dimension and located between the first opening and second opening,
the conveyor having first, second and third lanes that correspond
to first, second and third segments of the conveyor's width; a
first set of top-mounted heaters, mounted above the first lane and
directing infrared heat downwardly toward the first lane of the
conveyor; a second set of top-mounted heaters mounted above the
second lane and directing infrared heat downwardly toward the
second lane of the conveyor; a third set of top-mounted heaters
mounted above the third lane and directing infrared heat downwardly
toward the third lane of the conveyor; and at least one bottom
mounted heater which directs infrared heat upwardly toward the
first, second and third lanes of the conveyor; wherein the infrared
heat output of each top heater is individually controllable such
that the heat energy input to a first food item placed in the first
lane of the conveyor at the first opening can receive different
amounts of heat energy input to second and third food items placed
in either of the second or third lanes but where food items placed
alongside each other in the first, second or third lanes arrive at
the second opening at the same time.
40. The oven of claim 39 further comprised of at least one baffle
between each of the sets of top-mounted heaters, the baffle between
each set directing and reflecting heat from the sets of top-mounted
heaters toward corresponding conveyor lanes.
41. The oven of claim 39 wherein the top-mounted heaters are
electrically-powered quartz heaters.
42. The oven of claim 23 wherein the top-mounted heaters are
gas-fired heaters.
43. The oven of claim 39 wherein the at least one bottom mounted
heater is an electrically-powered quartz heater.
44. The oven of claim 39 wherein the first bottom-mounted burner is
a gas-fired burner.
45. The oven of claim 39 wherein the first bottom-mounted heater
directs infrared heat upwardly toward the first lane of the
conveyor and wherein the oven includes a second, bottom-mounted
heater directing infrared heat upwardly toward the second lane of
the conveyor and wherein the oven includes a third, bottom-mounted
heater directing heat upwardly toward the third lane of the
conveyor.
46. The oven of claim 39 further comprised of an air blower, which
causes air to flow over portions at least one of the first, second
and third lanes of the conveyor.
47. The oven of claim 39 further comprised of an air blower, which
controls food cooking by causing air to flow through a space within
the oven that is between the top-mounted heaters and the
conveyor.
48. The oven of claim 39 further comprised of a sprayer, which
sprays a liquid above at least one of the first, second and third
lanes of the conveyor.
49. The oven of claim 39 further comprised of a sprayer, which
controls food cooking by spraying a liquid onto a food item on the
conveyor.
50. The oven of claim 49, wherein the liquid is water.
51. The oven of claim 49, wherein the liquid is a cooking oil.
52. The oven of claim 49, wherein for a first food item placed in
the first lane, and for a second food item placed in the second
lane and for a third food item placed in the third lane, said
first, second and third items being placed adjacent to each other,
for any conveyor speed, the total amount of heat energy input to
the first food item is capable of being different than the total
amount of heat energy input to either the second or third food
items when said first, second and third food items move from the
first opening to the second opening.
Description
BACKGROUND
[0001] This invention relates to ovens used to cook foods. More
particularly, this invention relates to high-capacity conveyor
ovens, which are often used in restaurants and food service
operations.
BRIEF DESCRIPTION OF THE DRAWINGS
[0002] FIG. 1 is a front view of a conveyor oven with multiple
heating zones;
[0003] FIG. 2 is a top view of the interior of the oven shown in
FIG. 1, taken through section lines 2-2;
[0004] FIG. 3 is a left side end view of the oven shown in FIG.
1;
[0005] FIG. 4 depicts an embodiment of electrical heaters used in
various oven embodiments;
[0006] FIG. 5A is a schematic diagram showing how power control is
achieved in one embodiment of the oven;
[0007] FIG. 5B is a schematic diagram of an electrical equivalent
of the electrical heaters depicted in FIG. SA.
[0008] FIG. 5C depicts another embodiment of how power control is
achieved in yet another embodiment;
[0009] FIG. 6A is a perspective view of the oven shown in FIG. 1
with the housing removed showing the placement of multiple top
mounted heaters but also showing the placement of a bottom mounted
heater;
[0010] FIG. 6B is a perspective view of the oven shown in FIG. 1
with the housing removed showing the placement of multiple top
mounted heaters but also showing the placement of multiple bottom
mounted heaters;
[0011] FIG. 7 is a left end view of the oven depicted in FIG. 1
with a heat deflecting/reflecting baffle mounted between the two
top mounted heaters;
[0012] FIG. 8 is an end view of an alternate embodiment of the oven
depicted in FIG. 1 showing two spatially-separated top-mounted
heaters with a baffle between them and with liquid sprayers that
dispense various liquids over foods on the conveyor in order to
control cooking of various food items on the conveyor;
[0013] FIG. 9 is a left side end view of a conveyor oven with three
separate cooking lanes, each of which has its own top and bottom
mounted infrared heaters;
[0014] FIG. 10 is a side view of a multi zone conveyor oven shown
in FIG. 9 having separately controllable top and bottom infrared
heaters and but also having liquid dispensers along the conveyor
path to effectuate cooking control of food items on the
conveyor.
DETAILED DESCRIPTION
[0015] FIG. 1 shows a side view of a conveyor oven 10 with multiple
heating zones. The oven 10 is comprised of a cavity 12 having a top
14, a bottom 16, a first opening 18 on the left side and a second
opening 20 on the right side. A single, closed-loop, variable speed
conveyor 22 extends between and passes through the first opening 18
on the left side and the second opening 20 on the right side and
carries food items through the oven 10 in the direction shown by
arrow 24. A controller 32, implemented with a microprocessor (not
shown), memory (not shown) and control electronics (not shown)
control the delivery of electric power and combustion gas and with
a display 33 and input keypad 34
[0016] FIG. 2 shows a top view of the interior of the oven 10 shown
in FIG. 1 taken through section lines 2-2. The conveyor 22 has a
width, W, which is depicted in FIG. 2 as being divided into two
sides that are identified by reference numerals 26 and 28 by a
geometric center line 30. (The sides 26 and 28 of the conveyor 22
can also be considered to be zones, pathways, lanes or
regions.)
[0017] The center line 30 of the conveyor 22 runs parallel to the
conveyor's direction of travel 24 and orthogonal to the second
openings 18 and 20. In the embodiment shown in FIG. 2, the first
side 26 and the second side 28 are each one half the width W of the
conveyor such that each of the sides' widths are equal to w/2 as
shown. Alternate and equivalent embodiments include first and
second sides 26 and 28 that are of unequal widths.
[0018] A salient aspect of the dual or split zones 26 and 28 of the
conveyor 22 is that food items placed on either side 26 or 28 of
the conveyor 22 at an input end of the oven 10 will arrive at the
output end at substantially the same time, assuming of course they
are placed side-by-side or adjacent to each other when they're in
put to the oven. If the heat energy supplied to one side of the
conveyor 22, is controlled vis-a-vis heat energy supplied to the
other side of the conveyor 22, the time that different foods spend
in the oven will be equal but their doneness when they exit the
oven will be different or varied.
[0019] FIG. 3 depicts a left-side end view of the oven 10 depicted
in FIG. 1 and FIG. 2. Two, side-by-side, electrically-powered
top-mounted heaters 32 and 36 (end views of them shown) produce and
direct infrared (IR) heat 33 downwardly toward areas of the
conveyor 22 beneath them. Infrared heat 33 from the first or
left-side top-mounted heater 32 is directed toward the first or
"left" side 26 of conveyor 22. Infrared heat 37 from the second or
"right" side top-mounted heater 36 is directed downwardly toward
the second or "right" side 28 of the conveyor 22. In the embodiment
shown in FIG. 3, a single bottom-mounted heater 38 directs infrared
heat upwardly toward the conveyor 22 and toward the bottom of food
items on the conveyor 22.
[0020] A food item placed on the left or first side 26 of the
conveyor 22 such that it is beneath the first or left-side heater
32 will be cooked by heat energy coming from the bottom heater 38,
but also by heat energy directed downwardly from the left-side
heater 32. Similarly, a food item placed on the right or second
side 28 of the conveyor 22 such that it is beneath the second or
right-side heater 36 will be cooked by heat energy coming from the
bottom heater 38, but also by heat energy directed downwardly from
the left-side heater 36. The cooking of an item in the first side
26 can therefore be controlled and different from the cooking of an
item in the second side 28 simply by controlling heat from the two
separate top-mounted heaters 32 and 36.
[0021] In the embodiment shown in FIG. 3, a spatial separation of
the first heater 32 from the second heater 36 helps to define two
separate, i.e. multiple, heating lanes (also considered to be
zones, pathways or regions) 26 and 28 due to the fact that most of
the heat 33 from the first heater 32 will be directed onto a
corresponding zone or area of the conveyor 22 directly below the
first heater 32. Similarly, the infrared heat 37 from the second
heater 36 will be directed substantially straight downwardly onto a
corresponding area or region of the conveyor 22 immediately below
the second heater 36. In alternate embodiments, such as those
depicted in FIG. 7 and FIG. 8, the top mounted heaters 32 and 36
are substantially contiguous, owing to the fact that they use
electric heating elements constructed as shown in FIG. 4.
[0022] FIG. 4 depicts an electric heating element used in
embodiments of the conveyor oven 10 with multiple heating zones.
The first or left side heater 32 is made up of boustrophedonic
windings of electrically resistant wire or "cal rod" attached to a
substantially planar and thermally-resilient substrate (not shown).
The second or right side heater 32 is also made up of
boustrophedonic winding of electrically resistant wire. It is
important to note that the two windings of electrically-resitive
wire that make up the left and right side heaters are connected in
series with each other. In such an embodiment, the electrical
resistance per unit length is the same, but the number of windings
41A in the first heater 32 is greater than the number of windings
41B in the second heater 36 and their spacing is closer. Since the
number of windings in the side 32 is greater that the number of
windings in the second side 36, and since the winding spacing is
closer in the first heater 32 than in the second heater 36, the
heat output from the first heater 32 is inherently greater than the
infrared energy output from the second heater 36. Thus, by
appropriately winding electrically resistant conductors, one of the
heaters depicted in FIG. 3 is capable of having an infrared heat
output level that is different from the infrared heat output level
from the other heater. Those of ordinary skill in the art will
recognize that while the windings depicted in FIG. 4 are
boustrophedonic, crenellated windings could also be used as well as
spiral or circular windings.
[0023] FIG. 5A depicts an end view of another embodiment of the
oven shown in FIG. 1 wherein infrared output energy levels of the
two, top-mounted heaters 32 and 36 are adjusted by a resistor 44
between power supply 42 and the second heater 36. FIG. 5B is a
schematic diagram of the electrical equivalent circuit of the
embodiment shown in FIG. 5A. The resistor 44 in series with the
second heater 36, which is an electrically-resistive wire form a
voltage divider with the voltage across the heater 36 being
determined by the voltage drop across the resistor 44. For any
energy source 42, the power dissipated by the second or right side
heater 36 will be a function of its resistance and the resistance
of the control resistor 44. By varying the value of resistor 44,
the infrared energy level input to the second or right side 28 of
the oven can be controlled with respect to the power level
delivered to the left or first side of the oven 26.
[0024] FIG. 5C shows another embodiment of the 10 oven wherein the
first and second top mounted heaters 32 and 36 generate different
infrared output levels. The first top mounted heater 32 is driven
by its own separately and individually controllable power supply
48. The second top mounted heater 36 is driven by its own power
supply 50. The power supplies 48 and 50 are separately and
individually controlled by a processor 52, which executes stored
program instructions. The processor 52 also receives commands that
are entered into a user interface 54 on the front panel of the oven
10 shown in FIG. 1.
[0025] In addition to separately and individually controlling IR
from the top-mounted heaters 32 and 36, IR from the bottom heater
38 is also controllable through the CPU 52. In one embodiment the
bottom mounted infrared heater 38 is gas fired. Infrared energy
output from the bottom heater 38 is controlled by modulating the
amount of gas supplied to a gas-fired heater, or, adjusting the
electrical energy provided to a resistive heater.
[0026] FIG. 6A shows a perspective view of the oven 10 shown in
FIG. 1 albeit with the cabinet removed in order to show the
placement and orientation of multiple top mounted heaters 32 and 36
on both sides 26 and 28 of the conveyor 22. The top heaters
identified by reference numerals 32A and 32B comprise a first set
of top mounted heaters that direct infrared heat downwardly toward
the conveyor 22 left or first side 26. The top heaters identified
by reference numerals 36A and 36B comprise a second set of top
mounted heaters that direct infrared heat downwardly toward the
conveyor 22 right or second side 28. The bottom mounted heater 38,
the width W' of which is substantially equal to the width W of the
conveyor, directs heat upwardly toward both sides of the conveyor
22.
[0027] In a preferred embodiment, the IR output from each heater
32A, 32B, 36A and 36B, and 38 shown in FIG. 6A is separately
controllable by controlling the electrical power delivered to each
heater. In an alternate embodiment, the left or first side heaters
32A and 32B are controlled together but their heat output is
variable vis-a-vis the right or second side heaters 36A and 36B
such that both left side heaters can be either increased or
decreased relative to both right-side heaters.
[0028] FIG. 6B shows yet another embodiment, wherein the sets of
top mounted heaters are separately and individually controlled,
however, in FIG. 6B, several bottom-mounted heaters 38 are
provided. In one embodiment, each of the bottom-mounted heaters is
individually controllable with respect to the others. In another
embodiment, the left side, bottom-mounted heaters (one shown and
identified by 38A) are controlled together with respect to the
right-side bottom-mounted heaters (two shown, identified by
reference numerals 38B and 38C).
[0029] The foregoing figures depict conveyor ovens with multiple
heating zones 26 and 28, which are effectuated by multiple
top-mounted heaters that direct IR downwardly and onto an area
directly below the heaters. One or more bottom-mounted heaters
direct IR upwardly. By controlling or varying the IR delivered to
the different sides of the conveyor, the cooking that occurs on one
side of the conveyor will be different than the cooking that occurs
on the other side of the conveyor to thereby provide a conveyor
oven with multiple cooking/heating zones.
[0030] Those of ordinary skill in the art know that infrared energy
is a form of electromagnetic energy. It will therefore disperse as
it travels from the heaters toward the conveyor. Since the IR
disperses as it travels from the heaters, at least some of the IR
emitted from a top mounted heater in one zone will reach one or
more other zones. Experimentation revealed that more than 50% of
the IR from a top mounted heater reached the conveyor area directly
below the heater, with the balance being lost to adjacent spaces.
Experimentation also showed that the thermal separation of the two
zones 26 and 28 can be effectively improved (and less heat directed
to adjacent zones) more cooking differences between the two zones
26 and 28 significantly enhanced by the use of a baffle 60 located
between the heaters to deflect and/or reflecting IR emitted from
one heater. The baffle 60 is believed to cut off the IR waves that
disperse from the heater toward adjacent zones.
[0031] The baffle 60 is preferably a relatively rigid stainless
steel panel or vane that extends downwardly from the top 14 of the
oven 10. The further that the baffle 60 extends downwardly the
greater will be its separation effect. Extending the baffle 60
downwardly all the way to the conveyor 22 will completely separate
the IR emitted from the top mounted heaters, however, a baffle that
extends from the oven top 14 to the conveyor might limit the types
of foods that the oven can accommodate.
[0032] Additional experimentation revealed that the reflection and
deflection effectuated by the baffle 60 varies by the angle .theta.
formed between the baffle 70 and a line normal to the oven's top
surface 14. When the baffle 60 is at an angle .theta., relative to
the plane of the top 14, the baffle effectively directs and
reflects infrared heat from the second heater 26 toward the second
or right side zone 28 such that substantially less than 50% of the
IR heat output from the second heater 36 reaches the first side 26
of the conveyor 22. It is believe that the baffle 60 effectuates
greater thermal separation between the first zone 26 and the second
zone 28.
[0033] In the embodiment of the element shown in FIG. 6B,
additional thermal separation between the two zones or lanes 26 and
28 by using at least one bottom-mounted baffle 61.
[0034] FIG. 8 shows yet another end view of the oven depicting the
first zone 26. One or more liquid dispensers or sprayers 64 and 66
dispense (e.g., spray or mist) a liquid 70 onto food items placed
on the conveyor belt 22 in order to vary cooking time. In one
embodiment, the dispensers 64 spray water, cooking oil, seasonings
or air, as the food items enter the oven. Dispensing water or a
cooking oil onto food items necessitates more input heat energy in
order to cook a food item. Dispensing any form of liquid, whether
gas or solid, can significantly affect the cooking process that
takes place in the oven 10 because oil, water or heat will require
the absorption and dissipation of heat provided by the heaters.
Dispensing liquids can thereby slow the cooking process.
[0035] In one embodiment, the liquid dispensed into the conveyor
oven is high pressure air, which effectuates a temperature drop or
cooling over one or both of the conveyor zones. The liquid can also
be oil, water, or solutions of seasonings or a combination
thereof.
[0036] FIG. 9 depicts yet another embodiment of a conveyor oven
with multiple cooking zones. Food items can be placed in three
separate zones or lanes, which are identified by reference numerals
26, 28, and 76 to be cooked by corresponding first, second and
third sets of top-mounted infrared heaters identified by reference
numerals 32, 36 and 74 respectively. In the embodiment shown in
FIG. 9, the heaters of each set of top mounted heaters, are
individually controllable with respect to each other. Each heater
directs infrared energy downwardly onto a corresponding area of the
conveyor 22 directly beneath each heater. Top mounted baffles 60A
and 60B separate the top mounted heaters from each other but also
separate the infrared heat emitted from each heater by reflecting
and directing infrared heat from adjacent heaters, downwardly to
thereby provide greater control.
[0037] The first, second and third lanes 26, 28 and 76 are further
defined by separate individually controlled bottom heaters 38A,
38B, and 38C. The bottom heaters can also be separated by baffles
to further direct and reflect infrared energy emitted from
them.
[0038] In FIG. 9, each of the lanes 26, 28 and 76 is substantially
equal in width. Alternate embodiments would of course include
different widths with respect to each other.
[0039] By providing separate and individually controllable top
mounted infrared heaters and separate and individually controllable
bottom mounted heaters, the amount of heat energy input to food
items in each of the lanes 26, 28 and 76, can be varied to
effectuate a different doneness to food items in each of the food
lanes. Food items cooked in one lane can be cooked differently than
food items in a different lane with the food items in each lane
arriving at the output side of the oven at the same time.
[0040] By way of example, if the infrared energy output from the
heaters in the first lane 26, is greater than the infrared energy
output from the heaters in the third lane 76, identical or
substantially identical food items placed in first and third lanes
at the conveyor input end, will be cooked differently as they pass
through the oven 10. The food item cooked in the first lane will be
more well done, i.e., cooked more, than the food item in the third
lane but both food items will arrive at the output or right end 20
at the same time.
[0041] The conveyor oven 10 with multiple heating zones depicted in
the figures and described and claimed herein provides significant
advantages over prior art conveyor ovens, especially to restaurants
and food services that provide made-to-order foods. Three people,
who dine together at a restaurant and who each order steaks, but
who prefer them cooked rare, medium and well, can have their steaks
cooked to match their preferences but with each party's steak being
ready to be served at the same time. Different constituents of a
food item, such as a toasted sandwich, and which require different
levels of cooking but which should also be ready at the same time,
can be easily prepared and their cooking concluded simultaneously
using the conveyor oven with multiple heating zones.
[0042] FIG. 10 is a side view of another embodiment of a multi zone
conveyor oven. In FIG. 10, additional cooking control is
accomplished by multiple liquid dispensers 66A, 66B and 66C, which
are distributed lengthwise along the conveyor 22 and which dispense
liquids such as air, water or cooking oil or seasonings onto food
items as they pass through the oven 10.
[0043] In the embodiments shown in each of the figures the top
mounted heaters were electrically powered quartz heaters. In one
embodiment the top mounted heaters are identical in that they use a
substantially baustrophodontic electrically resistant wire the
number of windings and spacing of which are identical on each side
or in each zone. In an alternate embodiment, the number of windings
is greater and the spacing is narrower as shown in FIG. 4 with a
fixed power level applied to both sides. In yet a third embodiment,
the power control resistor can be used between a power supply
source and one of the heaters to effectuate power control.
[0044] In the embodiments described above, the top-mounted heaters
are electrically powered whereas the bottom-mounted heaters are gas
fired. In an alternate embodiment, either of the top and bottom
mounted heaters, or both can be gas fired heaters such as the gas
fired heater disclosed in the inventors' co-pending patent
application, the U.S. serial number of which is, Ser. No.
11/692,465, and which is entitled, Infrared Emitting Gas Burner,
the teachings of which are incorporated by reference herein in
their entirety. The ability to control or provide different amounts
of heat energy to different food items traveling on the same
conveyor allows for variable cooking control of different food
items used in the same food product or service.
[0045] The description and embodiments set forth above are for
purposes of illustration and not limitation. The appurtenant claims
define the scope of the invention disclosed herein.
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