U.S. patent number 3,818,171 [Application Number 05/257,185] was granted by the patent office on 1974-06-18 for microwave cooking apparatus.
This patent grant is currently assigned to Sage Laboratories, Inc.. Invention is credited to Paul F. Harhen, Matthew S. Miller.
United States Patent |
3,818,171 |
Miller , et al. |
June 18, 1974 |
MICROWAVE COOKING APPARATUS
Abstract
An eye-level microwave oven having a set of cooking burners
disposed therebelow includes a ventilation duct extending
vertically from a bottom chamber of the apparatus to the microwave
oven. The duct may terminate at either the bottom or the back of
the microwave oven.
Inventors: |
Miller; Matthew S. (Holliston,
MA), Harhen; Paul F. (Milford, MA) |
Assignee: |
Sage Laboratories, Inc.
(Natick, MA)
|
Family
ID: |
22975242 |
Appl.
No.: |
05/257,185 |
Filed: |
May 26, 1972 |
Current U.S.
Class: |
219/757; 312/236;
219/680; 126/21A |
Current CPC
Class: |
H05B
6/6429 (20130101) |
Current International
Class: |
H05B
6/80 (20060101); H05b 009/06 () |
Field of
Search: |
;219/10.55,399,400
;126/21A ;312/214,236 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Truhe; J. V.
Assistant Examiner: Jaeger; Hugh D.
Claims
What is claimed is:
1. A cooking apparatus comprising;
a bottom section having a plurality of upright walls, a back wall
and a bottom plate defining a chamber having at least one port for
carrying air from outside the apparatus to the chamber, said
chamber being a source of relatively cool air,
a top section including a microwave oven having electrical
components including a magnetron, and a circulating blower with an
air intake port,
means intermediate the top and bottom sections for structurally
interconnecting the top and bottom sections with the top section
disposed at normal eye level,
and a ventilation duct that continuously extends from said bottom
chamber to said microwave oven,
said microwave oven having an opening for receiving the top end of
the ventilation duct and said bottom section having a rear wall
defining in part the chamber, said rear wall having an opening for
receiving the bottom end of the ventilation duct,
said ventilation duct having a cross-sectional area smaller than
the cross-sectional area of the opening from the rear wall defining
the bottom chamber.
2. The apparatus of claim 1 wherein the cross-sectional area of the
duct is larger than the cross-sectional area of the opening in the
microwave oven.
3. The apparatus of claim 2 wherein the blower and duct are
constructed to pass air at a rate of approximately 80 cubic feet
per minute.
4. The apparatus of claim 3 wherein the cross-sectional area of the
intake port of the blower is smaller than the cross-sectional area
of the opening in the microwave oven to which the duct is
coupled.
5. The apparatus of claim 4 wherein said duct has a rectangular
cross-section.
6. The apparatus of claim 5 wherein said microwave oven has an
output air vent and means defining an output plenum chamber for
receiving area from the blower and exiting air via the output air
vent.
7. The apparatus of claim 6 wherein said bottom chamber, duct and
blower are for conveying air to the microwave oven for the purpose
of cooling the components therein, said air flow being continuous
from said bottom chamber to said microwave oven.
Description
BACKGROUND OF THE INVENTION
Some commercially available cooking apparatus includes a set of
cooking burners which may be gas or electric burners, and an
eye-level oven disposed thereabove. The eye-level oven is also
operated typically by either gas or electricity.
In accordance with the present invention, the conventional eye
level oven is replaced by a microwave oven of approximately the
same size, and disposed above the cooking burners of the apparatus.
The microwave oven is powered by a magnetron, or the like. The
magnetron may have a maximum allowable operating temperature on the
order of 235.degree. F, and thus if the magnetron of the microwave
oven is not properly ventilated continuous operation of the oven is
not possible when heat is being generated therebelow from the
conventional cooking burners.
In a commercial microwave oven, there is generally no heat
generated below the oven, and the oven is not normally confined in
a small space. However, the eye-level microwave oven, which is
primarily meant for use in a dwelling place, has heat generated
therebelow and is also usually disposed against a wall. Thus, the
usual ventilation techniques used in commercial microwave ovens do
not provide adequate magnetron cooling in the eye-level microwave
oven application.
Accordingly, one important object of the present invention is to
provide an improved microwave cooking apparatus including an
eye-level microwave oven.
Another object of the present invention is to provide a microwave
cooling apparatus in accordance with the preceding object and
including ventilation means coupled to the microwave oven for
cooling the energy source of the oven even when excessive heat is
being generated below the oven. The energy source or magnetron must
be suitably cooled so that its temperature is maintained below a
predetermined shut-off temperature thereby providing continuous
operation of the microwave oven under virtually all operating
conditions.
A further object of the present invention is to provide a microwave
cooling apparatus in accordance with the preceding objects wherein
a conventional eye-level oven can be used and easily adapted for
microwave cooking.
SUMMARY OF THE INVENTION
To accomplish the foregoing and other objects of the present
invention, there is provided a cooking apparatus having a typical
set of cooking burners which may be either gas or electric
operated, and a microwave oven disposed above and spaced from the
cooking burners. In accordance with one aspect of the present
invention, the cooking apparatus has an enclosed chamber at the
bottom thereof, and there is provided a ventilation duct preferably
vertically arranged, and extending from the bottom chamber of the
apparatus to the microwave oven. In one embodiment of the invention
the ventilating duct terminates at the bottom of the microwave oven
and in an alternate embodiment the duct terminates into the back of
the microwave oven.
In a preferred embodiment, the duct has a rectangular cross section
of a first area and the opening into the microwave oven is
dimensioned having a second area, wherein the first area is
preferably larger than the second area for providing adequate air
flow. The blower that is provided in the microwave oven for
circulating the air adjacent the magnetron, or the like, has an
intake aperture that is preferably circular and should have a cross
section no larger than the said second area.
BRIEF DESCRIPTION OF THE DRAWINGS
Numerous other objects, features and advantages of the invention
will now become apparent upon a reading of the following detailed
description taken in conjunction with the accompanying drawings, in
which:
FIG. 1 is a perspective view of a microwave cooking apparatus
constructed in accordance with the principles of the present
invention;
FIG. 2 is a side view of the apparatus of FIG. 1 partially in cross
section showing one embodiment for the ventilation duct;
FIG. 3 is a back view of the cooking apparatus of FIG. 1;
FIG. 4 is a perspective view of the microwave oven section of the
cooking apparatus of FIG. 1 partially cut away to show the
compartment containing the energy source for the oven; and
FIG. 5 is a side view similar to the one shown in FIG. 2 partially
in cross section of another embodiment of the ventilation duct of
the present invention.
DETAILED DESCRIPTION
Referring now to the drawings, and in particular to FIG. 1, there
is shown a perspective view of a cooking range 10 that is basically
of conventional design but includes a microwave oven 12 in place of
the conventional eye-level oven. The range includes cooking burners
14 which may be either electric, gas or the like, burners and their
associated controls 16. The range is basically constructed of sheet
metal, may have a baked enamel finish and may include a storage
area in the bottom portion 18 of the range.
An upwardly extending intermediate portion 20 interconnects the
bottom portion 18 with the rear of the microwave oven 12. The
microwave oven preferably has an insulating sheet 22 disposed
therebelow to provide a limited amount of insulation between the
heat generated from the burners 14 and the microwave oven
itself.
The range 10 is typically constructed as depicted in the cutaway
section in FIG. 1, with the side walls 24 extending rearwardly to
form a back cavity 26 (see also FIG. 3). As indicated in FIG. 2,
the bottom portion 18 is also constructed so that there is an open
bottom chamber 28 that forms an enclosed chamber when the range is
supported on a floor or the like. This bottom chamber 28 is vented
at the front vent 30. Referring now to FIGS. 2 and 3, there is
shown respective side and back views of the cooking range
indicating the position for the vertical ventilating duct 32. Duct
32 connects from the bottom chamber 28 through an opening 34 in the
back wall 36 defining the chamber 28. The duct 32 may be
constructed of sheet metal and its upper end terminates in an
opening 38 in the back wall 40 of the microwave oven. Thus, the
bottom chamber 28 is a source of relatively cool input air coupled
from input vent 30 and the vertical duct 32 carries this relatively
cool air to the microwave oven 12.
Referring now to FIG. 4 there is shown a perspective view of the
microwave oven 12 partially cutaway to diagrammatically show some
of the internal components comprising the oven. The oven comprises
a bottom insulating plate 22, a top plate 44 and an intermediate
plate 46. The oven also comprises a front door 48 and a number of
vertically extending walls 50 which define an oven cooking area 52
and a component storage area 54.
The space provided between top wall 44 and intermediate wall 46
defines an output plenum chamber 45 having an output vented opening
56 and an input opening 58 which communicates with the blower 60 in
the area 54. Area 54 also contains a magnetron 62 or the like and
means 64 which may be a wave guide for coupling the energy from the
magnetron to the cooking cavity 52.
The blower 60 may be of conventional design and includes a
circulating fan 66 having an input port 68. FIG. 4 also shows the
opening 38 in the back wall 40 which terminates the top end of the
vertical duct 32.
When the oven was operated without the use of a vertical duct and
with the use of a rear input port, there was not sufficient cooling
provided for the magnetron, and thus the temperature limit switch
associated therewith caused intermittent operation of the
magnetron. Typically, the magnetron should not be operated at its
cooling fins in excess of approximately 235.degree. F. With the use
of a vertical duct interconnecting to the bottom chamber 28
sufficient cooling was provided to enable continuous operation of a
magnetron. Also, this operation was tried with all of the burners
14 on which would be the worst case condition.
In accordance with one aspect of the present invention, it was
discovered that the cross sectional area A1 of the duct 32 should
be larger than the cross section of the opening 38. In one
embodiment the ventilation duct 32 has an 8 .times. 1 1/2 inch
cross section and the opening 38 has a 7 .times. 1 1/2 inch
opening. Alternatively, the area A1 should not be made too much
larger than the area A2 as this would decrease the velocity of the
air moving up the vertical duct 32. The air should be drawn up the
duct at approximately 80 cu. ft. per minute. It is also preferred
that the opening 34 in the bottom be slightly larger in area than
the area A1. The dimensions of this opening may be 8 inches by 2
inches for example.
In accordance with a further aspect of the present invention, it
was found that the opening 38 in the rear wall 40 of the microwave
oven should not be any smaller than the cross sectional area A3 of
the input port 68 of the blower 60. In one embodiment the diameter
of the input port 68 is 2 3/4 inches and the area A3 is
approximately 9 sq. in. The area of opening 38 is approximately 10
1/2 sq. in. The air passes from the output port 58 of the blower 60
and is vented through vents 56 preferably in the front, top portion
of the microwave oven.
FIG. 5 shows an alternate arrangement for the vertical duct 32. The
duct 32 couples from the bottom chamber 28 to the bottom of the
microwave oven and the opening terminating the top of the vertical
duct 32 may be the same size as opening 38 shown in FIG. 4.
Alternatively, the top end of duct 32 may extend through bottom
insulated wall 22 and terminate slightly above this wall internal
of the oven. With the duct in this position, the cooling is
approximately the same as discussed hereinbefore with reference to
FIGS. 1-4.
Having described a limited number of embodiments of the present
invention, it should now be obvious that numerous other embodiments
will fall within the spirit and scope of the present invention
which is defined by the appended claims.
* * * * *