Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
`~W~ ~3/~4328 2 1 1 5 ~ 8 0 P~ ;92/02357
Thi s invention relates to inf ra-red oYens ~nd
primarily to comm~rcial o-rens which are compact in
design and int~nded f or rapid cooking of a ~rariety o~
5 different food items.
In smaller commercial establishments, it is oten
d~sirable to pro~ride f ood warmers f ~:r the diæplay of
f ood whe~r~y individual or~2~s may b~o plac~d for
lû :specific: it@ms: displayed. It h~s IlOW becom~ feasible
to cook f ood i t~ms~ to order in such establishmeIlts
uti}izing infra r~d ener~.
I~fra ;red~ erlergy isr partit:~larly sui~ed ~or
smaller cler~ial establishments becau~3 the energy
; 15~ : prc)~uced i9 ~directional and production~does not i~lve
ooking does not~re~uire h~ated air curr~nks whic~ may
be~reIeased ~in~o :the: ambie~t atmospher~ as ~ith
convec~ion oven~:and the li~Q. Whil~ mierowa~e ov~ns
~:~ are also useful in:such establi~hmen~s, microwa~e ov~ns
20 ~ have distin~t disadY~ntages r~lative to th~ inabil ty
to brown bread or rolls and o char the exterior while
cooking m~at~ Microwave oYens, howe~r, a~e compa~t
and suitable for countertop use.
I~ U.S. Pa*ent No. 4,960,977~ assi~d to th~
as~ig~ee of thiB inYention, there wa~ d~scribed a
.
:
:
W~g3/043~8 P~T~VS~2/0235~ '
2115580 2
countertop-type infra-red radiation oven useful t for
example, to cook pizza wherein the article to be cooked
was di~posed upon a mesh turn~able. Infra-red emitters
were disposed below snd above the item to be ooked and
on two of its four sides. Accordingly, as the
turntable rotated, all sides of the food product wexe
expo~ed to radiation for cooking.
In the case of pizza, the sides, bottom, and top
all may have differe~t cooking requir~ments. In the
above-identified infra-red oven, the emitters wëre
separately controlled. In addition, the top emitter
was disposed in a movabl~ shroud which could be
adjusted in height o~er the turntable as desired.
Shielding for the ov~n was no~ ne~essary because
convection curre~ts were not involved in ~he cooking
proce~s and only the dir~ctional radiation of the
emitt~r used.
~ his type of oven was particularly suit~d to the
use of etched foil emitters as con~rasted to the use of
~onve~tio~al ~uartz tubes, nichrome ~ire an~ the like.
~he foil emitters use a relatively low wattage, have a
: rapid wanm-up a~d cool-down, and can be adjusted to the
d~sired medium;range wavelength of cooking energy. In
addit30n, a ~eramic: or other type shield is not
necessary, ::
:~ In certain infra-re~ emitter~ such as that
;~ :described in U.S. Patent ~o. 3,B09~859, a refracto~y
co~r is pro~ided o~er the wire he ting elements, which
cover then is the source of infra-red energy to the
product to be cooked. This type of de~ice then
u~ilizes energy both to heat the refra~tory material
and to then generate suffici ~t ener~y to direct the
: same onto the product to be cooked.
,~ W093/04328 2 1 1 ~ ~ 8 0 P~T/U~9~/023~7
~ , " . 3
It is also ~nown to provide con~eyor o~ens which
utilize infra-red ener~y~ Such de~ices are described,
for example, in U.S. Patents Nos. 4,245,613; 4,554,437;
and 4,615,014. Such ovens are normally multi-zo~e t~p~
oven~ and laxge type installations. In addition, as
described in U.S. Patent No. 4,363,955, conventional
thinking used sh~rtwave energy for food cooking such as
infra-red energy in the wavelength of 1-2 microns as
the preferred energy for cooking. In that l~tter
identified patent, the conveyor o~en utilized was
intended to brown rolls previously partially cooked.
To this end, i~fra-red radiating tubes were pro~ided
across the path of travel of a con~eyor carrying the
indi~idual rolls wi~h a plurality of tubes at the
entrance emitting medium ra~ge microwaves, but the
tubes interior to: the conveyor or tunnel oven bo~h
above a~d below were :short wa~elength emitters.
As described in the above~identi~ied patent, No.
4,960,977, it has been diæ~oYered that medium
wa~elength i~ra~red radiation i5 ~astly desirable for
cooking food~as compared to ~he short ra~g0 spectrum of
1.0 to 2~5 microns. In this way, the cooking can occur
at wavel~ngths in excess of that absorbed ~y wa~r of
up to about~ for example, 4.20 to 4090 microns or
higher.
It has b~en disco~ered that a lightweight and
efficie~t conveyor lor tunnel oven can be pro~ided which
is sufficiently compact to mount on a count~rtop. The
oven of this in~ntion is also sufficien~ly ~ersatil~
to cook a wide variety of foods including pizza, fish
:~ product~, chicken products, and bakery product~.
s ~
~` 211~8~ P~T/US 9 2 / 0 23 5 7
4 03 Rac9d P~ O 1 7AUi~ 1993
The device of this invention utilizes a mesh conveyor belt
which is preferably 18 inches wide and extends ~hrough a heatins
chamber. The chamber mounts, above and below the belt, upper and
lower heating elements which are etched foil heaters. ~he heaters
ar0 disposed sufficiently close to the food items to effect rapid
and efficient cooking. The heaters, however, are separately
controlled. While these heating elem~nts normally disperse infra-
red radiatian at a wavelength of about 3 ~o 6 microns, the
waveLength desired can be provided by alkering the r~sistance on
the heating element as i5 well known to those skilled in the art.
Accordingly, the etched foil heaters of this invention provide a
controlled cooking en~ironment in a predetermined wavelength range
utilizing heaters which minimize the wa~tage required. Etched foil
heaters have a watt density of about 1.08 - 1.24 watts per square
centimeter which is much lower than quartz tube heaters or similar
types of heaters commonly used in cooking en~iro~ments.
The lower heater in the preferred embodiment is spaced only
about 3.8 centimeters below thP conveyor belt, and the upp~x h~ater
is spaced about 7.62 - 10.16 centime~ers aboYe the con~eyor belt.
,
,
.
:~ .
'
.
SUBSTITUTE SHE~ET
.
.
P~T/US 9 ~ / O Z 3 ~ ~
"~''3 2115580 03 ReG~d PCT/P~ 7 AUG 1993
In a preferred embodiment, the oven of this invention is only
42.19 centimeters high, 58.42 centimeters deep, and provides an
opening for the conveyor belt at either side thereof which measures
7.77 centimeters high by 49.38 centimeters long. These J.atter
dimensions are the food prod~ct clearance entering the de~ice.
It has ~urther been discovered that alternate embodiments of
the device of this invention can be pro~ided. In one embodiment,
the conveyor belt feed is continuous through the ov~n. In an
altexnate
~ .
,
SUBSTlTUTE~HEEI
.r~W093/0432g . 2 1 1 5 5 8 0 PCT/US92/02357
embodLment~ the conveyor belt is con~rolled so that it
operates to move the product into the heating area,
hold thP product therein fsr a prede$ermined period of
time, and then move the product out so that khe
proc~dure is a go-stop-go procedure~ In both
instances, electro~ic controllers are pre~erred which
control based on t~me only.
Etched foil heaters have the characteristic~ of
rapid heating and cooling. To accommodate this
characteristic, a timed cycling power input i~ utillzed
in the preferred em~odiment. For ex~mple, full powex
input may be interrupted for a period of 5-15 ~conds
and then xeinitiated for 60-120 seconds. ~lso, a means
to det~rmine if there is no cooking demand for a
cooking cycle for a period of, for example, five
minutes, ~ sensor could turn the power to khe unit off.
In addition, a means for determining the position
of a food: product may be i~corporated ~y an electro-
optical co~tr~l. This de~ice then could be u~ed to
; 20 ensu~e that the food product is po~itioned prop~xly
between both the~top and ~ower heaters~ In this way~
: : use o: the heating elements can ~e contxolled to
maximize cooking efficiency ~t a mi~Lmum of power
re~uire~O
~ Accordingl~ t Ls an object of this invention to
: provide a co~pact co~veyor oven whi~h may be utllized
o~, for eæample,~a co~ntertop and which utilizes etched
~ foil i~fra-red el~ments~as hea~ sources for rapid and
: ~efficient oooki~g. ~ l
3~ It is another object of this invention to provide
alternstive embodLments of a ~co~pa~t conveyor oven
: which either operate continuously or ~perate on an
indexing go-stop-go procedure for coo~ing a wide
WO 93io4328 P~/US /b
2115580
variety of food products f:rom pizza ~o fish a~cl fowl
products or bak~ary produc l:s .
It is yet another ob~e ::t o~ this in~rention to
provide a compact con~reyor o~ren ha~rins~ a controll~r
5 controlling the heat requirements therein by
::ontrolling the power input to upper and to lower
hea~ing elem0nts, s~parately, wherein the haating
elemen~s are ~tched foil. elements to minimlze the
wat~age requiremen~.
These and other objects will become readily
apparent with ref erence to th2 drawings and ~ollowing
de~cription wherein:
Figure 1 is a perspective ~iew of an embod~nent of
15 the o~Ten of thi~ invention.
Figur~ 2 is a sid~ view thereof.
Figure :3 is a top ~iew of the c~en o this
inv~ntion. ~
Figure 4 is a side ~riew of the o~ren of this
~: ,
in~e~tion~showing the two heating el~m~nts.
Fig~re: S is an :alternative embodimsnt of this
invention:in~ol~ing stacked o~e~s.
Fig~re 6A is a schematic of the control cir~uit
for an embodiment o~ t~Ls~ inve~tion using an inde~i~g
: 25 ~: belt ~eed~for~a gOStQp-go me~ns o travel thxough the
o~en of t~is~in~e~tion.
igure~ ~ ~6B: is a: ~Tiew similar to Figu:re 6a o~ly
showir~g the~ ~control circuit for ~ conti~uou~ bE~lt feed
in an e~od:LllLent of this i~vention.
~:~; 30 ~ Pigure 7A is a schematic s~owing the ! control
circuits : for the h~ating elements in a three-pha~e
elem~nt hookup. ~ ~
PC,7/lJ~ 92/o~5~ `
2115S80 ~3 Rec'd P~TJP~O 11 l AUG ~993
Figure 7B is a view simîlar to Figure 7a showing the c~rcuit
for a single-phase element hookup.
Figure ~ is a graph showing a typical fluctuation in the
surface temperature and wavelength over time for a heating circuit
in a device o~ this invention.
Figure 9 is a graph depicting surface temperature against time
illustrating a typical heat up and cool down mode of operation of
~he device of this invention.
Detailed Description of the Invention
With attention to the drawings and to Figures 1-3, in
particular, the device of this invention 10 in its preferred
construction is modular. Accordingly, a housing 12 preferably
mounts a top heater module 14, a bottom heater module 16, and a
control panel 18. Both modules and the control panel preferably
are slidably mounted within the housing 12 and, therefore, can be
easily removed for cleaning, testing, or repair. As shown in
Figure 2, the housing has an opening 20 for a conveyor belt (not
shown) to carry food through the hous.ing 12. In the preferred
embodiment of this invention, the opening 20 is 7.77 centimeter~ by
49.38 centimeters in diameter. This has been found to be adequate
for most food products. In addition, the overall housing depth is
preferred to be 58.42
. ~ :
:
.
.-
~ . .
:
SUB~;T~IJTE SffET
~r ~ 2115580 PCT~ 9 2 / 02~i57
7a ~3 R~'d P~T/P~O 1 1 AUG ~993-
centimeters with the height 42.19 centimeters, the
dimensions shown of the embodiment in the view of Figure 2. This
unit then will accommodate a conveyor beLt with a width of 45.72
centimeters, and meets a desired specification that it~be no more
than 60.96 centimeters deep. It then can be comfortably mounted on
a restaurant counter, or food processing area, or similar location.
The housing 12 includes lateral extensions 22 and 24 for
supporti.ng the conveyor bslt. A conveyor belt support frame member
26
~: :
' ~ ~ ' ' ' '
~:
: ~
. . ,
,
~ ~ ' '' , .
~ . .
SU13STlTlJT~ SHEET
- 2115!~80 PCTI~J~ 92/02357
8 0~ ~ec9d P~T/PT~ l 7 AUG 199
is mounted in each lateral extension 22 and 24 for supporting the
conve~or bel~ (not shown). Lateral support members 28 are provided
for this purpose.
The upstream lateral support 22 further moun~s a c~nveyor belt
sprocket drive shaft 30 for the conveyor belt and a similar shaft
32 is provided downstream at extension 24. A conventional
thumbscrew-type tensioning means 34 is pro~ided on sprock~t 32 to
re~ulate the tension in the bel~. With attention to Figure 4, the
con~eyor belt 36 is shown in phantom ther~in.
Top and bottom heating elemen~s respectively 38 and 40 are
provided in housing 12 above and below the upper flight of the
conveyor belt 36~ These elements are preferably etched foil
heaters obtainable, for example, from Thermal Circuits, Inc., of
Salem, Massachusetts. Thé heaters ~ypically operate in the 3 6
micron wavelength range for optimum cooking and have a watt density
of about 1.08 - 1.24 watts per square centime~er. This is a much
lower watt density than quartz tube heaters that radiate in a wide
wavelength range. As noted above, the wavelength can be further
defined by adding resis~ance as would be ob~iou~ to those skilled
in the art. As will be sub~aquently described, each heating
element 38 and 40 will be separately controlled.
~ .
.
SUi3STlTl~TE SHEFI'
t~C ~ 9 2 / l~ 2~ 5 ~
8a 03 R~c~d P~T/P~O 1 7 AUG 1993
With atten~ion to Figure 3, there is also provided an
illumination means for interior lighting at four locations 42 at,
respectively, the entranc0s and exits to the housing 12 upstream
and downstream of the cooking area.
In addition, an optical indicator 44 may be provided upstream
of the housing 12 whereby when the cooking cycle for one food item
has been completed and
'
: ~ ~
.
,
SUB5~1TUT SH~EE~
~ W093/043Z8 2 1 ~ 5 5 8 0 PCT/US92/02357
a~other food item is not entering th~ housing 12, the
indicators 44 will so advise the controller, and the
controller in turn will shut down ~he heating elements
38 and 40. Electro-~ptical controllers are available,
for example, from Microswitch Di~ision of Honeywell,
Inc., Freepor~, Illinois.
The control panel 18, is part o a control module
~not shown) which rests upon a tray behind the control
panel 18. The controller contains, a3 w~ll be o~ious
to those skilled in the art, all major o~en control
element~. El~ctronically programmable controls
suitable for use in this in~ention can be obtained frvm
United Electric Controls, Inc. of Wa~ertown, Maine or
co~ve~tional controllers, as will be obvious to ~hofie
skill~d in ~he art, may be used to contxol belt peed,
top hea~ and ~tom h~at. In the pref~rred em~od ~ent~
: the Gontrol is by tLme only ra~her than temperature.
With a~tention to Figure 5, ~y using a mounting
collar 46~ a~plurality of units lO can be sta~ked as
0 desiredO ~The collar 46 is merely a con~entional
~ flange-type~col:~ar:~adapted to rest on th~ upper surfa~e
: of housing 12 and receive the lower surf~ce of the next
higher unit to~e s~acked. Obviously, ~he ~upport legs
48 will be removed fr~m the stacked units.
: ~ also ::shown in the Figures, ~he housing 12
pro~ided a~plurali~y of ~ents 50. Internal:fa~ may be
~;~ provided as dQsired. In the preferred embodLme~t, with
:~ refere~ce to ~igure ~4, ventilation fans $2 shown
:~ schematically are provided above the heating element
~ 30 : 3~, ~
:~ The de~ice of this i~vention then is a ~ompact
conveyor ov~n which utilizes upper and lower heating
elements which are e~ched foil heater~. ~he top heater
38 is di~po~ed about 3-4 in~hes above the upper flight
,
,
~~ 2il5~80 PCT/US 9~ / 023 ~7
03 Rec'd PCT/~T~ 1 7 ~UG ~993
of ~he conveyor belt, and the lcwer heater 4~ is d.isposed below the
upper flight o~ the conveyor belt, a distance of about 3.8
centimet~rs. The interior of h~using 12 is further construc~ed of
aluminum coating steel to reflect the infra-red radiation
generated.
As shown in Figure 9, etched foil heaters inherently achieve
a very rapid change in temperature, both in the heating up phase,
and in cool down. As shown in Figure 9, the heat up phase of ahout
six minut~s is satisfackory to produce a temperature above 337.8
degrees C and a wavelength of about 4.5. Cool down occurs
similarly rapidly. Accordingly, i~ may be desixable ~o provide an
interrupted power input whereby for a period of 5 ~o 15 seconds,
power is cu~ off, and reinitiated for 60 to 120 seconds. For
example, in Figure 8, ~he result causes a fluctuating wavelength of
from about 4.5 up ~o about 5 microns and a temperature variation of
abou~ 304.4 to about 371.1 degrees C. The controller above-
: : identified can be so p~ogrammed if desired.
It has been dlscovered as noted above, that a cooking
wavelengkh 4-5 microns i~ optimal a~ compared to short wavelen~ths
in the~1-2 micron range. It is intended, wi~hin ~he scope of this
invention, to encompass any con~entional controller for regulating
the generated heat to a wavelength within the desired range.
~: :
: .
~ SUE~STlTl)T S~EF~
211~58~ P~TIIJS 9 2 / 0 23 5 7
lOa 03 Rgc'd P~TIPT0 l 7 AUG '993
With attention to Figures 7A and 7B, there are depicted
therein a schemati~ in a preferred version of the heater element
hookup of the device of this invention. These schematics are
intended to be illustrative, however, and not limitative. Figure
7A is a tnree-phase element hookup while Figure 7B is a single-
ph~se element hookup. H-l, signifies the
: ~ !
; . : '
SU~S~
-- W093/04328 2 1 1 ~ 5 8 0 PCT/~S92/02357
schematic for the top heater 38 and H-2 simil~rly
identi~ies the lower heater 40. The separate
controllers, CR-1 and CR-2 are reflected in the panel
18.
5Figures 6A and 6~ show, respectively, schema~ics
for the indexing belt eed and a continuous ~elt feed.
In the indexing belt f eed, th~3 belt ad~rances the f ood
product into housing 12 and stops with the product
located between heating elements 38 and 40. This
1 Omovem~3nt would be identif ied by optical sensors 4 4 and
the controller signalled accordingly. In the preferred
em~odiment of this invention, the control i5 by tLme
rather than temperature and, theref ore, af ter a
predetermined period of time, the belt dri~re would ~hen
15index the food out of the housing 12 and onto extension
24 whereupon the belt would stop while the food product
is reme)ved and another f ood product placed at the
er~tranc~, o~ the ~ belt portion in e:~etension 22.
In the continuous belt f eed, ~he belt will run
~0continuously at a ~peed to be determi ned at the control
panel 18 whereby residence tiIr.e within the hc~using 12
wherein ~he heatiny elements ar~3 dispensing inf ra~red
radiation at a predetermined wa~elength or within a
predetermined waYelens~th range, ~he produc:t will be
~5 cooked.
As with Figures ~ 7A and 7B, Figures ~A and 6B are
in~ended to be illu~trative and not l~mitati~Te of this
in~rention . Accordingly, a dif ~rent type of control
s::ircuit or control function is intended to be witHin
30the scop~ of this invention.
The invention may be em~odied in o~her specified
forms without departing from the spirit or ~ssential
:~characteristics thereto. The present embodLments are
therefore to be considered in all respects as
WO93/~4328 ` ~ ` PCT/U~92/02357 ~
211558~ 12
illustrati~re and not restrictive, the s ::ope of the
invention being indicated by the appended claims rather
than by the f oregoing description, and all charlges
which may cc~me within the me~ning and range of
5 e~ui~alency of the lai.ms are th~refore in~ended to bé
embrac~d therein.
,
,
:
, ~,
