Electric heating – Microwave heating – Enclosed cavity structure
Reexamination Certificate
2001-07-05
2003-09-16
Leung, Philip H. (Department: 3742)
Electric heating
Microwave heating
Enclosed cavity structure
C126S29900R, C126S02100R
Reexamination Certificate
active
06621057
ABSTRACT:
FIELD OF INVENTION
The present invention relates to a microwave oven, and more particularly, to a structure of hooded microwave oven in which exhaust and cooling airflow passages are independently formed and an exhaust filter is mounted only in the exhaust airflow passage so as to increase operating efficiency and to reduce flow noise.
BACKGROUND OF INVENTION
First, the constitution of a conventional hooded microwave oven will be described in detail with reference to FIG.
1
.
FIG. 1
is a perspective view of the conventional hooded microwave oven with an outer case thereof removed and an air duct thereof disassembled.
As shown in
FIG. 1
, a cavity
2
in which cooking is done is formed at one side of the microwave oven. An electric equipment installation chamber
4
is formed at one side of the cavity
2
. A plurality of electric equipments
4
′ are mounted inside the chamber
4
. In addition, a blowing fan
8
is mounted on the top of the chamber
4
to form a cooling air stream f
d
toward the chamber
4
.
Furthermore, an exhaust inflow opening
6
is formed in the rear of a back wall of the chamber
4
. The exhaust inflow opening
6
serves as a passage allowing hot air and smoke discharged from a gas oven range (not shown) installed under the microwave oven to flow into the microwave oven.
On the other hand, an air inflow portion
2
a
and an air outflow portion
2
b,
which are constructed by a plurality of passage holes and allow the air to flow into and out of the cavity
2
, respectively, are formed on a top surface of the cavity
2
. Additionally, a guide wall
2
′, which is placed adjacent the air inflow portion
2
a
to guide the air toward the air inflow portion
2
a,
is formed on the top surface of the cavity
2
.
Moreover, an air duct
22
is mounted on the top of the cavity
2
. The air duct
22
is a structure for guiding a sucked exhaust air stream fe of heat and smoke generated from the gas oven range (not shown) installed under the microwave oven toward the front side of the cavity
2
. Engaging protrusions
22
c
are formed at a leading end of the air duct
22
. Also, at the opposing positions of right and left side walls
22
a,
22
b
of the air duct
22
, a pair of support protrusions
22
a
′,
22
b
′ projecting from the respective side walls
22
a,
22
b
are provided. Incline surfaces sloping up toward the rear of the air duct
22
are formed on top ends of the support protrusions
22
a
′,
22
b
′, respectively.
Additionally, an air introduction portion
22
d
is formed outside the left side wall
22
b
of the air duct
22
. The air introduction portion
22
d
has a passage hole in the center portion thereof, and is formed in the shape surrounded by four side walls so as to guide the air downwardly through the passage hole. Furthermore, the air f
c1
that is flowed into the air introduction portion
22
d
is guided by the guide wall
2
′ toward the air inflow portion
2
a
(f
c2
).
Moreover, a ventilation motor
32
c
provided with output shafts (not shown) at both ends thereof is mounted in the rear of the air duct
22
. Sirocco fans
32
c
are mounted at the right and left sides of the ventilation motor
32
c,
respectively. The sirocco fans suck air in the direction of the output shafts (not shown) and discharge the air in the direction orthogonal to the output shafts (not shown). Hereinafter, the left sirocco fan is referred to as a left fan
32
b,
and the right sirocco fan is referred to as a right fan
32
a.
In addition, exhaust openings
32
a
′,
32
b
′ are formed respectively at one side of each sirocco fan. The exhaust openings
32
a
′,
32
b
′ is directed to the air duct
22
to be described below.
Also, an exhaust filter
22
′ is mounted at a front side of the air duct
22
. That is, a lower edge of the exhaust filter
22
′ is supported by the engaging protrusions
22
c
at the leading end of the air duct
22
and a rear surface of the exhaust filter
22
′ is supported by the incline surfaces at the top ends of the support protrusions
22
a
′,
22
b
40
so that the exhaust filter
22
′ is mounted at the front side of the air duct
22
to thoroughly cover the front side of the air flow passage formed in the air duct
22
. Absorbent material is densely filled in the exhaust filter
22
′. By means of the absorbent material, toxic substance in the exhaust discharged through the air duct
22
is filtered so that clean air is discharged from the front side of the exhaust filter
22
′.
On the other hand,
FIG. 2
shows a state that the air duct
22
is mounted on the top of the cavity. Thus, since the air inflow portion
2
a
and the air outflow portion
2
b,
which are formed on the top surface of the cavity
2
, are placed under the air duct
22
, they are hidden. Moreover, at the leading end of the air duct
22
, the exhaust filter
22
′ is obliquely mounted to slope toward the rear of the air duct
22
.
Hereinafter, the flow of air formed inside the microwave oven in the prior art constructed as such will be described with reference to FIG.
2
.
When the ventilation motor
32
c
is operated, contaminated air produced from the gas oven range (not shown) installed under the microwave oven is sucked through the right and left fans
32
a,
32
b
of the ventilation motor
32
c
into the microwave oven and flows as indicated by the arrow f
e
. That is, one portion of the contaminated air flowed into the rear side of the electric equipment installation chamber
4
of the microwave oven through exhaust inflow opening
6
flows toward the right fan
32
a,
and the other portion of the contaminated air flows toward the left fan
32
b.
Meanwhile, as for the flow of air inside the cavity
2
, air drawn into the microwave oven through a ventilation grill (not shown) installed at the left top side of the front of the cavity
2
flows toward the air inflow portion
2
a
through the air introduction portion
22
d
as indicated by the arrow f
c1
. In addition, air drawn into the cavity
2
through the air inflow portion
2
a
evaporates moisture within the cavity
2
, and the air containing the evaporated vapor is discharged from the top of the cavity
2
through the air outflow portion
2
b.
The air discharged from the air outflow portion
2
b
flows into the right fan
32
a
of the ventilation motor
32
c.
As a result, the contaminated air discharged from the gas oven range (not shown) flows through the left fan
32
b
of the ventilation motor
32
c,
whereas not only the contaminated air but also the air containing the vapor in the cavity flows through the right fan
32
a.
As described above, the air sucked into the ventilation motor
32
c
is discharged through each exhaust openings
32
a
′,
32
b
′ to the air duct
22
, and passes through the exhaust filter
22
′ mounted at the leading end of the air duct
22
so as to be discharged forward of the microwave oven. Electric equipments
4
′ in the electric equipment installation chamber
4
are cooled by a separate blowing fan
8
which forms a stream of air by sucking the outside air.
However, the microwave oven having such structure in the prior art gives rise to problems as follows.
First, the contaminated air to be flowed into the right and left fans
32
a,
32
b
of the ventilation motor
32
c
is generated only when the gas oven range is in operation. That is, when only the microwave oven is operated, the contaminated air does not flow into the right and left fans
32
a,
32
b
of the ventilation motor
32
c.
However, even in such case, uncontaminated air discharged forward of the air duct
22
through the right fan
32
a
also unnecessarily passes through the exhaust filter
22
′.
Accordingly, in such case, there is a problem in that the exhaust filter
22
′ does not function as a filter, but obstructs the flow of air passing through the right fan
32
a.
In addition, noise is made when the air passes through a dense filler within the exhaust
Fleshner & Kim LLP
Leung Philip H.
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