U.S. patent number 3,701,872 [Application Number 04/704,389] was granted by the patent office on 1972-10-31 for heating and loading implement for microwave energy.
Invention is credited to Melvin L. Levinson, 1 Meinger Street.
United States Patent |
3,701,872 |
|
October 31, 1972 |
HEATING AND LOADING IMPLEMENT FOR MICROWAVE ENERGY
Abstract
A process and an implement for converting microwave energy into
heat energy which includes a body having a plurality of resistive
particles therein. Upon subjecting the particles to microwave
irradiation, a plurality of electric arcs are generated throughout
the particles, thereby resulting in the microwave energy being
converted into heat energy, and the electric arcs serving as a load
for the microwave irradiation source. The implement is particularly
useful with microwave ovens.
Inventors: |
Melvin L. Levinson, 1 Meinger
Street (Avenel, NJ 07001) |
Family
ID: |
24829270 |
Appl.
No.: |
04/704,389 |
Filed: |
February 9, 1968 |
Current U.S.
Class: |
219/759; 219/730;
426/243 |
Current CPC
Class: |
H05B
6/6402 (20130101); H05B 6/74 (20130101); H05B
6/6494 (20130101) |
Current International
Class: |
H05B
6/80 (20060101); H05B 6/74 (20060101); H05b
009/06 () |
Field of
Search: |
;219/10.55
;338/223,224,225 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Schwenklragen, German Application 1,120,619 printed Dec. 28, 1961
.
(Kl21h36), 2 pages spec., 2 sheets drawings. .
Copson, "Microwave Heating" 1962 The Avi Publishing Co., Westport,
.
Conn., pages 283-285.
|
Primary Examiner: J. V. Truhe
Assistant Examiner: Hugh D. Jaeger
Attorney, Agent or Firm: John J. Lipari
Parent Case Text
CROSS-REFERENCES TO RELATED APPLICATIONS
This application is a continuation-in-part application of my
copending applications, U.S. Ser. No. 470,809, now abandoned, filed
July 9, 1965, and U.S. Ser. No. 483,144 now abandoned, filed Aug.
27, 1965.
Claims
1. In combination, means defining an oven cavity, a source of
microwave energy connected to said cavity, an implement in said
cavity, comprising: a body permeable to microwave energy, said body
containing a plurality of resistive particles so disposed, which
when exposed to microwave irradiation, results in a multitude of
arcs being generated therethrough
2. In an oven, cavity, according to claim 1, wherein said
microwave
3. In an oven cavity, according to claim 1, wherein the resistive
particles
4. In an oven, according to claim 1, wherein the implement further
includes a heat conducting element having at least one opening
therein for permitting the passage of microwave irradiation to the
resistive particles to load the microwave emitting means and to
permit an equal distribution
5. In an oven, cavity, according to claim 2, wherein the implement
is provided with at least one surface forming a shelf and said
cavity is
6. In an oven, according to claim 5, wherein the cavity contains a
second
7. In a microwave oven having a shelf and means for emitting
microwave energy into said oven, the improvement in said shelfing
comprising: a first member of a microwave permeable material shaped
to conform to the interior perimeter of the cavity with which it is
to be used, a second member of a microwave absorptive material, and
a plurality of rods of a heat conducting material embedded within
the second member and arranged in a preselected pattern which will
convey the heat generated within the material of said second member
in the presence of microwave energy to an oven load, said second
member and said rods being so disposed that the heat generated
within said absorptive material
8. An implement for heating an article for use in an oven chamber
receptive to microwave radiation comprising, a first member of a
microwave permeable material, a second member of a microwave
absorptive material, and a heat conducting member in a preselected
relationship with said second member for conducting the heat
generated by said second member in the
9. An implement, according to claim 1, wherein a portion of said
body is of
10. An implement, according to claim 9, wherein said body includes
means for supporting an article in heat conducting relationship
with said
11. An implement according to claim 10, wherein said means is a
grill.
Description
This invention relates to an implement which in response to
microwave irradiation is capable of processing and/or cooking a
load. More particularly, this invention relates to an implement
capable of converting microwave energy into heat energy which may
thence be directed to an object to be processed.
Microwave ovens are extremely useful as cooking ovens; however,
with conventional type microwave ovens, the searing, browning and
crusting of foods constitutes a problem and requires either
additional gas or electric heating elements in the microwave oven
or the use of an externally located heating apparatus not related
to the microwave oven. It is apparent that the heretofore methods
employed for searing, browning and crusting are cumbersome, costly,
time-consuming and generally unappealing to the users thereof.
Accordingly, one of the objects of this invention is a process for
converting microwave energy into heat energy.
Another object of this invention is to provide an implement
directly associated with microwave ovens so as to lend versatility
to the cooking of foodstuffs. Advantageously, foodstuffs can be
fried, roasted, grilled and baked with the desired crusting surface
thereon.
Another object of this invention is to provide a microwave oven
capable of cooking a foodstuff with a desired crusting surface
thereon.
Still another object of this invention is to provide an implement
for a microwave oven which, per se, is capable of acting as a dummy
load for a microwave emitting source.
According to the objects of this invention, an implement,
preferably taking the form of a cooking utensil or microwave oven
shelf, is provided with a plurality of relatively small particles
of resistive material therein. In response to receipt of microwave
irradiation from a microwave source, a multitude of electric arcs
are generated throughout the particles, thus resulting in the
emitted microwave energy being converted into heat, and the
electric arcs serving as a load for the microwave source.
Other objects and a fuller understanding of the invention may be
had by referring to the drawings wherein:
FIG. 1 is a cross-sectional view of the implement taking the form
of a cooking utensil;
FIG. 2 is a cross-sectional view of another embodiment of the
implement taking the form of a "hot cube";
FIG. 3 isA CROSS-SECTIONAL SIDE VIEW OF A MICROWAVE OVEN HAVING
INCORPORATED THEREIN ANOTHER EMBODIMENT OF THE IMPLEMENT IN THE
FORM OF A SHELF;
FIG. 4 is a view taken along line 4 -- 4 of FIG. 3;
FIG. 5 is a cross-sectional side view of a microwave oven having
incorporated therein another embodiment of the implement in the
form of a shelf;
FIG. 6 is a cross-sectional front view of a microwave oven having
incorporated therein another embodiment of the implement in the
form of two shelves;
FIG. 7 is a cross-sectional side view of a microwave oven having
incorporated therein another embodiment of the implement in the
form of an electrical charcoal grill; and
FIG. 8 is a partial cross-sectional, plan view of another
embodiment of the implement in the form of a grill-shelf.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference to the drawings, it will be apparent that the
inventive implement may be constructed and utilized in various
embodiments. According to one embodiment, as seen in FIG. 1, an
implement I.sub.1 is in the form of a cooking utensil and includes
a body 10 which is permeable to microwave irradiation and
preferable made of glass-ceramic type material, such as Pyroceram
(manufactured by Corning Glass Works) or Cer-Vit (manufactured by
Owens-Illinois). Located within body 10 is a bed or layer of
particles 11 of a resistive material supported on an insulating
medium 12 which may be of a material such as GR-25 (manufactured by
General Refractories Company). A good heat conducting element 13,
in the form of a plate, copper strips, rods, etc., is preferably
located in contact with the particle bed 11. The heat conducting
element 13, as illustrated in FIG. 1, preferably is a flat copper
plate provided with openings 15--15 therethrough to permit the free
random passage of microwave waves to and through the particles. In
the event it is desired to utilize implement I.sub.1 as a dummy
load, per se, for a microwave emitting source, the heat conducting
element 13 may be provided with a plurality of fins 16--16, as seen
in phantom, which extend from the implement structure to cause a
free release of heat therefrom. A top processing surface 17, made
of a material similar to body 10, is in contact with heat
conducting element 13, and is attached to the body at 18 by a
suitable adhesive.
It has been found that the resistive particles 11 are, in
actuality, a plurality of electrodes which support a plurality of
spark gaps to discharge microwave energy therebetween. There are
innumerable solid metals which will support an electric gap or arc.
For example, the particles may be of a ferrite material having a
high resistance to produce a relatively cool spark, when it is
desired to use the implement as a household cooking utensil. On the
other hand, a carbon material which possesses low resistance and
produces a relatively hot spark may be utilized, when the implement
is desired to be used in a refractory process for vaporizing
metals. With the latter, ultra high heat temperatures may be
obtained when considering carbon's melting point (approximately
6,500.degree. F).
With respect to the heat insulation 12, it is of a material, such
as described above, which is permeable to microwave energy and not
lossy or self-heating when exposed to microwave energy. The heat
insulation has a dual purpose; firstly, to direct the heat to the
workload and, secondly, when the implement is used as a cooking
utensil, to protect the cook and confine the heat generated by the
arcing from a table subsequently receiving the implement.
Regarding the body or casing 10, it should be of a material, such
as stated above, which is permeable to microwaves and not lossy or
self-heating when exposed to microwave energy. The body is used to
protectively contain the fragile heat insulating material and the
loose pile or layer of resistive particles. Generally, the body or
casing is constructed by sealing two portions together, one portion
holding the particles and the other enclosing the particles and
serving as a cooking surface.
With respect to heat conducting element 13, it is of a material,
such as stated above, which is capable of equalizing the heat
generated. The heat conducting material may be of the same material
as the resistive particles or of a material complementary thereto,
such as copper having a low resistance and ferrite having a high
resistance. It is apparent, however, that materials having a low
melting point, such as aluminum, may not be used with materials
having a high melting point, such as carbon, when temperatures in
excess of the low melting point material are required.
In operation, the implement is located in a suitable microwave
cavity (not shown) and exposed to microwave irradiation, the
microwaves contacting the particles 11. In response thereto, a
plurality of electric arcs are generated throughout and between the
particles 11 and the heat conducting element 13. Within a
relatively short time, the particle bed appears as a glowing bed of
coal emitting a high degree of heat in excess of 1,000.degree. F.
The amount of heat generated is dependent upon the amount and size
of the resistive particles, the quantity of the released microwave
energy and the time. The microwave arcing tends to terminate the
released microwave power and, as a result, precludes a sufficient
degree of reflection of microwave power back to the source, thereby
preventing any damage thereto. It is apparent that the higher the
output power of the microwave generator, the more resistive
particles required to properly terminate it.
FIG. 2 is illustrative of another embodiment of the implement,
referred to as I.sub.2, which takes the form of a "hot cube."
Implement I.sub.2 includes an outer coating 10b of a suitable
microwave permeable material, such as glass-ceramic, epoxy and, in
this instance, preferably cardboard. A simple heat insulating
material 12b, such as sand concrete or castable refractory
material, is located within the outer coating 10b and completely
envelops a bed of resistive particles 11b of a material such as a
relatively inexpensive high-grade iron ore.
After exposure to microwave irradiation, the heat stored within the
"hot cube" releases and can be used advantageously as a warmer for
articles or animals. For example, the "hot cube" may be easily
inserted into insulating containers (not shown) whereupon the
stored heat releases from the "hot cube" to heat or cook a
foodstuff in proximity thereto. Similarly, the "hot cube" may serve
as a body warmer for people. The duration of the released heat is
commensurate with the size and type of insulation coupled with the
quantity of microwave irradiation of the particle bed.
Significantly, in view of this low cost of fabricating a "hot
cube," such may be marketed as a disposable item.
While the implement has heretofore been discussed with respect to
its use as a portable type article; namely a cooking utensil, "hot
cube," body warmer and the like, the implement also may take the
form of a shelf or shelves in a microwave oven. As seen in FIG. 3
and 4, there is illustrated a microwave oven 25 which is provided
with a conventional microwave source 26, such as a generator or
magnetron, for supplying microwave energy into cavity 27 through
waveguide 28. An implement, generally referred to as I.sub.3, takes
the form of a shelf and includes a supporting element 30 for
holding a ceramic type body 10c. Located within the body 10c is an
insulating medium 12c having positioned thereon a plurality of
resistive particles 11c. A heat conducting element 13c, having an
opening 15c extending therethrough, is disposed in contact with the
particles and the top portion 17c of body 10c, the top portion 17c
being capable of receiving a foodstuff "F" thereon through closure
31.
The supporting element 30 is pivotally adjustable at pivot 32
located near the rearmost portion of the oven and is provided with
cooperating adjustable pins 33 near the foremost portion of the
oven for insertion into various openings 34--34 for locking the
implement-shelf I.sub.3 in a desired angular position. As a result
of the angular position of the implement-shelf I.sub.3, any
by-products of cooking, such as rendered fat, which results from
the operation of the microwaves and implement as previously
described, will pass by gravity through opening 35 of a downwardly
converging bottom 36 into a portable container 37 for subsequent
use or disposal.
As seen in FIG. 5, there is illustrated another embodiment of the
invention wherein the implement, referred to as I.sub.5, takes the
form of an upper shelf in an oven 25d. The oven is similar to the
oven in FIGS. 3 and 4 with the exception that the implement-shelf
I.sub.5 is in an inverted position. As seen in FIG. 5, the
implement-shelf I.sub.5 rests on supporting elements 33d-33d and
includes a bottom ceramic or quartz radiant panel 10d. An
insulating medium 12d is provided on the top side of the shelf and
houses a bed of resistive particles 11d therein. The insulating
medium 12d herein takes on the added function of dividing the oven
cavity so as to create a hot lower cavity and a relatively cooler
upper cavity. A conventional bottom shelf 35, permeable to
microwave energy, is provided on supporting elements 36--36 for
holding a utensil 37 with a foodstuff, "F," thereon.
The operation is similar to that previously described with respect
to the oven in FIGS. 3 and 4. Typically, the microwave generator is
turned on and the implement shelf I.sub.5 is preheated until the
radiant panel 10d becomes hot, whereupon a foodstuff is placed
under the radiant shelf. The foodstuff is cooked from both the
microwave irradiation and the infra red radiation. Additionally, if
an extra heavy, relatively darker crust is desired on the
foodstuff, e.g., one which is cooked rare, the implement-shelf
I.sub.5 may be modified by conventional means to be movable, thus
enabling the implement-shelf to be positioned into intimate contact
with the foodstuff for a suitable period of time.
FIG. 6 discloses still another embodiment of the invention wherein
the implement, referred to as I.sub.6 --I.sub.6, takes the form of
a pair of implement-shelves which may either be fixed or movable
with respect to each other. As seen therein, lower implement-shelf
I.sub.6 rests on adjustable supporting elements 33e and is provided
with a bottom portion 12e, a bed of particles 11e and a top
insulating portion 10e which cooperates with the bottom portion to
encase the particle bed. Similarly, upper implement-shelf I.sub.6
rests on adjustable supporting elements 33e and is provided with a
top portion 10e, a bed of resistive particles 11e, and a bottom
insulating portion 12e which encases the particle bed in
cooperation with the top portion. Optionally, a rotating spit 40
driven by a chain 41 connected to a motor (not shown) may be
employed.
The implement shelves I.sub.6 --I.sub.6 may be moved as desired,
i.e., towards each other, either separately or together or into
contacting or nearly contacting relationships with the foodstuff
"F" to obtain additional crusting on opposite sides thereof, in a
similar manner as discussed with respect to FIG. 5. It should be
noted that while manual means are illustrated to show relative
movement of the shelves, suitable conventional mechanical or
electromechanical means may be employed without departing from the
invention.
FIG. 7 discloses still another embodiment of the invention and in
its simplest structure, wherein the implement, referred to as
I.sub.7, takes the form of a microwave charcoal grill. Implement
I.sub.7 is comprised of a body 10f having a plurality of resistive
particles 11f therein. Typically, a ceramic or metallic grill 43,
illustrated with a foodstuff "F" thereon, may either be placed on
or above the particle bed 11f.
A microwave irradiation source 26f is located in the bottom portion
of the oven 27f and, when energized, emits waves through waveguide
27f. The top portion of the oven is provided with a grid 45 having
relatively small openings 46--46. The openings 46--46 are
sufficiently small so as to confine microwave energy therein, yet
sufficiently large to permit the passage of air therethrough for
disposal of by-products of combustion. Upon energization of the
microwave source 26f, conversion of the microwave energy into heat
energy results in a similar manner as hereinbefore described. It
should be noted that if the resistive particles 11f are of a
material, such as carbon, which will ignite when heated in the
presence of air, the burning carbon, burning fat and the microwave
energy will swiftly barbeque the foodstuff "F."
FIG. 8 discloses still another embodiment of the inventive
implement wherein the implement, referred to as I.sub.8, is capable
of taking the form of a grill-shelf which may be used as a
substitute for implement shelf I.sub.3, illustrated in FIG. 3. Here
a ceramic frame 50 holds hollow ceramic or quartz tubes 51 filled
with a plurality of resistive particles 52.
In operation, grill shelf I.sub.8 is positioned in a microwave oven
and preheated whereupon a foodstuff, such as a frozen steak, is
placed thereon. With the aid of the energy from the microwave
source, the steak is defrosted and cooked with a resultant grill
pattern thereon which is similar to that obtained in prior art
steak grilling, the gravy juice being collected in container 37.
Additionally, the ceramic frame implement I.sub.8 remains cool and
can be easily transported with the steak thereon to a receiving
table.
It is to be understood that the above described arrangements of the
various implements are illustrative of the application of the
principal of the invention, each implement employing, at least, a
plurality of resistive particles therein capable of receiving and
converting microwave energy into heat energy. Numerous other
arrangements may be devised by those skilled in the art without
departing from the spirit and scope of the invention. Accordingly,
it is to be understood that the present invention is to be limited
only by the spirit and scope of the appended claims.
* * * * *